1
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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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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. 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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3
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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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4
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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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5
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Ibáñez de Opakua A, Geraets JA, Frieg B, Dienemann C, Savastano A, Rankovic M, Cima-Omori MS, Schröder GF, Zweckstetter M. Molecular interactions of FG nucleoporin repeats at high resolution. Nat Chem 2022; 14:1278-1285. [PMID: 36138110 PMCID: PMC9630130 DOI: 10.1038/s41557-022-01035-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 08/02/2022] [Indexed: 12/01/2022]
Abstract
Proteins that contain repeat phenylalanine-glycine (FG) residues phase separate into oncogenic transcription factor condensates in malignant leukaemias, form the permeability barrier of the nuclear pore complex and mislocalize in neurodegenerative diseases. Insights into the molecular interactions of FG-repeat nucleoporins have, however, remained largely elusive. Using a combination of NMR spectroscopy and cryoelectron microscopy, we have identified uniformly spaced segments of transient β-structure and a stable preformed α-helix recognized by messenger RNA export factors in the FG-repeat domain of human nucleoporin 98 (Nup98). In addition, we have determined at high resolution the molecular organization of reversible FG–FG interactions in amyloid fibrils formed by a highly aggregation-prone segment in Nup98. We have further demonstrated that amyloid-like aggregates of the FG-repeat domain of Nup98 have low stability and are reversible. Our results provide critical insights into the molecular interactions underlying the self-association and phase separation of FG-repeat nucleoporins in physiological and pathological cell activities. ![]()
Proteins rich in phenylalanine-glycine (FG) repeats can phase separate through FG–FG interactions. The molecular interactions of an important FG-repeat protein, nucleoporin 98, have now been studied in liquid-like transient and amyloid-like cohesive states. These interactions underlie the behaviour of FG-repeat proteins and their function in physiological and pathological cell activities.
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Affiliation(s)
| | - James A Geraets
- Institute of Biological Information Processing (Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Benedikt Frieg
- Institute of Biological Information Processing (Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Christian Dienemann
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Göttingen, Germany
| | | | - Marija Rankovic
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-based Structural Biology, Göttingen, Germany
| | | | - Gunnar F Schröder
- Institute of Biological Information Processing (Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany. .,Physics Department, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases, Göttingen, Germany. .,Max Planck Institute for Multidisciplinary Sciences, Department of NMR-based Structural Biology, Göttingen, Germany.
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6
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Silva PMA, Bousbaa H. BUB3, beyond the Simple Role of Partner. Pharmaceutics 2022; 14:pharmaceutics14051084. [PMID: 35631670 PMCID: PMC9147866 DOI: 10.3390/pharmaceutics14051084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/12/2022] [Accepted: 05/16/2022] [Indexed: 12/07/2022] Open
Abstract
The BUB3 protein plays a key role in the activation of the spindle assembly checkpoint (SAC), a ubiquitous surveillance mechanism that ensures the fidelity of chromosome segregation in mitosis and, consequently, prevents chromosome mis-segregation and aneuploidy. Besides its role in SAC signaling, BUB3 regulates chromosome attachment to the spindle microtubules. It is also involved in telomere replication and maintenance. Deficiency of the BUB3 gene has been closely linked to premature aging. Upregulation of the BUB3 gene has been found in a variety of human cancers and is associated with poor prognoses. Here, we review the structure and functions of BUB3 in mitosis, its expression in cancer and association with survival prognoses, and its potential as an anticancer target.
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Affiliation(s)
- Patrícia M. A. Silva
- UNIPRO—Oral Pathology and Rehabilitation Research Unit, University Institute of Health Sciences (IUCS), University Polytechnic Higher Education Cooperative (CESPU), Rua Central de Gandra, 4585-116 Gandra, Portugal;
- TOXRUN—Toxicology Research Unit, University Institute of Health Sciences (IUCS), University Polytechnic Higher Education Cooperative (CESPU), Rua Central de Gandra, 4585-116 Gandra, Portugal
| | - Hassan Bousbaa
- UNIPRO—Oral Pathology and Rehabilitation Research Unit, University Institute of Health Sciences (IUCS), University Polytechnic Higher Education Cooperative (CESPU), Rua Central de Gandra, 4585-116 Gandra, Portugal;
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
- Correspondence:
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7
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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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8
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Ribonucleic Acid Export 1 Is a Kinetochore-Associated Protein That Participates in Chromosome Alignment in Mouse Oocytes. Int J Mol Sci 2021; 22:ijms22094841. [PMID: 34063622 PMCID: PMC8125685 DOI: 10.3390/ijms22094841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/29/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
Ribonucleic acid export 1 (Rae1) is an important nucleoporin that participates in mRNA export during the interphase of higher eukaryotes and regulates the mitotic cell cycle. In this study, small RNA interference technology was used to knockdown Rae1, and immunofluorescence, immunoblotting, and chromosome spreading were used to study the role of Rae1 in mouse oocyte meiotic maturation. We found that Rae1 is a crucial regulator of meiotic maturation of mouse oocytes. After the resumption of meiosis (GVBD), Rae1 was concentrated on the kinetochore structure. The knockdown of Rae1 by a specific siRNA inhibited GVBD progression at 2 h, finally leading to a decreased 14 h polar body extrusion (PBE) rate. However, a comparable 14 h PBE rate was found in the control, and the Rae1 knockdown groups that had already undergone GVBD. Furthermore, we found elevated PBE after 9.5 h in the Rae1 knockdown oocytes. Further analysis revealed that Rae1 depletion significantly decreased the protein level of securin. In addition, we detected weakened kinetochore–microtubule (K-MT) attachments, misaligned chromosomes, and an increased incidence of aneuploidy in the Rae1 knockdown oocytes. Collectively, we propose that Rae1 modulates securin protein levels, which contribute to chromosome alignment, K-MT attachments, and aneuploidy in meiosis.
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9
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Shirnekhi HK, Herman JA, Paddison PJ, DeLuca JG. BuGZ facilitates loading of spindle assembly checkpoint proteins to kinetochores in early mitosis. J Biol Chem 2020; 295:14666-14677. [PMID: 32820050 DOI: 10.1074/jbc.ra120.013598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 08/07/2020] [Indexed: 11/06/2022] Open
Abstract
BuGZ is a kinetochore component that binds to and stabilizes Bub3, a key player in mitotic spindle assembly checkpoint signaling. Bub3 is required for kinetochore recruitment of Bub1 and BubR1, two proteins that have essential and distinct roles in the checkpoint. Both Bub1 and BubR1 localize to kinetochores through interactions with Bub3, which are mediated through conserved GLEBS domains in both Bub1 and BubR1. BuGZ also has a GLEBS domain, which is required for its kinetochore localization as well, presumably mediated through Bub3 binding. Although much is understood about the requirements for Bub1 and BubR1 interaction with Bub3 and kinetochores, much less is known regarding BuGZ's requirements. Here, we used a series of mutants to demonstrate that BuGZ kinetochore localization requires only its core GLEBS domain, which is distinct from the requirements for both Bub1 and BubR1. Furthermore, we found that the kinetics of Bub1, BubR1, and BuGZ loading to kinetochores differ, with BuGZ localizing prior to BubR1 and Bub1. To better understand how complexes containing Bub3 and its binding partners are loaded to kinetochores, we carried out size-exclusion chromatography and analyzed Bub3-containing complexes from cells under different spindle assembly checkpoint signaling conditions. We found that prior to kinetochore formation, Bub3 is complexed with BuGZ but not Bub1 or BubR1. Our results point to a model in which BuGZ stabilizes Bub3 and promotes Bub3 loading onto kinetochores in early mitosis, which, in turn, facilitates Bub1 and BubR1 kinetochore recruitment and spindle assembly checkpoint signaling.
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Affiliation(s)
- Hazheen K Shirnekhi
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Jacob A Herman
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Patrick J Paddison
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Jennifer G DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA.
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10
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Chien ML, Lai JH, Lin TF, Yang WS, Juang YL. NUP62 is required for the maintenance of the spindle assembly checkpoint and chromosomal stability. Int J Biochem Cell Biol 2020; 128:105843. [PMID: 32905854 DOI: 10.1016/j.biocel.2020.105843] [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: 05/14/2020] [Revised: 08/11/2020] [Accepted: 08/27/2020] [Indexed: 10/23/2022]
Abstract
The nuclear pore protein NUP62 localizes to spindle poles in mitosis and plays a role in maintaining centrosome homeostasis. In this study, we found that NUP62-depleted cells exhibited a defective spindle assembly checkpoint (SAC) and that depletion of NUP62 caused a slight decrease in MAD2 protein levels after nocodazole treatment. However, depletion of NUP62 did not cause a failure in kinetochore localization of the SAC proteins BUBR1, MAD1, and MAD2 in prometaphase. NUP62 depletion slightly prolonged mitotic timing but did not affect cell doubling time. In addition, NUP62 depletion caused a SAC defect and induced aneuploidy in human neural stem cells. Furthermore, overexpression of NUP62Q391P, a mutant protein causing autosomal recessive infantile bilateral striatal necrosis, resulted in a defect in the SAC, indicating that the amino acid residue Q391 in NUP62 is crucial for its effect on the SAC. Overall, we conclude that NUP62 maintains the SAC downstream of kinetochores and thereby ensures maintenance of chromosomal stability.
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Affiliation(s)
- Man-Ling Chien
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan
| | - Jian-Han Lai
- Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Division of Gastroenterology, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan; Mackay Medicine, Nursing and Management College, Taipei, Taiwan
| | - Ting-Fong Lin
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan
| | - Wan-Syuan Yang
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan
| | - Yue-Li Juang
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan.
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11
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Oh JH, Lee JY, Yu S, Cho Y, Hur S, Nam KT, Kim MH. RAE1 mediated ZEB1 expression promotes epithelial-mesenchymal transition in breast cancer. Sci Rep 2019; 9:2977. [PMID: 30814639 PMCID: PMC6393568 DOI: 10.1038/s41598-019-39574-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 01/24/2019] [Indexed: 12/21/2022] Open
Abstract
Breast cancer metastasis accounts for most of the deaths from breast cancer. Since epithelial-mesenchymal transition (EMT) plays an important role in promoting metastasis of cancer, many mechanisms regarding EMT have been studied. We previously showed that Ribonucleic acid export 1 (RAE1) is dysregulated in breast cancer and its overexpression leads to aggressive breast cancer phenotypes by inducing EMT. Here, we evaluated the functional capacity of RAE1 in breast cancer metastasis by using a three-dimensional (3D) culture system and xenograft models. Furthermore, to investigate the mechanisms of RAE1-driven EMT, in vitro studies were carried out. The induction of EMT with RAE1-overexpression was confirmed under the 3D culture system and in vivo system. Importantly, RAE1 mediates upregulation of an EMT marker ZEB1, by binding to the promoter region of ZEB1. Knockdown of ZEB1 in RAE1-overexpressing cells suppressed invasive and migratory behaviors, accompanied by an increase in epithelial and a decrease in mesenchymal markers. Taken together, these data demonstrate that RAE1 contributes to breast cancer metastasis by regulating a key EMT-inducing factor ZEB1 expression, suggesting its potential as a therapeutic target.
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Affiliation(s)
- Ji Hoon Oh
- Department of Anatomy, Embryology Laboratory, Yonsei University College of Medicine, Seoul, 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Ji-Yeon Lee
- Department of Anatomy, Embryology Laboratory, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Sungsook Yu
- Severance Biomedical Science Institute and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Yejin Cho
- Severance Biomedical Science Institute and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Sumin Hur
- Severance Biomedical Science Institute and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Ki Taek Nam
- Severance Biomedical Science Institute and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea.
| | - Myoung Hee Kim
- Department of Anatomy, Embryology Laboratory, Yonsei University College of Medicine, Seoul, 03722, Korea. .,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea.
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12
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Li F, Kim H, Ji Z, Zhang T, Chen B, Ge Y, Hu Y, Feng X, Han X, Xu H, Zhang Y, Yu H, Liu D, Ma W, Songyang Z. The BUB3-BUB1 Complex Promotes Telomere DNA Replication. Mol Cell 2019; 70:395-407.e4. [PMID: 29727616 DOI: 10.1016/j.molcel.2018.03.032] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 02/09/2018] [Accepted: 03/27/2018] [Indexed: 01/02/2023]
Abstract
Telomeres and telomere-binding proteins form complex secondary nucleoprotein structures that are critical for genome integrity but can present serious challenges during telomere DNA replication. It remains unclear how telomere replication stress is resolved during S phase. Here, we show that the BUB3-BUB1 complex, a component in spindle assembly checkpoint, binds to telomeres during S phase and promotes telomere DNA replication. Loss of the BUB3-BUB1 complex results in telomere replication defects, including fragile and shortened telomeres. We also demonstrate that the telomere-binding ability of BUB3 and kinase activity of BUB1 are indispensable to BUB3-BUB1 function at telomeres. TRF2 targets BUB1-BUB3 to telomeres, and BUB1 can directly phosphorylate TRF1 and promote TRF1 recruitment of BLM helicase to overcome replication stress. Our findings have uncovered previously unknown roles for the BUB3-BUB1 complex in S phase and shed light on how proteins from diverse pathways function coordinately to ensure proper telomere replication and maintenance.
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Affiliation(s)
- Feng Li
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Hyeung Kim
- Verna and Marrs Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Zhejian Ji
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Tianpeng Zhang
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Bohong Chen
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yuanlong Ge
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yang Hu
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Xuyang Feng
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Han
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Huimin Xu
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Youwei Zhang
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Hongtao Yu
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Dan Liu
- Verna and Marrs Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Wenbin Ma
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
| | - Zhou Songyang
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Oncology in South China, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; Verna and Marrs Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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13
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Dai XX, Xiong H, Zhang M, Sun S, Xiong B. Zfp207 is a Bub3 binding protein regulating meiotic chromosome alignment in mouse oocytes. Oncotarget 2017; 7:30155-65. [PMID: 27177335 PMCID: PMC5058671 DOI: 10.18632/oncotarget.9310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 05/01/2016] [Indexed: 02/07/2023] Open
Abstract
Zinc finger proteins are a massive, diverse family of proteins that serve a wide variety of biological functions. However, the roles of them during meiosis are not yet clearly defined. Here, we report that Zfp207 localizes at the kinetochores during mouse oocyte meiotic maturation. Depletion of Zfp207 leads to a significantly higher proportion of impaired spindle organization and misaligned chromosomes in oocytes. This is coupled with the defective kinetochore-microtubule attachments, and resultantly increasing incidence of aneuploid metaphase II eggs. The precocious polar body extrusion and escape of metaphase I arrest induced by nocodazole treatment in Zfp207-depleted oocytes indicates that Zfp207 is essential for activation of SAC (Spindle Assembly Checkpoint) activity. Notably, we find that Zfp207 binds to Bub3 to form a complex and maintains its protein level in oocytes, and that overexpression of Bub3 is able to partially rescue the occurrence of aneuploid eggs in Zfp207-depleted oocytes. Collectively, we identify Zfp207 as a novel Bub3 binding protein in oocytes which plays an important role in controlling meiotic chromosome alignment and SAC function.
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Affiliation(s)
- Xiao Xin Dai
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Hao Xiong
- The First Clinical Medical College, School of Medicine, Nanchang University, Nanchang, China
| | - Mianqun Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Shaochen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Bo Xiong
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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14
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Corbett KD. Molecular Mechanisms of Spindle Assembly Checkpoint Activation and Silencing. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:429-455. [PMID: 28840248 DOI: 10.1007/978-3-319-58592-5_18] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In eukaryotic cell division, the Spindle Assembly Checkpoint (SAC) plays a key regulatory role by monitoring the status of chromosome-microtubule attachments and allowing chromosome segregation only after all chromosomes are properly attached to spindle microtubules. While the identities of SAC components have been known, in some cases, for over two decades, the molecular mechanisms of the SAC have remained mostly mysterious until very recently. In the past few years, advances in biochemical reconstitution, structural biology, and bioinformatics have fueled an explosion in the molecular understanding of the SAC. This chapter seeks to synthesize these recent advances and place them in a biological context, in order to explain the mechanisms of SAC activation and silencing at a molecular level.
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Affiliation(s)
- Kevin D Corbett
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA.
- Departments of Cellular & Molecular Medicine and Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, 92093, USA.
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15
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Di Fiore B, Wurzenberger C, Davey NE, Pines J. The Mitotic Checkpoint Complex Requires an Evolutionary Conserved Cassette to Bind and Inhibit Active APC/C. Mol Cell 2016; 64:1144-1153. [PMID: 27939943 PMCID: PMC5179498 DOI: 10.1016/j.molcel.2016.11.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/12/2016] [Accepted: 10/31/2016] [Indexed: 12/26/2022]
Abstract
The Spindle Assembly Checkpoint (SAC) ensures genomic stability by preventing sister chromatid separation until all chromosomes are attached to the spindle. It catalyzes the production of the Mitotic Checkpoint Complex (MCC), which inhibits Cdc20 to inactivate the Anaphase Promoting Complex/Cyclosome (APC/C). Here we show that two Cdc20-binding motifs in BubR1 of the recently identified ABBA motif class are crucial for the MCC to recognize active APC/C-Cdc20. Mutating these motifs eliminates MCC binding to the APC/C, thereby abolishing the SAC and preventing cells from arresting in response to microtubule poisons. These ABBA motifs flank a KEN box to form a cassette that is highly conserved through evolution, both in the arrangement and spacing of the ABBA-KEN-ABBA motifs, and association with the amino-terminal KEN box required to form the MCC. We propose that the ABBA-KEN-ABBA cassette holds the MCC onto the APC/C by binding the two Cdc20 molecules in the MCC-APC/C complex.
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Affiliation(s)
- Barbara Di Fiore
- The Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge CB2 1QN, UK
| | - Claudia Wurzenberger
- The Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge CB2 1QN, UK
| | - Norman E Davey
- Conway Institute of Biomolecular and Biomedical Sciences, University College Dublin, Dublin 4, Ireland
| | - Jonathon Pines
- The Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge CB2 1QN, UK; Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK.
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16
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Bub3-Bub1 Binding to Spc7/KNL1 Toggles the Spindle Checkpoint Switch by Licensing the Interaction of Bub1 with Mad1-Mad2. Curr Biol 2016; 26:2642-2650. [PMID: 27618268 DOI: 10.1016/j.cub.2016.07.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/22/2016] [Accepted: 07/15/2016] [Indexed: 01/06/2023]
Abstract
The spindle assembly checkpoint (SAC) ensures that sister chromatids do not separate until all chromosomes are attached to spindle microtubules and bi-oriented. Spindle checkpoint proteins, including Mad1, Mad2, Mad3 (BubR1), Bub1, Bub3, and Mph1 (Mps1), are recruited to unattached and/or tensionless kinetochores. SAC activation catalyzes the conversion of soluble Mad2 (O-Mad2) into a form (C-Mad2) that binds Cdc20, BubR1, and Bub3 to form the mitotic checkpoint complex (MCC), a potent inhibitor of the anaphase-promoting complex (APC/C). SAC silencing de-represses Cdc20-APC/C activity allowing poly-ubiquitination of Securin and Cyclin B, leading to the dissolution of sister chromatids and anaphase onset [1]. Understanding how microtubule interaction at kinetochores influences the timing of anaphase requires an understanding of how spindle checkpoint protein interaction with the kinetochore influences spindle checkpoint signaling. We, and others, recently showed that Mph1 (Mps1) phosphorylates multiple conserved MELT motifs in the Spc7 (Spc105/KNL1) protein to recruit Bub1, Bub3, and Mad3 (BubR1) to kinetochores [2-4]. In budding yeast, Mps1 phosphorylation of a central non-catalytic region of Bub1 promotes its association with the Mad1-Mad2 complex, although this association has not yet been detected in other organisms [5]. Here we report that multisite binding of Bub3 to the Spc7 MELT array toggles the spindle checkpoint switch by permitting Mph1 (Mps1)-dependent interaction of Bub1 with Mad1-Mad2.
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17
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Salsi V, Fantini S, Zappavigna V. NUP98 fusion oncoproteins interact with the APC/C(Cdc20) as a pseudosubstrate and prevent mitotic checkpoint complex binding. Cell Cycle 2016; 15:2275-87. [PMID: 27097363 DOI: 10.1080/15384101.2016.1172156] [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: 10/21/2022] Open
Abstract
NUP98 is a recurrent partner gene in translocations causing acute myeloid leukemias and myelodisplastic syndrome. The expression of NUP98 fusion oncoproteins has been shown to induce mitotic spindle defects and chromosome missegregation, which correlate with the capability of NUP98 fusions to cause mitotic checkpoint attenuation. We show that NUP98 oncoproteins physically interact with the APC/C(Cdc20) in the absence of the NUP98 partner protein RAE1, and prevent the binding of the mitotic checkpoint complex to the APC/C(Cdc20). NUP98 oncoproteins require the GLEBS-like domain present in their NUP98 moiety to bind the APC/C(Cdc20). We found that NUP98 wild-type is a substrate of APC/C(Cdc20) prior to mitotic entry, and that its binding to APC/C(Cdc20) is controlled via phosphorylation of a PEST sequence located within its C-terminal portion. We identify S606, within the PEST sequence, as a key target site, whose phosphorylation modulates the capability of NUP98 to interact with APC/C(Cdc20). We finally provide evidence for an involvement of the peptidyl-prolyl isomerase PIN1 in modulating the possible conformational changes within NUP98 that lead to its dissociation from the APC/C(Cdc20) during mitosis. Our results provide novel insight into the mechanisms underlying the aberrant capability of NUP98 oncoproteins to interact with APC/C(Cdc20) and to interfere with its function.
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Affiliation(s)
- Valentina Salsi
- a Department of Life Sciences , University of Modena and Reggio Emilia , Modena , Italy
| | - Sebastian Fantini
- a Department of Life Sciences , University of Modena and Reggio Emilia , Modena , Italy
| | - Vincenzo Zappavigna
- a Department of Life Sciences , University of Modena and Reggio Emilia , Modena , Italy
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18
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Prinz F, Puetter V, Holton SJ, Andres D, Stegmann CM, Kwiatkowski D, Prechtl S, Petersen K, Beckmann G, Kreft B, Mumberg D, Fernández-Montalván A. Functional and Structural Characterization of Bub3·BubR1 Interactions Required for Spindle Assembly Checkpoint Signaling in Human Cells. J Biol Chem 2016; 291:11252-67. [PMID: 27030009 DOI: 10.1074/jbc.m115.702142] [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] [Received: 11/02/2015] [Indexed: 02/02/2023] Open
Abstract
The spindle assembly checkpoint (SAC) is an essential safeguarding mechanism devised to ensure equal chromosome distribution in daughter cells upon mitosis. The proteins Bub3 and BubR1 are key components of the mitotic checkpoint complex, an essential part of the molecular machinery on which the SAC relies. In the present work we have performed a detailed functional and biochemical characterization of the interaction between human Bub3 and BubR1 in cells and in vitro Our results demonstrate that genetic knockdown of Bub3 abrogates the SAC, promotes apoptosis, and inhibits the proliferation of human cancer cells. We also show that the integrity of the human mitotic checkpoint complex depends on the specific recognition between BubR1 and Bub3, for which the BubR1 Gle2 binding sequence motif is essential. This 1:1 binding event is high affinity, enthalpy-driven and with slow dissociation kinetics. The affinity, kinetics, and thermodynamic parameters of the interaction are differentially modulated by small regions in the N and C termini of the Gle2 binding domain sequence, suggesting the existence of "hotspots" for this protein-protein interaction. Furthermore, we show that specific disruption of endogenous BubR1·Bub3 complexes in human cancer cells phenocopies the effects observed in gene targeting experiments. Our work enhances the current understanding of key members of the SAC and paves the road for the pursuit of novel targeted cancer therapies based on SAC inhibition.
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Affiliation(s)
- Florian Prinz
- TRG Oncology, Bayer Pharma AG, Global Drug Discovery, 13353 Berlin, Germany
| | | | | | | | | | | | | | - Kirstin Petersen
- TRG Oncology, Bayer Pharma AG, Global Drug Discovery, 13353 Berlin, Germany
| | | | - Bertolt Kreft
- TRG Oncology, Bayer Pharma AG, Global Drug Discovery, 13353 Berlin, Germany
| | - Dominik Mumberg
- TRG Oncology, Bayer Pharma AG, Global Drug Discovery, 13353 Berlin, Germany
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19
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Derive N, Landmann C, Montembault E, Claverie MC, Pierre-Elies P, Goutte-Gattat D, Founounou N, McCusker D, Royou A. Bub3-BubR1-dependent sequestration of Cdc20Fizzy at DNA breaks facilitates the correct segregation of broken chromosomes. J Cell Biol 2016; 211:517-32. [PMID: 26553926 PMCID: PMC4639866 DOI: 10.1083/jcb.201504059] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BubR1 depends on its association with Bub3 to localize on DNA breaks during mitosis, where it sequesters Cdc20Fizzy and induces the inhibition of the APC/C locally, promoting the faithful segregation of broken chromatids. The presence of DNA double-strand breaks during mitosis is particularly challenging for the cell, as it produces broken chromosomes lacking a centromere. This situation can cause genomic instability resulting from improper segregation of the broken fragments into daughter cells. We recently uncovered a process by which broken chromosomes are faithfully transmitted via the BubR1-dependent tethering of the two broken chromosome ends. However, the mechanisms underlying BubR1 recruitment and function on broken chromosomes were largely unknown. We show that BubR1 requires interaction with Bub3 to localize on the broken chromosome fragments and to mediate their proper segregation. We also find that Cdc20, a cofactor of the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), accumulates on DNA breaks in a BubR1 KEN box–dependent manner. A biosensor for APC/C activity demonstrates a BubR1-dependent local inhibition of APC/C around the segregating broken chromosome. We therefore propose that the Bub3–BubR1 complex on broken DNA inhibits the APC/C locally via the sequestration of Cdc20, thus promoting proper transmission of broken chromosomes.
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Affiliation(s)
- Nicolas Derive
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Cedric Landmann
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Emilie Montembault
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Marie-Charlotte Claverie
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Priscillia Pierre-Elies
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Damien Goutte-Gattat
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Nabila Founounou
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Derek McCusker
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Anne Royou
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
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20
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Complex Commingling: Nucleoporins and the Spindle Assembly Checkpoint. Cells 2015; 4:706-25. [PMID: 26540075 PMCID: PMC4695854 DOI: 10.3390/cells4040706] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/12/2015] [Accepted: 10/28/2015] [Indexed: 12/14/2022] Open
Abstract
The segregation of the chromosomes during mitosis is an important process, in which the replicated DNA content is properly allocated into two daughter cells. To ensure their genomic integrity, cells present an essential surveillance mechanism known as the spindle assembly checkpoint (SAC), which monitors the bipolar attachment of the mitotic spindle to chromosomes to prevent errors that would result in chromosome mis-segregation and aneuploidy. Multiple components of the nuclear pore complex (NPC), a gigantic protein complex that forms a channel through the nuclear envelope to allow nucleocytoplasmic exchange of macromolecules, were shown to be critical for faithful cell division and implicated in the regulation of different steps of the mitotic process, including kinetochore and spindle assembly as well as the SAC. In this review, we will describe current knowledge about the interconnection between the NPC and the SAC in an evolutional perspective, which primarily relies on the two mitotic checkpoint regulators, Mad1 and Mad2. We will further discuss the role of NPC constituents, the nucleoporins, in kinetochore and spindle assembly and the formation of the mitotic checkpoint complex during mitosis and interphase.
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21
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Kim T, Moyle MW, Lara-Gonzalez P, De Groot C, Oegema K, Desai A. Kinetochore-localized BUB-1/BUB-3 complex promotes anaphase onset in C. elegans. ACTA ACUST UNITED AC 2015; 209:507-17. [PMID: 25987605 PMCID: PMC4442812 DOI: 10.1083/jcb.201412035] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/20/2015] [Indexed: 11/22/2022]
Abstract
In early C. elegans embryos, the kinetochore-localized BUB- 1/BUB-3 complex promotes anaphase onset independently of its roles in spindle checkpoint signaling and chromosome alignment. The conserved Bub1/Bub3 complex is recruited to the kinetochore region of mitotic chromosomes, where it initiates spindle checkpoint signaling and promotes chromosome alignment. Here we show that, in contrast to the expectation for a checkpoint pathway component, the BUB-1/BUB-3 complex promotes timely anaphase onset in Caenorhabditis elegans embryos. This activity of BUB-1/BUB-3 was independent of spindle checkpoint signaling but required kinetochore localization. BUB-1/BUB-3 inhibition equivalently delayed separase activation and other events occurring during mitotic exit. The anaphase promotion function required BUB-1’s kinase domain, but not its kinase activity, and this function was independent of the role of BUB-1/BUB-3 in chromosome alignment. These results reveal an unexpected role for the BUB-1/BUB-3 complex in promoting anaphase onset that is distinct from its well-studied functions in checkpoint signaling and chromosome alignment, and suggest a new mechanism contributing to the coordination of the metaphase-to-anaphase transition.
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Affiliation(s)
- Taekyung Kim
- Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037 Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Mark W Moyle
- Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037 Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Pablo Lara-Gonzalez
- Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037 Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Christian De Groot
- Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037 Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Karen Oegema
- Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037 Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Arshad Desai
- Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037 Ludwig Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037
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22
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Touati SA, Buffin E, Cladière D, Hached K, Rachez C, van Deursen JM, Wassmann K. Mouse oocytes depend on BubR1 for proper chromosome segregation but not for prophase I arrest. Nat Commun 2015; 6:6946. [PMID: 25897860 DOI: 10.1038/ncomms7946] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/16/2015] [Indexed: 12/19/2022] Open
Abstract
Mammalian female meiosis is error prone, with rates of meiotic chromosome missegregations strongly increasing towards the end of the reproductive lifespan. A strong reduction of BubR1 has been observed in oocytes of women approaching menopause and in ovaries of aged mice, which led to the hypothesis that a gradual decline of BubR1 contributes to age-related aneuploidization. Here we employ a conditional knockout approach in mouse oocytes to dissect the meiotic roles of BubR1. We show that BubR1 is required for diverse meiotic functions, including persistent spindle assembly checkpoint activity, timing of meiosis I and the establishment of robust kinetochore-microtubule attachments in a meiosis-specific manner, but not prophase I arrest. These data reveal that BubR1 plays a multifaceted role in chromosome segregation during the first meiotic division and suggest that age-related decline of BubR1 is a key determinant of the formation of aneuploid oocytes as women approach menopause.
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Affiliation(s)
- Sandra A Touati
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris Seine (IBPS), UMR7622, 75005 Paris, France.,CNRS, IBPS, UMR7622 Developmental Biology Lab, 75005 Paris, France
| | - Eulalie Buffin
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris Seine (IBPS), UMR7622, 75005 Paris, France.,CNRS, IBPS, UMR7622 Developmental Biology Lab, 75005 Paris, France
| | - Damien Cladière
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris Seine (IBPS), UMR7622, 75005 Paris, France.,CNRS, IBPS, UMR7622 Developmental Biology Lab, 75005 Paris, France
| | - Khaled Hached
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris Seine (IBPS), UMR7622, 75005 Paris, France.,CNRS, IBPS, UMR7622 Developmental Biology Lab, 75005 Paris, France
| | - Christophe Rachez
- Departement de Biologie du Développement et Cellules Souches, CNRS URA2578, Unité de Régulation Epigénétique, Institut Pasteur, 75015 Paris, France
| | - Jan M van Deursen
- Department of Pediatric and Adolescent Medicine and Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | - Katja Wassmann
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris Seine (IBPS), UMR7622, 75005 Paris, France.,CNRS, IBPS, UMR7622 Developmental Biology Lab, 75005 Paris, France
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23
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Abstract
Nuclear pore complexes (NPCs) are composed of several copies of ∼30 different proteins called nucleoporins (Nups). NPCs penetrate the nuclear envelope (NE) and regulate the nucleocytoplasmic trafficking of macromolecules. Beyond this vital role, NPC components influence genome functions in a transport-independent manner. Nups play an evolutionarily conserved role in gene expression regulation that, in metazoans, extends into the nuclear interior. Additionally, in proliferative cells, Nups play a crucial role in genome integrity maintenance and mitotic progression. Here we discuss genome-related functions of Nups and their impact on essential DNA metabolism processes such as transcription, chromosome duplication, and segregation.
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24
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Herman JA, Toledo CM, Olson JM, DeLuca JG, Paddison PJ. Molecular pathways: regulation and targeting of kinetochore-microtubule attachment in cancer. Clin Cancer Res 2014; 21:233-9. [PMID: 25104085 DOI: 10.1158/1078-0432.ccr-13-0645] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Kinetochores are large protein structures assembled on centromeric DNA during mitosis that bind to microtubules of the mitotic spindle to orchestrate and power chromosome movements. Deregulation of kinetochore-microtubule (KT-MT) attachments has been implicated in driving chromosome instability and cancer evolution; however, the nature and source of KT-MT attachment defects in cancer cells remain largely unknown. Here, we highlight recent findings suggesting that oncogene-driven changes in kinetochore regulation occur in glioblastoma multiforme (GBM) and possibly other cancers exhibiting chromosome instability, giving rise to novel therapeutic opportunities. In particular, we consider the GLE2p-binding sequence domains of BubR1 and the newly discovered BuGZ, two kinetochore-associated proteins, as candidate therapeutic targets for GBM.
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Affiliation(s)
- Jacob A Herman
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado
| | - Chad M Toledo
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington. Molecular and Cellular Biology Program, University of Washington, Seattle, Washington
| | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Jennifer G DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado.
| | - Patrick J Paddison
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington. Molecular and Cellular Biology Program, University of Washington, Seattle, Washington.
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25
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Takeda A, Yaseen NR. Nucleoporins and nucleocytoplasmic transport in hematologic malignancies. Semin Cancer Biol 2014; 27:3-10. [PMID: 24657637 DOI: 10.1016/j.semcancer.2014.02.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 11/19/2022]
Abstract
Hematologic malignancies are often associated with chromosomal rearrangements that lead to the expression of chimeric fusion proteins. Rearrangements of the genes encoding two nucleoporins, NUP98 and NUP214, have been implicated in the pathogenesis of several types of hematologic malignancies, particularly acute myeloid leukemia. NUP98 rearrangements result in fusion of an N-terminal portion of NUP98 to one of numerous proteins. These rearrangements often follow treatment with topoisomerase II inhibitors and tend to occur in younger patients. They have been shown to induce leukemia in mice and to enhance proliferation and disrupt differentiation in primary human hematopoietic precursors. NUP214 has only a few fusion partners. DEK-NUP214 is the most common NUP214 fusion in AML; it tends to occur in younger patients and is usually associated with FLT3 internal tandem duplications. The leukemogenic activity of NUP214 fusions is less well characterized. Normal nucleoporins, including NUP98 and NUP214, have important functions in nucleocytoplasmic transport, transcription, and mitosis. These functions and their disruptions by oncogenic nucleoporin fusions are discussed.
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Affiliation(s)
- Akiko Takeda
- Department of Pathology and Immunology, Washington University in St. Louis, United States.
| | - Nabeel R Yaseen
- Department of Pathology and Immunology, Washington University in St. Louis, United States.
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26
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De Souza CP, Hashmi SB, Osmani AH, Osmani SA. Application of a new dual localization-affinity purification tag reveals novel aspects of protein kinase biology in Aspergillus nidulans. PLoS One 2014; 9:e90911. [PMID: 24599037 PMCID: PMC3944740 DOI: 10.1371/journal.pone.0090911] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 02/04/2014] [Indexed: 12/22/2022] Open
Abstract
Filamentous fungi occupy critical environmental niches and have numerous beneficial industrial applications but devastating effects as pathogens and agents of food spoilage. As regulators of essentially all biological processes protein kinases have been intensively studied but how they regulate the often unique biology of filamentous fungi is not completely understood. Significant understanding of filamentous fungal biology has come from the study of the model organism Aspergillus nidulans using a combination of molecular genetics, biochemistry, cell biology and genomic approaches. Here we describe dual localization-affinity purification (DLAP) tags enabling endogenous N or C-terminal protein tagging for localization and biochemical studies in A. nidulans. To establish DLAP tag utility we endogenously tagged 17 protein kinases for analysis by live cell imaging and affinity purification. Proteomic analysis of purifications by mass spectrometry confirmed association of the CotA and NimXCdk1 kinases with known binding partners and verified a predicted interaction of the SldABub1/R1 spindle assembly checkpoint kinase with SldBBub3. We demonstrate that the single TOR kinase of A. nidulans locates to vacuoles and vesicles, suggesting that the function of endomembranes as major TOR cellular hubs is conserved in filamentous fungi. Comparative analysis revealed 7 kinases with mitotic specific locations including An-Cdc7 which unexpectedly located to mitotic spindle pole bodies (SPBs), the first such localization described for this family of DNA replication kinases. We show that the SepH septation kinase locates to SPBs specifically in the basal region of apical cells in a biphasic manner during mitosis and again during septation. This results in gradients of SepH between G1 SPBs which shift along hyphae as each septum forms. We propose that SepH regulates the septation initiation network (SIN) specifically at SPBs in the basal region of G1 cells and that localized gradients of SIN activity promote asymmetric septation.
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Affiliation(s)
- Colin P. De Souza
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Shahr B. Hashmi
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Aysha H. Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Stephen A. Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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27
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Jiang H, He X, Wang S, Jia J, Wan Y, Wang Y, Zeng R, Yates J, Zhu X, Zheng Y. A microtubule-associated zinc finger protein, BuGZ, regulates mitotic chromosome alignment by ensuring Bub3 stability and kinetochore targeting. Dev Cell 2014; 28:268-81. [PMID: 24462186 DOI: 10.1016/j.devcel.2013.12.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 12/09/2013] [Accepted: 12/20/2013] [Indexed: 11/28/2022]
Abstract
Equal chromosome segregation requires proper assembly of many proteins, including Bub3, onto kinetochores to promote kinetochore-microtubule interactions. By screening for mitotic regulators in the spindle envelope and matrix (Spemix), we identify a conserved Bub3 interacting and GLE-2-binding sequence (GLEBS) containing ZNF207 (BuGZ) that associates with spindle microtubules and regulates chromosome alignment. Using its conserved GLEBS, BuGZ directly binds and stabilizes Bub3. BuGZ also uses its microtubule-binding domain to enhance the loading of Bub3 to kinetochores that have assumed initial interactions with microtubules in prometaphase. This enhanced Bub3 loading is required for proper chromosome alignment and metaphase to anaphase progression. Interestingly, we show that microtubules are required for the highest kinetochore loading of Bub3, BubR1, and CENP-E during prometaphase. These findings suggest that BuGZ not only serves as a molecular chaperone for Bub3 but also enhances its loading onto kinetochores during prometaphase in a microtubule-dependent manner to promote chromosome alignment.
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Affiliation(s)
- Hao Jiang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA
| | - Xiaonan He
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Shusheng Wang
- Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA
| | - Junling Jia
- Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA
| | - Yihan Wan
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA
| | - Yueju Wang
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Rong Zeng
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - John Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xueliang Zhu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Yixian Zheng
- Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA.
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28
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Toledo CM, Herman JA, Olsen JB, Ding Y, Corrin P, Girard EJ, Olson JM, Emili A, DeLuca JG, Paddison PJ. BuGZ is required for Bub3 stability, Bub1 kinetochore function, and chromosome alignment. Dev Cell 2014; 28:282-94. [PMID: 24462187 DOI: 10.1016/j.devcel.2013.12.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 12/12/2013] [Accepted: 12/20/2013] [Indexed: 01/01/2023]
Abstract
During mitosis, the spindle assembly checkpoint (SAC) monitors the attachment of kinetochores (KTs) to the plus ends of spindle microtubules (MTs) and prevents anaphase onset until chromosomes are aligned and KTs are under proper tension. Here, we identify a SAC component, BuGZ/ZNF207, from an RNAi viability screen in human glioblastoma multiforme (GBM) brain tumor stem cells. BuGZ binds to and stabilizes Bub3 during interphase and mitosis through a highly conserved GLE2p-binding sequence (GLEBS) domain. Inhibition of BuGZ results in loss of both Bub3 and its binding partner Bub1 from KTs, reduction of Bub1-dependent phosphorylation of centromeric histone H2A, attenuation of KT-based Aurora B kinase activity, and lethal chromosome congression defects in cancer cells. Phylogenetic analysis indicates that BuGZ orthologs are highly conserved among eukaryotes, but are conspicuously absent from budding and fission yeasts. These findings suggest that BuGZ has evolved to facilitate Bub3 activity and chromosome congression in higher eukaryotes.
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Affiliation(s)
- Chad M Toledo
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Jacob A Herman
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Jonathan B Olsen
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Yu Ding
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Philip Corrin
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Emily J Girard
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Andrew Emili
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jennifer G DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.
| | - Patrick J Paddison
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA.
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29
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Salsi V, Ferrari S, Gorello P, Fantini S, Chiavolelli F, Mecucci C, Zappavigna V. NUP98 fusion oncoproteins promote aneuploidy by attenuating the mitotic spindle checkpoint. Cancer Res 2013; 74:1079-90. [PMID: 24371226 DOI: 10.1158/0008-5472.can-13-0912] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
NUP98 is a recurrent fusion partner in chromosome translocations that cause acute myelogenous leukemia. NUP98, a nucleoporin, and its interaction partner Rae1, have been implicated in the control of chromosome segregation, but their mechanistic contributions to tumorigenesis have been unclear. Here, we show that expression of NUP98 fusion oncoproteins causes mitotic spindle defects and chromosome missegregation, correlating with the capability of NUP98 fusions to cause premature securin degradation and slippage from an unsatisfied spindle assembly checkpoint (SAC). NUP98 fusions, unlike wild-type NUP98, were found to physically interact with the anaphase promoting complex/cyclosome (APC/C)(Cdc20) and to displace the BubR1 SAC component, suggesting a possible mechanistic basis for their interference with SAC function. In addition, NUP98 oncoproteins displayed a prolonged half-life in cells. We found that NUP98 stability is controlled by a PEST sequence, absent in NUP98 oncoproteins, whose deletion reproduced the aberrant SAC-interfering activity of NUP98 oncoproteins. Together, our findings suggest that NUP98 oncoproteins predispose myeloid cells to oncogenic transformation or malignant progression by promoting whole chromosome instability.
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Affiliation(s)
- Valentina Salsi
- Authors' Affiliations: Department of Life Sciences, University of Modena and Reggio Emilia, Modena; and Department of Hematology, University of Perugia, University Hospital S. Maria della Misericordia, Perugia, Italy
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30
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Primorac I, Weir JR, Chiroli E, Gross F, Hoffmann I, van Gerwen S, Ciliberto A, Musacchio A. Bub3 reads phosphorylated MELT repeats to promote spindle assembly checkpoint signaling. eLife 2013; 2:e01030. [PMID: 24066227 PMCID: PMC3779320 DOI: 10.7554/elife.01030] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 08/21/2013] [Indexed: 12/31/2022] Open
Abstract
Regulation of macromolecular interactions by phosphorylation is crucial in signaling networks. In the spindle assembly checkpoint (SAC), which enables errorless chromosome segregation, phosphorylation promotes recruitment of SAC proteins to tensionless kinetochores. The SAC kinase Mps1 phosphorylates multiple Met-Glu-Leu-Thr (MELT) motifs on the kinetochore subunit Spc105/Knl1. The phosphorylated MELT motifs (MELTP) then promote recruitment of downstream signaling components. How MELTP motifs are recognized is unclear. In this study, we report that Bub3, a 7-bladed β-propeller, is the MELTP reader. It contains an exceptionally well-conserved interface that docks the MELTP sequence on the side of the β-propeller in a previously unknown binding mode. Mutations targeting the Bub3 interface prevent kinetochore recruitment of the SAC kinase Bub1. Crucially, they also cause a checkpoint defect, showing that recognition of phosphorylated targets by Bub3 is required for checkpoint signaling. Our data provide the first detailed mechanistic insight into how phosphorylation promotes recruitment of checkpoint proteins to kinetochores. DOI:http://dx.doi.org/10.7554/eLife.01030.001 The cell cycle is the process by which a cell divides to produce two near-identical daughter cells. Two crucial parts of the cell cycle are the duplication of the chromosomes in the original cell, and the segregation of these chromosomes between the two daughter cells. These and other parts of the cell cycle are strictly regulated to prevent errors, which can lead to cancer and other diseases. After chromosome duplication has taken place, the pairs of identical chromosomes, known as sister chromatids, remain tightly bound to each other. These sister chromatids line up in the middle of the cell, with protein filaments called microtubules connecting them to a bipolar structure called the spindle. For the cell to divide correctly, the sister chromatids in each pair must be connected to opposite poles of the spindle. A signalling network known as the spindle assembly checkpoint (SAC) ensures that the sister chromatids have enough time to line up correctly and to correct possible problems. Once everything is in place, the SAC releases its ‘break’, and the microtubules then pull the sister chromatids away from each other. This way, each daughter cell receives the same complement of chromosomes that was present in the mother cell. The microtubules are not directly attached to the sister chromatids but to protein complexes called kinetochores that assemble on each sister chromatid. In particular, each microtubule binds to a very large protein complex called the KMN network. Knl1, which is part of this network, recruits two SAC proteins–Bub1 and Bub3–to the kinetochore. It is known that a phosphate group is added to Knl1 when the SAC is active, and that Knl1 can only recruit Bub1 and Bub3 after it has been phosphorylated. However, the details of the interactions between Knl1, Bub1 and Bub3 are not understood, and it is not clear whether these interactions are essential for the SAC. Now Primorac et al. have shown that Bub3 binds directly to Knl1 through a region that contains multiple MELT motifs (where M, E, L and T are all amino acids), and that this interaction only happens if these ‘MELT repeats’ have been phosphorylated. Moreover, once bound to the Knl1, Bub3 then recruits Bub1 to the kinetochore. By showing that the recognition of phosphorylated Knl1 by the Bub1-Bub3 complex has a central role in the spindle assembly checkpoint, these results highlight the importance of phosphorylation as a way of regulating the timing of events during the cell cycle. DOI:http://dx.doi.org/10.7554/eLife.01030.002
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Affiliation(s)
- Ivana Primorac
- Department of Mechanistic Cell Biology , Max Planck Institute of Molecular Physiology , Dortmund , Germany
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31
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Kumar S, Jordan MC, Datla R, Cloutier S. The LuWD40-1 gene encoding WD repeat protein regulates growth and pollen viability in flax (Linum Usitatissimum L.). PLoS One 2013; 8:e69124. [PMID: 23935935 PMCID: PMC3728291 DOI: 10.1371/journal.pone.0069124] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/11/2013] [Indexed: 01/22/2023] Open
Abstract
As a crop, flax holds significant commercial value for its omega-3 rich oilseeds and stem fibres. Canada is the largest producer of linseed but there exists scope for significant yield improvements. Implementation of mechanisms such as male sterility can permit the development of hybrids to assist in achieving this goal. Temperature sensitive male sterility has been reported in flax but the leakiness of this system in field conditions limits the production of quality hybrid seeds. Here, we characterized a 2,588 bp transcript differentially expressed in male sterile lines of flax. The twelve intron gene predicted to encode a 368 amino acid protein has five WD40 repeats which, in silico, form a propeller structure with putative nucleic acid and histone binding capabilities. The LuWD40-1 protein localized to the nucleus and its expression increased during the transition and continued through the vegetative stages (seed, etiolated seedling, stem) while the transcript levels declined during reproductive development (ovary, anthers) and embryonic morphogenesis of male fertile plants. Knockout lines for LuWD40-1 in flax failed to develop shoots while overexpression lines showed delayed growth phenotype and were male sterile. The non-viable flowers failed to open and the pollen grains from these flowers were empty. Three independent transgenic lines overexpressing the LuWD40-1 gene had ∼80% non-viable pollen, reduced branching, delayed flowering and maturity compared to male fertile genotypes. The present study provides new insights into a male sterility mechanism present in flax.
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Affiliation(s)
- Santosh Kumar
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
- Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada
| | - Mark C. Jordan
- Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada
| | - Raju Datla
- National Research Council, Saskatoon, Saskatchewan, Canada
| | - Sylvie Cloutier
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
- Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada
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32
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Ibrahim B, Henze R, Gruenert G, Egbert M, Huwald J, Dittrich P. Spatial rule-based modeling: a method and its application to the human mitotic kinetochore. Cells 2013; 2:506-44. [PMID: 24709796 PMCID: PMC3972674 DOI: 10.3390/cells2030506] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/05/2013] [Accepted: 06/25/2013] [Indexed: 12/23/2022] Open
Abstract
A common problem in the analysis of biological systems is the combinatorial explosion that emerges from the complexity of multi-protein assemblies. Conventional formalisms, like differential equations, Boolean networks and Bayesian networks, are unsuitable for dealing with the combinatorial explosion, because they are designed for a restricted state space with fixed dimensionality. To overcome this problem, the rule-based modeling language, BioNetGen, and the spatial extension, SRSim, have been developed. Here, we describe how to apply rule-based modeling to integrate experimental data from different sources into a single spatial simulation model and how to analyze the output of that model. The starting point for this approach can be a combination of molecular interaction data, reaction network data, proximities, binding and diffusion kinetics and molecular geometries at different levels of detail. We describe the technique and then use it to construct a model of the human mitotic inner and outer kinetochore, including the spindle assembly checkpoint signaling pathway. This allows us to demonstrate the utility of the procedure, show how a novel perspective for understanding such complex systems becomes accessible and elaborate on challenges that arise in the formulation, simulation and analysis of spatial rule-based models.
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Affiliation(s)
- Bashar Ibrahim
- Bio Systems Analysis Group, Institute of Computer Science, Jena Centre for Bioinformatics and Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, D-0007743 Jena, Germany.
| | - Richard Henze
- Bio Systems Analysis Group, Institute of Computer Science, Jena Centre for Bioinformatics and Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, D-0007743 Jena, Germany.
| | - Gerd Gruenert
- Bio Systems Analysis Group, Institute of Computer Science, Jena Centre for Bioinformatics and Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, D-0007743 Jena, Germany.
| | - Matthew Egbert
- Bio Systems Analysis Group, Institute of Computer Science, Jena Centre for Bioinformatics and Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, D-0007743 Jena, Germany.
| | - Jan Huwald
- Bio Systems Analysis Group, Institute of Computer Science, Jena Centre for Bioinformatics and Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, D-0007743 Jena, Germany.
| | - Peter Dittrich
- Bio Systems Analysis Group, Institute of Computer Science, Jena Centre for Bioinformatics and Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, D-0007743 Jena, Germany.
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33
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Volpi S, Bongiorni S, Fabbretti F, Wakimoto BT, Prantera G. Drosophila rae1 is required for male meiosis and spermatogenesis. J Cell Sci 2013; 126:3541-51. [PMID: 23788425 DOI: 10.1242/jcs.111328] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Previous studies of RAE1, a conserved WD40 protein, in Schizosaccharomyces pombe and mouse revealed a role in mRNA export and cell cycle progression in mitotic cells. Studies of RAE1 in Drosophila showed that the protein localizes to the nuclear envelope and is required for progression through the G1 phase of the cell cycle but not RNA export in tissue culture cells. Drosophila RAE1 also plays an essential developmental role, as it is required for viability and synaptic growth regulation as a component of an E3 ubiquitin ligase complex. Here we describe characterization of a new Drosophila rae1 mutant that is viable but results in male sterility. The mutant showed striking defects in primary spermatocyte nuclear integrity, meiotic chromosome condensation, segregation, and spindle morphology. These defects led to a failure to complete meiosis but allowed several aspects of spermatid differentiation to proceed, including axoneme formation and elongation. A GFP-RAE1 fusion protein that rescued most of the cytological defects showed a dynamic localization to the nuclear envelope, chromatin and other structures depending on the stage of spermatogenesis. A role for RAE1 in male meiosis, as well as mitotic cells, was also indicated by the defects induced by expression of rae1-RNAi. These studies in Drosophila provide the first evidence for an essential meiotic role of RAE1, and thus define RAE1 as a protein required for both meiotic and mitotic cell cycles.
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Affiliation(s)
- Silvia Volpi
- Department of Ecology and Biology, University of Tuscia, Viterbo, Italy
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34
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Karess RE, Wassmann K, Rahmani Z. New insights into the role of BubR1 in mitosis and beyond. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:223-73. [PMID: 24016527 DOI: 10.1016/b978-0-12-407694-5.00006-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BubR1 is a critical component of the spindle assembly checkpoint, the surveillance mechanism that helps maintain the high fidelity of mitotic chromosome segregation by preventing cells from initiating anaphase if one or more kinetochores are not attached to the spindle. BubR1 also helps promote the establishment of stable kinetochore-microtubule attachments during prometaphase. In this chapter, we review the structure, functions, and regulation of BubR1 in these "classical roles" at the kinetochore. We discuss its recruitment to kinetochores, its assembly into the inhibitor of anaphase progression, and the importance of its posttranslational modifications. We also consider the evidence for its participation in other roles beyond mitosis, such as the meiosis-specific processes of recombination and prophase arrest of the first meiotic division, the cellular response to DNA damage, and in the regulation of centrosome and basal body function. Finally, studies are presented linking BubR1 dysfunction or misregulation to aging and human disease, particularly cancer.
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Affiliation(s)
- Roger E Karess
- Institut Jacques Monod, UMR 7592 CNRS, Université Paris Diderot-Paris 7, Paris, France.
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Ricke RM, Jeganathan KB, Malureanu L, Harrison AM, van Deursen JM. Bub1 kinase activity drives error correction and mitotic checkpoint control but not tumor suppression. ACTA ACUST UNITED AC 2012; 199:931-49. [PMID: 23209306 PMCID: PMC3518220 DOI: 10.1083/jcb.201205115] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mice expressing a version of Bub1 that lacks kinase activity have increased chromosome segregation errors and aneuploidy but not increased susceptibility to tumors. The mitotic checkpoint protein Bub1 is essential for embryogenesis and survival of proliferating cells, and bidirectional deviations from its normal level of expression cause chromosome missegregation, aneuploidy, and cancer predisposition in mice. To provide insight into the physiological significance of this critical mitotic regulator at a modular level, we generated Bub1 mutant mice that lack kinase activity using a knockin gene-targeting approach that preserves normal protein abundance. In this paper, we uncover that Bub1 kinase activity integrates attachment error correction and mitotic checkpoint signaling by controlling the localization and activity of Aurora B kinase through phosphorylation of histone H2A at threonine 121. Strikingly, despite substantial chromosome segregation errors and aneuploidization, mice deficient for Bub1 kinase activity do not exhibit increased susceptibility to spontaneous or carcinogen-induced tumorigenesis. These findings provide a unique example of a modular mitotic activity orchestrating two distinct networks that safeguard against whole chromosome instability and reveal the differential importance of distinct aneuploidy-causing Bub1 defects in tumor suppression.
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Affiliation(s)
- Robin M Ricke
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Ding Y, Hubert CG, Herman J, Corrin P, Toledo CM, Skutt-Kakaria K, Vazquez J, Basom R, Zhang B, Risler JK, Pollard SM, Nam DH, Delrow JJ, Zhu J, Lee J, DeLuca J, Olson JM, Paddison PJ. Cancer-Specific requirement for BUB1B/BUBR1 in human brain tumor isolates and genetically transformed cells. Cancer Discov 2012; 3:198-211. [PMID: 23154965 DOI: 10.1158/2159-8290.cd-12-0353] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
UNLABELLED To identify new candidate therapeutic targets for glioblastoma multiforme, we combined functional genetics and glioblastoma network modeling to identify kinases required for the growth of patient-derived brain tumor-initiating cells (BTIC) but that are dispensable to proliferating human neural stem cells (NSC). This approach yielded BUB1B/BUBR1, a critical mitotic spindle checkpoint player, as the top-scoring glioblastoma lethal kinase. Knockdown of BUB1B inhibited expansion of BTIC isolates, both in vitro and in vivo, without affecting proliferation of NSCs or astrocytes. Mechanistic studies revealed that BUB1B's GLE2p-binding sequence (GLEBS) domain activity is required to suppress lethal kinetochore-microtubule (KT-MT) attachment defects in glioblastoma isolates and genetically transformed cells with altered sister KT dynamics, which likely favor KT-MT instability. These results indicate that glioblastoma tumors have an added requirement for BUB1B to suppress lethal consequences of altered KT function and further suggest that sister KT measurements may predict cancer-specific sensitivity to BUB1B inhibition and perhaps other mitotic targets that affect KT-MT stability. SIGNIFICANCE Currently, no effective therapies are available for glioblastoma, the most frequent and aggressive brain tumor. Our results suggest that targeting the GLEBS domain activity of BUB1B may provide a therapeutic window for glioblastoma, as the GLEBS domain is nonessential in untransformed cells. Moreover, the results further suggest that sister KT distances at metaphase may predict sensitivity to anticancer therapeutics targeting KT function.
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Affiliation(s)
- Yu Ding
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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Complexes of vesicular stomatitis virus matrix protein with host Rae1 and Nup98 involved in inhibition of host transcription. PLoS Pathog 2012; 8:e1002929. [PMID: 23028327 PMCID: PMC3460625 DOI: 10.1371/journal.ppat.1002929] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 08/13/2012] [Indexed: 11/19/2022] Open
Abstract
Vesicular stomatitis virus (VSV) suppresses antiviral responses in infected cells by inhibiting host gene expression at multiple levels, including transcription, nuclear cytoplasmic transport, and translation. The inhibition of host gene expression is due to the activity of the viral matrix (M) protein. Previous studies have shown that M protein interacts with host proteins Rae1 and Nup98 that have been implicated in regulating nuclear-cytoplasmic transport. However, Rae1 function is not essential for host mRNA transport, raising the question of how interaction of a viral protein with a host protein that is not essential for gene expression causes a global inhibition at multiple levels. We tested the hypothesis that there may be multiple M protein-Rae1 complexes involved in inhibiting host gene expression at multiple levels. Using size exclusion chromatography and sedimentation velocity analysis, it was determined that Rae1 exists in high, intermediate, and low molecular weight complexes. The intermediate molecular weight complexes containing Nup98 interacted most efficiently with M protein. The low molecular weight form also interacted with M protein in cells that overexpress Rae1 or cells in which Nup98 expression was silenced. Silencing Rae1 expression had little if any effect on nuclear accumulation of host mRNA in VSV-infected cells, nor did it affect VSV's ability to inhibit host translation. Instead, silencing Rae1 expression reduced the ability of VSV to inhibit host transcription. M protein interacted efficiently with Rae1-Nup98 complexes associated with the chromatin fraction of host nuclei, consistent with an effect on host transcription. These results support the idea that M protein-Rae1 complexes serve as platforms to promote the interaction of M protein with other factors involved in host transcription. They also support the idea that Rae1-Nup98 complexes play a previously under-appreciated role in regulation of transcription. All viruses have mechanisms to suppress or evade host antiviral responses. These mechanisms are critical for viral pathogenicity. Vesicular stomatitis virus (VSV) suppresses antiviral responses by global inhibition of host gene expression mediated by the viral matrix (M) protein. M protein interacts with the host protein Rae1 in a complex with the nucleoporin Nup98. It had been thought that interaction of M protein with Rae1 blocks nuclear-cytoplasmic mRNA transport. However, other data show that Rae1 is not essential for mRNA transport. With this discrepancy in mind, we re-examined the interaction of M protein with Rae1 and Nup98 and the level of host gene expression in which they are involved. A key result was that silencing Rae1 expression did not affect host gene expression, but instead increased cellular resistance to inhibition by M protein. Furthermore, silencing Rae1 expression primarily affected the inhibition of host transcription with no significant effect on nuclear accumulation of mRNA. These results support a model in which Rae1 serves as a “platform” to promote interaction of M protein with cellular targets involved in host transcription. This illustrates a general principle that viral proteins can have multiple cellular effects by interacting with host proteins that are themselves multi-functional.
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González-Aguilera C, Askjaer P. Dissecting the NUP107 complex: multiple components and even more functions. Nucleus 2012; 3:340-8. [PMID: 22713280 DOI: 10.4161/nucl.21135] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Nuclear Pore Complex (NPC) is a fascinating structure whose functional relevance and complexity attract significant interest. Within the NPC, several different subcomplexes interact with each other to form a highly conserved and stable structure. One of these subcomplexes is the NUP107 complex, constituted by 7-9 members. A wide variety of functions have been ascribed to the NUP107 complex, ranging from NPC assembly to mRNA export to cell differentiation. Recently, genetic dissection of the NUP107 complex has provided novel insight to the assembly of the complex and has, moreover, revealed an unexpected connection with the mitotic spindle assembly checkpoint protein MAD1.
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Affiliation(s)
- Cristina González-Aguilera
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide, Seville, Spain
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RAE-1, a novel PHR binding protein, is required for axon termination and synapse formation in Caenorhabditis elegans. J Neurosci 2012; 32:2628-36. [PMID: 22357847 DOI: 10.1523/jneurosci.2901-11.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Previous studies in Caenorhabditis elegans showed that RPM-1 (Regulator of Presynaptic Morphology-1) regulates axon termination and synapse formation. To understand the mechanism of how rpm-1 functions, we have used mass spectrometry to identify RPM-1 binding proteins, and have identified RAE-1 (RNA Export protein-1) as an evolutionarily conserved binding partner. We define a RAE-1 binding region in RPM-1, and show that this binding interaction is conserved and also occurs between Rae1 and the human ortholog of RPM-1 called Pam (protein associated with Myc). rae-1 loss of function causes similar axon and synapse defects, and synergizes genetically with two other RPM-1 binding proteins, GLO-4 and FSN-1. Further, we show that RAE-1 colocalizes with RPM-1 in neurons, and that rae-1 functions downstream of rpm-1. These studies establish a novel postmitotic function for rae-1 in neuronal development.
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Yeh PC, Yeh CC, Chen YC, Juang YL. RED, a spindle pole-associated protein, is required for kinetochore localization of MAD1, mitotic progression, and activation of the spindle assembly checkpoint. J Biol Chem 2012; 287:11704-16. [PMID: 22351768 DOI: 10.1074/jbc.m111.299131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The spindle assembly checkpoint (SAC) is essential for ensuring the proper attachment of kinetochores to the spindle and, thus, the precise separation of paired sister chromatids during mitosis. The SAC proteins are recruited to the unattached kinetochores for activation of the SAC in prometaphase. However, it has been less studied whether activation of the SAC also requires the proteins that do not localize to the kinetochores. Here, we show that the nuclear protein RED, also called IK, a down-regulator of human leukocyte antigen (HLA) II, interacts with the human SAC protein MAD1. Two RED-interacting regions identified in MAD1 are from amino acid residues 301-340 and 439-480, designated as MAD1(301-340) and MAD1(439-480), respectively. Our observations reveal that RED is a spindle pole-associated protein that colocalizes with MAD1 at the spindle poles in metaphase and anaphase. Depletion of RED can cause a shorter mitotic timing, a failure in the kinetochore localization of MAD1 in prometaphase, and a defect in the SAC. Furthermore, the RED-interacting peptides MAD1(301-340) and MAD1(439-480), fused to enhanced green fluorescence protein, can colocalize with RED at the spindle poles in prometaphase, and their expression can abrogate the SAC. Taken together, we conclude that RED is required for kinetochore localization of MAD1, mitotic progression, and activation of the SAC.
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Affiliation(s)
- Pei-Chi Yeh
- Institute of Medical Sciences, Tzu-Chi University, Hualien 97004, Taiwan
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Krenn V, Wehenkel A, Li X, Santaguida S, Musacchio A. Structural analysis reveals features of the spindle checkpoint kinase Bub1-kinetochore subunit Knl1 interaction. ACTA ACUST UNITED AC 2012; 196:451-67. [PMID: 22331848 PMCID: PMC3283998 DOI: 10.1083/jcb.201110013] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The function of the essential checkpoint kinases Bub1 and BubR1 requires their recruitment to mitotic kinetochores. Kinetochore recruitment of Bub1 and BubR1 is proposed to rely on the interaction of the tetratricopeptide repeats (TPRs) of Bub1 and BubR1 with two KI motifs in the outer kinetochore protein Knl1. We determined the crystal structure of the Bub1 TPRs in complex with the cognate Knl1 KI motif and compared it with the structure of the equivalent BubR1TPR-KI motif complex. The interaction developed along the convex surface of the TPR assembly. Point mutations on this surface impaired the interaction of Bub1 and BubR1 with Knl1 in vitro and in vivo but did not cause significant displacement of Bub1 and BubR1 from kinetochores. Conversely, a 62-residue segment of Bub1 that includes a binding domain for the checkpoint protein Bub3 and is C terminal to the TPRs was necessary and largely sufficient for kinetochore recruitment of Bub1. These results shed light on the determinants of kinetochore recruitment of Bub1.
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Affiliation(s)
- Veronica Krenn
- Department of Experimental Oncology, European Institute of Oncology, 20139 Milan, Italy
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42
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Lara-Gonzalez P, Scott MIF, Diez M, Sen O, Taylor SS. BubR1 blocks substrate recruitment to the APC/C in a KEN-box-dependent manner. J Cell Sci 2011; 124:4332-45. [PMID: 22193957 DOI: 10.1242/jcs.094763] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The spindle assembly checkpoint (SAC) is a signalling network that delays anaphase onset until all the chromosomes are attached to the mitotic spindle through their kinetochores. The downstream target of the spindle checkpoint is the anaphase-promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase that targets several anaphase inhibitors for proteolysis, including securin and cyclin B1. In the presence of unattached kinetochores, the APC/C is inhibited by the mitotic checkpoint complex (MCC), a tetrameric complex composed of three SAC components, namely BubR1, Bub3 and Mad2, and the APC/C co-activator Cdc20. The molecular mechanisms underlying exactly how unattached kinetochores catalyse MCC formation and how the MCC then inhibits the APC/C remain obscure. Here, using RNAi complementation and in vitro ubiquitylation assays, we investigate the domains in BubR1 required for APC/C inhibition. We observe that kinetochore localisation of BubR1 is required for efficient MCC assembly and SAC response. Furthermore, in contrast to previous studies, we show that the N-terminal domain of BubR1 is the only domain involved in binding to Cdc20-Mad2 and the APC/C. Within this region, an N-terminal KEN box (KEN1) is essential for these interactions. By contrast, mutation of the second KEN box (KEN2) of BubR1 does not interfere with MCC assembly or APC/C binding. However, both in cells and in vitro, the KEN2 box is required for inhibition of APC/C when activated by Cdc20 (APC/C(Cdc20)). Indeed, we show that this second KEN box promotes SAC function by blocking the recruitment of substrates to the APC/C. Thus, we propose a model in which the BubR1 KEN boxes play two very different roles, the first to promote MCC assembly and the second to block substrate recruitment to APC/C(Cdc20).
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Affiliation(s)
- Pablo Lara-Gonzalez
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
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Chatel G, Fahrenkrog B. Nucleoporins: leaving the nuclear pore complex for a successful mitosis. Cell Signal 2011; 23:1555-62. [PMID: 21683138 DOI: 10.1016/j.cellsig.2011.05.023] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 05/31/2011] [Indexed: 12/01/2022]
Abstract
The nuclear envelope (NE) separates the cytoplasm and the cell nucleus of interphase eukaryotic cells and nuclear pore complexes (NPCs) mediate the macromolecular exchange between these two compartments. The NE and the NPCs of vertebrate cells disassemble during prophase and the nuclear pore proteins (nucleoporins) are distributed within the mitotic cytoplasm. For an increasing number of them active mitotic functions have been assigned over the past few years. Nucleoporins are participating in spindle assembly, kinetochore organisation, and the spindle assembly checkpoint, all processes that control chromosome segregation and are important for maintenance of genome integrity. But nucleoporins are also engaged in early and late mitotic events, such as centrosome positioning and cytokinesis. Here we will highlight recent progress in deciphering the roles for nucleoporins in the distinct steps of mitosis.
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Affiliation(s)
- Guillaume Chatel
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Belgium
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44
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Yung E, Sekulovic S, Argiropoulos B, Lai CK, Leung M, Berg T, Vollett S, Chang VCD, Wan A, Wong S, Humphries RK. Delineating domains and functions of NUP98 contributing to the leukemogenic activity of NUP98-HOX fusions. Leuk Res 2010; 35:545-50. [PMID: 21130494 DOI: 10.1016/j.leukres.2010.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 10/06/2010] [Accepted: 10/08/2010] [Indexed: 11/30/2022]
Abstract
To determine the contribution of the common N-terminal truncation of NUP98 in NUP98-translocations resulting in acute myeloid leukemia, we have conducted a structure-function analysis of NUP98 in the context of NUP98-HOXA10HD, a novel, canonical NUP98-Hox fusion that significantly enhances the self-renewal capacity of hematopoietic stem cells and collaborates with Meis1 to induce AML in our mouse models. Our results identify that NUP98 functions by transcriptional activation likely by recruitment of CBP/p300 via its FG/GLFG repeats. In contrast, the functional interaction of NUP98 with Rae1 or the anaphase promoting complex appears non-essential for its role in NUP98-leukemogenic fusions.
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Affiliation(s)
- Eric Yung
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, Canada
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Nakaya T, Kuwahara K, Ohta K, Kitabatake M, Toda T, Takeda N, Tani T, Kondo E, Sakaguchi N. Critical Role of Pcid2 in B Cell Survival through the Regulation of MAD2 Expression. THE JOURNAL OF IMMUNOLOGY 2010; 185:5180-7. [DOI: 10.4049/jimmunol.1002026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Fung TK, Chung MIS, Liang R, Leung AYH. Role of a novel zebrafish nup98 during embryonic development. Exp Hematol 2010; 38:1014-1021.e1-2. [PMID: 20696206 DOI: 10.1016/j.exphem.2010.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 07/23/2010] [Accepted: 07/27/2010] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The nucleoporin NUP98 is a component of the nuclear pore complex that regulates nucleocytoplasmic trafficking. It has been characterized in acute myeloid leukemia as a fusion partner during chromosomal translocation. In this study, we identified a zebrafish nup98 gene and examined its role in embryonic development. MATERIALS AND METHODS Two expressed sequence tags with translated sequences homologous to human NUP98 were identified. The gene was cloned by polymerase chain reaction from complementary DNA of zebrafish embryos. Cellular functions of zebrafish NUP98 were investigated in HeLa cells. nup98 expression and developmental functions in zebrafish embryos were investigated by whole-mount in situ hybridization and morpholino knockdown. RESULTS Protein sequence of zebrafish nup98 shared 65% identity with its human homolog. Ectopic expression of zebrafish nup98 rescued the defective messenger RNA export due to human NUP98 knockdown in HeLa cells. In zebrafish embryos, nup98 was expressed diffusely in eyes and the developing brain since 18 hours postfertilization. Knockdown of nup98 with morpholino upregulated pu.1 expression by 39% ± 15% (p = 0.0153) and scl expression by 36% ± 7.6% (p = 0.0017). Expression of genes associated with erythropoiesis was unchanged. The morphants also developed intracranial hemorrhage at 48 hours postfertilization due to defective blood vessel development. CONCLUSIONS A novel zebrafish nup98 was identified and it serves a role in nucleocytoplasmic trafficking similar to human NUP98. During development, it modulates hematopoietic stem cell and early myeloid development and maintains the integrity of cranial vasculature in the developing central nervous system.
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Affiliation(s)
- Tsz-Kan Fung
- Department of Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong
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47
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Structural and functional analysis of the interaction between the nucleoporin Nup98 and the mRNA export factor Rae1. Proc Natl Acad Sci U S A 2010; 107:10406-11. [PMID: 20498086 DOI: 10.1073/pnas.1005389107] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The export of mRNAs is a multistep process, involving the packaging of mRNAs into messenger ribonucleoprotein particles (mRNPs), their transport through nuclear pore complexes, and mRNP remodeling events prior to translation. Ribonucleic acid export 1 (Rae1) and Nup98 are evolutionarily conserved mRNA export factors that are targeted by the vesicular stomatitis virus matrix protein to inhibit host cell nuclear export. Here, we present the crystal structure of human Rae1 in complex with the Gle2-binding sequence (GLEBS) of Nup98 at 1.65 A resolution. Rae1 forms a seven-bladed beta-propeller with several extensive surface loops. The Nup98 GLEBS motif forms an approximately 50-A-long hairpin that binds with its C-terminal arm to an essentially invariant hydrophobic surface that extends over the entire top face of the Rae1 beta-propeller. The C-terminal arm of the GLEBS hairpin is necessary and sufficient for Rae1 binding, and we identify a tandem glutamate element in this arm as critical for complex formation. The Rae1*Nup98(GLEBS) surface features an additional conserved patch with a positive electrostatic potential, and we demonstrate that the complex possesses single-stranded RNA-binding capability. Together, these data suggest that the Rae1*Nup98 complex directly binds to the mRNP at several stages of the mRNA export pathway.
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D'Arcy S, Davies OR, Blundell TL, Bolanos-Garcia VM. Defining the molecular basis of BubR1 kinetochore interactions and APC/C-CDC20 inhibition. J Biol Chem 2010; 285:14764-76. [PMID: 20220147 PMCID: PMC2863239 DOI: 10.1074/jbc.m109.082016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 02/26/2010] [Indexed: 11/06/2022] Open
Abstract
BubR1 is essential for the mitotic checkpoint that prevents aneuploidy in cellular progeny by triggering anaphase delay in response to kinetochores incorrectly/not attached to the mitotic spindle. Here, we define the molecular architecture of the functionally significant N-terminal region of human BubR1 and present the 1.8 A crystal structure of its tetratricopeptide repeat (TPR) domain. The structure reveals divergence from the classical TPR fold and is highly similar to the TPR domain of budding yeast Bub1. Shared distinctive features include a disordered loop insertion, a 3(10)-helix, a tight turn involving glycine positive Phi angles, and noncanonical packing of and between the TPR motifs. We also define the molecular determinants of the interaction between BubR1 and kinetochore protein Blinkin. We identify a shallow groove on the concave surface of the BubR1 TPR domain that forms multiple discrete and potentially cooperative interactions with Blinkin. Finally, we present evidence for a direct interaction between BubR1 and Bub1 mediated by regions C-terminal to their TPR domains. This interaction provides a mechanism for Bub1-dependent kinetochore recruitment of BubR1. We thus present novel molecular insights into the structure of BubR1 and its interactions at the kinetochore-microtubule interface. Our studies pave the way for future structure-directed engineering aimed at dissecting the roles of kinetochore-bound and other pools of BubR1 in vivo.
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Affiliation(s)
- Sheena D'Arcy
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom and
| | - Owen R. Davies
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom and
- the Medical Research Council Centre for Regenerative Medicine, Institute for Stem Cell Research, University of Edinburgh, Edinburgh EH9 3JQ, Scotland, United Kingdom
| | - Tom L. Blundell
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom and
| | - Victor M. Bolanos-Garcia
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom and
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Vanoosthuyse V, Meadows JC, van der Sar SJA, Millar JBA, Hardwick KG. Bub3p facilitates spindle checkpoint silencing in fission yeast. Mol Biol Cell 2010; 20:5096-105. [PMID: 19846658 DOI: 10.1091/mbc.e09-09-0762] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Although critical for spindle checkpoint signaling, the role kinetochores play in anaphase promoting complex (APC) inhibition remains unclear. Here we show that spindle checkpoint proteins are severely depleted from unattached kinetochores in fission yeast cells lacking Bub3p. Surprisingly, a robust mitotic arrest is maintained in the majority of bub3 Delta cells, yet they die, suggesting that Bub3p is essential for successful checkpoint recovery. During recovery, two defects are observed: (1) cells mis-segregate chromosomes and (2) anaphase onset is significantly delayed. We show that Bub3p is required to activate the APC upon inhibition of Aurora kinase activity in checkpoint-arrested cells, suggesting that Bub3p is required for efficient checkpoint silencing downstream of Aurora kinase. Together, these results suggest that spindle checkpoint signals can be amplified in the nucleoplasm, yet kinetochore localization of spindle checkpoint components is required for proper recovery from a spindle checkpoint-dependent arrest.
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Affiliation(s)
- Vincent Vanoosthuyse
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, EH9 3JR, United Kingdom.
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50
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Niikura Y, Ogi H, Kikuchi K, Kitagawa K. BUB3 that dissociates from BUB1 activates caspase-independent mitotic death (CIMD). Cell Death Differ 2010; 17:1011-24. [PMID: 20057499 DOI: 10.1038/cdd.2009.207] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The cell death mechanism that prevents aneuploidy caused by a failure of the spindle checkpoint has recently emerged as an important regulatory paradigm. We previously identified a new type of mitotic cell death, termed caspase-independent mitotic death (CIMD), which is induced during early mitosis by partial BUB1 (a spindle checkpoint protein) depletion and defects in kinetochore-microtubule attachment. In this study, we have shown that survived cells that escape CIMD have abnormal nuclei, and we have determined the molecular mechanism by which BUB1 depletion activates CIMD. The BUB3 protein (a BUB1 interactor and a spindle checkpoint protein) interacts with p73 (a homolog of p53), specifically in cells wherein CIMD occurs. The BUB3 protein that is freed from BUB1 associates with p73 on which Y99 is phosphorylated by c-Abl tyrosine kinase, resulting in the activation of CIMD. These results strongly support the hypothesis that CIMD is the cell death mechanism protecting cells from aneuploidy by inducing the death of cells prone to substantial chromosome missegregation.
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Affiliation(s)
- Y Niikura
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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