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Antonijevic M, Sopkova-de Oliveira Santos J, Dallemagne P, Rochais C. Discovery of a pocket network on the domain 5 of the TrkB receptor - A potential new target in the quest for the new ligands. Mol Inform 2024:e202400043. [PMID: 38619318 DOI: 10.1002/minf.202400043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/06/2024] [Accepted: 03/26/2024] [Indexed: 04/16/2024]
Abstract
The important role that the neurotrophin tyrosine kinase receptor - TrkB has in the pathogenesis of several neurodegenerative conditions such are Alzheimer's disease, Parkinson's disease, Huntington's disease, has been well described. This shouldn't be a surprise, since in the physiological conditions, once activated by brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5), the TrkB receptor promotes neuronal survival, differentiation and synaptic function. Considering that the natural ligands for TrkB receptor are large proteins, it is a challenge to discover small molecule capable to mimic their effects. Even though, the surface of receptor that is interacting with BDNF or NT-4/5 is known, there was always a question which pocket and interaction is responsible for activation of it. In order to answer this challenging question, we have used molecular dynamic (MD) simulations and Pocketron algorithm which enabled us to detect, for the first time, a pocket network existing in the interacting domain (d5) of the receptor; to describe them and to see how they are communicating with each other. This new discovery gave us potential new areas on receptor that can be targeted and used for structure-based drug design approach in the development of the new ligands.
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Sankaranarayanan SR, Polisetty SD, Das K, Dumbrepatil A, Medina-Pritchard B, Singleton M, Jeyaprakash AA, Sanyal K. Functional plasticity in chromosome-microtubule coupling on the evolutionary time scale. Life Sci Alliance 2023; 6:e202201720. [PMID: 37793775 PMCID: PMC10551642 DOI: 10.26508/lsa.202201720] [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: 09/12/2022] [Revised: 09/15/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023] Open
Abstract
The Dam1 complex is essential for mitotic progression across evolutionarily divergent fungi. Upon analyzing amino acid (aa) sequences of Dad2, a Dam1 complex subunit, we identified a conserved 10-aa-long Dad2 signature sequence (DSS). An arginine residue (R126) in the DSS is essential for viability in Saccharomyces cerevisiae that possesses point centromeres. The corresponding arginine residues are functionally important but not essential for viability in Candida albicans and Cryptococcus neoformans; both carry several kilobases long regional centromeres. The purified recombinant Dam1 complex containing either Dad2ΔDSS or Dad2R126A failed to bind microtubules (MTs) or form any visible rings like the WT complex. Intriguingly, functional analysis revealed that the requirement of the conserved arginine residue for chromosome biorientation and mitotic progression reduced with increasing centromere length. We propose that plasticity of the invariant arginine of Dad2 in organisms with regional centromeres is achieved by conditional elevation of the kinetochore protein(s) to enable multiple kinetochore MTs to bind to each chromosome. The capacity of a chromosome to bind multiple kinetochore MTs may mask the deleterious effects of such lethal mutations.
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Affiliation(s)
- Sundar Ram Sankaranarayanan
- https://ror.org/0538gdx71 Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Satya Dev Polisetty
- https://ror.org/0538gdx71 Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Kuladeep Das
- https://ror.org/0538gdx71 Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Arti Dumbrepatil
- https://ror.org/0538gdx71 Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Bethan Medina-Pritchard
- https://ror.org/01nrxwf90 Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Martin Singleton
- https://ror.org/01nrxwf90 Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - A Arockia Jeyaprakash
- https://ror.org/01nrxwf90 Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
- Gene Center and Department of Biochemistry, Ludwig-Maximilian-Universität, Munich, Germany
| | - Kaustuv Sanyal
- https://ror.org/0538gdx71 Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
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3
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Villa-Consuegra S, Tallada VA, Jimenez J. Aurora B kinase erases monopolar microtubule-kinetochore arrays at the meiosis I-II transition. iScience 2023; 26:108339. [PMID: 38026180 PMCID: PMC10654595 DOI: 10.1016/j.isci.2023.108339] [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: 09/20/2023] [Revised: 10/09/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
During meiosis, faithful chromosome segregation requires monopolar spindle microtubule-kinetochore arrays in MI to segregate homologous chromosomes, but bipolar in MII to segregate sister chromatids. Using fission yeasts, we found that the universal Aurora B kinase localizes to kinetochores in metaphase I and in the mid-spindle during anaphase I, as in mitosis; but in the absence of an intervening S phase, the importin α Imp1 propitiates its release from the spindle midzone to re-localize at kinetochores during meiotic interkinesis. We show that "error-correction" activity of kinetochore re-localized Aurora B becomes essential to erase monopolar arrangements from anaphase I, a prerequisite to satisfy the spindle assembly checkpoint (SAC) and to generate proper bipolar arrays at the onset of MII. This microtubule-kinetochore resetting activity of Aurora B at the MI-MII transition is required to prevent chromosome missegregation in meiosis II, a type of error often associated with birth defects and infertility in humans.
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Affiliation(s)
- Sergio Villa-Consuegra
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Carretera de Utrera Km1, 41013 Seville, Spain
| | - Víctor A. Tallada
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Carretera de Utrera Km1, 41013 Seville, Spain
| | - Juan Jimenez
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Carretera de Utrera Km1, 41013 Seville, Spain
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4
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Zahm JA, Jenni S, Harrison SC. Structure of the Ndc80 complex and its interactions at the yeast kinetochore-microtubule interface. Open Biol 2023; 13:220378. [PMID: 36883282 PMCID: PMC9993044 DOI: 10.1098/rsob.220378] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
The conserved Ndc80 kinetochore complex, Ndc80c, is the principal link between mitotic spindle microtubules and centromere-associated proteins. We used AlphaFold 2 (AF2) to obtain predictions of the Ndc80 'loop' structure and of the Ndc80 : Nuf2 globular head domains that interact with the Dam1 subunit of the heterodecameric DASH/Dam1 complex (Dam1c). The predictions guided design of crystallizable constructs, with structures close to the predicted ones. The Ndc80 'loop' is a stiff, α-helical 'switchback' structure; AF2 predictions and positions of preferential cleavage sites indicate that flexibility within the long Ndc80c rod occurs instead at a hinge closer to the globular head. Conserved stretches of the Dam1 C terminus bind Ndc80c such that phosphorylation of Dam1 serine residues 257, 265 and 292 by the mitotic kinase Ipl1/Aurora B can release this contact during error correction of mis-attached kinetochores. We integrate the structural results presented here into our current molecular model of the kinetochore-microtubule interface. The model illustrates how multiple interactions between Ndc80c, DASH/Dam1c and the microtubule lattice stabilize kinetochore attachments.
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Affiliation(s)
- Jacob A. Zahm
- Department of Biological Chemistry and Molecular Pharmacology, and
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, and
| | - Stephen C. Harrison
- Department of Biological Chemistry and Molecular Pharmacology, and
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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5
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Murase Y, Yamagishi M, Okada N, Toya M, Yajima J, Hamada T, Sato M. Fission yeast Dis1 is an unconventional TOG/XMAP215 that induces microtubule catastrophe to drive chromosome pulling. Commun Biol 2022; 5:1298. [PMID: 36435910 PMCID: PMC9701203 DOI: 10.1038/s42003-022-04271-2] [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: 08/05/2022] [Accepted: 11/16/2022] [Indexed: 11/28/2022] Open
Abstract
The shortening of microtubules attached to kinetochores is the driving force of chromosome movement during cell division. Specific kinesins are believed to shorten microtubules but are dispensable for viability in yeast, implying the existence of additional factors responsible for microtubule shortening. Here, we demonstrate that Dis1, a TOG/XMAP215 ortholog in fission yeast, promotes microtubule shortening to carry chromosomes. Although TOG/XMAP215 orthologs are generally accepted as microtubule polymerases, Dis1 promoted microtubule catastrophe in vitro and in vivo. Notably, microtubule catastrophe was promoted when the tip was attached to kinetochores, as they steadily anchored Dis1 at the kinetochore-microtubule interface. Engineered Dis1 oligomers artificially tethered at a chromosome arm region induced the shortening of microtubules in contact, frequently pulling the chromosome arm towards spindle poles. This effect was not brought by oligomerised Alp14. Thus, unlike Alp14 and other TOG/XMAP215 orthologs, Dis1 plays an unconventional role in promoting microtubule catastrophe, thereby driving chromosome movement.
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Affiliation(s)
- Yuichi Murase
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan
| | - Masahiko Yamagishi
- grid.26999.3d0000 0001 2151 536XDepartment of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, 153-8902 Tokyo Japan
| | - Naoyuki Okada
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan ,grid.5808.50000 0001 1503 7226Instituto de Biologia Molecular e Celular, Instituto de Investigacao e Inovacao em Saude (i3S), Universidade do Porto, 208 Rua Alfredo Allen, 4200-135 Porto, Portugal
| | - Mika Toya
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan ,grid.5290.e0000 0004 1936 9975Global Center for Science and Engineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 Japan ,grid.5290.e0000 0004 1936 9975Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 Japan
| | - Junichiro Yajima
- grid.26999.3d0000 0001 2151 536XDepartment of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, 153-8902 Tokyo Japan ,grid.26999.3d0000 0001 2151 536XKomaba Institute for Science, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, 153-8902 Tokyo Japan ,grid.26999.3d0000 0001 2151 536XResearch Center for Complex Systems Biology, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, 153-8902 Tokyo Japan
| | - Takahiro Hamada
- grid.444568.f0000 0001 0672 2184Department of Bioscience, Faculty of Life Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama-shi 700-0005 Japan
| | - Masamitsu Sato
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan ,grid.5290.e0000 0004 1936 9975Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 Japan ,grid.5290.e0000 0004 1936 9975Institute for Medical-Oriented Structural Biology, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan
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6
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Kuenzel NA, Alcázar-Román AR, Saiardi A, Bartsch SM, Daunaraviciute S, Fiedler D, Fleig U. Inositol Pyrophosphate-Controlled Kinetochore Architecture and Mitotic Entry in S. pombe. J Fungi (Basel) 2022; 8:933. [PMID: 36135658 PMCID: PMC9506091 DOI: 10.3390/jof8090933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Inositol pyrophosphates (IPPs) comprise a specific class of signaling molecules that regulate central biological processes in eukaryotes. The conserved Vip1/PPIP5K family controls intracellular IP8 levels, the highest phosphorylated form of IPPs present in yeasts, as it has both inositol kinase and pyrophosphatase activities. Previous studies have shown that the fission yeast S. pombe Vip1/PPIP5K family member Asp1 impacts chromosome transmission fidelity via the modulation of spindle function. We now demonstrate that an IP8 analogue is targeted by endogenous Asp1 and that cellular IP8 is subject to cell cycle control. Mitotic entry requires Asp1 kinase function and IP8 levels are increased at the G2/M transition. In addition, the kinetochore, the conductor of chromosome segregation that is assembled on chromosomes is modulated by IP8. Members of the yeast CCAN kinetochore-subcomplex such as Mal2/CENP-O localize to the kinetochore depending on the intracellular IP8-level: higher than wild-type IP8 levels reduce Mal2 kinetochore targeting, while a reduction in IP8 has the opposite effect. As our perturbations of the inositol polyphosphate and IPP pathways demonstrate that kinetochore architecture depends solely on IP8 and not on other IPPs, we conclude that chromosome transmission fidelity is controlled by IP8 via an interplay between entry into mitosis, kinetochore architecture, and spindle dynamics.
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Affiliation(s)
- Natascha Andrea Kuenzel
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Abel R. Alcázar-Román
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower St., London WC1E 6BT, UK
| | - Simon M. Bartsch
- Leibniz Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Sarune Daunaraviciute
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Dorothea Fiedler
- Leibniz Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Ursula Fleig
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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7
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Jiménez-Martín A, Pineda-Santaella A, Pinto-Cruz J, León-Periñán D, García-Sánchez S, Delgado-Gestoso D, Marín-Toral L, Fernández-Álvarez A. The Rabl chromosome configuration masks a kinetochore reassembly mechanism in yeast mitosis. Mol Biol Cell 2022; 33:br8. [PMID: 35274979 PMCID: PMC9282007 DOI: 10.1091/mbc.e20-09-0600] [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] [Indexed: 11/21/2022] Open
Abstract
During cell cycle progression in metazoans, the kinetochore is assembled at mitotic onset and disassembled during mitotic exit. Once assembled, the kinetochore complex attached to centromeres interacts directly with the spindle microtubules, the vehicle of chromosome segregation. This reassembly program is assumed to be absent in budding and fission yeast, because most kinetochore proteins are stably maintained at the centromeres throughout the entire cell cycle. Here, we show that the reassembly program of the outer kinetochore at mitotic onset is unexpectedly conserved in the fission yeast Schizosaccharomyces pombe. We identified this behavior by removing the Rabl chromosome configuration, in which centromeres are permanently associated with the nuclear envelope beneath the spindle pole body during interphase. In addition to having evolutionary implications for kinetochore reassembly, our results aid the understanding of the molecular processes responsible for kinetochore disassembly and assembly during mitotic entry.
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Affiliation(s)
- Alberto Jiménez-Martín
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain).,Instituto de Biología Funcional y Genómica (IBFG) (Consejo Superior de Investigaciones Científicas and Universidad de Salamanca). Calle Zacarías González 2, 37007 Salamanca (Spain)
| | - Alberto Pineda-Santaella
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain)
| | - Jesús Pinto-Cruz
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain)
| | - Daniel León-Periñán
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain)
| | - Sabas García-Sánchez
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain)
| | - David Delgado-Gestoso
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain)
| | - Laura Marín-Toral
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain)
| | - Alfonso Fernández-Álvarez
- Andalusian Center for Developmental Biology (CABD) (Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía). Ctra. Utrera km. 1, 41013 Seville (Spain).,Instituto de Biología Funcional y Genómica (IBFG) (Consejo Superior de Investigaciones Científicas and Universidad de Salamanca). Calle Zacarías González 2, 37007 Salamanca (Spain)
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8
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Kursel LE, Cope HD, Rog O. Unconventional conservation reveals structure-function relationships in the synaptonemal complex. eLife 2021; 10:72061. [PMID: 34787570 PMCID: PMC8598163 DOI: 10.7554/elife.72061] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/21/2021] [Indexed: 12/29/2022] Open
Abstract
Functional requirements constrain protein evolution, commonly manifesting in a conserved amino acid sequence. Here, we extend this idea to secondary structural features by tracking their conservation in essential meiotic proteins with highly diverged sequences. The synaptonemal complex (SC) is a ~100-nm-wide ladder-like meiotic structure present in all eukaryotic clades, where it aligns parental chromosomes and regulates exchanges between them. Despite the conserved ultrastructure and functions of the SC, SC proteins are highly divergent within Caenorhabditis. However, SC proteins have highly conserved length and coiled-coil domain structure. We found the same unconventional conservation signature in Drosophila and mammals, and used it to identify a novel SC protein in Pristionchus pacificus, Ppa-SYP-1. Our work suggests that coiled-coils play wide-ranging roles in the structure and function of the SC, and more broadly, that expanding sequence analysis beyond measures of per-site similarity can enhance our understanding of protein evolution and function.
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Affiliation(s)
- Lisa E Kursel
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, Salt Lake City, United States
| | - Henry D Cope
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, Salt Lake City, United States
| | - Ofer Rog
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, Salt Lake City, United States
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9
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Li J, Wang Y, Zou W, Jian L, Fu Y, Zhao J. AtNUF2 modulates spindle microtubule organization and chromosome segregation during mitosis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:801-816. [PMID: 33993566 DOI: 10.1111/tpj.15347] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
The NDC80 complex is a conserved eukaryotic complex composed of four subunits (NUF2, SPC25, NDC80, and SPC24). In yeast and animal cells, the complex is located at the outer layer of the kinetochore, connecting the inner layer of the kinetochore and spindle microtubules (MTs) during cell division. In higher plants, the relationship of the NDC80 complex with MTs is still unclear. In this study, we characterized the biological function of AtNUF2, a subunit of the Arabidopsis NDC80 complex. We found that AtNUF2 is widely expressed in various organs, especially in different stages of embryonic development. It was verified that AtNUF2 co-localized with α-tubulin on MTs during mitosis by immunohistochemical assays. Mutation of AtNUF2 led to severe mitotic defects, not only in the embryo and endosperm, but also in seedlings, resulting in seed abortion and stagnating seedling growth. Furthermore, the biological function of AtNUF2 was studied using partially complemented nuf2-3/-DD45;ABI3pro::AtNUF2 (nuf2-3/-DA ) seedlings. The chromosome bridge and lagging chromatids occurred in nuf2-3/-DA root apical meristem cells, along with aberration of spindle MTs, resulting in blocked root growth. Meanwhile, the direct binding of AtNUF2 and AtSPC25 to MTs was determined by an MT co-sedimentation assay in vitro. This study revealed the function of AtNUF2 in mitosis and the underlying mechanisms, modulating spindle MT organization and ensuring chromosome segregation during embryo, endosperm, and root development, laying the foundation for subsequent research of the NDC80 complex.
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Affiliation(s)
- Jin Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yutao Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Wenxuan Zou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Liufang Jian
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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10
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Shake It Off: The Elimination of Erroneous Kinetochore-Microtubule Attachments and Chromosome Oscillation. Int J Mol Sci 2021; 22:ijms22063174. [PMID: 33804687 PMCID: PMC8003821 DOI: 10.3390/ijms22063174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/18/2021] [Indexed: 01/17/2023] Open
Abstract
Cell proliferation and sexual reproduction require the faithful segregation of chromosomes. Chromosome segregation is driven by the interaction of chromosomes with the spindle, and the attachment of chromosomes to the proper spindle poles is essential. Initial attachments are frequently erroneous due to the random nature of the attachment process; however, erroneous attachments are selectively eliminated. Proper attachment generates greater tension at the kinetochore than erroneous attachments, and it is thought that attachment selection is dependent on this tension. However, studies of meiotic chromosome segregation suggest that attachment elimination cannot be solely attributed to tension, and the precise mechanism of selective elimination of erroneous attachments remains unclear. During attachment elimination, chromosomes oscillate between the spindle poles. A recent study on meiotic chromosome segregation in fission yeast has suggested that attachment elimination is coupled to chromosome oscillation. In this review, the possible contribution of chromosome oscillation in the elimination of erroneous attachment is discussed in light of the recent finding.
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11
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Zahm JA, Stewart MG, Carrier JS, Harrison SC, Miller MP. Structural basis of Stu2 recruitment to yeast kinetochores. eLife 2021; 10:e65389. [PMID: 33591274 PMCID: PMC7909949 DOI: 10.7554/elife.65389] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/15/2021] [Indexed: 12/02/2022] Open
Abstract
Chromosome segregation during cell division requires engagement of kinetochores of sister chromatids with microtubules emanating from opposite poles. As the corresponding microtubules shorten, these 'bioriented' sister kinetochores experience tension-dependent stabilization of microtubule attachments. The yeast XMAP215 family member and microtubule polymerase, Stu2, associates with kinetochores and contributes to tension-dependent stabilization in vitro. We show here that a C-terminal segment of Stu2 binds the four-way junction of the Ndc80 complex (Ndc80c) and that residues conserved both in yeast Stu2 orthologs and in their metazoan counterparts make specific contacts with Ndc80 and Spc24. Mutations that perturb this interaction prevent association of Stu2 with kinetochores, impair cell viability, produce biorientation defects, and delay cell cycle progression. Ectopic tethering of the mutant Stu2 species to the Ndc80c junction restores wild-type function in vivo. These findings show that the role of Stu2 in tension-sensing depends on its association with kinetochores by binding with Ndc80c.
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Affiliation(s)
- Jacob A Zahm
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Howard Hughes Medical InstituteBostonUnited States
| | - Michael G Stewart
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Joseph S Carrier
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Howard Hughes Medical InstituteBostonUnited States
| | - Matthew P Miller
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
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12
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Wakiya M, Nishi E, Kawai S, Yamada K, Katsumata K, Hirayasu A, Itabashi Y, Yamamoto A. Chiasmata and the kinetochore component Dam1 are crucial for elimination of erroneous chromosome attachments and centromere oscillation at meiosis I. Open Biol 2021; 11:200308. [PMID: 33529549 PMCID: PMC8061696 DOI: 10.1098/rsob.200308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Establishment of proper chromosome attachments to the spindle requires elimination of erroneous attachments, but the mechanism of this process is not fully understood. During meiosis I, sister chromatids attach to the same spindle pole (mono-oriented attachment), whereas homologous chromosomes attach to opposite poles (bi-oriented attachment), resulting in homologous chromosome segregation. Here, we show that chiasmata that link homologous chromosomes and kinetochore component Dam1 are crucial for elimination of erroneous attachments and oscillation of centromeres between the spindle poles at meiosis I in fission yeast. In chiasma-forming cells, Mad2 and Aurora B kinase, which provides time for attachment correction and destabilizes erroneous attachments, respectively, caused elimination of bi-oriented attachments of sister chromatids, whereas in chiasma-lacking cells, they caused elimination of mono-oriented attachments. In chiasma-forming cells, in addition, homologous centromere oscillation was coordinated. Furthermore, Dam1 contributed to attachment elimination in both chiasma-forming and chiasma-lacking cells, and drove centromere oscillation. These results demonstrate that chiasmata alter attachment correction patterns by enabling error correction factors to eliminate bi-oriented attachment of sister chromatids, and suggest that Dam1 induces elimination of erroneous attachments. The coincidental contribution of chiasmata and Dam1 to centromere oscillation also suggests a potential link between centromere oscillation and attachment elimination.
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Affiliation(s)
- Misuzu Wakiya
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Eriko Nishi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Shinnosuke Kawai
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.,Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kohei Yamada
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kazuhiro Katsumata
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Ami Hirayasu
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yuta Itabashi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Ayumu Yamamoto
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.,Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
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13
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Zhu Y, Zhang Y, Liu N, Ren W, Hou Y, Duan Y, Song X, Zhou M. The Dis1/Stu2/XMAP215 Family Gene FgStu2 Is Involved in Vegetative Growth, Morphology, Sexual and Asexual Reproduction, Pathogenicity and DON Production of Fusarium graminearum. Front Microbiol 2020; 11:545015. [PMID: 33329417 PMCID: PMC7714731 DOI: 10.3389/fmicb.2020.545015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 10/29/2020] [Indexed: 11/29/2022] Open
Abstract
The conserved Dis1/Stu2/XMAP215 microtubule association proteins (MAPs) family plays an important role in microtubule dynamics, nucleation, and kinetochore-microtubule attachments. However, function of Dis1/Stu2/XMAP215 homolog in plant pathogenic fungi has not been determined. Here, we identified and investigated the Dis1/Stu2/XMAP215 homolog (FGSG_10528) in Fusarium graminearum (FgStu2p). Co-localization experiment and co-immunoprecipitation (Co-IP) assay demonstrated that FgStu2p is a microtubule associated protein. Besides, FgStu2 could also interact with Fgγ-tubulin and presumed FgNdc80, which suggested that the FgStu2 gene might associate with microtubule nucleation and kinetochore-microtubule attachments like Dis1/Stu2/XMAP215 homologs in other species. Moreover, the FgStu2 promoter replacement mutants (FgStu2-Si mutants) produced twisted hyphae and decreased growth rate. Microscope examination further showed that the microtubule polymerization was reduced in FgStu2-Si mutants, which could account for the aberrant morphology. Although the microtubule polymerization was affected in FgStu2-Si mutants, the FgStu2-Si mutants didn’t show highly increased sensitivity to anti-microtubule fungicide carbendazim (methyl benzimidazol-2-ylcarbamate [MBC]). In addition, the FgStu2-Si mutants exhibited curved conidia, decreased number of conidial production, blocked ability of perithecia production, decreased pathogenicity and deoxynivalenol (DON) production. Taken together, these results indicate that the FgStu2 gene plays a crucial role in vegetative growth, morphology, sexual reproduction, asexual reproduction, virulence and deoxynivalenol (DON) production of F. graminearum, which brings new insights into the functions of Dis1/Stu2/XMAP215 homolog in plant pathogenic fungi.
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Affiliation(s)
- Yuanye Zhu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yuanshuai Zhang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Na Liu
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Weichao Ren
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Yiping Hou
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yabing Duan
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Xiushi Song
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Mingguo Zhou
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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14
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Zhang Q, Hu L, Chen Y, Tian W, Liu H. Multisite phosphorylation determines the formation of Ska-Ndc80 macro-complexes that are essential for chromosome segregation during mitosis. Mol Biol Cell 2020; 31:1892-1903. [PMID: 32491969 PMCID: PMC7525821 DOI: 10.1091/mbc.e19-10-0569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human Ska complex (Ska) localizing to both spindle microtubules and kinetochores is essential for proper chromosome segregation during mitosis. Although several mechanisms have been proposed to explain how Ska is recruited to kinetochores, it is still not fully understood. By analyzing Ska3 phosphorylation, we identified six critical Cdk1 sites, including the previously identified Thr358 and Thr360. Mutations of these sites to phospho-deficient alanine (6A) in cells completely abolished Ska3 localization to kinetochores and Ska functions in chromosome segregation. In vitro, Cdk1 phosphorylation on Ska enhanced WT, not phospho-deficient 6A, binding to Ndc80C. Strikingly, the phosphomimetic Ska 6D complex formed a stable macro-complex with Ndc80C, but Ska WT failed to do so. These results suggest that multisite Cdk1 phosphorylation-enabled Ska–Ndc80 binding is decisive for Ska localization to kinetochores and its functions. Moreover, we found that Ska decrease at kinetochores triggered by the microtubule-depolymerizing drug nocodazole is independent of Aurora B but can be overridden by Ska3 overexpression, suggestive of a role of spindle microtubules in promoting Ska kinetochore recruitment. Thus, based on the current and previous results, we propose that multisite Cdk1 phosphorylation is critical for the formation of Ska–Ndc80 macro-complexes that are essential for chromosome segregation.
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Affiliation(s)
- Qian Zhang
- Department of Biochemistry and Molecular Biology, Tulane University Health Science Center, New Orleans, LA 70112
| | - Liqiao Hu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yujue Chen
- Department of Biochemistry and Molecular Biology, Tulane University Health Science Center, New Orleans, LA 70112
| | - Wei Tian
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hong Liu
- Department of Biochemistry and Molecular Biology, Tulane University Health Science Center, New Orleans, LA 70112
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15
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Ustinov NB, Korshunova AV, Gudimchuk NB. Protein Complex NDC80: Properties, Functions, and Possible Role in Pathophysiology of Cell Division. BIOCHEMISTRY (MOSCOW) 2020; 85:448-462. [PMID: 32569552 DOI: 10.1134/s0006297920040057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mitotic division maintains genetic identity of any multicellular organism throughout an entire lifetime. Each time a parent cell divides, chromosomes are equally distributed between the daughter cells due to the action of mitotic spindle. Mitotic spindle is formed by the microtubules that represent dynamic polymers of tubulin protein. Spindle microtubules are attached end-on to kinetochores - large multi-protein complexes on chromosomes. This review focuses on the four-subunit NDC80 complex, one of the most important kinetochore elements that plays a major role in the attachment of assembling/disassembling microtubule ends to the chromosomes. Here, we summarize published data on the structure, properties, and regulation of the NDC80 complex and discuss possible relationship between changes in the expression of genes coding for the NDC80 complex components, mitotic disorders, and oncogenesis with special emphasis on the diagnostic and therapeutic potential of NDC80.
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Affiliation(s)
- N B Ustinov
- Center for Theoretical Problems of Physico-Chemical Pharmacology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - A V Korshunova
- Center for Theoretical Problems of Physico-Chemical Pharmacology, Russian Academy of Sciences, Moscow, 119991, Russia.,Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia
| | - N B Gudimchuk
- Center for Theoretical Problems of Physico-Chemical Pharmacology, Russian Academy of Sciences, Moscow, 119991, Russia. .,Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia
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16
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Edelmaier C, Lamson AR, Gergely ZR, Ansari S, Blackwell R, McIntosh JR, Glaser MA, Betterton MD. Mechanisms of chromosome biorientation and bipolar spindle assembly analyzed by computational modeling. eLife 2020; 9:48787. [PMID: 32053104 PMCID: PMC7311174 DOI: 10.7554/elife.48787] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 02/12/2020] [Indexed: 01/19/2023] Open
Abstract
The essential functions required for mitotic spindle assembly and chromosome biorientation and segregation are not fully understood, despite extensive study. To illuminate the combinations of ingredients most important to align and segregate chromosomes and simultaneously assemble a bipolar spindle, we developed a computational model of fission-yeast mitosis. Robust chromosome biorientation requires progressive restriction of attachment geometry, destabilization of misaligned attachments, and attachment force dependence. Large spindle length fluctuations can occur when the kinetochore-microtubule attachment lifetime is long. The primary spindle force generators are kinesin-5 motors and crosslinkers in early mitosis, while interkinetochore stretch becomes important after biorientation. The same mechanisms that contribute to persistent biorientation lead to segregation of chromosomes to the poles after anaphase onset. This model therefore provides a framework to interrogate key requirements for robust chromosome biorientation, spindle length regulation, and force generation in the spindle. Before a cell divides, it must make a copy of its genetic material and then promptly split in two. This process, called mitosis, is coordinated by many different molecular machines. The DNA is copied, then the duplicated chromosomes line up at the middle of the cell. Next, an apparatus called the mitotic spindle latches onto the chromosomes before pulling them apart. The mitotic spindle is a bundle of long, thin filaments called microtubules. It attaches to chromosomes at the kinetochore, the point where two copied chromosomes are cinched together in their middle. Proper cell division is vital for the healthy growth of all organisms, big and small, and yet some parts of the process remain poorly understood despite extensive study. Specifically, there is more to learn about how the mitotic spindle self-assembles, and how microtubules and kinetochores work together to correctly orient and segregate chromosomes into two sister cells. These nanoscale processes are happening a hundred times a minute, so computer simulations are a good way to test what we know. Edelmaier et al. developed a computer model to simulate cell division in fission yeast, a species of yeast often used to study fundamental processes in the cell. The model simulates how the mitotic spindle assembles, how its microtubules attach to the kinetochore and the force required to pull two sister chromosomes apart. Building the simulation involved modelling interactions between the mitotic spindle and kinetochore, their movement and forces applied. To test its accuracy, model simulations were compared to recordings of the mitotic spindle – including its length, structure and position – imaged from dividing yeast cells. Running the simulation, Edelmaier et al. found that several key effects are essential for the proper movement of chromosomes in mitosis. This includes holding chromosomes in the correct orientation as the mitotic spindle assembles and controlling the relative position of microtubules as they attach to the kinetochore. Misaligned attachments must also be readily deconstructed and corrected to prevent any errors. The simulations also showed that kinetochores must begin to exert more force (to separate the chromosomes) once the mitotic spindle is attached correctly. Altogether, these findings improve the current understanding of how the mitotic spindle and its counterparts control cell division. Errors in chromosome segregation are associated with birth defects and cancer in humans, and this new simulation could potentially now be used to help make predictions about how to correct mistakes in the process.
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Affiliation(s)
| | - Adam R Lamson
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - Zachary R Gergely
- Department of Physics, University of Colorado Boulder, Boulder, United States.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Saad Ansari
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - Robert Blackwell
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - J Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Matthew A Glaser
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - Meredith D Betterton
- Department of Physics, University of Colorado Boulder, Boulder, United States.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
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17
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Huis In 't Veld PJ, Volkov VA, Stender ID, Musacchio A, Dogterom M. Molecular determinants of the Ska-Ndc80 interaction and their influence on microtubule tracking and force-coupling. eLife 2019; 8:49539. [PMID: 31804178 PMCID: PMC6927755 DOI: 10.7554/elife.49539] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022] Open
Abstract
Errorless chromosome segregation requires load-bearing attachments of the plus ends of spindle microtubules to chromosome structures named kinetochores. How these end-on kinetochore attachments are established following initial lateral contacts with the microtubule lattice is poorly understood. Two microtubule-binding complexes, the Ndc80 and Ska complexes, are important for efficient end-on coupling and may function as a unit in this process, but precise conditions for their interaction are unknown. Here, we report that the Ska-Ndc80 interaction is phosphorylation-dependent and does not require microtubules, applied force, or several previously identified functional determinants including the Ndc80-loop and the Ndc80-tail. Both the Ndc80-tail, which we reveal to be essential for microtubule end-tracking, and Ndc80-bound Ska stabilize microtubule ends in a stalled conformation. Modulation of force-coupling efficiency demonstrates that the duration of stalled microtubule disassembly predicts whether a microtubule is stabilized and rescued by the kinetochore, likely reflecting a structural transition of the microtubule end.
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Affiliation(s)
- Pim J Huis In 't Veld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Vladimir A Volkov
- Department of Bionanoscience, Faculty of Applied Sciences, Delft University of Technology, Delft, Netherlands
| | - Isabelle D Stender
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.,Centre for Medical Biotechnology, Faculty of Biology, University Duisburg, Essen, Germany
| | - Marileen Dogterom
- Department of Bionanoscience, Faculty of Applied Sciences, Delft University of Technology, Delft, Netherlands
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18
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Two XMAP215/TOG Microtubule Polymerases, Alp14 and Dis1, Play Non-Exchangeable, Distinct Roles in Microtubule Organisation in Fission Yeast. Int J Mol Sci 2019; 20:ijms20205108. [PMID: 31618856 PMCID: PMC6834199 DOI: 10.3390/ijms20205108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/12/2019] [Accepted: 10/12/2019] [Indexed: 12/29/2022] Open
Abstract
Proper bipolar spindle assembly underlies accurate chromosome segregation. A cohort of microtubule-associated proteins orchestrates spindle microtubule formation in a spatiotemporally coordinated manner. Among them, the conserved XMAP215/TOG family of microtubule polymerase plays a central role in spindle assembly. In fission yeast, two XMAP215/TOG members, Alp14 and Dis1, share essential roles in cell viability; however how these two proteins functionally collaborate remains undetermined. Here we show the functional interplay and specification of Alp14 and Dis1. Creation of new mutant alleles of alp14, which display temperature sensitivity in the absence of Dis1, enabled us to conduct detailed analyses of a double mutant. We have found that simultaneous inactivation of Alp14 and Dis1 results in early mitotic arrest with very short, fragile spindles. Intriguingly, these cells often undergo spindle collapse, leading to a lethal “cut” phenotype. By implementing an artificial targeting system, we have shown that Alp14 and Dis1 are not functionally exchangeable and as such are not merely redundant paralogues. Interestingly, while Alp14 promotes microtubule nucleation, Dis1 does not. Our results uncover that the intrinsic specification, not the spatial regulation, between Alp14 and Dis1 underlies the collaborative actions of these two XMAP215/TOG members in mitotic progression, spindle integrity and genome stability.
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19
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Miller MP, Evans RK, Zelter A, Geyer EA, MacCoss MJ, Rice LM, Davis TN, Asbury CL, Biggins S. Kinetochore-associated Stu2 promotes chromosome biorientation in vivo. PLoS Genet 2019; 15:e1008423. [PMID: 31584935 PMCID: PMC6795502 DOI: 10.1371/journal.pgen.1008423] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/16/2019] [Accepted: 09/13/2019] [Indexed: 12/31/2022] Open
Abstract
Accurate segregation of chromosomes to daughter cells is a critical aspect of cell division. It requires the kinetochores on duplicated chromosomes to biorient, attaching to microtubules from opposite poles of the cell. Bioriented attachments come under tension, while incorrect attachments lack tension and must be released to allow proper attachments to form. A well-studied error correction pathway is mediated by the Aurora B kinase, which destabilizes low tension-bearing attachments. We recently discovered that in vitro, kinetochores display an additional intrinsic tension-sensing pathway that utilizes Stu2. The contribution of kinetochore-associated Stu2 to error correction in cells, however, was unknown. Here, we identify a Stu2 mutant that abolishes its kinetochore function and show that it causes biorientation defects in vivo. We also show that this Stu2-mediated pathway functions together with the Aurora B-mediated pathway. Altogether, our work indicates that cells employ multiple pathways to ensure biorientation and the accuracy of chromosome segregation. The precise regulation of cell division is critical to processes such as self-renewal, proliferation and development. A key event in the cell cycle is the partitioning of every pair of duplicated chromosomes to daughter cells. Defects in chromosome partitioning lead to aneuploidy, a condition that is a common hallmark of cancer cells and the cause of some birth defects. Chromosomes segregate using their kinetochores, the specialized protein structures that are assembled on centromeric DNA sequences and attach to spindle microtubules. Here, we report that a protein that associates with kinetochores called Stu2 ensures that each kinetochore attaches to the proper microtubules. We identified a Stu2 mutant that does not associate with kinetochores and found that it generates aneuploidy. Together, our work identifies a previously unknown mechanism where cells ensure that chromosomes are accurately inherited during cell division.
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Affiliation(s)
- Matthew P. Miller
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Rena K. Evans
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Alex Zelter
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States of America
| | - Elisabeth A. Geyer
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Michael J. MacCoss
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Luke M. Rice
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Trisha N. Davis
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States of America
| | - Charles L. Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington, United States of America
| | - Sue Biggins
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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20
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Pinder C, Matsuo Y, Maurer SP, Toda T. Kinesin-8 and Dis1/TOG collaborate to limit spindle elongation from prophase to anaphase A for proper chromosome segregation in fission yeast. J Cell Sci 2019; 132:jcs232306. [PMID: 31427431 PMCID: PMC6765184 DOI: 10.1242/jcs.232306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/09/2019] [Indexed: 12/15/2022] Open
Abstract
High-fidelity chromosome segregation relies on proper microtubule regulation. Kinesin-8 has been shown to destabilise microtubules to reduce metaphase spindle length and chromosome movements in multiple species. XMAP215/chTOG polymerases catalyse microtubule growth for spindle assembly, elongation and kinetochore-microtubule attachment. Understanding of their biochemical activity has advanced, but little work directly addresses the functionality and interplay of these conserved factors. We utilised the synthetic lethality of fission yeast kinesin-8 (Klp5-Klp6) and XMAP215/chTOG (Dis1) to study their individual and overlapping roles. We found that the non-motor kinesin-8 tailbox is essential for mitotic function; mutation compromises plus-end-directed processivity. Klp5-Klp6 induces catastrophes to control microtubule length and, surprisingly, Dis1 collaborates with kinesin-8 to slow spindle elongation. Together, they enforce a maximum spindle length for a viable metaphase-anaphase transition and limit elongation during anaphase A to prevent lagging chromatids. Our work provides mechanistic insight into how kinesin-8 negatively regulates microtubules and how this functionally overlaps with Dis1 and highlights the importance of spindle length control in mitosis.
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Affiliation(s)
- Corinne Pinder
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Division of Biological and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Yuzy Matsuo
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Sebastian P Maurer
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
| | - Takashi Toda
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Division of Biological and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Hiroshima Research Center for Healthy Aging (HiHA), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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21
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Amin MA, Agarwal S, Varma D. Mapping the kinetochore MAP functions required for stabilizing microtubule attachments to chromosomes during metaphase. Cytoskeleton (Hoboken) 2019; 76:398-412. [PMID: 31454167 DOI: 10.1002/cm.21559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 08/07/2019] [Accepted: 08/22/2019] [Indexed: 12/24/2022]
Abstract
In mitosis, faithful chromosome segregation is orchestrated by the dynamic interactions between the spindle microtubules (MTs) emanating from the opposite poles and the kinetochores of the chromosomes. However, the precise mechanism that coordinates the coupling of the kinetochore components to dynamic MTs has been a long-standing question. Microtubule-associated proteins (MAPs) regulate MT nucleation and dynamics, MT-mediated transport and MT cross-linking in cells. During mitosis, MAPs play an essential role not only in determining spindle length, position, and orientation but also in facilitating robust kinetochore-microtubule (kMT) attachments by linking the kinetochores to spindle MTs efficiently. The stability of MTs imparted by the MAPs is critical to ensure accurate chromosome segregation. This review primarily focuses on the specific function of nonmotor kinetochore MAPs, their recruitment to kinetochores and their MT-binding properties. We also attempt to synthesize and strengthen our understanding of how these MAPs work in coordination with the kinetochore-bound Ndc80 complex (the key component at the MT-binding interface in metaphase and anaphase) to establish stable kMT attachments and control accurate chromosome segregation during mitosis.
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Affiliation(s)
- Mohammed A Amin
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Shivangi Agarwal
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Dileep Varma
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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22
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Llauró A, Hayashi H, Bailey ME, Wilson A, Ludzia P, Asbury CL, Akiyoshi B. The kinetoplastid kinetochore protein KKT4 is an unconventional microtubule tip-coupling protein. J Cell Biol 2018; 217:3886-3900. [PMID: 30209069 PMCID: PMC6219724 DOI: 10.1083/jcb.201711181] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 07/23/2018] [Accepted: 08/24/2018] [Indexed: 01/08/2023] Open
Abstract
The evolutionarily divergent class of kinetoplastid organisms has a set of unconventional kinetochore proteins that drive chromosome segregation, but it is unclear which components interact with spindle microtubules. Llauró et al. now identify KKT4 as the first microtubule-binding kinetochore protein in Trypanosoma brucei, a major human pathogenic parasite. Kinetochores are multiprotein machines that drive chromosome segregation by maintaining persistent, load-bearing linkages between chromosomes and dynamic microtubule tips. Kinetochores in commonly studied eukaryotes bind microtubules through widely conserved components like the Ndc80 complex. However, in evolutionarily divergent kinetoplastid species such as Trypanosoma brucei, which causes sleeping sickness, the kinetochores assemble from a unique set of proteins lacking homology to any known microtubule-binding domains. Here, we show that the T. brucei kinetochore protein KKT4 binds directly to microtubules and maintains load-bearing attachments to both growing and shortening microtubule tips. The protein localizes both to kinetochores and to spindle microtubules in vivo, and its depletion causes defects in chromosome segregation. We define a microtubule-binding domain within KKT4 and identify several charged residues important for its microtubule-binding activity. Thus, despite its lack of significant similarity to other known microtubule-binding proteins, KKT4 has key functions required for driving chromosome segregation. We propose that it represents a primary element of the kinetochore–microtubule interface in kinetoplastids.
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Affiliation(s)
- Aida Llauró
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Hanako Hayashi
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Megan E Bailey
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Alex Wilson
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Patryk Ludzia
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Bungo Akiyoshi
- Department of Biochemistry, University of Oxford, Oxford, UK
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23
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Agarwal S, Smith KP, Zhou Y, Suzuki A, McKenney RJ, Varma D. Cdt1 stabilizes kinetochore-microtubule attachments via an Aurora B kinase-dependent mechanism. J Cell Biol 2018; 217:3446-3463. [PMID: 30154187 PMCID: PMC6168275 DOI: 10.1083/jcb.201705127] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 02/06/2018] [Accepted: 07/17/2018] [Indexed: 12/03/2022] Open
Abstract
Cdt1 is a novel kinetochore–microtubule binding protein. The middle and the C-terminal winged-helix domains of Cdt1 are involved in microtubule binding. Aurora B kinase phosphorylation of Cdt1 influences its microtubule binding in vitro and is necessary for kinetochore–microtubule stability and mitotic progression in cells. Robust kinetochore–microtubule (kMT) attachment is critical for accurate chromosome segregation. G2/M-specific depletion of human Cdt1 that localizes to kinetochores in an Ndc80 complex–dependent manner leads to abnormal kMT attachments and mitotic arrest. This indicates an independent mitotic role for Cdt1 in addition to its prototypic function in DNA replication origin licensing. Here, we show that Cdt1 directly binds to microtubules (MTs). Endogenous or transiently expressed Cdt1 localizes to both mitotic spindle MTs and kinetochores. Deletion mapping of Cdt1 revealed that the regions comprising the middle and C-terminal winged-helix domains but lacking the N-terminal unstructured region were required for efficient MT binding. Mitotic kinase Aurora B interacts with and phosphorylates Cdt1. Aurora B–phosphomimetic Cdt1 exhibited attenuated MT binding, and its cellular expression induced defective kMT attachments with a concomitant delay in mitotic progression. Thus we provide mechanistic insight into how Cdt1 affects overall kMT stability in an Aurora B kinase phosphorylation-dependent manner; which is envisioned to augment the MT-binding of the Ndc80 complex.
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Affiliation(s)
- Shivangi Agarwal
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Kyle Paul Smith
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Yizhuo Zhou
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Aussie Suzuki
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Richard J McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA
| | - Dileep Varma
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
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24
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Hayles J, Nurse P. Introduction to Fission Yeast as a Model System. Cold Spring Harb Protoc 2018; 2018:pdb.top079749. [PMID: 28733415 DOI: 10.1101/pdb.top079749] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Here, we briefly outline the history of fission yeast, its life cycle, and aspects of its biology that make it a useful model organism for studying problems of eukaryotic molecular and cell biology.
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Affiliation(s)
- Jacqueline Hayles
- Cell Cycle Laboratory, The Francis Crick Research Institute, London WC2A 3LY, United Kingdom
| | - Paul Nurse
- Cell Cycle Laboratory, The Francis Crick Research Institute, London WC2A 3LY, United Kingdom
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25
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Haase KP, Fox JC, Byrnes AE, Adikes RC, Speed SK, Haase J, Friedman B, Cook DM, Bloom K, Rusan NM, Slep KC. Stu2 uses a 15-nm parallel coiled coil for kinetochore localization and concomitant regulation of the mitotic spindle. Mol Biol Cell 2018; 29:285-294. [PMID: 29187574 PMCID: PMC5996958 DOI: 10.1091/mbc.e17-01-0057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 10/10/2017] [Accepted: 11/22/2017] [Indexed: 11/23/2022] Open
Abstract
XMAP215/Dis1 family proteins are potent microtubule polymerases, critical for mitotic spindle structure and dynamics. While microtubule polymerase activity is driven by an N-terminal tumor overexpressed gene (TOG) domain array, proper cellular localization is a requisite for full activity and is mediated by a C-terminal domain. Structural insight into the C-terminal domain's architecture and localization mechanism remain outstanding. We present the crystal structure of the Saccharomyces cerevisiae Stu2 C-terminal domain, revealing a 15-nm parallel homodimeric coiled coil. The parallel architecture of the coiled coil has mechanistic implications for the arrangement of the homodimer's N-terminal TOG domains during microtubule polymerization. The coiled coil has two spatially distinct conserved regions: CRI and CRII. Mutations in CRI and CRII perturb the distribution and localization of Stu2 along the mitotic spindle and yield defects in spindle morphology including increased frequencies of mispositioned and fragmented spindles. Collectively, these data highlight roles for the Stu2 dimerization domain as a scaffold for factor binding that optimally positions Stu2 on the mitotic spindle to promote proper spindle structure and dynamics.
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Affiliation(s)
- Karen P Haase
- Molecular and Cellular Biophysics Program, University of North Carolina, Chapel Hill, NC 27599
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jaime C Fox
- Molecular and Cellular Biophysics Program, University of North Carolina, Chapel Hill, NC 27599
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Amy E Byrnes
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Rebecca C Adikes
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599
| | - Sarah K Speed
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599
| | - Julian Haase
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599
| | - Brandon Friedman
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599
| | - Diana M Cook
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599
| | - Kerry Bloom
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599
| | - Nasser M Rusan
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Kevin C Slep
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599
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26
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Yukawa M, Kawakami T, Okazaki M, Kume K, Tang NH, Toda T. A microtubule polymerase cooperates with the kinesin-6 motor and a microtubule cross-linker to promote bipolar spindle assembly in the absence of kinesin-5 and kinesin-14 in fission yeast. Mol Biol Cell 2017; 28:3647-3659. [PMID: 29021344 PMCID: PMC5706992 DOI: 10.1091/mbc.e17-08-0497] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/26/2017] [Accepted: 10/03/2017] [Indexed: 12/16/2022] Open
Abstract
Kinesin-5 is required for bipolar spindle assembly; yet in the absence of kinesins-5 and -14, cells can form spindles. In fission yeast, three distinct pathways compensate for their loss. Microtubule polymerase, kinesin-6, and microtubule cross-linker execute individual roles in concert at different mitotic stages in place of the two kinesins. Accurate chromosome segregation relies on the bipolar mitotic spindle. In many eukaryotes, spindle formation is driven by the plus-end–directed motor kinesin-5 that generates outward force to establish spindle bipolarity. Its inhibition leads to the emergence of monopolar spindles with mitotic arrest. Intriguingly, simultaneous inactivation of the minus-end–directed motor kinesin-14 restores spindle bipolarity in many systems. Here we show that in fission yeast, three independent pathways contribute to spindle bipolarity in the absence of kinesin-5/Cut7 and kinesin-14/Pkl1. One is kinesin-6/Klp9 that engages with spindle elongation once short bipolar spindles assemble. Klp9 also ensures the medial positioning of anaphase spindles to prevent unequal chromosome segregation. Another is the Alp7/TACC-Alp14/TOG microtubule polymerase complex. Temperature-sensitive alp7cut7pkl1 mutants are arrested with either monopolar or very short spindles. Forced targeting of Alp14 to the spindle pole body is sufficient to render alp7cut7pkl1 triply deleted cells viable and promote spindle assembly, indicating that Alp14-mediated microtubule polymerization from the nuclear face of the spindle pole body could generate outward force in place of Cut7 during early mitosis. The third pathway involves the Ase1/PRC1 microtubule cross-linker that stabilizes antiparallel microtubules. Our study, therefore, unveils multifaceted interplay among kinesin-dependent and -independent pathways leading to mitotic bipolar spindle assembly.
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Affiliation(s)
- Masashi Yukawa
- Hiroshima Research Center for Healthy Aging, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan .,Laboratory of Molecular and Chemical Cell Biology, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Tomoki Kawakami
- Hiroshima Research Center for Healthy Aging, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan.,Laboratory of Molecular and Chemical Cell Biology, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Masaki Okazaki
- Hiroshima Research Center for Healthy Aging, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan.,Laboratory of Molecular and Chemical Cell Biology, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Kazunori Kume
- Hiroshima Research Center for Healthy Aging, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan.,Laboratory of Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Ngang Heok Tang
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Takashi Toda
- Hiroshima Research Center for Healthy Aging, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan .,Laboratory of Molecular and Chemical Cell Biology, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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27
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Shrestha RL, Conti D, Tamura N, Braun D, Ramalingam RA, Cieslinski K, Ries J, Draviam VM. Aurora-B kinase pathway controls the lateral to end-on conversion of kinetochore-microtubule attachments in human cells. Nat Commun 2017; 8:150. [PMID: 28751710 PMCID: PMC5532248 DOI: 10.1038/s41467-017-00209-z] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 06/12/2017] [Indexed: 12/29/2022] Open
Abstract
Human chromosomes are captured along microtubule walls (lateral attachment) and then tethered to microtubule-ends (end-on attachment) through a multi-step end-on conversion process. Upstream regulators that orchestrate this remarkable change in the plane of kinetochore-microtubule attachment in human cells are not known. By tracking kinetochore movements and using kinetochore markers specific to attachment status, we reveal a spatially defined role for Aurora-B kinase in retarding the end-on conversion process. To understand how Aurora-B activity is counteracted, we compare the roles of two outer-kinetochore bound phosphatases and find that BubR1-associated PP2A, unlike KNL1-associated PP1, plays a significant role in end-on conversion. Finally, we uncover a novel role for Aurora-B regulated Astrin-SKAP complex in ensuring the correct plane of kinetochore-microtubule attachment. Thus, we identify Aurora-B as a key upstream regulator of end-on conversion in human cells and establish a late role for Astrin-SKAP complex in the end-on conversion process.Human chromosomes are captured along microtubule walls and then tethered to microtubule-ends through a multi-step end-on conversion process. Here the authors show that Aurora-B regulates end-on conversion in human cells and establish a late role for Astrin-SKAP complex in the end-on conversion process.
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Affiliation(s)
- Roshan L Shrestha
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Duccio Conti
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Naoka Tamura
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
- Barts Cancer Institute, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Dominique Braun
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
| | - Revathy A Ramalingam
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Konstanty Cieslinski
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstrasse 1, Heidelberg, Germany
| | - Jonas Ries
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstrasse 1, Heidelberg, Germany
| | - Viji M Draviam
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.
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28
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The unconventional kinetoplastid kinetochore: from discovery toward functional understanding. Biochem Soc Trans 2017; 44:1201-1217. [PMID: 27911702 PMCID: PMC5095916 DOI: 10.1042/bst20160112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/15/2016] [Accepted: 06/21/2016] [Indexed: 11/17/2022]
Abstract
The kinetochore is the macromolecular protein complex that drives chromosome segregation in eukaryotes. Its most fundamental function is to connect centromeric DNA to dynamic spindle microtubules. Studies in popular model eukaryotes have shown that centromere protein (CENP)-A is critical for DNA-binding, whereas the Ndc80 complex is essential for microtubule-binding. Given their conservation in diverse eukaryotes, it was widely believed that all eukaryotes would utilize these components to make up a core of the kinetochore. However, a recent study identified an unconventional type of kinetochore in evolutionarily distant kinetoplastid species, showing that chromosome segregation can be achieved using a distinct set of proteins. Here, I review the discovery of the two kinetochore systems and discuss how their studies contribute to a better understanding of the eukaryotic chromosome segregation machinery.
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29
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Kinesin-5-independent mitotic spindle assembly requires the antiparallel microtubule crosslinker Ase1 in fission yeast. Nat Commun 2017; 8:15286. [PMID: 28513584 PMCID: PMC5442317 DOI: 10.1038/ncomms15286] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 03/13/2017] [Indexed: 12/04/2022] Open
Abstract
Bipolar spindle assembly requires a balance of forces where kinesin-5 produces outward pushing forces to antagonize the inward pulling forces from kinesin-14 or dynein. Accordingly, Kinesin-5 inactivation results in force imbalance leading to monopolar spindle and chromosome segregation failure. In fission yeast, force balance is restored when both kinesin-5 Cut7 and kinesin-14 Pkl1 are deleted, restoring spindle bipolarity. Here we show that the cut7Δpkl1Δ spindle is fully competent for chromosome segregation independently of motor activity, except for kinesin-6 Klp9, which is required for anaphase spindle elongation. We demonstrate that cut7Δpkl1Δ spindle bipolarity requires the microtubule antiparallel bundler PRC1/Ase1 to recruit CLASP/Cls1 to stabilize microtubules. Brownian dynamics-kinetic Monte Carlo simulations show that Ase1 and Cls1 activity are sufficient for initial bipolar spindle formation. We conclude that pushing forces generated by microtubule polymerization are sufficient to promote spindle pole separation and the assembly of bipolar spindle in the absence of molecular motors. Bipolar spindle assembly requires a balance of kinesin 14 pulling and kinesin 5 pushing forces. Here, the authors show that in fission yeast, spindle formation can occur in the absence of kinesin 5 (Cut7) and 14 (Pkl1) but requires the microtubule-associated protein Ase1 for spindle bipolarity.
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30
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Byrnes AE, Slep KC. TOG-tubulin binding specificity promotes microtubule dynamics and mitotic spindle formation. J Cell Biol 2017; 216:1641-1657. [PMID: 28512144 PMCID: PMC5461023 DOI: 10.1083/jcb.201610090] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/02/2017] [Accepted: 04/26/2017] [Indexed: 11/24/2022] Open
Abstract
Microtubule-associated proteins with arrays of TOG domains differentially regulate microtubule dynamics. Byrnes and Slep show that TOG arrays are polarized containing architecturally distinct TOG domains that bind either free or microtubule lattice-incorporated tubulin, which is essential for microtubule polymerization and mitotic spindle formation. XMAP215, CLASP, and Crescerin use arrayed tubulin-binding tumor overexpressed gene (TOG) domains to modulate microtubule dynamics. We hypothesized that TOGs have distinct architectures and tubulin-binding properties that underlie each family’s ability to promote microtubule polymerization or pause. As a model, we investigated the pentameric TOG array of a Drosophila melanogaster XMAP215 member, Msps. We found that Msps TOGs have distinct architectures that bind either free or polymerized tubulin, and that a polarized array drives microtubule polymerization. An engineered TOG1-2-5 array fully supported Msps-dependent microtubule polymerase activity. Requisite for this activity was a TOG5-specific N-terminal HEAT repeat that engaged microtubule lattice-incorporated tubulin. TOG5–microtubule binding maintained mitotic spindle formation as deleting or mutating TOG5 compromised spindle architecture and increased the mitotic index. Mad2 knockdown released the spindle assembly checkpoint triggered when TOG5–microtubule binding was compromised, indicating that TOG5 is essential for spindle function. Our results reveal a TOG5-specific role in mitotic fidelity and support our hypothesis that architecturally distinct TOGs arranged in a sequence-specific order underlie TOG array microtubule regulator activity.
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Affiliation(s)
- Amy E Byrnes
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599.,Program in Molecular and Cellular Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Kevin C Slep
- Program in Molecular and Cellular Biophysics, University of North Carolina, Chapel Hill, NC 27599 .,Department of Biology, University of North Carolina, Chapel Hill, NC 27599
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31
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Matsuo Y, Maurer SP, Surrey T, Toda T. Purification and characterisation of the fission yeast Ndc80 complex. Protein Expr Purif 2017; 135:61-69. [PMID: 28502666 PMCID: PMC5489075 DOI: 10.1016/j.pep.2017.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/07/2017] [Accepted: 05/08/2017] [Indexed: 12/02/2022]
Abstract
The Ndc80 complex is a conserved outer kinetochore protein complex consisting of Ndc80 (Hec1), Nuf2, Spc24 and Spc25. This complex comprises a major, if not the sole, platform with which the plus ends of the spindle microtubules directly interact. In fission yeast, several studies indicate that multiple microtubule-associated proteins including the Dis1/chTOG microtubule polymerase and the Mal3/EB1 microtubule plus-end tracking protein directly or indirectly bind Ndc80, thereby ensuring stable kinetochore-microtubule attachment. However, the purification of the Ndc80 complex from this yeast has not been achieved, which hampers the in-depth investigation as to how the outer kinetochore attaches to the plus end of the spindle microtubule. Here we report the two-step purification of the fission yeast Ndc80 holo complex from bacteria. First, we purified separately two sub-complexes consisting of Ndc80-Nuf2 and Spc24-Spc25. Then, these two sub-complexes were mixed and applied to size-exclusion chromatography. The reconstituted Ndc80 holo complex is composed of four subunits with equal stoichiometry. The complex possesses microtubule-binding activity, and Total Internal Reflection Fluorescence (TIRF)-microscopy assays show that the complex binds the microtubule lattice. Interestingly, unlike the human complex, the fission yeast complex does not track depolymerising microtubule ends. Further analysis shows that under physiological ionic conditions, the Ndc80 holo complex does not detectably bind Dis1, but instead it interacts with Mal3/EB1, by which the Ndc80 complex tracks the growing microtubule plus end. This result substantiates the notion that the Ndc80 complex plays a crucial role in establishment of the dynamic kinetochore-microtubule interface by cooperating with chTOG and EB1. The Ndc80 complex is a conserved outer kinetochore complex. The fission yeast Ndc80 complex is purified from bacteria through a two-step purification scheme. The Ndc80 complex possesses microtubule-binding activity similar to those from other species. TIRF-microscopy assays show that the complex binds the microtubule lattice. The Ndc80 complex tracks the microtubule plus end when mixed with Mal3/EB1.
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Affiliation(s)
- Yuzy Matsuo
- Cell Regulation Laboratory, The Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK; Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Sebastian P Maurer
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK; Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Thomas Surrey
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
| | - Takashi Toda
- Cell Regulation Laboratory, The Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK; Hiroshima Research Center for Healthy Aging (HiHA), Department of Molecular Biotechnology, Graduate School of Advanced Science of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan.
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32
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Asbury CL. Anaphase A: Disassembling Microtubules Move Chromosomes toward Spindle Poles. BIOLOGY 2017; 6:E15. [PMID: 28218660 PMCID: PMC5372008 DOI: 10.3390/biology6010015] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/04/2017] [Accepted: 02/10/2017] [Indexed: 11/16/2022]
Abstract
The separation of sister chromatids during anaphase is the culmination of mitosis and one of the most strikingly beautiful examples of cellular movement. It consists of two distinct processes: Anaphase A, the movement of chromosomes toward spindle poles via shortening of the connecting fibers, and anaphase B, separation of the two poles from one another via spindle elongation. I focus here on anaphase A chromosome-to-pole movement. The chapter begins by summarizing classical observations of chromosome movements, which support the current understanding of anaphase mechanisms. Live cell fluorescence microscopy studies showed that poleward chromosome movement is associated with disassembly of the kinetochore-attached microtubule fibers that link chromosomes to poles. Microtubule-marking techniques established that kinetochore-fiber disassembly often occurs through loss of tubulin subunits from the kinetochore-attached plus ends. In addition, kinetochore-fiber disassembly in many cells occurs partly through 'flux', where the microtubules flow continuously toward the poles and tubulin subunits are lost from minus ends. Molecular mechanistic models for how load-bearing attachments are maintained to disassembling microtubule ends, and how the forces are generated to drive these disassembly-coupled movements, are discussed.
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Affiliation(s)
- Charles L Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, USA.
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33
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Blackwell R, Edelmaier C, Sweezy-Schindler O, Lamson A, Gergely ZR, O’Toole E, Crapo A, Hough LE, McIntosh JR, Glaser MA, Betterton MD. Physical determinants of bipolar mitotic spindle assembly and stability in fission yeast. SCIENCE ADVANCES 2017; 3:e1601603. [PMID: 28116355 PMCID: PMC5249259 DOI: 10.1126/sciadv.1601603] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 12/05/2016] [Indexed: 05/10/2023]
Abstract
Mitotic spindles use an elegant bipolar architecture to segregate duplicated chromosomes with high fidelity. Bipolar spindles form from a monopolar initial condition; this is the most fundamental construction problem that the spindle must solve. Microtubules, motors, and cross-linkers are important for bipolarity, but the mechanisms necessary and sufficient for spindle assembly remain unknown. We describe a physical model that exhibits de novo bipolar spindle formation. We began with physical properties of fission-yeast spindle pole body size and microtubule number, kinesin-5 motors, kinesin-14 motors, and passive cross-linkers. Our model results agree quantitatively with our experiments in fission yeast, thereby establishing a minimal system with which to interrogate collective self-assembly. By varying the features of our model, we identify a set of functions essential for the generation and stability of spindle bipolarity. When kinesin-5 motors are present, their bidirectionality is essential, but spindles can form in the presence of passive cross-linkers alone. We also identify characteristic failed states of spindle assembly-the persistent monopole, X spindle, separated asters, and short spindle, which are avoided by the creation and maintenance of antiparallel microtubule overlaps. Our model can guide the identification of new, multifaceted strategies to induce mitotic catastrophes; these would constitute novel strategies for cancer chemotherapy.
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Affiliation(s)
- Robert Blackwell
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
- PULS Group, Department of Physics and Cluster of Excellence: Engineering of Advanced Materials, Friedrich-Alexander University Erlangen-Nurnberg, Nagelsbachstr. 49b, Erlangen, Germany
| | | | | | - Adam Lamson
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Zachary R. Gergely
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Eileen O’Toole
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Ammon Crapo
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Loren E. Hough
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - J. Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Matthew A. Glaser
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Meredith D. Betterton
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
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Chmielewska AE, Tang NH, Toda T. The hairpin region of Ndc80 is important for the kinetochore recruitment of Mph1/MPS1 in fission yeast. Cell Cycle 2016; 15:740-7. [PMID: 26900649 PMCID: PMC4845937 DOI: 10.1080/15384101.2016.1148842] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The establishment of proper kinetochore-microtubule attachments facilitates faithful chromosome segregation. Incorrect attachments activate the spindle assembly checkpoint (SAC), which blocks anaphase onset via recruitment of a cohort of SAC components (Mph1/MPS1, Mad1, Mad2, Mad3/BubR1, Bub1 and Bub3) to kinetochores. KNL1, a component of the outer kinetochore KMN network (KNL1/Mis12 complex/Ndc80 complex), acts as a platform for Bub1 and Bub3 localization upon its phosphorylation by Mph1/MPS1. The Ndc80 protein, a major microtubule-binding site, is critical for MPS1 localization to the kinetochores in mammalian cells. Here we characterized the newly isolated mutant ndc80-AK01 in fission yeast, which contains a single point mutation within the hairpin region. This hairpin connects the preceding calponin-homology domain with the coiled-coil region. ndc80-AK01 was hypersensitive to microtubule depolymerizing reagents with no apparent growth defects without drugs. Subsequent analyses indicated that ndc80-AK01 is defective in SAC signaling, as mutant cells proceeded into lethal cell division in the absence of microtubules. Under mitotic arrest conditions, all SAC components (Ark1/Aurora B, Mph1, Bub1, Bub3, Mad3, Mad2 and Mad1) did not localize to the kinetochore. Further genetic analyses indicated that the Ndc80 hairpin region might act as a platform for the kinetochore recruitment of Mph1, which is one of the most upstream SAC components in the hierarchy. Intriguingly, artificial tethering of Mph1 to the kinetochore fully restored checkpoint signaling in ndc80-AK01 cells, further substantiating the notion that Ndc80 is a kinetochore platform for Mph1. The hairpin region of Ndc80, therefore, plays a critical role in kinetochore recruitment of Mph1.
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Affiliation(s)
| | - Ngang Heok Tang
- a The Francis Crick Institute, Lincoln's Inn Fields , London , United Kingdom
| | - Takashi Toda
- a The Francis Crick Institute, Lincoln's Inn Fields , London , United Kingdom.,b Hiroshima Research Center for Healthy Aging (HiHA), Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University , Higashi-Hiroshima , Japan
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35
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Matsuo Y, Maurer SP, Yukawa M, Zakian S, Singleton MR, Surrey T, Toda T. An unconventional interaction between Dis1/TOG and Mal3/EB1 in fission yeast promotes the fidelity of chromosome segregation. J Cell Sci 2016; 129:4592-4606. [PMID: 27872152 PMCID: PMC5201023 DOI: 10.1242/jcs.197533] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 11/09/2016] [Indexed: 12/31/2022] Open
Abstract
Dynamic microtubule plus-ends interact with various intracellular target regions such as the cell cortex and the kinetochore. Two conserved families of microtubule plus-end-tracking proteins, the XMAP215, ch-TOG or CKAP5 family and the end-binding 1 (EB1, also known as MAPRE1) family, play pivotal roles in regulating microtubule dynamics. Here, we study the functional interplay between fission yeast Dis1, a member of the XMAP215/TOG family, and Mal3, an EB1 protein. Using an in vitro microscopy assay, we find that purified Dis1 autonomously tracks growing microtubule ends and is a bona fide microtubule polymerase. Mal3 recruits additional Dis1 to microtubule ends, explaining the synergistic enhancement of microtubule dynamicity by these proteins. A non-canonical binding motif in Dis1 mediates the interaction with Mal3. X-ray crystallography shows that this new motif interacts in an unconventional configuration with the conserved hydrophobic cavity formed within the Mal3 C-terminal region that typically interacts with the canonical SXIP motif. Selectively perturbing the Mal3-Dis1 interaction in living cells demonstrates that it is important for accurate chromosome segregation. Whereas, in some metazoans, the interaction between EB1 and the XMAP215/TOG family members requires an additional binding partner, fission yeast relies on a direct interaction, indicating evolutionary plasticity of this critical interaction module.
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Affiliation(s)
- Yuzy Matsuo
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Cell Regulation Laboratory, The Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Sebastian P Maurer
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Cell and Developmental Biology, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain
| | - Masashi Yukawa
- Hiroshima Research Center for Healthy Aging (HiHA), Department of Molecular Biotechnology, Graduate School of Advanced Science of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan
| | - Silva Zakian
- Structural Biology of Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Martin R Singleton
- Structural Biology of Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Thomas Surrey
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Takashi Toda
- Cell Regulation Laboratory, The Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
- Hiroshima Research Center for Healthy Aging (HiHA), Department of Molecular Biotechnology, Graduate School of Advanced Science of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan
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36
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John Gagliardi L, Shain DH. Electrostatic forces drive poleward chromosome motions at kinetochores. Cell Div 2016; 11:14. [PMID: 27807465 PMCID: PMC5086063 DOI: 10.1186/s13008-016-0026-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/16/2016] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Recent experiments regarding Ndc80/Hec1 in force generation at kinetochores for chromosome motions have prompted speculation about possible models for interactions between positively charged molecules at kinetochores and negative charge at and near the plus ends of microtubules. DISCUSSION A clear picture of how kinetochores and centrosomes establish and maintain a dynamic coupling to microtubules for force generation during the complex motions of mitosis remains elusive. The current paradigm of molecular cell biology requires that specific molecules, or molecular geometries, for force generation be identified. However, it is possible to explain several different mitotic motions-including poleward force production at kinetochores-within a classical electrostatics approach in terms of experimentally known charge distributions, modeled as surface and volume bound charges interacting over nanometer distances. CONCLUSION We propose here that implicating Ndc80/Hec1 as a bound volume positive charge distribution in electrostatic generation of poleward force at kinetochores is most consistent with a wide range of experimental observations on mitotic motions, including polar production of poleward force and chromosome congression.
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Affiliation(s)
- L. John Gagliardi
- Departments of Physics and Biology, Rutgers The State University of New Jersey, Camden, NJ 08102 USA
| | - Daniel H. Shain
- Departments of Physics and Biology, Rutgers The State University of New Jersey, Camden, NJ 08102 USA
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37
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Roche B, Arcangioli B, Martienssen RA. RNA interference is essential for cellular quiescence. Science 2016; 354:science.aah5651. [PMID: 27738016 DOI: 10.1126/science.aah5651] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/27/2016] [Indexed: 12/19/2022]
Abstract
Quiescent cells play a predominant role in most organisms. Here we identify RNA interference (RNAi) as a major requirement for quiescence (G0 phase of the cell cycle) in Schizosaccharomyces pombe RNAi mutants lose viability at G0 entry and are unable to maintain long-term quiescence. We identified suppressors of G0 defects in cells lacking Dicer (dcr1Δ), which mapped to genes involved in chromosome segregation, RNA polymerase-associated factors, and heterochromatin formation. We propose a model in which RNAi promotes the release of RNA polymerase in cycling and quiescent cells: (i) RNA polymerase II release mediates heterochromatin formation at centromeres, allowing proper chromosome segregation during mitotic growth and G0 entry, and (ii) RNA polymerase I release prevents heterochromatin formation at ribosomal DNA during quiescence maintenance. Our model may account for the codependency of RNAi and histone H3 lysine 9 methylation throughout eukaryotic evolution.
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Affiliation(s)
- B Roche
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - B Arcangioli
- Dynamics of the Genome Unit, Department of Genomes and Genetics, Institut Pasteur, UMR3525, 25-28 rue du Docteur Roux, Paris 75015, France
| | - R A Martienssen
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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38
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Cheerambathur DK, Prevo B, Desai A. A TOGgle for Tension at Kinetochores. Cell 2016; 165:1316-1318. [PMID: 27259144 DOI: 10.1016/j.cell.2016.05.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Differential stability of kinetochore-microtubule attachments at low versus high tension is critical for accurate chromosome segregation. Miller et al. find that a TOG domain microtubule-binding protein imparts intrinsic tension selectivity to kinetochore-microtubule attachments.
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Affiliation(s)
- Dhanya K Cheerambathur
- Department of Cellular & Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA; Ludwig Institute for Cancer Research, San Diego, CA 92093, USA
| | - Bram Prevo
- Department of Cellular & Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA; Ludwig Institute for Cancer Research, San Diego, CA 92093, USA
| | - Arshad Desai
- Department of Cellular & Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA; Ludwig Institute for Cancer Research, San Diego, CA 92093, USA.
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Miller MP, Asbury CL, Biggins S. A TOG Protein Confers Tension Sensitivity to Kinetochore-Microtubule Attachments. Cell 2016; 165:1428-1439. [PMID: 27156448 DOI: 10.1016/j.cell.2016.04.030] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/25/2016] [Accepted: 04/07/2016] [Indexed: 01/10/2023]
Abstract
The development and survival of all organisms depends on equal partitioning of their genomes during cell division. Accurate chromosome segregation requires selective stabilization of kinetochore-microtubule attachments that come under tension due to opposing pulling forces exerted on sister kinetochores by dynamic microtubule tips. Here, we show that the XMAP215 family member, Stu2, makes a major contribution to kinetochore-microtubule coupling. Stu2 and its human ortholog, ch-TOG, exhibit a conserved interaction with the Ndc80 kinetochore complex that strengthens its attachment to microtubule tips. Strikingly, Stu2 can either stabilize or destabilize kinetochore attachments, depending on the level of kinetochore tension and whether the microtubule tip is assembling or disassembling. These dichotomous effects of Stu2 are independent of its previously studied regulation of microtubule dynamics. Altogether, our results demonstrate how a kinetochore-associated factor can confer opposing, tension-dependent effects to selectively stabilize tension-bearing attachments, providing mechanistic insight into the basis for accuracy during chromosome segregation.
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Affiliation(s)
- Matthew P Miller
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Charles L Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, USA.
| | - Sue Biggins
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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40
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Gergely ZR, Crapo A, Hough LE, McIntosh JR, Betterton MD. Kinesin-8 effects on mitotic microtubule dynamics contribute to spindle function in fission yeast. Mol Biol Cell 2016; 27:3490-3514. [PMID: 27146110 PMCID: PMC5221583 DOI: 10.1091/mbc.e15-07-0505] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 04/26/2016] [Indexed: 11/17/2022] Open
Abstract
Kinesin-8 motor proteins destabilize microtubules and increase chromosome loss in mitosis. In fission yeast, aberrant microtubule-driven kinetochore pushing movements, tripolar mitotic spindles, and fluctuations in metaphase spindle length occurred in kinesin-8–deletion mutants. A mathematical model can explain these results. Kinesin-8 motor proteins destabilize microtubules. Their absence during cell division is associated with disorganized mitotic chromosome movements and chromosome loss. Despite recent work studying effects of kinesin-8s on microtubule dynamics, it remains unclear whether the kinesin-8 mitotic phenotypes are consequences of their effect on microtubule dynamics, their well-established motor activity, or additional, unknown functions. To better understand the role of kinesin-8 proteins in mitosis, we studied the effects of deletion of the fission yeast kinesin-8 proteins Klp5 and Klp6 on chromosome movements and spindle length dynamics. Aberrant microtubule-driven kinetochore pushing movements and tripolar mitotic spindles occurred in cells lacking Klp5 but not Klp6. Kinesin-8–deletion strains showed large fluctuations in metaphase spindle length, suggesting a disruption of spindle length stabilization. Comparison of our results from light microscopy with a mathematical model suggests that kinesin-8–induced effects on microtubule dynamics, kinetochore attachment stability, and sliding force in the spindle can explain the aberrant chromosome movements and spindle length fluctuations seen.
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Affiliation(s)
- Zachary R Gergely
- Department of Physics, University of Colorado at Boulder, Boulder, CO 80309.,Department of MCD Biology, University of Colorado at Boulder, Boulder, CO 80309
| | - Ammon Crapo
- Department of Physics, University of Colorado at Boulder, Boulder, CO 80309
| | - Loren E Hough
- Department of Physics, University of Colorado at Boulder, Boulder, CO 80309
| | - J Richard McIntosh
- Department of MCD Biology, University of Colorado at Boulder, Boulder, CO 80309
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41
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How the kinetochore couples microtubule force and centromere stretch to move chromosomes. Nat Cell Biol 2016; 18:382-92. [PMID: 26974660 PMCID: PMC4814359 DOI: 10.1038/ncb3323] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 02/04/2016] [Indexed: 02/07/2023]
Abstract
The Ndc80 complex (Ndc80, Nuf2, Spc24 and Spc25) is a highly conserved kinetochore protein essential for end-on anchorage to spindle microtubule plus ends and for force generation coupled to plus-end polymerization and depolymerization. Spc24/Spc25 at one end of the Ndc80 complex binds the kinetochore. The N-terminal tail and CH domains of Ndc80 bind microtubules, and an internal domain binds microtubule-associated proteins (MAPs) such as the Dam1 complex. To determine how the microtubule- and MAP-binding domains of Ndc80 contribute to force production at the kinetochore in budding yeast, we have inserted a FRET tension sensor into the Ndc80 protein about halfway between its microtubule-binding and internal loop domains. The data support a mechanical model of force generation at metaphase where the position of the kinetochore relative to the microtubule plus end reflects the relative strengths of microtubule depolymerization, centromere stretch and microtubule-binding interactions with the Ndc80 and Dam1 complexes.
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42
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Microtubule dynamics decoded by the epigenetic state of centromeric chromatin. Curr Genet 2016; 62:691-695. [PMID: 26976145 DOI: 10.1007/s00294-016-0588-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/26/2016] [Accepted: 02/29/2016] [Indexed: 12/11/2022]
Abstract
Cell division with accurate chromosome segregation is fundamental to cell survival of all organisms. The precise molecular mechanisms that ensure accurate chromosome segregation are still being discovered using a variety of experimental systems and approaches. Microtubule attachment to the kinetochore is a prerequisite for mitotic progression, failure of which activates the spindle assembly checkpoint (SAC). The dynamic tension generated by interaction of the centromere, kinetochore and microtubules is a key regulator of the SAC. Here, in the context of current literature we discuss our recent observation in fission yeast that epigenetic alterations in centromeric and pericentromeric chromatin can compensate for altered dynamics of kinetochore-microtubule attachment to permit escape from mitotic arrest. A role for the spatial configuration of the centromere to influence the finely tuned regulators of mitotic progression opens up new avenues for research.
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43
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Wilson-Kubalek EM, Cheeseman IM, Milligan RA. Structural comparison of the Caenorhabditis elegans and human Ndc80 complexes bound to microtubules reveals distinct binding behavior. Mol Biol Cell 2016; 27:1197-203. [PMID: 26941333 PMCID: PMC4831874 DOI: 10.1091/mbc.e15-12-0858] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 02/23/2016] [Indexed: 11/11/2022] Open
Abstract
During cell division, kinetochores must remain tethered to the plus ends of dynamic microtubule polymers. However, the molecular basis for robust kinetochore-microtubule interactions remains poorly understood. The conserved four-subunit Ndc80 complex plays an essential and direct role in generating dynamic kinetochore-microtubule attachments. Here we compare the binding of theCaenorhabditis elegansand human Ndc80 complexes to microtubules at high resolution using cryo-electron microscopy reconstructions. Despite the conserved roles of the Ndc80 complex in diverse organisms, we find that the attachment mode of these complexes for microtubules is distinct. The human Ndc80 complex binds every tubulin monomer along the microtubule protofilament, whereas theC. elegansNdc80 complex binds more tightly to β-tubulin. In addition, theC. elegansNdc80 complex tilts more toward the adjacent protofilament. These structural differences in the Ndc80 complex between different species may play significant roles in the nature of kinetochore-microtubule interactions.
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Affiliation(s)
- Elizabeth M Wilson-Kubalek
- Laboratory of Structure Cell Biology, Department of Integrative Structure and Computational Biology, Scripps Research Institute, La Jolla, CA 92037
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Ronald A Milligan
- Laboratory of Structure Cell Biology, Department of Integrative Structure and Computational Biology, Scripps Research Institute, La Jolla, CA 92037
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44
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Freitag M. The kinetochore interaction network (KIN) of ascomycetes. Mycologia 2016; 108:485-505. [PMID: 26908646 DOI: 10.3852/15-182] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 10/23/2015] [Indexed: 01/13/2023]
Abstract
Chromosome segregation relies on coordinated activity of a large assembly of proteins, the kinetochore interaction network (KIN). How conserved the underlying mechanisms driving the epigenetic phenomenon of centromere and kinetochore assembly and maintenance are remains unclear, even though various eukaryotic models have been studied. More than 50 different proteins, many in multiple copies, comprise the KIN or are associated with fungal centromeres and kinetochores. Proteins isolated from immune sera recognized centromeric regions on chromosomes and thus were named centromere proteins (CENPs). CENP-A, sometimes called centromere-specific H3 (CenH3), is incorporated into nucleosomes within or near centromeres. The constitutive centromere-associated network (CCAN) assembles on this specialized chromatin, likely based on specific interactions with and requiring presence of CENP-C. The outer kinetochore comprises the Knl1-Mis12-Ndc80 (KMN) protein complexes that connect CCAN to spindles, accomplished by binding and stabilizing microtubules (MTs) and in the process generating load-bearing assemblies for chromatid segregation. In most fungi the Dam1/DASH complex connects the KMN complexes to MTs. Fungi present a rich resource to investigate mechanistic commonalities but also differences in kinetochore architecture. While ascomycetes have sets of CCAN and KMN proteins that are conserved with those of budding yeast or metazoans, searching other major branches of the fungal kingdom revealed that CCAN proteins are poorly conserved at the primary sequence level. Several conserved binding motifs or domains within KMN complexes have been described recently, and these features of ascomycete KIN proteins are shared with most metazoan proteins. In addition, several ascomycete-specific domains have been identified here.
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Affiliation(s)
- Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331-7305
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45
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Escape from Mitotic Arrest: An Unexpected Connection Between Microtubule Dynamics and Epigenetic Regulation of Centromeric Chromatin in Schizosaccharomyces pombe. Genetics 2015; 201:1467-78. [PMID: 26510788 DOI: 10.1534/genetics.115.181792] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/23/2015] [Indexed: 01/02/2023] Open
Abstract
Accurate chromosome segregation is necessary to ensure genomic integrity. Segregation depends on the proper functioning of the centromere, kinetochore, and mitotic spindle microtubules and is monitored by the spindle assembly checkpoint (SAC). In the fission yeast Schizosaccharomyces pombe, defects in Dis1, a microtubule-associated protein that influences microtubule dynamics, lead to mitotic arrest as a result of an active SAC and consequent failure to grow at low temperature. In a mutant dis1 background (dis1-288), loss of function of Msc1, a fission yeast homolog of the KDM5 family of proteins, suppresses the growth defect and promotes normal mitosis. Genetic analysis implicates a histone deacetylase (HDAC)-linked pathway in suppression because HDAC mutants clr6-1, clr3∆, and sir2∆, though not hos2∆, also promote normal mitosis in the dis1-288 mutant. Suppression of the dis phenotype through loss of msc1 function requires the spindle checkpoint protein Mad2 and is limited by the presence of the heterochromatin-associated HP1 protein homolog Swi6. We speculate that alterations in histone acetylation promote a centromeric chromatin environment that compensates for compromised dis1 function by allowing for successful kinetochore-microtubule interactions that can satisfy the SAC. In cells arrested in mitosis by mutation of dis1, loss of function of epigenetic determinants such as Msc1 or specific HDACs can promote cell survival. Because the KDM5 family of proteins has been implicated in human cancers, an appreciation of the potential role of this family of proteins in chromosome segregation is warranted.
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46
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Kakui Y, Sato M. Differentiating the roles of microtubule-associated proteins at meiotic kinetochores during chromosome segregation. Chromosoma 2015; 125:309-20. [PMID: 26383111 DOI: 10.1007/s00412-015-0541-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 09/06/2015] [Accepted: 09/08/2015] [Indexed: 11/30/2022]
Abstract
Meiosis is a specialised cell division process for generating gametes. In contrast to mitosis, meiosis involves recombination followed by two consecutive rounds of cell division, meiosis I and II. A vast field of research has been devoted to understanding the differences between mitotic and meiotic cell divisions from the viewpoint of chromosome behaviour. For faithful inheritance of paternal and maternal genetic information to offspring, two events are indispensable: meiotic recombination, which generates a physical link between homologous chromosomes, and reductional segregation, in which homologous chromosomes move towards opposite poles, thereby halving the ploidy. The cytoskeleton and its regulators play specialised roles in meiosis to accomplish these divisions. Recent studies have shown that microtubule-associated proteins (MAPs), including tumour overexpressed gene (TOG), play unique roles during meiosis. Furthermore, the conserved mitotic protein kinase Polo modulates MAP localisation in meiosis I. As Polo is a well-known regulator of reductional segregation in meiosis, the evidence suggests that Polo constitutes a plausible link between meiosis-specific MAP functions and reductional segregation. Here, we review the latest findings on how the localisation and regulation of MAPs in meiosis differ from those in mitosis, and we discuss conservation of the system between yeast and higher eukaryotes.
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Affiliation(s)
- Yasutaka Kakui
- Chromosome Segregation Laboratory, The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK.
| | - Masamitsu Sato
- Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku, Tokyo, 162-0056, Japan.
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47
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Aravamudhan P, Goldfarb AA, Joglekar AP. The kinetochore encodes a mechanical switch to disrupt spindle assembly checkpoint signalling. Nat Cell Biol 2015; 17:868-79. [PMID: 26053220 PMCID: PMC4630029 DOI: 10.1038/ncb3179] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 04/23/2015] [Indexed: 12/14/2022]
Abstract
The spindle assembly checkpoint (SAC) is a unique signalling mechanism that responds to the state of attachment of the kinetochore to spindle microtubules. SAC signalling is activated by unattached kinetochores, and it is silenced after these kinetochores form end-on microtubule attachments. Although the biochemical cascade of SAC signalling is well understood, how kinetochore-microtubule attachment disrupts it remained unknown. Here we show that, in budding yeast, end-on microtubule attachment to the kinetochore physically separates the Mps1 kinase, which probably binds to the calponin homology domain of Ndc80, from the kinetochore substrate of Mps1, Spc105 (KNL1 orthologue). This attachment-mediated separation disrupts the phosphorylation of Spc105, and enables SAC silencing. Additionally, the Dam1 complex may act as a barrier that shields Spc105 from Mps1. Together these data suggest that the protein architecture of the kinetochore encodes a mechanical switch. End-on microtubule attachment to the kinetochore turns this switch off to silence the SAC.
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Affiliation(s)
| | - Alan A. Goldfarb
- Cell and developmental biology, University of Michigan, 109 Zina Pitcher Place, 3067 BSRB, Ann Arbor, MI-48109, USA
| | - Ajit P. Joglekar
- Biophysics, University of Michigan, Ann Arbor, MI-48109, USA
- Cell and developmental biology, University of Michigan, 109 Zina Pitcher Place, 3067 BSRB, Ann Arbor, MI-48109, USA
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48
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Connecting the microtubule attachment status of each kinetochore to cell cycle arrest through the spindle assembly checkpoint. Chromosoma 2015; 124:463-80. [PMID: 25917595 DOI: 10.1007/s00412-015-0515-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/01/2015] [Accepted: 04/02/2015] [Indexed: 12/12/2022]
Abstract
Kinetochores generate a signal that inhibits anaphase progression until every kinetochore makes proper attachments to spindle microtubules. This spindle assembly checkpoint (SAC) increases the fidelity of chromosome segregation. We will review the molecular mechanisms by which kinetochores generate the SAC and extinguish the signal after making proper attachments, with the goal of identifying unanswered questions and new research directions. We will emphasize recent breakthroughs in how phosphorylation changes drive the activation and inhibition of the signal. We will also emphasize the dramatic changes in kinetochore structure that occur after attaching to microtubules and how these coordinate SAC function with microtubule attachment status. Finally, we will review the emerging cross talk between the DNA damage response and the SAC.
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49
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Nilsson J. Can sequestering of mitotic spindle proteins cause aneuploidy? (Comment on DOI 10.1002/bies.201400175). Bioessays 2015; 37:234. [PMID: 25640704 DOI: 10.1002/bies.201400210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jakob Nilsson
- The Novo Nordisk Foundation - Center for Protein Research, University of Copenhagen, Faculty of Health and Medical Sciences, Copenhagen, Denmark
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50
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Tamura N, Simon JE, Nayak A, Shenoy RT, Hiroi N, Boilot V, Funahashi A, Draviam VM. A proteomic study of mitotic phase-specific interactors of EB1 reveals a role for SXIP-mediated protein interactions in anaphase onset. Biol Open 2015; 4:155-69. [PMID: 25596275 PMCID: PMC4365484 DOI: 10.1242/bio.201410413] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/07/2014] [Indexed: 12/12/2022] Open
Abstract
Microtubules execute diverse mitotic events that are spatially and temporally separated; the underlying regulation is poorly understood. By combining drug treatments, large-scale immunoprecipitation and mass spectrometry, we report the first comprehensive map of mitotic phase-specific protein interactions of the microtubule-end binding protein, EB1. EB1 interacts with some, but not all, of its partners throughout mitosis. We show that the interaction of EB1 with Astrin-SKAP complex, a key regulator of chromosome segregation, is enhanced during prometaphase, compared to anaphase. We find that EB1 and EB3, another EB family member, can interact directly with SKAP, in an SXIP-motif dependent manner. Using an SXIP defective mutant that cannot interact with EB, we uncover two distinct pools of SKAP at spindle microtubules and kinetochores. We demonstrate the importance of SKAP's SXIP-motif in controlling microtubule growth rates and anaphase onset, without grossly disrupting spindle function. Thus, we provide the first comprehensive map of temporal changes in EB1 interactors during mitosis and highlight the importance of EB protein interactions in ensuring normal mitosis.
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Affiliation(s)
- Naoka Tamura
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Judith E Simon
- Department of Genetics, University of Cambridge, Cambridge, UK Present address: European Research Institute for the Biology of Ageing, University of Groningen, Groningen, Netherlands
| | - Arnab Nayak
- Department of Genetics, University of Cambridge, Cambridge, UK Present address: Institute for Biochemistry II, Goethe University Frankfurt am Main, Germany
| | - Rajesh T Shenoy
- Department of Genetics, University of Cambridge, Cambridge, UK
| | | | - Viviane Boilot
- Department of Genetics, University of Cambridge, Cambridge, UK
| | | | - Viji M Draviam
- Department of Genetics, University of Cambridge, Cambridge, UK
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