1
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Lima JT, Pereira AJ, Ferreira JG. The LINC complex ensures accurate centrosome positioning during prophase. Life Sci Alliance 2024; 7:e202302404. [PMID: 38228373 DOI: 10.26508/lsa.202302404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/18/2024] Open
Abstract
Accurate centrosome separation and positioning during early mitosis relies on force-generating mechanisms regulated by a combination of extracellular, cytoplasmic, and nuclear cues. The identity of the nuclear cues involved in this process remains largely unknown. Here, we investigate how the prophase nucleus contributes to centrosome positioning during the initial stages of mitosis, using a combination of cell micropatterning, high-resolution live-cell imaging, and quantitative 3D cellular reconstruction. We show that in untransformed RPE-1 cells, centrosome positioning is regulated by a nuclear signal, independently of external cues. This nuclear mechanism relies on the linker of nucleoskeleton and cytoskeleton complex that controls the timely loading of dynein on the nuclear envelope (NE), providing spatial cues for robust centrosome positioning on the shortest nuclear axis, before nuclear envelope permeabilization. Our results demonstrate how nuclear-cytoskeletal coupling maintains a robust centrosome positioning mechanism to ensure efficient mitotic spindle assembly.
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Affiliation(s)
- Joana T Lima
- https://ror.org/04wjk1035 Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
- Departamento de Biomedicina, Faculdade de Medicina do Porto, Unidade de Biologia Experimental, Porto, Portugal
- https://ror.org/04wjk1035 Programa Doutoral em Biomedicina, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - António J Pereira
- https://ror.org/04wjk1035 Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
| | - Jorge G Ferreira
- https://ror.org/04wjk1035 Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
- Departamento de Biomedicina, Faculdade de Medicina do Porto, Unidade de Biologia Experimental, Porto, Portugal
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2
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Li X, Bloomfield M, Bridgeland A, Cimini D, Chen J. A fine balance among key biophysical factors is required for recovery of bipolar mitotic spindle from monopolar and multipolar abnormalities. Mol Biol Cell 2023; 34:ar90. [PMID: 37342878 PMCID: PMC10398891 DOI: 10.1091/mbc.e22-10-0485] [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: 11/02/2022] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 06/23/2023] Open
Abstract
During mitosis, equal partitioning of chromosomes into two daughter cells requires assembly of a bipolar mitotic spindle. Because the spindle poles are each organized by a centrosome in animal cells, centrosome defects can lead to monopolar or multipolar spindles. However, the cell can effectively recover the bipolar spindle by separating the centrosomes in monopolar spindles and clustering them in multipolar spindles. To interrogate how a cell can separate and cluster centrosomes as needed to form a bipolar spindle, we developed a biophysical model, based on experimental data, which uses effective potential energies to describe key mechanical forces driving centrosome movements during spindle assembly. Our model identified general biophysical factors crucial for robust bipolarization of spindles that start as monopolar or multipolar. These factors include appropriate force fluctuation between centrosomes, balance between repulsive and attractive forces between centrosomes, exclusion of the centrosomes from the cell center, proper cell size and geometry, and a limited centrosome number. Consistently, we found experimentally that bipolar centrosome clustering is promoted as mitotic cell aspect ratio and volume decrease in tetraploid cancer cells. Our model provides mechanistic explanations for many more experimental phenomena and a useful theoretical framework for future studies of spindle assembly.
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Affiliation(s)
- Xiaochu Li
- Department of Biological Sciences, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
- BIOTRANS Graduate Program, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
| | - Mathew Bloomfield
- Department of Biological Sciences, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
- Fralin Life Sciences Institute, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
| | - Alexandra Bridgeland
- Fralin Life Sciences Institute, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
- Systems Biology Program, College of Science, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
| | - Daniela Cimini
- Department of Biological Sciences, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
- Fralin Life Sciences Institute, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
| | - Jing Chen
- Department of Biological Sciences, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
- Fralin Life Sciences Institute, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
- Center for Soft Matter and Biological Physics, Virginia Tech, Virginia Tech, Blacksburg, VA 24061
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3
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Lodde V, Garcia Barros R, Terzaghi L, Franciosi F, Luciano AM. Insights on the Role of PGRMC1 in Mitotic and Meiotic Cell Division. Cancers (Basel) 2022; 14:cancers14235755. [PMID: 36497237 PMCID: PMC9736406 DOI: 10.3390/cancers14235755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022] Open
Abstract
During mitosis, chromosome missegregation and cytokinesis defects have been recognized as hallmarks of cancer cells. Cytoskeletal elements composing the spindle and the contractile ring and their associated proteins play crucial roles in the faithful progression of mitotic cell division. The hypothesis that PGRMC1, most likely as a part of a yet-to-be-defined complex, is involved in the regulation of spindle function and, more broadly, the cytoskeletal machinery driving cell division is particularly appealing. Nevertheless, more than ten years after the preliminary observation that PGRMC1 changes its localization dynamically during meiotic and mitotic cell division, this field of research has remained a niche and needs to be fully explored. To encourage research in this fascinating field, in this review, we will recap the current knowledge on PGRMC1 function during mitotic and meiotic cell division, critically highlighting the strengths and limitations of the experimental approaches used so far. We will focus on known interacting partners as well as new putative associated proteins that have recently arisen in the literature and that might support current as well as new hypotheses of a role for PGRMC1 in specific spindle subcompartments, such as the centrosome, kinetochores, and the midzone/midbody.
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4
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Dantas M, Lima JT, Ferreira JG. Nucleus-Cytoskeleton Crosstalk During Mitotic Entry. Front Cell Dev Biol 2021; 9:649899. [PMID: 33816500 PMCID: PMC8014196 DOI: 10.3389/fcell.2021.649899] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/26/2021] [Indexed: 12/30/2022] Open
Abstract
In preparation for mitosis, cells undergo extensive reorganization of the cytoskeleton and nucleus, so that chromosomes can be efficiently segregated into two daughter cells. Coordination of these cytoskeletal and nuclear events occurs through biochemical regulatory pathways, orchestrated by Cyclin-CDK activity. However, recent studies provide evidence that physical forces are also involved in the early steps of spindle assembly. Here, we will review how the crosstalk of physical forces and biochemical signals coordinates nuclear and cytoplasmic events during the G2-M transition, to ensure efficient spindle assembly and faithful chromosome segregation.
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Affiliation(s)
- Margarida Dantas
- Instituto de Investigação e Inovação em Saúde - i3S, University of Porto, Porto, Portugal.,BiotechHealth Ph.D. Programme, University of Porto, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Joana T Lima
- Instituto de Investigação e Inovação em Saúde - i3S, University of Porto, Porto, Portugal.,Departamento de Biomedicina, Faculdade de Medicina, University of Porto, Porto, Portugal
| | - Jorge G Ferreira
- Instituto de Investigação e Inovação em Saúde - i3S, University of Porto, Porto, Portugal.,Departamento de Biomedicina, Faculdade de Medicina, University of Porto, Porto, Portugal
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5
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Nunes V, Ferreira JG. From the cytoskeleton to the nucleus: An integrated view on early spindle assembly. Semin Cell Dev Biol 2021; 117:42-51. [PMID: 33726956 DOI: 10.1016/j.semcdb.2021.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 12/01/2022]
Abstract
Accurate chromosome segregation requires a complete restructuring of cellular organization. Microtubules remodel to assemble a mitotic spindle and the actin cytoskeleton rearranges to form a stiff actomyosin cortex. These cytoplasmic events must be spatially and temporally coordinated with mitotic chromosome condensation and nuclear envelope permeabilization, in order to ensure mitotic timing and fidelity. Here, we discuss the main cytoskeletal and nuclear events that occur during mitotic entry in proliferating animal cells, focusing on their coordinated contribution for early mitotic spindle assembly. We will also explore recent progress in understanding their regulatory biochemical and mechanical pathways.
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Affiliation(s)
- Vanessa Nunes
- Instituto de Investigação e Inovação em Saúde - i3S, University of Porto, Porto, Portugal; BiotechHealth PhD Programe, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Jorge G Ferreira
- Instituto de Investigação e Inovação em Saúde - i3S, University of Porto, Porto, Portugal; Departamento de Biomedicina, Faculdade de Medicina, University of Porto, Porto, Portugal.
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6
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Hoffmann I. Centrosomes in mitotic spindle assembly and orientation. Curr Opin Struct Biol 2020; 66:193-198. [PMID: 33296732 DOI: 10.1016/j.sbi.2020.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/30/2020] [Accepted: 11/02/2020] [Indexed: 12/24/2022]
Abstract
The centrosome is present in most animal cells and functions as the major microtubule-organizing center to ensure faithful chromosome segregation during cell division. As cells transition from interphase to mitosis, the duplicated centrosomes separate and move to opposite sides of the cell where the spindle assembles. Centrosomes not only nucleate but also organize microtubules of the mitotic spindle. The mitotic spindle is anchored to the cell cortex by the astral microtubules emanating from the centrosomes. Proper orientation of the mitotic spindle is essential for correct cell division. Centrosome-localized polo-like kinase Plk1 has been linked to regulation of proper spindle orientation. A number of proteins including MISP and NuMA have been implicated in the Plk1-mediated spindle orientation pathway.
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Affiliation(s)
- Ingrid Hoffmann
- Cell Cycle Control and Carcinogenesis, German Cancer Research Center, F045, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.
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7
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Nunes V, Dantas M, Castro D, Vitiello E, Wang I, Carpi N, Balland M, Piel M, Aguiar P, Maiato H, Ferreira JG. Centrosome-nuclear axis repositioning drives the assembly of a bipolar spindle scaffold to ensure mitotic fidelity. Mol Biol Cell 2020; 31:1675-1690. [PMID: 32348198 PMCID: PMC7521851 DOI: 10.1091/mbc.e20-01-0047] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
During the initial stages of cell division, the cytoskeleton is extensively reorganized so that a bipolar mitotic spindle can be correctly assembled. This process occurs through the action of molecular motors, cytoskeletal networks, and the nucleus. How the combined activity of these different components is spatiotemporally regulated to ensure efficient spindle assembly remains unclear. To investigate how cell shape, cytoskeletal organization, and molecular motors cross-talk to regulate initial spindle assembly, we use a combination of micropatterning with high-resolution imaging and 3D cellular reconstruction. We show that during prophase, centrosomes and nucleus reorient so that centrosomes are positioned on the shortest nuclear axis at nuclear envelope (NE) breakdown. We also find that this orientation depends on a combination of centrosome movement controlled by Arp2/3-mediated regulation of microtubule dynamics and Dynein-generated forces on the NE that regulate nuclear reorientation. Finally, we observe this centrosome configuration favors the establishment of an initial bipolar spindle scaffold, facilitating chromosome capture and accurate segregation, without compromising division plane orientation.
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Affiliation(s)
- Vanessa Nunes
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135 Porto, Portugal.,Instituto de Biologia Celular e Molecular (IBMC), 4200-135 Porto, Portugal.,BiotechHealth PhD program, Instituto de Ciências Biomédicas (ICBAS), 4050-313 Porto, Portugal
| | - Margarida Dantas
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135 Porto, Portugal.,Instituto de Biologia Celular e Molecular (IBMC), 4200-135 Porto, Portugal.,BiotechHealth PhD program, Instituto de Ciências Biomédicas (ICBAS), 4050-313 Porto, Portugal
| | - Domingos Castro
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135 Porto, Portugal.,Instituto Nacional de Engenharia Biomédica (INEB), 4200-135 Porto, Portugal
| | - Elisa Vitiello
- Laboratoire Interdisciplinaire de Physique, Université Joseph Fourier (Grenoble 1) 38058, France
| | - Irène Wang
- Laboratoire Interdisciplinaire de Physique, Université Joseph Fourier (Grenoble 1) 38058, France
| | - Nicolas Carpi
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France.,Institut Pierre-Gilles de Gennes, PSL Research University, F-75005 Paris, France
| | - Martial Balland
- Laboratoire Interdisciplinaire de Physique, Université Joseph Fourier (Grenoble 1) 38058, France
| | - Matthieu Piel
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France.,Institut Pierre-Gilles de Gennes, PSL Research University, F-75005 Paris, France
| | - Paulo Aguiar
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135 Porto, Portugal.,Instituto Nacional de Engenharia Biomédica (INEB), 4200-135 Porto, Portugal
| | - Helder Maiato
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135 Porto, Portugal.,Instituto de Biologia Celular e Molecular (IBMC), 4200-135 Porto, Portugal.,Departamento de Biomedicina, Faculdade de Medicina do Porto, 4200-450 Porto, Portugal
| | - Jorge G Ferreira
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135 Porto, Portugal.,Instituto de Biologia Celular e Molecular (IBMC), 4200-135 Porto, Portugal.,Departamento de Biomedicina, Faculdade de Medicina do Porto, 4200-450 Porto, Portugal
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8
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Marthiens V, Basto R. Centrosomes: The good and the bad for brain development. Biol Cell 2020; 112:153-172. [PMID: 32170757 DOI: 10.1111/boc.201900090] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/25/2020] [Accepted: 03/01/2020] [Indexed: 12/15/2022]
Abstract
Centrosomes nucleate and organise the microtubule cytoskeleton in animal cells. These membraneless organelles are key structures for tissue organisation, polarity and growth. Centrosome dysfunction, defined as deviation in centrosome numbers and/or structural integrity, has major impact on brain size and functionality, as compared with other tissues of the organism. In this review, we discuss the contribution of centrosomes to brain growth during development. We discuss in particular the impact of centrosome dysfunction in Drosophila and mammalian neural stem cell division and fitness, which ultimately underlie brain growth defects.
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Affiliation(s)
- Véronique Marthiens
- Biology of Centrosomes and Genetic Instability Laboratory, Institut Curie, PSL Research University, CNRS, UMR144, Paris, 75005, France
| | - Renata Basto
- Biology of Centrosomes and Genetic Instability Laboratory, Institut Curie, PSL Research University, CNRS, UMR144, Paris, 75005, France
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9
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Booth AJ, Yue Z, Eykelenboom JK, Stiff T, Luxton GG, Hochegger H, Tanaka TU. Contractile acto-myosin network on nuclear envelope remnants positions human chromosomes for mitosis. eLife 2019; 8:46902. [PMID: 31264963 PMCID: PMC6634967 DOI: 10.7554/elife.46902] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/01/2019] [Indexed: 01/05/2023] Open
Abstract
To ensure proper segregation during mitosis, chromosomes must be efficiently captured by spindle microtubules and subsequently aligned on the mitotic spindle. The efficacy of chromosome interaction with the spindle can be influenced by how widely chromosomes are scattered in space. Here, we quantify chromosome-scattering volume (CSV) and find that it is reduced soon after nuclear envelope breakdown (NEBD) in human cells. The CSV reduction occurs primarily independently of microtubules and is therefore not an outcome of interactions between chromosomes and the spindle. We find that, prior to NEBD, an acto-myosin network is assembled in a LINC complex-dependent manner on the cytoplasmic surface of the nuclear envelope. This acto-myosin network remains on nuclear envelope remnants soon after NEBD, and its myosin-II-mediated contraction reduces CSV and facilitates timely chromosome congression and correct segregation. Thus, we find a novel mechanism that positions chromosomes in early mitosis to ensure efficient and correct chromosome-spindle interactions.
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Affiliation(s)
- Alexander Jr Booth
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Zuojun Yue
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - John K Eykelenboom
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Tom Stiff
- Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Gw Gant Luxton
- College of Biological Sciences, University of Minnesota, Minneapolis, United States
| | - Helfrid Hochegger
- Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Tomoyuki U Tanaka
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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10
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Fritzler MJ, Hudson M, Choi MY, Mahler M, Wang M, Bentow C, Milo J, Baron M. Bicaudal D2 is a novel autoantibody target in systemic sclerosis that shares a key epitope with CENP-A but has a distinct clinical phenotype. Autoimmun Rev 2018; 17:267-275. [PMID: 29369808 DOI: 10.1016/j.autrev.2018.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 11/01/2017] [Indexed: 12/16/2022]
Abstract
We studied the clinical correlations and epitopes of autoantibodies directed to a novel autoantigen, Bicaudal D (BICD2), in systemic sclerosis (SSc) and reviewed its relationship to centromere protein A (CENP-A). 451 SSc sera were tested for anti-BICD2 using a paramagnetic bead immunoassay and then univariate and multivariate logistic regression was used to study the association between anti-BICD2 and demographic and clinical parameters as well as other SSc-related autoantibodies. Epitope mapping was performed on solid phase matrices. 25.7% (116/451) SSc sera were anti-BICD2 positive, of which 19.0% had single specificity anti-BICD2 and 81.0% had other autoantibodies, notably anti-CENP (83/94; 88.3%). Compared to anti-BICD2 negative subjects (335/451), single specificity anti-BICD2 subjects were more likely to have an inflammatory myopathy (IM; 31.8% vs. 9.6%, p=.004) and interstitial lung disease (ILD; 52.4% vs. 29.0%, p=.024). Epitope mapping revealed a serine- and proline-rich nonapeptide SPSPGSSLP comprising amino acids 606-614 of BICD2, shared with CENP-A but not CENP-B. We observed that autoantibodies to BICD2 represent a new biomarker as they were detected in patients without other SSc-specific autoantibodies and were the second most common autoantibody identified in this SSc cohort. Our data indicate that the major cross-reactive epitope is associated with anti-CENP-A but, unlike anti-CENP, single specificity anti-BICD2 antibodies associate with ILD and IM.
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Affiliation(s)
- Marvin J Fritzler
- Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N4N1, Canada.
| | - Marie Hudson
- Department of Medicine, McGill University, Montréal, Quebec, Canada; Division of Rheumatology, Jewish General Hospital, Montréal, Quebec, Canada; Lady Davis Institute, Jewish General Hospital, Montréal, Quebec, Canada.
| | - May Y Choi
- Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N4N1, Canada.
| | - Michael Mahler
- Inova Diagnostics, Division of Research, San Diego, CA, USA.
| | - Mianbo Wang
- Lady Davis Institute, Jewish General Hospital, Montréal, Quebec, Canada.
| | - Chelsea Bentow
- Inova Diagnostics, Division of Research, San Diego, CA, USA.
| | - Jay Milo
- Inova Diagnostics, Division of Research, San Diego, CA, USA.
| | - Murray Baron
- Department of Medicine, McGill University, Montréal, Quebec, Canada; Division of Rheumatology, Jewish General Hospital, Montréal, Quebec, Canada.
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11
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Li YR, Zhong A, Dong H, Ni LH, Tan FQ, Yang WX. Myosin Va plays essential roles in maintaining normal mitosis, enhancing tumor cell motility and viability. Oncotarget 2017; 8:54654-54671. [PMID: 28903372 PMCID: PMC5589611 DOI: 10.18632/oncotarget.17920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 05/03/2017] [Indexed: 12/14/2022] Open
Abstract
Myosin Va, a member of Class V myosin, functions in organelle motility, spindle formation, nuclear morphogenesis and cell motility. The purpose of this study is to explore the expression and localization of myosin Va in testicular cancer and prostate cancer, and its specific roles in tumor progression including cell division, migration and proliferation. We detected myosin Va in testicular and prostate tumor tissues using sqRT-PCR, western blot, and immunofluorescence. Tumor samples showed an increased expression of myosin Va, abnormal actin and myosin Va distribution. Immunofluorescence images during the cell cycle showed that myosin Va tended to gather at cytoplasm during anaphase but co-localized with nucleus during other phases, suggesting the roles of myosin Va in disassembly of spindle microtubule, movement of chromosomes and normal cytokinesis. In addition, multi-nucleation and aberrant nuclear morphology were observed in myosin Va-knockdown cells. Wounding assay and CCK-8-based cell counting were conducted to explore myosin Va roles in cell migration, viability and proliferation. Our results suggest that myosin Va plays essential roles in maintaining normal mitosis, enhancing tumor cell motility and viability, and these properties are the hallmark of tumor progression and metastasis development. Therefore, an increased understanding of myosin Va expression and function will assist in the development of future oncodiagnosis and -therapy.
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Affiliation(s)
- Yan-Ruide Li
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ai Zhong
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Han Dong
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Lu-Han Ni
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Fu-Qing Tan
- The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
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12
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Au FKC, Jia Y, Jiang K, Grigoriev I, Hau BKT, Shen Y, Du S, Akhmanova A, Qi RZ. GAS2L1 Is a Centriole-Associated Protein Required for Centrosome Dynamics and Disjunction. Dev Cell 2016; 40:81-94. [PMID: 28017616 DOI: 10.1016/j.devcel.2016.11.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 10/17/2016] [Accepted: 11/21/2016] [Indexed: 12/16/2022]
Abstract
Mitotic spindle formation and chromosome segregation require timely separation of the two duplicated centrosomes, and this process is initiated in late G2 by centrosome disjunction. Here we report that GAS2L1, a microtubule- and actin-binding protein, associates with the proximal end of mature centrioles and participates in centriole dynamics and centrosome disjunction. GAS2L1 attaches microtubules and actin to centrosomes, and the loss of GAS2L1 inhibits centrosome disjunction in G2 and centrosome splitting induced by depletion of the centrosome linker rootletin. Conversely, GAS2L1 overexpression induces premature centrosome separation, and this activity requires GAS2L1 association with actin, microtubules, and the microtubule end-binding proteins. The centrosome-splitting effect of GAS2L1 is counterbalanced by rootletin, reflecting the opposing actions of GAS2L1 and the centrosome linker. Our work reveals a GAS2L1-mediated centriole-tethering mechanism of microtubules and actin, which provide the forces required for centrosome dynamics and separation.
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Affiliation(s)
- Franco K C Au
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yue Jia
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Kai Jiang
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Ilya Grigoriev
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Bill K T Hau
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yuehong Shen
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Shengwang Du
- Department of Physics and Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Anna Akhmanova
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Robert Z Qi
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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13
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Aurora A kinase modulates actin cytoskeleton through phosphorylation of Cofilin: Implication in the mitotic process. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2719-29. [PMID: 25090971 DOI: 10.1016/j.bbamcr.2014.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 11/22/2022]
Abstract
Aurora A kinase regulates early mitotic events through phosphorylation and activation of a variety of proteins. Specifically, Aur-A is involved in centrosomal separation and formation of mitotic spindles in early prophase. The effect of Aur-A on mitotic spindles is mediated by the modulation of microtubule dynamics and association with microtubule binding proteins. In this study we show that Aur-A exerts its effects on spindle organization through the regulation of the actin cytoskeleton. Aurora A phosphorylates Cofilin at multiple sites including S(3) resulting in the inactivation of its actin depolymerizing function. Aur-A interacts with Cofilin in early mitotic phases and regulates its phosphorylation status. Cofilin phosphorylation follows a dynamic pattern during the progression of prophase to metaphase. Inhibition of Aur-A activity induced a delay in the progression of prophase to metaphase. Aur-A inhibitor also disturbed the pattern of Cofilin phosphorylation, which correlated with the mitotic delay. Our results establish a novel function of Aur-A in the regulation of actin cytoskeleton reorganization, through Cofilin phosphorylation during early mitotic stages.
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Lancaster OM, Baum B. Shaping up to divide: coordinating actin and microtubule cytoskeletal remodelling during mitosis. Semin Cell Dev Biol 2014; 34:109-15. [PMID: 24607328 DOI: 10.1016/j.semcdb.2014.02.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 02/26/2014] [Indexed: 10/25/2022]
Abstract
Cell division requires the wholesale reorganization of cell architecture. At the same time as the microtubule network is remodelled to generate a bipolar spindle, animal cells entering mitosis replace their interphase actin cytoskeleton with a contractile mitotic actomyosin cortex that is tightly coupled to the plasma membrane--driving mitotic cell rounding. Here, we consider how these two processes are coordinated to couple chromosome segregation and cell division. In doing so we explore the relative roles of cell shape and the actin cortex in spindle morphogenesis, orientation and positioning.
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Affiliation(s)
- Oscar M Lancaster
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
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15
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Pihan GA. Centrosome dysfunction contributes to chromosome instability, chromoanagenesis, and genome reprograming in cancer. Front Oncol 2013; 3:277. [PMID: 24282781 PMCID: PMC3824400 DOI: 10.3389/fonc.2013.00277] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/28/2013] [Indexed: 12/19/2022] Open
Abstract
The unique ability of centrosomes to nucleate and organize microtubules makes them unrivaled conductors of important interphase processes, such as intracellular payload traffic, cell polarity, cell locomotion, and organization of the immunologic synapse. But it is in mitosis that centrosomes loom large, for they orchestrate, with clockmaker's precision, the assembly and functioning of the mitotic spindle, ensuring the equal partitioning of the replicated genome into daughter cells. Centrosome dysfunction is inextricably linked to aneuploidy and chromosome instability, both hallmarks of cancer cells. Several aspects of centrosome function in normal and cancer cells have been molecularly characterized during the last two decades, greatly enhancing our mechanistic understanding of this tiny organelle. Whether centrosome defects alone can cause cancer, remains unanswered. Until recently, the aggregate of the evidence had suggested that centrosome dysfunction, by deregulating the fidelity of chromosome segregation, promotes and accelerates the characteristic Darwinian evolution of the cancer genome enabled by increased mutational load and/or decreased DNA repair. Very recent experimental work has shown that missegregated chromosomes resulting from centrosome dysfunction may experience extensive DNA damage, suggesting additional dimensions to the role of centrosomes in cancer. Centrosome dysfunction is particularly prevalent in tumors in which the genome has undergone extensive structural rearrangements and chromosome domain reshuffling. Ongoing gene reshuffling reprograms the genome for continuous growth, survival, and evasion of the immune system. Manipulation of molecular networks controlling centrosome function may soon become a viable target for specific therapeutic intervention in cancer, particularly since normal cells, which lack centrosome alterations, may be spared the toxicity of such therapies.
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Affiliation(s)
- German A Pihan
- Department of Pathology and Laboratory Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, MA , USA
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16
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Charnley M, Anderegg F, Holtackers R, Textor M, Meraldi P. Effect of Cell Shape and Dimensionality on Spindle Orientation and Mitotic Timing. PLoS One 2013; 8:e66918. [PMID: 23825020 PMCID: PMC3688943 DOI: 10.1371/journal.pone.0066918] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 05/13/2013] [Indexed: 01/13/2023] Open
Abstract
The formation and orientation of the mitotic spindle is a critical feature of mitosis. The morphology of the cell and the spatial distribution and composition of the cells' adhesive microenvironment all contribute to dictate the position of the spindle. However, the impact of the dimensionality of the cells' microenvironment has rarely been studied. In this study we present the use of a microwell platform, where the internal surfaces of the individual wells are coated with fibronectin, enabling the three-dimensional presentation of adhesive ligands to single cells cultured within the microwells. This platform was used to assess the effect of dimensionality and cell shape in a controlled microenvironment. Single HeLa cells cultured in circular microwells exhibited greater tilting of the mitotic spindle, in comparison to cells cultured in square microwells. This correlated with an increase in the time required to align the chromosomes at the metaphase plate due to prolonged activation of the spindle checkpoint in an actin dependent process. The comparison to 2D square patterns revealed that the dimensionality of cell adhesions alone affected both mitotic timings and spindle orientation; in particular the role of actin varied according to the dimensionality of the cells' microenvironment. Together, our data revealed that cell shape and the dimensionality of the cells' adhesive environment impacted on both the orientation of the mitotic spindle and progression through mitosis.
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Affiliation(s)
- Mirren Charnley
- Laboratory for Surface Science and Technology, ETH Zurich, Zurich, Switzerland
- * E-mail:
| | - Fabian Anderegg
- Laboratory for Surface Science and Technology, ETH Zurich, Zurich, Switzerland
| | | | - Marcus Textor
- Laboratory for Surface Science and Technology, ETH Zurich, Zurich, Switzerland
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17
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Silkworth WT, Cimini D. Transient defects of mitotic spindle geometry and chromosome segregation errors. Cell Div 2012; 7:19. [PMID: 22883214 PMCID: PMC3509025 DOI: 10.1186/1747-1028-7-19] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 07/24/2012] [Indexed: 12/11/2022] Open
Abstract
Assembly of a bipolar mitotic spindle is essential to ensure accurate chromosome segregation and prevent aneuploidy, and severe mitotic spindle defects are typically associated with cell death. Recent studies have shown that mitotic spindles with initial geometric defects can undergo specific rearrangements so the cell can complete mitosis with a bipolar spindle and undergo bipolar chromosome segregation, thus preventing the risk of cell death associated with abnormal spindle structure. Although this may appear as an advantageous strategy, transient defects in spindle geometry may be even more threatening to a cell population or organism than permanent spindle defects. Indeed, transient spindle geometry defects cause high rates of chromosome mis-segregation and aneuploidy. In this review, we summarize our current knowledge on two specific types of transient spindle geometry defects (transient multipolarity and incomplete spindle pole separation) and describe how these mechanisms cause chromosome mis-segregation and aneuploidy. Finally, we discuss how these transient spindle defects may specifically contribute to the chromosomal instability observed in cancer cells.
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Affiliation(s)
- William T Silkworth
- Department of Biological Sciences, Virginia Tech, 1981 Kraft Dr, Blacksburg, VA, 24061, USA.
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18
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Abstract
The centrosome, which consists of two centrioles and the surrounding pericentriolar material, is the primary microtubule-organizing center (MTOC) in animal cells. Like chromosomes, centrosomes duplicate once per cell cycle and defects that lead to abnormalities in the number of centrosomes result in genomic instability, a hallmark of most cancer cells. Increasing evidence suggests that the separation of the two centrioles (disengagement) is required for centrosome duplication. After centriole disengagement, a proteinaceous linker is established that still connects the two centrioles. In G2, this linker is resolved (centrosome separation), thereby allowing the centrosomes to separate and form the poles of the bipolar spindle. Recent work has identified new players that regulate these two processes and revealed unexpected mechanisms controlling the centrosome cycle.
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Affiliation(s)
- Balca R Mardin
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, 69117 Heidelberg, Germany
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19
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Silkworth WT, Nardi IK, Paul R, Mogilner A, Cimini D. Timing of centrosome separation is important for accurate chromosome segregation. Mol Biol Cell 2011; 23:401-11. [PMID: 22130796 PMCID: PMC3268720 DOI: 10.1091/mbc.e11-02-0095] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Spindle assembly, establishment of kinetochore attachment, and sister chromatid separation must occur during mitosis in a highly coordinated fashion to ensure accurate chromosome segregation. In most vertebrate cells, the nuclear envelope must break down to allow interaction between microtubules of the mitotic spindle and the kinetochores. It was previously shown that nuclear envelope breakdown (NEB) is not coordinated with centrosome separation and that centrosome separation can be either complete at the time of NEB or can be completed after NEB. In this study, we investigated whether the timing of centrosome separation affects subsequent mitotic events such as establishment of kinetochore attachment or chromosome segregation. We used a combination of experimental and computational approaches to investigate kinetochore attachment and chromosome segregation in cells with complete versus incomplete spindle pole separation at NEB. We found that cells with incomplete spindle pole separation exhibit higher rates of kinetochore misattachments and chromosome missegregation than cells that complete centrosome separation before NEB. Moreover, our mathematical model showed that two spindle poles in close proximity do not "search" the entire cellular space, leading to formation of large numbers of syntelic attachments, which can be an intermediate stage in the formation of merotelic kinetochores.
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20
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Yi Q, Zhao X, Huang Y, Ma T, Zhang Y, Hou H, Cooke HJ, Yang DQ, Wu M, Shi Q. p53 dependent centrosome clustering prevents multipolar mitosis in tetraploid cells. PLoS One 2011; 6:e27304. [PMID: 22076149 PMCID: PMC3208627 DOI: 10.1371/journal.pone.0027304] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 10/13/2011] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND p53 abnormality and aneuploidy often coexist in human tumors, and tetraploidy is considered as an intermediate between normal diploidy and aneuploidy. The purpose of this study was to investigate whether and how p53 influences the transformation from tetraploidy to aneuploidy. PRINCIPAL FINDINGS Live cell imaging was performed to determine the fates and mitotic behaviors of several human and mouse tetraploid cells with different p53 status, and centrosome and spindle immunostaining was used to investigate centrosome behaviors. We found that p53 dominant-negative mutation, point mutation, or knockout led to a 2∼ 33-fold increase of multipolar mitosis in N/TERT1, 3T3 and mouse embryonic fibroblasts (MEFs), while mitotic entry and cell death were not significantly affected. In p53-/- tetraploid MEFs, the ability of centrosome clustering was compromised, while centrosome inactivation was not affected. Suppression of RhoA/ROCK activity by specific inhibitors in p53-/- tetraploid MEFs enhanced centrosome clustering, decreased multipolar mitosis from 38% to 20% and 16% for RhoA and ROCK, respectively, while expression of constitutively active RhoA in p53+/+ tetraploid 3T3 cells increased the frequency of multipolar mitosis from 15% to 35%. CONCLUSIONS p53 could not prevent tetraploid cells entering mitosis or induce tetraploid cell death. However, p53 abnormality impaired centrosome clustering and lead to multipolar mitosis in tetraploid cells by modulating the RhoA/ROCK signaling pathway.
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Affiliation(s)
- Qiyi Yi
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiaoyu Zhao
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Yun Huang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Tieliang Ma
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Yingyin Zhang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Heli Hou
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Howard J. Cooke
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
- MRC Human Genetics Unit and Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Da-Qing Yang
- Sanford Research/University of South Dakota, Sanford Health, Sioux Falls, South Dakota, United States of America
| | - Mian Wu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Qinghua Shi
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
- * E-mail:
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21
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Kaseda K, McAinsh AD, Cross RA. Dual pathway spindle assembly increases both the speed and the fidelity of mitosis. Biol Open 2011; 1:12-8. [PMID: 23213363 PMCID: PMC3507165 DOI: 10.1242/bio.2011012] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Roughly half of all animal somatic cell spindles assemble by the classical prophase pathway, in which the centrosomes separate ahead of nuclear envelope breakdown (NEBD). The remainder assemble by the prometaphase pathway, in which the centrosomes separate following NEBD. Why cells use dual pathway spindle assembly is unclear. Here, by examining the timing of NEBD relative to the onset of Eg5-mEGFP loading to centrosomes, we show that a time window of 9.2 ± 2.9 min is available for Eg5-driven prophase centrosome separation ahead of NEBD, and that those cells that succeed in separating their centrosomes within this window subsequently show >3-fold fewer chromosome segregation errors and a somewhat faster mitosis. A longer time window would allow more cells to complete prophase centrosome separation and further reduce segregation errors, but at the expense of a slower mitosis. Our data reveal dual pathway mitosis in a new light, as a substantive strategy that increases both the speed and the fidelity of mitosis.
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Affiliation(s)
- Kuniyoshi Kaseda
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick , Coventry CV4 7AL , UK
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22
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Magidson V, O’Connell CB, Lončarek J, Paul R, Mogilner A, Khodjakov A. The spatial arrangement of chromosomes during prometaphase facilitates spindle assembly. Cell 2011; 146:555-67. [PMID: 21854981 PMCID: PMC3291198 DOI: 10.1016/j.cell.2011.07.012] [Citation(s) in RCA: 226] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 04/17/2011] [Accepted: 07/08/2011] [Indexed: 11/19/2022]
Abstract
Error-free chromosome segregation requires stable attachment of sister kinetochores to the opposite spindle poles (amphitelic attachment). Exactly how amphitelic attachments are achieved during spindle assembly remains elusive. We employed photoactivatable GFP and high-resolution live-cell confocal microscopy to visualize complete 3D movements of individual kinetochores throughout mitosis in nontransformed human cells. Combined with electron microscopy, molecular perturbations, and immunofluorescence analyses, this approach reveals unexpected details of chromosome behavior. Our data demonstrate that unstable lateral interactions between kinetochores and microtubules dominate during early prometaphase. These transient interactions lead to the reproducible arrangement of chromosomes in an equatorial ring on the surface of the nascent spindle. A computational model predicts that this toroidal distribution of chromosomes exposes kinetochores to a high density of microtubules which facilitates subsequent formation of amphitelic attachments. Thus, spindle formation involves a previously overlooked stage of chromosome prepositioning which promotes formation of amphitelic attachments.
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Affiliation(s)
| | | | | | - Raja Paul
- Departments of Neurobiology, Physiology, and Behavior, and Mathematics, University of California, Davis, CA 95616, USA
| | - Alex Mogilner
- Departments of Neurobiology, Physiology, and Behavior, and Mathematics, University of California, Davis, CA 95616, USA
| | - Alexey Khodjakov
- Wadsworth Center, PO Box 509, Albany, NY 12201-509, USA
- Rensselaer Polytechnic Institute, Troy NY 12180, USA
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23
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Bolhy S, Bouhlel I, Dultz E, Nayak T, Zuccolo M, Gatti X, Vallee R, Ellenberg J, Doye V. A Nup133-dependent NPC-anchored network tethers centrosomes to the nuclear envelope in prophase. ACTA ACUST UNITED AC 2011; 192:855-71. [PMID: 21383080 PMCID: PMC3051818 DOI: 10.1083/jcb.201007118] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Centrosomes are closely associated with the nuclear envelope (NE) throughout the cell cycle and this association is maintained in prophase when they separate to establish the future mitotic spindle. At this stage, the kinetochore constituents CENP-F, NudE, NudEL, dynein, and dynactin accumulate at the NE. We demonstrate here that the N-terminal domain of the nuclear pore complex (NPC) protein Nup133, although largely dispensable for NPC assembly, is required for efficient anchoring of the dynein/dynactin complex to the NE in prophase. Nup133 exerts this function through an interaction network via CENP-F and NudE/EL. We show that this molecular chain is critical for maintaining centrosome association with the NE at mitotic entry and contributes to this process without interfering with the previously described RanBP2-BICD2-dependent pathway of centrosome anchoring. Finally, our study reveals that tethering of centrosomes to the nuclear surface at the G2/M transition contributes, along with other cellular mechanisms, to early stages of bipolar spindle assembly.
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Affiliation(s)
- Stéphanie Bolhy
- Cell Biology Program, Institut Jacques Monod, UMR 7592 Centre National de la Recherche Scientifique-Université Paris Diderot, 75205 Paris Cedex 13, France
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24
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Tanenbaum ME, Medema RH. Mechanisms of centrosome separation and bipolar spindle assembly. Dev Cell 2011; 19:797-806. [PMID: 21145497 DOI: 10.1016/j.devcel.2010.11.011] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 11/17/2010] [Accepted: 11/18/2010] [Indexed: 11/29/2022]
Abstract
Accurate segregation of chromosomes during cell division is accomplished through the assembly of a bipolar microtubule-based structure called the mitotic spindle. Work over the past two decades has identified a core regulator of spindle bipolarity, the microtubule motor protein kinesin-5. However, an increasing body of evidence has emerged demonstrating that kinesin-5-independent mechanisms driving bipolar spindle assembly exist as well. Here, we discuss different pathways that promote initial centrosome separation and bipolar spindle assembly.
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Affiliation(s)
- Marvin E Tanenbaum
- Department of Medical Oncology, University Medical Center, CG Utrecht, the Netherlands
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25
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Cao J, Crest J, Fasulo B, Sullivan W. Cortical actin dynamics facilitate early-stage centrosome separation. Curr Biol 2010; 20:770-6. [PMID: 20409712 DOI: 10.1016/j.cub.2010.02.060] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 02/19/2010] [Accepted: 02/19/2010] [Indexed: 02/07/2023]
Abstract
Proper centrosome separation is a prerequisite for positioning the bipolar spindle. Although studies demonstrate that microtubules (MTs) and their associated motors drive centrosome separation [1], the role of actin in centrosome separation remains less clear. Studies in tissue culture cells indicate that actin- and myosin-based cortical flow is primarily responsible for driving late centrosome separation [2], whereas other studies suggest that actin plays a more passive role by serving as an attachment site for astral MTs to pull centrosomes apart [3-6]. Here we demonstrate that prior to nuclear envelope breakdown (NEB) in Drosophila embryos, proper centrosome separation does not require myosin II but requires dynamic actin rearrangements at the growing edge of the interphase cap. Both Arp2/3- and Formin-mediated actin remodeling are required for separating the centrosome pairs before NEB. The Apc2-Armadillo complex appears to link cap expansion to centrosome separation. In contrast, the mechanisms driving centrosome separation after NEB are independent of the actin cytoskeleton and compensate for earlier separation defects. Our studies show that the dynamics of actin polymerization drive centrosome separation, and this has important implications for centrosome positioning during processes such as cell migration [7, 8], cell polarity maintenance [9, 10], and asymmetric cell division [11, 12].
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Affiliation(s)
- Jian Cao
- Sinsheimer Laboratories, Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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26
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Wang W, Chen L, Ding Y, Jin J, Liao K. Centrosome separation driven by actin-microfilaments during mitosis is mediated by centrosome-associated tyrosine-phosphorylated cortactin. J Cell Sci 2008; 121:1334-43. [PMID: 18388321 DOI: 10.1242/jcs.018176] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The regulation of protein tyrosine phosphorylation is an important aspect during the cell cycle. From G2-M transition to mitotic anaphase, phosphorylation of Tyr421, Tyr466 and Tyr482 of cortactin, an actin-filament associated protein, is dramatically induced. The phosphorylated cortactin is almost exclusively associated with centrosomes or spindle poles during mitosis. At G2-M transition prior to the breakdown of the nuclear envelope, two duplicated centrosomes migrate towards opposite ends of the nucleus to form the spindle poles. This centrosome-separation process and also the start of mitosis are inhibited or delayed by the depolymerization of actin filaments. Also inhibited is the separation of centrosomes when a truncated form of cortactin is expressed, whose C-terminus contains the tyrosine phosphorylation region but lacks the actin-binding domains. We introduced mutations at the tyrosine phosphorylation sites in the truncated C-terminus of cortactin and found that the C-terminus could no longer interfere with centrosome separation process. Our study shows that, cortactin phosphorylated at Tyr421, Tyr466 and Tyr482 mediates the actin-filament-driven centrosome separation at G2-M transition by providing a bridge between the centrosome and actin-filaments.
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Affiliation(s)
- Wenqi Wang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
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27
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Abstract
The gene encoding the Aurora-A protein kinase is located in the 20q13 breast cancer amplicon and is also overexpressed in colorectal, pancreatic and gastric tumours. Although Aurora-A may not be a bona fide oncoprotein in humans, it is a promising drug target in cancer therapy. Thus, it is surprising that so little is known of its role in normal cells. The primary function of Aurora-A is to promote bipolar spindle assembly, but the molecular details of this process remained obscure until recently. The discovery of several novel Aurora-A-binding proteins and substrates has implicated Aurora-A in centrosome maturation and separation, acentrosomal and centrosomal spindle assembly, kinetochore function, cytokinesis and in cell fate determination. Here we discuss recent advances in determining the early mitotic role of Aurora-A, with a strong emphasis on its function at the mitotic spindle poles.
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Affiliation(s)
- Alexis R Barr
- Cancer Research UK Cambridge Research Institute, Department of Oncology, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK
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28
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Patzke S, Stokke T, Aasheim HC. CSPP and CSPP-L associate with centrosomes and microtubules and differently affect microtubule organization. J Cell Physiol 2006; 209:199-210. [PMID: 16826565 DOI: 10.1002/jcp.20725] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We recently described the identification of a centrosome/spindle pole associated protein, CSPP, involved in cell cycle progression. Here we report a CSPP isoform denoted CSPP-L, with a 294 amino acids longer N-terminus and a 51 amino acids insertion located in the coiled-coil mid-domain. Expression analysis indicates an inverse cell cycle dependent regulation. CSPP mRNA expression is highest in G1 whereas CSPP-L expression is highest in G2/M. Ectopic expression of CSPP-L impairs cell cycle progression weaker in G1 than CSPP. Furthermore, normal mitotic phenotypes were observed in CSPP-L but not in CSPP transfectants. CSPP-L relocates from spindle microtubules and poles in metaphase to the mid-spindle in anaphase and concentrates at the mid-body in telophase/cytokinesis. CSPP-L high-expressing mitotic cells were predominantly characterized by lagging chromosomes or monopolar spindles, in contrast to the predominant multipolar spindles observed with CSPP expression. The different effects of CSPP and CSPP-L on microtubule organization in mitosis depend on the coiled-coil mid-domain insertion. The common C-terminal domain is required to repress that activity until mitosis. Notably, this C-terminal domain alone can associate with centrosomes in a microtubule independent manner. Taken together, CSPP and CSPP-L interact with centrosomes and microtubules and can differently affect microtubule organization.
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Affiliation(s)
- Sebastian Patzke
- Department of Immunology, The Norwegian Radium Hospital, Montebello, Oslo, Norway
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29
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Bahe S, Stierhof YD, Wilkinson CJ, Leiss F, Nigg EA. Rootletin forms centriole-associated filaments and functions in centrosome cohesion. J Cell Biol 2005; 171:27-33. [PMID: 16203858 PMCID: PMC2171225 DOI: 10.1083/jcb.200504107] [Citation(s) in RCA: 259] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 09/02/2005] [Indexed: 12/03/2022] Open
Abstract
After duplication of the centriole pair during S phase, the centrosome functions as a single microtubule-organizing center until the onset of mitosis, when the duplicated centrosomes separate for bipolar spindle formation. The mechanisms regulating centrosome cohesion and separation during the cell cycle are not well understood. In this study, we analyze the protein rootletin as a candidate centrosome linker component. As shown by immunoelectron microscopy, endogenous rootletin forms striking fibers emanating from the proximal ends of centrioles. Moreover, rootletin interacts with C-Nap1, a protein previously implicated in centrosome cohesion. Similar to C-Nap1, rootletin is phosphorylated by Nek2 kinase and is displaced from centrosomes at the onset of mitosis. Whereas the overexpression of rootletin results in the formation of extensive fibers, small interfering RNA-mediated depletion of either rootletin or C-Nap1 causes centrosome splitting, suggesting that both proteins contribute to maintaining centrosome cohesion. The ability of rootletin to form centriole-associated fibers suggests a dynamic model for centrosome cohesion based on entangling filaments rather than continuous polymeric linkers.
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Affiliation(s)
- Susanne Bahe
- Department of Cell Biology, Max-Planck-Institute for Biochemistry, D-82152 Martinsried, Germany
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Brito DA, Strauss J, Magidson V, Tikhonenko I, Khodjakov A, Koonce MP. Pushing forces drive the comet-like motility of microtubule arrays in Dictyostelium. Mol Biol Cell 2005; 16:3334-40. [PMID: 15857957 PMCID: PMC1165415 DOI: 10.1091/mbc.e05-01-0057] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Overexpression of dynein fragments in Dictyostelium induces the movement of the entire interphase microtubule array. Centrosomes in these cells circulate through the cytoplasm at rates between 0.4 and 2.5 microm/s and are trailed by a comet-tail like arrangement of the microtubule array. Previous work suggested that these cells use a dynein-mediated pulling mechanism to generate this dramatic movement and that similar forces are at work to maintain the interphase MTOC position in wild-type cells. In the present study, we address the nature of the forces used to produce microtubule movement. We have used a laser microbeam to sever the connection between the motile centrosomes and trailing microtubules, demonstrating that the major force for such motility results from a pushing on the microtubules. We eliminate the possibility that microtubule assembly/disassembly reactions are significant contributors to this motility and suggest that the cell cortex figures prominently in locating force-producing molecules. Our findings indicate that interphase microtubules in Dictyostelium are subject to both dynein- and kinesin-like forces and that these act in concert to maintain centrosome position in the cell and to support the radial character of the microtubule network.
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Affiliation(s)
- Daniela A Brito
- Division of Molecular Medicine, Wadsworth Center, Albany, NY 12201, USA
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Rosenblatt J, Cramer LP, Baum B, McGee KM. Myosin II-dependent cortical movement is required for centrosome separation and positioning during mitotic spindle assembly. Cell 2004; 117:361-72. [PMID: 15109496 DOI: 10.1016/s0092-8674(04)00341-1] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Revised: 02/25/2004] [Accepted: 02/25/2004] [Indexed: 10/26/2022]
Abstract
The role of myosin II in mitosis is generally thought to be restricted to cytokinesis. We present surprising new evidence that cortical myosin II is also required for spindle assembly in cells. Drug- or RNAi-mediated disruption of myosin II in cells interferes with normal spindle assembly and positioning. Time-lapse movies reveal that these treatments block the separation and positioning of duplicated centrosomes after nuclear envelope breakdown (NEBD), thereby preventing the migration of the microtubule asters to opposite sides of chromosomes. Immobilization of cortical movement with tetravalent lectins produces similar spindle defects to myosin II disruption and suggests that myosin II activity is required within the cortex. Latex beads bound to the cell surface move in a myosin II-dependent manner in the direction of the separating asters. We propose that after NEBD, completion of centrosome separation and positioning around chromosomes depends on astral microtubule connections to a moving cell cortex.
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Affiliation(s)
- Jody Rosenblatt
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London SC1E 6BT, United Kingdom.
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Ou Y, Rattner JB. The Centrosome in Higher Organisms: Structure, Composition, and Duplication. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 238:119-82. [PMID: 15364198 DOI: 10.1016/s0074-7696(04)38003-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The centrosome found in higher organisms is an organelle with a complex and dynamic architecture and composition. This organelle not only functions as a microtubule-organizing center, but also is integrated with or impacts a number of cellular processes. Defects associated with this organelle have been linked to a variety of human diseases including several forms of cancer. Here we review the emerging picture of how the structure, composition, duplication, and function of the centrosome found in higher organisms are interrelated.
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Affiliation(s)
- Young Ou
- Department of Cell Biology and Anatomy, University of Calgary 3330 Hospital Drive NW, Calgary, Alberta, Canada
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Gerisch G, Faix J, Köhler J, Müller-Taubenberger A. Actin-binding proteins required for reliable chromosome segregation in mitosis. ACTA ACUST UNITED AC 2004; 57:18-25. [PMID: 14648554 DOI: 10.1002/cm.10150] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
While studying mitosis in Dictyostelium mutants with deficiencies in actin-binding proteins, we found that two of these proteins, cortexillin and Aip1, are required for the precise segregation of chromosomes. Atypical spindles and nuclei with varying DNA content indicate that mutants lacking cortexillin or Aip1 are genetically unstable. These aberrations are caused by the detachment and irregular reattachment of centrosomes to the nuclear surface. Live imaging showed how coalescing mitotic complexes give rise to a multipolar spindle, and how excess centrosomes can be eliminated by mitotic cleavage between anucleate and nucleated portions of a cell. We hypothesize that mutations in regulatory proteins of the actin network might be one cause of genetic instability of malignant tumor cells.
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Abstract
Mammalian aurora-A belongs to a multigenic family of mitotic serine/threonine kinases comprising two other members: aurora-B and aurora-C. In this review we will focus on aurora-A that starts to localize to centrosomes only in S phase as soon as centrioles have been duplicated, the protein is then degraded in early G1. Works in various organisms have revealed that the kinase is involved in centrosome separation, duplication and maturation as well as in bipolar spindle assembly and stability. Aurora kinases are found in all organisms in which their function has been conserved throughout evolution, namely the control of chromosome segregation. In human, aurora-A has focused a lot of attention, since its overexpression has been found to be correlated with the grade of various solid tumours. Ectopic kinase overexpression in any culture cell line leads to polyploidy and centrosome amplification. However, overexpression of aurora-A in particular cell lines such as NIH3T3 is sufficient to induce growth on soft agar. Those transformed cells form tumours when implanted in immunodeficient mice, indicating that the kinase is an oncogene.
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Affiliation(s)
- Stéphanie Dutertre
- Groupe Cycle Cellulaire, UMR 6061 Génétique et développement, CNRS-Université de Rennes I, IFR 97 Génomique Fonctionnelle et Santé, Faculté de Médecine, 2 avenue du Pr Leon Bernard, CS 34317, 35043 Rennes cedex, France
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D'Assoro AB, Barrett SL, Folk C, Negron VC, Boeneman K, Busby R, Whitehead C, Stivala F, Lingle WL, Salisbury JL. Amplified centrosomes in breast cancer: a potential indicator of tumor aggressiveness. Breast Cancer Res Treat 2002; 75:25-34. [PMID: 12500932 DOI: 10.1023/a:1016550619925] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Molecular mechanisms leading to genomic instability and phenotypic variation during tumor development and progression are poorly understood. Such instability represents a major problem in the management of breast cancer because of its contribution to more aggressive phenotypes as well as chemoresistance. In this study we analyzed breast carcinomas and tumor-derived cell lines to determine the relationship between centrosome amplification and established prognostic factors. Our results show that centrosome amplification can arise independent of ER or p53 status and is a common feature of aneuploid breast tumors. Centrosome amplification is associated with mitotic spindle abnormalities in breast carcinomas and thus may contribute to genomic instability and the development of more aggressive phenotypes during tumor progression.
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36
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Faruki S, Cole RW, Rieder CL. Separating centrosomes interact in the absence of associated chromosomes during mitosis in cultured vertebrate cells. CELL MOTILITY AND THE CYTOSKELETON 2002; 52:107-21. [PMID: 12112153 DOI: 10.1002/cm.10036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We detail here how "free" centrosomes, lacking associated chromosomes, behave during mitosis in PtK(2) homokaryons stably expressing GFP-alpha-tubulin. As free centrosomes separate during prometaphase, their associated astral microtubules (Mts) interact to form a spindle-shaped array that is enriched for cytoplasmic dynein and Eg5. Over the next 30 min, these arrays become progressively depleted of Mts until the two centrosomes are linked by a single bundle, containing 10-20 Mts, that persists for > 60 min. The overlapping astral Mts within this bundle are loosely organized, and their plus ends terminate near its midzone, which is enriched for an ill-defined matrix material. At this time, the distance between the centrosomes is not defined by external forces because these organelles remain stationary when the bundle connecting them is severed by laser microsurgery. However, since the centrosomes move towards one another in response to monastrol treatment, the kinesin-like motor protein Eg5 is involved. From these results, we conclude that separating asters interact during prometaphase of mitosis to form a spindle-shaped Mt array, but that in the absence of chromosomes this array is unstable. An analysis of the existing data suggests that the stabilization of spindle Mts during mitosis in vertebrates does not involve the chromatin (i.e., the RCC1/RanGTP pathway), but instead some other chromosomal component, e.g., kinetochores.
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Affiliation(s)
- Shamsa Faruki
- Division of Molecular Medicine, Wadsworth Center for Laboratories and Research, Empire State Plaza, Albany, New York, USA
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Ou YY, Rattner JB. Post-karyokinesis centrosome movement leaves a trail of unanswered questions. CELL MOTILITY AND THE CYTOSKELETON 2002; 51:123-32. [PMID: 11921169 DOI: 10.1002/cm.10019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The centrosome is a complex structure composed of a large number of proteins (pericentriolar material, PCM) usually organized around a pair of centrioles (or a centriole duplex). This structure is capable of nucleating and organizing microtubules, duplication, and motility. In general, episodes of dramatic centrosome movement correlate with periods of cellular reorganization and nowhere is cellular reorganization more apparent, or more important, than in the periods before and after cell division. It is now clear that centrosome movement occurs not only prior to cell division but also at its completion, in concert with cytokinesis. The focus of this review is the newly emerging picture of centrosome activity during the post-karyokinesis period and the role that this activity might play in the transition of cells from mitosis to interphase.
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Affiliation(s)
- Young Y Ou
- Department of Anatomy and Cell Biology, The University of Calgary, Calgary, Alberta, Canada
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38
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Abstract
The centrosome found in animal cells is a complex and dynamic organelle that functions as the major microtubule organizing center. Structural studies over the past several decades have defined the primary structural features of the centrosome but recent studies are now beginning to reveal structural detail previously unknown. Concurrent with these studies has been an explosion in the identification of the proteins that reside within the centrosome. Our growing understanding of how protein composition integrates with centrosome structure and hence with function is the focus of this review.
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Affiliation(s)
- G J Mack
- Department of Anatomy, Faculty of Medicine, University of Calgary, Canada
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39
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Abstract
Development and growth of all organisms involves the faithful reproduction of cells and requires that the genome be accurately replicated and equally partitioned between two cellular progeny. In human cells, faithful segregation of the genome is accomplished by an elaborate macromolecular machine, the mitotic spindle. It is not difficult to envision how defects in components of this complex machine molecules that control its organization and function and regulators that temporally couple spindle operation to other cell cycle events could lead to chromosome missegregation. Recent evidence indicates that the persistent missegregation of chromosomes result in gains and losses of chromosomes and may be an important cause of aneuploidy. This form of chromosome instability may contribute to tumor development and progression by facilitating loss of heterozygocity (LOH) and the phenotypic expression of mutated tumor suppressor genes, and by favoring polysomy of chromosomes that harbor oncogenes. In this review, we will discuss mitotic defects that cause chromosome missegregation, examine components and regulatory mechanisms of the mitotic machine implicated in cancer, and explore mechanisms by which chromosome missegregation could lead to cancer.
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Affiliation(s)
- G A Pihan
- Department of Pathology and Program in Molecu-$blar Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA, 01605, USA
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40
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Whitehead CM, Rattner JB. Expanding the role of HsEg5 within the mitotic and post-mitotic phases of the cell cycle. J Cell Sci 1998; 111 ( Pt 17):2551-61. [PMID: 9701554 DOI: 10.1242/jcs.111.17.2551] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The BimC family of kinesin like proteins are involved in spindle dynamics in a wide variety of organisms. The human member of this family, HsEg5, has been implicated in centrosome separation during prophase/prometaphase and in the organization of in vitro mitotic asters. HsEg5 displays a complex distribution during mitosis, associating with the centrosomes, spindle microtubules, specific regions of the intracellular bridge and a microtubule bundle that forms in association with the post-mitotic migration of the centrosome. In an effort to determine the function of HsEg5 during late mitotic events and refine its proposed function during early mitotic centrosome separation, we microinjected antibodies specific to HsEg5 into HeLa cells during various stages of mitosis. In the presence of HsEg5 antibodies we find that the microtubule arrays responsible for both pre- and post-mitotic centrosome movement never form. Similarly, the microtubule bundle within the intracellular bridge becomes prematurely altered following karyokinesis resulting in the loss of the microtubule array at either end of the bridge. In addition, some peri-centrosomal material at the spindle poles becomes fragmented and the distribution of the spindle protein NuMA becomes more concentrated at the minus ends of the spindle microtubules. Our study also provides direct evidence that there is a link between post-mitotic centrosome migration and Golgi complex positioning and reformation following mitosis. We conclude that HsEg5 plays a recurrent role in establishing and/or determining the stability of specific microtubule arrays that form during cell division and that this role may encompass the ability of HsEg5 to influence the distribution of other protein components associated with cell division
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Affiliation(s)
- C M Whitehead
- Department of Medical Biochemistry, University of Calgary, Calgary, Alberta, Canada
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Kashina AS, Rogers GC, Scholey JM. The bimC family of kinesins: essential bipolar mitotic motors driving centrosome separation. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1357:257-71. [PMID: 9268050 DOI: 10.1016/s0167-4889(97)00037-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- A S Kashina
- Section of Molecular and Cellular Biology, University of California, Davis 95616, USA
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