1
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Chen C, Piano V, Alex A, Han SJY, Huis In 't Veld PJ, Roy B, Fergle D, Musacchio A, Joglekar AP. The structural flexibility of MAD1 facilitates the assembly of the Mitotic Checkpoint Complex. Nat Commun 2023; 14:1529. [PMID: 36934097 PMCID: PMC10024682 DOI: 10.1038/s41467-023-37235-z] [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: 06/26/2022] [Accepted: 03/08/2023] [Indexed: 03/20/2023] Open
Abstract
The spindle assembly checkpoint (SAC) safeguards the genome during cell division by generating an effector molecule known as the Mitotic Checkpoint Complex (MCC). The MCC comprises two subcomplexes: BUBR1:BUB3 and CDC20:MAD2, and the formation of CDC20:MAD2 is the rate-limiting step during MCC assembly. Recent studies show that the rate of CDC20:MAD2 formation is significantly accelerated by the cooperative binding of CDC20 to the SAC proteins MAD1 and BUB1. However, the molecular basis for this acceleration is not fully understood. Here, we demonstrate that the structural flexibility of MAD1 at a conserved hinge near the C-terminus is essential for catalytic MCC assembly. This MAD1 hinge enables the MAD1:MAD2 complex to assume a folded conformation in vivo. Importantly, truncating the hinge reduces the rate of MCC assembly in vitro and SAC signaling in vivo. Conversely, mutations that preserve hinge flexibility retain SAC signaling, indicating that the structural flexibility of the hinge, rather than a specific amino acid sequence, is important for SAC signaling. We summarize these observations as the 'knitting model' that explains how the folded conformation of MAD1:MAD2 promotes CDC20:MAD2 assembly.
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Affiliation(s)
- Chu Chen
- Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne, 50931, Germany
| | - Valentina Piano
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany
- Institute of Human Genetics, University Hospital Cologne, Cologne, 50931, Germany
| | - Amal Alex
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany
| | - Simon J Y Han
- Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Pim J Huis In 't Veld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany
| | - Babhrubahan Roy
- Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Daniel Fergle
- Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany
- Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen, 45141, Germany
| | - Ajit P Joglekar
- Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA.
- Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
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2
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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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3
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Villarroya-Beltri C, Osorio A, Torres-Ruiz R, Gómez-Sánchez D, Trakala M, Sánchez-Belmonte A, Mercadillo F, Hurtado B, Pitarch B, Hernández-Núñez A, Gómez-Caturla A, Rueda D, Perea J, Rodríguez-Perales S, Malumbres M, Urioste M. Biallelic germline mutations in MAD1L1 induce a syndrome of aneuploidy with high tumor susceptibility. SCIENCE ADVANCES 2022; 8:eabq5914. [PMID: 36322655 PMCID: PMC9629740 DOI: 10.1126/sciadv.abq5914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
Germline mutations leading to aneuploidy are rare, and their tumor-promoting properties are mostly unknown at the molecular level. We report here novel germline biallelic mutations in MAD1L1, encoding the spindle assembly checkpoint (SAC) protein MAD1, in a 36-year-old female with a dozen of neoplasias. Functional studies demonstrated lack of full-length protein and deficient SAC response, resulting in ~30 to 40% of aneuploid blood cells. Single-cell RNA analysis identified mitochondrial stress accompanied by systemic inflammation with enhanced interferon and NFκB signaling both in aneuploid and euploid cells, suggesting a non-cell autonomous response. MAD1L1 mutations resulted in specific clonal expansions of γδ T cells with chromosome 18 gains and enhanced cytotoxic profile as well as intermediate B cells with chromosome 12 gains and transcriptomic signatures characteristic of leukemia cells. These data point to MAD1L1 mutations as the cause of a new variant of mosaic variegated aneuploidy with systemic inflammation and unprecedented tumor susceptibility.
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Affiliation(s)
| | - Ana Osorio
- Familial Cancer Clinical Unit, CNIO, Madrid E-28029, Spain
| | - Raúl Torres-Ruiz
- Cytogenetic Unit, CNIO, Madrid E-28029, Spain
- Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
- Advanced Therapies Unit, Hematopoietic Innovative Therapies Division, Instituto de Investigación Sanitaria Fundacion Jimenez Díaz (IIS-FJD, UAM), Madrid E-28040, Spain
| | - David Gómez-Sánchez
- Hereditary Cancer Laboratory, Doce de Octubre University Hospital, i+12 Research Institute, Madrid, Spain
- Clinical and Translational Lung Cancer Research Unit, i+12 Research Institute and Biomedical Research Networking Center in Oncology (CIBERONC), Madrid, Spain
| | - Marianna Trakala
- Koch Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Agustin Sánchez-Belmonte
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | | | - Begoña Hurtado
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | - Borja Pitarch
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | | | | | - Daniel Rueda
- Hereditary Cancer Laboratory, Doce de Octubre University Hospital, i+12 Research Institute, Madrid, Spain
| | - José Perea
- Molecular Medicine Unit, Department of Medicine, Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain
- Surgery Department, Vithas Madrid Arturo Soria Hospital, Madrid, Spain
| | | | - Marcos Malumbres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | - Miguel Urioste
- Familial Cancer Clinical Unit, CNIO, Madrid E-28029, Spain
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4
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Roy B, Han SJY, Fontan AN, Jema S, Joglekar AP. Aurora B phosphorylates Bub1 to promote spindle assembly checkpoint signaling. Curr Biol 2022; 32:237-247.e6. [PMID: 34861183 PMCID: PMC8752509 DOI: 10.1016/j.cub.2021.10.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 08/24/2021] [Accepted: 10/22/2021] [Indexed: 01/12/2023]
Abstract
Accurate chromosome segregation during cell division requires amphitelic chromosome attachment to the spindle apparatus. It is ensured by the combined activity of the spindle assembly checkpoint (SAC),1 a signaling mechanism that delays anaphase onset in response to unattached chromosomes, and an error correction mechanism that eliminates syntelic attachments.2 The SAC becomes active when Mps1 kinase sequentially phosphorylates the kinetochore protein Spc105/KNL1 and the signaling proteins that Spc105/KNL1 recruits to facilitate the production of the mitotic checkpoint complex (MCC).3-8 The error correction mechanism is regulated by the Aurora B kinase, but Aurora B also promotes SAC signaling via indirect mechanisms.9-12 Here we present evidence that Aurora B kinase activity directly promotes MCC production by working downstream of Mps1 in budding yeast and human cells. Using the ectopic SAC activation (eSAC) system, we find that the conditional dimerization of Aurora B in budding yeast and an Aurora B recruitment domain in HeLa cells with either Bub1 or Mad1, but not the phosphodomain of Spc105/KNL1, leads to ectopic MCC production and mitotic arrest.13-16 Importantly, Bub1 must recruit both Mad1 and Cdc20 for this ectopic signaling activity. These and other data show that Aurora B cooperates with Bub1 to promote MCC production, but only after Mps1 licenses Bub1 recruitment to the kinetochore. This direct involvement of Aurora B in SAC signaling may maintain SAC signaling even after Mps1 activity in the kinetochore is lowered.
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Affiliation(s)
- Babhrubahan Roy
- Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Pl., Ann Arbor, MI-48109, USA
| | - Simon J. Y. Han
- Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Pl., Ann Arbor, MI-48109, USA,present address: Medical Scientist Training Program, University of Cincinnati College of Medicine, 3230 Eden Ave, Cincinnati, OH 45267, USA
| | - Adrienne N. Fontan
- Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Pl., Ann Arbor, MI-48109, USA,present address: Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, 455 Main St, Cambridge, MA 02142
| | - Soubhagyalaxmi Jema
- Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Pl., Ann Arbor, MI-48109, USA
| | - Ajit P. Joglekar
- Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Pl., Ann Arbor, MI-48109, USA,corresponding author, lead contact: , Twitter handle: @AjitJoglekar1
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5
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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: 99] [Impact Index Per Article: 33.0] [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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6
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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: 40] [Impact Index Per Article: 13.3] [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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7
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Cell-Size-Independent Spindle Checkpoint Failure Underlies Chromosome Segregation Error in Mouse Embryos. Curr Biol 2019; 29:865-873.e3. [PMID: 30773364 DOI: 10.1016/j.cub.2018.12.042] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/23/2018] [Accepted: 12/21/2018] [Indexed: 12/31/2022]
Abstract
Chromosome segregation errors during mammalian preimplantation development cause "mosaic" embryos comprising a mixture of euploid and aneuploid cells, which reduce the potential for a successful pregnancy [1-5], but why these errors are common is unknown. In most cells, chromosome segregation error is averted by the spindle assembly checkpoint (SAC), which prevents anaphase-promoting complex (APC/C) activation and anaphase onset until chromosomes are aligned with kinetochores attached to spindle microtubules [6, 7], but little is known about the SAC's role in the early mammalian embryo. In C. elegans, the SAC is weak in early embryos, and it strengthens during early embryogenesis as a result of progressively lessening cell size [8, 9]. Here, using live imaging, micromanipulation, gene knockdown, and pharmacological approaches, we show that this is not the case in mammalian embryos. Misaligned chromosomes in the early mouse embryo can recruit SAC components to mount a checkpoint signal, but this signal fails to prevent anaphase onset, leading to high levels of chromosome segregation error. We find that failure of the SAC to prolong mitosis is not attributable to cell size. We show that mild chemical inhibition of APC/C can extend mitosis, thereby allowing more time for correct chromosome alignment and reducing segregation errors. SAC-APC/C disconnect thus presents a mechanistic explanation for frequent chromosome segregation errors in early mammalian embryos. Moreover, our data provide proof of principle that modulation of the SAC-APC/C axis can increase the likelihood of error-free chromosome segregation in cultured mammalian embryos.
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8
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Vicente-Blázquez A, González M, Álvarez R, Del Mazo S, Medarde M, Peláez R. Antitubulin sulfonamides: The successful combination of an established drug class and a multifaceted target. Med Res Rev 2018; 39:775-830. [PMID: 30362234 DOI: 10.1002/med.21541] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/02/2018] [Accepted: 09/06/2018] [Indexed: 12/13/2022]
Abstract
Tubulin, the microtubules and their dynamic behavior are amongst the most successful antitumor, antifungal, antiparasitic, and herbicidal drug targets. Sulfonamides are exemplary drugs with applications in the clinic, in veterinary and in the agrochemical industry. This review summarizes the actual state and recent progress of both fields looking from the double point of view of the target and its drugs, with special focus onto the structural aspects. The article starts with a brief description of tubulin structure and its dynamic assembly and disassembly into microtubules and other polymers. Posttranslational modifications and the many cellular means of regulating and modulating tubulin's biology are briefly presented in the tubulin code. Next, the structurally characterized drug binding sites, their occupying drugs and the effects they induce are described, emphasizing on the structural requirements for high potency, selectivity, and low toxicity. The second part starts with a summary of the favorable and highly tunable combination of physical-chemical and biological properties that render sulfonamides a prototypical example of privileged scaffolds with representatives in many therapeutic areas. A complete description of tubulin-binding sulfonamides is provided, covering the different species and drug sites. Some of the antimitotic sulfonamides have met with very successful applications and others less so, thus illustrating the advances, limitations, and future perspectives of the field. All of them combine in a mechanism of action and a clinical outcome that conform efficient drugs.
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Affiliation(s)
- Alba Vicente-Blázquez
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Laboratory of Cell Death and Cancer Therapy, Department of Molecular Biomedicine, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Myriam González
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Raquel Álvarez
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Sara Del Mazo
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Manuel Medarde
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Rafael Peláez
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
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9
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Zhang G, Nilsson J. The closed form of Mad2 is bound to Mad1 and Cdc20 at unattached kinetochores. Cell Cycle 2018; 17:1087-1091. [PMID: 29895228 DOI: 10.1080/15384101.2018.1480209] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
Abstract
The spindle assembly checkpoint (SAC) ensures accurate chromosome segregation by delaying anaphase onset in response to unattached kinetochores. Anaphase is delayed by the generation of the mitotic checkpoint complex (MCC) composed of the checkpoint proteins Mad2 and BubR1/Bub3 bound to the protein Cdc20. Current models assume that MCC production is catalyzed at unattached kinetochores and that the Mad1/Mad2 complex is instrumental in the conversion of Mad2 from an open form (O-Mad2) to a closed form (C-Mad2) that can bind to Cdc20. Importantly the levels of Mad2 at kinetochores correlate with SAC activity but whether C-Mad2 at kinetochores exclusively represents its complex with Mad1 is not fully established. Here we use a recently established C-Mad2 specific monoclonal antibody to show that Cdc20 and C-Mad2 levels correlate at kinetochores and that depletion of Cdc20 reduces Mad2 but not Mad1 kinetochore levels. Importantly reintroducing wild type Cdc20 but not Cdc20 R132A, a mutant form that cannot bind Mad2, restores Mad2 levels. In agreement with this live cell imaging of fluorescent tagged Mad2 reveals that Cdc20 depletion strongly reduces Mad2 localization to kinetochores. These results support the presence of Mad2-Cdc20 complexes at kinetochores in agreement with current models of the SAC but also argue that Mad2 levels at kinetochores cannot be used as a direct readout of Mad1 levels.
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Affiliation(s)
- Gang Zhang
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of health and medical sciences , University of Copenhagen , Copenhagen , Denmark.,b Cancer Institute , The Affiliated Hospital of Qingdao University , Qingdao , China.,c Qingdao Cancer Institute , Qingdao , China
| | - Jakob Nilsson
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of health and medical sciences , University of Copenhagen , Copenhagen , Denmark
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10
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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: 18] [Impact Index Per Article: 3.0] [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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11
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Ji W, Luo Y, Ahmad E, Liu ST. Direct interactions of mitotic arrest deficient 1 (MAD1) domains with each other and MAD2 conformers are required for mitotic checkpoint signaling. J Biol Chem 2017; 293:484-496. [PMID: 29162720 DOI: 10.1074/jbc.ra117.000555] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 11/15/2017] [Indexed: 11/06/2022] Open
Abstract
As a sensitive signaling system, the mitotic checkpoint ensures faithful chromosome segregation by delaying anaphase onset even when a single kinetochore is unattached to mitotic spindle microtubules. The key signal amplification reaction for the checkpoint is the conformational conversion of "open" mitotic arrest deficient 2 (O-MAD2) into "closed" MAD2 (C-MAD2). The reaction has been suggested to be catalyzed by an unusual catalyst, a MAD1:C-MAD2 tetramer, but how the catalysis is executed and regulated remains elusive. Here, we report that in addition to the well-characterized middle region of MAD1 containing the MAD2-interaction motif (MIM), both N- and C-terminal domains (NTD and CTD) of MAD1 also contribute to mitotic checkpoint signaling. Unlike the MIM, which stably associated only with C-MAD2, the NTD and CTD in MAD1 surprisingly bound both O- and C-MAD2, suggesting that these two domains interact with both substrates and products of the O-to-C conversion. MAD1NTD and MAD1CTD also interacted with each other and with the MPS1 protein kinase, which phosphorylated both NTD and CTD. This phosphorylation decreased the NTD:CTD interaction and also CTD's interaction with MPS1. Of note, mutating the phosphorylation sites in the MAD1CTD, including Thr-716, compromised MAD2 binding and the checkpoint responses. We further noted that Ser-610 and Tyr-634 also contribute to the mitotic checkpoint signaling. Our results have uncovered that the MAD1NTD and MAD1CTD directly interact with each other and with MAD2 conformers and are regulated by MPS1 kinase, providing critical insights into mitotic checkpoint signaling.
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Affiliation(s)
- Wenbin Ji
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Yibo Luo
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Ejaz Ahmad
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Song-Tao Liu
- From the Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
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12
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Overlack K, Bange T, Weissmann F, Faesen AC, Maffini S, Primorac I, Müller F, Peters JM, Musacchio A. BubR1 Promotes Bub3-Dependent APC/C Inhibition during Spindle Assembly Checkpoint Signaling. Curr Biol 2017; 27:2915-2927.e7. [PMID: 28943088 PMCID: PMC5640511 DOI: 10.1016/j.cub.2017.08.033] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/16/2017] [Accepted: 08/15/2017] [Indexed: 12/25/2022]
Abstract
The spindle assembly checkpoint (SAC) prevents premature sister chromatid separation during mitosis. Phosphorylation of unattached kinetochores by the Mps1 kinase promotes recruitment of SAC machinery that catalyzes assembly of the SAC effector mitotic checkpoint complex (MCC). The SAC protein Bub3 is a phospho-amino acid adaptor that forms structurally related stable complexes with functionally distinct paralogs named Bub1 and BubR1. A short motif (“loop”) of Bub1, but not the equivalent loop of BubR1, enhances binding of Bub3 to kinetochore phospho-targets. Here, we asked whether the BubR1 loop directs Bub3 to different phospho-targets. The BubR1 loop is essential for SAC function and cannot be removed or replaced with the Bub1 loop. BubR1 loop mutants bind Bub3 and are normally incorporated in MCC in vitro but have reduced ability to inhibit the MCC target anaphase-promoting complex (APC/C), suggesting that BubR1:Bub3 recognition and inhibition of APC/C requires phosphorylation. Thus, small sequence differences in Bub1 and BubR1 direct Bub3 to different phosphorylated targets in the SAC signaling cascade. The molecular basis of kinetochore recruitment of Bub1 and BubR1 is dissected Bub1 and BubR1 modulate the ability of Bub3 to recognize phosphorylated targets A newly identified BubR1 motif targets Bub3 to the anaphase-promoting complex The newly identified motif of BubR1 is required for checkpoint signaling
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Affiliation(s)
- Katharina Overlack
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Tanja Bange
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Florian Weissmann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Alex C Faesen
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Ivana Primorac
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Franziska Müller
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany; Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstrasse, 45141 Essen, Germany.
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13
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Lane SIR, Morgan SL, Wu T, Collins JK, Merriman JA, ElInati E, Turner JM, Jones KT. DNA damage induces a kinetochore-based ATM/ATR-independent SAC arrest unique to the first meiotic division in mouse oocytes. Development 2017; 144:3475-3486. [PMID: 28851706 PMCID: PMC5665484 DOI: 10.1242/dev.153965] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 08/18/2017] [Indexed: 12/31/2022]
Abstract
Mouse oocytes carrying DNA damage arrest in meiosis I, thereby preventing creation of embryos with deleterious mutations. The arrest is dependent on activation of the spindle assembly checkpoint, which results in anaphase-promoting complex (APC) inhibition. However, little is understood about how this checkpoint is engaged following DNA damage. Here, we find that within minutes of DNA damage checkpoint proteins are assembled at the kinetochore, not at damage sites along chromosome arms, such that the APC is fully inhibited within 30 min. Despite this robust response, there is no measurable loss in k-fibres, or tension across the bivalent. Through pharmacological inhibition we observed that the response is dependent on Mps1 kinase, aurora kinase and Haspin. Using oocyte-specific knockouts we find the response does not require the DNA damage response kinases ATM or ATR. Furthermore, checkpoint activation does not occur in response to DNA damage in fully mature eggs during meiosis II, despite the divisions being separated by just a few hours. Therefore, mouse oocytes have a unique ability to sense DNA damage rapidly by activating the checkpoint at their kinetochores.
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Affiliation(s)
- Simon I R Lane
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Stephanie L Morgan
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Tianyu Wu
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Josie K Collins
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Julie A Merriman
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Elias ElInati
- Sex Chromosome Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - James M Turner
- Sex Chromosome Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Keith T Jones
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
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14
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Bub1 positions Mad1 close to KNL1 MELT repeats to promote checkpoint signalling. Nat Commun 2017; 8:15822. [PMID: 28604727 PMCID: PMC5472792 DOI: 10.1038/ncomms15822] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 05/03/2017] [Indexed: 12/21/2022] Open
Abstract
Proper segregation of chromosomes depends on a functional spindle assembly checkpoint (SAC) and requires kinetochore localization of the Bub1 and Mad1/Mad2 checkpoint proteins. Several aspects of Mad1/Mad2 kinetochore recruitment in human cells are unclear and in particular the underlying direct interactions. Here we show that conserved domain 1 (CD1) in human Bub1 binds directly to Mad1 and a phosphorylation site exists in CD1 that stimulates Mad1 binding and SAC signalling. Importantly, fusion of minimal kinetochore-targeting Bub1 fragments to Mad1 bypasses the need for CD1, revealing that the main function of Bub1 is to position Mad1 close to KNL1 MELT repeats. Furthermore, we identify residues in Mad1 that are critical for Mad1 functionality, but not Bub1 binding, arguing for a direct role of Mad1 in the checkpoint. This work dissects functionally relevant molecular interactions required for spindle assembly checkpoint signalling at kinetochores in human cells. The spindle assembly checkpoint ensures correct chromosome segregation and relies on kinetochore localization of the Bub1 and Mad1/Mad2 checkpoint proteins. Here the authors show that main function of Bub1 is to position Mad1 close to KNL1 MELT repeats in human cells.
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15
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Ozdian T, Holub D, Maceckova Z, Varanasi L, Rylova G, Rehulka J, Vaclavkova J, Slavik H, Moudry P, Znojek P, Stankova J, de Sanctis JB, Hajduch M, Dzubak P. Proteomic profiling reveals DNA damage, nucleolar and ribosomal stress are the main responses to oxaliplatin treatment in cancer cells. J Proteomics 2017; 162:73-85. [DOI: 10.1016/j.jprot.2017.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 04/26/2017] [Accepted: 05/02/2017] [Indexed: 12/18/2022]
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16
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Abstract
The kinase Mps1, long known to be the 'boss' in mitotic checkpoint signaling, phosphorylates multiple proteins in the checkpoint signaling cascade.
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Affiliation(s)
| | - Silke Hauf
- Department of Biological Sciences, Virginia Tech, Blacksburg, United States.,Biocomplexity Institute of Virginia Tech, Blacksburg, United States
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17
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Ji Z, Gao H, Jia L, Li B, Yu H. A sequential multi-target Mps1 phosphorylation cascade promotes spindle checkpoint signaling. eLife 2017; 6. [PMID: 28072388 PMCID: PMC5268738 DOI: 10.7554/elife.22513] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/09/2017] [Indexed: 12/18/2022] Open
Abstract
The master spindle checkpoint kinase Mps1 senses kinetochore-microtubule attachment and promotes checkpoint signaling to ensure accurate chromosome segregation. The kinetochore scaffold Knl1, when phosphorylated by Mps1, recruits checkpoint complexes Bub1–Bub3 and BubR1–Bub3 to unattached kinetochores. Active checkpoint signaling ultimately enhances the assembly of the mitotic checkpoint complex (MCC) consisting of BubR1–Bub3, Mad2, and Cdc20, which inhibits the anaphase-promoting complex or cyclosome bound to Cdc20 (APC/CCdc20) to delay anaphase onset. Using in vitro reconstitution, we show that Mps1 promotes APC/C inhibition by MCC components through phosphorylating Bub1 and Mad1. Phosphorylated Bub1 binds to Mad1–Mad2. Phosphorylated Mad1 directly interacts with Cdc20. Mutations of Mps1 phosphorylation sites in Bub1 or Mad1 abrogate the spindle checkpoint in human cells. Therefore, Mps1 promotes checkpoint activation through sequentially phosphorylating Knl1, Bub1, and Mad1. This sequential multi-target phosphorylation cascade makes the checkpoint highly responsive to Mps1 and to kinetochore-microtubule attachment. DOI:http://dx.doi.org/10.7554/eLife.22513.001
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Affiliation(s)
- Zhejian Ji
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Haishan Gao
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Luying Jia
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Bing Li
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Hongtao Yu
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
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18
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Abstract
The spindle assembly checkpoint (SAC) is a key mechanism to regulate the timing of mitosis and ensure that chromosomes are correctly segregated to daughter cells. The recruitment of the Mad1 and Mad2 proteins to the kinetochore is normally necessary for SAC activation. This recruitment is coordinated by the SAC kinase Mps1, which phosphorylates residues at the kinetochore to facilitate binding of Bub1, Bub3, Mad1, and Mad2. There is evidence that the essential function of Mps1 is to direct recruitment of Mad1/2. To test this model, we have systematically recruited Mad1, Mad2, and Mps1 to most proteins in the yeast kinetochore, and find that, while Mps1 is sufficient for checkpoint activation, recruitment of either Mad1 or Mad2 is not. These data indicate an important role for Mps1 phosphorylation in SAC activation, beyond the direct recruitment of Mad1 and Mad2.
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19
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Abstract
The spindle assembly checkpoint is a safeguard mechanism that coordinates cell-cycle progression during mitosis with the state of chromosome attachment to the mitotic spindle. The checkpoint prevents mitotic cells from exiting mitosis in the presence of unattached or improperly attached chromosomes, thus avoiding whole-chromosome gains or losses and their detrimental effects on cell physiology. Here, I review a considerable body of recent progress in the elucidation of the molecular mechanisms underlying checkpoint signaling, and identify a number of unresolved questions.
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Affiliation(s)
- Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany; Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen, Germany.
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20
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Sedgwick GG, Larsen MSY, Lischetti T, Streicher W, Jersie-Christensen RR, Olsen JV, Nilsson J. Conformation-specific anti-Mad2 monoclonal antibodies for the dissection of checkpoint signaling. MAbs 2016; 8:689-97. [PMID: 26986935 DOI: 10.1080/19420862.2016.1160988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The spindle assembly checkpoint (SAC) ensures accurate chromosome segregation during mitosis by delaying the activation of the anaphase-promoting complex/cyclosome (APC/C) in response to unattached kinetochores. The Mad2 protein is essential for a functional checkpoint because it binds directly to Cdc20, the mitotic co-activator of the APC/C, thereby inhibiting progression into anaphase. Mad2 exists in at least 2 different conformations, open-Mad2 (O-Mad2) and closed-Mad2 (C-Mad2), with the latter representing the active form that is able to bind Cdc20. Our ability to dissect Mad2 biology in vivo is limited by the absence of monoclonal antibodies (mAbs) useful for recognizing the different conformations of Mad2. Here, we describe and extensively characterize mAbs specific for either O-Mad2 or C-Mad2, as well as a pan-Mad2 antibody, and use these to investigate the different Mad2 complexes present in mitotic cells. Our antibodies validate current Mad2 models but also suggest that O-Mad2 can associate with checkpoint complexes, most likely through dimerization with C-Mad2. Furthermore, we investigate the makeup of checkpoint complexes bound to the APC/C, which indicate the presence of both Cdc20-BubR1-Bub3 and Mad2-Cdc20-BubR1-Bub3 complexes, with Cdc20 being ubiquitinated in both. Thus, our defined mAbs provide insight into checkpoint signaling and provide useful tools for future research on Mad2 function and regulation.
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Affiliation(s)
- Garry G Sedgwick
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Marie Sofie Yoo Larsen
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Tiziana Lischetti
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Werner Streicher
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Rosa Rakownikow Jersie-Christensen
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Jesper V Olsen
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Jakob Nilsson
- a The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
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21
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Nelson CR, Hwang T, Chen PH, Bhalla N. TRIP13PCH-2 promotes Mad2 localization to unattached kinetochores in the spindle checkpoint response. J Cell Biol 2015; 211:503-16. [PMID: 26527744 PMCID: PMC4639874 DOI: 10.1083/jcb.201505114] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/24/2015] [Indexed: 12/19/2022] Open
Abstract
The ability of the conserved ATPase TRIP13PCH-2 to disassemble a Mad2-containing complex is critical to promote the spindle checkpoint response by contributing to the robust localization of Mad2 to unattached kinetochores. The spindle checkpoint acts during cell division to prevent aneuploidy, a hallmark of cancer. During checkpoint activation, Mad1 recruits Mad2 to kinetochores to generate a signal that delays anaphase onset. Yet, whether additional factors contribute to Mad2’s kinetochore localization remains unclear. Here, we report that the conserved AAA+ ATPase TRIP13PCH-2 localizes to unattached kinetochores and is required for spindle checkpoint activation in Caenorhabditis elegans. pch-2 mutants effectively localized Mad1 to unattached kinetochores, but Mad2 recruitment was significantly reduced. Furthermore, we show that the C. elegans orthologue of the Mad2 inhibitor p31(comet)CMT-1 interacts with TRIP13PCH-2 and is required for its localization to unattached kinetochores. These factors also genetically interact, as loss of p31(comet)CMT-1 partially suppressed the requirement for TRIP13PCH-2 in Mad2 localization and spindle checkpoint signaling. These data support a model in which the ability of TRIP13PCH-2 to disassemble a p31(comet)/Mad2 complex, which has been well characterized in the context of checkpoint silencing, is also critical for spindle checkpoint activation.
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Affiliation(s)
- Christian R Nelson
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Tom Hwang
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Pin-Hsi Chen
- 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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22
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Zhao Y, Li L, Wu C, Jiang X, Ge B, Ren H, Huang F. Stable folding intermediates prevent fast interconversion between the closed and open states of Mad2 through its denatured state. Protein Eng Des Sel 2015; 29:23-9. [PMID: 26489879 DOI: 10.1093/protein/gzv056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 09/25/2015] [Indexed: 01/02/2023] Open
Abstract
Different states of metamorphic proteins can interconvert under physiological conditions to realize corresponding functions. The mechanism behind the conversion is critical for understanding how these proteins work. We report a combined thermodynamic and kinetic study on the folding/unfolding process of the open and closed conformers of mitotic arrest deficient protein 2 (Mad2), a metamorphic protein. It has been observed that open Mad2 (O-Mad2) can convert to closed Mad2 (C-Mad2). Our results show that O-Mad2 and C-Mad2 have similar thermodynamic stability, which explains the presence of metamorphosis. The folding/unfolding kinetics suggest that the conversion between O-Mad2 and C-Mad2 would be much faster than that reported previously if this conversion goes through the denatured state (U) directly, i.e. through an O-Mad2-denatured state (U)-C-Mad2 (O-U-C) pathway. This inconsistency implies that there exist stable intermediates in between the native and denatured states of Mad2, which would either slow down the O-U-C interconversion or prevent it going through the denatured state.
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Affiliation(s)
- Yuanyuan Zhao
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Huadong), Qingdao 266580, PR China Center for Bioengineering and Biotechnology, China University of Petroleum (Huadong), Qingdao 266580, PR China
| | - Lianghui Li
- Huangdao Community Health Service, Qingdao 266500, PR China
| | - Chunfei Wu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Huadong), Qingdao 266580, PR China Center for Bioengineering and Biotechnology, China University of Petroleum (Huadong), Qingdao 266580, PR China
| | - Xiaoyong Jiang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Huadong), Qingdao 266580, PR China Center for Bioengineering and Biotechnology, China University of Petroleum (Huadong), Qingdao 266580, PR China
| | - Baosheng Ge
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Huadong), Qingdao 266580, PR China Center for Bioengineering and Biotechnology, China University of Petroleum (Huadong), Qingdao 266580, PR China
| | - Hao Ren
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Huadong), Qingdao 266580, PR China Center for Bioengineering and Biotechnology, China University of Petroleum (Huadong), Qingdao 266580, PR China
| | - Fang Huang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Huadong), Qingdao 266580, PR China Center for Bioengineering and Biotechnology, China University of Petroleum (Huadong), Qingdao 266580, PR China
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23
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Zhang G, Lischetti T, Hayward DG, Nilsson J. Distinct domains in Bub1 localize RZZ and BubR1 to kinetochores to regulate the checkpoint. Nat Commun 2015; 6:7162. [PMID: 26031201 PMCID: PMC4458899 DOI: 10.1038/ncomms8162] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/10/2015] [Indexed: 12/29/2022] Open
Abstract
The spindle assembly checkpoint (SAC) ensures proper chromosome segregation by delaying anaphase onset in response to unattached kinetochores. Checkpoint signalling requires the kinetochore localization of the Mad1–Mad2 complex that in more complex eukaryotes depends on the Rod–Zwilch–ZW10 (RZZ) complex. The kinetochore protein Zwint has been proposed to be the kinetochore receptor for RZZ, but here we show that Bub1 and not Zwint is required for RZZ recruitment. We find that the middle region of Bub1 encompassing a domain essential for SAC signalling contributes to RZZ localization. In addition, we show that a distinct region in Bub1 mediates kinetochore localization of BubR1 through direct binding, but surprisingly removal of this region increases checkpoint strength. Our work thus uncovers how Bub1 coordinates checkpoint signalling by distinct domains for RZZ and BubR1 recruitment and suggests that Bub1 localizes antagonistic checkpoint activities. The spindle assembly checkpoint (SAC) depends on the recruitment of specific protein complexes to the kinetochore. Here Zhang et al. show that Bub1 recruits the RZZ complex and BubR1 to the kinetochore, and loss of the BubR1 binding sequence enhances checkpoint activity suggesting both SAC activating and silencing roles.
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Affiliation(s)
- Gang Zhang
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Tiziana Lischetti
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Daniel G Hayward
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Jakob Nilsson
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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24
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Lischetti T, Nilsson J. Regulation of mitotic progression by the spindle assembly checkpoint. Mol Cell Oncol 2015; 2:e970484. [PMID: 27308407 PMCID: PMC4905242 DOI: 10.4161/23723548.2014.970484] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/10/2014] [Accepted: 09/11/2014] [Indexed: 11/25/2022]
Abstract
Equal segregation of sister chromatids during mitosis requires that pairs of kinetochores establish proper attachment to microtubules emanating from opposite poles of the mitotic spindle. The spindle assembly checkpoint (SAC) protects against errors in segregation by delaying sister separation in response to improper kinetochore–microtubule interactions, and certain checkpoint proteins help to establish proper attachments. Anaphase entry is inhibited by the checkpoint through assembly of the mitotic checkpoint complex (MCC) composed of the 2 checkpoint proteins, Mad2 and BubR1, bound to Cdc20. The outer kinetochore acts as a catalyst for MCC production through the recruitment and proper positioning of checkpoint proteins and recently there has been remarkable progress in understanding how this is achieved. Here, we highlight recent advances in our understanding of kinetochore–checkpoint protein interactions and inhibition of the anaphase promoting complex by the MCC.
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Affiliation(s)
- Tiziana Lischetti
- The Novo Nordisk Foundation Center for Protein Research; Faculty of Health and Medical Sciences, University of Copenhagen ; Copenhagen, Denmark
| | - Jakob Nilsson
- The Novo Nordisk Foundation Center for Protein Research; Faculty of Health and Medical Sciences, University of Copenhagen ; Copenhagen, Denmark
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25
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London N, Biggins S. Signalling dynamics in the spindle checkpoint response. Nat Rev Mol Cell Biol 2014; 15:736-47. [PMID: 25303117 DOI: 10.1038/nrm3888] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The spindle checkpoint ensures proper chromosome segregation during cell division. Unravelling checkpoint signalling has been a long-standing challenge owing to the complexity of the structures and forces that regulate chromosome segregation. New reports have now substantially advanced our understanding of checkpoint signalling mechanisms at the kinetochore, the structure that connects microtubules and chromatin. In contrast to the traditional view of a binary checkpoint response - either completely on or off - new findings indicate that the checkpoint response strength is variable. This revised perspective provides insight into how checkpoint bypass can lead to aneuploidy and informs strategies to exploit these errors for cancer treatments.
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Affiliation(s)
- Nitobe London
- 1] Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N., PO Box 19024, Seattle, Washington 98109, USA. [2] Molecular and Cellular Biology Program, University of Washington/Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Sue Biggins
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N., PO Box 19024, Seattle, Washington 98109, USA
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Sacristan C, Kops GJPL. Joined at the hip: kinetochores, microtubules, and spindle assembly checkpoint signaling. Trends Cell Biol 2014; 25:21-8. [PMID: 25220181 DOI: 10.1016/j.tcb.2014.08.006] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 01/01/2023]
Abstract
Error-free chromosome segregation relies on stable connections between kinetochores and spindle microtubules. The spindle assembly checkpoint (SAC) monitors such connections and relays their absence to the cell cycle machinery to delay cell division. The molecular network at kinetochores that is responsible for microtubule binding is integrated with the core components of the SAC signaling system. Molecular-mechanistic understanding of how the SAC is coupled to the kinetochore-microtubule interface has advanced significantly in recent years. The latest insights not only provide a striking view of the dynamics and regulation of SAC signaling events at the outer kinetochore but also create a framework for understanding how that signaling may be terminated when kinetochores and microtubules connect.
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Affiliation(s)
- Carlos Sacristan
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Geert J P L Kops
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands.
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Rajanala K, Sarkar A, Jhingan GD, Priyadarshini R, Jalan M, Sengupta S, Nandicoori VK. Phosphorylation of nucleoporin Tpr governs its differential localization and is required for its mitotic function. J Cell Sci 2014; 127:3505-20. [PMID: 24938596 DOI: 10.1242/jcs.149112] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A major constituent of the nuclear basket region of the nuclear pore complex (NPC), nucleoporin Tpr, plays roles in regulating multiple important processes. We have previously established that Tpr is phosphorylated in both a MAP-kinase-dependent and MAP-kinase-independent manner, and that Tpr acts as both a substrate and as a scaffold for ERK2 (also known as MAPK1). Here, we report the identification of S2059 and S2094 as the major novel ERK-independent phosphorylation sites and T1677, S2020, S2023 and S2034 as additional ERK-independent phosphorylation sites found in the Tpr protein in vivo. Our results suggest that protein kinase A phosphorylates the S2094 residue and that the site is hyperphosphorylated during mitosis. Furthermore, we find that Tpr is phosphorylated at the S2059 residue by CDK1 and the phosphorylated form distinctly localizes with chromatin during telophase. Abrogation of S2059 phosphorylation abolishes the interaction of Tpr with Mad1, thus compromising the localization of both Mad1 and Mad2 proteins, resulting in cell cycle defects. The identification of novel phosphorylation sites on Tpr and the observations presented in this study allow better understanding of Tpr functions.
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Affiliation(s)
- Kalpana Rajanala
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India
| | - Anshuk Sarkar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India
| | - Gagan Deep Jhingan
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India
| | - Raina Priyadarshini
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India
| | - Manisha Jalan
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India
| | - Sagar Sengupta
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India
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28
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Abstract
The faithful segregation of chromosomes into daughter cells is essential for cellular and organismal viability. Errors in this process cause aneuploidy, a hallmark of cancer and several congenital diseases. For proper separation, chromosomes attach to microtubules of the mitotic spindle via their kinetochores, large protein structures assembled on centromeric chromatin. Kinetochores are also crucial for a cell cycle feedback mechanism known as the spindle assembly checkpoint (SAC). The SAC forces cells to remain in mitosis until all chromosomes are properly attached to microtubules. At the beginning of mitosis, the SAC proteins--Mad1, Mad2, Bub1, Bub3, BubR1, Mps1, and Cdc20--are recruited to kinetochores in a hierarchical and interdependent fashion (Fig 1A). There they monitor, in ways that are not fully clarified, the formation of kinetochore-microtubule attachments. Two studies recently published in EMBO reports by the groups of Silke Hauf and Jakob Nilsson, and a recent study by London and Biggins in Genes & Development, shed new light on the conserved SAC protein Mad1.
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Affiliation(s)
- Katharina Overlack
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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Heinrich S, Sewart K, Windecker H, Langegger M, Schmidt N, Hustedt N, Hauf S. Mad1 contribution to spindle assembly checkpoint signalling goes beyond presenting Mad2 at kinetochores. EMBO Rep 2014; 15:291-8. [PMID: 24477934 PMCID: PMC3989695 DOI: 10.1002/embr.201338114] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The spindle assembly checkpoint inhibits anaphase until all chromosomes have become attached to the mitotic spindle. A complex between the checkpoint proteins Mad1 and Mad2 provides a platform for Mad2:Mad2 dimerization at unattached kinetochores, which enables Mad2 to delay anaphase. Here, we show that mutations in Bub1 and within the Mad1 C-terminal domain impair the kinetochore localization of Mad1:Mad2 and abrogate checkpoint activity. Artificial kinetochore recruitment of Mad1 in these mutants co-recruits Mad2; however, the checkpoint remains non-functional. We identify specific mutations within the C-terminal head of Mad1 that impair checkpoint activity without affecting the kinetochore localization of Bub1, Mad1 or Mad2. Hence, Mad1 potentially in conjunction with Bub1 has a crucial role in checkpoint signalling in addition to presenting Mad2.
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Affiliation(s)
- Stephanie Heinrich
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
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