Podcasts about microtubule

Play Episode Listen Later Aug 2, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.31.551375v1?rss=1 Authors: Fu, G., Augspurger, K., Sakizadeh, J., Reck, J., Bower, R., Tritschler, D., Gui, L., Nicastro, D., Porter, M. E. Abstract: Ciliary motility requires the spatiotemporal coordination of multiple dynein motors by regulatory complexes located within the 96 nm axoneme repeat. Many organisms can alter ciliary waveforms in response to internal or external stimuli, but little is known about the specific polypeptides and structural organization of complexes that regulate waveforms. In Chlamydomonas, several mutations convert the ciliary waveform from an asymmetric, ciliary-type stroke to a symmetric, flagellar-type stroke. Some of these mutations alter subunits located at the inner junction of the doublet microtubule and others alter interactions between the dynein arms and the radial spokes. These and other axonemal substructures are interconnected by a network of poorly characterized proteins. Here we re-analyze several motility mutants (mbo, fap57, pf12/pacrg) to identify new components in this network. The mbo (move backwards only) mutants are unable to swim forwards with an asymmetric waveform. Proteomics identified more than 19 polypeptides that are missing or reduced in mbo mutants, including one inner dynein arm, IDA b. Several MBO2-associated proteins are also altered in fap57 and pf12/parcg mutants, suggesting overlapping networks. Two subunits are highly conserved, coiled coil proteins found in other species with motile cilia and others contain potential signaling domains. Cryo-electron tomography and epitope tagging revealed that the MBO2 complex is found on specific doublet microtubules and forms a large, L-shaped structure that contacts the base of IDA b that interconnects multiple dynein regulatory complexes and varies in a doublet microtubule specific fashion. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Microtubule association of TRIM3 revealed by differential extraction proteomics

Play Episode Listen Later Jul 28, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.27.549915v1?rss=1 Authors: Glover, H., Mendes, M., Gomes-Neto, J., Ruscilowicz-Jones, E. V., Rigden, D., Dittmar, G., Urbe, S., Clague, M. J. Abstract: The microtubule network is formed from polymerised tubulin subunits and associating proteins, which govern microtubule dynamics and a diverse array of functions. To identify novel microtubule binding proteins, we have developed an unbiased biochemical assay which relies on the selective extraction of cytosolic proteins from cells, whilst leaving behind the microtubule network. Candidate proteins are linked to microtubules by their sensitivities to the depolymerising drug nocodazole or the microtubule stabilising drug, taxol, which are then quantitated in a triplexed mass spectrometry experiment. Our approach is benchmarked by co-segregation of tubulin and previously established microtubule-binding proteins. We then identify several novel candidate microtubule binding proteins. Amongst these, we have selected the ubiquitin E3 ligase TRIM3 (Tripartite motif-containing protein 3) for further characterisation. TRIM3 binding to microtubules is mapped to its C-terminal NHL-repeat region. We show that TRIM3 is required for the rapid accumulation of acetylated tubulin, following treatment with the microtubule stabilising drug taxol. Furthermore, loss of TRIM3, partially recapitulates the reduction in nocodozole-resistant microtubules characteristic of Alpha Tubulin Acetyltransferase 1 (ATAT1) depletion. These results can be explained by a decrease in ATAT1 that follows depletion of TRIM3 that is independent of transcription. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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The 14-3-3/spastin pathway coordinates neurite regeneration and recovery of spinal cord injury by targeting microtubule dynamics

Play Episode Listen Later Jul 27, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.25.550600v1?rss=1 Authors: Liu, Q., Yang, H., Luo, J., Peng, C., Wang, K., Zhang, G., Ji, Z., Lin, H. Abstract: Axon regeneration is abortive in the central nervous system following injury. Orchestrating microtubule dynamics has emerged as a promising approach to improve axonal regeneration. The microtubule severing enzyme spastin is essential for axonal development and regeneration through remodeling of microtubule arrangement. To date, however, little is known regarding the mechanisms underlying spastin action in neural regeneration after spinal cord injury. Here, we use glutathione transferase pulldown and immunoprecipitation assays to demonstrate that 14-3-3 interacts with spastin, both in vivo and in vitro, via spastin Ser233 phosphorylation. Moreover, we show that 14-3-3 protects spastin from degradation by inhibiting the ubiquitination pathway and upregulates the spastin-dependent severing ability. Furthermore, improving the interaction between 14-3-3 and spastin by Fusicoccin (FC-A) promotes neurite outgrowth and regeneration in vitro. Western blot and immunofluorescence results revealed that 14-3-3 protein is upregulated in the neuronal compartment after spinal cord injury in vivo. In addition, administration of FC-A not only promotes locomotor recovery, but also nerve regeneration following spinal cord injury in both contusion and lateral hemisection models. However, application of spastin inhibitor spastazoline successfully reverses these phenomena. Taken together, these results indicate that 14-3-3 is a molecular switch that regulates spastin protein levels, and 14-3-3/spastin pathway is an important target for regulation of microtubule dynamics for nerve regeneration after spinal cord injury. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Collective dynamics of formin and microtubule and its crosstalk mediated by FHDC1

Play Episode Listen Later Jul 25, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.25.550329v1?rss=1 Authors: Tong, C. S., Su, M., Sun, H., Chua, X. L., Guo, S., Ramaraj, R. S., Lee, A. G., Ong, N. W. P., Miao, Y., Wu, M. Abstract: The coordination between actin and microtubule network is crucial, yet our understanding of the underlying mechanisms remains limited. In this study, we used travelling waves in the cell cortex to characterize the collective dynamics of cytoskeletal networks. Our findings show that Cdc42 and F-BAR-dependent actin waves in mast cells are mainly driven by formin-mediated actin polymerization, with the microtubule-binding formin FH2 domain-containing protein 1 (FHDC1) identified as an early regulator. The depolymerization of microtubules coincides with the nucleation of actin waves, and the concurrent release of FHDC1 from microtubule is required for actin waves. Lastly, we show the importance of the actin-microtubule linkage mediated by FHDC1 in crucial cellular processes such as cell division and migration. Our data provided molecular insights into the nucleation mechanisms of actin waves and uncover an antagonistic interplay between microtubule and actin polymerization in their collective dynamics. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Enucleation of the C. elegans embryo revealed the mechanism of dynein-dependent spacing between microtubule asters

Play Episode Listen Later Jul 21, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.21.549990v1?rss=1 Authors: Fujii, K., Kondo, T., Kimura, A. Abstract: The centrosome is a major microtubule-organizing center in animal cells. The intracellular positioning of the centrosomes is important for proper cellular function. One of the features of centrosome positioning is the spacing between centrosomes. The spacing activity is mediated by microtubules extending from the centrosomes; however, the underlying mechanisms are not fully understood. To characterize the spacing activity in the Caenorhabditis elegans embryo, a genetic setup was developed to produce enucleated embryos. The centrosome duplicated multiple times in the enucleated embryo, which enabled us to characterize the chromosome-independent spacing activity between sister and non-sister centrosome pairs. We knocked down genes in the enucleated embryo and found that the timely spacing was dependent on cytoplasmic dynein. Based on these results, we propose a stoichiometric model of cortical and cytoplasmic pulling forces for the spacing between centrosomes. We also found a dynein-independent but non-muscle myosin II-dependent movement of the centrosomes in a later cell cycle phase. The dynein-dependent spacing mechanisms for positioning the centrosomes revealed in this study is likely functioning in the cell with nucleus and chromosomes, including the processes of centrosome separation and spindle elongation. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Mechanical coupling coordinates microtubule growth

Play Episode Listen Later Jun 30, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.06.29.547092v1?rss=1 Authors: Leeds, B. K., Kostello, K. F., Liu, Y. Y., Biggins, S., Asbury, C. L. Abstract: During mitosis, kinetochore-attached microtubules form bundles (k-fibers) in which many filaments grow and shorten in near-perfect unison to align and segregate each chromosome. However, individual microtubules grow at intrinsically variable rates, which must be tightly regulated for a k-fiber to behave as a single unit. This exquisite coordination might be achieved biochemically, via selective binding of polymerases and depolymerases, or mechanically, because k-fiber microtubules are coupled through a shared load that influences their growth. Here, we use a novel dual laser trap assay to show that microtubule pairs growing in vitro are coordinated by mechanical coupling. Kinetic analyses show that microtubule growth is interrupted by stochastic, force-dependent pauses and indicate persistent heterogeneity in growth speed during non-pauses. A simple model incorporating both force-dependent pausing and persistent growth speed heterogeneity explains the measured coordination of microtubule pairs without any free fit parameters. Our findings illustrate how microtubule growth may be synchronized during mitosis and provide a basis for modeling k-fiber bundles with three or more microtubules, as found in many eukaryotes. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Glucose-stimulated KIF5B-driven microtubule sliding organizes microtubule networks in pancreatic beta cells

Play Episode Listen Later Jun 26, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.06.25.546468v1?rss=1 Authors: Bracey, K., Noguchi, P., Edwards, C., Cario, A., Gu, G., Kaverina, I. Abstract: In pancreatic islet beta cells, molecular motors use cytoskeletal polymers microtubules as tracks for intracellular transport of insulin secretory granules. Beta-cell microtubule network has a complex architecture and is non-directional, which provide insulin granules at the cell periphery for rapid secretion response, yet to avoid over-secretion and subsequent hypoglycemia. We have previously characterized a peripheral sub-membrane microtubule array, which is critical for withdrawal of excessive insulin granules from the secretion sites. Microtubules in beta cells originate at the Golgi in the cell interior, and how the peripheral array is formed is unknown. Using real-time imaging and photo-kinetics approaches in clonal mouse pancreatic beta cells MIN6, we now demonstrate that kinesin KIF5B, a motor protein with a capacity to transport microtubules as cargos, slides existing microtubules to the cell periphery and aligns them to each other along the plasma membrane. Moreover, like many physiological beta-cell features, microtubule sliding is facilitated by a high glucose stimulus. These new data, together with our previous report that in high glucose sub-membrane MT array is destabilized to allow for robust secretion, indicate that MT sliding is another integral part of glucose-triggered microtubule remodeling, likely replacing destabilized peripheral microtubules to prevent their loss over time and beta-cell malfunction. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Ninein domains required for its localization, association with partners dynein and ensconsin, and microtubule organization

Play Episode Listen Later Jun 22, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.06.22.546109v1?rss=1 Authors: Tillery, M. M. L., Zheng, C., Zheng, Y., Megraw, T. L. Abstract: Ninein (Nin) is a microtubule (MT) anchor at the subdistal appendages of mother centrioles and the pericentriolar material (PCM) of centrosomes that also functions to organize microtubules at non-centrosomal microtubule-organizing centers (ncMTOCs). In humans, the NIN gene is mutated in Seckel syndrome, an inherited developmental disorder. Here we dissect the protein domains involved in Nin's localization and interactions with dynein and ensconsin (ens/MAP7) and show that the association with ens cooperatively regulates microtubule assembly in Drosophila fat body cells. We define domains of Nin responsible for its localization to the ncMTOC on the fat body cell nuclear surface, localization within the nucleus, and association with Dynein light intermediate chain (Dlic) and ens, respectively. We show that Nin's association with ens synergistically regulates MT assembly. Together, these findings reveal novel features of Nin function and its regulation of a ncMTOC. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Interface-acting nucleotide controls polymerization dynamics at microtubule plus- and minus-ends

Play Episode Listen Later May 4, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.05.03.539131v1?rss=1 Authors: McCormick, L. A., Cleary, J. M., Hancock, W. O., Rice, L. M. Abstract: GTP-tubulin is preferentially incorporated at growing microtubule ends, but the biochemical mechanism by which the bound nucleotide regulates the strength of tubulin:tubulin interactions is debated. The "self-acting" (cis) model posits that the nucleotide (GTP or GDP) bound to a particular tubulin dictates how strongly that tubulin interacts, whereas the "interface-acting" (trans) model posits that the nucleotide at the interface of two tubulin dimers is the determinant. We identified a testable difference between these mechanisms using mixed nucleotide simulations of microtubule elongation: with self-acting nucleotide plus- and minus-end growth rates decreased in the same proportion to the amount of GDP-tubulin, whereas with interface-acting nucleotide plus-end growth rates decreased disproportionately. We then experimentally measured plus- and minus-end elongation rates in mixed nucleotides and observed a disproportionate effect of GDP-tubulin on plus-end growth rates. Simulations of microtubule growth were consistent with GDP-tubulin binding at and "poisoning" plus-ends but not at minus-ends. Quantitative agreement between simulations and experiments required nucleotide exchange at terminal plus-end subunits to mitigate the poisoning effect of GDP-tubulin there. Our results indicate that the interfacial nucleotide determines tubulin:tubulin interaction strength, thereby settling a longstanding debate over the effect of nucleotide state on microtubule dynamics. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Uncovering the multi-step process of stable microtubule bundle formation upon entry into quiescence

Play Episode Listen Later May 3, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.05.02.539064v1?rss=1 Authors: Laporte, D., Massoni-Laporte, A., LEfranc, C., Dompierre, J., Mauboules, D., Nsamba, E. T., Royou, A., Gal, L., Schuldiner, M., Gupta, M., Sagot, I. Abstract: Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Modification of the Neck Linker of KIF18A Alters Microtubule Subpopulation Preference

Play Episode Listen Later May 2, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.05.02.539080v1?rss=1 Authors: Queen, K. A., Cario, A., Berger, C. L., Stumpff, J. Abstract: Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Actin- and microtubule-based motors contribute to clathrin-independent endocytosis in yeast

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Play Episode Listen Later Apr 29, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.29.538819v1?rss=1 Authors: Woodard, T. K., Rioux, D. J., Prosser, D. C. Abstract: Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Target-identification and mechanism-of-action studies of indole terpenoid mimics reveal that proper spindle microtubule assembly is essential for Cdh1-mediated proteolysis of CENP-A

Play Episode Listen Later Apr 26, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.25.538200v1?rss=1 Authors: Peng, Y., Zhang, Y., Fang, R., Jiang, H., Lan, G., Liu, Y., Nie, Z., Zhang, S.-D., Ma, Y., Yang, P., Wang, F., Ge, H.-H., Zhang, W.-D., Luo, C., Li, A., He, W. Abstract: Centromere protein A (CENP-A) is a centromere-specific protein that determines kinetochore positioning and the accuracy of chromosome segregation. Despite its recognized importance in maintaining mitotic fidelity, the molecular details of CENP-A regulation in mitosis are still obscure. We performed a structure-activity relationship (SAR) study of the cell cycle-arresting indole terpenoid mimic JP18 and identified two more potent analogues, (+)-6-Br-JP18 and (+)-6-Cl-JP18. Tubulin was identified as a potential protein target of these two halogenated analogues by using the drug affinity responsive target stability (DARTS) based method. X-ray crystallographic analysis determined that (+)-6-Br-JP18 and (+)-6-Cl-JP18 bind to the colchicine-binding site of beta-tubulin. We further found that treatment of cancer cells with microtubule-targeting agents (MTAs), including these two compounds, upregulated CENP-A by destabilizing Cdh1, an E3 ubiquitin ligase component. The mechanistic study revealed that Cdh1 mediates proteolysis of CENP-A in mitosis, specifying the role of Cdh1 in maintaining mitotic fidelity. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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A mechanism that integrates microtubule motors of opposite polarity at the kinetochore corona

Play Episode Listen Later Apr 25, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.25.538277v1?rss=1 Authors: Cmentowski, V., D'Amico, E., Ciossani, G., Wohlgemuth, S., Owa, M., Dynlacht, B. D., Musacchio, A. Abstract: Chromosome biorientation on the mitotic spindle is prerequisite to errorless genome inheritance. CENP-E (kinesin 7) and Dynein-Dynactin (DD), microtubule motors with opposite polarity, promote biorientation from the kinetochore corona, a polymeric structure whose assembly requires MPS1 kinase. The corona building block consists of ROD, Zwilch, ZW10, and the DD adaptor Spindly (RZZS). How CENP-E and DD are scaffolded and mutually coordinated in the corona remains unclear. Here, we report near-complete depletion of RZZS and DD from kinetochores after depletion of CENP-E and the outer kinetochore protein KNL1. With inhibited MPS1, CENP-E, which we show binds directly to RZZS, is required to retain kinetochore RZZS. An RZZS phosphomimetic mutant bypasses this requirement. With active MPS1, CENP-E is dispensable for corona expansion, but strictly required for physiological kinetochore accumulation of DD. Thus, we identify the corona as an integrated scaffold where CENP-E kinesin controls DD kinetochore loading for coordinated bidirectional transport of chromosome cargo. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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ER structural remodeling requires TAK1/ATAT1-induced microtubule acetylation

Play Episode Listen Later Apr 21, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.20.537623v1?rss=1 Authors: Ortiz, H. R., Flores, P. C., Ramonett, A., Ahmed, T., Ellis, N. A., Langlais, P. R., Karthikeyan, M., Lee, N. Y. Abstract: Dynamic changes in the endoplasmic reticulum (ER) morphology are central to maintaining cellular homeostasis. Microtubules (MT) facilitate the continuous remodeling of the ER network into sheets and tubules by coordinating with many ER-shaping protein complexes, although how this process is controlled by extracellular signals remains unknown. Here we report that TAK1, a kinase responsive to numerous growth factors and cytokines including TGF-beta and TNF-alpha, triggers ER tubulation by activating aTAT1, an MT-acetylating enzyme that enhances ER-sliding. We show that this TAK1/aTAT-dependent ER remodeling promotes cell survival by actively downregulating BOK, an ER membrane-associated proapoptotic effector. While BOK is normally protected from degradation when complexed with IP3R, it is rapidly degraded upon their dissociation during the ER sheets-to-tubules conversion. These findings demonstrate a distinct mechanism of ligand-induced ER remodeling and suggest that the TAK1/aTAT pathway may be a key target in ER stress and dysfunction. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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mRNA Localization and Local Translation of the Microtubule Severing Enzyme, Fidgetin-Like 2, in Polarization, Migration and Outgrowth

Play Episode Listen Later Apr 17, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.17.537087v1?rss=1 Authors: Birnbaum, R., Biswas, J., Singer, R., Sharp, D. Abstract: Cell motility requires strict spatiotemporal control of protein expression. During cell migration, mRNA localization and local translation in subcellular areas like the leading edge and protrusions are particularly advantageous for regulating the reorganization of the cytoskeleton. Fidgetin-Like 2 (FL2), a microtubule severing enzyme (MSE) that restricts migration and outgrowth, localizes to the leading edge of protrusions where it severs dynamic microtubules. FL2 is primarily expressed during development but in adulthood, is spatially upregulated at the leading edge minutes after injury. Here, we show mRNA localization and local translation in protrusions of polarized cells are responsible for FL2 leading edge expression after injury. The data suggests that the RNA binding protein IMP1 is involved in the translational regulation and stabilization of FL2 mRNA, in competition with the miRNA let-7. These data exemplify the role of local translation in microtubule network reorganization during migration and elucidate an unexplored MSE protein localization mechanism. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Dual spatio-temporal regulation of axon growth and microtubule dynamics by RhoA signaling pathways

Play Episode Listen Later Apr 17, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.17.537156v1?rss=1 Authors: Wojnacki, J., Quassollo, G., Bordenave, M. D., Unsain, N., Martinez, G. F., Szalai, A. M., Pertz, O., Gundersen, G. G., Bartolini, F., Stefani, F. D., Caceres, A., Bisbal, M. Abstract: RhoA plays a crucial role in neuronal polarization, where its action restraining axon outgrowth has been thoroughly studied. We now report that RhoA has not only inhibitory but also a stimulatory effect on axon development depending on when and where exerts its action and the downstream effectors involved. In cultured hippocampal neurons, FRET imaging revealed that RhoA activity selectively localizes in growth cones of undifferentiated neurites, while in developing axons it displays a biphasic pattern, being low in nascent axons and high in elongating ones. RhoA-Rho kinase (ROCK) signaling prevents axon initiation but has no effect on elongation, while formin inhibition reduces axon extension without significantly altering initial outgrowth. Besides, RhoAmDia promotes axon elongation by stimulating growth cone microtubule stability and assembly, as opposed to RhoA-ROCK that restrains growth cone microtubule assembly and protrusion. Finally, we show that similar mechanisms might operate during axonal regeneration, with RhoAROCK slowing axon regrowth after axotomy and RhoA-mDia favoring extension of regenerated axons. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Determinants of cytoplasmic microtubule reorganization during ciliogenesis in Chlamydomonas reinhardtii

Play Episode Listen Later Apr 7, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.07.536038v1?rss=1 Authors: Dougherty, L. L., Avasthi, P. Abstract: At the core of cilia are microtubules which are important for establishing length and assisting ciliary assembly and disassembly; however, another role for microtubule regulation on ciliogenesis lies outside of the cilium. The microtubule cytoskeleton is a highly dynamic structure which reorganizes rapidly to assist in cellular processes. Cytoplasmic microtubule dynamics have previously been thought to be necessary to free up tubulin and proteins in the ciliary precursor pool for ciliogenesis. However, we previously found that low concentrations of taxol can stabilize cytoplasmic microtubules during deciliation while allowing normal cilium regrowth. Here we look at the relationship between ciliogenesis and cytoplasmic microtubule dynamics in Chlamydomonas reinhardtii using chemical and mechanical perturbations. We find that not only can stabilized cytoplasmic microtubules allow for normal ciliary assembly, but high calcium concentrations and low pH-induced deciliation cause microtubules to depolymerize separately from ciliary shedding. In addition, we find that through mechanical shearing, cilia regenerate more quickly despite intact cytoplasmic microtubules. Our data suggests that cytoplasmic microtubules are not a sink for a limiting pool of cytoplasmic tubulin, reorganization that occurs following deciliation is a consequence rather than a requirement for ciliogenesis, and intact microtubules in the cytoplasm and the proximal cilium support more efficient ciliary assembly. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Inhibition of microtubule detyrosination by parthenolide facilitates functional CNS axon regeneration

Play Episode Listen Later Apr 6, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.05.535722v1?rss=1 Authors: Leibinger, M., Zeitler, C., Paulat, M., Gobrecht, P., Hilla, A., Andreadaki, A., Guthoff, R., Fischer, D. Abstract: Injured axons in the central nervous system (CNS) usually fail to regenerate, causing permanent disabilities. However, the knockdown of PTEN or treatment of neurons with hyper-IL-6 (hIL-6) transforms neurons into a regenerative state, allowing them to regenerate axons in the injured optic nerve and spinal cord. Transneuronal delivery of hIL-6 to the injured brain stem neurons even enables functional recovery after severe spinal cord injury. Here we demonstrate that the beneficial hIL-6 and PTEN knockout effects on axon growth are limited by the induction of tubulin detyrosination in axonal growth cones. Hence, cotreatment with parthenolide, a compound blocking microtubule detyrosination, synergistically accelerates neurite growth of cultured murine and primary RGCs isolated from adult human eyes. Systemic application of the prodrug dimethylamino-parthenolide (DMAPT) enables axon regeneration in the injured optic nerve and spinal cord and accelerates hIL-6-mediated effects. Moreover, combinatorial treatment further improves locomotor recovery after severe SCI. Thus, DMAPT facilitates functional CNS regeneration and reduces the limiting effects of pro-regenerative treatments, making it a promising drug candidate for treating CNS injuries. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Ciliary protein CEP290 regulates focal adhesion via microtubule system in non-ciliated cells

Play Episode Listen Later Apr 3, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.02.535304v1?rss=1 Authors: Matsuo, K., Nakajima, Y., Shigeta, M., Kobayashi, D., Sakaki, S., Inoue, S., Takeshita, N., Ueyama, A., Nishikawa, K., Saba, R., Yokoyama, T., Yashiro, K. Abstract: Almost all differentiated mammalian cells have primary cilia on their surface. Ciliary dysfunction causes ciliopathy in humans. Centrosomal protein 290 (CEP290) is a ciliary protein that causes ciliopathies, localizes at the cilial base in ciliated cells, whereas it localizes to the centrosome in non-ciliated proliferating cells. The cilia-dependent function of CEP290 has been extensively studied; however, the cilia-independent function, which is likely responsible for the wider phenotypic spectra of CEP290-related ciliopathies, remains largely unknown. Here, we examined cilia-independent functions of CEP290 in non-ciliated cells. Our study showed that Cep290 function loss suppresses microtubule elongation due to microtubule organizing center malfunction. Surprisingly, CEP290 forms a complex with the adenomatous polyposis coli (APC) protein encoded by the adenomatous polyposis coli gene. The APC-CEP290 complex exists in the centrosome and on microtubule fibers. Notably, the reduced focal adhesion formation is likely responsible for the Cep290 mutant phenotypes, including impaired directed cell migration, shrunken cell shape, and reduced adhesive capacity to the extracellular matrix. The APC-CEP290 complex is consistently important for transporting a focal adhesion molecule, paxillin, to focal adhesions in non-ciliated cells. Thus, our findings provide a novel platform to better understand the ciliopathies. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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CryoET shows cofilactin filaments inside the microtubule lumen

Play Episode Listen Later Mar 31, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.03.31.535077v1?rss=1 Authors: Santos, C., Rogers, S. L., Carter, A. P. Abstract: Cytoplasmic microtubules are tubular polymers that can harbor small proteins or filaments inside their lumen. The identity of these objects and what causes their accumulation has not been conclusively established. Here, we used cryogenic electron tomography (cryoET) of Drosophila S2 cell protrusions and found filaments inside the microtubule lumen, which resemble those reported recently in human HAP1 cells. The frequency of these filaments increased upon inhibition of the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) with the small-molecule drug thapsigargin. Subtomogram averaging showed that the luminal filaments adopt a helical structure reminiscent of cofilin-bound actin (cofilactin). Consistent with this, cofilin was activated in cells under the same conditions that increased luminal filament occurrence. Furthermore, RNAi knock-down of cofilin reduced the frequency of luminal filaments with cofilactin morphology. These results suggest that cofilin activation stimulates its accumulation on actin filaments inside the microtubule lumen. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Actin-microtubule crosstalk imparts stiffness to the contractile ring in fission yeast.

Play Episode Listen Later Mar 2, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.03.01.530611v1?rss=1 Authors: Bellingham-Johnstun, K., Tyree, Z. L., Martinez-Baird, J., Thorn, A., Laplante, C. Abstract: Actin-microtubule interactions are critical for cell division yet how these networks of polymers mutually influence their mechanical properties and functions in live cells remains unknown. In fission yeast, the post-anaphase array (PAA) of microtubules assembles in the plane of the contractile ring and its assembly relies on the Myp2p-dependent recruitment of Mto1p, a component of equatorial microtubule organizing centers (eMTOCs). The general organization of this array of microtubule and the impact on their physical attachment to the contractile ring remain unclear. We found that Myp2p facilitates the recruitment of Mto1p to the inner face of the contractile ring where the eMTOCs polymerize microtubules without their direct interaction. The PAA microtubules form a dynamic polygon of Ase1p crosslinked microtubules inside the contractile ring. The specific loss of PAA microtubules affects the mechanical properties of the contractile ring of actin by lowering its stiffness. This change in the mechanical properties of the ring has no measurable impact on cytokinesis or on the anchoring of the ring. Our work proposes that the PAA microtubules exploit the contractile ring for their assembly and function during cell division while the contractile ring may receive no benefit from these interactions. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Local microtubule and F-actin distributions fully determine the spatial geometry of Drosophila sensory dendritic arbors

local llc determine copy cox sensory spatial geometry distributions morphology drosophila actin biorxiv dendritic microtubule

Play Episode Listen Later Feb 27, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.24.529978v1?rss=1 Authors: Nanda, S., Bhattacharjee, S., Cox, D. N., Ascoli, G. A. Abstract: Dendritic morphology underlies the source and processing of neuronal signal inputs. Morphology can be broadly described by two types of geometric characteristics. The first is dendrogram topology, defined by the length and frequency of the arbor branches; the second is spatial embedding, mainly determined by branch angles and tortuosity. We have previously demonstrated that microtubules and actin filaments are associated with arbor elongation and branching, fully constraining dendrogram topology. Here we relate the local distribution of these two primary cytoskeletal components with dendritic spatial embedding. We first reconstruct and analyze 167 sensory neurons from the Drosophila larva encompassing multiple cell classes and genotypes. We observe that branches with higher microtubule concentration are overall straighter and tend to deviate less from the direction of their parent branch. F-actin displays a similar effect on the angular deviation from the parent branch direction, but its influence on branch tortuosity varies by class and genotype. We then create a computational model of dendritic morphology purely constrained by the cytoskeletal composition imaged from real neurons. The model quantitatively captures both spatial embedding and dendrogram topology across all tested neuron groups. These results suggest a common developmental mechanism regulating diverse morphologies, where the local cytoskeletal distribution can fully specify the overall emergent geometry of dendritic arbors. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

MAP9/MAPH-9 supports axonemal microtubule doublets and modulates motor movement

Play Episode Listen Later Feb 23, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.23.529616v1?rss=1 Authors: Tran, M. V., Ferguson, J. W., Cote, L. E., Khuntsariya, D., Fetter, R. D., Wang, J. T., Wellard, S. R., Sallee, M. D., Eskinazi, S., Genova, M., Magiera, M. M., Janke, C., Stearns, T., Lansky, Z., Shen, K., Magescas, J., Feldman, J. L. Abstract: Microtubule doublets (MTDs) are a well conserved compound microtubule structure found primarily in cilia. However, the mechanisms by which MTDs form and are maintained in vivo remain poorly understood. Here, we characterize microtubule-associated protein 9 (MAP9) as a novel MTD-associated protein. We demonstrate that C. elegans MAPH-9, a MAP9 homolog, is present during MTD assembly and localizes exclusively to MTDs, a preference that is in part mediated by tubulin polyglutamylation. Loss of MAPH-9 caused ultrastructural MTD defects, dysregulated axonemal motor velocity, and perturbed cilia function. As we found that the mammalian ortholog MAP9 localized to axonemes in cultured mammalian cells and mouse tissues, we propose that MAP9/MAPH-9 plays a conserved role in supporting the structure of axonemal MTDs and regulating ciliary motors. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

loss movement llc copy ferguson motor wang feldman cote shen genova stearns fetter lansky janke mtd biorxiv wellard microtubule maph mtds

Tau-Tubulin Kinase 2 restrains microtubule-depolymerizer KIF2A to support primary cilia growth.

Play Episode Listen Later Feb 21, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.21.529351v1?rss=1 Authors: Vyslouzil, D., Bernatik, O., Renzova, T., Bino, L., Lacigova, A., Cajanek, L. Abstract: The initiation of assembly of primary cilia, organelles with crucial functions in development and disease, is under the control of Tau-Tubulin Kinase 2 (TTBK2). Recent work has implicated TTBK2 also in the regulation of primary cilia maintenance and function. However, the mechanisms underlying individual functions of TTBK2 in primary cilia are not fully understood. Here, to dissect the role of TTBK2 in primary cilia maintenance in human cells, we examined disease related TTBK2 truncations. We demonstrate that these truncated protein moieties show selective activity towards TTBK2 substrates. This creates a semi-permissive condition where partial TTBK2 activity suffices to support the initiation of ciliogenesis but fails to sustain primary cilia length. Subsequently, we show that the defects in primary cilia growth are linked to aberrant turnover of kinesin KIF2A at basal body. Furthermore, we demonstrate that TTBK2 regulates KIF2A by phosphorylation, which in turn restrains its levels at the ciliary base to promote primary cilia elongation and maintenance. Taken together, our data highlight the regulation of KIF2A by TTBK2 as an important mechanism governing primary cilia in human cells. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

growth llc primary copy subsequently bino cilia kinase biorxiv microtubule tubulin

Microtubule binding of the human HAUS complex is directly controlled by importins and Ran-GTP

Play Episode Listen Later Feb 20, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.19.529112v1?rss=1 Authors: Ustinova, K., Ruhnow, F., Gili, M., Surrey, T. Abstract: Mitotic spindle assembly during cell division is a highly regulated process. Ran-GTP produced around chromosomes controls the activity of a multitude of spindle assembly factors by releasing them from inhibitory interaction with importins. A major consequence of Ran-GTP regulation is the stimulation of local microtubule nucleation around chromosomes via augmin/HAUS-mediated branched microtubule nucleation, a process that is critically important for correct spindle assembly. However, augmin is not known to be a direct target of the Ran-GTP pathway, raising the question of how its activity is controlled. Here we present the in vitro reconstitution of Ran-GTP-regulated microtubule binding of the human HAUS complex. We demonstrate that importins directly bind to the HAUS complex, which prevents HAUS from binding to microtubules. Ran-GTP relieves this inhibition. Therefore, the HAUS complex is a direct target of the Ran-GTP pathway, suggesting that branching microtubule nucleation is directly regulated by the Ran-GTP gradient around chromosomes in dividing cells. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Vimentin impacts centrosome function and microtubule acetylation

influencers autism moonlight regulators chromatin microtubule

Play Episode Listen Later Feb 18, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.17.528977v1?rss=1 Authors: Saldanha, R., Tri Ho Thanh, M., Krishnan, N., Hehnly, H., Patteson, A. E. Abstract: Cell polarity is important for controlling cell shape, motility, and cell division processes. Vimentin intermediate filaments are necessary for proper polarization of migrating fibroblasts and assembly of vimentin and microtubule networks is dynamically coordinated, but the precise details of how vimentin mediates cell polarity remain unclear. Here, we characterize the effects of vimentin on the structure and microtubule-nucleating activity of the cell centrosome and the dynamics of the microtubule network in wild-type and vimentin-null mouse embryonic fibroblasts (mEFs). We find that vimentin mediates the structure of the pericentrosomal material, promotes centrosome-mediated microtubule regrowth, and increases the level of stable acetylated microtubules in the cell. Our results suggest that vimentin modulates centrosome structure and function as well as microtubule network stability, which has importantimplications for how cells establish proper cell polarization and persistent migration. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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Autism-linked chromatin regulators may moonlight as microtubule influencers

Spectrum Autism Research

Play Episode Listen Later Feb 8, 2023 4:33

Five autism-linked genes widely known as chromatin regulators appear to also shape the cell's internal skeleton.

Autism-linked chromatin regulators may moonlight as microtubule influencers

Spectrum Autism Research

Play Episode Listen Later Feb 8, 2023 4:33

Five autism-linked genes widely known as chromatin regulators appear to also shape the cell's internal skeleton.

influencers autism moonlight regulators chromatin microtubule

Microtubule competition and cell growth recenter the nucleus after anaphase in fission yeast.

Play Episode Listen Later Feb 1, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.01.31.526443v1?rss=1 Authors: Bellingham-Johnstun, K., Thorn, A., Belmonte, J. M., Laplante, C. Abstract: Cells actively position their nucleus based on their activity. In fission yeast, microtubule-dependent nuclear centering is critical for symmetrical cell division. After spindle disassembly at the end of anaphase, the nucleus recenters over a ~90 min period, approximately half of the duration of the cell cycle. Live cell and simulation experiments support the cooperation of two distinct mechanisms in the slow recentering of the nucleus. First, a push-push mechanism acts from spindle disassembly to septation and involves the opposing actions of the mitotic Spindle Pole Body microtubules that push the nucleus away from the ends of the cell while post-anaphase array of microtubules basket the nucleus and limit its migration toward the division plane. Second, a slow-and-grow mechanism finalizes nuclear centering in the newborn cell. In this mechanism, microtubule competition stalls the nucleus while asymmetric cell growth slowly centers it. Our work underlines how intrinsic properties of microtubules differently impact nuclear positioning according to microtubule network organization and cell size. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

live growth competition llc copy thorn yeast nucleus belmonte fission laplante recenter biorxiv microtubule anaphase

Caltubin regulates microtubule stability via Ca2+-dependent mechanisms favouring neurite regrowth

Play Episode Listen Later Jan 23, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.01.23.525163v1?rss=1 Authors: Barszczyk, A., Bandura, J., Zhang, Q., Wang, H., Deurloo, M., Ahmed, Y., Dong, A., Meister, P., Lee, J., Sun, H.-S., Tong, Y., Feng, Z.-P. Abstract: Microtubule regulation is highly controlled in nerve regeneration. Caltubin, a novel Lymnaea stagnalis protein, contains putative EF-hand calcium-binding motifs and promotes neuronal outgrowth in Lymnaea and mouse. Here, we generated cell-permeable caltubin proteins to investigate mechanisms underlying this effect. We observed increased neurite extension and outgrowth following injury in caltubin-treated mouse neurons compared to vehicle controls. Purified caltubin bound -tubulin between its L391-V405 amino acids and promoted microtubule assembly. Caltubin competitively inhibited binding of tubulin tyrosine ligase, which catalyzes tubulin retyrosination, and increased the ratio of detyrosinated to tyrosinated tubulin. Our crystal structure analysis confirmed that caltubin has four Ca2+-binding EF-hand motifs, like calmodulin but has distinct peptide binding domains. Our work suggests a unique Ca2+-dependent regulatory mechanism of microtubule assembly by caltubin. This may represent an essential mechanism of axonal regulation, which may optimize its activity in response to various calcium states, both physiological and following injury. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

sun llc copy stability wang meister dongs zhang dependent ef mechanisms tong feng purified regulates bandura biorxiv regrowth ca2 favouring microtubule

Microtubule decay is a driver of neuronal ageing and a promising target for intervention

Play Episode Listen Later Jan 13, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.01.11.523590v1?rss=1 Authors: Okenve-Ramos, P., Gosling, R., Chojnowska-Monga, M., Gupta, K., Shields, S., Sanchez-Soriano, N. Abstract: Natural ageing is accompanied by a decline in motor, sensory and cognitive functions, all impacting life quality. Ageing is the predominant risk factor for many neurodegenerative diseases, including Parkinson's and Alzheimer's disease. We need therefore to gain a better understanding of the cellular and physiological processes underlying age-related neuronal decay. However, gaining this understanding is a slow process due to the long time required to age mammalian or vertebrate model animals. Here we introduce a new cellular model within the Drosophila brain where neurons show typical ageing hallmarks known from the primate brain, including axonal swellings, cytoskeletal decay, a reduction in axonal calibre and morphological changes arising at synaptic terminals. In the fly brain, these changes occur within just a few weeks, ideal to study the underlying mechanisms. We observe that decay of the neuronal microtubule cytoskeleton clearly precedes other ageing hallmarks. We show that the microtubule-binding factors Tau, EB1 and Shot, are necessary for microtubule maintenance in axons and synapses. Their functional loss during ageing triggers microtubule bundle decay followed by the decline in axons and synapses. Genetic manipulations that improve microtubule networks, slow down other neuronal ageing hallmarks and confer aged specimens with the ability to outperform age-matched controls. Our work suggests therefore that microtubule networks are a key lesion site in ageing neurons and offer promising opportunities to improve neuronal decay in advanced age. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

target llc alzheimer's disease driver parkinson copy intervention shot genetic promising gupta shields decay ageing tau gosling drosophila neuronal biorxiv eb1 microtubule

Genome wide-analysis of anterior-posterior mRNA localization in Stentor coeruleus reveals a role for the microtubule cytoskeleton

Play Episode Listen Later Jan 10, 2023

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.01.09.523364v1?rss=1 Authors: Albright, A. R., Angeles-Albores, D., Marshall, W. F. Abstract: Cells have complex and beautiful structures that are important for their function, but understanding the molecular mechanisms that produce these structures is a challenging problem due to the gap in size scales between molecular interactions and cellular structures. The giant ciliate Stentor coeruleus is a unicellular model organism whose large size, reproducible structure, and ability to heal wounds and regenerate has historically allowed the formation of structure in a single cell to be addressed using methods of experimental embryology. Such studies have shown that specific cellular structures, such as the oral apparatus, always form in specific regions of the cell, which raises the question of what is the source of positional information within this organism? By analogy with embryonic development, in which localized mRNA is often used to mark position, we asked whether position along the anterior-posterior axis of Stentor might be marked by specific regionalized mRNAs. By physically bisecting cells and using single-cell RNAseq analysis on each half, we were able to identify sets of messages enriched in either the anterior or posterior half. We repeated this analysis in cells in which a set of longitudinal microtubule bundles running down the whole length of the cell, known as KM-fibers, were disrupted by RNAi of beta tubulin. We found that many messages either lost their regionalized distribution , or else switched to an opposite distribution, such that anterior-enriched messages in control became posterior-enriched in the RNAi cells, or vice versa. This study indicates that mRNA can be regionalized within a single giant cell, and that microtubules may play a role, possibly by serving as tracks for movement of the messages. This study also illustrates a strategy for subcellular spatial genomics based on physical dissection, allowing the high throughput and sensitivity of sequencing technology to be brought to bear as a rapid, low cost alternative to current fluorescence imaging based methods. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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CLASPs stabilize the intermediate state between microtubule growth and catastrophe

growth llc copy catastrophe conversely stabilize chatterjee gtp intermediate state biorxiv microtubule

Play Episode Listen Later Dec 4, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.12.03.518990v1?rss=1 Authors: Lawrence, E. J., Chatterjee, S., Zanic, M. Abstract: CLASPs regulate microtubules in many fundamental cellular processes. CLASPs stabilize dynamic microtubules by suppressing catastrophe and promoting rescue, the switch-like transitions between microtubule growth and shrinkage. However, the molecular mechanisms underlying CLASPs activity are not understood. Here, we investigate the effects of CLASPs on distinct microtubule substrates in the absence of tubulin to gain insight into how CLASPs regulate microtubule dynamics. Surprisingly, we find that human CLASP1 depolymerizes stable microtubules in the presence of GTP, but not in the absence of nucleotide. Conversely, CLASP1 stabilizes dynamic microtubules upon tubulin dilution in the presence of GTP. Our results demonstrate that CLASP1 drives microtubule substrates with different inherent stabilities into the same slowly-depolymerizing state in the absence of tubulin in a nucleotide-dependent manner. We interpret this state as the pre-catastrophe intermediate state between microtubule growth and shrinkage. Thus, we conclude that CLASPs stabilize the intermediate state between microtubule growth and shrinkage to suppress microtubule catastrophe and promote rescue. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Running Kinesin-1 shapes the microtubule acetylation gradient

Play Episode Listen Later Dec 2, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.12.01.518806v1?rss=1 Authors: Andreu-Carbo, M., Egoldt, C., Velluz, M.-C., Aumeier, C. Abstract: The properties of single microtubules within the microtubule network can be modulated through posttranslational modifications (PTMs), including acetylation within the lumen of microtubules. To access the lumen, the enzymes could either enter through the microtubule ends or at damage sites along the microtubule shaft. Here we show that the acetylation profile depends on damage sites, which can be caused by the motor protein kinesin-1. Indeed, the entry of the deacetylase HDAC6 into the microtubule lumen depends on kinesin-1-induced damage sites. In contrast, activity of the microtubule acetylase TAT1 is independent of kinesin-1 and shaft damage. On a cellular level, our results show that microtubule acetylation distributes in an exponential gradient. This gradient results from tight regulation of microtubule (de-)acetylation and scales with the size of the cells. The control of shaft damage represents a novel mechanism to regulate PTM inside the microtubule by giving access to the lumen. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

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A hydrogel-based model of aortic stiffness reveals that microtubules are novel regulators of smooth muscle cell hypertrophy

model llc morris muscle compliance copy smooth conversely regulators conclusions hypertrophy stiffness aortic hydrogel biorxiv microtubules microtubule

Play Episode Listen Later Nov 25, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.23.517637v1?rss=1 Authors: Johnson, R. T., Ahmed, S., Wostear, F., Morris, C. J., Warren, D. T. Abstract: Background and Purpose: Decreased aortic compliance is a precursor to numerous cardiovascular diseases. Compliance is regulated by the stiffness of the aortic wall and the vascular smooth muscle cells (VSMCs) within it. During ageing, the extracellular matrix of the aortic wall stiffens, reducing compliance and leading to conditions such as hypertension. In response, VSMCs generate enhanced contractile forces and undergo hypertrophy, promoting VSMC stiffening and further reducing compliance. Due to a lack of suitable in vitro models, the mechanisms driving VSMC hypertrophy in response to matrix stiffness remain poorly defined. Experimental Approach: Human VSMCs were seeded onto polyacrylamide hydrogels whose stiffness mimicked either healthy or aged/diseased aortae. VSMC response to contractile agonist stimulation was measured through changes in cell area and volume. VSMCs were pre-treated with pharmacological agents prior to agonist stimulation to identify regulators of VSMC contractility and hypertrophy. Key Results: VSMCs undergo a differential response to contractile agonist stimulation based on matrix stiffness. On pliable hydrogels, VSMCs contract, decreasing in cell area whereas on rigid hydrogels, VSMCs undergo a hypertrophic response, increasing in area and volume. Microtubule stabilisation prevented hypertrophy whilst leaving VSMC contraction on pliable hydrogels unimpeded. Conversely, microtubule destabilisation inhibited contraction and induced hypertrophy within VSMCs on pliable hydrogels. Conclusions and Implications: In response to enhanced matrix rigidity, VSMC undergo a hypertrophic response as result of decreased microtubule stability. Using standard biological techniques and equipment, we present a screening assay capable of identifying novel regulators of matrix rigidity induced VSMC hypertrophy. This assay can identify both beneficial and deleterious effects of pharmacological agents to cardiovascular health. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Calaxin stabilizes the docking of outer arm dyneins onto ciliary doublet microtubule in vertebrates

Play Episode Listen Later Nov 12, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.10.516068v1?rss=1 Authors: Yamaguchi, H., Morikawa, M., Kikkawa, M. Abstract: Outer arm dynein (OAD) is the main force generator of ciliary beating. Although OAD loss is the most frequent cause of human primary ciliary dyskinesia, the docking mechanism of OAD onto the ciliary doublet microtubule (DMT) remains elusive in vertebrates. Here, we analyzed the functions of Calaxin/Efcab1 and Armc4, the components of vertebrate OAD-DC (docking complex), using zebrafish spermatozoa and cryo-electron tomography. Mutation of armc4 caused complete loss of OAD, whereas mutation of calaxin caused only partial loss of OAD. Detailed structural analysis revealed that calaxin-/- OADs are tethered to DMT through DC components other than Calaxin, and that recombinant Calaxin can autonomously rescue the deficient DC structure and the OAD instability. Our data demonstrate the discrete roles of Calaxin and Armc4 in the OAD-DMT interaction, suggesting the stabilizing process of OAD docking onto DMT in vertebrates. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

dc llc copy detailed outer dmt mutation docking morikawa vertebrates double t biorxiv oad microtubule

Microtubule binding-induced allostery promotes LIS1 dissociation from dynein prior to cargo transport

Play Episode Listen Later Nov 8, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.08.515461v1?rss=1 Authors: Ton, W. D., Wang, Y., Chai, P., Beauchamp-Perez, C., Flint, N. T., Lammers, L. G., Xiong, H., Zhang, K., Markus, S. M. Abstract: The lissencephaly-related protein LIS1 is a critical regulator of cytoplasmic dynein that governs motor function and intracellular localization (e.g., to microtubule plus-ends). Although LIS1 binding is required for dynein activity, its unbinding prior to initiation of cargo transport is equally important, since preventing dissociation leads to dynein dysfunction. To understand whether and how dynein-LIS1 binding is modulated, we engineered dynein mutants locked in a microtubule-bound (MT-B) or -unbound (MT-U) state. Whereas the MT-B mutant exhibits low LIS1 affinity, the MT-U mutant binds LIS1 with high affinity, and as a consequence remains almost irreversibly bound to microtubule plus-ends. We find that a monomeric motor domain is sufficient to exhibit these opposing LIS1 affinities, and that this is an evolutionarily conserved phenomenon. Three cryo-EM structures of dynein with and without LIS1 reveal microtubule-binding induced conformational changes responsible for this regulation. Our work reveals key biochemical and structural insight into LIS1-mediated dynein activation. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

llc copy transport wang flint cargo zhang binding chai induced promotes dissociation lammers biorxiv microtubule

Oocytes can repair DNA damage during meiosis via a microtubule-dependent recruitment of CIP2A-MDC1-TOPBP1 complex from spindle pole to chromosomes

Play Episode Listen Later Nov 4, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.04.514992v1?rss=1 Authors: Leem, J., Kim, J.-S., Oh, J. S. Abstract: Because DNA double-strand breaks (DSBs) greatly threaten genomic integrity, effective DNA damage sensing and repair are essential for cellular survival in all organisms. However, DSB repair mainly occurs during the interphase and is repressed during mitosis. Here, we show that, unlike mitotic cells, oocytes can repair DSBs during meiosis through microtubule-dependent chromosomal recruitment of the CIP2A-MDC1-TOPBP1 complex from spindle poles. After DSB induction, we observed spindle shrinkage and stabilization, as well as BRCA1 and 53BP1 recruitment to chromosomes and subsequent DSB repair during meiosis I. Moreover, p-MDC1 and p-TOPBP1 were recruited from spindle poles to chromosomes in a CIP2A-dependent manner. This pole-to-chromosome relocation of the CIP2A-MDC1-TOPBP1 complex was impaired not only by depolymerizing microtubules but also by depleting CENP-A or HEC1, indicating that the kinetochore/centromere serves as a structural hub for microtubule-dependent transport of the CIP2A-MDC1-TOPBP1 complex. Mechanistically, DSB-induced CIP2A-MDC1-TOPBP1 relocation is regulated by PLK1 but not by ATM activity. Our data provide new insights into the critical crosstalk between chromosomes and spindle microtubules in response to DNA damage to maintain genomic stability during oocyte meiosis. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

dna llc complex copy repair recruitment pole atm dependent chromosomes brca1 spindle dsb biorxiv dna damage meiosis microtubule dsbs oocytes plk1

Quantitative live cell imaging of a tauopathy model enables the identification of a polypharmacological drug candidate that restores physiological microtubule regulation

Play Episode Listen Later Nov 1, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.31.514565v1?rss=1 Authors: Pinzi, L., Conze, C., Bisi, N., Torre, G. D., Monteiro-Abreu, N., Trushina, N. I., Soliman, A., Krusenbaum, A., Dolouei, M. K., Hellwig, A., Christodoulou, M. S., Passarella, D., Bakota, L., Rastelli, G., Brandt, R. Abstract: Tauopathies such as Alzheimers disease are characterized by the aggregation and increased phosphorylation of the microtubule-associated protein tau. The pathological changes in tau are closely linked to neurodegeneration, making tau a prime candidate for intervention. However, the multiple facets of tau function and the lack of cellular tauopathy models that could support mechanism-based drug development hampers progress. Here we report the development of a live-cell imaging approach to quantitatively monitor pathological changes of human tau as it interacts with axonal microtubules. We show that a full-length aggregation-prone tau construct exhibits reduced interaction with microtubules as it increasingly aggregates. Through chemoinformatic analyses, we identified 2-phenyloxazole (PHOX) derivatives as putative polypharmacological small molecules that inhibit tau aggregation and modulate tau phosphorylation. We found that PHOX15 restores the physiological microtubule interaction of aggregation-prone tau in neurons and inhibits the first phase of tau aggregation in vitro. Furthermore, we report that PHOX15 inhibits the tau kinases GSK3beta and Cdk5, alters the kinome activity of model neurons, and reduces tau phosphorylation at disease-relevant sites. Molecular dynamics simulations highlight cryptic channel-like pockets crossing tau protofilaments and indicate that the binding of PHOX15 in one of the channels reduces the protofilaments ability to adopt a PHF-like conformation. The data show that our imaging approach provides a useful tool for identifying compounds that modulate tau-microtubule interaction in axons. We demonstrate that a polypharmacological approach to simultaneously treat tau aggregation and tau phosphorylation is able to restore physiological microtubule regulation, identifying PHOX15 as a promising drug candidate to counteract tau-induced neurodegeneration. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Extracellular matrix stiffness regulates fibroblast differentiation by influencing DNA methyltransferase 1 expression through microtubule polymerization

Play Episode Listen Later Oct 20, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.20.513009v1?rss=1 Authors: Zhao, Z., Hong, L., Huang, G., He, Y., Zuo, X., Han, W. Abstract: Cells sense physical cues, such as changes in extracellular matrix (ECM) stiffness, and translate these stimuli into biochemical signals that control various aspects of cellular behavior, thereby facilitating physiological and pathological processes in various organs. Evidence from multiple studies suggests that the anterior vaginal wall stiffness is higher in POP patients than in non-POP patients. Our experiments found that the expression of -smooth muscle actin (-SMA) in the anterior vaginal wall of patients with POP was increased, and the expression of DNMT1 was decreased. We used polyacrylamide gel to simulate matrix stiffening in vitro, and substrate stiffening induced the high expression of myofibroblast markers -SMA and CTGF in L929 cells. Inhibition of DNMT1 promotes fibroblast differentiation into myofibroblasts in vitro. The results of bioinformatics analysis showed that the expression of DNMT1 was significantly correlated with microtubule polymerization-related proteins. The experiment showed that the microtubule polymerization inhibitor nocodazole could eliminate the decrease of DNMT1 expression in fibroblasts induced by high stiffness. We conclude that fibroblasts sense an increase in the stiffness of the surrounding matrix and regulate fibroblast differentiation by regulating the expression of DNA methyltransferase 1 (DNMT1) through the regulation of microtubule polymerization. This study may help to elucidate the complex crosstalk between vaginal fibroblasts and their surrounding matrix in both healthy and pathological conditions, and provide new insights into the implications of potentially targeted phenotypic regulation mechanisms in material-related therapeutic applications. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

dna pop llc matrix copy expression influencing hong huang differentiation sma ecm inhibition stiffness regulates biorxiv extracellular fibroblast polymerization microtubule methyltransferase dnmt1 ctgf

Centrosome amplification fine-tunes tubulin acetylation to differentially control intracellular organization

Consciousness Is All There Is

Play Episode Listen Later Oct 17, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.17.512471v1?rss=1 Authors: Godinho, S. A., Monteiro, P., Yeon, B., Wallis, S. S. Abstract: Intracellular organelle organisation is conserved in eukaryotic cells and is primarily achieved through active transport by motor proteins along the microtubule cytoskeleton. Microtubule posttranslational modifications (PTMs) contribute to microtubule diversity and differentially regulate motor-mediated transport. Here we show that centrosome amplification induces a global change in organelle positioning towards the cell periphery and facilitates nuclear migration through confined spaces. This reorganisation requires kinesin-1 and is analogous to loss of dynein. Cells with amplified centrosomes display increased levels of acetylated tubulin, a PTM known to enhance kinesin-1 mediated transport. Depletion of -tubulin acetyltransferase 1 (TAT1) to block tubulin acetylation, which has no impact on control cells, rescues the displacement of centrosomes, mitochondria and vimentin, but not Golgi or endosomes. Analyses of the distribution of acetylated microtubules indicates that the polarisation of modified microtubules, rather than levels alone, plays an important role in organelle positioning. We propose that tubulin acetylation differentially impacts kinesin-1-mediated organelle displacement, suggesting that each organelle must have its own sensing and response mechanisms to ensure fine-tuning of its distribution in cells. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

llc copy tunes cells monteiro analyses amplification depletion yeon ptm intracellular biorxiv golgi microtubule differentially ptms tubulin

Quantum Vibration, Sound Frequency, and Cognition with Dr. Anirban Bandyopadhyay - Part 2

Play Episode Listen Later Sep 26, 2022 43:21

In this interview, Dr. Nader sits down with Dr. Anirban Bandyopadhyay to discuss the nature of consciousness and microtubule vibrations. From Dr. Bandyopadhyay's perspective, treating the brain with microtubule vibrations could benefit a host of mental, neurological, and cognitive conditions. Microtubule quantum vibrations appear to interfere and produce much slower EEG "beat frequencies" says Dr. Bandyopadhyay, and despite a century of clinical use the underlying origins of EEG rhythms have remained a mystery. Dr. Bandyopadhyay is a Senior Researcher at the National Institute for Materials Science in Tsukuba, Japan. He possesses a Masters of Science in Condensed Matter Physics, Computer, Numerical Analysis, and Astrophysics from North Bengal University, as well as a PhD in Physics from Jadavpur University, where he worked on supramolecular electronics and multi-level switching. Make sure to listen to Part 1! Dr Bandyopadhyay | LinkedIn https://jp.linkedin.com/in/anirbanbandyopadhyay Dr Tony Nader | Instagram http://instagram.com/drtonynader Dr Tony Nader | Twitter http://twitter.com/drtonynader Dr Tony Nader | YouTube https://www.youtube.com/user/DrTonyNader Dr Tony Nader | Facebook http://facebook.com/DrTonyNader

science japan sound phd masters computers physics quantum national institutes frequency vibration cognition astrophysics eeg nader senior researcher materials science tsukuba anirban microtubule jadavpur university numerical analysis

Quantum Vibration, Sound Frequency, And Cognition With Dr. Anirban Bandyopadhyay - Part 1

Consciousness Is All There Is

Play Episode Listen Later Sep 12, 2022 30:58

In this interview, Dr. Nader sits down with Dr. Anirban Bandyopadhyay to discuss the nature of consciousness and microtubule vibrations. From Dr. Bandyopadhyay's perspective, treating the brain with microtubule vibrations could benefit a host of mental, neurological, and cognitive conditions. Microtubule quantum vibrations appear to interfere and produce much slower EEG "beat frequencies" says Dr. Bandyopadhyay, and despite a century of clinical use the underlying origins of EEG rhythms have remained a mystery. Dr. Bandyopadhyay is a Senior Researcher at the National Institute for Materials Science in Tsukuba, Japan. He possesses a Masters of Science in Condensed Matter Physics, Computer, Numerical Analysis, and Astrophysics from North Bengal University, as well as a PhD in Physics from Jadavpur University, where he worked on supramolecular electronics and multi-level switching. Part 2 Coming Soon! Dr Anirban | LinkedIn https://jp.linkedin.com/in/anirbanbandyopadhyay Dr Tony Nader | Instagram http://instagram.com/drtonynader Dr Tony Nader | Twitter http://twitter.com/drtonynader Dr Tony Nader | YouTube https://www.youtube.com/user/DrTonyNader Dr Tony Nader | Facebook http://facebook.com/DrTonyNader

science japan sound phd masters computers coming soon physics quantum national institutes frequency vibration cognition astrophysics eeg nader senior researcher materials science tsukuba anirban microtubule jadavpur university numerical analysis

Musleblind-1 regulates microtubule cytoskeleton in C. elegans mechanosensory neuron through tubulin mRNAs

The Medbullets Step 1 Podcast

Play Episode Listen Later Sep 8, 2022

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.09.07.506915v1?rss=1 Authors: Puri, D., Samaddar, S., Banerjee, S., Ghosh-Roy, A. Abstract: Regulation of microtubule cytoskeleton is fundamental for the development and maintenance of neuronal architecture. Recent studies have shown that regulated RNA processing is also critical for the establishment and maintenance of neural circuits. In a genetic screen using mechanosensory neurons of C. elegans, we identified a mutation in muscleblind-1 as a suppressor of loss of kinesin-13 family microtubule destabilizing factor klp-7. Muscleblind-1(MBL-1) is an RNA-binding protein that regulates the splicing, localization, and stability of RNA. We found that mbl-1 is required cell-autonomously for axon growth and synapse formation in the posterior lateral microtubule (PLM) neuron. Loss of mbl-1 affects stability and plus-end-out organization of microtubules in the anterior process of PLM. These defects are also accompanied by abnormal axonal transport of the synaptic protein RAB-3 and loss of gentle touch sensation in mbl-1 mutant. Our data showed that mbl-1 is genetically epistatic to mec-7 ({beta}-tubulin) and mec-12 (-tubulin) for axon growth. The immunoprecipitation of MBL-1 pulls down the mec-7, mec-12, and sad-1 mRNAs. Additionally, the mbl-1 mutants show a reduction in the level and stability of mec-7 and mec-12 transcripts. Independently, mbl-1 is epistatic to sad-1 for synapse formation. Our work elucidated a previously unknown link between RNA binding protein and cytoskeletal machinery for the development and maintenance of the nervous system. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

loss copy rna independently rab banerjee neuron mbl regulates plm biorxiv elegans mrnas cytoskeleton microtubule tubulin

Episode 021: Pharmacology 101: Part 2

The Fellow on Call

Play Episode Listen Later Jul 13, 2022

Picture this: it's day 1 of fellowship and your attending needs you to "get consent for treatment." Huh? How do you educate your patient? We share our tips! In this episode, we discuss important considerations, including “does my patient need a port?”, “what if drugs extravasate?”, “how do I keep side effects of drug classes straight?!” *The resources we share are our OWN opinions. Naming of resources are not endorsements. We are not sponsored by any of these entities. Pharmacology 101: * Irritant vs. Vesicant:** Each drug is deemed one of these based on the degree of tissue damage that can result if drug extravasates under skin.  ** Vesicant: needs central access ** Irritant: can be given peripherally  * Does my patient need a port/picc?** If vesicant; for continuous infusions over several days (e.g. 5-FU); some patients with difficult access may request.  *Advantages of ports: ** Easy access for labs ** Easy access for chemotherapy/fluids * Disadvantages: ** Risk of infection ** Risk of thrombosis  * General overview of chemotherapy side effects: ** Going to target the fastest growing cells in the body, which includes cells that line the GI tract, skin, hair/nails, and blood cells ** Therefore side effects are related: *** GI: nausea/vomiting, diarrhea (sometimes constipation), decreased appetite, taste changes *** Low blood counts **** WBC nadir ~10-14 days (generally), and recover 21-28 days after chemo * What about unique side effects of chemotherapy classes? How do we keep them straight?** We love keeping “Chemoman” from the USMLE study days in mind! * Anthracycline*** MOA: Topoisomerase inhibitors *** Ends in “rubicin” *** You might hear people call doxorubicin the “red devil” *** Used in lots of cancers *** Hair loss occurs with this one *** Known to cause cytopenias and associated with higher nausea potential  *** Unique side effects: **** Heart failure (always get baseline echo!) **** Development of MDS and leukemia  * Alkylating agents** MOA: Drugs add alkyl group to the guanine base of the DNA molecule, preventing linking of strands ** End in “fosfamide” ** fosfamide or cyclophosphamide (AKA cytoxan) ** Used in lots of cancers ** Known to cause cytopenias and hair loss ** Unique side effects:*** Secondary MDS or leukemia possible  *** Ifosfamide = neurotoxicity = methylene blue antidote *** Cyclophosphamide = hemorrhagic cystitis due to acrolein byproduct accumulation = prevent by giving mesna to protect bladder * Antimetabolites** MOA: Purine analog, pyrimidine analog, folate antagonists; therefore prevent production of base pairs or binds instead of normal base pairs ** End in “abine” - capecitabine, cytarabine, gemcitabine, cladribine, fludarabine ** Also 5-FU and 6-MP in this category so “number followed by dash”  ** Unique side effects:*** Think bone marrow suppression in this category  * Platinum agents** MOA: Believed to cause cross-linking of DNA ** End in “platin” ** Associated with high risk of neuropathy  ** Unique side effects: *** Cisplatin: **** Nephrotoxicity  **** Ototoxicity  **** High risk of nausea; need special prophylaxis  *** Carboplatin: cytopenias *** Oxaliplatin: higher rates GI side effects  * Microtubule agents** MOA: Impair microtubule function, therefore impacting cell division ** End in “taxel” or vincristine/vinblastine (“V-stine”) ** Unique side effects: Neuropathy Please visit our website (TheFellowOnCall.com) for more information Twitter: @TheFellowOnCallInstagram: @TheFellowOnCallListen in on: Apple Podcast, Spotify, and Google Podcast

spotify heart development dna risk unique hair picture ends apple podcast google podcasts aka gi advantages naming mp platinum wbc pharmacology mds usmle irritant cyclophosphamide carboplatin microtubule oxaliplatin

Oncology | Microtubule Inhibitors

Play Episode Listen Later Jun 29, 2022 12:39

In this episode, we review the high-yield topic of Microtubule Inhibitors from the Oncology section. Follow Medbullets on social media: Facebook: www.facebook.com/medbullets Instagram: www.instagram.com/medbulletsofficial Twitter: www.twitter.com/medbulletsIn this episode --- Send in a voice message: https://anchor.fm/medbulletsstep1/message

oncology inhibitors microtubule

MAG 198 - Precipice

The Magnus Archives

Play Episode Listen Later Mar 11, 2021 21:59

Case ########-38Navigating the descent, recorded in Situ.Content warnings:Heights / Vertigo (inc SFX)FallingPanic (inc breathing SFX)Injury / Pain (inc SFX)Explicit languageDiscussions of: emotional manipulationMentions of: arguments, death, self-hatred, lack of self-preservation, paranoia, pleading, kidnapping, alcoholSFX: wind, creaking metal, screaming & sufferingTranscripts:PDF - https://cutt.ly/9zEWNPkDOC - https://cutt.ly/mzEEqgIThanks to this week's Patrons: V Guest, Fiona Porter, Archimedes 871, Annabelle M, CJ, Cowboyhell, Timothy LaGrone, Jen Amico, Sean Hurley, monstrous venus, Madeleine Wenc, Hyst, Plim Flatterband, Daniel Prehm, Charlotte Farquhar, Catherine Cerny, emrys lee, iriki, Miles Frankel, deirdre, Lea F., Kat Lancaster, Eric Silva, Rebekah Paerels, Julian Sanchez, Leah Hunter, Kiri Baildon-Smith, Bonnie-Jo MacLeod, Noa Jamie Remus, Emilie Clifford, Ruby Mitchell, Carol McPherson, Jules Schaefer, Bradlee Allen, Azra, Jasper Vega, Audrey Salo, Nora, Sara Clark, Georgia Wilson, Clowder of One, Abby G, Elliot G Grace, ZeekiZeii, Harley Powell, Alandrea, Rowan Krieghbaum, ty, Colleen Moore.If you'd like to join them, visit www.patreon.com/rustyquill.Edited this week by Annie Fitch, Elizabeth Moffatt, Brock Winstead, Jeffrey Nils Gardner & Alexander J NewallWritten by Jonathan Sims and directed by Alexander J NewallSensitivity consultation by Alexander Linde NielsenProduced by Lowri Ann DaviesPerformances:- "The Archivist" - Jonathan Sims- "Martin Blackwood" - Alexander J Newall- "Basira Hussain" - Frank Voss- "Melanie King" - Lydia Nicholas- "Georgie Barker" - Sasha SiennaSound effects this week by ABouch, AderuMoro, aglinder, AlanCat, alec_mackay, annstory4520, bbrocer, bulbastre, Cell31_Sound_Productions, conleec, corpocracy, CUeckermann, DANMITCH3LL, Darth_Biomech, dersuperanton, dheming, dilsun, Eelke, eitabyte, felix.blume, FocusBay, gfrog, Huggy13ear, IESP, InspectorJ, j1987, jorickhoofd, JustinBW, kyles, laurenmartin236, Microtubule, MTJohnson, PeteIsCool, rkeato, Sauron974, sforsman, SocializedArtist45, speedygonzo, SpliceSound, sturmankin, SunnySideSound, ThunderQuads, tosha73, Volonda, Drkvixn91, nicklas3799, bevangoldswain, MadamVicious, yeopot & previously credited artists via freesound.org.Additional sound effects from https://www.zapsplat.com.Check out our merchandise available at https://www.redbubble.com/people/RustyQuill/shop & https://www.teepublic.com/stores/rusty-quill.You can subscribe to this podcast using your podcast software of choice, or by visiting www.rustyquill.com/subscribePlease rate and review on your software of choice, it really helps us to spread the podcast to new listeners, so share the fear.Join our community:WEBSITE:

edited cj situ precipice inspectorj archimedes azra iesp hyst eelke rusty quill splicesound julian sanchez jonathan sims microtubule colleen moore clowder sean hurley cell31 sound productions justinbw huggy13ear sunnysidesound brock winstead

MAG 197 - Connected

The Magnus Archives

Play Episode Listen Later Mar 4, 2021 25:33

Case ########-37A discussion on the edge of reality, recorded in situContent warnings:Heights & vertigo (inc. SFX)Spiders (inc. SFX)ManipulationBody horror (inc. SFX)ThreatsExplicit languageDiscussions of: altered reality, mass suffering, arsonMentions: mental disorientation, kidnapping, death & murder, apocalypse, paranoiaSFX: Insects, high-pitched sounds, overlapping voicesTranscripts:PDF - https://cutt.ly/Cl78av1DOC - https://cutt.ly/3l78vYaThanks to this week's Patrons: Laurel Buchanan, Maria Maksimova, Nikki, Seren Mist, Vince Nguyen, Asha Perry, DamienandFishGreco, Haberdasher, Jay Palmer, John Anglo, Jose Manuel Santiago Yepes, Katherine Bullen, Kyden Lundquist, Leah Higginbotham, lmx_v3point3, Melody Landrum, Mia, Moira Haney, Paravellex, Ray McKenzie, Rebecca Frederick, Rebekka B., Robin Dauster, Rowan Lorne, snowpossum, wrongsocks, Yo Mama', Zoke Miyama, Al LaBarrie, Ares Crowley, Calamari Matahari, E Kennedy, Kayla, Keelee, Lauga, Lena Klambauer, Lucia Kelly, QuizzicalQuibbler, sydney, Isabel Velasco, Vague Coffeecup, Kaela Woolsey, Morgan Short, Ahgbri Kanatist, WinglessWolf, Cece Henry, Lottie Rose, Charlie, Sonny AcostaIf you'd like to join them, visit www.patreon.com/rustyquill.Edited this week by Nico Vettese, Elizabeth Moffatt, Brock Winstead, Jeffrey Nils Gardner & Alexander J NewallWritten by Jonathan Sims and directed by Alexander J NewallProduced by Lowri Ann DaviesPerformances:- "The Archivist" - Jonathan Sims- "Martin Blackwood" - Alexander J Newall- "Annabelle Cane" - Chioma Nwalioba- "Basira Hussain" - Frank VossSound effects this week by 13F_Panska_Koprivikova_Klara, alienistcog, andersmmg, Andy_Gardner, APallot, Audionautics, aunrea, BarkersPinhead, baryy, BlueDelta, bone666138, BranRainey, cdrk, CGEffex, ChrisReierson, colorsCrimsonTears, CosmicEmbers, crashoverride61088, Darsycho, f-r-a-g-i-l-e, Fission9, FlatHill, freakinbehemoth, giddster, HerbertBoland, Humansounds55, ianoboe, InspectorJ, Jedimichael, juskiddink, JustinBW, Kinoton, kyles, lolamadeus, lzmraul, Microtubule, Native_Cell, Ornitorrinco, PeteBarry, qubodup, Reitanna, RICHERlandTV, rsellick, SamuelGremaud, soundscalpel.com, speedygonzo, straget, SunnySideSound, tcowboy, tim.kahn, tmkappelt, vckhaze, Veridiansunrise, vibe_crc, wilhelmsqueek, xtrgamr, zmobie & previously credited artists via freesound.org.Additional sound effects from Zapsplat.com and from Little Robot Sound Factory via Zapsplat.Check out our merchandise available at https://www.redbubble.com/people/RustyQuill/shop & https://www.teepublic.com/stores/rusty-quill.You can subscribe to this podcast using your podcast software of choice, or by visiting www.rustyquill.com/subscribePlease rate and review on your software of choice, it really helps us to... See acast.com/privacy for privacy and opt-out information.

connected edited heights inspectorj zapsplat yo mama cgeffex rusty quill herbertboland ornitorrinco kinoton haberdasher jonathan sims richerlandtv reitanna microtubule nico vettese justinbw sunnysidesound rebekka b brock winstead

Robbing the Cranium with Rob Chavez

CM1-driven assembly and activation of Yeast γ-Tubulin Small Complex underlies microtubule nucleation

PaperPlayer biorxiv biochemistry

Play Episode Listen Later Nov 22, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.11.21.392803v1?rss=1 Authors: Brilot, A. F., Lyon, A., Zelter, A., Viswanath, S., Maxwell, A., MacCoss, M. J., Muller, E. G., Sali, A., Davis, T. N., Agard, D. A. Abstract: Microtubule (MT) nucleation is regulated by the {gamma}-tubulin ring complex ({gamma}TuRC), conserved from yeast to humans. In Saccharomyces cerevisiae, {gamma}TuRC is composed of seven identical {gamma}-tubulin small complex ({gamma}TuSC) sub-assemblies which associate helically to template microtubule growth. {gamma}TuRC assembly provides a key point of regulation for the MT cytoskeleton. Here we combine cross-linking mass spectrometry (XL-MS), X-ray crystallography and cryo-EM structures of monomeric and dimeric {gamma}TuSC and open and closed helical {gamma}TuRC assemblies in complex with Spc110p to elucidate the mechanisms of {gamma}TuRC assembly. {gamma}TuRC assembly is substantially aided by the evolutionarily conserved CM1 motif in Spc110p spanning a pair of adjacent {gamma}TuSCs. By providing the highest resolution and most complete views of any {gamma}TuSC assembly, our structures allow phosphorylation sites to be mapped, suggesting their role in regulating spindle pole body attachment and ring assembly. We further identify a structurally analogous CM1 binding site in the human {gamma}TuRC structure at the interface between GCP2 and GCP6, which allows for the interpretation of significant structural changes arising from CM1 helix binding to metazoan {gamma}TuRC. Copy rights belong to original authors. Visit the link for more info

mt driven complex copy lyon assembly activation muller yeast sali turc agard cm1 biorxiv viswanath tusc nucleation microtubule tubulin

Schizophrenia and autism-associated mutations and disrupted m6A signal by YTHDF1 cause defects in microtubule function and neurodevelopment

Play Episode Listen Later Nov 14, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.11.14.382556v1?rss=1 Authors: Roy, R., Li, X., Hou, S., Fujiwara, Y., Sukegawa, M., Hong, W.-T., Oomoto, I., Ito, H., Joshi, K., Fan, R., Nagata, K.-i., Lai, K.-o., Wang, D. O. Abstract: Building and maintaining neuronal networks and cognitive functions require mRNA localization and regulated protein synthesis in neurons. RNA modification N6-methyl-adenosine (m6A) has recently been shown in axonal and synaptically localized mRNAs whose local activity is required for axon growth, synaptogenesis, and neuronal plasticity. However, no cellular pathways engaging local epitranscriptomic modulation are known to underlie these post-mitotic neuronal functions. Now we report that cytoplasmic m6A reader YTHDF1 is enriched in neurons and required for axonal, dendritic, and spine development. We show that m6A and YTHDF1 are part of a microtubule plus-end associated RNA granule that contains extensive networks of mRNAs organized by autism risk gene adenomatous polyposis coli (APC). Disrupting m6A signals by knocking down methyltransferase METTL14 or YTHDF1, or overexpressing autism or schizophrenia-associated missense mutations I311V or S399L in human METTL14, reduce expression of APC granule and tubulin, disrupt microtubule assembly and function. These results reveal a novel neuronal subcellular locus for epitranscriptomic regulation to promote post-mitotic neurodevelopment. Copy rights belong to original authors. Visit the link for more info

autism signal copy li function wang mrna mutation schizophrenia hong rna disrupted joshi hou defects lai ito apc neurodevelopment fujiwara nagata biorxiv mrnas n6 microtubule

A Structural Ensemble of a Tau-Microtubule Complex Reveals Regulatory Tau Phosphorylation and Acetylation Mechanisms

alzheimer's disease complex copy ensemble regulatory structural mechanisms bernardes biorxiv phosphorylation microtubule

Play Episode Listen Later Nov 10, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.11.10.376285v1?rss=1 Authors: Brotzakis, Z. F., Lindstedt, P., Taylor, R., Bernardes, G., Vendruscolo, M. Abstract: Tau is a microtubule-associated protein that regulates the stability of microtubules. The affinity of tau for microtubules is modulated by post-translational modifications, and the dysregulation of these events has been associated with the aberrant aggregation of tau in Alzheimer's disease and related tauopathies. Here, we use the metainference cryo- electron microscopy approach to determine an ensemble of structures representing the structure and dynamics of a tau-microtubule complex comprising an extended microtubule-binding region of tau (residues 202-395). We thus identify the ground state of the complex and a series of excited states of lower populations. An analysis of the interactions in these states of structures reveals positions in the tau sequence that are important to determine the overall stability of the tau-microtubule complex. This analysis leads to the identification of positions where phosphorylation and acetylation events have destabilising effects, which we validate by using site-specific post-translationally modified tau variants obtained by chemical mutagenesis. Taken together, these results illustrate how the simultaneous determination of ground and excited states of macromolecular complexes reveals functional and regulatory mechanisms. Copy rights belong to original authors. Visit the link for more info

HI:W HALLOWEEN 2020

Hobbies Include: Writing

Play Episode Listen Later Oct 28, 2020 26:19

Enjoy a fully produced short horror story by host, writer and creator Mariah PowellPatreon: https://www.patreon.com/hobbiesinclude_writing?fan_landing=true Website: hobbiesinclude-writing.weebly.com Facebook.com/hobbiesincludewriting Twitter: @HIWPodcast Black Ice Comics: https://www.blackicecomics.com/ Music edited from: Chill Wave by Kevin MacLeod Link: https://incompetech.filmmusic.io/song/3498-chill-wave License: http://creativecommons.org/licenses/by/4.0/ and S: Melon beating.wav by Microtubule -- https://freesound.org/s/535364/ -- License: Attribution Project Entertainment Network: https://projectentertainmentnetwork.com/ Alien Beer Podcast: https://alienbeer.podbean.com/ Silly Hat Books: https://sillyhatbooks.com/ Fredericksburg Literary and Art Review: https://fredericksburg-literary-and-art-review.square.site/

music halloween fall writing transformation horror witches poetry fiction halloween special kevin macleod poem short fiction horror fiction chillwave art review microtubule

The mechanism of motor inhibition by microtubule-associated proteins

Play Episode Listen Later Oct 23, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.22.351346v1?rss=1 Authors: Ferro, L. S., Eshun-Wilson, L., Golcuk, M., Fernandes, J., Huijben, T., Gerber, E., Jack, A., Costa, K., Gur, M., Feng, Q., Nogales, E., Yildiz, A. Abstract: Microtubule (MT)-associated proteins (MAPs) regulate intracellular transport by selectively recruiting or excluding kinesin and dynein motors from MTs. We used single-molecule and cryo-electron imaging to determine the mechanism of MAP-motor interactions in vitro. Unexpectedly, we found that the regulatory role of a MAP cannot be predicted based on whether it overlaps with the motor binding site or forms liquid condensates on the MT. Although the MT binding domain (MTBD) of MAP7 overlaps with the kinesin-1 binding site, tethering of kinesin-1 by the MAP7 projection domain supersedes this inhibition and results in biphasic regulation of kinesin-1 motility. Conversely, the MTBD of tau inhibits dynein motility without overlapping with the dynein binding site or by forming tau islands on the MT. Our results indicate that MAPs sort intracellular cargos moving in both directions, as neither dynein nor kinesin can walk on a MAP-coated MT without favorably interacting with that MAP. Copy rights belong to original authors. Visit the link for more info

mt costa copy maps motor map conversely fernandes gerber mechanism proteins unexpectedly feng mts inhibition nogales gur yildiz biorxiv microtubule

Single depolymerizing and transport kinesins stabilize microtubule ends

single ends copy transport schaeffer stabilize biorxiv sudhakar microtubule

Play Episode Listen Later Oct 5, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.05.326330v1?rss=1 Authors: Ciorita, A., Bugiel, M., Sudhakar, S., Schaeffer, E., Jannasch, A. Abstract: Microtubules are highly dynamic cellular filaments and many intracellular processes like cell division depend on an accurate control of their length. Among other factors, microtubule length is actively modulated by motors from the kinesin superfamily. For example, yeast kinesin-8, Kip3, depolymerizes microtubules in a collective manner by a force and length-dependent mechanism. However, whether single motors depolymerize or stabilize microtubule ends is unclear. Here, using interference reflection microscopy, we measured the influence of single kinesin motors on the stability of microtubules in an in vitro assay. Surprisingly, using unlabeled, stabilized microtubules, we found that both single kinesin-8 and non-depolymerizing kinesin-1 transport motors stabilized microtubule ends further by reducing the spontaneous microtubule depolymerization rate. Since we observed this effect for two very different kinesins, it implies a more general stabilization mechanism. For Kip3, this behavior is contrary to the collective force-dependent depolymerization activity of multiple motors. The complex, concentration-dependent interaction with microtubule ends provides new insights into the molecular mechanism of kinesin-8 and its regulatory function of microtubule length. Copy rights belong to original authors. Visit the link for more info

Proximity-dependent proteomics reveals extensive interactions of Protocadherin-19 with regulators of Rho GTPases and the microtubule cytoskeleton

Play Episode Listen Later Sep 11, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.11.293589v1?rss=1 Authors: Emond, M. R., Biswas, S., Morrow, M. L., Jontes, J. Abstract: Protocadherin-19 belongs to the cadherin family of cell surface receptors and has been shown to play essential roles in the development of the vertebrate nervous system. Mutations in human Protocadherin-19 (PCDH19) lead to PCDH19 Female-limited epilepsy (PCDH19 FLE) in humans, characterized by the early onset of epileptic seizures in children and a range of cognitive and behavioral problems in adults. Despite being considered the second most prevalent gene in epilepsy, very little is known about the intercellular pathways in which it participates. In order to characterize the protein complexes within which Pcdh19 functions, we generated Pcdh19-BioID fusion proteins and utilized proximity-dependent biotinylation to identify neighboring proteins. Proteomic identification and analysis revealed that the Pcdh19 interactome is enriched in proteins that regulate Rho family GTPases, microtubule binding proteins and proteins that regulate cell divisions. We cloned the centrosomal protein Nedd1 and the RacGEF Dock7 and verified their interactions with Pcdh19 in vitro. Our findings provide the first comprehensive insights into the interactome of Pcdh19, and provide a platform for future investigations into the cellular and molecular biology of this protein critical to the proper development of the nervous system. Copy rights belong to original authors. Visit the link for more info

copy interactions regulators dependent mutation proximity extensive morrow rho biswas proteomics biorxiv proteomic cytoskeleton microtubule gtpases jontes

Confinement size determines the architecture of Ran-induced microtubule networks

PaperPlayer biorxiv biochemistry

Play Episode Listen Later Sep 1, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.01.277186v1?rss=1 Authors: Gai, Y., Cook, B., Satru, S., Stone, H. A., Petry, S. Abstract: The organization of microtubules (MTs) is critical for cells during interphase and mitosis. During mitotic spindle assembly, MTs are made and organized around chromosomes in a process regulated by RanGTP. The role of RanGTP has been explored in Xenopus egg extracts, which are not limited by a cell membrane. Here, we investigated whether cell-sized confinements affect the assembly of RanGTP-induced MT networks in Xenopus egg extracts. We used microfluidics to encapsulate extracts within monodisperse extract-in-oil droplets. Importantly, we find that the architecture of Ran-induced MT networks depends on the droplet diameter and the Ran concentration, and differs from structures formed in bulk extracts. Our results highlight that both MT nucleation and physical confinement play critical roles in determining the spatial organization of the MT cytoskeleton. Copy rights belong to original authors. Visit the link for more info

stone mt cook architecture copy networks confinement determines induced ran petry mts biorxiv xenopus microtubule

Branching microtubule nucleation is controlled by importin-mediated inhibition of TPX2 phase separation

Play Episode Listen Later Sep 1, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.01.276469v1?rss=1 Authors: Safari, M. S., King, M. R., Brangwynne, C. P., Petry, S. Abstract: The microtubule-based mitotic spindle is responsible for equally partitioning the genome during each cell division, and its assembly is executed by several microtubule nucleation pathways. In the spindle center, Targeting Protein for XKlp2 (TPX2) promotes branching microtubule nucleation, where new microtubules are nucleated from pre-existing ones. Until the onset of spindle assembly, TPX2 is sequestered by importins-/{beta}, yet the molecular nature of this regulation remains unclear, particularly since TPX2 was recently found to undergo a liquid-liquid phase separation to execute its function. Here we demonstrate that TPX2 interacts with importins-/{beta} with nanomolar affinity as a 1:1:1 mono-dispersed trimer. We identify a new nuclear localization sequence (NLS) on TPX2, which contributes to its high-affinity interaction with importin-. Interestingly, importin-{beta} alone can also associate with TPX2, and does so via dispersed, weak interactions. Interactions of both importin- and importin-{beta} with TPX2 each inhibit its propensity for phase separation, and consequently its ability to orchestrate branching microtubule nucleation. In sum, our study explains how TPX2 is regulated in order to facilitate spindle assembly, and provides novel insight into how a protein phase separation can be inhibited via weak biomolecular interactions. Copy rights belong to original authors. Visit the link for more info

phase separation copy controlled interactions branching petry inhibition mediated nls biorxiv nucleation microtubule

Swirling Instability of the Microtubule Cytoskeleton

studies copy goldstein instability swirling biorxiv cytoskeleton microtubule

Play Episode Listen Later Aug 27, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.27.268318v1?rss=1 Authors: Stein, D. B., De Canio, G., Lauga, E., Shelley, M. J., Goldstein, R. E. Abstract: In the cellular phenomena of cytoplasmic streaming, molecular motors carrying cargo along a network of microtubules entrain the surrounding fluid. The piconewton forces produced by individual motors are sufficient to deform long microtubules, as are the collective fluid flows generated by many moving motors. Studies of streaming during oocyte development in the fruit fly D. melanogaster have shown a transition from a spatially-disordered cytoskeleton, supporting flows with only short-ranged correlations, to an ordered state with a cell-spanning vortical flow. To test the hypothesis that this transition is driven by fluid-structure interactions we study a discrete-filament model and a coarse-grained continuum theory for motors moving on a deformable cytoskeleton, both of which are shown to exhibit a swirling instability to spontaneous large-scale rotational motion, as observed. Copy rights belong to original authors. Visit the link for more info

Two modes of PRC1-mediated mechanical resistance to kinesin-driven microtubule network disruption

Play Episode Listen Later Aug 10, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.10.244491v1?rss=1 Authors: Alfieri, A., Gaska, I., Forth, S. Abstract: The proper structural organization of the microtubule-based spindle during cell division requires the collective activity of many different types of proteins. These include non-motor microtubule-associated proteins (MAPs) whose functions include crosslinking microtubules to regulate filament sliding rates and assembling microtubule arrays. One such protein is PRC1, an essential MAP that has been shown to preferentially crosslink overlapping antiparallel microtubules at the spindle midzone. PRC1 has been proposed to act as a molecular brake, but insight into the mechanism of how PRC1 molecules function cooperatively to resist motor-driven microtubule sliding and to allow for the formation of stable midzone overlaps has been lacking. Here we employ a modified microtubule gliding assay to rupture PRC1-mediated microtubule pairs using surface-bound kinesins. We discovered that PRC1 crosslinks always reduce bundled filament sliding velocities relative to single microtubule gliding rates, and do so via two distinct emergent modes of mechanical resistance to motor-driven sliding. We term these behaviors braking and coasting, where braking events exhibit substantially slowed microtubule sliding compared to coasting events. Strikingly, braking behavior requires the formation of two distinct high-density clusters of PRC1 molecules near microtubule tips. Our results suggest a cooperative mechanism for PRC1 accumulation when under mechanical load that leads to a unique state of enhanced resistance to filament sliding and provides insight into collective protein ensemble behavior in regulating the mechanics of spindle assembly. Copy rights belong to original authors. Visit the link for more info

network resistance driven disruption copy maps map mechanical modes mediated strikingly biorxiv gaska microtubule kinesin

Age and dose-dependent effects of alpha-lipoic acid on human microtubule-associated protein tau-induced endoplasmic reticulum unfolded protein response: implications for Alzheimers disease

PaperPlayer biorxiv biochemistry

Play Episode Listen Later Aug 3, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.31.230847v1?rss=1 Authors: Zarini-Gakiye, E., Sanadgol, N., Parivar, K., Vaezi, G. Abstract: Background: In human tauopathies, pathological aggregation of misfolded/unfolded proteins particularly microtubule-associated protein tau (MAPT, tau) is considered to be essential mechanisms that trigger the induction of endoplasmic reticulum (ER) stress. Here we assessed the molecular effects of natural antioxidant alpha-lipoic acid (ALA) in human tauR406W (htau)-induced ER unfolded protein response (ERUPR) in the young and older flies. Methods: In order to reduce htau neurotoxicity during brain development, we used a transgenic model of tauopathy where the maximum toxicity was observed in adult flies. Then, the effects of ALA (0.001, 0.005, and 0.025% w/w of diet) in htau-induced ERUPR in the ages 20 and 30 days were evaluated. Results: Data from expression (mRNA and protein) patterns of htau, analysis of eyes external morphology as well as larvae olfactory memory were confirmed our tauopathy model. Moreover, expression of ERUPR-related proteins involving activating transcription factor 6 (ATF6), inositol regulating enzyme 1 (IRE1), and protein kinase RNA-like ER kinase (PERK) were upregulated and locomotor function decreased in both ages of the model flies. Remarkably, the lower dose of ALA modified ERUPR and supported the reduction of behavioral deficits in youngest adults through enhancement of GRP87/Bip, reduction of ATF6, downregulation of PERK-ATF4 pathway, and activation of the IRE1-XBP1 pathway. On the other hand, only a higher dose of ALA was able to affect the ERUPR via moderation of PERK-ATF4 signaling in the oldest adults. As ALA exerts their higher protective effects on the locomotor function of younger adults when htauR406W expressed in all neurons (htau-elav) and mushroom body neurons (htau-ok), we proposed that ALA has age-dependent effects in this model. Conclusion: Taken together, based on our results we conclude that aging potentially influences the ALA effective dose and mechanism of action on tau-induced ERUPR. Further molecular studies will warrant possible therapeutic applications of ALA in age-related tauopathies. Copy rights belong to original authors. Visit the link for more info

er effects alzheimer's disease implications copy dose mrna dependent rna induced ala perk biorxiv alpha lipoic acid microtubule endoplasmic reticulum unfolded protein response

Competitive Microtubule Binding of PEX14 Coordinates Peroxisomal Protein Import and Motility

Play Episode Listen Later Jul 23, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.23.218024v1?rss=1 Authors: Erdmann, R., Neuhaus, A., Bruehl, L., Bharti, P., Schliebs, W., Sattler, M., Kooshapur, H., Suda, J., Jung, M. Abstract: PEX14 functions as peroxisomal docking protein for the import receptor PEX5. For docking, the conserved N-terminal domain of PEX14 (PEX14-NTD) binds amphipathic alpha-helical ligands, typically comprising one or two aromatic residues, of which human PEX5 possesses eight. Here, we show that the PEX14-NTD also binds to microtubular filaments in vitro with a dissociation constant in nanomolar range. PEX14 interacts with two motifs in the C-terminal region of human {beta}-tubulin. At least one of the binding motifs is in spatial proximity to the binding site of microtubules (MT) for kinesin. Both PEX14 and kinesin can bind to MT simultaneously. Notably, binding of PEX14 to tubulin can be prevented by its association with PEX5. The data suggest that PEX5 competes peroxisome anchoring to MT by occupying the {beta}-tubulin-binding site of PEX14. The competitive correlation of matrix protein import and motility may facilitate the homogeneous dispersion of peroxisomes in mammalian cells. Copy rights belong to original authors. Visit the link for more info

mt competitive copy protein jung import notably binding sattler neuhaus suda coordinates motility bharti biorxiv microtubule

Vesicle Navigation of Microtubule Ends Distinguished by A Single Rate-Constant Model

Play Episode Listen Later Jul 21, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.21.214023v1?rss=1 Authors: Gramlich, M. W., Balseiro Gomez, S., Tabei, S. M. A., Parkes, M., Yogev, S. Abstract: Axonal motor driven cargo utilizes the microtubule cytoskeleton in order to direct cargo, such as presynaptic vesicle precursors, to where they are needed. This transport requires vesicles to travel up to microns in distance. It has recently been observed that finite microtubule lengths can act as roadblocks inhibiting vesicles and increasing the time required for transport. Vesicles reach the end of a microtubule and pause until they can navigate to a neighboring microtubule in order to continue transport. The mechanism by which axonal vesicles navigate the end of a microtubule in order to continue mobility is unknown. In this manuscript we model experimentally observed vesicle pausing at microtubule ends in C. elegans. We show that a single rate-constant model reproduces the time vesicles pause at MT-ends. This model is based on the time a vesicle must detach from its current microtubule and re-attach to a neighboring microtubule. We show that vesicle pause times are different for anterograde and retrograde motion, suggesting that vesicles utilize different proteins at plus and minus end sites. Last, we show that vesicles do not likely utilize a tug-of-war like mechanism and reverse direction in order to navigate microtubule ends. Copy rights belong to original authors. Visit the link for more info

single model mt ends constant copy navigation distinguished parkes biorxiv vesicles yogev microtubule vesicle

Subcellular localization of TAU isoforms and their influence on microtubule dynamics

Play Episode Listen Later Jun 17, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.06.16.154757v1?rss=1 Authors: Bachmann, S., Bell, M., Klimek, J., Zempel, H. Abstract: In the adult human brain, six isoforms of the microtubule-associated protein TAU are expressed, which result from alternative splicing of exons 2, 3 and 10 of the MAPT gene. These isoforms differ in the number of N-terminal inserts (0N, 1N, 2N) and C-terminal repeat domains (3R or 4R) and are differentially expressed depending on the brain region and developmental stage. Although all TAU isoforms can aggregate and form neurofibrillary tangles, some tauopathies, such as Pick's Disease and Progressive Supranuclear Palsy, are characterized by the accumulation of specific TAU isoforms. Many studies focused on the role of TAU in these diseases, however only few addressed isoform-specific functions of TAU in healthy and under pathological conditions. In this report, we investigated the subcellular localization of the human-specific TAU isoforms in primary mouse neurons. Our results show that 2N-TAU isoforms are particularly retained from axonal sorting and that axonal enrichment is independent from the number of repeat domains. Furthermore, we analyzed TAU isoform-specific effects on cell area and microtubule dynamics in SH-SY5Y neuroblastoma cells and observed a general reduction of cell size and an increase of microtubule counts in cells expressing 4R-TAU isoforms. Our study points out TAU isoform-specific effects that will be addressed in follow-up studies to unravel if and how TAU isoforms contribute to cellular functions in health and disease. Copy rights belong to original authors. Visit the link for more info

influence disease copy dynamics tau localization 3r klimek 4r biorxiv 1n progressive supranuclear palsy microtubule sh sy5y

MARK4 with an Alzheimer's disease-related mutation promotes tau hyperphosphorylation directly and indirectly and exacerbates neurodegeneration

alzheimer's disease copy blocking mark 4 ando mutation promotes saito asada neurodegeneration drosophila indirectly shimizu biorxiv in ad microtubule

Play Episode Listen Later May 23, 2020

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.20.107284v1?rss=1 Authors: Oba, T., Saito, T., Asada, A., Shimizu, S., Iijima, K. M., Ando, K. Abstract: Accumulation of the microtubule-associated protein tau is associated with Alzheimers disease (AD). In AD brain, tau is abnormally phosphorylated at many sites, and phosphorylation at Ser262 and Ser356 play critical roles in tau accumulation and toxicity. Microtubule-affinity regulating kinase 4 (MARK4) phosphorylates tau at those sites, and a double de novo mutation in the linker region of MARK4, G316E317InsD, is associated with an elevated risk of AD. However, it remains unclear how this mutation affects phosphorylation, aggregation, and accumulation of tau and tau-induced neurodegeneration. Here, we report that MARK4G316E317D increases the abundance of highly phosphorylated, insoluble tau species and exacerbates neurodegeneration via Ser262/356-dependent and -independent mechanisms. Using transgenic Drosophila expressing human MARK4 (MARK4wt) or a mutant version of MARK4 (MARK4G316E317D), we found that co-expression of MARK4wt and MARK4G316E317D increased total tau levels and enhanced tau-induced neurodegeneration, and that MARK4G316E317D had more potent effects than MARK4wt. Interestingly, the in vitro kinase activities of MARK4wt and MARK4G316E317D were similar. Blocking tau phosphorylation at Ser262 and Ser356 by alanine substitutions protected tau from the effects of MARK4wt, but not from MARK4G316E317D. While both MARK4wt and MARK4G316E317D increased the levels of oligomeric forms of tau, MARK4G316E317D further boosted the levels of tau phosphorylated at several sites other than Ser262/356 and increased the detergent insolubility of tau in vivo. Together, these findings suggest that MARK4G316E317D increases tau levels and exacerbates tau toxicity via an additional gain-of-function mechanism, and that modification in this region of MARK4 may impact disease pathogenesis. Copy rights belong to original authors. Visit the link for more info

The Jewel Network

The JEWEL Network

Play Episode Listen Later Nov 16, 2017 80:00

The Jewel Network melanin the brain and the microtubule part 1 oct 13 2010

network melanin microtubule

biosights: December 21, 2015

biosights

Play Episode Listen Later Dec 21, 2015 7:12

How catastrophes help oocytes avoid disaster During meiosis, oocytes must attach homologous chromosomes to opposite spindle poles, but the cells take several hours to assemble a bipolar spindle. Gluszek et al. reveal that, in Drosophila oocytes, the microtubule catastrophe–promoting protein Sentin delays the formation of stable kinetochore–microtubule attachments until spindle assembly is complete, thereby preventing homologous chromosomes from incorrectly attaching to the same spindle pole. This biosights episode presents the paper by Głuszek et al. from the December 21st, 2015, issue of The Journal of Cell Biology and includes an interview with the paper's senior author, Hiroyuki Ohkura (University of Edinburgh, Edinburgh, Scotland, UK). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research. Subscribe to biosights via iTunes or RSS View biosights archive The Rockefeller University Press biosights@rockefeller.edu

uk scotland journal edinburgh scotland cell biology jcb drosophila meiosis oocyte eb1 microtubule

Lecture 22 - Microtubule, kinesin & dynein

01:146:470:01 F13's official Podcast.

Play Episode Listen Later Nov 18, 2013

Mon, 18 Nov 2013 10:35:12 GMT https://sakai.rutgers.edu/access/content/group/c7b3269a-bc92-488e-b4b1-0e20648073af/Podcasts/Lect

lecture microtubule kinesin

Science Signaling Podcast, 7 August 2012

Science Signaling Podcast

Play Episode Listen Later Aug 6, 2012 15:51

Drugs that reduce microtubule density or prevent the production of reactive oxygen species in skeletal muscle might slow the progression of Duchenne muscular dystrophy.

science drugs repair regeneration calcium signaling duchenne duchenne muscular dystrophy reactive oxygen species cytoskeleton microtubule nox2 dystrophin

Microtubule Length Regulation by Molecular Motors

Physik - Open Access LMU - Teil 01/02

Play Episode Listen Later Jun 1, 2012

Length regulation of microtubules (MTs) is essential for many cellular processes. Molecular motors like kinesin-8, which move along MTs and also act as depolymerases, are known as key players in MT dynamics. However, the regulatory mechanisms of length control remain elusive. Here, we investigate a stochastic model accounting for the interplay between polymerization kinetics and motor-induced depolymerization. We determine the dependence of MT length and variance on rate constants and motor concentration. Moreover, our analyses reveal how collective phenomena lead to a well-defined MT length.

mt regulation molecular motors physik mts microtubule ddc:530

Studies on microtubule nucleation during axon growth

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 04/06

Play Episode Listen Later Dec 3, 2010

Neurons are the signaling cells of the nervous system. To propagate signals, neurons elongate several neurites, which differentiate into a single axon and several dendrites during development. Among the factors that contribute to this differentiation process, the cytoskeleton and in particular the microtubules play a key role. For instance, the growth of the axon and the dendrites depends on dynamic microtubules and requires the formation of new microtubules. The centrosome is regarded as the primary source of microtubules in axonal and dendritic growth and has been proposed to direct axon formation. However, while microtubule nucleation from centrosomes enables efficient spindle-pole organization and cytokinesis during cell division, it is difficult to reconcile the distinct microtubule array in branching axons, dendrites and spines with such focal microtubule assembly. Thus, the exact role of the centrosome and centrosomal microtubule nucleation in axon growth is still unclear. To address this question, my doctoral research focused on where microtubules are generated in developing neurons and what role centrosomal microtubule nucleation plays in axonal growth. Using rodent hippocampal neurons in culture as a model system, I found that the centrosome loses its function as a microtubule organizing center (MTOC) during neuronal development. The microtubule nucleating factor gamma-tubulin was depleted from the centrosome. Consequently, after depolymerization with nocodazole, microtubules did not regrow at the centrosome at later stages of development. Nevertheless, acentrosomal microtubule nucleation still occurred. Furthermore, axonal growth was unchanged after the centrosome has lost its activity. Moreover, when the axon was lesioned in mature neurons, a new axon grew out in the absence of centrosomal gamma-tubulin. As axons grow in mature neurons without a functional centrosome, I next asked the question of whether axon growth requires centrosomal microtubule nucleation in earlier stages of development, when the centrosome still functions as a MTOC. With the use of a two-photon laser ablation setup, the centrosome was removed in neurons that just started to form an axon. Intriguingly, the neurons retained the ability to grow an axon when the centrosome had been ablated by a laser. Thus, loss of centrosomal microtubule nucleation is not a limiting factor for axon growth and regeneration. My research implies that acentrosomal microtubule assembly is a key feature to establish the sophisticated cytoskeleton of neurons, which is the source for their complex morphology. While the centrosome is necessary for cell cycle progression and neurogenesis, neuronal differentiation requires sophisticated architectural changes that may be incompatible with a large microtubule network emanating from a focal point. Thus, acentrosomal microtubule nucleation may be a key feature during differentiation of neuronal, but also of non-neuronal cells. Dismantling the centrosome and decentralizing microtubule nucleation may be essential to enable axon branching, dendrite formation and spine generation.

growth studies dismantling neurons axon intriguingly nucleation ddc:500 microtubule ddc:570

Electronic Transport Properties of a Single Microtubule

Center for Consciousness Studies

Play Episode Listen Later Nov 9, 2010 54:49

single electronic transport properties microtubule

CLIPs regulate neuronal polarization through microtubule and growth cone dynamics

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 04/06

Play Episode Listen Later Jul 19, 2010

Mon, 19 Jul 2010 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/12663/ https://edoc.ub.uni-muenchen.de/12663/1/Neukirchen_Dorothee.pdf Neukirchen, Dorothee ddc:570, ddc:500, Fakultät fü

growth dynamics clips regulate cone polarization fakult neuronal ddc:500 microtubule ddc:570

biosights: May 17, 2010

biosights

Play Episode Listen Later May 17, 2010 5:48

Drosophila macrophages disperse themselves around the body during embryogenesis, ready to mount an immune response at the site of a wound. Stramer et al. image the cells in vivo, revealing that they form microtubule "arms" to point them in the right direction and push themselves away from their fellow leukocytes. This biosights episode presents the paper by Stramer et al. from the May 17th, 2010 issue of The Journal of Cell Biology, and includes an interview with lead author Brian Stramer. Produced by Caitlin Sedwick and Ben Short. Subscribe to biosights via iTunes or RSS View biosights archive The Rockefeller University Press biosights@rockefeller.edu

journal orbits cell biology drosophila clasp macrophages microtubule

Microtubule Motors and Axonal Transport: Function and Dysfunction in Neurodegenerative Disease

Videocast Podcasts

Play Episode Listen Later Mar 17, 2010 69:35

Enhanced Video PodcastAired date: 3/15/2010 12:00:00 PM Eastern Time

transport dysfunction motors neurodegenerative diseases microtubule

Microtubule Motors and Axonal Transport: Function and Dysfunction in Neurodegenerative Disease

Videocast Podcasts

Play Episode Listen Later Mar 17, 2010 69:35

Enhanced Audio PodcastAired date: 3/15/2010 12:00:00 PM Eastern Time

transport dysfunction motors neurodegenerative diseases microtubule

biosights: December 23, 2009

biosights

Play Episode Listen Later Dec 23, 2009 7:58

Mitotic spindle microtubules have long been thought to deliver a signal to the cell cortex that positions the cytokinetic cleavage furrow. A new study reveals that accurate cytokinesis still occurs in the absence of contact between microtubules and the plasma membrane, and suggests that multiple spatial cues combine to define the furrow's location. This biosights episode presents the paper by von Dassow et al. from the December 14th, 2009 issue of the Journal of Cell Biology, and includes interviews with authors George von Dassow and Bill Bement. Produced by Eun Choi and Ben Short. Subscribe to biosights via iTunes or RSS View biosights archive The Rockefeller University Press biosights@rockefeller.edu

journal aster cell biology microtubule mitotic

The role of microtubules in initial neuronal polarization

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 03/06

Play Episode Listen Later Jul 9, 2008

Neurons are highly polarized cells with two structurally and functionally distinct compartments, axons and dendrites. This dichotomy is the basis for unidirectional signal propagation, the quintessential function of neurons. During neuronal development, the formation of the axon is the initial step in breaking cellular symmetry and the establishment of neuronal polarity. Although a number of polarity regulators involved in this process have been identified, our understanding of the intracellular mechanisms underlying neuronal polarization still remains fragmentary. In my studies, I addressed the role of microtubule dynamics in initial neuronal polarization. To this end I aimed to investigate the following issues: 1) How do microtubule dynamics and stability change during initial neuronal development? 2) Do microtubules play an instructive role in axon formation? 3) What are possible regulators mediating changes in microtubule dynamics during axon formation? Using hippocampal neurons in culture as a model system for neuronal polarization I first addressed the dynamics of microtubules in early developmental stages of neurons. Assessing posttranslational modifications of tubulin which serve as markers of microtubule turnover I found that microtubule stability is increased in a single neurite already before axon formation and in the axon of morphologically polarized cells. This polarized distribution of microtubule stability was confirmed by testing the resistance of neuronal microtubules to pharmacologically induced depolymerization. The axon of polarized neurons and a single neurite in morphologically unpolarized cells showed increased microtubule stability. Thus, I established a correlation between the identity of a process and its microtubule stability. By manipulating specific regulators of neuronal polarity, SAD kinases and GSK-3beta, I analyzed a possible relation between a polarization of microtubule stability and neuronal polarity. I found that a loss of polarity correlated with a loss of polarized microtubule stability in neurons defective for SAD A and SAD B kinases. In marked contrast, the formation of multiple axons, induced by the inhibition of GSK-3beta, was associated with increased microtubule stability in these supernumerary axons. These results suggested that SAD kinases and GSK-3beta regulate neuronal polarization –at least in part– by modulating microtubule dynamics. To establish a possible causal relation between microtubule dynamics and axon formation I assessed the effects of specific pharmacological alterations of microtubule dynamics on neuronal polarization. I found that application of low doses of the microtubule destabilizing drug nocodazole selectively reduced the formation of future dendrites. Conversely, low doses of the microtubule stabilizing drug taxol led to the formation of multiple axons. I also studied microtubule dynamics in living neurons transfected with GFP-tagged EB3, a protein binding specifically to polymerizing microtubule plus ends. In line with my previous observations I found that microtubules are stabilized along the shaft of the growing axons while dynamic microtubules enrich at the tip of the growing process, suggesting that a well- balanced shift of microtubule dynamics towards more stable microtubules is necessary to induce axon formation. By uncaging a photoactivatable analog of taxol I induced a local stabilization of microtubules at the neurite tip of an unpolarized neuron which was sufficient to favor the site of axon formation. This indicates that a transient stabilization of microtubules is sufficient to trigger axon formation. In summary, my data allow the following conclusions: 1) Microtubule stability correlates with the identity of a neuronal process. 2) Microtubule stabilization causes axon formation. 3) Microtubule stabilization precedes axon formation. I therefore deduce that microtubules are actively involved in the process of axon formation and that local microtubule stabilization in one neuronal process is a physiological signal specifying neuronal polarization.

sad assessing initial conversely polarization gsk neurons neuronal gfp microtubules ddc:500 microtubule eb3 ddc:570

Microtubules

The Inner Workings of Cells, Winter 2008

Play Episode Listen Later Feb 25, 2008 51:26

Lecture 19: In this class, microtubule dynamics and stability and how these aspects of microtubules are controlled to produce energy and force for processes such as mitosis.

lecture cells kaplan uc antibodies molecules microtubules microtubule

Microtubule dynamics depart from the wormlike chain model

Physik - Open Access LMU - Teil 01/02

Play Episode Listen Later Jan 1, 2008

Thermal shape fluctuations of grafted microtubules were studied using high resolution particle tracking of attached fluorescent beads. First mode relaxation times were extracted from the mean square displacement in the transverse coordinate. For microtubules shorter than similar to 10 mu m, the relaxation times were found to follow an L(2) dependence instead of L(4) as expected from the standard wormlike chain model. This length dependence is shown to result from a complex length dependence of the bending stiffness which can be understood as a result of the molecular architecture of microtubules. For microtubules shorter than similar to 5 mu m, high drag coefficients indicate contributions from internal friction to the fluctuation dynamics.

model dynamics chain depart physik thermal microtubule ddc:530

Characterization of conventional kinesins Kif3 and Kif5 from Dictyostelium discoideum

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 02/06

Play Episode Listen Later Jul 27, 2007

The cellular slime mold Dictyostelium discoideum contains a total number of 13 kinesins. Two of them, kinesins Kif3 and Kif5, represent the Kinesin-1 family (formerly conventional kinesins) in D. discoideum whose members are dimeric molecular motors that move as single molecules micrometer-long distances on microtubules by using the energy from ATP hydrolysis. In this study constructs of both kinesins were expressed in E. coli, purified, and tested in biochemical assays. A GFP-fusion protein of Kif3 revealed an overall cytoplasmic localization with accumulations that could not be assigned to a specific cellular structure or vesicle. Using immunofluorescence staining an association with the endoplasmic reticulum or mitochondria was ruled out. Full-length and truncated Kif3 motors were active in gliding and ATPase assays. They showed a strong dependence on ionic strength. Like the full-length motor, the truncated Kif3-592 motor (amino acids 1-592; comprising motor domain, neck and partial stalk) reached its maximum speed of around 2.0 µms-1 at a potassium acetate concentration of 200 mM. The velocity from the microtubule-gliding assay was confirmed using kinesin labeled with Q-Dots. The shortened Kif3-342 motor (amino acids 1-342; comprising motor domain, partial neck) and the Kif3-592 construct showed an ATP turnover comparable to the fungal Nkin motor. Kif3-full-length displayed less activity in ATPase assays, possibly resulting from tail-motor inhibition. Results from the duty ratio calculations and single-molecule gliding assays indicated that Kif3 is a processive enzyme. Overall, D. discoideum’s Kif3 revealed a closer similarity to fungal rather than animal kinesins. The truncated motor Kif5-476 (amino acids 1-476; comprising motor domain, neck and partial stalk) turned out to bind microtubules, but was immotile in gliding assays. Still, this construct, as well as the shorter variant Kif5-353 (amino acids 1-353; comprising motor domain), showed activity in ATPase assays, indicating that a significant portion of the isolated protein was active. Unlike Kif3, the Kif5 motor protein was sensitive to potassium-acetate concentrations exceeding 25 mM and lost its capability to bind microtubules with increasing ionic strength. D. discoideum knockout strains showed no apparent phenotype under standard culture conditions or during development. Merely a reduced growth speed was observed in submerged cultures of kif5-null cells. A GFP-Kif5 construct showed a strong accumulation in the cell’s peripheries, in agreement with previous reports. Microtubule recovery experiments after nocodazole treatment did not reveal any significant differences between wild type and knockout strains, arguing against an influence of Kif5 on microtubule organization.

results mm conventional atp characterization gfp atpase ddc:500 microtubule kinesin dictyostelium ddc:570

Total and phosphorylated tau proteins: Evaluation as core biomarker candidates in frontotemporal dementia

Medizin - Open Access LMU - Teil 13/22

Play Episode Listen Later Jan 1, 2004

An ever increasing number of patients with neurodegenerative disorders calls for the evaluation of potential diagnostic markers that allow an early diagnosis and an early initiation of specific therapy. Clinical diagnosis of Alzheimer's disease (AD), the most common neurodegenerative disorder, reaches 80-90% accuracy upon autopsy in specialized clinical centers. Diagnosis of AD in early clinical or preclinical stages is far less accurate, as is the differential diagnosis between AD and other primary dementias, such as frontotemporal dementia (FTD). Microtubule-associated tau protein is abnormally phosphorylated in AD and aggregates as paired helical filaments in neurofibrillary tangles. Recently, immunoassays have been developed detecting tau phosphorylated at specific epitopes in cerebrospinal fluid (CSF). Four years of clinical research consistently demonstrate that CSF phosphorylated tau (p-tau) is highly increased in AD compared to healthy controls and may differentiate AD from its most relevant differential diagnoses. Tau phosphorylated at threonine 231 (p-tau(231)) shows excellent differentiation between AD and FTD, whereas serine 181 (p-tau(181)) enhances accurate differentiation between AD and dementia with Lewy bodies. Moreover, p-tau(231) levels decline with disease progression, correlating with cognitive performance at baseline. Total tau (t-tau) is regarded as a general marker of neurodegeneration for evaluation in future population-based studies. p-tau(231) and p-tau(181) yield excellent discrimination between AD and non-AD dementias including FTD, exceeding the differential diagnostic and prognostic accuracy of t-tau. Therefore, p-tau is a core biological marker candidate for future evaluation in large national and international multicenter networks. Copyright (C) 2004 S. Karger AG, Basel.

alzheimer's disease diagnosis candidates clinical evaluation medizin basel tau biomarker lewy csf ftd frontotemporal dementia copyright c microtubule karger ag tau proteins

Presence of an expressed 13-tubulin gene (TUBB) in the HLA class I region may provide the genetic basis for HLA-linked microtubule dysfunction

Biologie - Open Access LMU - Teil 02/02

Play Episode Listen Later Jan 1, 1994

An expressed beta-tubulin gene (TUBB) has previously been localized to chromosome region 6pter-p21 in man. By using a panel of deletion mutant cell lines and radiation-reduced hybrids containing fragments of chromosome 6, the TUBB locus could be mapped to the HLA class I region at 6p21.3. A long range restriction map including TUBB and several HLA class I genes was then generated by rotating field gel electrophoresis. The results show that TUBB maps to a segment 170-370 kb telomeric of HLA-C. This location suggests that a mutation at the TUBB locus could be the cause for certain forms of HLAlinked microtubule dysfunction, including immotile cilia syndrome.

class presence region basis genetic dysfunction biologie expressed hla tubb microtubule tubulin hla c

Mask, the Drosophila Ankyrin Repeat and KH domain-containing protein, regulates microtubule dynamics

Play Episode Listen Later Jan 1, 1970

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.22.056051v1?rss=1 Authors: Zhu, M., Martinez, D. A., Guidry, J. J., Majeste, N., Mao, H., Yanofsky, S., Tian, X., Wu, C. Abstract: Proper regulation of microtubule (MT) dynamics is vital for essential cellular processes and many neuronal activities, including axonal transport and synaptic growth and remodeling. Here we demonstrate that Mask negatively regulates MT stability and maintains a balanced MT length and architecture in both fly larval muscles and motor neurons. In larval muscles, loss of mask increases MT length, and altering mask genetically modifies the Tau-induced MT fragmentation. In motor neurons, loss of mask function reduces the number of End-Binding Protein 1 (EB1)-positive MT plus-ends in the axons and results in overexpansion of the presynaptic terminal at larval neuromuscular junctions (NMJ). mask shows strong genetic interaction with stathmin (stai), a neuronal modulator of MT dynamics, in regulation of axon transportation and synaptic terminal stability. The structure/function analysis on Mask suggests that Mask's action in regulating MT stability does not depend on the nucleotide-binding function of its KH domain. Furthermore, through a proteomic approach, we found that Mask physically interacts with Jupiter, an MT stabilizing factor. The MT localization of Jupiter in the axons inversely correlates with Mask levels, suggesting that Mask may modulate MT stability by inhibiting the association of Jupiter to MTs. Copy rights belong to original authors. Visit the link for more info

mt mask martinez jupiter copy dynamics protein domain mao wu kh tau tian mts guidry regulates drosophila biorxiv eb1 microtubule nmj

α- Linoleanic acid modulates phagocytosis of extracellular Tau and induces microglial migration by actin-remodeling