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Liu X, Rao L, Qiu W, Berger F, Gennerich A. Kinesin-14 HSET and KlpA are non-processive microtubule motors with load-dependent power strokes. Nat Commun 2024; 15:6564. [PMID: 39095439 PMCID: PMC11297315 DOI: 10.1038/s41467-024-50990-x] [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: 05/31/2023] [Accepted: 07/25/2024] [Indexed: 08/04/2024] Open
Abstract
Accurate chromosome segregation during cell division relies on coordinated actions of microtubule (MT)-based motor proteins in the mitotic spindle. Kinesin-14 motors play vital roles in spindle assembly and maintenance by crosslinking antiparallel MTs at the spindle midzone and anchoring spindle MTs' minus ends at the poles. In this study, we investigate the force generation and motility of the Kinesin-14 motors HSET and KlpA. Our findings reveal that both motors are non-processive, producing single load-dependent power strokes per MT encounter, with estimated load-free power strokes of ~30 and ~35 nm, respectively. Each homodimeric motor generates forces of ~0.5 pN, but when assembled in teams, they cooperate to generate forces of 1 pN or more. Notably, the cooperative activity among multiple motors leads to increased MT-sliding velocities. These results quantitatively elucidate the structure-function relationship of Kinesin-14 motors and underscore the significance of cooperative behavior in their cellular functions.
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Affiliation(s)
- Xinglei Liu
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Lu Rao
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Weihong Qiu
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, CH, Utrecht, The Netherlands
| | - Florian Berger
- Department of Biochemistry & Biophysics and Department of Physics, Oregon State University, Corvallis, OR, USA.
| | - Arne Gennerich
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA.
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2
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Salazar BM, Ohi R. Antiparallel microtubule bundling supports KIF15-driven mitotic spindle assembly. Mol Biol Cell 2024; 35:ar84. [PMID: 38598297 PMCID: PMC11238081 DOI: 10.1091/mbc.e24-01-0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 04/12/2024] Open
Abstract
The spindle is a bipolar microtubule-based machine that is crucial for accurate chromosome segregation. Spindle bipolarity is generated by Eg5 (a kinesin-5), a conserved motor that drives spindle assembly by localizing to and sliding apart antiparallel microtubules. In the presence of Eg5 inhibitors (K5Is), KIF15 (a kinesin-12) can promote spindle assembly, resulting in K5I-resistant cells (KIRCs). However, KIF15 is a less potent motor than Eg5, suggesting that other factors may contribute to spindle formation in KIRCs. Protein Regulator of Cytokinesis 1 (PRC1) preferentially bundles antiparallel microtubules, and we previously showed that PRC1 promotes KIF15-microtubule binding, leading us to hypothesize that PRC1 may enhance KIF15 activity in KIRCs. Here, we demonstrate that: 1) loss of PRC1 in KIRCs decreases spindle bipolarity, 2) overexpression of PRC1 increases spindle formation efficiency in KIRCs, 3) overexpression of PRC1 protects K5I naïve cells against the K5I S-trityl-L-cysteine (STLC), and 4) PRC1 overexpression promotes the establishment of K5I resistance. These effects are not fully reproduced by a TPX2, a microtubule bundler with no known preference for microtubule orientation. These results suggest a model wherein PRC1-mediated bundling of microtubules creates a more favorable microtubule architecture for KIF15-driven mitotic spindle assembly in the context of Eg5 inhibition.
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Affiliation(s)
- Brittany M. Salazar
- Department of Cell and Developmental Biology, University of Michigan; Ann Arbor, MI 48109
| | - Ryoma Ohi
- Department of Cell and Developmental Biology, University of Michigan; Ann Arbor, MI 48109
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3
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Laporte D, Massoni-Laporte A, Lefranc C, Dompierre J, Mauboules D, Nsamba ET, Royou A, Gal L, Schuldiner M, Gupta ML, Sagot I. A stable microtubule bundle formed through an orchestrated multistep process controls quiescence exit. eLife 2024; 12:RP89958. [PMID: 38527106 PMCID: PMC10963028 DOI: 10.7554/elife.89958] [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: 03/27/2024] Open
Abstract
Cells fine-tune microtubule assembly in both space and time to give rise to distinct edifices with specific cellular functions. In proliferating cells, microtubules are highly dynamics, and proliferation cessation often leads to their stabilization. One of the most stable microtubule structures identified to date is the nuclear bundle assembled in quiescent yeast. In this article, we characterize the original multistep process driving the assembly of this structure. This Aurora B-dependent mechanism follows a precise temporality that relies on the sequential actions of kinesin-14, kinesin-5, and involves both microtubule-kinetochore and kinetochore-kinetochore interactions. Upon quiescence exit, the microtubule bundle is disassembled via a cooperative process involving kinesin-8 and its full disassembly is required prior to cells re-entry into proliferation. Overall, our study provides the first description, at the molecular scale, of the entire life cycle of a stable microtubule structure in vivo and sheds light on its physiological function.
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Affiliation(s)
| | | | | | | | | | - Emmanuel T Nsamba
- Genetics, Development, and Cell Biology, Iowa State UniversityAmesUnited States
| | - Anne Royou
- Univ. Bordeaux, CNRS, IBGC, UMR 5095BordeauxFrance
| | - Lihi Gal
- Department of Molecular Genetics, Weizmann Institute of ScienceRehovotIsrael
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of ScienceRehovotIsrael
| | - Mohan L Gupta
- Genetics, Development, and Cell Biology, Iowa State UniversityAmesUnited States
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4
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Gao W, Lu J, Yang Z, Li E, Cao Y, Xie L. Mitotic Functions and Characters of KIF11 in Cancers. Biomolecules 2024; 14:386. [PMID: 38672404 PMCID: PMC11047945 DOI: 10.3390/biom14040386] [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: 02/07/2024] [Revised: 03/20/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024] Open
Abstract
Mitosis mediates the accurate separation of daughter cells, and abnormalities are closely related to cancer progression. KIF11, a member of the kinesin family, plays a vital role in the formation and maintenance of the mitotic spindle. Recently, an increasing quantity of data have demonstrated the upregulated expression of KIF11 in various cancers, promoting the emergence and progression of cancers. This suggests the great potential of KIF11 as a prognostic biomarker and therapeutic target. However, the molecular mechanisms of KIF11 in cancers have not been systematically summarized. Therefore, we first discuss the functions of the protein encoded by KIF11 during mitosis and connect the abnormal expression of KIF11 with its clinical significance. Then, we elucidate the mechanism of KIF11 to promote various hallmarks of cancers. Finally, we provide an overview of KIF11 inhibitors and outline areas for future work.
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Affiliation(s)
| | | | | | | | - Yufei Cao
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, China; (W.G.); (J.L.); (Z.Y.); (E.L.)
| | - Lei Xie
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, China; (W.G.); (J.L.); (Z.Y.); (E.L.)
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5
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de-Carvalho J, Tlili S, Saunders TE, Telley IA. The positioning mechanics of microtubule asters in Drosophila embryo explants. eLife 2024; 12:RP90541. [PMID: 38426416 PMCID: PMC10911390 DOI: 10.7554/elife.90541] [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: 03/02/2024] Open
Abstract
Microtubule asters are essential in localizing the action of microtubules in processes including mitosis and organelle positioning. In large cells, such as the one-cell sea urchin embryo, aster dynamics are dominated by hydrodynamic pulling forces. However, in systems with more densely positioned nuclei such as the early Drosophila embryo, which packs around 6000 nuclei within the syncytium in a crystalline-like order, it is unclear what processes dominate aster dynamics. Here, we take advantage of a cell cycle regulation Drosophila mutant to generate embryos with multiple asters, independent from nuclei. We use an ex vivo assay to further simplify this biological system to explore the forces generated by and between asters. Through live imaging, drug and optical perturbations, and theoretical modeling, we demonstrate that these asters likely generate an effective pushing force over short distances.
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Affiliation(s)
- Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste GulbenkianOeirasPortugal
| | - Sham Tlili
- Mechanobiology Institute and Department of Biological Sciences, National University of SingaporeSingaporeSingapore
| | - Timothy E Saunders
- Mechanobiology Institute and Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Institute of Molecular and Cellular Biology, A*Star, ProteosSingaporeSingapore
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of WarwickWarwickUnited Kingdom
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste GulbenkianOeirasPortugal
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6
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Wang Y, Liu YR, Wang PY, Xie P. Computational Studies Reveal How Passive Cross-Linkers Regulate Anaphase Spindle Elongation. J Phys Chem B 2024; 128:1194-1204. [PMID: 38287918 DOI: 10.1021/acs.jpcb.3c07655] [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: 01/31/2024]
Abstract
In eukaryotic cell division, a series of events are organized to produce two daughter cells. The spindle elongation in anaphase B is essential for providing enough space to maintain cell size and distribute sister chromatids properly, which is associated with microtubules and microtubule-associated proteins such as kinesin-5 Eg5 and the Ase1-related protein, PRC1. The available experimental data indicated that after the start of anaphase B more PRC1 proteins can bind to the antiparallel microtubule pairs in the spindle but the excess amount of PRC1 proteins can lead to the failure of cell division, indicating that PRC1 proteins can regulate the spindle elongation in a concentration-dependent manner. However, the underlying mechanism of the PRC1 proteins regulating the spindle elongation has not been explained up to now. Here, we use a simplified model, where only the two important participants (kinesin-5 Eg5 motors and PRC1 proteins) are considered, to study the spindle elongation during anaphase B. We first show that only in the appropriate range of the PRC1 concentration can the spindle elongation complete properly. Furthermore, we explore the underlying mechanism of PRC1 as a regulator for spindle elongation.
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Affiliation(s)
- Yao Wang
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Ru Liu
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng-Ye Wang
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Xie
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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7
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Sen A, Chowdhury D, Kunwar A. Coordination, cooperation, competition, crowding and congestion of molecular motors: Theoretical models and computer simulations. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:563-650. [PMID: 38960486 DOI: 10.1016/bs.apcsb.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Cytoskeletal motor proteins are biological nanomachines that convert chemical energy into mechanical work to carry out various functions such as cell division, cell motility, cargo transport, muscle contraction, beating of cilia and flagella, and ciliogenesis. Most of these processes are driven by the collective operation of several motors in the crowded viscous intracellular environment. Imaging and manipulation of the motors with powerful experimental probes have been complemented by mathematical analysis and computer simulations of the corresponding theoretical models. In this article, we illustrate some of the key theoretical approaches used to understand how coordination, cooperation and competition of multiple motors in the crowded intra-cellular environment drive the processes that are essential for biological function of a cell. In spite of the focus on theory, experimentalists will also find this article as an useful summary of the progress made so far in understanding multiple motor systems.
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Affiliation(s)
- Aritra Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Debashish Chowdhury
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India
| | - Ambarish Kunwar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.
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8
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Scott-Young M, Nielsen D, Riar S. Fundamentals of Mechanobiology and Potential Applications in Spinal Fusion. Int J Spine Surg 2023; 17:S61-S74. [PMID: 38135446 PMCID: PMC10753328 DOI: 10.14444/8562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND Mechanobiology can help optimize spinal fusion by providing insights into the mechanical environment required for bone healing and fusion. This includes understanding the optimal loading conditions, the mechanical properties of implanted materials, and the effects of mechanical stimuli on the cells involved in bone formation. The present article reviews the evidence for surface technologies and implant modification of spinal cages in enhancing spinal fusion. METHODS Databases used included Embase, MEDLINE, Springer, and Cochrane Library. Relevant articles were identified using specific keywords and search fields. Only systematic reviews, meta-analyses, review articles, and original research articles in English were included. Two researchers independently performed the search and selection process. A flowchart of the search strategy and study selection method is provided in the article. RESULTS The studies indicate that surface modification can significantly enhance osseointegration and interbody fusion by promoting cellular adhesion, proliferation, differentiation, and mineralization. Various surface modification techniques such as coating, etching, nanotopography, and functionalization achieve this. Similarly, implant material modification can improve implant stability, biocompatibility, and bioactivity, leading to better fusion outcomes. Mechanobiology plays a vital role in this process by influencing the cellular response to mechanical cues and promoting bone formation. CONCLUSIONS The studies reviewed indicate that surface technologies and implant material modification are promising approaches for improving the success of spinal cage fusion. Mechanobiology is critical in this process by influencing the cellular response to mechanical signals and promoting bone growth.
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Affiliation(s)
- Matthew Scott-Young
- Faculty of Health Science and Medicine, Bond University, Gold Coast, Queensland, Australia
- Gold Coast Spine, Bond University, Gold Coast, Queensland, Australia
| | - David Nielsen
- Gold Coast Spine, Bond University, Gold Coast, Queensland, Australia
| | - Sukhman Riar
- Faculty of Health Science and Medicine, Bond University, Gold Coast, Queensland, Australia
- Gold Coast Spine, Bond University, Gold Coast, Queensland, Australia
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9
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Li W, Crellin HA, Cheerambathur D, McNally FJ. Redundant microtubule crosslinkers prevent meiotic spindle bending to ensure diploid offspring in C. elegans. PLoS Genet 2023; 19:e1011090. [PMID: 38150489 PMCID: PMC10775986 DOI: 10.1371/journal.pgen.1011090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 01/09/2024] [Accepted: 12/05/2023] [Indexed: 12/29/2023] Open
Abstract
Oocyte meiotic spindles mediate the expulsion of ¾ of the genome into polar bodies to generate diploid zygotes in nearly all animal species. Failures in this process result in aneuploid or polyploid offspring that are typically inviable. Accurate meiotic chromosome segregation and polar body extrusion require the spindle to elongate while maintaining its structural integrity. Previous studies have implicated three hypothetical activities during this process, including microtubule crosslinking, microtubule sliding and microtubule polymerization. However, how these activities regulate spindle rigidity and elongation as well as the exact proteins involved in the activities remain unclear. We discovered that C. elegans meiotic anaphase spindle integrity is maintained through redundant microtubule crosslinking activities of the Kinesin-5 family motor BMK-1, the microtubule bundling protein SPD-1/PRC1, and the Kinesin-4 family motor, KLP-19. Using time-lapse imaging, we found that single depletion of KLP-19KIF4A, SPD-1PRC1 or BMK-1Eg5 had minimal effects on anaphase B spindle elongation velocity. In contrast, double depletion of SPD-1PRC1 and BMK-1Eg5 or double depletion of KLP-19KIF4A and BMK-1Eg5 resulted in spindles that elongated faster, bent in a myosin-dependent manner, and had a high rate of polar body extrusion errors. Bending spindles frequently extruded both sets of segregating chromosomes into two separate polar bodies. Normal anaphase B velocity was observed after double depletion of KLP-19KIF4A and SPD-1PRC1. These results suggest that KLP-19KIF4A and SPD-1PRC1 act in different pathways, each redundant with a separate BMK-1Eg5 pathway in regulating meiotic spindle elongation. Depletion of ZYG-8, a doublecortin-related microtubule binding protein, led to slower anaphase B spindle elongation. We found that ZYG-8DCLK1 acts by excluding SPD-1PRC1 from the spindle. Thus, three mechanistically distinct microtubule regulation modules, two based on crosslinking, and one based on exclusion of crosslinkers, power the mechanism that drives spindle elongation and structural integrity during anaphase B of C.elegans female meiosis.
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Affiliation(s)
- Wenzhe Li
- Department of Molecular and Cellular Biology, University of California, Davis, California, United States of America
| | - Helena A. Crellin
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Dhanya Cheerambathur
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Francis J. McNally
- Department of Molecular and Cellular Biology, University of California, Davis, California, United States of America
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10
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Nithianantham S, Iwanski MK, Gaska I, Pandey H, Bodrug T, Inagaki S, Major J, Brouhard GJ, Gheber L, Rosenfeld SS, Forth S, Hendricks AG, Al-Bassam J. The kinesin-5 tail and bipolar minifilament domains are the origin of its microtubule crosslinking and sliding activity. Mol Biol Cell 2023; 34:ar111. [PMID: 37610838 PMCID: PMC10559304 DOI: 10.1091/mbc.e23-07-0287] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/07/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023] Open
Abstract
Kinesin-5 crosslinks and slides apart microtubules to assemble, elongate, and maintain the mitotic spindle. Kinesin-5 is a tetramer, where two N-terminal motor domains are positioned at each end of the motor, and the coiled-coil stalk domains are organized into a tetrameric bundle through the bipolar assembly (BASS) domain. To dissect the function of the individual structural elements of the motor, we constructed a minimal kinesin-5 tetramer (mini-tetramer). We determined the x-ray structure of the extended, 34-nm BASS domain. Guided by these structural studies, we generated active bipolar kinesin-5 mini-tetramer motors from Drosophila melanogastor and human orthologues which are half the length of native kinesin-5. We then used these kinesin-5 mini-tetramers to examine the role of two unique structural adaptations of kinesin-5: 1) the length and flexibility of the tetramer, and 2) the C-terminal tails which interact with the motor domains to coordinate their ATPase activity. The C-terminal domain causes frequent pausing and clustering of kinesin-5. By comparing microtubule crosslinking and sliding by mini-tetramer and full-length kinesin-5, we find that both the length and flexibility of kinesin-5 and the C-terminal tails govern its ability to crosslink microtubules. Once crosslinked, stiffer mini-tetramers slide antiparallel microtubules more efficiently than full-length motors.
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Affiliation(s)
- Stanley Nithianantham
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Malina K. Iwanski
- Departments of Biology and Bioengineering, McGill University, Montreal, Quebec Canada H3A 1B1
| | - Ignas Gaska
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Himanshu Pandey
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Tatyana Bodrug
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Sayaka Inagaki
- Department of Pharmacology, Mayo Clinic, Jacksonville, FL 32224
| | - Jennifer Major
- Department of Pharmacology, Mayo Clinic, Jacksonville, FL 32224
| | - Gary J. Brouhard
- Departments of Biology and Bioengineering, McGill University, Montreal, Quebec Canada H3A 1B1
| | - Larissa Gheber
- Department of Chemistry, The Ben Gurion University, Ber Sheva, Israel
| | | | - Scott Forth
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Adam G. Hendricks
- Departments of Biology and Bioengineering, McGill University, Montreal, Quebec Canada H3A 1B1
| | - Jawdat Al-Bassam
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
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11
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Gergely ZR, Jones MH, Zhou B, Cash C, McIntosh JR, Betterton MD. Distinct regions of the kinesin-5 C-terminal tail are essential for mitotic spindle midzone localization and sliding force. Proc Natl Acad Sci U S A 2023; 120:e2306480120. [PMID: 37725645 PMCID: PMC10523502 DOI: 10.1073/pnas.2306480120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/05/2023] [Indexed: 09/21/2023] Open
Abstract
Kinesin-5 motor proteins play essential roles during mitosis in most organisms. Their tetrameric structure and plus-end-directed motility allow them to bind to and move along antiparallel microtubules, thereby pushing spindle poles apart to assemble a bipolar spindle. Recent work has shown that the C-terminal tail is particularly important to kinesin-5 function: The tail affects motor domain structure, ATP hydrolysis, motility, clustering, and sliding force measured for purified motors, as well as motility, clustering, and spindle assembly in cells. Because previous work has focused on presence or absence of the entire tail, the functionally important regions of the tail remain to be identified. We have therefore characterized a series of kinesin-5/Cut7 tail truncation alleles in fission yeast. Partial truncation causes mitotic defects and temperature-sensitive growth, while further truncation that removes the conserved BimC motif is lethal. We compared the sliding force generated by cut7 mutants using a kinesin-14 mutant background in which some microtubules detach from the spindle poles and are pushed into the nuclear envelope. These Cut7-driven protrusions decreased as more of the tail was truncated, and the most severe truncations produced no observable protrusions. Our observations suggest that the C-terminal tail of Cut7p contributes to both sliding force and midzone localization. In the context of sequential tail truncation, the BimC motif and adjacent C-terminal amino acids are particularly important for sliding force. In addition, moderate tail truncation increases midzone localization, but further truncation of residues N-terminal to the BimC motif decreases midzone localization.
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Affiliation(s)
- Zachary R Gergely
- Department of Physics, University of Colorado, Boulder, CO 80309
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Michele H Jones
- Department of Physics, University of Colorado, Boulder, CO 80309
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Bojun Zhou
- Department of Physics, University of Colorado, Boulder, CO 80309
| | - Cai Cash
- Department of Physics, University of Colorado, Boulder, CO 80309
| | - J Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Meredith D Betterton
- Department of Physics, University of Colorado, Boulder, CO 80309
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309
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12
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Gergely Z, Jones MH, Zhou B, Cash C, McIntosh R, Betterton M. Distinct regions of the kinesin-5 C-terminal tail are essential for mitotic spindle midzone localization and sliding force. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.01.538972. [PMID: 37205432 PMCID: PMC10187184 DOI: 10.1101/2023.05.01.538972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Kinesin-5 motor proteins play essential roles during mitosis in most organisms. Their tetrameric structure and plus-end-directed motility allow them to bind to and move along antiparallel microtubules, thereby pushing spindle poles apart to assemble a bipolar spindle. Recent work has shown that the C-terminal tail is particularly important to kinesin-5 function: the tail affects motor domain structure, ATP hydrolysis, motility, clustering, and sliding force measured for purified motors, as well as motility, clustering, and spindle assembly in cells. Because previous work has focused on presence or absence of the entire tail, the functionally important regions of the tail remain to be identified. We have therefore characterized a series of kinesin-5/Cut7 tail truncation alleles in fission yeast. Partial truncation causes mitotic defects and temperature-sensitive growth, while further truncation that removes the conserved BimC motif is lethal. We compared the sliding force generated by cut7 mutants using a kinesin-14 mutant background in which some microtubules detach from the spindle poles and are pushed into the nuclear envelope. These Cut7-driven protrusions decreased as more of the tail was truncated, and the most severe truncations produced no observable protrusions. Our observations suggest that the C-terminal tail of Cut7p contributes to both sliding force and midzone localization. In the context of sequential tail truncation, the BimC motif and adjacent C-terminal amino acids are particularly important for sliding force. In addition, moderate tail truncation increases midzone localization, but further truncation of residues N terminal to the BimC motif decreases midzone localization.
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13
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Liu X, Rao L, Qiu W, Gennerich A. Kinesin-14 HSET and KlpA are non-processive microtubule motors with load-dependent power strokes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.09.544415. [PMID: 37333225 PMCID: PMC10274885 DOI: 10.1101/2023.06.09.544415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Accurate chromosome segregation during cell division relies on coordinated actions of microtubule (MT)-based motor proteins in the mitotic spindle. Kinesin-14 motors play vital roles in spindle assembly and maintenance by crosslinking antiparallel MTs at the spindle midzone and anchoring spindle MTs' minus ends at the poles. We investigate the force generation and motility of the Kinesin-14 motors HSET and KlpA, revealing that both motors function as non-processive motors under load, producing single power strokes per MT encounter. Each homodimeric motor generates forces of ∼0.5 pN, but when assembled in teams, they cooperate to generate forces of 1 pN or more. Importantly, cooperative activity among multiple motors leads to increased MT-sliding velocities. Our findings deepen our understanding of the structure-function relationship of Kinesin-14 motors and underscore the significance of cooperative behavior in their cellular functions.
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14
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Geyer VF, Diez S. Horizontal Magnetic Tweezers to Directly Measure the Force-Velocity Relationship for Multiple Kinesin Motors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2300558. [PMID: 37035988 DOI: 10.1002/smll.202300558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/11/2023] [Indexed: 06/19/2023]
Abstract
Transport of intracellular cargo along cytoskeletal filaments is often achieved by the concerted action of multiple motor molecules. While single-molecule studies have provided profound insight into the mechano-chemical principles and force generation of individual motors, studies on multi-motor systems are less advanced. Here, a horizontal magnetic-tweezers setup is applied, capable of producing up to 150 pN of horizontal force onto 2.8 µm superparamagnetic beads, to motor-propelled cytoskeletal filaments. It is found that kinesin-1 driven microtubules decorated with individual beads display frequent transitions in their gliding velocities which we attribute to dynamic changes in the number of engaged motors. Applying defined temporal force-ramps the force-velocity relationship is directly measured for multi-motor transport. It is found that the stall forces of individual motors are approximately additive and collective backward motion of the transport system under super-stall forces is observed. The magnetic-tweezers apparatus is expected to be readily applicable to a wide range of molecular and cellular motility assays.
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Affiliation(s)
- Veikko F Geyer
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Tatzberg 41, 01307, Dresden, Germany
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Tatzberg 41, 01307, Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, Arnoldstraße 18, 01307, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
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15
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Gergely ZR, Ansari S, Jones MH, Zhou B, Cash C, McIntosh R, Betterton MD. The kinesin-5 protein Cut7 moves bidirectionally on fission yeast spindles with activity that increases in anaphase. J Cell Sci 2023; 136:jcs260474. [PMID: 36655493 PMCID: PMC10112985 DOI: 10.1242/jcs.260474] [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: 08/16/2022] [Accepted: 01/10/2023] [Indexed: 01/20/2023] Open
Abstract
Kinesin-5 motors are essential to separate mitotic spindle poles and assemble a bipolar spindle in many organisms. These motors crosslink and slide apart antiparallel microtubules via microtubule plus-end-directed motility. However, kinesin-5 localization is enhanced away from antiparallel overlaps. Increasing evidence suggests this localization occurs due to bidirectional motility or trafficking. The purified fission-yeast kinesin-5 protein Cut7 moves bidirectionally, but bidirectionality has not been shown in cells, and the function of the minus-end-directed movement is unknown. Here, we characterized the motility of Cut7 on bipolar and monopolar spindles and observed movement toward both plus- and minus-ends of microtubules. Notably, the activity of the motor increased at anaphase B onset. Perturbations to microtubule dynamics only modestly changed Cut7 movement, whereas Cut7 mutation reduced movement. These results suggest that the directed motility of Cut7 contributes to the movement of the motor. Comparison of the Cut7 mutant and human Eg5 (also known as KIF11) localization suggest a new hypothesis for the function of minus-end-directed motility and spindle-pole localization of kinesin-5s.
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Affiliation(s)
- Zachary R. Gergely
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Saad Ansari
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Michele H. Jones
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Bojun Zhou
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Cai Cash
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Meredith D. Betterton
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
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16
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Yu WX, Li YK, Xu MF, Xu CJ, Chen J, Wei YL, She ZY. Kinesin-5 Eg5 is essential for spindle assembly, chromosome stability and organogenesis in development. Cell Death Dis 2022; 8:490. [PMID: 36513626 DOI: 10.1038/s41420-022-01281-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022]
Abstract
Chromosome stability relies on bipolar spindle assembly and faithful chromosome segregation during cell division. Kinesin-5 Eg5 is a plus-end-directed kinesin motor protein, which is essential for spindle pole separation and chromosome alignment in mitosis. Heterozygous Eg5 mutations cause autosomal-dominant microcephaly, primary lymphedema, and chorioretinal dysplasia syndrome in humans. However, the developmental roles and cellular mechanisms of Eg5 in organogenesis remain largely unknown. In this study, we have shown that Eg5 inhibition leads to the formation of the monopolar spindle, chromosome misalignment, polyploidy, and subsequent apoptosis. Strikingly, long-term inhibition of Eg5 stimulates the immune responses and the accumulation of lymphocytes in the mouse spleen through the innate and specific immunity pathways. Eg5 inhibition results in metaphase arrest and cell growth inhibition, and suppresses the formation of somite and retinal development in zebrafish embryos. Our data have revealed the essential roles of kinesin-5 Eg5 involved in cell proliferation, chromosome stability, and organogenesis during development. Our findings shed a light on the cellular basis and pathogenesis in microcephaly, primary lymphedema, and chorioretinal dysplasia syndrome of Eg5-mutation-positive patients.
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Affiliation(s)
- Wen-Xin Yu
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, 350122, Fuzhou, Fujian, China.,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, 350122, Fuzhou, Fujian, China
| | - Yu-Kun Li
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, 350122, Fuzhou, Fujian, China.,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, 350122, Fuzhou, Fujian, China
| | - Meng-Fei Xu
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, 350122, Fuzhou, Fujian, China.,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, 350122, Fuzhou, Fujian, China
| | - Chen-Jie Xu
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, 350122, Fuzhou, Fujian, China.,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, 350122, Fuzhou, Fujian, China
| | - Jie Chen
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, 350122, Fuzhou, Fujian, China.,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, 350122, Fuzhou, Fujian, China
| | - Ya-Lan Wei
- Medical Research Center, Fujian Maternity and Child Health Hospital, 350001, Fuzhou, Fujian, China.,College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, 350122, Fuzhou, Fujian, China
| | - Zhen-Yu She
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, 350122, Fuzhou, Fujian, China. .,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, 350122, Fuzhou, Fujian, China.
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17
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Morphological growth dynamics, mechanical stability, and active microtubule mechanics underlying spindle self-organization. Proc Natl Acad Sci U S A 2022; 119:e2209053119. [PMID: 36282919 PMCID: PMC9636915 DOI: 10.1073/pnas.2209053119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The spindle is a dynamic intracellular structure self-organized from microtubules and microtubule-associated proteins. The spindle’s bipolar morphology is essential for the faithful segregation of chromosomes during cell division, and it is robustly maintained by multifaceted mechanisms. However, abnormally shaped spindles, such as multipolar spindles, can stochastically arise in a cell population and cause chromosome segregation errors. The physical basis of how microtubules fail in bipolarization and occasionally favor nonbipolar assembly is poorly understood. Here, using live fluorescence imaging and quantitative shape analysis in
Xenopus
egg extracts, we find that spindles of varied shape morphologies emerge through nonrandom, bistable self-organization paths, one leading to a bipolar and the other leading to a multipolar phenotype. The bistability defines the spindle’s unique morphological growth dynamics linked to each shape phenotype and can be promoted by a locally distorted microtubule flow that arises within premature structures. We also find that bipolar and multipolar spindles are stable at the steady-state in bulk but can infrequently switch between the two phenotypes. Our microneedle-based physical manipulation further demonstrates that a transient force perturbation applied near the assembled pole can trigger the phenotypic switching, revealing the mechanical plasticity of the spindle. Together with molecular perturbation of kinesin-5 and augmin, our data propose the physical and molecular bases underlying the emergence of spindle-shape variation, which influences chromosome segregation fidelity during cell division.
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18
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Favre-Bulle IA, Scott EK. Optical tweezers across scales in cell biology. Trends Cell Biol 2022; 32:932-946. [PMID: 35672197 PMCID: PMC9588623 DOI: 10.1016/j.tcb.2022.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 01/21/2023]
Abstract
Optical tweezers (OT) provide a noninvasive approach for delivering minute physical forces to targeted objects. Controlling such forces in living cells or in vitro preparations allows for the measurement and manipulation of numerous processes relevant to the form and function of cells. As such, OT have made important contributions to our understanding of the structures of proteins and nucleic acids, the interactions that occur between microscopic structures within cells, the choreography of complex processes such as mitosis, and the ways in which cells interact with each other. In this review, we highlight recent contributions made to the field of cell biology using OT and provide basic descriptions of the physics, the methods, and the equipment that made these studies possible.
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Affiliation(s)
- Itia A Favre-Bulle
- Queensland Brain Institute, The University of Queensland, 4067, Brisbane, Australia; School of Mathematics and Physics, The University of Queensland, 4067, Brisbane, Australia.
| | - Ethan K Scott
- Queensland Brain Institute, The University of Queensland, 4067, Brisbane, Australia; Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
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19
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Risteski P, Božan D, Jagrić M, Bosilj A, Pavin N, Tolić IM. Length-dependent poleward flux of sister kinetochore fibers promotes chromosome alignment. Cell Rep 2022; 40:111169. [PMID: 35926461 PMCID: PMC9364240 DOI: 10.1016/j.celrep.2022.111169] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/20/2022] [Accepted: 07/14/2022] [Indexed: 11/25/2022] Open
Abstract
Chromosome alignment at the spindle equator promotes proper chromosome segregation and depends on pulling forces exerted at kinetochore fiber tips together with polar ejection forces. However, kinetochore fibers are also subjected to forces driving their poleward flux. Here we introduce a flux-driven centering model that relies on flux generated by forces within the overlaps of bridging and kinetochore fibers. This centering mechanism works so that the longer kinetochore fiber fluxes faster than the shorter one, moving the kinetochores toward the center. We develop speckle microscopy in human spindles and confirm the key prediction that kinetochore fiber flux is length dependent. Kinetochores are better centered when overlaps are shorter and the kinetochore fiber flux slower than the bridging fiber flux. We identify Kif18A and Kif4A as overlap and flux regulators and NuMA as a fiber coupler. Thus, length-dependent sliding forces exerted by the bridging fiber onto kinetochore fibers support chromosome alignment. A flux-driven centering model explains chromosome alignment at the spindle equator Kinetochore fiber poleward flux is driven by overlap microtubules Kinetochore centering requires faster flux of the longer sister kinetochore fiber Chromosome alignment depends on the overlap length of bridging microtubules
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Affiliation(s)
- Patrik Risteski
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Domagoj Božan
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia
| | - Mihaela Jagrić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Agneza Bosilj
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia
| | - Nenad Pavin
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia.
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
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20
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Kiewisz R, Fabig G, Conway W, Baum D, Needleman DJ, Müller-Reichert T. Three-dimensional structure of kinetochore-fibers in human mitotic spindles. eLife 2022; 11:75459. [PMID: 35894209 PMCID: PMC9365394 DOI: 10.7554/elife.75459] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 07/24/2022] [Indexed: 11/13/2022] Open
Abstract
During cell division, kinetochore microtubules (KMTs) provide a physical linkage between the chromosomes and the rest of the spindle. KMTs in mammalian cells are organized into bundles, so-called kinetochore-fibers (k-fibers), but the ultrastructure of these fibers is currently not well characterized. Here, we show by large-scale electron tomography that each k-fiber in HeLa cells in metaphase is composed of approximately nine KMTs, only half of which reach the spindle pole. Our comprehensive reconstructions allowed us to analyze the three-dimensional (3D) morphology of k-fibers and their surrounding MTs in detail. We found that k-fibers exhibit remarkable variation in circumference and KMT density along their length, with the pole-proximal side showing a broadening. Extending our structural analysis then to other MTs in the spindle, we further observed that the association of KMTs with non-KMTs predominantly occurs in the spindle pole regions. Our 3D reconstructions have implications for KMT growth and k-fiber self-organization models as covered in a parallel publication applying complementary live-cell imaging in combination with biophysical modeling (Conway et al., 2022). Finally, we also introduce a new visualization tool allowing an interactive display of our 3D spindle data that will serve as a resource for further structural studies on mitosis in human cells.
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Affiliation(s)
- Robert Kiewisz
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Gunar Fabig
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - William Conway
- Department of Physics, Harvard University, Cambridge, United States
| | - Daniel Baum
- Department of Visual and Data-Centric Computing, Zuse Institute Berlin, Berlin, Germany
| | - Daniel J Needleman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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21
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Palumbo J, Tai E, Forth S. Directly Measuring Forces within Reconstituted Active Microtubule Bundles. J Vis Exp 2022:10.3791/63819. [PMID: 35635475 PMCID: PMC10790399 DOI: 10.3791/63819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023] Open
Abstract
Microtubule networks are employed in cells to accomplish a wide range of tasks, ranging from acting as tracks for vesicle transport to working as specialized arrays during mitosis to regulate chromosome segregation. Proteins that interact with microtubules include motors such as kinesins and dynein, which can generate active forces and directional motion, as well as non-motor proteins that crosslink filaments into higher-order networks or regulate filament dynamics. To date, biophysical studies of microtubule-associated proteins have overwhelmingly focused on the role of single motor proteins needed for vesicle transport, and significant progress has been made in elucidating the force-generating properties and mechanochemical regulation of kinesins and dyneins. However, for processes in which microtubules act both as cargo and track, such as during filament sliding within the mitotic spindle, much less is understood about the biophysical regulation of ensembles of the crosslinking proteins involved. Here, we detail our methodology for directly probing force generation and response within crosslinked microtubule minimal networks reconstituted from purified microtubules and mitotic proteins. Microtubule pairs are crosslinked by proteins of interest, one microtubule is immobilized to a microscope coverslip, and the second microtubule is manipulated by an optical trap. Simultaneous total internal reflection fluorescence microscopy allows for multichannel visualization of all the components of this microtubule network as the filaments slide apart to generate force. We also demonstrate how these techniques can be used to probe pushing forces exerted by kinesin-5 ensembles and how viscous braking forces arise between sliding microtubule pairs crosslinked by the mitotic MAP PRC1. These assays provide insights into the mechanisms of spindle assembly and function and can be more broadly adapted to study dense microtubule network mechanics in diverse contexts, such as the axon and dendrites of neurons and polar epithelial cells.
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Affiliation(s)
- Jacob Palumbo
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute
| | - Ellinor Tai
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute
| | - Scott Forth
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute;
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22
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She ZY, Zhong N, Wei YL. Kinesin-5 Eg5 mediates centrosome separation to control spindle assembly in spermatocytes. Chromosoma 2022; 131:87-105. [PMID: 35437661 DOI: 10.1007/s00412-022-00772-5] [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: 12/02/2021] [Revised: 03/12/2022] [Accepted: 04/08/2022] [Indexed: 11/25/2022]
Abstract
Timely and accurate centrosome separation is critical for bipolar spindle organization and faithful chromosome segregation during cell division. Kinesin-5 Eg5 is essential for centrosome separation and spindle organization in somatic cells; however, the detailed functions and mechanisms of Eg5 in spermatocytes remain unclear. In this study, we show that Eg5 proteins are located at spindle microtubules and centrosomes in spermatocytes both in vivo and in vitro. We reveal that the spermatocytes are arrested at metaphase I in seminiferous tubules after Eg5 inhibition. Eg5 ablation results in cell cycle arrest, the formation of monopolar spindle, and chromosome misalignment in cultured GC-2 spd cells. Importantly, we find that the long-term inhibition of Eg5 results in an increased number of centrosomes and chromosomal instability in spermatocytes. Our findings indicate that Eg5 mediates centrosome separation to control spindle assembly and chromosome alignment in spermatocytes, which finally contribute to chromosome stability and faithful cell division of the spermatocytes.
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Affiliation(s)
- Zhen-Yu She
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, Fujian, China.
- Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, 350122, Fujian, China.
| | - Ning Zhong
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, Fujian, China
- Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, 350122, Fujian, China
| | - Ya-Lan Wei
- Fujian Obstetrics and Gynecology Hospital, Fuzhou, 350011, Fujian, China
- Medical Research Center, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, 350001, Fujian, China
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23
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Mani N, Marchan MF, Subramanian R. Simultaneous Visualization of the Dynamics of Crosslinked and Single Microtubules In Vitro by TIRF Microscopy. JOURNAL OF VISUALIZED EXPERIMENTS : JOVE 2022:10.3791/63377. [PMID: 35253794 PMCID: PMC9914519 DOI: 10.3791/63377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Microtubules are polymers of αβ-tubulin heterodimers that organize into distinct structures in cells. Microtubule-based architectures and networks often contain subsets of microtubule arrays that differ in their dynamic properties. For example, in dividing cells, stable bundles of crosslinked microtubules coexist in close proximity to dynamic non-crosslinked microtubules. TIRF-microscopy-based in vitro reconstitution studies enable the simultaneous visualization of the dynamics of these different microtubule arrays. In this assay, an imaging chamber is assembled with surface-immobilized microtubules, which are either present as single filaments or organized into crosslinked bundles. Introduction of tubulin, nucleotides, and protein regulators allows direct visualization of associated proteins and of dynamic properties of single and crosslinked microtubules. Furthermore, changes that occur as dynamic single microtubules organize into bundles can be monitored in real-time. The method described here allows for a systematic evaluation of the activity and localization of individual proteins, as well as synergistic effects of protein regulators on two different microtubule subsets under identical experimental conditions, thereby providing mechanistic insights that are inaccessible by other methods.
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Affiliation(s)
- Nandini Mani
- Molecular Biology, Massachusetts General Hospital,Department of Genetics, Harvard Medical School
| | | | - Radhika Subramanian
- Molecular Biology, Massachusetts General Hospital; Department of Genetics, Harvard Medical School;
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24
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Guo W, Sun S, Sanchez JE, Lopez-Hernandez AE, Ale TA, Chen J, Afrin T, Qiu W, Xie Y, Li L. Using a comprehensive approach to investigate the interaction between Kinesin-5/Eg5 and the microtubule. Comput Struct Biotechnol J 2022; 20:4305-4314. [PMID: 36051882 PMCID: PMC9396395 DOI: 10.1016/j.csbj.2022.08.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 08/01/2022] [Accepted: 08/08/2022] [Indexed: 01/02/2023] Open
Abstract
Kinesins are microtubule-based motor proteins that play important roles ranging from intracellular transport to cell division. Human Kinesin-5 (Eg5) is essential for mitotic spindle assembly during cell division. By combining molecular dynamics (MD) simulations with other multi-scale computational approaches, we systematically studied the interaction between Eg5 and the microtubule. We find the electrostatic feature on the motor domains of Eg5 provides attractive interactions to the microtubule. Additionally, the folding and binding energy analysis reveals that the Eg5 motor domain performs its functions best when in a weak acidic environment. Molecular dynamics analyses of hydrogen bonds and salt bridges demonstrate that, on the binding interfaces of Eg5 and the tubulin heterodimer, salt bridges play the most significant role in holding the complex. The salt bridge residues on the binding interface of Eg5 are mostly positive, while salt bridge residues on the binding interface of tubulin heterodimer are mostly negative. Such salt bridge residue distribution is consistent with electrostatic potential calculations. In contrast, the interface between α and β-tubulins is dominated by hydrogen bonds rather than salt bridges. Compared to the Eg5/α-tubulin interface, the Eg5/β-tubulin interface has a greater number of salt bridges and higher occupancy for salt bridges. This asymmetric salt bridge distribution may play a significant role in Eg5′s directionality. The residues involved in hydrogen bonds and salt bridges are identified in this work and may be helpful for anticancer drug design.
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Affiliation(s)
- Wenhan Guo
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | - Shengjie Sun
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | - Jason E. Sanchez
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | | | - Tolulope A. Ale
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | - Jiawei Chen
- Department of Physics, University of Texas at El Paso, El Paso, TX, USA
| | - Tanjina Afrin
- Department of Physics, University of Texas at El Paso, El Paso, TX, USA
- Department of Physics, Oregon State University, Corvallis, OR, USA
| | - Weihong Qiu
- Department of Physics, Oregon State University, Corvallis, OR, USA
| | - Yixin Xie
- Department of Information Technology, Kennesaw State University, Kennesaw, GA, USA
| | - Lin Li
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
- Department of Physics, University of Texas at El Paso, El Paso, TX, USA
- Corresponding author.
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25
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Neahring L, Cho NH, Dumont S. Opposing motors provide mechanical and functional robustness in the human spindle. Dev Cell 2021; 56:3006-3018.e5. [PMID: 34614397 DOI: 10.1016/j.devcel.2021.09.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/27/2021] [Accepted: 09/13/2021] [Indexed: 11/30/2022]
Abstract
At each cell division, the spindle self-organizes from microtubules and motors. In human spindles, the motors dynein and Eg5 generate contractile and extensile stress, respectively. Inhibiting dynein or its targeting factor NuMA leads to unfocused, turbulent spindles, and inhibiting Eg5 leads to monopoles; yet, bipolar spindles form when both are inhibited together. What, then, are the roles of these opposing motors? Here, we generate NuMA/dynein- and Eg5-doubly inhibited spindles that not only attain a typical metaphase shape and size but also undergo anaphase. However, these spindles have reduced microtubule dynamics and are mechanically fragile, fracturing under force. Furthermore, they exhibit lagging chromosomes and a dramatic left-handed twist at anaphase. Thus, although these opposing motors are not required for spindle shape, they are essential to its mechanical and functional robustness. This work suggests a design principle whereby opposing active stresses provide robustness to force-generating cellular structures.
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Affiliation(s)
- Lila Neahring
- Department of Bioengineering & Therapeutic Sciences, UCSF, San Francisco, CA 94158, USA; Developmental & Stem Cell Biology Graduate Program, UCSF, San Francisco, CA 94143, USA.
| | - Nathan H Cho
- Department of Bioengineering & Therapeutic Sciences, UCSF, San Francisco, CA 94158, USA; Tetrad Graduate Program, UCSF, San Francisco, CA 94158, USA
| | - Sophie Dumont
- Department of Bioengineering & Therapeutic Sciences, UCSF, San Francisco, CA 94158, USA; Developmental & Stem Cell Biology Graduate Program, UCSF, San Francisco, CA 94143, USA; Tetrad Graduate Program, UCSF, San Francisco, CA 94158, USA; Department of Biochemistry & Biophysics, UCSF, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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26
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Cook AD, Roberts AJ, Atherton J, Tewari R, Topf M, Moores CA. Cryo-EM structure of a microtubule-bound parasite kinesin motor and implications for its mechanism and inhibition. J Biol Chem 2021; 297:101063. [PMID: 34375637 PMCID: PMC8526983 DOI: 10.1016/j.jbc.2021.101063] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/23/2021] [Accepted: 08/05/2021] [Indexed: 11/25/2022] Open
Abstract
Plasmodium parasites cause malaria and are responsible annually for hundreds of thousands of deaths. Kinesins are a superfamily of microtubule-dependent ATPases that play important roles in the parasite replicative machinery, which is a potential target for antiparasite drugs. Kinesin-5, a molecular motor that cross-links microtubules, is an established antimitotic target in other disease contexts, but its mechanism in Plasmodium falciparum is unclear. Here, we characterized P. falciparum kinesin-5 (PfK5) using cryo-EM to determine the motor's nucleotide-dependent microtubule-bound structure and introduced 3D classification of individual motors into our microtubule image processing pipeline to maximize our structural insights. Despite sequence divergence in PfK5, the motor exhibits classical kinesin mechanochemistry, including ATP-induced subdomain rearrangement and cover neck bundle formation, consistent with its plus-ended directed motility. We also observed that an insertion in loop5 of the PfK5 motor domain creates a different environment in the well-characterized human kinesin-5 drug-binding site. Our data reveal the possibility for selective inhibition of PfK5 and can be used to inform future exploration of Plasmodium kinesins as antiparasite targets.
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Affiliation(s)
- Alexander D Cook
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Anthony J Roberts
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Joseph Atherton
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Rita Tewari
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Maya Topf
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, United Kingdom.
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27
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The Arabidopsis thaliana Kinesin-5 AtKRP125b Is a Processive, Microtubule-Sliding Motor Protein with Putative Plant-Specific Functions. Int J Mol Sci 2021; 22:ijms222111361. [PMID: 34768803 PMCID: PMC8583919 DOI: 10.3390/ijms222111361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/02/2022] Open
Abstract
The formation and maintenance of the mitotic spindle during cell division requires several microtubule-interacting motor proteins. Members of the kinesin-5 family play an essential role in the bipolar organization of the spindle. These highly conserved, homotetrameric proteins cross-link anti-parallel microtubules and slide them apart to elongate the spindle during the equal separation of chromosomes. Whereas vertebrate kinesin-5 proteins are well studied, knowledge about the biochemical properties and the function of plant kinesin-5 proteins is still limited. Here, we characterized the properties of AtKRP125b, one of four kinesin-5 proteins in Arabidopsis thaliana. In in vitro motility assays, AtKRP125b displayed the archetypal characteristics of a kinesin-5 protein, a low velocity of about 20 nm·s−1, and a plus end-directed, processive movement. Moreover, AtKRP125b was able to cross-link microtubules and to slide them apart, as required for developing and maintaining the mitotic spindle. In line with such a function, GFP-AtKRP125b fusion proteins were predominantly detected in the nucleus when expressed in Arabidopsis thaliana leaf protoplasts or Nicotiana benthamiana epidermis cells and analyzed by confocal microscopy. However, we also detected GFP signals in the cytoplasm, suggesting additional functions. By generating and analyzing AtKRP125b promoter-reporter lines, we showed that the AtKRP125b promoter was active in the vascular tissue of roots, lateral roots, cotyledons, and true leaves. Remarkably, we could not detect promoter activity in meristematic tissues. Taken together, our biochemical data support a role of AtKRP125b in mitosis, but it may also have additional functions outside the nucleus and during interphase.
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28
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Fong KK, Davis TN, Asbury CL. Microtubule pivoting enables mitotic spindle assembly in S. cerevisiae. J Cell Biol 2021; 220:211686. [PMID: 33464308 PMCID: PMC7814349 DOI: 10.1083/jcb.202007193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 12/17/2022] Open
Abstract
To assemble a bipolar spindle, microtubules emanating from two poles must bundle into an antiparallel midzone, where plus end–directed motors generate outward pushing forces to drive pole separation. Midzone cross-linkers and motors display only modest preferences for antiparallel filaments, and duplicated poles are initially tethered together, an arrangement that instead favors parallel interactions. Pivoting of microtubules around spindle poles might help overcome this geometric bias, but the intrinsic pivoting flexibility of the microtubule–pole interface has not been directly measured, nor has its importance during early spindle assembly been tested. By measuring the pivoting of microtubules around isolated yeast spindle poles, we show that pivoting flexibility can be modified by mutating a microtubule-anchoring pole component, Spc110. By engineering mutants with different flexibilities, we establish the importance of pivoting in vivo for timely pole separation. Our results suggest that passive thermal pivoting can bring microtubules from side-by-side poles into initial contact, but active minus end–directed force generation will be needed to achieve antiparallel alignment.
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Affiliation(s)
- Kimberly K Fong
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Trisha N Davis
- Department of Biochemistry, University of Washington, Seattle, WA
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
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29
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Biswas A, Kim K, Cojoc G, Guck J, Reber S. The Xenopus spindle is as dense as the surrounding cytoplasm. Dev Cell 2021; 56:967-975.e5. [PMID: 33823135 DOI: 10.1016/j.devcel.2021.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/11/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022]
Abstract
The mitotic spindle is a self-organizing molecular machine, where hundreds of different molecules continuously interact to maintain a dynamic steady state. While our understanding of key molecular players in spindle assembly is significant, it is still largely unknown how the spindle's material properties emerge from molecular interactions. Here, we use correlative fluorescence imaging and label-free three-dimensional optical diffraction tomography (ODT) to measure the Xenopus spindle's mass density distribution. While the spindle has been commonly referred to as a denser phase of the cytoplasm, we find that it has the same density as its surrounding, which makes it neutrally buoyant. Molecular perturbations suggest that spindle mass density can be modulated by tuning microtubule nucleation and dynamics. Together, ODT provides direct, unbiased, and quantitative information of the spindle's emergent physical properties-essential to advance predictive frameworks of spindle assembly and function.
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Affiliation(s)
- Abin Biswas
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Max-Planck-Institute for the Science of Light, 91058 Erlangen, Germany
| | - Kyoohyun Kim
- Max-Planck-Institute for the Science of Light, 91058 Erlangen, Germany; BIOTEC, Technische Universität Dresden, 01307 Dresden, Germany
| | - Gheorghe Cojoc
- BIOTEC, Technische Universität Dresden, 01307 Dresden, Germany
| | - Jochen Guck
- Max-Planck-Institute for the Science of Light, 91058 Erlangen, Germany; BIOTEC, Technische Universität Dresden, 01307 Dresden, Germany; Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
| | - Simone Reber
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; University of Applied Sciences Berlin, 13353 Berlin, Germany.
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30
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Goldstein-Levitin A, Pandey H, Allhuzaeel K, Kass I, Gheber L. Intracellular functions and motile properties of bi-directional kinesin-5 Cin8 are regulated by neck linker docking. eLife 2021; 10:71036. [PMID: 34387192 PMCID: PMC8456603 DOI: 10.7554/elife.71036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/13/2021] [Indexed: 12/03/2022] Open
Abstract
In this study, we analyzed intracellular functions and motile properties of neck-linker (NL) variants of the bi-directional S. cerevisiae kinesin-5 motor, Cin8. We also examined – by modeling – the configuration of H-bonds during NL docking. Decreasing the number of stabilizing H-bonds resulted in partially functional variants, as long as a conserved backbone H-bond at the N-latch position (proposed to stabilize the docked conformation of the NL) remained intact. Elimination of this conserved H-bond resulted in production of a non-functional Cin8 variant. Surprisingly, additional H-bond stabilization of the N-latch position, generated by replacement of the NL of Cin8 by sequences of the plus-end directed kinesin-5 Eg5, also produced a nonfunctional variant. In that variant, a single replacement of N-latch asparagine with glycine, as present in Cin8, eliminated the additional H-bond stabilization and rescued the functional defects. We conclude that exact N-latch stabilization during NL docking is critical for the function of bi-directional kinesin-5 Cin8.
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Affiliation(s)
| | - Himanshu Pandey
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Kanary Allhuzaeel
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Itamar Kass
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,InterX LTD, Ramat-Gan, Israel
| | - Larisa Gheber
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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31
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Effect of Kinesin-5 Tail Domain on Motor Dynamics for Antiparallel Microtubule Sliding. Int J Mol Sci 2021; 22:ijms22157857. [PMID: 34360622 PMCID: PMC8345995 DOI: 10.3390/ijms22157857] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 12/03/2022] Open
Abstract
Kinesin-5 motor consists of two pairs of heads and tail domains, which are situated at the opposite ends of a common stalk. The two pairs of heads can bind to two antiparallel microtubules (MTs) and move on the two MTs independently towards the plus ends, sliding apart the two MTs, which is responsible for chromosome segregation during mitosis. Prior experimental data showed that the tails of kinesin-5 Eg5 can modulate the dynamics of single motors and are critical for multiple motors to generate high steady forces to slide apart two antiparallel MTs. To understand the molecular mechanism of the tails modulating the ability of Eg5 motors, based on our proposed model the dynamics of the single Eg5 with the tails and that without the tails moving on single MTs is studied analytically and compared. Furthermore, the dynamics of antiparallel MT sliding by multiple Eg5 motors with the tails and that without the tails is studied numerically and compared. Both the analytical results for single motors and the numerical results for multiple motors are consistent with the available experimental data.
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32
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Skejo J, Garg SG, Gould SB, Hendriksen M, Tria FDK, Bremer N, Franjević D, Blackstone NW, Martin WF. Evidence for a Syncytial Origin of Eukaryotes from Ancestral State Reconstruction. Genome Biol Evol 2021; 13:evab096. [PMID: 33963405 PMCID: PMC8290118 DOI: 10.1093/gbe/evab096] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2021] [Indexed: 12/11/2022] Open
Abstract
Modern accounts of eukaryogenesis entail an endosymbiotic encounter between an archaeal host and a proteobacterial endosymbiont, with subsequent evolution giving rise to a unicell possessing a single nucleus and mitochondria. The mononucleate state of the last eukaryotic common ancestor (LECA) is seldom, if ever, questioned, even though cells harboring multiple (syncytia, coenocytes, and polykaryons) are surprisingly common across eukaryotic supergroups. Here, we present a survey of multinucleated forms. Ancestral character state reconstruction for representatives of 106 eukaryotic taxa using 16 different possible roots and supergroup sister relationships, indicate that LECA, in addition to being mitochondriate, sexual, and meiotic, was multinucleate. LECA exhibited closed mitosis, which is the rule for modern syncytial forms, shedding light on the mechanics of its chromosome segregation. A simple mathematical model shows that within LECA's multinucleate cytosol, relationships among mitochondria and nuclei were neither one-to-one, nor one-to-many, but many-to-many, placing mitonuclear interactions and cytonuclear compatibility at the evolutionary base of eukaryotic cell origin. Within a syncytium, individual nuclei and individual mitochondria function as the initial lower-level evolutionary units of selection, as opposed to individual cells, during eukaryogenesis. Nuclei within a syncytium rescue each other's lethal mutations, thereby postponing selection for viable nuclei and cytonuclear compatibility to the generation of spores, buffering transitional bottlenecks at eukaryogenesis. The prokaryote-to-eukaryote transition is traditionally thought to have left no intermediates, yet if eukaryogenesis proceeded via a syncytial common ancestor, intermediate forms have persisted to the present throughout the eukaryotic tree as syncytia but have so far gone unrecognized.
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Affiliation(s)
- Josip Skejo
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
- Faculty of Science, Division of Zoology, Department of Biology, University of Zagreb, Evolution Lab, Zagreb, Croatia
| | - Sriram G Garg
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Michael Hendriksen
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Fernando D K Tria
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Nico Bremer
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Damjan Franjević
- Faculty of Science, Division of Zoology, Department of Biology, University of Zagreb, Evolution Lab, Zagreb, Croatia
| | - Neil W Blackstone
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL, USA
| | - William F Martin
- Institute for Molecular Evolution, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
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33
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Mercadante DL, Manning AL, Olson SD. Modeling reveals cortical dynein-dependent fluctuations in bipolar spindle length. Biophys J 2021; 120:3192-3210. [PMID: 34197801 DOI: 10.1016/j.bpj.2021.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 10/21/2022] Open
Abstract
Proper formation and maintenance of the mitotic spindle is required for faithful cell division. Although much work has been done to understand the roles of the key molecular components of the mitotic spindle, identifying the consequences of force perturbations in the spindle remains a challenge. We develop a computational framework accounting for the minimal force requirements of mitotic progression. To reflect early spindle formation, we model microtubule dynamics and interactions with major force-generating motors, excluding chromosome interactions that dominate later in mitosis. We directly integrate our experimental data to define and validate the model. We then use simulations to analyze individual force components over time and their relationship to spindle dynamics, making it distinct from previously published models. We show through both model predictions and biological manipulation that rather than achieving and maintaining a constant bipolar spindle length, fluctuations in pole-to-pole distance occur that coincide with microtubule binding and force generation by cortical dynein. Our model further predicts that high dynein activity is required for spindle bipolarity when kinesin-14 (HSET) activity is also high. To the best of our knowledge, our results provide novel insight into the role of cortical dynein in the regulation of spindle bipolarity.
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Affiliation(s)
- Dayna L Mercadante
- Bioinformatics and Computational Biology Program, Worcester, Massachusetts
| | - Amity L Manning
- Department of Biology and Biotechnology, Worcester, Massachusetts.
| | - Sarah D Olson
- Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, Massachusetts.
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34
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Pandey H, Popov M, Goldstein-Levitin A, Gheber L. Mechanisms by Which Kinesin-5 Motors Perform Their Multiple Intracellular Functions. Int J Mol Sci 2021; 22:6420. [PMID: 34203964 PMCID: PMC8232732 DOI: 10.3390/ijms22126420] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/07/2021] [Indexed: 11/16/2022] Open
Abstract
Bipolar kinesin-5 motor proteins perform multiple intracellular functions, mainly during mitotic cell division. Their specialized structural characteristics enable these motors to perform their essential functions by crosslinking and sliding apart antiparallel microtubules (MTs). In this review, we discuss the specialized structural features of kinesin-5 motors, and the mechanisms by which these features relate to kinesin-5 functions and motile properties. In addition, we discuss the multiple roles of the kinesin-5 motors in dividing as well as in non-dividing cells, and examine their roles in pathogenetic conditions. We describe the recently discovered bidirectional motility in fungi kinesin-5 motors, and discuss its possible physiological relevance. Finally, we also focus on the multiple mechanisms of regulation of these unique motor proteins.
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Affiliation(s)
| | | | | | - Larisa Gheber
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel; (H.P.); (M.P.); (A.G.-L.)
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35
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Mani N, Wijeratne SS, Subramanian R. Micron-scale geometrical features of microtubules as regulators of microtubule organization. eLife 2021; 10:e63880. [PMID: 34114950 PMCID: PMC8195601 DOI: 10.7554/elife.63880] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/02/2021] [Indexed: 12/20/2022] Open
Abstract
The organization of micron-sized, multi-microtubule arrays from individual microtubules is essential for diverse cellular functions. The microtubule polymer is largely viewed as a passive building block during the organization process. An exception is the 'tubulin code' where alterations to tubulin at the amino acid level can influence the activity of microtubule-associated proteins. Recent studies reveal that micron-scale geometrical features of individual microtubules and polymer networks, such as microtubule length, overlap length, contact angle, and lattice defects, can also regulate the activity of microtubule-associated proteins and modulate polymer dynamics. We discuss how the interplay between such geometrical properties of the microtubule lattice and the activity of associated proteins direct multiple aspects of array organization, from microtubule nucleation and coalignment to specification of array dimensions and remodeling of dynamic networks. The mechanisms reviewed here highlight micron-sized features of microtubules as critical parameters to be routinely investigated in the study of microtubule self-organization.
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Affiliation(s)
- Nandini Mani
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Sithara S Wijeratne
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
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36
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Al Azzam O, Trussell CL, Reinemann DN. Measuring force generation within reconstituted microtubule bundle assemblies using optical tweezers. Cytoskeleton (Hoboken) 2021; 78:111-125. [PMID: 34051127 DOI: 10.1002/cm.21678] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 11/07/2022]
Abstract
Kinesins and microtubule associated proteins (MAPs) are critical to sustain life, facilitating cargo transport, cell division, and motility. To interrogate the mechanistic underpinnings of their function, these microtubule-based motors and proteins have been studied extensively at the single molecule level. However, a long-standing issue in the single molecule biophysics field has been how to investigate motors and associated proteins within a physiologically relevant environment in vitro. While the one motor/one filament orientation of a traditional optical trapping assay has revolutionized our knowledge of motor protein mechanics, this reductionist geometry does not reflect the structural hierarchy in which many motors work within the cellular environment. Here, we review approaches that combine the precision of optical tweezers with reconstituted ensemble systems of microtubules, MAPs, and kinesins to understand how each of these unique elements work together to perform large scale cellular tasks, such as but not limited to building the mitotic spindle. Not only did these studies develop novel techniques for investigating motor proteins in vitro, but they also illuminate ensemble filament and motor synergy that helps bridge the mechanistic knowledge gap between previous single molecule and cell level studies.
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Affiliation(s)
- Omayma Al Azzam
- Department of Chemical Engineering, University of Mississippi, University, Mississippi, USA
| | - Cameron Lee Trussell
- Department of Chemical Engineering, University of Mississippi, University, Mississippi, USA
| | - Dana N Reinemann
- Department of Chemical Engineering, University of Mississippi, University, Mississippi, USA.,Department of Biomedical Engineering, University of Mississippi, University, Mississippi, USA
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37
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Krüger LK, Gélin M, Ji L, Kikuti C, Houdusse A, Théry M, Blanchoin L, Tran PT. Kinesin-6 Klp9 orchestrates spindle elongation by regulating microtubule sliding and growth. eLife 2021; 10:67489. [PMID: 34080538 PMCID: PMC8205488 DOI: 10.7554/elife.67489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/02/2021] [Indexed: 11/13/2022] Open
Abstract
Mitotic spindle function depends on the precise regulation of microtubule dynamics and microtubule sliding. Throughout mitosis, both processes have to be orchestrated to establish and maintain spindle stability. We show that during anaphase B spindle elongation in Schizosaccharomyces pombe, the sliding motor Klp9 (kinesin-6) also promotes microtubule growth in vivo. In vitro, Klp9 can enhance and dampen microtubule growth, depending on the tubulin concentration. This indicates that the motor is able to promote and block tubulin subunit incorporation into the microtubule lattice in order to set a well-defined microtubule growth velocity. Moreover, Klp9 recruitment to spindle microtubules is dependent on its dephosphorylation mediated by XMAP215/Dis1, a microtubule polymerase, creating a link between the regulation of spindle length and spindle elongation velocity. Collectively, we unravel the mechanism of anaphase B, from Klp9 recruitment to the motors dual-function in regulating microtubule sliding and microtubule growth, allowing an inherent coordination of both processes.
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Affiliation(s)
- Lara Katharina Krüger
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Matthieu Gélin
- Institut de Recherche Saint Louis,U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France
| | - Liang Ji
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Carlos Kikuti
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Anne Houdusse
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Manuel Théry
- Institut de Recherche Saint Louis,U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France.,Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, Paris, France
| | - Laurent Blanchoin
- Institut de Recherche Saint Louis,U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France.,Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, Paris, France
| | - Phong T Tran
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France.,Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, United States
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38
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Chemical tools for dissecting cell division. Nat Chem Biol 2021; 17:632-640. [PMID: 34035515 PMCID: PMC10157795 DOI: 10.1038/s41589-021-00798-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 04/13/2021] [Indexed: 02/03/2023]
Abstract
Components of the cell division machinery typically function at varying cell cycle stages and intracellular locations. To dissect cellular mechanisms during the rapid division process, small-molecule probes act as complementary approaches to genetic manipulations, with advantages of temporal and in some cases spatial control and applicability to multiple model systems. This Review focuses on recent advances in chemical probes and applications to address select questions in cell division. We discuss uses of both enzyme inhibitors and chemical inducers of dimerization, as well as emerging techniques to promote future investigations. Overall, these concepts may open new research directions for applying chemical probes to advance cell biology.
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39
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Barisic M, Rajendraprasad G, Steblyanko Y. The metaphase spindle at steady state - Mechanism and functions of microtubule poleward flux. Semin Cell Dev Biol 2021; 117:99-117. [PMID: 34053864 DOI: 10.1016/j.semcdb.2021.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 11/24/2022]
Abstract
The mitotic spindle is a bipolar cellular structure, built from tubulin polymers, called microtubules, and interacting proteins. This macromolecular machine orchestrates chromosome segregation, thereby ensuring accurate distribution of genetic material into the two daughter cells during cell division. Powered by GTP hydrolysis upon tubulin polymerization, the microtubule ends exhibit a metastable behavior known as the dynamic instability, during which they stochastically switch between the growth and shrinkage phases. In the context of the mitotic spindle, dynamic instability is furthermore regulated by microtubule-associated proteins and motor proteins, which enables the spindle to undergo profound changes during mitosis. This highly dynamic behavior is essential for chromosome capture and congression in prometaphase, as well as for chromosome alignment to the spindle equator in metaphase and their segregation in anaphase. In this review we focus on the mechanisms underlying microtubule dynamics and sliding and their importance for the maintenance of shape, structure and dynamics of the metaphase spindle. We discuss how these spindle properties are related to the phenomenon of microtubule poleward flux, highlighting its highly cooperative molecular basis and role in keeping the metaphase spindle at a steady state.
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Affiliation(s)
- Marin Barisic
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark; Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| | - Girish Rajendraprasad
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Yulia Steblyanko
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark
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40
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Chen GY, Renda F, Zhang H, Gokden A, Wu DZ, Chenoweth DM, Khodjakov A, Lampson MA. Tension promotes kinetochore-microtubule release by Aurora B kinase. J Cell Biol 2021; 220:212027. [PMID: 33904910 PMCID: PMC8082439 DOI: 10.1083/jcb.202007030] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 02/06/2021] [Accepted: 03/24/2021] [Indexed: 12/19/2022] Open
Abstract
To ensure accurate chromosome segregation, interactions between kinetochores and microtubules are regulated by a combination of mechanics and biochemistry. Tension provides a signal to discriminate attachment errors from bi-oriented kinetochores with sisters correctly attached to opposite spindle poles. Biochemically, Aurora B kinase phosphorylates kinetochores to destabilize interactions with microtubules. To link mechanics and biochemistry, current models regard tension as an input signal to locally regulate Aurora B activity. Here, we show that the outcome of kinetochore phosphorylation depends on tension. Using optogenetics to manipulate Aurora B at individual kinetochores, we find that kinase activity promotes microtubule release when tension is high. Conversely, when tension is low, Aurora B activity promotes depolymerization of kinetochore–microtubules while maintaining attachment. Thus, phosphorylation converts a catch-bond, in which tension stabilizes attachments, to a slip-bond, which releases microtubules under tension. We propose that tension is a signal inducing distinct error-correction pathways, with release or depolymerization being advantageous for typical errors characterized by high or low tension, respectively.
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Affiliation(s)
- Geng-Yuan Chen
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
| | - Fioranna Renda
- Wadsworth Center, New York State Department of Health, Albany, NY
| | - Huaiying Zhang
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
| | - Alper Gokden
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
| | - Daniel Z Wu
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
| | - David M Chenoweth
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
| | - Alexey Khodjakov
- Wadsworth Center, New York State Department of Health, Albany, NY
| | - Michael A Lampson
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
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41
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Alfieri A, Gaska I, Forth S. Two modes of PRC1-mediated mechanical resistance to kinesin-driven microtubule network disruption. Curr Biol 2021; 31:2495-2506.e4. [PMID: 33848456 DOI: 10.1016/j.cub.2021.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 02/03/2021] [Accepted: 03/10/2021] [Indexed: 10/21/2022]
Abstract
The proper organization of the microtubule-based spindle during cell division requires the collective activity of many different proteins. These include non-motor microtubule-associated proteins (MAPs), whose functions include crosslinking microtubules to regulate filament sliding rates and assemble 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 remains unclear. 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.
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Affiliation(s)
- Angus Alfieri
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Ignas Gaska
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Scott Forth
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
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42
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Lamson AR, Moore JM, Fang F, Glaser MA, Shelley MJ, Betterton MD. Comparison of explicit and mean-field models of cytoskeletal filaments with crosslinking motors. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:45. [PMID: 33779863 PMCID: PMC8220871 DOI: 10.1140/epje/s10189-021-00042-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 02/20/2021] [Indexed: 05/17/2023]
Abstract
In cells, cytoskeletal filament networks are responsible for cell movement, growth, and division. Filaments in the cytoskeleton are driven and organized by crosslinking molecular motors. In reconstituted cytoskeletal systems, motor activity is responsible for far-from-equilibrium phenomena such as active stress, self-organized flow, and spontaneous nematic defect generation. How microscopic interactions between motors and filaments lead to larger-scale dynamics remains incompletely understood. To build from motor-filament interactions to predict bulk behavior of cytoskeletal systems, more computationally efficient techniques for modeling motor-filament interactions are needed. Here, we derive a coarse-graining hierarchy of explicit and continuum models for crosslinking motors that bind to and walk on filament pairs. We compare the steady-state motor distribution and motor-induced filament motion for the different models and analyze their computational cost. All three models agree well in the limit of fast motor binding kinetics. Evolving a truncated moment expansion of motor density speeds the computation by [Formula: see text]-[Formula: see text] compared to the explicit or continuous-density simulations, suggesting an approach for more efficient simulation of large networks. These tools facilitate further study of motor-filament networks on micrometer to millimeter length scales.
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Affiliation(s)
- Adam R Lamson
- Department of Physics, University of Colorado Boulder, Boulder, USA.
| | - Jeffrey M Moore
- Department of Physics, University of Colorado Boulder, Boulder, USA
| | - Fang Fang
- Courant Institute, New York University, New York, USA
| | - Matthew A Glaser
- Department of Physics, University of Colorado Boulder, Boulder, USA
| | - Michael J Shelley
- Courant Institute, New York University, New York, USA
- Center for Computational Biology, Flatiron Institute, New York, USA
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43
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Shinde A, Illath K, Gupta P, Shinde P, Lim KT, Nagai M, Santra TS. A Review of Single-Cell Adhesion Force Kinetics and Applications. Cells 2021; 10:577. [PMID: 33808043 PMCID: PMC8000588 DOI: 10.3390/cells10030577] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023] Open
Abstract
Cells exert, sense, and respond to the different physical forces through diverse mechanisms and translating them into biochemical signals. The adhesion of cells is crucial in various developmental functions, such as to maintain tissue morphogenesis and homeostasis and activate critical signaling pathways regulating survival, migration, gene expression, and differentiation. More importantly, any mutations of adhesion receptors can lead to developmental disorders and diseases. Thus, it is essential to understand the regulation of cell adhesion during development and its contribution to various conditions with the help of quantitative methods. The techniques involved in offering different functionalities such as surface imaging to detect forces present at the cell-matrix and deliver quantitative parameters will help characterize the changes for various diseases. Here, we have briefly reviewed single-cell mechanical properties for mechanotransduction studies using standard and recently developed techniques. This is used to functionalize from the measurement of cellular deformability to the quantification of the interaction forces generated by a cell and exerted on its surroundings at single-cell with attachment and detachment events. The adhesive force measurement for single-cell microorganisms and single-molecules is emphasized as well. This focused review should be useful in laying out experiments which would bring the method to a broader range of research in the future.
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Affiliation(s)
- Ashwini Shinde
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Kavitha Illath
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Pallavi Gupta
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Pallavi Shinde
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Ki-Taek Lim
- Department of Biosystems Engineering, Kangwon National University, Chuncheon-Si, Gangwon-Do 24341, Korea;
| | - Moeto Nagai
- Department of Mechanical Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan;
| | - Tuhin Subhra Santra
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
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44
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Budaitis BG, Jariwala S, Rao L, Yue Y, Sept D, Verhey KJ, Gennerich A. Pathogenic mutations in the kinesin-3 motor KIF1A diminish force generation and movement through allosteric mechanisms. J Cell Biol 2021; 220:211720. [PMID: 33496723 PMCID: PMC7844421 DOI: 10.1083/jcb.202004227] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 10/27/2020] [Accepted: 12/30/2020] [Indexed: 02/07/2023] Open
Abstract
The kinesin-3 motor KIF1A functions in neurons, where its fast and superprocessive motility facilitates long-distance transport, but little is known about its force-generating properties. Using optical tweezers, we demonstrate that KIF1A stalls at an opposing load of ~3 pN but more frequently detaches at lower forces. KIF1A rapidly reattaches to the microtubule to resume motion due to its class-specific K-loop, resulting in a unique clustering of force generation events. To test the importance of neck linker docking in KIF1A force generation, we introduced mutations linked to human neurodevelopmental disorders. Molecular dynamics simulations predict that V8M and Y89D mutations impair neck linker docking. Indeed, both mutations dramatically reduce the force generation of KIF1A but not the motor’s ability to rapidly reattach to the microtubule. Although both mutations relieve autoinhibition of the full-length motor, the mutant motors display decreased velocities, run lengths, and landing rates and delayed cargo transport in cells. These results advance our understanding of how mutations in KIF1A can manifest in disease.
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Affiliation(s)
- Breane G Budaitis
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI
| | - Shashank Jariwala
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI
| | - Lu Rao
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY
| | - Yang Yue
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - David Sept
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI
| | - Kristen J Verhey
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Arne Gennerich
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY
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45
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Xie P. A common ATP-dependent stepping model for kinesin-5 and kinesin-1: Mechanism of bi-directionality of kinesin-5. Biophys Chem 2021; 271:106548. [PMID: 33486269 DOI: 10.1016/j.bpc.2021.106548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/03/2021] [Accepted: 01/12/2021] [Indexed: 01/21/2023]
Abstract
Kinesin-5 and kinesin-1 proteins are two families of kinesin superfamily molecular motors that can move processively on microtubules powered by ATP hydrolysis. Kinesin-1 is a unidirectional motor. By contrast, some yeast kinesin-5 motors are bidirectional and the directionality can be switched by changing the experimental conditions. Here, on the basis of a common chemomechanical coupling model, the dynamics of kinesin-1 and in particular the dynamics of kinesin-5 is studied theoretically, explaining the available experimental data. For example, the experimental data about different movement directions under different experimental conditions for kinesin-5 are explained well. The origin of why kinesin-1 can only make unidirectional movement and kinesin-5 can make bidirectional movements is revealed. The origin of mutations or deletions of several structural elements affecting the directionality of kinesin-5 is revealed. Moreover, some predicted results for kinesin-5 are provided.
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Affiliation(s)
- Ping Xie
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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46
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Zaniewski TM, Gicking AM, Fricks J, Hancock WO. A kinetic dissection of the fast and superprocessive kinesin-3 KIF1A reveals a predominant one-head-bound state during its chemomechanical cycle. J Biol Chem 2020; 295:17889-17903. [PMID: 33082143 PMCID: PMC7939386 DOI: 10.1074/jbc.ra120.014961] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/14/2020] [Indexed: 12/15/2022] Open
Abstract
The kinesin-3 family contains the fastest and most processive motors of the three neuronal transport kinesin families, yet the sequence of states and rates of kinetic transitions that comprise the chemomechanical cycle and give rise to their unique properties are poorly understood. We used stopped-flow fluorescence spectroscopy and single-molecule motility assays to delineate the chemomechanical cycle of the kinesin-3, KIF1A. Our bacterially expressed KIF1A construct, dimerized via a kinesin-1 coiled-coil, exhibits fast velocity and superprocessivity behavior similar to WT KIF1A. We established that the KIF1A forward step is triggered by hydrolysis of ATP and not by ATP binding, meaning that KIF1A follows the same chemomechanical cycle as established for kinesin-1 and -2. The ATP-triggered half-site release rate of KIF1A was similar to the stepping rate, indicating that during stepping, rear-head detachment is an order of magnitude faster than in kinesin-1 and kinesin-2. Thus, KIF1A spends the majority of its hydrolysis cycle in a one-head-bound state. Both the ADP off-rate and the ATP on-rate at physiological ATP concentration were fast, eliminating these steps as possible rate-limiting transitions. Based on the measured run length and the relatively slow off-rate in ADP, we conclude that attachment of the tethered head is the rate-limiting transition in the KIF1A stepping cycle. Thus, KIF1A's activity can be explained by a fast rear-head detachment rate, a rate-limiting step of tethered-head attachment that follows ATP hydrolysis, and a relatively strong electrostatic interaction with the microtubule in the weakly bound post-hydrolysis state.
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Affiliation(s)
- Taylor M Zaniewski
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Allison M Gicking
- Department of Biomedical Engineering and Bioengineering Graduate Program, Pennsylvania State University, University Park, Pennsylvania, USA
| | - John Fricks
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona, USA
| | - William O Hancock
- Department of Biomedical Engineering and Bioengineering Graduate Program, Pennsylvania State University, University Park, Pennsylvania, USA.
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47
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Ong JY, Bradley MC, Torres JZ. Phospho-regulation of mitotic spindle assembly. Cytoskeleton (Hoboken) 2020; 77:558-578. [PMID: 33280275 PMCID: PMC7898546 DOI: 10.1002/cm.21649] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/08/2020] [Accepted: 12/02/2020] [Indexed: 12/23/2022]
Abstract
The assembly of the bipolar mitotic spindle requires the careful orchestration of a myriad of enzyme activities like protein posttranslational modifications. Among these, phosphorylation has arisen as the principle mode for spatially and temporally activating the proteins involved in early mitotic spindle assembly processes. Here, we review key kinases, phosphatases, and phosphorylation events that regulate critical aspects of these processes. We highlight key phosphorylation substrates that are important for ensuring the fidelity of centriole duplication, centrosome maturation, and the establishment of the bipolar spindle. We also highlight techniques used to understand kinase-substrate relationships and to study phosphorylation events. We conclude with perspectives on the field of posttranslational modifications in early mitotic spindle assembly.
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Affiliation(s)
- Joseph Y Ong
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA
| | - Michelle C Bradley
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA
| | - Jorge Z Torres
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA.,Molecular Biology Institute, University of California, Los Angeles, California, USA.,Jonsson Comprehensive Cancer Center, University of California, Los Angeles, California, USA
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48
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Pavin N, Tolić IM. Mechanobiology of the Mitotic Spindle. Dev Cell 2020; 56:192-201. [PMID: 33238148 DOI: 10.1016/j.devcel.2020.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/06/2020] [Accepted: 11/02/2020] [Indexed: 10/22/2022]
Abstract
The mitotic spindle is a microtubule-based assembly that separates the chromosomes during cell division. As the spindle is basically a mechanical micro machine, the understanding of its functioning is constantly motivating the development of experimental approaches based on mechanical perturbations, which are complementary to and work together with the classical genetics and biochemistry methods. Recent data emerging from these approaches in combination with theoretical modeling led to novel ideas and significant revisions of the basic concepts in the field. In this Perspective, we discuss the advances in the understanding of spindle mechanics, focusing on microtubule forces that control chromosome movements.
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Affiliation(s)
- Nenad Pavin
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia.
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
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49
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Fang CT, Kuo HH, Hsu SC, Yih LH. HSP70 regulates Eg5 distribution within the mitotic spindle and modulates the cytotoxicity of Eg5 inhibitors. Cell Death Dis 2020; 11:715. [PMID: 32873777 PMCID: PMC7462862 DOI: 10.1038/s41419-020-02919-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 02/06/2023]
Abstract
The heat shock protein 70 (HSP70) is a conserved molecular chaperone and proteostasis regulator that protects cells from pharmacological stress and promotes drug resistance in cancer cells. In this study, we found that HSP70 may promote resistance to anticancer drugs that target the mitotic kinesin, Eg5, which is essential for assembly and maintenance of the mitotic spindle and cell proliferation. Our data show that loss of HSP70 activity enhances Eg5 inhibitor-induced cytotoxicity and spindle abnormalities. Furthermore, HSP70 colocalizes with Eg5 in the mitotic spindle, and inhibition of HSP70 disrupts this colocalization. Inhibition or depletion of HSP70 also causes Eg5 to accumulate at the spindle pole, altering microtubule dynamics and leading to chromosome misalignment. Using ground state depletion microscopy followed by individual molecule return (GSDIM), we found that HSP70 inhibition reduces the size of Eg5 ensembles and prevents their localization to the inter-polar region of the spindle. In addition, bis(maleimido)hexane-mediated protein-protein crosslinking and proximity ligation assays revealed that HSP70 inhibition deregulates the interaction between Eg5 tetramers and TPX2 at the spindle pole, leading to their accumulation in high-molecular-weight complexes. Finally, we showed that the passive substrate-binding activity of HSP70 is required for appropriate Eg5 distribution and function. Together, our results show that HSP70 substrate-binding activity may regulate proper assembly of Eg5 ensembles and Eg5-TPX2 complexes to modulate mitotic distribution/function of Eg5. Thus, HSP70 inhibition may sensitize cancer cells to Eg5 inhibitor-induced cytotoxicity.
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Affiliation(s)
- Chieh-Ting Fang
- Department of Life Science, National Taiwan University, Taipei, Taiwan.,Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Hsiao-Hui Kuo
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Shao-Chun Hsu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Ling-Huei Yih
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
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50
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Wierenga H, Wolde PRT. Diffusible Cross-linkers Cause Superexponential Friction Forces. PHYSICAL REVIEW LETTERS 2020; 125:078101. [PMID: 32857554 DOI: 10.1103/physrevlett.125.078101] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 07/15/2020] [Indexed: 06/11/2023]
Abstract
The friction between cytoskeletal filaments is of central importance for the formation of cellular structures such as the mitotic spindle and the cytokinetic ring. This friction is caused by passive cross-linkers, yet the underlying mechanism and the dependence on cross-linker density are poorly understood. Here, we use theory and computer simulations to study the friction between two filaments that are cross-linked by passive proteins, which can hop between discrete binding sites while physically excluding each other. The simulations reveal that filaments move via rare discrete jumps, which are associated with free-energy barrier crossings. We identify the reaction coordinate that governs the relative microtubule movement and derive an exact analytical expression for the free-energy barrier and the friction coefficient. Our analysis not only elucidates the molecular mechanism underlying cross-linker-induced filament friction, but also predicts that the friction coefficient scales superexponentially with the density of cross-linkers.
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