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Krattenmacher J, Lera-Ramirez M, Beber A, Herynek S, Grycova L, Liu X, Neuzil P, Nedelec F, Diez S, Braun M, Lansky Z. Ase1 selectively increases the lifetime of antiparallel microtubule overlaps. Curr Biol 2024:S0960-9822(24)00994-1. [PMID: 39137787 DOI: 10.1016/j.cub.2024.07.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 04/30/2024] [Accepted: 07/15/2024] [Indexed: 08/15/2024]
Abstract
Microtubules (MTs) are dynamically unstable polar biopolymers switching between periods of polymerization and depolymerization, with the switch from the polymerization to the depolymerization phase termed catastrophe and the reverse transition termed rescue.1 In presence of MT-crosslinking proteins, MTs form parallel or anti-parallel overlaps and self-assemble reversibly into complex networks, such as the mitotic spindle. Differential regulation of MT dynamics in parallel and anti-parallel overlaps is critical for the self-assembly of these networks.2,3 Diffusible MT crosslinkers of the Ase1/MAP65/PRC1 family associate with different affinities to parallel and antiparallel MT overlaps, providing a basis for this differential regulation.4,5,6,7,8,9,10,11 Ase1/MAP65/PRC1 family proteins directly affect MT dynamics12 and recruit other proteins that locally alter MT dynamics, such as CLASP or kinesin-4.7,13,14,15,16 However, how Ase1 differentially regulates MT stability in parallel and antiparallel bundles is unknown. Here, we show that Ase1 selectively promotes antiparallel MT overlap longevity by slowing down the depolymerization velocity and by increasing the rescue frequency, specifically in antiparallelly crosslinked MTs. At the retracting ends of depolymerizing MTs, concomitant with slower depolymerization, we observe retention and accumulation of Ase1 between crosslinked MTs and on isolated MTs. We hypothesize that the ability of Ase1 to reduce the dissociation of tubulin subunits is sufficient to promote its enrichment at MT ends. A mathematical model built on this idea shows good agreement with the experiments. We propose that differential regulation of MT dynamics by Ase1 contributes to mitotic spindle assembly by specifically stabilizing antiparallel overlaps, compared to parallel overlaps or isolated MTs.
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Affiliation(s)
- Jochen Krattenmacher
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czechia; B CUBE - Center of Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany; Faculty of Science, Charles University in Prague, 12800 Prague, Czech Republic
| | - Manuel Lera-Ramirez
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR144, Paris, France
| | - Alexandre Beber
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czechia
| | - Stepan Herynek
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czechia
| | - Lenka Grycova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czechia
| | - Xiaocheng Liu
- School of Mechanical Engineering, Department of Microsystem Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P.R. China
| | - Pavel Neuzil
- School of Mechanical Engineering, Department of Microsystem Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P.R. China
| | - Francois Nedelec
- Sainsbury Laboratory Cambridge, University of Cambridge, CB2 1LR Cambridge, UK.
| | - Stefan Diez
- B CUBE - Center of Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany; Cluster of Excellence Physics of Life, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Marcus Braun
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czechia.
| | - Zdenek Lansky
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czechia.
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Haque F, Subramanian R. Cytoskeleton crosstalk: Casting stable actin bundles with dynamic microtubule molds. Curr Biol 2024; 34:R72-R74. [PMID: 38262365 DOI: 10.1016/j.cub.2023.12.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Actin-microtubule crosstalk diversifies cytoskeletal networks. A new study provides insight into how the microtubule polymerase CKAP5 mediates actin-microtubule crosstalk. CKAP5 directs the assembly of stable actin bundles on dynamic microtubules; in turn, the actin bundles align growing microtubules along their length.
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Affiliation(s)
- Farah Haque
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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Ishizaka T, Hatori K. Direct observation of oriented behavior of actin filaments interacting with desmin intermediate filaments. Biochim Biophys Acta Gen Subj 2023; 1867:130488. [PMID: 37838354 DOI: 10.1016/j.bbagen.2023.130488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/03/2023] [Accepted: 10/05/2023] [Indexed: 10/16/2023]
Abstract
BACKGROUND Associations between actin filaments (AFs) and intermediate filaments (IFs) are frequently observed in living cells. The crosstalk between these cytoskeletal components underpins cellular organization and dynamics; however, the molecular basis of filamentous interactions is not fully understood. Here, we describe the mode of interaction between AFs and desmin IFs (DIFs) in a reconstituted in vitro system. METHODS AFs (rabbit skeletal muscle) and DIFs (chicken gizzard) were labeled with fluorescent dyes. DIFs were immobilized on a heavy meromyosin (HMM)-coated collodion surface. HMM-driven AFs with ATP hydrolysis was assessed in the presence of DIFs. Images of single filaments were obtained using fluorescence microscopy. Vector changes in the trajectories of single AFs were calculated from microscopy images. RESULTS AF speed transiently decreased upon contact with DIF. The difference between the incoming and outgoing angles of a moving AF broadened upon contact with a DIF. A smaller incoming angle tended to result in a smaller outgoing angle in a nematic manner. The percentage of moving AFs decreased with an increasing DIF density, but the speed of the moving AFs was similar to that in the no-desmin control. An abundance of DIFs tended to exclude AFs from the HMM-coated surfaces. CONCLUSIONS DIFs agitate the movement of AFs with the orientation. DIFs can bind to HMMs and weaken actin-myosin interactions. GENERAL SIGNIFICANCE The study indicates that apart from the binding strength, the accumulation of weak interactions characteristic of filamentous structures may affect the dynamic organization of cell architecture.
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Affiliation(s)
- Takumi Ishizaka
- Department of Mechanical Systems Engineering, Graduate School of Science and Engineering, Yamagata University, Japan
| | - Kuniyuki Hatori
- Department of Mechanical Systems Engineering, Graduate School of Science and Engineering, Yamagata University, Japan.
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Hoshino A, Clemente V, Shetty M, Castle B, Odde D, Bazzaro M. The microtubule-severing protein UNC-45A preferentially binds to curved microtubules and counteracts the microtubule-straightening effects of Taxol. J Biol Chem 2023; 299:105355. [PMID: 37858676 PMCID: PMC10654038 DOI: 10.1016/j.jbc.2023.105355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 09/28/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023] Open
Abstract
Uncoordinated protein 45A (UNC-45A) is the only known ATP-independent microtubule (MT)-severing protein. Thus, it severs MTs via a novel mechanism. In vitro and in cells, UNC-45A-mediated MT severing is preceded by the appearance of MT bends. While MTs are stiff biological polymers, in cells, they often curve, and the result of this curving can be breaking off. The contribution of MT-severing proteins on MT lattice curvature is largely undefined. Here, we show that UNC-45A curves MTs. Using in vitro biophysical reconstitution and total internal fluorescence microscopy analysis, we show that UNC-45A is enriched in the areas where MTs are curved versus the areas where MTs are straight. In cells, we show that UNC-45A overexpression increases MT curvature and its depletion has the opposite effect. We also show that this effect occurs is independent of actomyosin contractility. Lastly, we show for the first time that in cells, Paclitaxel straightens MTs, and that UNC-45A can counteracts the MT-straightening effects of the drug.
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Affiliation(s)
- Asumi Hoshino
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Valentino Clemente
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mihir Shetty
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Brian Castle
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - David Odde
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Martina Bazzaro
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA.
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Hoshino A, Clemente V, Shetty M, Castle B, Odde D, Bazzaro M. The Microtubule Severing Protein UNC-45A Counteracts the Microtubule Straightening Effects of Taxol. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557417. [PMID: 37745537 PMCID: PMC10515786 DOI: 10.1101/2023.09.12.557417] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
UNC-45A is the only known ATP-independent microtubule (MT) severing protein. Thus, it severs MTs via a novel mechanism. In vitro and in cells UNC-45A-mediated MT severing is preceded by the appearance of MT bends. While MTs are stiff biological polymers, in cells, they often curve, and the result of this curving can be breaking off. The contribution of MT severing proteins on MT lattice curvature is largely undefined. Here we show that UNC-45A curves MTs. Using in vitro biophysical reconstitution and TIRF microscopy analysis, we show that UNC-45A is enriched in the areas where MTs are curved versus the areas where MTs are straight. In cells, we show that UNC-45A overexpression increases MT curvature and its depletion has the opposite effect. We also show that this effect occurs is independent of actomyosin contractility. Lastly, we show for the first time that in cells, Paclitaxel straightens MTs, and that UNC-45A can counteracts the MT straightening effects of the drug. Significance: Our findings reveal for the first time that UNC-45A increases MT curvature. This hints that UNC-45A-mediated MT severing could be due to the worsening of MT curvature and provide a mechanistic understanding of how this MT-severing protein may act. UNC-45A is the only MT severing protein expressed in human cancers, including paclitaxel-resistant ovarian cancer. Our finding that UNC-45A counteracts the paclitaxel-straightening effects of MTs in cells suggests an additional mechanism through which cancer cells escape drug treatment.
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Li J, Szymanski DB, Kim T. Probing stress-regulated ordering of the plant cortical microtubule array via a computational approach. BMC PLANT BIOLOGY 2023; 23:308. [PMID: 37291489 DOI: 10.1186/s12870-023-04252-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/27/2023] [Indexed: 06/10/2023]
Abstract
BACKGROUND Morphological properties of tissues and organs rely on cell growth. The growth of plant cells is determined by properties of a tough outer cell wall that deforms anisotropically in response to high turgor pressure. Cortical microtubules bias the mechanical anisotropy of a cell wall by affecting the trajectories of cellulose synthases in the wall that polymerize cellulose microfibrils. The microtubule cytoskeleton is often oriented in one direction at cellular length-scales to regulate growth direction, but the means by which cellular-scale microtubule patterns emerge has not been well understood. Correlations between the microtubule orientation and tensile forces in the cell wall have often been observed. However, the plausibility of stress as a determining factor for microtubule patterning has not been directly evaluated to date. RESULTS Here, we simulated how different attributes of tensile forces in the cell wall can orient and pattern the microtubule array in the cortex. We implemented a discrete model with transient microtubule behaviors influenced by local mechanical stress in order to probe the mechanisms of stress-dependent patterning. Specifically, we varied the sensitivity of four types of dynamic behaviors observed on the plus end of microtubules - growth, shrinkage, catastrophe, and rescue - to local stress. Then, we evaluated the extent and rate of microtubule alignments in a two-dimensional computational domain that reflects the structural organization of the cortical array in plant cells. CONCLUSION Our modeling approaches reproduced microtubule patterns observed in simple cell types and demonstrated that a spatial variation in the magnitude and anisotropy of stress can mediate mechanical feedback between the wall and of the cortical microtubule array.
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Affiliation(s)
- Jing Li
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA
| | - Daniel B Szymanski
- Botany and Plant Pathology, Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN, 47907, USA.
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA.
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Wijeratne SS, Subramanian R. Real-Time Visualization of Microtubule and Protofilament-Scale Dynamics in Multi-Microtubule Arrays by Atomic Force Microscopy. Curr Protoc 2023; 3:e779. [PMID: 37227098 PMCID: PMC10439732 DOI: 10.1002/cpz1.779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Microtubules, polymers of α, β-tubulin heterodimers, are organized into multi-microtubule arrays for diverse cellular functions. The dynamic properties of microtubule arrays govern their structural and functional properties. While numerous insights into the biophysical mechanisms underlying microtubule organization have been gleaned from in vitro reconstitution studies, the assays are largely restricted to visualization of single or pairs of microtubules. Thus, the dynamic processes underlying the remodeling of multi-microtubule arrays remain poorly understood. Recent work shows that Atomic Force Microscopy (AFM) enables the visualization of nanoscale dynamics within multi-microtubule 2D arrays. In this assay, electrostatic interactions permit the non-specific adsorption of microtubule arrays to mica. AFM imaging in tapping mode, a gentle method of imaging, allows the visualization of microtubules and protofilaments without sample damage. The height information captured by AFM imaging enables the tracking of structural changes in microtubules and protofilaments within multi-microtubule arrays over time. The experimental data from the method described here reveal previously unseen modes of nanoscale dynamics in microtubule bundles formed by the microtubule-crosslinking protein PRC1 in the presence of the depolymerase MCAK. The observations demonstrate the potential of AFM imaging in transforming our understanding of the fundamental cellular process by which multi-microtubule arrays are dynamically assembled and disassembled. © 2023 Wiley Periodicals LLC. Basic Protocol: Sample preparation and real-time visualization of microtubule arrays by atomic force microscopy Alternate Protocol: Protocol for coating surface with poly-L-lysine and immobilizing microtubules.
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Affiliation(s)
- Sithara S. Wijeratne
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
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Verhey KJ, Ohi R. Causes, costs and consequences of kinesin motors communicating through the microtubule lattice. J Cell Sci 2023; 136:293511. [PMID: 36866642 PMCID: PMC10022682 DOI: 10.1242/jcs.260735] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
Microtubules are critical for a variety of important functions in eukaryotic cells. During intracellular trafficking, molecular motor proteins of the kinesin superfamily drive the transport of cellular cargoes by stepping processively along the microtubule surface. Traditionally, the microtubule has been viewed as simply a track for kinesin motility. New work is challenging this classic view by showing that kinesin-1 and kinesin-4 proteins can induce conformational changes in tubulin subunits while they are stepping. These conformational changes appear to propagate along the microtubule such that the kinesins can work allosterically through the lattice to influence other proteins on the same track. Thus, the microtubule is a plastic medium through which motors and other microtubule-associated proteins (MAPs) can communicate. Furthermore, stepping kinesin-1 can damage the microtubule lattice. Damage can be repaired by the incorporation of new tubulin subunits, but too much damage leads to microtubule breakage and disassembly. Thus, the addition and loss of tubulin subunits are not restricted to the ends of the microtubule filament but rather, the lattice itself undergoes continuous repair and remodeling. This work leads to a new understanding of how kinesin motors and their microtubule tracks engage in allosteric interactions that are critical for normal cell physiology.
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Affiliation(s)
- Kristen J. Verhey
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Author for correspondence ()
| | - Ryoma Ohi
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Bera A, Gupta ML. Microtubules in Microorganisms: How Tubulin Isotypes Contribute to Diverse Cytoskeletal Functions. Front Cell Dev Biol 2022; 10:913809. [PMID: 35865635 PMCID: PMC9294176 DOI: 10.3389/fcell.2022.913809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/15/2022] [Indexed: 11/19/2022] Open
Abstract
The cellular functions of the microtubule (MT) cytoskeleton range from relatively simple to amazingly complex. Assembled from tubulin, a heterodimeric protein with α- and β-tubulin subunits, microtubules are long, hollow cylindrical filaments with inherent polarity. They are intrinsically dynamic polymers that utilize GTP binding by tubulin, and subsequent hydrolysis, to drive spontaneous assembly and disassembly. Early studies indicated that cellular MTs are composed of multiple variants, or isotypes, of α- and β-tubulins, and that these multi-isotype polymers are further diversified by a range of posttranslational modifications (PTMs) to tubulin. These findings support the multi-tubulin hypothesis whereby individual, or combinations of tubulin isotypes possess unique properties needed to support diverse MT structures and/or cellular processes. Beginning 40 years ago researchers have sought to address this hypothesis, and the role of tubulin isotypes, by exploiting experimentally accessible, genetically tractable and functionally conserved model systems. Among these systems, important insights have been gained from eukaryotic microbial models. In this review, we illustrate how using microorganisms yielded among the earliest evidence that tubulin isotypes harbor distinct properties, as well as recent insights as to how they facilitate specific cellular processes. Ongoing and future research in microorganisms will likely continue to reveal basic mechanisms for how tubulin isotypes facilitate MT functions, along with valuable perspectives on how they mediate the range of conserved and diverse processes observed across eukaryotic microbes.
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