1
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Li Q, Chen Q, Zheng T, Wang F, Teng J, Zhou H, Chen J. CCDC68 Maintains Mitotic Checkpoint Activation by Promoting CDC20 Integration into the MCC. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2406009. [PMID: 39018254 DOI: 10.1002/advs.202406009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Indexed: 07/19/2024]
Abstract
The spindle assembly checkpoint (SAC) ensures chromosome segregation fidelity by manipulating unattached kinetochore-dependent assembly of the mitotic checkpoint complex (MCC). The MCC binds to and inhibits the anaphase promoting complex/cyclosome (APC/C) to postpone mitotic exit. However, the mechanism by which unattached kinetochores mediate MCC formation is not yet fully understood. Here, it is shown that CCDC68 is an outer kinetochore protein that preferentially localizes to unattached kinetochores. Furthermore, CCDC68 interacts with the SAC factor CDC20 to inhibit its autoubiquitination and MCC disassembly. Therefore, CCDC68 restrains APC/C activation to ensure a robust SAC and allow sufficient time for chromosome alignment, thus ensuring chromosomal stability. Hence, the study reveals that CCDC68 is required for CDC20-dependent MCC stabilization to maintain mitotic checkpoint activation.
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Affiliation(s)
- Qi Li
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Qingzhou Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Tao Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Fulin Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Junlin Teng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Haining Zhou
- Key Laboratory of Epigenetic Regulation and Intervention, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jianguo Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, 100871, China
- Center for Quantitative Biology, Peking University, Beijing, 100871, China
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2
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Houston J, Vissotsky C, Deep A, Hakozaki H, Crews E, Oegema K, Corbett KD, Lara-Gonzalez P, Kim T, Desai A. Phospho-KNL-1 recognition by a TPR domain targets the BUB-1-BUB-3 complex to C. elegans kinetochores. J Cell Biol 2024; 223:e202402036. [PMID: 38578284 PMCID: PMC10996584 DOI: 10.1083/jcb.202402036] [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: 02/05/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/06/2024] Open
Abstract
During mitosis, the Bub1-Bub3 complex concentrates at kinetochores, the microtubule-coupling interfaces on chromosomes, where it contributes to spindle checkpoint activation, kinetochore-spindle microtubule interactions, and protection of centromeric cohesion. Bub1 has a conserved N-terminal tetratricopeptide repeat (TPR) domain followed by a binding motif for its conserved interactor Bub3. The current model for Bub1-Bub3 localization to kinetochores is that Bub3, along with its bound motif from Bub1, recognizes phosphorylated "MELT" motifs in the kinetochore scaffold protein Knl1. Motivated by the greater phenotypic severity of BUB-1 versus BUB-3 loss in C. elegans, we show that the BUB-1 TPR domain directly recognizes a distinct class of phosphorylated motifs in KNL-1 and that this interaction is essential for BUB-1-BUB-3 localization and function. BUB-3 recognition of phospho-MELT motifs additively contributes to drive super-stoichiometric accumulation of BUB-1-BUB-3 on its KNL-1 scaffold during mitotic entry. Bub1's TPR domain interacts with Knl1 in other species, suggesting that collaboration of TPR-dependent and Bub3-dependent interfaces in Bub1-Bub3 localization and functions may be conserved.
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Affiliation(s)
- Jack Houston
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | | | - Amar Deep
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Hiroyuki Hakozaki
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Enice Crews
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Karen Oegema
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Kevin D. Corbett
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Taekyung Kim
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Department of Biology Education, Pusan National University, Busan, Republic of Korea
| | - Arshad Desai
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
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3
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Hoellerbauer P, Kufeld M, Arora S, Mitchell K, Girard E, Herman J, Olson J, Paddison P. FBXO42 activity is required to prevent mitotic arrest, spindle assembly checkpoint activation and lethality in glioblastoma and other cancers. NAR Cancer 2024; 6:zcae021. [PMID: 38774470 PMCID: PMC11106029 DOI: 10.1093/narcan/zcae021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/23/2024] [Accepted: 05/15/2024] [Indexed: 05/24/2024] Open
Abstract
Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. To identify genes differentially required for the viability of GBM stem-like cells (GSCs), we performed functional genomic lethality screens comparing GSCs and control human neural stem cells. Among top-scoring hits in a subset of GBM cells was the F-box-containing gene FBXO42, which was also predicted to be essential in ∼15% of cell lines derived from a broad range of cancers. Mechanistic studies revealed that, in sensitive cells, FBXO42 activity prevents chromosome alignment defects, mitotic cell cycle arrest and cell death. The cell cycle arrest, but not the cell death, triggered by FBXO42 inactivation could be suppressed by brief exposure to a chemical inhibitor of Mps1, a key spindle assembly checkpoint (SAC) kinase. FBXO42's cancer-essential function requires its F-box and Kelch domains, which are necessary for FBXO42's substrate recognition and targeting by SCF (SKP1-CUL1-F-box protein) ubiquitin ligase complex. However, none of FBXO42's previously proposed targets, including ING4, p53 and RBPJ, were responsible for the observed phenotypes. Instead, our results suggest that FBOX42 alters the activity of one or more proteins that perturb chromosome-microtubule dynamics in cancer cells, which in turn leads to induction of the SAC and cell death.
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Affiliation(s)
- Pia Hoellerbauer
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, 98109 USA
| | - Megan Kufeld
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
| | - Sonali Arora
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
| | - Kelly Mitchell
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
| | - Emily J Girard
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
- Ben Towne Center for Childhood Cancer Research, Seattle Children’s Research Institute, Seattle, WA, 98101 USA
| | - Jacob A Herman
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
| | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
- Ben Towne Center for Childhood Cancer Research, Seattle Children’s Research Institute, Seattle, WA, 98101 USA
| | - Patrick J Paddison
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, 98109 USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, 98109 USA
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4
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Ouzounidis VR, Green M, van Capelle CDC, Gebhardt C, Crellin H, Finlayson C, Prevo B, Cheerambathur DK. The outer kinetochore components KNL-1 and Ndc80 complex regulate axon and neuronal cell body positioning in the C. elegans nervous system. Mol Biol Cell 2024; 35:ar83. [PMID: 38656792 PMCID: PMC11238089 DOI: 10.1091/mbc.e23-08-0325] [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: 08/23/2023] [Revised: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
The KMN (Knl1/Mis12/Ndc80) network at the kinetochore, primarily known for its role in chromosome segregation, has been shown to be repurposed during neurodevelopment. Here, we investigate the underlying neuronal mechanism and show that the KMN network promotes the proper axonal organization within the C. elegans head nervous system. Postmitotic degradation of KNL-1, which acts as a scaffold for signaling and has microtubule-binding activities at the kinetochore, led to disorganized ganglia and aberrant placement and organization of axons in the nerve ring - an interconnected axonal network. Through gene-replacement approaches, we demonstrate that the signaling motifs within KNL-1, responsible for recruiting protein phosphatase 1, and activating the spindle assembly checkpoint are required for neurodevelopment. Interestingly, while the microtubule-binding activity is crucial to KMN's neuronal function, microtubule dynamics and organization were unaffected in the absence of KNL-1. Instead, the NDC-80 microtubule-binding mutant displayed notable defects in axon bundling during nerve ring formation, indicating its role in facilitating axon-axon contacts. Overall, these findings provide evidence for a noncanonical role for the KMN network in shaping the structure and connectivity of the nervous system in C. elegans during brain development.
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Affiliation(s)
- Vasileios R. Ouzounidis
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Mattie Green
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Charlotte de Ceuninck van Capelle
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Clara Gebhardt
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Helena Crellin
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Cameron Finlayson
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Bram Prevo
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Dhanya K. Cheerambathur
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
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5
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Kim S, Lau TT, Liao MK, Ma HT, Poon RY. Coregulation of NDC80 Complex Subunits Determines the Fidelity of the Spindle-Assembly Checkpoint and Mitosis. Mol Cancer Res 2024; 22:423-439. [PMID: 38324016 PMCID: PMC11063766 DOI: 10.1158/1541-7786.mcr-23-0828] [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: 10/10/2023] [Revised: 12/07/2023] [Accepted: 02/05/2024] [Indexed: 02/08/2024]
Abstract
NDC80 complex (NDC80C) is composed of four subunits (SPC24, SPC25, NDC80, and NUF2) and is vital for kinetochore-microtubule (KT-MT) attachment during mitosis. Paradoxically, NDC80C also functions in the activation of the spindle-assembly checkpoint (SAC). This raises an interesting question regarding how mitosis is regulated when NDC80C levels are compromised. Using a degron-mediated depletion system, we found that acute silencing of SPC24 triggered a transient mitotic arrest followed by mitotic slippage. SPC24-deficient cells were unable to sustain SAC activation despite the loss of KT-MT interaction. Intriguingly, our results revealed that other subunits of the NDC80C were co-downregulated with SPC24 at a posttranslational level. Silencing any individual subunit of NDC80C likewise reduced the expression of the entire complex. We found that the SPC24-SPC25 and NDC80-NUF2 subcomplexes could be individually stabilized using ectopically expressed subunits. The synergism of SPC24 downregulation with drugs that promote either mitotic arrest or mitotic slippage further underscored the dual roles of NDC80C in KT-MT interaction and SAC maintenance. The tight coordinated regulation of NDC80C subunits suggests that targeting individual subunits could disrupt mitotic progression and provide new avenues for therapeutic intervention. IMPLICATIONS These results highlight the tight coordinated regulation of NDC80C subunits and their potential as targets for antimitotic therapies.
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Affiliation(s)
- Sehong Kim
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Thomas T.Y. Lau
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Man Kit Liao
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Hoi Tang Ma
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Randy Y.C. Poon
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
- State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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6
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Chen SY, Cheng PW, Peng HF, Wu JC. C. elegans spermatocyte divisions show a weak spindle checkpoint response. J Cell Sci 2024; 137:jcs257675. [PMID: 38372383 DOI: 10.1242/jcs.257675] [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: 11/30/2020] [Accepted: 02/13/2024] [Indexed: 02/20/2024] Open
Abstract
Male meiotic division exhibits two consecutive chromosome separation events without apparent pausing. Several studies have shown that spermatocyte divisions are not stringently regulated as in mitotic cells. In this study, we investigated the role of the canonical spindle assembly (SAC) pathway in Caenorhabditis elegans spermatogenesis. We found the intensity of chromosome-associated outer kinetochore protein BUB-1 and SAC effector MDF-1 oscillates between the two divisions. However, the SAC target securin is degraded during the first division and remains undetectable for the second division. Inhibition of proteasome-dependent protein degradation did not affect the progression of the second division but stopped the first division at metaphase. Perturbation of spindle integrity did not affect the duration of meiosis II, and only slightly lengthened meiosis I. Our results demonstrate that male meiosis II is independent of SAC regulation, and male meiosis I exhibits only weak checkpoint response.
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Affiliation(s)
- Shang-Yang Chen
- Department of Clinical Laboratory Science and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei 10048, Taiwan
| | - Pu-Wei Cheng
- Department of Clinical Laboratory Science and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei 10048, Taiwan
| | - Hsiao-Fang Peng
- Department of Clinical Laboratory Science and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei 10048, Taiwan
| | - Jui-Ching Wu
- Department of Clinical Laboratory Science and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei 10048, Taiwan
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei 10048, Taiwan
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7
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Houston J, Vissotsky C, Deep A, Hakozaki H, Crews E, Oegema K, Corbett KD, Lara-Gonzalez P, Kim T, Desai A. Phospho-KNL-1 recognition by a TPR domain targets the BUB-1-BUB-3 complex to C. elegans kinetochores. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579536. [PMID: 38370671 PMCID: PMC10871365 DOI: 10.1101/2024.02.09.579536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
During mitosis, the Bub1-Bub3 complex concentrates at kinetochores, the microtubule-coupling interfaces on chromosomes, where it contributes to spindle checkpoint activation, kinetochore-spindle microtubule interactions, and protection of centromeric cohesion. Bub1 has a conserved N-terminal tetratricopeptide (TPR) domain followed by a binding motif for its conserved interactor Bub3. The current model for Bub1-Bub3 localization to kinetochores is that Bub3, along with its bound motif from Bub1, recognizes phosphorylated "MELT" motifs in the kinetochore scaffold protein Knl1. Motivated by the greater phenotypic severity of BUB-1 versus BUB-3 loss in C. elegans, we show that the BUB-1 TPR domain directly recognizes a distinct class of phosphorylated motifs in KNL-1 and that this interaction is essential for BUB-1-BUB-3 localization and function. BUB-3 recognition of phospho-MELT motifs additively contributes to drive super-stoichiometric accumulation of BUB-1-BUB-3 on its KNL-1 scaffold during mitotic entry. Bub1's TPR domain interacts with Knl1 in other species, suggesting that collaboration of TPR-dependent and Bub3-dependent interfaces in Bub1-Bub3 localization and functions may be conserved.
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Affiliation(s)
- Jack Houston
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093, USA
- Department of Cell & Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
- Ludwig Institute for Cancer Research, La Jolla, California 92093, USA
| | | | - Amar Deep
- Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Hiro Hakozaki
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Enice Crews
- Department of Cell & Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - Karen Oegema
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093, USA
- Department of Cell & Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
- Ludwig Institute for Cancer Research, La Jolla, California 92093, USA
- Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Kevin D. Corbett
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093, USA
- Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, La Jolla, California 92093, USA
- Department of Developmental & Cell Biology, University of California Irvine, Irvine, CA 92697, USA
| | - Taekyung Kim
- Ludwig Institute for Cancer Research, La Jolla, California 92093, USA
- Department of Biology Education, Pusan National University, Busan 46241, Republic of Korea
| | - Arshad Desai
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093, USA
- Department of Cell & Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
- Ludwig Institute for Cancer Research, La Jolla, California 92093, USA
- Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
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8
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Zimyanin V, Magaj M, Yu CH, Gibney T, Mustafa B, Horton X, Siller K, Cueff L, Bouvrais H, Pécréaux J, Needleman D, Redemann S. Lack of chromokinesin Klp-19 creates a more rigid midzone and affects force transmission during anaphase in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.564275. [PMID: 37961478 PMCID: PMC10634869 DOI: 10.1101/2023.10.26.564275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Recent studies have highlighted the significance of the spindle midzone - the region positioned between chromosomes - in ensuring proper chromosome segregation. By combining advanced 3D electron tomography and cutting-edge light microscopy we have discovered a previously unknown role of the regulation of microtubule dynamics within the spindle midzone of C. elegans. Using Fluorescence recovery after photobleaching and a combination of second harmonic generation and two-photon fluorescence microscopy, we found that the length of the antiparallel microtubule overlap zone in the spindle midzone is constant throughout anaphase, and independent of cortical pulling forces as well as the presence of the microtubule bundling protein SPD-1. Further investigations of SPD-1 and the chromokinesin KLP-19 in C. elegans suggest that KLP-19 regulates the overlap length and functions independently of SPD-1. Our data shows that KLP-19 plays an active role in regulating the length and turn-over of microtubules within the midzone as well as the size of the antiparallel overlap region throughout mitosis. Depletion of KLP-19 in mitosis leads to an increase in microtubule length in the spindle midzone, which also leads to increased microtubule - microtubule interaction, thus building up a more robust microtubule network. The spindle is globally stiffer and more stable, which has implications for the transmission of forces within the spindle affecting chromosome segregation dynamics. Our data shows that by localizing KLP-19 to the spindle midzone in anaphase microtubule dynamics can be locally controlled allowing the formation of a functional midzone.
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Affiliation(s)
- Vitaly Zimyanin
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Magdalena Magaj
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Che-Hang Yu
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, USA
| | - Theresa Gibney
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Basaran Mustafa
- Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xavier Horton
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Karsten Siller
- IT-Research Computing, University of Virginia, Charlottesville, VA, USA
| | - Louis Cueff
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Hélène Bouvrais
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Jacques Pécréaux
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Daniel Needleman
- Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
| | - Stefanie Redemann
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
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9
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Pitayu-Nugroho L, Aubry M, Laband K, Geoffroy H, Ganeswaran T, Primadhanty A, Canman JC, Dumont J. Kinetochore component function in C. elegans oocytes revealed by 4D tracking of holocentric chromosomes. Nat Commun 2023; 14:4032. [PMID: 37419936 PMCID: PMC10329006 DOI: 10.1038/s41467-023-39702-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 06/19/2023] [Indexed: 07/09/2023] Open
Abstract
During cell division, chromosome congression to the spindle center, their orientation along the spindle long axis and alignment at the metaphase plate depend on interactions between spindle microtubules and kinetochores, and are pre-requisite for chromosome bi-orientation and accurate segregation. How these successive phases are controlled during oocyte meiosis remains elusive. Here we provide 4D live imaging during the first meiotic division in C. elegans oocytes with wild-type or disrupted kinetochore protein function. We show that, unlike in monocentric organisms, holocentric chromosome bi-orientation is not strictly required for accurate chromosome segregation. Instead, we propose a model in which initial kinetochore-localized BHC module (comprised of BUB-1Bub1, HCP-1/2CENP-F and CLS-2CLASP)-dependent pushing acts redundantly with Ndc80 complex-mediated pulling for accurate chromosome segregation in meiosis. In absence of both mechanisms, homologous chromosomes tend to co-segregate in anaphase, especially when initially mis-oriented. Our results highlight how different kinetochore components cooperate to promote accurate holocentric chromosome segregation in oocytes of C. elegans.
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Affiliation(s)
| | - Mélanie Aubry
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Kimberley Laband
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Hélène Geoffroy
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | | | | | - Julie C Canman
- Columbia University Irving Medical Center; Department of Pathology and Cell Biology, New York, NY, 10032, USA
| | - Julien Dumont
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France.
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10
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Houston J, Ohta M, Gómez-Cavazos JS, Deep A, Corbett KD, Oegema K, Lara-Gonzalez P, Kim T, Desai A. BUB-1-bound PLK-1 directs CDC-20 kinetochore recruitment to ensure timely embryonic mitoses. Curr Biol 2023; 33:2291-2299.e10. [PMID: 37137308 PMCID: PMC10270731 DOI: 10.1016/j.cub.2023.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 03/13/2023] [Accepted: 04/12/2023] [Indexed: 05/05/2023]
Abstract
During mitosis, chromosomes assemble kinetochores to dynamically couple with spindle microtubules.1,2 Kinetochores also function as signaling hubs directing mitotic progression by recruiting and controlling the fate of the anaphase promoting complex/cyclosome (APC/C) activator CDC-20.3,4,5 Kinetochores either incorporate CDC-20 into checkpoint complexes that inhibit the APC/C or dephosphorylate CDC-20, which allows it to interact with and activate the APC/C.4,6 The importance of these two CDC-20 fates likely depends on the biological context. In human somatic cells, the major mechanism controlling mitotic progression is the spindle checkpoint. By contrast, progression through mitosis during the cell cycles of early embryos is largely checkpoint independent.7,8,9,10 Here, we first show that CDC-20 phosphoregulation controls mitotic duration in the C. elegans embryo and defines a checkpoint-independent temporal mitotic optimum for robust embryogenesis. CDC-20 phosphoregulation occurs at kinetochores and in the cytosol. At kinetochores, the flux of CDC-20 for local dephosphorylation requires an ABBA motif on BUB-1 that directly interfaces with the structured WD40 domain of CDC-20.6,11,12,13 We next show that a conserved "STP" motif in BUB-1 that docks the mitotic kinase PLK-114 is necessary for CDC-20 kinetochore recruitment and timely mitotic progression. The kinase activity of PLK-1 is required for CDC-20 to localize to kinetochores and phosphorylates the CDC-20-binding ABBA motif of BUB-1 to promote BUB-1-CDC-20 interaction and mitotic progression. Thus, the BUB-1-bound pool of PLK-1 ensures timely mitosis during embryonic cell cycles by promoting CDC-20 recruitment to the vicinity of kinetochore-localized phosphatase activity.
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Affiliation(s)
- Jack Houston
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA
| | - Midori Ohta
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA
| | - J Sebastián Gómez-Cavazos
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cell and Developmental Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Amar Deep
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kevin D Corbett
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karen Oegema
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA; Department of Cell and Developmental Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Pablo Lara-Gonzalez
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA; Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Taekyung Kim
- Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA; Department of Biology Education, Pusan National University, Busan 46241, Republic of Korea.
| | - Arshad Desai
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA; Department of Cell and Developmental Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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11
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Macaisne N, Bellutti L, Laband K, Edwards F, Pitayu-Nugroho L, Gervais A, Ganeswaran T, Geoffroy H, Maton G, Canman JC, Lacroix B, Dumont J. Synergistic stabilization of microtubules by BUB-1, HCP-1, and CLS-2 controls microtubule pausing and meiotic spindle assembly. eLife 2023; 12:e82579. [PMID: 36799894 PMCID: PMC10005782 DOI: 10.7554/elife.82579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 02/16/2023] [Indexed: 02/18/2023] Open
Abstract
During cell division, chromosome segregation is orchestrated by a microtubule-based spindle. Interaction between spindle microtubules and kinetochores is central to the bi-orientation of chromosomes. Initially dynamic to allow spindle assembly and kinetochore attachments, which is essential for chromosome alignment, microtubules are eventually stabilized for efficient segregation of sister chromatids and homologous chromosomes during mitosis and meiosis I, respectively. Therefore, the precise control of microtubule dynamics is of utmost importance during mitosis and meiosis. Here, we study the assembly and role of a kinetochore module, comprised of the kinase BUB-1, the two redundant CENP-F orthologs HCP-1/2, and the CLASP family member CLS-2 (hereafter termed the BHC module), in the control of microtubule dynamics in Caenorhabditis elegans oocytes. Using a combination of in vivo structure-function analyses of BHC components and in vitro microtubule-based assays, we show that BHC components stabilize microtubules, which is essential for meiotic spindle formation and accurate chromosome segregation. Overall, our results show that BUB-1 and HCP-1/2 do not only act as targeting components for CLS-2 at kinetochores, but also synergistically control kinetochore-microtubule dynamics by promoting microtubule pause. Together, our results suggest that BUB-1 and HCP-1/2 actively participate in the control of kinetochore-microtubule dynamics in the context of an intact BHC module to promote spindle assembly and accurate chromosome segregation in meiosis.
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Affiliation(s)
- Nicolas Macaisne
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
| | - Laura Bellutti
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
| | - Kimberley Laband
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
| | - Frances Edwards
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
| | | | - Alison Gervais
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
| | | | - Hélène Geoffroy
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
| | - Gilliane Maton
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
| | - Julie C Canman
- Columbia University; Department of Pathology and Cell BiologyNew YorkUnited States
| | - Benjamin Lacroix
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), CNRS UMR 5237, Université de MontpellierMontpellierFrance
| | - Julien Dumont
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013ParisFrance
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12
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Fischer ES. Kinetochore‐catalyzed MCC
formation: A structural perspective. IUBMB Life 2022; 75:289-310. [PMID: 36518060 DOI: 10.1002/iub.2697] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/08/2022] [Indexed: 12/23/2022]
Abstract
The spindle assembly checkpoint (SAC) is a cellular surveillance mechanism that functions to ensure accurate chromosome segregation during mitosis. Macromolecular complexes known as kinetochores, act as the interface of sister chromatid attachment to spindle microtubules. In response to unattached kinetochores, the SAC activates its effector, the mitotic checkpoint complex (MCC), which delays mitotic exit until all sister chromatid pairs have achieved successful attachment to the bipolar mitotic spindle. Formation of the MCC (composed of Mad2, BubR1, Bub3 and Cdc20) is regulated by an Mps1 kinase-dependent phosphorylation signaling cascade which assembles and repositions components of the MCC onto a catalytic scaffold. This scaffold functions to catalyze the conversion of the HORMA-domain protein Mad2 from an "inactive" open-state (O-Mad2) into an "active" closed-Mad2 (C-Mad2), and simultaneous Cdc20 binding. Here, our current understanding of the molecular mechanisms underlying the kinetic barrier to C-Mad2:Cdc20 formation will be reviewed. Recent progress in elucidating the precise molecular choreography orchestrated by the catalytic scaffold to rapidly assemble the MCC will be examined, and unresolved questions will be highlighted. Ultimately, understanding how the SAC rapidly activates the checkpoint not only provides insights into how cells maintain genomic integrity during mitosis, but also provides a paradigm for how cells can utilize molecular switches, including other HORMA domain-containing proteins, to make rapid changes to a cell's physiological state.
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Affiliation(s)
- Elyse S. Fischer
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus Cambridge UK
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13
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Elowe S, Bolanos-Garcia VM. The spindle checkpoint proteins BUB1 and BUBR1: (SLiM)ming down to the basics. Trends Biochem Sci 2022; 47:352-366. [DOI: 10.1016/j.tibs.2022.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/16/2022]
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14
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Gu Y, Desai A, Corbett KD. Evolutionary Dynamics and Molecular Mechanisms of HORMA Domain Protein Signaling. Annu Rev Biochem 2022; 91:541-569. [PMID: 35041460 DOI: 10.1146/annurev-biochem-090920-103246] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Controlled assembly and disassembly of multi-protein complexes is central to cellular signaling. Proteins of the widespread and functionally diverse HORMA family nucleate assembly of signaling complexes by binding short peptide motifs through a distinctive safety-belt mechanism. HORMA proteins are now understood as key signaling proteins across kingdoms, serving as infection sensors in a bacterial immune system and playing central roles in eukaryotic cell cycle, genome stability, sexual reproduction, and cellular homeostasis pathways. Here, we describe how HORMA proteins' unique ability to adopt multiple conformational states underlies their functions in these diverse contexts. We also outline how a dedicated AAA+ ATPase regulator, Pch2/TRIP13, manipulates HORMA proteins' conformational states to activate or inactivate signaling in different cellular contexts. The emergence of Pch2/TRIP13 as a lynchpin for HORMA protein action in multiple genome-maintenance pathways accounts for its frequent misregulation in human cancers and highlights TRIP13 as a novel therapeutic target. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Yajie Gu
- Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, California, USA;
| | - Arshad Desai
- Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, California, USA; .,Section of Cell & Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, California, USA.,Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, California, USA
| | - Kevin D Corbett
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
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15
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Mad1's ability to interact with Mad2 is essential to regulate and monitor meiotic synapsis in C. elegans. PLoS Genet 2021; 17:e1009598. [PMID: 34762652 PMCID: PMC8610272 DOI: 10.1371/journal.pgen.1009598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 11/23/2021] [Accepted: 10/11/2021] [Indexed: 11/19/2022] Open
Abstract
Meiotic homolog synapsis is essential to ensure accurate segregation of chromosomes during meiosis. In C. elegans, proper regulation of synapsis and a checkpoint that monitors synapsis relies on the spindle checkpoint components, Mad1 and Mad2, and Pairing Centers (PCs), cis-acting loci that interact with the nuclear envelope to mobilize chromosomes within the nucleus. Here, we test what specific functions of Mad1 and Mad2 are required to regulate and monitor synapsis. We find that a mutation that prevents Mad1's localization to the nuclear periphery abolishes the synapsis checkpoint but has no effect on Mad2's localization to the nuclear periphery or synapsis. By contrast, a mutation that prevents Mad1's interaction with Mad2 abolishes the synapsis checkpoint, delays synapsis and fails to localize Mad2 to the nuclear periphery. These data indicate that Mad1's primary role in regulating synapsis is through control of Mad2 and that Mad2 can bind other factors at the nuclear periphery. We also tested whether Mad2's ability to adopt a specific conformation associated with its activity during spindle checkpoint function is required for its role in meiosis. A mutation that prevents Mad2 from adopting its active conformer fails to localize to the nuclear periphery, abolishes the synapsis checkpoint and exhibits substantial defects in meiotic synapsis. Thus, Mad2, and its regulation by Mad1, is an important regulator of meiotic synapsis in C. elegans.
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16
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Madloo P, Lema M, Cartea ME, Soengas P. Sclerotinia sclerotiorum Response to Long Exposure to Glucosinolate Hydrolysis Products by Transcriptomic Approach. Microbiol Spectr 2021; 9:e0018021. [PMID: 34259546 PMCID: PMC8552769 DOI: 10.1128/spectrum.00180-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 05/24/2021] [Indexed: 11/21/2022] Open
Abstract
White mold disease, caused by the necrotrophic fungus Sclerotinia sclerotiorum, affects Brassica crops. Brassica crops produce a broad array of compounds, such as glucosinolates, which contribute to the defense against pathogens. From their hydrolysis, several products arise that have antimicrobial activity (GHPs) whose toxicity is structure dependent. S. sclerotiorum may overcome the toxic effect of moderate GHP concentrations after prolonged exposure to their action. Our objective was to identify the molecular mechanism underlying S. sclerotiorum response to long exposure to two chemically diverse GHPs: aliphatic GHP allyl-isothiocyanate (AITC) and indole GHP indol-3-carbinol (I3C). We found that the transcriptomic response is dependent on the type of GHP and on their initial target, involving cell membranes in the case of AITC or DNA in the case of I3C. Response mechanisms include the reorganization of chromatin, mediated by histone chaperones hip4 and cia1, ribosome synthesis controlled by the kinase-phosphatase pair aps1-ppn1, catabolism of proteins, ergosterol synthesis, and induction of detoxification systems. These mechanisms probably help S. sclerotiorum to grow and survive in an environment where GHPs are constantly produced by Brassica plants upon glucosinolate breakdown. IMPORTANCEBrassica species, including important vegetable crops, such as cabbage, cauliflower, or broccoli, or oil crops, such as rapeseed, produce specific chemical compounds useful to protect them against pests and pathogens. One of the most destructive Brassica diseases in temperate areas around the world is Sclerotinia stem rot, caused by the fungus Sclerotinia sclerotiorum. This is a generalist pathogen that causes disease over more than 400 plant species, being a serious threat to economically important crops worldwide, including potato, bean, soybean, and sunflower, among many others. Understanding the mechanisms utilized by pathogens to overcome specific plant defensive compounds can be useful to increase plant resistance. Our study demonstrated that Sclerotinia shows different adaptation mechanisms, including detoxification systems, to grow and survive when plant protective compounds are present.
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Affiliation(s)
- Pari Madloo
- Group of Genetics, Breeding and Biochemistry of Brassicas, Misión Biológica de Galicia, Spanish Council for Scientific Research (MBG-CSIC), Pontevedra, Spain
- Department of Functional Biology, School of Biology, Universidade de Santiago de Compostela, Santiago, Spain
| | - Margarita Lema
- Department of Functional Biology, School of Biology, Universidade de Santiago de Compostela, Santiago, Spain
| | - Maria Elena Cartea
- Group of Genetics, Breeding and Biochemistry of Brassicas, Misión Biológica de Galicia, Spanish Council for Scientific Research (MBG-CSIC), Pontevedra, Spain
| | - Pilar Soengas
- Group of Genetics, Breeding and Biochemistry of Brassicas, Misión Biológica de Galicia, Spanish Council for Scientific Research (MBG-CSIC), Pontevedra, Spain
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17
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Lara-Gonzalez P, Pines J, Desai A. Spindle assembly checkpoint activation and silencing at kinetochores. Semin Cell Dev Biol 2021; 117:86-98. [PMID: 34210579 PMCID: PMC8406419 DOI: 10.1016/j.semcdb.2021.06.009] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/17/2021] [Accepted: 06/17/2021] [Indexed: 01/01/2023]
Abstract
The spindle assembly checkpoint (SAC) is a surveillance mechanism that promotes accurate chromosome segregation in mitosis. The checkpoint senses the attachment state of kinetochores, the proteinaceous structures that assemble onto chromosomes in mitosis in order to mediate their interaction with spindle microtubules. When unattached, kinetochores generate a diffusible inhibitor that blocks the activity of the anaphase-promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase required for sister chromatid separation and exit from mitosis. Work from the past decade has greatly illuminated our understanding of the mechanisms by which the diffusible inhibitor is assembled and how it inhibits the APC/C. However, less is understood about how SAC proteins are recruited to kinetochores in the absence of microtubule attachment, how the kinetochore catalyzes formation of the diffusible inhibitor, and how attachments silence the SAC at the kinetochore. Here, we summarize current understanding of the mechanisms that activate and silence the SAC at kinetochores and highlight open questions for future investigation.
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Affiliation(s)
- Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, USA; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA.
| | | | - Arshad Desai
- Ludwig Institute for Cancer Research, USA; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA.
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18
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Sane A, Sridhar S, Sanyal K, Ghosh SK. Shugoshin ensures maintenance of the spindle assembly checkpoint response and efficient spindle disassembly. Mol Microbiol 2021; 116:1079-1098. [PMID: 34407255 DOI: 10.1111/mmi.14796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/07/2021] [Accepted: 08/15/2021] [Indexed: 11/27/2022]
Abstract
Shugoshin proteins are evolutionarily conserved across eukaryotes, with some species-specific cellular functions, ensuring the fidelity of chromosome segregation. They act as adaptors at various subcellular locales to mediate several protein-protein interactions in a spatio-temporal manner. Here, we characterize shugoshin (Sgo1) in the human fungal pathogen Candida albicans. We observe that Sgo1 retains its centromeric localization and performs its conserved functions of regulating the sister chromatid biorientation, centromeric condensin localization, and maintenance of chromosomal passenger complex (CPC). We identify novel roles of Sgo1 as a spindle assembly checkpoint (SAC) component with functions in maintaining a prolonged SAC response by retaining Mad2 and Bub1 at the kinetochores in response to improper kinetochore-microtubule attachments. Strikingly, we discover the in vivo localization of Sgo1 along the length of the mitotic spindle. Our results indicate that Sgo1 performs a hitherto unknown function of facilitating timely disassembly of the mitotic spindle in C. albicans. To summarize, this study unravels a unique functional adaptation of shugoshin in maintaining genomic stability.
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Affiliation(s)
- Aakanksha Sane
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, India
| | - Shreyas Sridhar
- Molecular Biology & Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India.,Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Kaustuv Sanyal
- Molecular Biology & Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India.,Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Santanu K Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, India
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19
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Kops GJPL, Snel B, Tromer EC. Evolutionary Dynamics of the Spindle Assembly Checkpoint in Eukaryotes. Curr Biol 2021; 30:R589-R602. [PMID: 32428500 DOI: 10.1016/j.cub.2020.02.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The tremendous diversity in eukaryotic life forms can ultimately be traced back to evolutionary modifications at the level of molecular networks. Deep understanding of these modifications will not only explain cellular diversity, but will also uncover different ways to execute similar processes and expose the evolutionary 'rules' that shape the molecular networks. Here, we review the evolutionary dynamics of the spindle assembly checkpoint (SAC), a signaling network that guards fidelity of chromosome segregation. We illustrate how the interpretation of divergent SAC systems in eukaryotic species is facilitated by combining detailed molecular knowledge of the SAC and extensive comparative genome analyses. Ultimately, expanding this to other core cellular systems and experimentally interrogating such systems in organisms from all major lineages may start outlining the routes to and eventual manifestation of the cellular diversity of eukaryotic life.
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Affiliation(s)
- Geert J P L Kops
- Oncode Institute, Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences) and University Medical Centre Utrecht, Utrecht, The Netherlands.
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands.
| | - Eelco C Tromer
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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20
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de Groot C, Houston J, Davis B, Gerson-Gurwitz A, Monen J, Lara-Gonzalez P, Oegema K, Shiau AK, Desai A. The N-terminal tail of C. elegans CENP-A interacts with KNL-2 and is essential for centromeric chromatin assembly. Mol Biol Cell 2021; 32:1193-1201. [PMID: 33852350 PMCID: PMC8351560 DOI: 10.1091/mbc.e20-12-0798] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Centromeres are epigenetically defined by the centromere-specific histone H3 variant CENP-A. Specialized loading machinery, including the histone chaperone HJURP/Scm3, participates in CENP-A nucleosome assembly. However, Scm3/HJURP is missing from multiple lineages, including nematodes, with CENP-A-dependent centromeres. Here, we show that the extended N-terminal tail of Caenorhabditis elegans CENP-A contains a predicted structured region that is essential for centromeric chromatin assembly; removal of this region prevents CENP-A loading, resulting in failure of kinetochore assembly and defective chromosome condensation. By contrast, the N-tail mutant CENP-A localizes normally in the presence of endogenous CENP-A. The portion of the N-tail containing the predicted structured region binds to KNL-2, a conserved SANTA domain and Myb domain-containing protein (referred to as M18BP1 in vertebrates) specifically involved in CENP-A chromatin assembly. This direct interaction is conserved in the related nematode Caenorhabditis briggsae, despite divergence of the N-tail and KNL-2 primary sequences. Thus, the extended N-tail of CENP-A is essential for CENP-A chromatin assembly in C. elegans and partially substitutes for the function of Scm3/HJURP, in that it mediates a direct interaction between CENP-A and KNL-2. These results highlight an evolutionary variation on centromeric chromatin assembly in the absence of a dedicated CENP-A–specific chaperone/targeting factor of the Scm3/HJURP family.
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Affiliation(s)
- Christian de Groot
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA 92093.,Small Molecule Discovery Program, Ludwig Institute for Cancer Research, La Jolla, CA 92093
| | - Jack Houston
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA 92093
| | - Bethany Davis
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA 92093.,Small Molecule Discovery Program, Ludwig Institute for Cancer Research, La Jolla, CA 92093.,Department of Biology and Chemistry, Embry-Riddle Aeronautical University, Prescott, AZ 86301
| | - Adina Gerson-Gurwitz
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA 92093.,Small Molecule Discovery Program, Ludwig Institute for Cancer Research, La Jolla, CA 92093
| | - Joost Monen
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA 92093.,School of Theoretical & Applied Science, Ramapo College of New Jersey, Mahwah, NJ 07430
| | | | - Karen Oegema
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA 92093.,Section of Cell & Developmental Biology, Division of Biological Sciences and.,Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA 92093
| | - Andrew K Shiau
- Small Molecule Discovery Program, Ludwig Institute for Cancer Research, La Jolla, CA 92093.,Section of Cell & Developmental Biology, Division of Biological Sciences and
| | - Arshad Desai
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA 92093.,Section of Cell & Developmental Biology, Division of Biological Sciences and.,Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA 92093
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21
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Abstract
Accurate chromosome segregation is required for cell survival and organismal development. During mitosis, the spindle assembly checkpoint acts as a safeguard to maintain the high fidelity of mitotic chromosome segregation by monitoring the attachment of kinetochores to the mitotic spindle. Bub1 is a conserved kinase critical for the spindle assembly checkpoint. Bub1 also facilitates chromosome alignment and contributes to the regulation of mitotic duration. Here, focusing on the spindle assembly checkpoint and on chromosome alignment, we summarize the primary literature on Bub1, discussing its structure and functional domains, as well its regulation and roles in mitosis. In addition, we discuss recent evidence for roles of Bub1 beyond mitosis regulation in TGFβ signaling and telomere replication. Finally, we discuss the involvement of Bub1 in human diseases, especially in cancer, and the potential of using Bub1 as a drug target for therapeutic applications.
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Affiliation(s)
- Taekyung Kim
- Department of Biology Education, Pusan National University, Busan, Korea
| | - Anton Gartner
- IBS Center for Genomic Integrity, Ulsan, Korea.,School of Life Sciences, Ulsan National Institute of Science and Technology
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22
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Lara-Gonzalez P, Kim T, Oegema K, Corbett K, Desai A. A tripartite mechanism catalyzes Mad2-Cdc20 assembly at unattached kinetochores. Science 2021; 371:64-67. [PMID: 33384372 DOI: 10.1126/science.abc1424] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 11/17/2020] [Indexed: 12/22/2022]
Abstract
During cell division, kinetochores couple chromosomes to spindle microtubules. To protect against chromosome gain or loss, kinetochores lacking microtubule attachment locally catalyze association of the checkpoint proteins Cdc20 and Mad2, which is the key event in the formation of a diffusible checkpoint complex that prevents mitotic exit. We elucidated the mechanism of kinetochore-catalyzed Mad2-Cdc20 assembly with a probe that specifically monitors this assembly reaction at kinetochores in living cells. We found that catalysis occurs through a tripartite mechanism that includes localized delivery of Mad2 and Cdc20 substrates and two phosphorylation-dependent interactions that geometrically constrain their positions and prime Cdc20 for interaction with Mad2. These results reveal how unattached kinetochores create a signal that ensures genome integrity during cell division.
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Affiliation(s)
- Pablo Lara-Gonzalez
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA. .,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.,Ludwig Institute for Cancer Research, San Diego Branch, 9500 Gilman Drive, La Jolla, CA, USA
| | - Taekyung Kim
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.,Ludwig Institute for Cancer Research, San Diego Branch, 9500 Gilman Drive, La Jolla, CA, USA
| | - Karen Oegema
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.,Ludwig Institute for Cancer Research, San Diego Branch, 9500 Gilman Drive, La Jolla, CA, USA
| | - Kevin Corbett
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.,Ludwig Institute for Cancer Research, San Diego Branch, 9500 Gilman Drive, La Jolla, CA, USA
| | - Arshad Desai
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA. .,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.,Ludwig Institute for Cancer Research, San Diego Branch, 9500 Gilman Drive, La Jolla, CA, USA
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23
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Piano V, Alex A, Stege P, Maffini S, Stoppiello GA, Huis In 't Veld PJ, Vetter IR, Musacchio A. CDC20 assists its catalytic incorporation in the mitotic checkpoint complex. Science 2021; 371:67-71. [PMID: 33384373 DOI: 10.1126/science.abc1152] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 11/18/2020] [Indexed: 12/16/2022]
Abstract
Open (O) and closed (C) topologies of HORMA-domain proteins are respectively associated with inactive and active states of fundamental cellular pathways. The HORMA protein O-MAD2 converts to C-MAD2 upon binding CDC20. This is rate limiting for assembly of the mitotic checkpoint complex (MCC), the effector of a checkpoint required for mitotic fidelity. A catalyst assembled at kinetochores accelerates MAD2:CDC20 association through a poorly understood mechanism. Using a reconstituted SAC system, we discovered that CDC20 is an impervious substrate for which access to MAD2 requires simultaneous docking on several sites of the catalytic complex. Our analysis indicates that the checkpoint catalyst is substrate assisted and promotes MCC assembly through spatially and temporally coordinated conformational changes in both MAD2 and CDC20. This may define a paradigm for other HORMA-controlled systems.
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Affiliation(s)
- Valentina Piano
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany.
| | - Amal Alex
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Patricia Stege
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Gerardo A Stoppiello
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Pim J Huis In 't Veld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Ingrid R Vetter
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany. .,Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45141 Essen, Germany
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24
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Défachelles L, Russo AE, Nelson CR, Bhalla N. The conserved AAA-ATPase PCH-2 TRIP13 regulates spindle checkpoint strength. Mol Biol Cell 2020; 31:2219-2233. [PMID: 32697629 PMCID: PMC7550697 DOI: 10.1091/mbc.e20-05-0310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spindle checkpoint strength is dictated by the number of unattached kinetochores, cell volume, and cell fate. We show that the conserved AAA-ATPase PCH-2/TRIP13, which remodels the checkpoint effector Mad2 from an active conformation to an inactive one, controls checkpoint strength in Caenorhabditis elegans. Having previously established that this function is required for spindle checkpoint activation, we demonstrate that in cells genetically manipulated to decrease in cell volume, PCH-2 is no longer required for the spindle checkpoint or recruitment of Mad2 at unattached kinetochores. This role is not limited to large cells: the stronger checkpoint in germline precursor cells also depends on PCH-2. PCH-2 is enriched in germline precursor cells, and this enrichment relies on conserved factors that induce asymmetry in the early embryo. Finally, the stronger checkpoint in germline precursor cells is regulated by CMT-1, the ortholog of p31comet, which is required for both PCH-2′s localization to unattached kinetochores and its enrichment in germline precursor cells. Thus, PCH-2, likely by regulating the availability of inactive Mad2 at and near unattached kinetochores, governs checkpoint strength. This requirement may be particularly relevant in oocytes and early embryos enlarged for developmental competence, cells that divide in syncytial tissues, and immortal germline cells.
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Affiliation(s)
- Lénaïg Défachelles
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Anna E Russo
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Christian R Nelson
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Needhi Bhalla
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
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25
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Benzi G, Piatti S. Killing two birds with one stone: how budding yeast Mps1 controls chromosome segregation and spindle assembly checkpoint through phosphorylation of a single kinetochore protein. Curr Genet 2020; 66:1037-1044. [PMID: 32632756 DOI: 10.1007/s00294-020-01091-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 12/11/2022]
Abstract
During mitosis, the identical sister chromatids of each chromosome must attach through their kinetochores to microtubules emanating from opposite spindle poles. This process, referred to as chromosome biorientation, is essential for equal partitioning of the genetic information to the two daughter cells. Defects in chromosome biorientation can give rise to aneuploidy, a hallmark of cancer and genetic diseases. A conserved surveillance mechanism called spindle assembly checkpoint (SAC) prevents the onset of anaphase until biorientation is attained. Key to chromosome biorientation is an error correction mechanism that allows kinetochores to establish proper bipolar attachments by disengaging faulty kinetochore-microtubule connections. Error correction relies on the Aurora B and Mps1 kinases that also promote SAC signaling, raising the possibility that they are part of a single sensory device responding to improper attachments and concomitantly controlling both their disengagement and a temporary mitotic arrest. In budding yeast, Aurora B and Mps1 promote error correction independently from one another, but while the substrates of Aurora B in this process are at least partially known, the mechanism underlying the involvement of Mps1 in the error correction pathway is unknown. Through the characterization of a novel mps1 mutant and an unbiased genetic screen for extragenic suppressors, we recently gained evidence that a common mechanism based on Mps1-dependent phosphorylation of the Knl1/Spc105 kinetochore scaffold and subsequent recruitment of the Bub1 kinase is critical for the function of Mps1 in chromosome biorientation as well as for SAC activation (Benzi et al. EMBO Rep, 2020).
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Affiliation(s)
- Giorgia Benzi
- CRBM, University of Montpellier, CNRS, 1919 Route de Mende, 34293, Montpellier, France
| | - Simonetta Piatti
- CRBM, University of Montpellier, CNRS, 1919 Route de Mende, 34293, Montpellier, France.
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26
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Allan LA, Camacho Reis M, Ciossani G, Huis In 't Veld PJ, Wohlgemuth S, Kops GJ, Musacchio A, Saurin AT. Cyclin B1 scaffolds MAD1 at the kinetochore corona to activate the mitotic checkpoint. EMBO J 2020. [PMID: 32202322 DOI: 10.1525/embj.2019103180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023] Open
Abstract
Cyclin B:CDK1 is the master kinase regulator of mitosis. We show here that, in addition to its kinase functions, mammalian Cyclin B also scaffolds a localised signalling pathway to help preserve genome stability. Cyclin B1 localises to an expanded region of the outer kinetochore, known as the corona, where it scaffolds the spindle assembly checkpoint (SAC) machinery by binding directly to MAD1. In vitro reconstitutions map the key binding interface to a few acidic residues in the N-terminal region of MAD1, and point mutations in this sequence abolish MAD1 corona localisation and weaken the SAC. Therefore, Cyclin B1 is the long-sought-after scaffold that links MAD1 to the corona, and this specific pool of MAD1 is needed to generate a robust SAC response. Robustness arises because Cyclin B1:MAD1 localisation loses dependence on MPS1 kinase after the corona has been established, ensuring that corona-localised MAD1 can still be phosphorylated when MPS1 activity is low. Therefore, this study explains how corona-MAD1 generates a robust SAC signal, and it reveals a scaffolding role for the key mitotic kinase, Cyclin B1:CDK1, which ultimately helps to inhibit its own degradation.
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Affiliation(s)
- Lindsey A Allan
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Magda Camacho Reis
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Giuseppe Ciossani
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Pim J Huis In 't Veld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Sabine Wohlgemuth
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Geert Jpl Kops
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Adrian T Saurin
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, UK
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27
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Allan LA, Camacho Reis M, Ciossani G, Huis in ‘t Veld PJ, Wohlgemuth S, Kops GJPL, Musacchio A, Saurin AT. Cyclin B1 scaffolds MAD1 at the kinetochore corona to activate the mitotic checkpoint. EMBO J 2020; 39:e103180. [PMID: 32202322 PMCID: PMC7298293 DOI: 10.15252/embj.2019103180] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 01/20/2020] [Accepted: 03/02/2020] [Indexed: 11/28/2022] Open
Abstract
Cyclin B:CDK1 is the master kinase regulator of mitosis. We show here that, in addition to its kinase functions, mammalian Cyclin B also scaffolds a localised signalling pathway to help preserve genome stability. Cyclin B1 localises to an expanded region of the outer kinetochore, known as the corona, where it scaffolds the spindle assembly checkpoint (SAC) machinery by binding directly to MAD1. In vitro reconstitutions map the key binding interface to a few acidic residues in the N-terminal region of MAD1, and point mutations in this sequence abolish MAD1 corona localisation and weaken the SAC. Therefore, Cyclin B1 is the long-sought-after scaffold that links MAD1 to the corona, and this specific pool of MAD1 is needed to generate a robust SAC response. Robustness arises because Cyclin B1:MAD1 localisation loses dependence on MPS1 kinase after the corona has been established, ensuring that corona-localised MAD1 can still be phosphorylated when MPS1 activity is low. Therefore, this study explains how corona-MAD1 generates a robust SAC signal, and it reveals a scaffolding role for the key mitotic kinase, Cyclin B1:CDK1, which ultimately helps to inhibit its own degradation.
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Affiliation(s)
- Lindsey A Allan
- Division of Cellular MedicineSchool of MedicineUniversity of DundeeDundeeUK
| | - Magda Camacho Reis
- Division of Cellular MedicineSchool of MedicineUniversity of DundeeDundeeUK
| | - Giuseppe Ciossani
- Department of Mechanistic Cell BiologyMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Pim J Huis in ‘t Veld
- Department of Mechanistic Cell BiologyMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Sabine Wohlgemuth
- Department of Mechanistic Cell BiologyMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Geert JPL Kops
- Oncode InstituteHubrecht Institute—KNAW and University Medical Centre UtrechtUtrechtThe Netherlands
| | - Andrea Musacchio
- Department of Mechanistic Cell BiologyMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Adrian T Saurin
- Division of Cellular MedicineSchool of MedicineUniversity of DundeeDundeeUK
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28
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Jackman M, Marcozzi C, Barbiero M, Pardo M, Yu L, Tyson AL, Choudhary JS, Pines J. Cyclin B1-Cdk1 facilitates MAD1 release from the nuclear pore to ensure a robust spindle checkpoint. J Cell Biol 2020; 219:e201907082. [PMID: 32236513 PMCID: PMC7265330 DOI: 10.1083/jcb.201907082] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 02/05/2020] [Accepted: 03/06/2020] [Indexed: 11/22/2022] Open
Abstract
How the cell rapidly and completely reorganizes its architecture when it divides is a problem that has fascinated researchers for almost 150 yr. We now know that the core regulatory machinery is highly conserved in eukaryotes, but how these multiple protein kinases, protein phosphatases, and ubiquitin ligases are coordinated in space and time to remodel the cell in a matter of minutes remains a major question. Cyclin B1-Cdk is the primary kinase that drives mitotic remodeling; here we show that it is targeted to the nuclear pore complex (NPC) by binding an acidic face of the kinetochore checkpoint protein, MAD1, where it coordinates NPC disassembly with kinetochore assembly. Localized cyclin B1-Cdk1 is needed for the proper release of MAD1 from the embrace of TPR at the nuclear pore so that it can be recruited to kinetochores before nuclear envelope breakdown to maintain genomic stability.
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29
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Kops GJPL, Gassmann R. Crowning the Kinetochore: The Fibrous Corona in Chromosome Segregation. Trends Cell Biol 2020; 30:653-667. [PMID: 32386879 DOI: 10.1016/j.tcb.2020.04.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 01/30/2023]
Abstract
The kinetochore is at the heart of chromosome segregation in mitosis and meiosis. Rather than a static linker complex for chromatin and spindle microtubules, it is highly dynamic in composition, size, and shape. While known for decades that it can expand and grow a fibrous meshwork known as the corona, it was until recently unclear what constitutes this 'crown' and what its relevance is for kinetochore function. Here, we highlight recent discoveries in fibrous corona biology, and place them in the context of the processes that orchestrate high-fidelity chromosome segregation.
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Affiliation(s)
- Geert J P L Kops
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Centre Utrecht, Utrecht, 3584, CT, The Netherlands.
| | - Reto Gassmann
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.
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30
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Benzi G, Camasses A, Atsunori Y, Katou Y, Shirahige K, Piatti S. A common molecular mechanism underlies the role of Mps1 in chromosome biorientation and the spindle assembly checkpoint. EMBO Rep 2020; 21:e50257. [PMID: 32307893 DOI: 10.15252/embr.202050257] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/02/2020] [Accepted: 03/17/2020] [Indexed: 01/27/2023] Open
Abstract
The Mps1 kinase corrects improper kinetochore-microtubule attachments, thereby ensuring chromosome biorientation. Yet, its critical phosphorylation targets in this process remain largely elusive. Mps1 also controls the spindle assembly checkpoint (SAC), which halts chromosome segregation until biorientation is attained. Its role in SAC activation is antagonised by the PP1 phosphatase and involves phosphorylation of the kinetochore scaffold Knl1/Spc105, which in turn recruits the Bub1 kinase to promote assembly of SAC effector complexes. A crucial question is whether error correction and SAC activation are part of a single or separable pathways. Here, we isolate and characterise a new yeast mutant, mps1-3, that is severely defective in chromosome biorientation and SAC signalling. Through an unbiased screen for extragenic suppressors, we found that mutations lowering PP1 levels at Spc105 or forced association of Bub1 with Spc105 reinstate both chromosome biorientation and SAC signalling in mps1-3 cells. Our data argue that a common mechanism based on Knl1/Spc105 phosphorylation is critical for Mps1 function in error correction and SAC signalling, thus supporting the idea that a single sensory apparatus simultaneously elicits both pathways.
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Affiliation(s)
- Giorgia Benzi
- CRBM, University of Montpellier, CNRS, Montpellier, France
| | - Alain Camasses
- IGMM, University of Montpellier, CNRS, Montpellier, France
| | - Yoshimura Atsunori
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yuki Katou
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Katsuhiko Shirahige
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
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31
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Bel Borja L, Soubigou F, Taylor SJP, Fraguas Bringas C, Budrewicz J, Lara-Gonzalez P, Sorensen Turpin CG, Bembenek JN, Cheerambathur DK, Pelisch F. BUB-1 targets PP2A:B56 to regulate chromosome congression during meiosis I in C. elegans oocytes. eLife 2020; 9:65307. [PMID: 33355089 PMCID: PMC7787666 DOI: 10.7554/elife.65307] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 12/17/2020] [Indexed: 12/17/2022] Open
Abstract
Protein Phosphatase 2A (PP2A) is a heterotrimer composed of scaffolding (A), catalytic (C), and regulatory (B) subunits. PP2A complexes with B56 subunits are targeted by Shugoshin and BUBR1 to protect centromeric cohesion and stabilise kinetochore-microtubule attachments in yeast and mouse meiosis. In Caenorhabditis elegans, the closest BUBR1 orthologue lacks the B56-interaction domain and Shugoshin is not required for meiotic segregation. Therefore, the role of PP2A in C. elegans female meiosis is unknown. We report that PP2A is essential for meiotic spindle assembly and chromosome dynamics during C. elegans female meiosis. BUB-1 is the main chromosome-targeting factor for B56 subunits during prometaphase I. BUB-1 recruits PP2A:B56 to the chromosomes via a newly identified LxxIxE motif in a phosphorylation-dependent manner, and this recruitment is important for proper chromosome congression. Our results highlight a novel mechanism for B56 recruitment, essential for recruiting a pool of PP2A involved in chromosome congression during meiosis I.
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Affiliation(s)
- Laura Bel Borja
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Flavie Soubigou
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Samuel J P Taylor
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Conchita Fraguas Bringas
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Jacqueline Budrewicz
- Ludwig Institute for Cancer ResearchSan DiegoUnited States,Department of Cellular and Molecular Medicine, University of California, San DiegoSan DiegoUnited States
| | - Pablo Lara-Gonzalez
- Ludwig Institute for Cancer ResearchSan DiegoUnited States,Department of Cellular and Molecular Medicine, University of California, San DiegoSan DiegoUnited States
| | | | - Joshua N Bembenek
- Department of Molecular, Cellular, and Developmental Biology, University of MichiganAnn ArborUnited States
| | - Dhanya K Cheerambathur
- Wellcome Centre for Cell Biology & Institute of Cell Biology, School of Biological Sciences, The University of EdinburghEdinburghUnited Kingdom
| | - Federico Pelisch
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of DundeeDundeeUnited Kingdom
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32
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Lara-Gonzalez P, Moyle MW, Budrewicz J, Mendoza-Lopez J, Oegema K, Desai A. The G2-to-M Transition Is Ensured by a Dual Mechanism that Protects Cyclin B from Degradation by Cdc20-Activated APC/C. Dev Cell 2019; 51:313-325.e10. [PMID: 31588029 DOI: 10.1016/j.devcel.2019.09.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/26/2019] [Accepted: 09/05/2019] [Indexed: 12/23/2022]
Abstract
In the eukaryotic cell cycle, a threshold level of cyclin B accumulation triggers the G2-to-M transition, and subsequent cyclin B destruction triggers mitotic exit. The anaphase-promoting complex/cyclosome (APC/C) is the E3 ubiquitin ligase that, together with its co-activator Cdc20, targets cyclin B for destruction during mitotic exit. Here, we show that two pathways act in concert to protect cyclin B from Cdc20-activated APC/C in G2, in order to enable cyclin B accumulation and the G2-to-M transition. The first pathway involves the Mad1-Mad2 spindle checkpoint complex, acting in a distinct manner from checkpoint signaling after mitotic entry but employing a common molecular mechanism-the promotion of Mad2-Cdc20 complex formation. The second pathway involves cyclin-dependent kinase phosphorylation of Cdc20, which is known to reduce Cdc20's affinity for the APC/C. Cooperation of these two mechanisms, which target distinct APC/C binding interfaces of Cdc20, enables cyclin B accumulation and the G2-to-M transition.
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Affiliation(s)
- Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA; Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Mark W Moyle
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA; Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jacqueline Budrewicz
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA; Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jose Mendoza-Lopez
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA; Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karen Oegema
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA; Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Arshad Desai
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA; Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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33
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Pelisch F, Bel Borja L, Jaffray EG, Hay RT. Sumoylation regulates protein dynamics during meiotic chromosome segregation in C. elegans oocytes. J Cell Sci 2019; 132:jcs232330. [PMID: 31243051 PMCID: PMC6679583 DOI: 10.1242/jcs.232330] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 06/14/2019] [Indexed: 12/30/2022] Open
Abstract
Oocyte meiotic spindles in most species lack centrosomes and the mechanisms that underlie faithful chromosome segregation in acentrosomal meiotic spindles are not well understood. In C. elegans oocytes, spindle microtubules exert a poleward force on chromosomes that is dependent on the microtubule-stabilising protein CLS-2, the orthologue of the mammalian CLASP proteins. The checkpoint kinase BUB-1 and CLS-2 localise in the central spindle and display a dynamic localisation pattern throughout anaphase, but the signals regulating their anaphase-specific localisation remains unknown. We have shown previously that SUMO regulates BUB-1 localisation during metaphase I. Here, we found that SUMO modification of BUB-1 is regulated by the SUMO E3 ligase GEI-17 and the SUMO protease ULP-1. SUMO and GEI-17 are required for BUB-1 localisation between segregating chromosomes during early anaphase I. We also show that CLS-2 is subject to SUMO-mediated regulation; CLS-2 precociously localises in the midbivalent when either SUMO or GEI-17 are depleted. Overall, we provide evidence for a novel, SUMO-mediated control of protein dynamics during early anaphase I in oocytes.
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Affiliation(s)
- Federico Pelisch
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Laura Bel Borja
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Ellis G Jaffray
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Ronald T Hay
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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34
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BUB1 Is Essential for the Viability of Human Cells in which the Spindle Assembly Checkpoint Is Compromised. Cell Rep 2019; 22:1424-1438. [PMID: 29425499 DOI: 10.1016/j.celrep.2018.01.034] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/08/2018] [Accepted: 01/10/2018] [Indexed: 11/22/2022] Open
Abstract
The spindle assembly checkpoint (SAC) ensures faithful segregation of chromosomes. Although most mammalian cell types depend on the SAC for viability, we found that human HAP1 cells can grow SAC independently. We generated MAD1- and MAD2-deficient cells and mutagenized them to identify synthetic lethal interactions, revealing that chromosome congression factors become essential upon SAC deficiency. Besides expected hits, we also found that BUB1 becomes essential in SAC-deficient cells. We found that the BUB1 C terminus regulates alignment as well as recruitment of CENPF. Second, we found that BUBR1 was not essential in SAC-deficient HAP1 cells. We confirmed that BUBR1 does not regulate chromosome alignment in HAP1 cells and that BUB1 does not regulate chromosome alignment through BUBR1. Taken together, our data resolve some long-standing questions about the interplay between BUB1 and BUBR1 and their respective roles in the SAC and chromosome alignment.
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35
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Mad1 destabilizes p53 by preventing PML from sequestering MDM2. Nat Commun 2019; 10:1540. [PMID: 30948704 PMCID: PMC6449396 DOI: 10.1038/s41467-019-09471-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 03/12/2019] [Indexed: 02/06/2023] Open
Abstract
Mitotic arrest deficient 1 (Mad1) plays a well-characterized role in the mitotic checkpoint. However, interphase roles of Mad1 that do not impact mitotic checkpoint function remain largely uncharacterized. Here we show that upregulation of Mad1, which is common in human breast cancer, prevents stress-induced stabilization of the tumor suppressor p53 in multiple cell types. Upregulated Mad1 localizes to ProMyelocytic Leukemia (PML) nuclear bodies in breast cancer and cultured cells. The C-terminus of Mad1 directly interacts with PML, and this interaction is enhanced by sumoylation. PML stabilizes p53 by sequestering MDM2, an E3 ubiquitin ligase that targets p53 for degradation, to the nucleolus. Upregulated Mad1 displaces MDM2 from PML, freeing it to ubiquitinate p53. Upregulation of Mad1 accelerates growth of orthotopic mammary tumors, which show decreased levels of p53 and its downstream effector p21. These results demonstrate an unexpected interphase role for Mad1 in tumor promotion via p53 destabilization.
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36
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Recent Progress on the Localization of the Spindle Assembly Checkpoint Machinery to Kinetochores. Cells 2019; 8:cells8030278. [PMID: 30909555 PMCID: PMC6468716 DOI: 10.3390/cells8030278] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/13/2019] [Accepted: 03/16/2019] [Indexed: 12/14/2022] Open
Abstract
Faithful chromosome segregation during mitosis is crucial for maintaining genome stability. The spindle assembly checkpoint (SAC) is a surveillance mechanism that ensures accurate mitotic progression. Defective SAC signaling leads to premature sister chromatid separation and aneuploid daughter cells. Mechanistically, the SAC couples the kinetochore microtubule attachment status to the cell cycle progression machinery. In the presence of abnormal kinetochore microtubule attachments, the SAC prevents the metaphase-to-anaphase transition through a complex kinase-phosphatase signaling cascade which results in the correct balance of SAC components recruited to the kinetochore. The correct kinetochore localization of SAC proteins is a prerequisite for robust SAC signaling and, hence, accurate chromosome segregation. Here, we review recent progresses on the kinetochore recruitment of core SAC factors.
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37
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Pachis ST, Kops GJPL. Leader of the SAC: molecular mechanisms of Mps1/TTK regulation in mitosis. Open Biol 2019; 8:rsob.180109. [PMID: 30111590 PMCID: PMC6119859 DOI: 10.1098/rsob.180109] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 07/19/2018] [Indexed: 12/14/2022] Open
Abstract
Discovered in 1991 in a screen for genes involved in spindle pole body duplication, the monopolar spindle 1 (Mps1) kinase has since claimed a central role in processes that ensure error-free chromosome segregation. As a result, Mps1 kinase activity has become an attractive candidate for pharmaceutical companies in the search for compounds that target essential cellular processes to eliminate, for example, tumour cells or pathogens. Research in recent decades has offered many insights into the molecular function of Mps1 and its regulation. In this review, we integrate the latest knowledge regarding the regulation of Mps1 activity and its spatio-temporal distribution, highlight gaps in our understanding of these processes and propose future research avenues to address them.
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Affiliation(s)
- Spyridon T Pachis
- Oncode Institute, Hubrecht Institute - KNAW and University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Geert J P L Kops
- Oncode Institute, Hubrecht Institute - KNAW and University Medical Centre Utrecht, Utrecht, The Netherlands
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38
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Hoffmann G, Samel-Pommerencke A, Weber J, Cuomo A, Bonaldi T, Ehrenhofer-Murray AE. A role for CENP-A/Cse4 phosphorylation on serine 33 in deposition at the centromere. FEMS Yeast Res 2019; 18:4768140. [PMID: 29272409 DOI: 10.1093/femsyr/fox094] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/18/2017] [Indexed: 12/16/2022] Open
Abstract
Centromeres are the sites of assembly of the kinetochore, which connect the chromatids to the microtubules for sister chromatid segregation during cell division. Centromeres are characterized by the presence of the histone H3 variant CENP-A (termed Cse4 in Saccharomyces cerevisiae). Here, we investigated the function of serine 33 phosphorylation of Cse4 (Cse4-S33ph) in S. cerevisiae, which lies within the essential N-terminal domain (END) of the extended Cse4 N-terminus. Significantly, we identified histone H4-K5, 8, 12R to cause a temperature-sensitive growth defect with mutations in Cse4-S33 and sensitivity to nocodazole and hydroxyurea. Furthermore, the absence of Cse4-S33ph reduced the levels of Cse4 at centromeric sequences, suggesting that Cse4 deposition is defective in the absence of S33 phosphorylation. We furthermore identified synthetic genetic interactions with histone H2A-E57A and H2A-L66A, which both cause a reduced interaction with the histone chaperone FACT and reduced H2A/H2B levels in chromatin, again supporting the notion that a combined defect of H2A/H2B and Cse4 deposition causes centromeric defects. Altogether, our data highlight the importance of correct histone deposition in building a functional centromeric nucleosome and suggests a role for Cse4-S33ph in this process.
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Affiliation(s)
- Gesine Hoffmann
- Institut für Biologie, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | | | - Jan Weber
- Biozentrum Köln, Universität zu Köln, 50674 Köln, Germany
| | - Alessandro Cuomo
- Department of Experimental Oncology, European Institute of Oncology, 20139 Milano, Italy
| | - Tiziana Bonaldi
- Department of Experimental Oncology, European Institute of Oncology, 20139 Milano, Italy
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Pintard L, Bowerman B. Mitotic Cell Division in Caenorhabditis elegans. Genetics 2019; 211:35-73. [PMID: 30626640 PMCID: PMC6325691 DOI: 10.1534/genetics.118.301367] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/24/2018] [Indexed: 11/18/2022] Open
Abstract
Mitotic cell divisions increase cell number while faithfully distributing the replicated genome at each division. The Caenorhabditis elegans embryo is a powerful model for eukaryotic cell division. Nearly all of the genes that regulate cell division in C. elegans are conserved across metazoan species, including humans. The C. elegans pathways tend to be streamlined, facilitating dissection of the more redundant human pathways. Here, we summarize the virtues of C. elegans as a model system and review our current understanding of centriole duplication, the acquisition of pericentriolar material by centrioles to form centrosomes, the assembly of kinetochores and the mitotic spindle, chromosome segregation, and cytokinesis.
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Affiliation(s)
- Lionel Pintard
- Equipe labellisée Ligue contre le Cancer, Institut Jacques Monod, Team Cell Cycle and Development UMR7592, Centre National de la Recherche Scientifique - Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France
| | - Bruce Bowerman
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
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40
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Edwards F, Maton G, Gareil N, Canman JC, Dumont J. BUB-1 promotes amphitelic chromosome biorientation via multiple activities at the kinetochore. eLife 2018; 7:40690. [PMID: 30547880 PMCID: PMC6303103 DOI: 10.7554/elife.40690] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/13/2018] [Indexed: 12/03/2022] Open
Abstract
Accurate chromosome segregation relies on bioriented amphitelic attachments of chromosomes to microtubules of the mitotic spindle, in which sister chromatids are connected to opposite spindle poles. BUB-1 is a protein of the Spindle Assembly Checkpoint (SAC) that coordinates chromosome attachment with anaphase onset. BUB-1 is also required for accurate sister chromatid segregation independently of its SAC function, but the underlying mechanism remains unclear. Here we show that, in Caenorhabditis elegans embryos, BUB-1 accelerates the establishment of non-merotelic end-on kinetochore-microtubule attachments by recruiting the RZZ complex and its downstream partner dynein-dynactin at the kinetochore. In parallel, BUB-1 limits attachment maturation by the SKA complex. This activity opposes kinetochore-microtubule attachment stabilisation promoted by CLS-2CLASP-dependent kinetochore-microtubule assembly. BUB-1 is therefore a SAC component that coordinates the function of multiple downstream kinetochore-associated proteins to ensure accurate chromosome segregation.
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Affiliation(s)
- Frances Edwards
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Gilliane Maton
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Nelly Gareil
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Julie C Canman
- Department of Pathology and Cell Biology, Columbia University, New York, United States
| | - Julien Dumont
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, Paris, France
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41
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Pereira C, Reis RM, Gama JB, Celestino R, Cheerambathur DK, Carvalho AX, Gassmann R. Self-Assembly of the RZZ Complex into Filaments Drives Kinetochore Expansion in the Absence of Microtubule Attachment. Curr Biol 2018; 28:3408-3421.e8. [PMID: 30415699 PMCID: PMC6224608 DOI: 10.1016/j.cub.2018.08.056] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/24/2018] [Accepted: 08/24/2018] [Indexed: 01/06/2023]
Abstract
The kinetochore is a dynamic multi-protein assembly that forms on each sister chromatid and interacts with microtubules of the mitotic spindle to drive chromosome segregation. In animals, kinetochores without attached microtubules expand their outermost layer into crescent and ring shapes to promote microtubule capture and spindle assembly checkpoint (SAC) signaling. Kinetochore expansion is an example of protein co-polymerization, but the mechanism is not understood. Here, we present evidence that kinetochore expansion is driven by oligomerization of the Rod-Zw10-Zwilch (RZZ) complex, an outer kinetochore component that recruits the motor dynein and the SAC proteins Mad1-Mad2. Depletion of ROD in human cells suppresses kinetochore expansion, as does depletion of Spindly, the adaptor that connects RZZ to dynein, although dynein itself is dispensable. Expansion is also suppressed by mutating ZWILCH residues implicated in Spindly binding. Conversely, supplying cells with excess ROD facilitates kinetochore expansion under otherwise prohibitive conditions. Using the C. elegans early embryo, we demonstrate that ROD-1 has a concentration-dependent propensity for oligomerizing into micrometer-scale filaments, and we identify the ROD-1 β-propeller as a key regulator of self-assembly. Finally, we show that a minimal ROD-1-Zw10 complex efficiently oligomerizes into filaments in vitro. Our results suggest that RZZ's capacity for oligomerization is harnessed by kinetochores to assemble the expanded outermost domain, in which RZZ filaments serve as recruitment platforms for SAC components and microtubule-binding proteins. Thus, we propose that reversible RZZ self-assembly into filaments underlies the adaptive change in kinetochore size that contributes to chromosome segregation fidelity.
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Affiliation(s)
- Cláudia Pereira
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Rita M Reis
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - José B Gama
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Ricardo Celestino
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Dhanya K Cheerambathur
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Ana X Carvalho
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Reto Gassmann
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.
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42
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Saurin AT. Kinase and Phosphatase Cross-Talk at the Kinetochore. Front Cell Dev Biol 2018; 6:62. [PMID: 29971233 PMCID: PMC6018199 DOI: 10.3389/fcell.2018.00062] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/31/2018] [Indexed: 01/26/2023] Open
Abstract
Multiple kinases and phosphatases act on the kinetochore to control chromosome segregation: Aurora B, Mps1, Bub1, Plk1, Cdk1, PP1, and PP2A-B56, have all been shown to regulate both kinetochore-microtubule attachments and the spindle assembly checkpoint. Given that so many kinases and phosphatases converge onto two key mitotic processes, it is perhaps not surprising to learn that they are, quite literally, entangled in cross-talk. Inhibition of any one of these enzymes produces secondary effects on all the others, which results in a complicated picture that is very difficult to interpret. This review aims to clarify this picture by first collating the direct effects of each enzyme into one overarching schematic of regulation at the Knl1/Mis12/Ndc80 (KMN) network (a major signaling hub at the outer kinetochore). This schematic will then be used to discuss the implications of the cross-talk that connects these enzymes; both in terms of why it may be needed to produce the right type of kinetochore signals and why it nevertheless complicates our interpretations about which enzymes control what processes. Finally, some general experimental approaches will be discussed that could help to characterize kinetochore signaling by dissociating the direct from indirect effect of kinase or phosphatase inhibition in vivo. Together, this review should provide a framework to help understand how a network of kinases and phosphatases cooperate to regulate two key mitotic processes.
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Affiliation(s)
- Adrian T. Saurin
- Jacqui Wood Cancer Centre, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom
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43
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Luo Y, Ahmad E, Liu ST. MAD1: Kinetochore Receptors and Catalytic Mechanisms. Front Cell Dev Biol 2018; 6:51. [PMID: 29868582 PMCID: PMC5949338 DOI: 10.3389/fcell.2018.00051] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/18/2018] [Indexed: 12/22/2022] Open
Abstract
The mitotic checkpoint monitors kinetochore-microtubule attachment, delays anaphase onset and prevents aneuploidy when unattached or tensionless kinetochores are present in cells. Mitotic arrest deficiency 1 (MAD1) is one of the evolutionarily conserved core mitotic checkpoint proteins. MAD1 forms a cell cycle independent complex with MAD2 through its MAD2 interaction motif (MIM) in the middle region. Such a complex is enriched at unattached kinetochores and functions as an unusual catalyst to promote conformational change of additional MAD2 molecules, constituting a crucial signal amplifying mechanism for the mitotic checkpoint. Only MAD2 in its active conformation can be assembled with BUBR1 and CDC20 to form the Mitotic Checkpoint Complex (MCC), which is a potent inhibitor of anaphase onset. Recent research has shed light on how MAD1 is recruited to unattached kinetochores, and how it carries out its catalytic activity. Here we review these advances and discuss their implications for future research.
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Affiliation(s)
- Yibo Luo
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - Ejaz Ahmad
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - Song-Tao Liu
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
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44
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Hattersley N, Lara-Gonzalez P, Cheerambathur D, Gomez-Cavazos JS, Kim T, Prevo B, Khaliullin R, Lee KY, Ohta M, Green R, Oegema K, Desai A. Employing the one-cell C. elegans embryo to study cell division processes. Methods Cell Biol 2018; 144:185-231. [PMID: 29804670 DOI: 10.1016/bs.mcb.2018.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The one-cell Caenorhabditis elegans embryo offers many advantages for mechanistic analysis of cell division processes. Conservation of key genes and pathways involved in cell division makes findings in C. elegans broadly relevant. A key technical advantage of this system is the ability to penetrantly deplete essential gene products by RNA interference (RNAi) and replace them with wild-type or mutant versions expressed at endogenous levels from single copy RNAi-resistant transgene insertions. This ability to precisely perturb essential genes is complemented by the inherently highly reproducible nature of the zygotic division that facilitates development of quantitative imaging assays. Here, we detail approaches to generate targeted single copy transgene insertions that are RNAi-resistant, to engineer variants of individual genes employing transgene insertions as well as at the endogenous locus, and to in situ tag genes with fluorophores/purification tags. We also describe imaging assays and common image analysis tools employed to quantitatively monitor phenotypic effects of specific perturbations on meiotic and mitotic chromosome segregation, centrosome assembly/function, and cortical dynamics/cytokinesis.
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Affiliation(s)
- Neil Hattersley
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Dhanya Cheerambathur
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - J Sebastian Gomez-Cavazos
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Taekyung Kim
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Bram Prevo
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Renat Khaliullin
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Kian-Yong Lee
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Midori Ohta
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Rebecca Green
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Karen Oegema
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Arshad Desai
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States.
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45
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Gerhold AR, Poupart V, Labbé JC, Maddox PS. Spindle assembly checkpoint strength is linked to cell fate in the Caenorhabditis elegans embryo. Mol Biol Cell 2018; 29:1435-1448. [PMID: 29688794 PMCID: PMC6014101 DOI: 10.1091/mbc.e18-04-0215] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The spindle assembly checkpoint (SAC) is a conserved mitotic regulator that preserves genome stability by monitoring kinetochore-microtubule attachments and blocking anaphase onset until chromosome biorientation is achieved. Despite its central role in maintaining mitotic fidelity, the ability of the SAC to delay mitotic exit in the presence of kinetochore-microtubule attachment defects (SAC "strength") appears to vary widely. How different cellular aspects drive this variation remains largely unknown. Here we show that SAC strength is correlated with cell fate during development of Caenorhabditis elegans embryos, with germline-fated cells experiencing longer mitotic delays upon spindle perturbation than somatic cells. These differences are entirely dependent on an intact checkpoint and only partially attributable to differences in cell size. In two-cell embryos, cell size accounts for half of the difference in SAC strength between the larger somatic AB and the smaller germline P1 blastomeres. The remaining difference requires asymmetric cytoplasmic partitioning downstream of PAR polarity proteins, suggesting that checkpoint-regulating factors are distributed asymmetrically during early germ cell divisions. Our results indicate that SAC activity is linked to cell fate and reveal a hitherto unknown interaction between asymmetric cell division and the SAC.
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Affiliation(s)
- Abigail R Gerhold
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Succ. Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Vincent Poupart
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Succ. Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Jean-Claude Labbé
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Succ. Centre-ville, Montréal, QC H3C 3J7, Canada.,Department of Pathology and Cell Biology, Université de Montréal, Succ. Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Paul S Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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46
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Petsalaki E, Dandoulaki M, Zachos G. The ESCRT protein Chmp4c regulates mitotic spindle checkpoint signaling. J Cell Biol 2018; 217:861-876. [PMID: 29362225 PMCID: PMC5839794 DOI: 10.1083/jcb.201709005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 11/16/2017] [Accepted: 12/14/2017] [Indexed: 12/11/2022] Open
Abstract
The mitotic spindle checkpoint delays anaphase onset in the presence of unattached kinetochores, and efficient checkpoint signaling requires kinetochore localization of the Rod-ZW10-Zwilch (RZZ) complex. In the present study, we show that human Chmp4c, a protein involved in membrane remodeling, localizes to kinetochores in prometaphase but is reduced in chromosomes aligned at the metaphase plate. Chmp4c promotes stable kinetochore-microtubule attachments and is required for proper mitotic progression, faithful chromosome alignment, and segregation. Depletion of Chmp4c diminishes localization of RZZ and Mad1-Mad2 checkpoint proteins to prometaphase kinetochores and impairs mitotic arrest when microtubules are depolymerized by nocodazole. Furthermore, Chmp4c binds to ZW10 through a small C-terminal region, and constitutive Chmp4c kinetochore targeting causes a ZW10-dependent checkpoint metaphase arrest. In addition, Chmp4c spindle functions do not require endosomal sorting complex required for transport-dependent membrane remodeling. These results show that Chmp4c regulates the mitotic spindle checkpoint by promoting localization of the RZZ complex to unattached kinetochores.
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Affiliation(s)
- Eleni Petsalaki
- Department of Biology, University of Crete, Vassilika Vouton, Heraklion, Greece
| | - Maria Dandoulaki
- Department of Biology, University of Crete, Vassilika Vouton, Heraklion, Greece
| | - George Zachos
- Department of Biology, University of Crete, Vassilika Vouton, Heraklion, Greece
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47
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Simões PA, Celestino R, Carvalho AX, Gassmann R. NudE regulates dynein at kinetochores but is dispensable for other dynein functions in the C. elegans early embryo. J Cell Sci 2018; 131:jcs.212159. [PMID: 29192061 PMCID: PMC5818066 DOI: 10.1242/jcs.212159] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/27/2017] [Indexed: 12/12/2022] Open
Abstract
In mitosis, the molecular motor dynein is recruited to kinetochores by the Rod-Zw10-Zwilch complex (RZZ) and Spindly to control spindle assembly checkpoint (SAC) signaling and microtubule attachment. How the ubiquitous dynein co-factors Lis1 and NudE contribute to these functions remains poorly understood. Here, we show that the C. elegans NudE homolog NUD-2 is dispensable for dynein- and LIS-1-dependent mitotic spindle assembly in the zygote. This facilitates functional characterization of kinetochore-localized NUD-2, which is recruited by the CENP-F-like proteins HCP-1 and HCP-2 independently of RZZ-Spindly and dynein-LIS-1. Kinetochore dynein levels are reduced in Δnud-2 embryos, and, as occurs upon RZZ inhibition, loss of NUD-2 delays the formation of load-bearing kinetochore-microtubule attachments and causes chromatin bridges in anaphase. Survival of Δnud-2 embryos requires a functional SAC, and kinetochores without NUD-2 recruit an excess of SAC proteins. Consistent with this, SAC signaling in early Δnud-2 embryos extends mitotic duration and prevents high rates of chromosome mis-segregation. Our results reveal that both NUD-2 and RZZ-Spindly are essential for dynein function at kinetochores, and that the gain in SAC strength during early embryonic development is relevant under conditions that mildly perturb mitosis.
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Affiliation(s)
- Patrícia A Simões
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Ricardo Celestino
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana X Carvalho
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Reto Gassmann
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal .,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
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Hindriksen S, Lens SMA, Hadders MA. The Ins and Outs of Aurora B Inner Centromere Localization. Front Cell Dev Biol 2017; 5:112. [PMID: 29312936 PMCID: PMC5743930 DOI: 10.3389/fcell.2017.00112] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/04/2017] [Indexed: 01/12/2023] Open
Abstract
Error-free chromosome segregation is essential for the maintenance of genomic integrity during cell division. Aurora B, the enzymatic subunit of the Chromosomal Passenger Complex (CPC), plays a crucial role in this process. In early mitosis Aurora B localizes predominantly to the inner centromere, a specialized region of chromatin that lies at the crossroads between the inter-kinetochore and inter-sister chromatid axes. Two evolutionarily conserved histone kinases, Haspin and Bub1, control the positioning of the CPC at the inner centromere and this location is thought to be crucial for the CPC to function. However, recent studies sketch a subtler picture, in which not all functions of the CPC require strict confinement to the inner centromere. In this review we discuss the molecular pathways that direct Aurora B to the inner centromere and deliberate if and why this specific localization is important for Aurora B function.
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Affiliation(s)
- Sanne Hindriksen
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Susanne M A Lens
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Michael A Hadders
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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Mechanistic insight into TRIP13-catalyzed Mad2 structural transition and spindle checkpoint silencing. Nat Commun 2017; 8:1956. [PMID: 29208896 PMCID: PMC5717197 DOI: 10.1038/s41467-017-02012-2] [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: 07/01/2017] [Accepted: 11/01/2017] [Indexed: 01/20/2023] Open
Abstract
The spindle checkpoint maintains genomic stability and prevents aneuploidy. Unattached kinetochores convert the latent open conformer of the checkpoint protein Mad2 (O-Mad2) to the active closed conformer (C-Mad2), bound to Cdc20. C-Mad2–Cdc20 is incorporated into the mitotic checkpoint complex (MCC), which inhibits the anaphase-promoting complex/cyclosome (APC/C). The C-Mad2-binding protein p31comet and the ATPase TRIP13 promote MCC disassembly and checkpoint silencing. Here, using nuclear magnetic resonance (NMR) spectroscopy, we show that TRIP13 and p31comet catalyze the conversion of C-Mad2 to O-Mad2, without disrupting its stably folded core. We determine the crystal structure of human TRIP13, and identify functional TRIP13 residues that mediate p31comet–Mad2 binding and couple ATP hydrolysis to local unfolding of Mad2. TRIP13 and p31comet prevent APC/C inhibition by MCC components, but cannot reactivate APC/C already bound to MCC. Therefore, TRIP13–p31comet intercepts and disassembles free MCC not bound to APC/C through mediating the local unfolding of the Mad2 C-terminal region. The spindle checkpoint ensures the fidelity of chromosome segregation during mitosis and meiosis. Here the authors use a combination of biochemical and structural biology approaches to show how the TRIP13 ATPase and its adaptor, p31comet, catalyze the conversion of the checkpoint protein Mad2 between latent and active forms
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Tromer E, Bade D, Snel B, Kops GJPL. Phylogenomics-guided discovery of a novel conserved cassette of short linear motifs in BubR1 essential for the spindle checkpoint. Open Biol 2017; 6:rsob.160315. [PMID: 28003474 PMCID: PMC5204127 DOI: 10.1098/rsob.160315] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/01/2016] [Indexed: 11/12/2022] Open
Abstract
The spindle assembly checkpoint (SAC) maintains genomic integrity by preventing progression of mitotic cell division until all chromosomes are stably attached to spindle microtubules. The SAC critically relies on the paralogues Bub1 and BubR1/Mad3, which integrate kinetochore–spindle attachment status with generation of the anaphase inhibitory complex MCC. We previously reported on the widespread occurrences of independent gene duplications of an ancestral ‘MadBub’ gene in eukaryotic evolution and the striking parallel subfunctionalization that lead to loss of kinase function in BubR1/Mad3-like paralogues. Here, we present an elaborate subfunctionalization analysis of the Bub1/BubR1 gene family and perform de novo sequence discovery in a comparative phylogenomics framework to trace the distribution of ancestral sequence features to extant paralogues throughout the eukaryotic tree of life. We show that known ancestral sequence features are consistently retained in the same functional paralogue: GLEBS/CMI/CDII/kinase in the Bub1-like and KEN1/KEN2/D-Box in the BubR1/Mad3-like. The recently described ABBA motif can be found in either or both paralogues. We however discovered two additional ABBA motifs that flank KEN2. This cassette of ABBA1-KEN2-ABBA2 forms a strictly conserved module in all ancestral and BubR1/Mad3-like proteins, suggestive of a specific and crucial SAC function. Indeed, deletion of the ABBA motifs in human BUBR1 abrogates the SAC and affects APC/C–Cdc20 interactions. Our detailed comparative genomics analyses thus enabled discovery of a conserved cassette of motifs essential for the SAC and shows how this approach can be used to uncover hitherto unrecognized functional protein features.
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Affiliation(s)
- Eelco Tromer
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences), Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.,Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, 3584 CH, Utrecht, The Netherlands
| | - Debora Bade
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences), Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, 3584 CH, Utrecht, The Netherlands
| | - Geert J P L Kops
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences), Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands .,Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG, Utrecht, The Netherlands.,Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG, Utrecht, The Netherlands
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