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Klaasen SJ, Kops GJPL. Chromosome Inequality: Causes and Consequences of Non-Random Segregation Errors in Mitosis and Meiosis. Cells 2022; 11:3564. [PMID: 36428993 PMCID: PMC9688425 DOI: 10.3390/cells11223564] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/01/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Aneuploidy is a hallmark of cancer and a major cause of miscarriages in humans. It is caused by chromosome segregation errors during cell divisions. Evidence is mounting that the probability of specific chromosomes undergoing a segregation error is non-random. In other words, some chromosomes have a higher chance of contributing to aneuploid karyotypes than others. This could have important implications for the origins of recurrent aneuploidy patterns in cancer and developing embryos. Here, we review recent progress in understanding the prevalence and causes of non-random chromosome segregation errors in mammalian mitosis and meiosis. We evaluate its potential impact on cancer and human reproduction and discuss possible research avenues.
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Affiliation(s)
- Sjoerd J. Klaasen
- Hubrecht Institute—KNAW (Royal Netherlands Academy of Arts and Sciences) and University Medical Centre Utrecht, 3584 CT Utrecht, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Geert J. P. L. Kops
- Hubrecht Institute—KNAW (Royal Netherlands Academy of Arts and Sciences) and University Medical Centre Utrecht, 3584 CT Utrecht, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
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2
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Julner A, Abbasi M, Menéndez-Benito V. The microtubule plus-end tracking protein Bik1 is required for chromosome congression. Mol Biol Cell 2022; 33:br7. [PMID: 35235370 PMCID: PMC9282014 DOI: 10.1091/mbc.e21-10-0500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
During mitosis, sister chromatids congress on both sides of the spindle equator to facilitate the correct partitioning of the genomic material. Chromosome congression requires a finely tuned control of microtubule dynamics by the kinesin motor proteins. In Saccharomyces cerevisiae, the kinesin proteins Cin8, Kip1, and Kip3 have a pivotal role in chromosome congression. It has been hypothesized that additional proteins that modulate microtubule dynamics are involved. Here, we show that the microtubule plus-end tracking protein Bik1—the budding yeast ortholog of CLIP-170—is essential for chromosome congression. We find that nuclear Bik1 localizes to the kinetochores in a cell cycle–dependent manner. Disrupting the nuclear pool of Bik1 with a nuclear export signal (Bik1-NES) leads to slower cell-cycle progression characterized by a delayed metaphase–anaphase transition. Bik1-NES cells have mispositioned kinetochores along the spindle in metaphase. Furthermore, using proximity-dependent methods, we identify Cin8 as an interaction partner of Bik1. Deleting CIN8 reduces the amount of Bik1 at the spindle. In contrast, Cin8 retains its typical bilobed distribution in the Bik1-NES mutant and does not localize to the unclustered kinetochores. We propose that Bik1 functions with Cin8 to regulate kinetochore–microtubule dynamics for correct kinetochore positioning and chromosome congression.
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Affiliation(s)
- Alexander Julner
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83, Huddinge, Sweden
| | - Marjan Abbasi
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83, Huddinge, Sweden
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3
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Campos Medina MA, Iemura K, Kimura A, Tanaka K. A mathematical model of kinetochore-microtubule attachment regulated by Aurora A activity gradient describes chromosome oscillation and correction of erroneous attachments. Biomed Res 2021; 42:203-219. [PMID: 34544996 DOI: 10.2220/biomedres.42.203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Chromosome oscillation during metaphase is attenuated in cancer cell lines, concomitant with the reduction of Aurora A activity on kinetochores, which results in reduced mitotic fidelity. To verify the correlation between Aurora A activity, chromosome oscillation, and error correction efficiency, we developed a mathematical model of kinetochore-microtubule dynamics, based on stochastic attachment/detachment events regulated by Aurora A activity gradient centered at spindle poles. The model accurately reproduced the oscillatory movements of chromosomes, which were suppressed not only when Aurora A activity was inhibited, but also when it was upregulated, mimicking the situation in cancer cells. Our simulation also predicted efficient correction of erroneous attachments through chromosome oscillation, which was hampered by both inhibition and upregulation of Aurora A activity. Our model provides a framework to understand the physiological role of chromosome oscillation in the correction of erroneous attachments that is intrinsically related to Aurora A activity.
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Affiliation(s)
- Manuel Alejandro Campos Medina
- Department of Molecular Oncology, Institute of Development, Aging and Cancer, Tohoku University.,Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology
| | - Kenji Iemura
- Department of Molecular Oncology, Institute of Development, Aging and Cancer, Tohoku University
| | - Akatsuki Kimura
- Cell Architecture Laboratory, Department of Chromosome Science, National Institute of Genetics; Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI)
| | - Kozo Tanaka
- Department of Molecular Oncology, Institute of Development, Aging and Cancer, Tohoku University
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Iemura K, Yoshizaki Y, Kuniyasu K, Tanaka K. Attenuated Chromosome Oscillation as a Cause of Chromosomal Instability in Cancer Cells. Cancers (Basel) 2021; 13:cancers13184531. [PMID: 34572757 PMCID: PMC8470601 DOI: 10.3390/cancers13184531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Chromosomal instability (CIN), a condition in which chromosome missegregation occurs at high rates, is widely seen in cancer cells. Causes of CIN in cancer cells are not fully understood. A recent report suggests that chromosome oscillation, an iterative chromosome motion typically seen in metaphase around the spindle equator, is attenuated in cancer cells, and is associated with CIN. Chromosome oscillation promotes the correction of erroneous kinetochore-microtubule attachments through phosphorylation of Hec1, a kinetochore protein that binds to microtubules, by Aurora A kinase residing on the spindle. In this review, we focused on this unappreciated link between chromosome oscillation and CIN. Abstract Chromosomal instability (CIN) is commonly seen in cancer cells, and related to tumor progression and poor prognosis. Among the causes of CIN, insufficient correction of erroneous kinetochore (KT)-microtubule (MT) attachments plays pivotal roles in various situations. In this review, we focused on the previously unappreciated role of chromosome oscillation in the correction of erroneous KT-MT attachments, and its relevance to the etiology of CIN. First, we provided an overview of the error correction mechanisms for KT-MT attachments, especially the role of Aurora kinases in error correction by phosphorylating Hec1, which connects MT to KT. Next, we explained chromosome oscillation and its underlying mechanisms. Then we introduced how chromosome oscillation is involved in the error correction of KT-MT attachments, based on recent findings. Chromosome oscillation has been shown to promote Hec1 phosphorylation by Aurora A which localizes to the spindle. Finally, we discussed the link between attenuated chromosome oscillation and CIN in cancer cells. This link underscores the role of chromosome dynamics in mitotic fidelity, and the mutual relationship between defective chromosome dynamics and CIN in cancer cells that can be a target for cancer therapy.
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Park JH, Park M, Park SY, Lee YJ, Hong SC, Jung EJ, Ju YT, Jeong CY, Kim JY, Ko GH, Hah YS, Jeong SH. ERH overexpression is associated with decreased cell migration and invasion and a good prognosis in gastric cancer. Transl Cancer Res 2020; 9:5281-5291. [PMID: 35117894 PMCID: PMC8797358 DOI: 10.21037/tcr-20-1498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/08/2020] [Indexed: 12/23/2022]
Abstract
Background The enhancer of rudimentary homolog (ERH) protein is implicated in transcriptional regulation, cell cycle progression, and malignancy. We previously conducted a proteomics analysis using gastric cancer (GC) tissues and identified ERH as a biomarker candidate. The aim of this study was to investigate whether ERH may be useful as a prognostic marker for GC. Methods Surgically resected GC tissue specimens were obtained from 327 patients who underwent gastrectomy at Gyeongsang National University Hospital. Immunohistochemistry (IHC) was used to validate ERH as a prognostic marker in these tissues. SNU601 and MKN74 cells with siRNA-mediated knockdown of ERH expression and ERH-overexpressing SNU601 and MKN74 knock-in cells were used for analysis of ERH function. Results ERH was overexpressed in stomach cancer tissues compared with normal tissues according to proteomics analysis (n=29, P<0.01) of patient samples. Based on IHC, patients with tumors overexpressing ERH had lower T stage and lower TNM stage classifications, lower cancer recurrence rates and longer survival times than did patients with tumors showing low expression of ERH (P=0.04). In vitro, forced expression of ERH significantly decreased GC cell migration and invasion, and depletion of ERH triggered GC cell migration and invasion but had no effect on proliferation in vitro. Conclusions The findings from the present study show that ERH is associated with decreased cancer cell migration and invasion, suggesting that overexpression of ERH may serve as a marker of good prognosis for patients with GC.
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Affiliation(s)
- Ji-Ho Park
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Miyeong Park
- Department of Anesthesiology, Gyeongsang National University Changwon Hospital, Changwon, Korea
| | - Sun Yi Park
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Young-Joon Lee
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Soon-Chan Hong
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Eun-Jung Jung
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Young-Tae Ju
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Chi-Young Jeong
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Ju-Yeon Kim
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
| | - Gyung Hyuck Ko
- Department of Pathology, School of Medicine, Gyeongsang National University, Jinju, Korea
| | - Young-Sool Hah
- Biomedical Research Institute, Gyeongsang National University Hospital, Jinju, Korea
| | - Sang-Ho Jeong
- Department of Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Korea
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6
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Chu L, Liang Z, Mukhina M, Fisher J, Vincenten N, Zhang Z, Hutchinson J, Zickler D, Kleckner N. The 3D Topography of Mitotic Chromosomes. Mol Cell 2020; 79:902-916.e6. [PMID: 32768407 DOI: 10.1016/j.molcel.2020.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/16/2020] [Accepted: 07/06/2020] [Indexed: 01/08/2023]
Abstract
A long-standing conundrum is how mitotic chromosomes can compact, as required for clean separation to daughter cells, while maintaining close parallel alignment of sister chromatids. Pursuit of this question, by high resolution 3D fluorescence imaging of living and fixed mammalian cells, has led to three discoveries. First, we show that the structural axes of separated sister chromatids are linked by evenly spaced "mini-axis" bridges. Second, when chromosomes first emerge as discrete units, at prophase, they are organized as co-oriented sister linear loop arrays emanating from a conjoined axis. We show that this same basic organization persists throughout mitosis, without helical coiling. Third, from prophase onward, chromosomes are deformed into sequential arrays of half-helical segments of alternating handedness (perversions), accompanied by correlated kinks. These arrays fluctuate dynamically over <15 s timescales. Together these discoveries redefine the foundation for thinking about the evolution of mitotic chromosomes as they prepare for anaphase segregation.
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Affiliation(s)
- Lingluo Chu
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Zhangyi Liang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Maria Mukhina
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Jay Fisher
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA; Redbud Labs, Research Triangle, NC 27709, USA
| | - Nadine Vincenten
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Zheng Zhang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA; CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China
| | - John Hutchinson
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Denise Zickler
- University Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif sur Yvette, France
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
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7
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Kops GJPL, Gassmann R. Crowning the Kinetochore: The Fibrous Corona in Chromosome Segregation. Trends Cell Biol 2020; 30:653-667. [PMID: 32386879 DOI: 10.1016/j.tcb.2020.04.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 01/30/2023]
Abstract
The kinetochore is at the heart of chromosome segregation in mitosis and meiosis. Rather than a static linker complex for chromatin and spindle microtubules, it is highly dynamic in composition, size, and shape. While known for decades that it can expand and grow a fibrous meshwork known as the corona, it was until recently unclear what constitutes this 'crown' and what its relevance is for kinetochore function. Here, we highlight recent discoveries in fibrous corona biology, and place them in the context of the processes that orchestrate high-fidelity chromosome segregation.
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Affiliation(s)
- Geert J P L Kops
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Centre Utrecht, Utrecht, 3584, CT, The Netherlands.
| | - Reto Gassmann
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.
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8
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Warren JD, Orr B, Compton DA. A comparative analysis of methods to measure kinetochore-microtubule attachment stability. Methods Cell Biol 2020; 158:91-116. [PMID: 32423652 PMCID: PMC7727308 DOI: 10.1016/bs.mcb.2020.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
During mitosis, spindle microtubules dynamically attach to and detach from kinetochores in a precise and regulated fashion. To ensure mitotic fidelity, kinetochore-microtubule (k-MT) attachments must be stable enough to satisfy the spindle assembly checkpoint (SAC), but sufficiently unstable to facilitate the correction of maloriented attachments. Different methods are available to assess k-MT stability in both live and fixed cells, but a comparative survey of these methods has not yet been reported. Here, we evaluate several quantitative and semiquantitative methods for determining k-MT stability and apply each technique to illustrate changes in spindle microtubule dynamics upon perturbation with physiologically relevant concentrations of microtubule stabilizing (Taxol) and destabilizing (UMK57 and nocodazole) compounds. We discuss the utility of each technique for defining specific features of spindle microtubule dynamics and k-MT attachment stability.
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Affiliation(s)
- Jessica D Warren
- Department of Biochemistry and Cell Biology, Geisel School of Medicine, Hanover, NH, United States; Norris Cotton Cancer Center, Lebanon, NH, United States
| | - Bernardo Orr
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Duane A Compton
- Department of Biochemistry and Cell Biology, Geisel School of Medicine, Hanover, NH, United States; Norris Cotton Cancer Center, Lebanon, NH, United States.
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Vukušić K, Buđa R, Tolić IM. Force-generating mechanisms of anaphase in human cells. J Cell Sci 2019; 132:132/18/jcs231985. [DOI: 10.1242/jcs.231985] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
ABSTRACT
What forces drive chromosome segregation remains one of the most challenging questions in cell division. Even though the duration of anaphase is short, it is of utmost importance for genome fidelity that no mistakes are made. Seminal studies in model organisms have revealed different mechanisms operating during chromosome segregation in anaphase, but the translation of these mechanisms to human cells is not straightforward. Recent work has shown that kinetochore fiber depolymerization during anaphase A is largely motor independent, whereas spindle elongation during anaphase B is coupled to sliding of interpolar microtubules in human cells. In this Review, we discuss the current knowledge on the mechanisms of force generation by kinetochore, interpolar and astral microtubules. By combining results from numerous studies, we propose a comprehensive picture of the role of individual force-producing and -regulating proteins. Finally, by linking key concepts of anaphase to most recent data, we summarize the contribution of all proposed mechanisms to chromosome segregation and argue that sliding of interpolar microtubules and depolymerization at the kinetochore are the main drivers of chromosome segregation during early anaphase in human cells.
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Affiliation(s)
- Kruno Vukušić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Renata Buđa
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Iva M. Tolić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
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Fonseca CL, Malaby HLH, Sepaniac LA, Martin W, Byers C, Czechanski A, Messinger D, Tang M, Ohi R, Reinholdt LG, Stumpff J. Mitotic chromosome alignment ensures mitotic fidelity by promoting interchromosomal compaction during anaphase. J Cell Biol 2019; 218:1148-1163. [PMID: 30733233 PMCID: PMC6446859 DOI: 10.1083/jcb.201807228] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/21/2018] [Accepted: 01/09/2019] [Indexed: 01/27/2023] Open
Abstract
Chromosome alignment at the equator of the mitotic spindle is a highly conserved step during cell division; however, its importance to genomic stability and cellular fitness is not understood. Normal mammalian somatic cells lacking KIF18A function complete cell division without aligning chromosomes. These alignment-deficient cells display normal chromosome copy numbers in vitro and in vivo, suggesting that chromosome alignment is largely dispensable for maintenance of euploidy. However, we find that loss of chromosome alignment leads to interchromosomal compaction defects during anaphase, abnormal organization of chromosomes into a single nucleus at mitotic exit, and the formation of micronuclei in vitro and in vivo. These defects slow cell proliferation and are associated with impaired postnatal growth and survival in mice. Our studies support a model in which the alignment of mitotic chromosomes promotes proper organization of chromosomes into a single nucleus and continued proliferation by ensuring that chromosomes segregate as a compact mass during anaphase.
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Affiliation(s)
- Cindy L Fonseca
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | - Heidi L H Malaby
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | - Leslie A Sepaniac
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | | | | | | | - Dana Messinger
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | - Mary Tang
- Department of Pathology, University of Vermont, Burlington, VT
| | - Ryoma Ohi
- Department of Cell and Developmental Biology, Vanderbilt University Medical School, Nashville, TN
- The Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | | | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
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Olziersky AM, Smith CA, Burroughs N, McAinsh AD, Meraldi P. Mitotic live-cell imaging at different timescales. Methods Cell Biol 2018; 145:1-27. [PMID: 29957199 DOI: 10.1016/bs.mcb.2018.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mitosis is a highly dynamic and choreographed process in which chromosomes are captured by the mitotic spindle and physically segregated into the two daughter cells to ensure faithful transmission of the genetic material. Live-cell fluorescence microscopy enables these dynamics to be analyzed over diverse temporal scales. Here we present the methodologies to study chromosome segregation at three timescales: we first show how automated tracking of kinetochores enables investigation of mitotic spindle and chromosome dynamics in the seconds-to-minutes timescale; next we highlight how new DNA live dyes allow the study of chromosome segregation over a period of several hours in any cell line; finally, we demonstrate how image sequences acquired over several days can reveal the fate of whole cell populations over several consecutive cell divisions.
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Affiliation(s)
- Anna-Maria Olziersky
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Chris A Smith
- Centre for Mechanochemical Cell Biology & Division of Biomedical Science, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Nigel Burroughs
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
| | - Andrew D McAinsh
- Centre for Mechanochemical Cell Biology & Division of Biomedical Science, Warwick Medical School, University of Warwick, Coventry, United Kingdom.
| | - Patrick Meraldi
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
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12
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Sld5 Ensures Centrosomal Resistance to Congression Forces by Preserving Centriolar Satellites. Mol Cell Biol 2017; 38:MCB.00371-17. [PMID: 29061732 DOI: 10.1128/mcb.00371-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 10/11/2017] [Indexed: 11/20/2022] Open
Abstract
The migration of chromosomes during mitosis is mediated primarily by kinesins that bind to the chromosomes and move along the microtubules, exerting pulling and pushing forces on the centrosomes. We report that a DNA replication protein, Sld5, localizes to the centrosomes, resisting the microtubular pulling forces experienced during chromosome congression. In the absence of Sld5, centriolar satellites, which normally cluster around the centrosomes, are dissipated throughout the cytoplasm, resulting in the loss of their known function of recruiting the centrosomal protein, pericentrin. We observed that Sld5-deficient centrosomes lacking pericentrin were unable to endure the CENP-E- and Kid-mediated microtubular forces that converge on the centrosomes during chromosome congression, resulting in monocentriolar and acentriolar spindle poles. The minus-end-directed kinesin-14 motor protein, HSET, sustains the traction forces that mediate centrosomal fragmentation in Sld5-depleted cells. Thus, we report that a DNA replication protein has an as yet unknown function of ensuring spindle pole resistance to traction forces exerted during chromosome congression.
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13
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Kinetochore Function from the Bottom Up. Trends Cell Biol 2017; 28:22-33. [PMID: 28985987 DOI: 10.1016/j.tcb.2017.09.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 02/06/2023]
Abstract
During a single human lifetime, nearly one quintillion chromosomes separate from their sisters and transit to their destinations in daughter cells. Unlike DNA replication, chromosome segregation has no template, and, unlike transcription, errors frequently lead to a total loss of cell viability. Rapid progress in recent years has shown how kinetochores enable faithful execution of this process by connecting chromosomal DNA to microtubules. These findings have transformed our idea of kinetochores from cytological features to immense molecular machines and now allow molecular interpretation of many long-appreciated kinetochore functions. In this review we trace kinetochore protein connectivity from chromosomal DNA to microtubules, relating new findings to important points of regulation and function.
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14
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de Wolf B, Kops GJPL. Kinetochore Malfunction in Human Pathologies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1002:69-91. [DOI: 10.1007/978-3-319-57127-0_4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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15
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Barisic M, Maiato H. Dynein prevents erroneous kinetochore-microtubule attachments in mitosis. Cell Cycle 2016; 14:3356-61. [PMID: 26397382 DOI: 10.1080/15384101.2015.1089369] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Equal distribution of the genetic material during cell division relies on efficient congression of chromosomes to the metaphase plate. Prior to their alignment, the Dynein motor recruited to kinetochores transports a fraction of laterally-attached chromosomes along microtubules toward the spindle poles. By doing that, Dynein not only contributes to chromosome movements, but also prevents premature stabilization of end-on kinetochore-microtubule attachments. This is achieved by 2 parallel mechanisms: 1) Dynein-mediated poleward movement of chromosomes counteracts opposite polar-ejection forces (PEFs) on chromosome arms by the microtubule plus-end-directed motors chromokinesins. Otherwise, they could stabilize erroneous syntelic kinetochore-microtubule attachments and lead to the random ejection of chromosomes away from the spindle poles; and 2) By transporting chromosomes to the spindle poles, Dynein brings the former to the zone of highest Aurora A kinase activity, further destabilizing kinetochore-microtubule attachments. Thus, Dynein plays an important role in keeping chromosome segregation error-free by preventing premature stabilization of kinetochore-microtubule attachments near the spindle poles.
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Affiliation(s)
- Marin Barisic
- a Chromosome Instability & Dynamics Laboratory; Instituto de Biologia Molecular e Celular; Universidade do Porto ; Porto , Portugal.,b Instituto de Investigação e Inovação em Saúde - i3S; Universidade do Porto ; Portugal
| | - Helder Maiato
- a Chromosome Instability & Dynamics Laboratory; Instituto de Biologia Molecular e Celular; Universidade do Porto ; Porto , Portugal.,b Instituto de Investigação e Inovação em Saúde - i3S; Universidade do Porto ; Portugal.,c Cell Division Unit ; Department of Experimental Biology; Faculdade de Medicina; Universidade do Porto ; Porto , Portugal
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16
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Mary H, Fouchard J, Gay G, Reyes C, Gauthier T, Gruget C, Pécréaux J, Tournier S, Gachet Y. Fission yeast kinesin-8 controls chromosome congression independently of oscillations. J Cell Sci 2015; 128:3720-30. [PMID: 26359299 PMCID: PMC4631777 DOI: 10.1242/jcs.160465] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 09/03/2015] [Indexed: 01/09/2023] Open
Abstract
In higher eukaryotes, efficient chromosome congression relies, among other players, on the activity of chromokinesins. Here, we provide a quantitative analysis of kinetochore oscillations and positioning in Schizosaccharomyces pombe, a model organism lacking chromokinesins. In wild-type cells, chromosomes align during prophase and, while oscillating, maintain this alignment throughout metaphase. Chromosome oscillations are dispensable both for kinetochore congression and stable kinetochore alignment during metaphase. In higher eukaryotes, kinesin-8 family members control chromosome congression by regulating their oscillations. By contrast, here, we demonstrate that fission yeast kinesin-8 controls chromosome congression by an alternative mechanism. We propose that kinesin-8 aligns chromosomes by controlling pulling forces in a length-dependent manner. A coarse-grained model of chromosome segregation implemented with a length-dependent process that controls the force at kinetochores is necessary and sufficient to mimic kinetochore alignment, and prevents the appearance of lagging chromosomes. Taken together, these data illustrate how the local action of a motor protein at kinetochores provides spatial cues within the spindle to align chromosomes and to prevent aneuploidy. Highlighted Article: Quantitative analysis in S. pombe reveals that chromosome oscillations are dispensable for kinetochore congression in mitosis. Kinesin-8 controls chromosome congression through length-dependent pulling forces.
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Affiliation(s)
- Hadrien Mary
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Jonathan Fouchard
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Guillaume Gay
- DAMCB, 43 rue Horace Bertin, Marseille 13005, France
| | - Céline Reyes
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Tiphaine Gauthier
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Clémence Gruget
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Jacques Pécréaux
- IGDR, Institute of Genetics and Development of Rennes, University Rennes 1, Rennes F-35043, France
| | - Sylvie Tournier
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Yannick Gachet
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
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McCoy KM, Tubman ES, Claas A, Tank D, Clancy SA, O'Toole ET, Berman J, Odde DJ. Physical limits on kinesin-5-mediated chromosome congression in the smallest mitotic spindles. Mol Biol Cell 2015; 26:3999-4014. [PMID: 26354423 PMCID: PMC4710232 DOI: 10.1091/mbc.e14-10-1454] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 09/03/2015] [Indexed: 12/13/2022] Open
Abstract
A characteristic feature of mitotic spindles is the congression of chromosomes near the spindle equator, a process mediated by dynamic kinetochore microtubules. A major challenge is to understand how precise, submicrometer-scale control of kinetochore micro-tubule dynamics is achieved in the smallest mitotic spindles, where the noisiness of microtubule assembly/disassembly will potentially act to overwhelm the spatial information that controls microtubule plus end-tip positioning to mediate congression. To better understand this fundamental limit, we conducted an integrated live fluorescence, electron microscopy, and modeling analysis of the polymorphic fungal pathogen Candida albicans, which contains one of the smallest known mitotic spindles (<1 μm). Previously, ScCin8p (kinesin-5 in Saccharomyces cerevisiae) was shown to mediate chromosome congression by promoting catastrophe of long kinetochore microtubules (kMTs). Using C. albicans yeast and hyphal kinesin-5 (Kip1p) heterozygotes (KIP1/kip1∆), we found that mutant spindles have longer kMTs than wild-type spindles, consistent with a less-organized spindle. By contrast, kinesin-8 heterozygous mutant (KIP3/kip3∆) spindles exhibited the same spindle organization as wild type. Of interest, spindle organization in the yeast and hyphal states was indistinguishable, even though yeast and hyphal cell lengths differ by two- to fivefold, demonstrating that spindle length regulation and chromosome congression are intrinsic to the spindle and largely independent of cell size. Together these results are consistent with a kinesin-5-mediated, length-dependent depolymerase activity that organizes chromosomes at the spindle equator in C. albicans to overcome fundamental noisiness in microtubule self-assembly. More generally, we define a dimensionless number that sets a fundamental physical limit for maintaining congression in small spindles in the face of assembly noise and find that C. albicans operates very close to this limit, which may explain why it has the smallest known mitotic spindle that still manifests the classic congression architecture.
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Affiliation(s)
- Kelsey M McCoy
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
| | - Emily S Tubman
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
| | - Allison Claas
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
| | - Damien Tank
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Shelly Applen Clancy
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Eileen T O'Toole
- Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309 Boulder Laboratory for 3D Electron Microscopy of Cells, University of Colorado at Boulder, Boulder, CO 80309
| | - Judith Berman
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455 Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - David J Odde
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
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18
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Gasic I, Nerurkar P, Meraldi P. Centrosome age regulates kinetochore-microtubule stability and biases chromosome mis-segregation. eLife 2015; 4. [PMID: 26287477 PMCID: PMC4579388 DOI: 10.7554/elife.07909] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 08/18/2015] [Indexed: 12/21/2022] Open
Abstract
The poles of the mitotic spindle contain one old and one young centrosome. In asymmetric stem cell divisions, the age of centrosomes affects their behaviour and their probability to remain in the stem cell. In contrast, in symmetric divisions, old and young centrosomes are thought to behave equally. This hypothesis is, however, untested. In this study, we show in symmetrically dividing human cells that kinetochore-microtubules associated to old centrosomes are more stable than those associated to young centrosomes, and that this difference favours the accumulation of premature end-on attachments that delay the alignment of polar chromosomes at old centrosomes. This differential microtubule stability depends on cenexin, a protein enriched on old centrosomes. It persists throughout mitosis, biasing chromosome segregation in anaphase by causing daughter cells with old centrosomes to retain non-disjoint chromosomes 85% of the time. We conclude that centrosome age imposes via cenexin a functional asymmetry on all mitotic spindles.
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Affiliation(s)
- Ivana Gasic
- Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Purnima Nerurkar
- Institute of Biochemistry, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Patrick Meraldi
- Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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19
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Muscat CC, Torre-Santiago KM, Tran MV, Powers JA, Wignall SM. Kinetochore-independent chromosome segregation driven by lateral microtubule bundles. eLife 2015; 4:e06462. [PMID: 26026148 PMCID: PMC4481507 DOI: 10.7554/elife.06462] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 05/28/2015] [Indexed: 12/17/2022] Open
Abstract
During cell division, chromosomes attach to spindle microtubules at sites called kinetochores, and force generated at the kinetochore-microtubule interface is the main driver of chromosome movement. Surprisingly, kinetochores are not required for chromosome segregation on acentrosomal spindles in Caenorhabditis elegans oocytes, but the mechanism driving chromosomes apart in their absence is not understood. In this study, we show that lateral microtubule–chromosome associations established during prometaphase remain intact during anaphase to facilitate separation, defining a novel form of kinetochore-independent segregation. Chromosome dynamics during congression and segregation are controlled by opposing forces; plus-end directed forces are mediated by a protein complex that forms a ring around the chromosome center and dynein on chromosome arms provides a minus-end force. At anaphase onset, ring removal shifts the balance between these forces, triggering poleward movement along lateral microtubule bundles. This represents an elegant strategy for controlling chromosomal movements during cell division distinct from the canonical kinetochore-driven mechanism. DOI:http://dx.doi.org/10.7554/eLife.06462.001 An animal's genetic material is packaged into structures called chromosomes. Most animals have two sets of chromosomes: one from each parent. Sperm and egg cells must contain half the number of chromosomes compared to other cells in the body, so that when they fuse, the resulting embryo receives a full complement of chromosomes. Egg and sperm cells are made via a type of cell division called meiosis. In meiosis, the genetic material of a cell is copied once but then the cell divides twice. Therefore, at the end of the two divisions, the resulting sperm or egg cells contain half the number of chromosomes as the original cell. During cell division, the genetic material is separated by a structure called the spindle apparatus. The spindle is made of protein filaments called microtubules. At each end of the spindle, there is a cluster of microtubule ends, known as a ‘pole’. The other ends of the microtubules extend out towards the center of the spindle, where they overlap with the microtubules from the opposite pole. The chromosomes line up in the center of the spindle and then the chromosomes are separated, with half moving to one spindle pole, and half to the other. In most forms of cell division, the microtubules attach to the chromosomes via sites called kinetochores. However, it was recently discovered that kinetochores are not required to separate chromosomes to make egg cells in the worm C. elegans, suggesting that these chromosomes associate with the spindle in a different way. Muscat, Torre-Santiago et al. have now used high-resolution imaging to look at this chromosome separation process in more detail and to figure out how the chromosomes separate when C. elegans forms egg cells. The experiments revealed that the chromosomes move within the spindle along parallel microtubule bundles, much like trains moving along a track. The chromosomes are moved into position at the center of the spindle by a ring-shaped group (or ‘complex’) of proteins that forms around the center of each chromosome. The protein complex comes off the chromosomes as they separate, and a motor protein called dynein walks along the microtubules to pull the separated chromosomes to the poles. Muscat, Torre-Santiago et al.'s findings thus show that meiosis in C. elegans during the production of egg cells works in a very different way to other types of cell division. In the future, it will be important to understand how dynein and the ring-shaped complex are regulated, as this may shed light on what causes mistakes in the separation of genetic material during meiosis, which can lead to infertility, miscarriages, and birth defects in humans and other animals. DOI:http://dx.doi.org/10.7554/eLife.06462.002
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Affiliation(s)
- Christina C Muscat
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | | | - Michael V Tran
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - James A Powers
- Light Microscopy Imaging Center, Indiana University, Bloomington, United States
| | - Sarah M Wignall
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
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20
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Bancroft J, Auckland P, Samora CP, McAinsh AD. Chromosome congression is promoted by CENP-Q- and CENP-E-dependent pathways. J Cell Sci 2015; 128:171-84. [PMID: 25395579 PMCID: PMC4282051 DOI: 10.1242/jcs.163659] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/03/2014] [Indexed: 01/29/2023] Open
Abstract
A key step of mitosis is the congression of chromosomes to the spindle equator. Congression is driven by at least two distinct mechanisms: (1) kinetochores slide along the microtubule lattice using the plus-end directed CENP-E motor, and (2) kinetochores biorientating near the pole move to the equator through microtubule depolymerisation-coupled pulling. Here, we show that CENP-Q - a subunit of the CENP-O complex (comprising CENP-O, CENP-P, CENP-Q and CENP-U) that targets polo-like kinase (Plk1) to kinetochores - is also required for the recruitment of CENP-E to kinetochores. We further reveal a CENP-E recruitment-independent role for CENP-Q in depolymerisation-coupled pulling. Both of these functions are abolished by a single point mutation in CENP-Q (S50A) - a residue that is phosphorylated in vivo. Importantly, the S50A mutant does not affect the loading of Plk1 onto kinetochores and leaves the CENP-O complex intact. Thus, the functions of CENP-Q in CENP-E loading and depolymerisation-coupled pulling are independent from its role in Plk1 recruitment and CENP-O complex stabilisation. Taken together, our data provide evidence that phosphoregulation of CENP-Q plays a central function in coordinating chromosome congression mechanisms.
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Affiliation(s)
- James Bancroft
- Mechanochemical Cell Biology Building, Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Philip Auckland
- Mechanochemical Cell Biology Building, Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Catarina P Samora
- Mechanochemical Cell Biology Building, Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Andrew D McAinsh
- Mechanochemical Cell Biology Building, Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
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21
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Matson DR, Stukenberg PT. CENP-I and Aurora B act as a molecular switch that ties RZZ/Mad1 recruitment to kinetochore attachment status. ACTA ACUST UNITED AC 2014; 205:541-54. [PMID: 24862574 PMCID: PMC4033774 DOI: 10.1083/jcb.201307137] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The integrated activities of Aurora B and CENP-I generate a molecular switch that maintains a robust spindle checkpoint signal at prometaphase kinetochores until they attain mature attachments to microtubules. The RZZ (Rod, ZW10, and Zwilch) complex and Mad1 proteins tightly associate with kinetochores to generate the spindle checkpoint signal, but they are released when a kinetochore forms mature microtubule attachments. Here we demonstrate that the centromere protein CENP-I is required to generate a stable association of RZZ and Mad1 with kinetochores. CENP-I also inhibits their removal by dynein stripping. This regulation of Mad1 and RZZ dissociation functions independently of Aurora B, which regulates their association. We show that the microtubule status of each kinetochore independently dictates the recruitment of Aurora B kinase, kinase activity on a kinetochore substrate, and loading of spindle checkpoint proteins. This dynamic regulation of Mad1 association by Aurora B is only uncovered when CENP-I is depleted, consistent with our finding that CENP-I inhibits the dissociation of Mad1. We conclude that the dual activities of Aurora B and CENP-I generate a molecular switch that maintains a robust spindle checkpoint signal at prometaphase kinetochores until they attain mature attachments to microtubules.
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Affiliation(s)
- Daniel R Matson
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - P Todd Stukenberg
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908
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22
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Xu P, Virshup DM, Lee SH. B56-PP2A regulates motor dynamics for mitotic chromosome alignment. J Cell Sci 2014; 127:4567-73. [PMID: 25179604 DOI: 10.1242/jcs.154609] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Proper alignment of duplicated chromosomes at the metaphase plate involves both motor-driven chromosome movement and the functional and physical end-on connection (K-fiber formation) between the kinetochore and the plus-end of microtubules. The B56 family of protein phosphatase 2A (PP2A) regulatory subunits (B56-PP2A), through their interaction with the mitotic checkpoint protein BUBR1, are required for proper chromosome alignment, but the underlying mechanism(s) has remained elusive. Here, we show that B56-PP2A promotes chromosome alignment primarily by balancing chromosome movement towards the metaphase plate, rather than by directly establishing stable K-fibers. Notably, the poleward movement of chromosomes in cells depleted of the B56 family can be rescued by depletion of HSET (also known as kinesin-14 or KIFC1), a major minus-end-directed motor protein. Strikingly, K-fiber formation can be restored if chromosome movement to the metaphase plate is rescued in B56-depleted cells. Furthermore, the B56-BUBR1 interaction is required for promoting motor-driven chromosome movement towards the metaphase plate. Thus, we propose that B56-PP2A functions in mitotic chromosome alignment by balancing chromosome movement towards the metaphase plate, which is essential for the subsequent establishment of stable and functional kinetochore-microtubule attachments, and mitotic exit.
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Affiliation(s)
- Peng Xu
- Program in Cancer & Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore, 8 College Road, Singapore 169857, Singapore NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, Singapore 117456, Singapore
| | - David M Virshup
- Program in Cancer & Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore, 8 College Road, Singapore 169857, Singapore
| | - Sang Hyun Lee
- Program in Cancer & Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore, 8 College Road, Singapore 169857, Singapore
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23
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Bissonette S, Stumpff J. Quantifying Mitotic Chromosome Dynamics and Positioning. J Cell Physiol 2014; 229:1301-5. [PMID: 24683081 DOI: 10.1002/jcp.24634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 03/26/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Samantha Bissonette
- Department of Molecular Physiology and Biophysics; University of Vermont; Burlington Vermont
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics; University of Vermont; Burlington Vermont
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24
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Weng MT, Luo J. The enigmatic ERH protein: its role in cell cycle, RNA splicing and cancer. Protein Cell 2014; 4:807-12. [PMID: 24078386 DOI: 10.1007/s13238-013-3056-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 08/26/2013] [Indexed: 12/21/2022] Open
Abstract
Enhancer of rudimentary homolog (ERH) is a small, highly conserved protein among eukaryotes. Since its discovery nearly 20 years ago, its molecular function has remained enigmatic. It has been implicated to play a role in transcriptional regulation and in cell cycle. We recently showed that ERH binds to the Sm complex and is required for the mRNA splicing of the mitotic motor protein CENP-E. Furthermore, cancer cells driven by mutations in the KRAS oncogene are particularly sensitive to RNAi-mediated suppression of ERH function, and ERH expression is inversely correlated with survival in colorectal cancer patients whose tumors harbor KRAS mutation. These recent findings indicate that ERH plays an important role in cell cycle through its mRNA splicing activity and is critically required for genomic stability and cancer cell survival.
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25
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Shrestha RL, Tamura N, Fries A, Levin N, Clark J, Draviam VM. TAO1 kinase maintains chromosomal stability by facilitating proper congression of chromosomes. Open Biol 2014; 4:130108. [PMID: 24898139 PMCID: PMC4077056 DOI: 10.1098/rsob.130108] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 05/09/2014] [Indexed: 12/19/2022] Open
Abstract
Chromosomal instability can arise from defects in chromosome-microtubule attachment. Using a variety of drug treatments, we show that TAO1 kinase is required for ensuring the normal congression of chromosomes. Depletion of TAO1 reduces the density of growing interphase and mitotic microtubules in human cells, showing TAO1's role in controlling microtubule dynamics. We demonstrate the aneugenic nature of chromosome-microtubule attachment defects in TAO1-depleted cells using an error-correction assay. Our model further strengthens the emerging paradigm that microtubule regulatory pathways are important for resolving erroneous kinetochore-microtubule attachments and maintaining the integrity of the genome, regardless of the spindle checkpoint status.
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Affiliation(s)
- Roshan L Shrestha
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Naoka Tamura
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Anna Fries
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Nicolas Levin
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Joanna Clark
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Viji M Draviam
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
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26
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Cross RA, McAinsh A. Prime movers: the mechanochemistry of mitotic kinesins. Nat Rev Mol Cell Biol 2014; 15:257-71. [PMID: 24651543 DOI: 10.1038/nrm3768] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation.
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Affiliation(s)
- Robert A Cross
- Warwick Medical School, Gibbet Hill, Coventry CV4 7AL, UK
| | - Andrew McAinsh
- Warwick Medical School, Gibbet Hill, Coventry CV4 7AL, UK
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27
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Caldas GV, DeLuca JG. KNL1: bringing order to the kinetochore. Chromosoma 2013; 123:169-81. [PMID: 24310619 DOI: 10.1007/s00412-013-0446-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 11/30/2022]
Abstract
KNL1 is an evolutionarily conserved kinetochore-associated protein essential for accurate chromosome segregation in eukaryotic cells. This large scaffold protein, predicted to be almost entirely unstructured, is involved in diverse mitotic processes including kinetochore assembly, chromosome congression, and mitotic checkpoint signaling. How this kinetochore "hub" coordinates protein-protein interactions spatially and temporally during mitosis to orchestrate these processes is an area of active investigation. Here we summarize the current understanding of KNL1 and discuss possible mechanisms by which this protein actively contributes to multiple aspects of mitotic progression.
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Affiliation(s)
- Gina V Caldas
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
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28
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Zhang B, Li KY, Chen HY, Pan SD, Jiang LC, Wu YP, Liu SW. Spindle and kinetochore associated complex subunit 1 regulates the proliferation of oral adenosquamous carcinoma CAL-27 cells in vitro. Cancer Cell Int 2013; 13:83. [PMID: 23962337 PMCID: PMC3765658 DOI: 10.1186/1475-2867-13-83] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 08/19/2013] [Indexed: 12/15/2022] Open
Abstract
Background The prognosis of oral squamous cell carcinoma is very poor due to local recurrence and metastasis. This study explores the molecular events involved in oral carcinoma with the goal of developing novel therapeutic strategies. The mitotic spindle is a complex mechanical apparatus required for the accurate segregation of sister chromosomes during mitosis. Spindle and kinetochore associated complex subunit 1 (SKA1) is a microtubule-binding subcomplex of the outer kinetochore that is essential for proper chromosome segregation. In recent years, much attention has been focused on determining how SKA proteins interact with each other, as well as their biological role in cancer cells. However, the precise role of SKA1 in oral carcinoma remains unknown. Methods In order to investigate the role of SKA1 in oral cancer, we employed lentivirus-mediated shRNA to silence SKA1 expression in the CAL-27 human oral adenosquamous carcinoma cell line. Results Depletion of SKA1 in CAL-27 cells significantly decreased cell proliferation, as determined by MTT and colony formation assays. These results strongly demonstrate that reduced SKA1 protein levels may cause inhibition of tumor formation. The shRNA-mediated depletion of SKA1 also led to G2/M phase cell cycle arrest and apoptosis. Conclusion This is the first report to show that SKA1 plays an important role in the progression of oral adenosqamous carcinoma. Thus, silencing of SKA1 by RNAi might be a potential therapy for this disease.
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Affiliation(s)
- Bin Zhang
- Department of Anatomy, Shandong University, School of Medicine, Jinan, Shandong 250012, P, R, China.
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29
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Evolutionarily conserved protein ERH controls CENP-E mRNA splicing and is required for the survival of KRAS mutant cancer cells. Proc Natl Acad Sci U S A 2012; 109:E3659-67. [PMID: 23236152 DOI: 10.1073/pnas.1207673110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Cancers with Ras mutations represent a major therapeutic problem. Recent RNAi screens have uncovered multiple nononcogene addiction pathways that are necessary for the survival of Ras mutant cells. Here, we identify the evolutionarily conserved gene enhancer of rudimentary homolog (ERH), in which depletion causes greater toxicity in cancer cells with mutations in the small GTPase KRAS compared with KRAS WT cells. ERH interacts with the spliceosome protein SNRPD3 and is required for the mRNA splicing of the mitotic motor protein CENP-E. Loss of ERH leads to loss of CENP-E and consequently, chromosome congression defects. Gene expression profiling indicates that ERH is required for the expression of multiple cell cycle genes, and the gene expression signature resulting from ERH down-regulation inversely correlates with KRAS signatures. Clinically, tumor ERH expression is inversely associated with survival of colorectal cancer patients whose tumors harbor KRAS mutations. Together, these findings identify a role of ERH in mRNA splicing and mitosis, and they provide evidence that KRAS mutant cancer cells are dependent on ERH for their survival.
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30
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Gay G, Courtheoux T, Reyes C, Tournier S, Gachet Y. A stochastic model of kinetochore-microtubule attachment accurately describes fission yeast chromosome segregation. ACTA ACUST UNITED AC 2012; 196:757-74. [PMID: 22412019 PMCID: PMC3308688 DOI: 10.1083/jcb.201107124] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In fission yeast, erroneous attachments of spindle microtubules to kinetochores are frequent in early mitosis. Most are corrected before anaphase onset by a mechanism involving the protein kinase Aurora B, which destabilizes kinetochore microtubules (ktMTs) in the absence of tension between sister chromatids. In this paper, we describe a minimal mathematical model of fission yeast chromosome segregation based on the stochastic attachment and detachment of ktMTs. The model accurately reproduces the timing of correct chromosome biorientation and segregation seen in fission yeast. Prevention of attachment defects requires both appropriate kinetochore orientation and an Aurora B-like activity. The model also reproduces abnormal chromosome segregation behavior (caused by, for example, inhibition of Aurora B). It predicts that, in metaphase, merotelic attachment is prevented by a kinetochore orientation effect and corrected by an Aurora B-like activity, whereas in anaphase, it is corrected through unbalanced forces applied to the kinetochore. These unbalanced forces are sufficient to prevent aneuploidy.
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Affiliation(s)
- Guillaume Gay
- Laboratoire de biologie cellulaire et moléculaire du contrôle de la proliferation, Université de Toulouse, F-31062 Toulouse, France
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McHedlishvili N, Wieser S, Holtackers R, Mouysset J, Belwal M, Amaro AC, Meraldi P. Kinetochores accelerate centrosome separation to ensure faithful chromosome segregation. J Cell Sci 2012; 125:906-18. [PMID: 22399803 DOI: 10.1242/jcs.091967] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
At the onset of mitosis, cells need to break down their nuclear envelope, form a bipolar spindle and attach the chromosomes to microtubules via kinetochores. Previous studies have shown that spindle bipolarization can occur either before or after nuclear envelope breakdown. In the latter case, early kinetochore-microtubule attachments generate pushing forces that accelerate centrosome separation. However, until now, the physiological relevance of this prometaphase kinetochore pushing force was unknown. We investigated the depletion phenotype of the kinetochore protein CENP-L, which we find to be essential for the stability of kinetochore microtubules, for a homogenous poleward microtubule flux rate and for the kinetochore pushing force. Loss of this force in prometaphase not only delays centrosome separation by 5-6 minutes, it also causes massive chromosome alignment and segregation defects due to the formation of syntelic and merotelic kinetochore-microtubule attachments. By contrast, CENP-L depletion has no impact on mitotic progression in cells that have already separated their centrosomes at nuclear envelope breakdown. We propose that the kinetochore pushing force is an essential safety mechanism that favors amphitelic attachments by ensuring that spindle bipolarization occurs before the formation of the majority of kinetochore-microtubule attachments.
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Affiliation(s)
- Nunu McHedlishvili
- Institute of Biochemistry, ETH Zurich, Schafmattstrasse 18, 8093 Zürich, Switzerland
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32
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Abstract
Mitosis is the process by which eukaryotic cells organize and segregate their chromosomes in preparation for cell division. It is accomplished by a cellular machine composed largely of microtubules (MTs) and their associated proteins. This article reviews literature on mitosis from a biophysical point of view, drawing attention to the assembly and motility processes required to do this complex job with precision. Work from both the recent and the older literature is integrated into a description of relevant biological events and the experiments that probe their mechanisms. Theoretical work on specific subprocesses is also reviewed. Our goal is to provide a document that will expose biophysicists to the fascination of this quite amazing process and provide them with a good background from which they can pursue their own research interests in the subject.
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Bolanos-Garcia VM, Nilsson J, Blundell TL. The architecture of the BubR1 tetratricopeptide tandem repeat defines a protein motif underlying mitotic checkpoint-kinetochore communication. BIOARCHITECTURE 2012; 2:23-27. [PMID: 22754625 PMCID: PMC3383715 DOI: 10.4161/bioa.19932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The accurate and timely transmission of the genetic material to progeny during successive rounds of cell division is sine qua non for the maintenance of genome stability. Eukaryotic cells have evolved a surveillance mechanism, the mitotic spindle assembly checkpoint (SAC), to prevent premature advance to anaphase before every chromosome is properly attached to microtubules of the mitotic spindle. The architecture of the KNL1-BubR1 complex reveals important features of the molecular recognition between SAC components and the kinetochore. The interaction is important for a functional SAC as substitution of BubR1 residues engaged in KNL1 binding impaired the SAC and BubR1 recruitment into checkpoint complexes in stable cell lines. Here we discuss the implications of the disorder-to-order transition of KNL1 upon BubR1 binding for SAC signaling and propose a mechanistic model of how BUBs binding may affect the recognition of KNL1 by its other interacting partners.
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McAinsh AD, Meraldi P. The CCAN complex: Linking centromere specification to control of kinetochore–microtubule dynamics. Semin Cell Dev Biol 2011; 22:946-52. [DOI: 10.1016/j.semcdb.2011.09.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 09/29/2011] [Indexed: 12/20/2022]
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Meraldi P. Keeping kinetochores on track. Eur J Cell Biol 2011; 91:103-6. [PMID: 22104445 DOI: 10.1016/j.ejcb.2011.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 10/06/2011] [Indexed: 11/26/2022] Open
Abstract
The multiple functions of kinetochores are reflected in their complex composition, with over a hundred different proteins, which self-associate in several functional subcomplexes. Most of these kinetochore proteins were identified over the last 10-12 years using a combination of genetic, cell biological, biochemical, and bioinformatic approaches in various model organisms. The key challenge since then has been to determine the structural architecture of kinetochores, define the functions of its different subcomponents, and understand its regulation, both in response to the rapid changes in microtubule dynamics or to sense erroneous attachments for spindle checkpoint signalling. Here, we present some of the key advances obtained in the last six years on the biology of kinetochores, both through our work and through the work of many other groups studying this exciting structure.
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Affiliation(s)
- Patrick Meraldi
- Institute of Biochemistry, ETH Zurich, Schafmattstrasse 18, CH-8093 Zurich, Switzerland.
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Meunier S, Vernos I. K-fibre minus ends are stabilized by a RanGTP-dependent mechanism essential for functional spindle assembly. Nat Cell Biol 2011; 13:1406-14. [PMID: 22081094 DOI: 10.1038/ncb2372] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 09/30/2011] [Indexed: 02/07/2023]
Abstract
Chromosome segregation requires the formation of K-fibres, microtubule bundles that attach sister kinetochores to spindle poles. Most K-fibre microtubules originate around the chromosomes through a non-centrosomal RanGTP-dependent pathway and become oriented with the plus ends attached to the kinetochore and the minus ends focused at the spindle poles. The capture and stabilization of microtubule plus ends at the kinetochore has been extensively studied but very little is known on how their minus-end dynamics are controlled. Here we show that MCRS1 is a RanGTP-regulated factor essential for non-centrosomal microtubule assembly. MCRS1 localizes to the minus ends of chromosomal microtubules and K-fibres, where it protects them from depolymerization. Our data reveal the existence of a mechanism that stabilizes the minus ends of chromosomal microtubules and K-fibres, and is essential for the assembly of a functional bipolar spindle.
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Affiliation(s)
- Sylvain Meunier
- Cell and Developmental Biology Program, Centre for Genomic Regulation, Universitat Pompeu Fabra, 08003 Barcelona, Spain
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Silva P, Barbosa J, Nascimento AV, Faria J, Reis R, Bousbaa H. Monitoring the fidelity of mitotic chromosome segregation by the spindle assembly checkpoint. Cell Prolif 2011; 44:391-400. [PMID: 21951282 DOI: 10.1111/j.1365-2184.2011.00767.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Accurate chromosome segregation relies on activity of the spindle assembly checkpoint, a surveillance mechanism that prevents premature anaphase onset until all chromosomes are properly attached to the mitotic spindle apparatus and aligned at the metaphase plate. Defects in this mechanism contribute to chromosome instability and aneuploidy, a hallmark of malignant cells. Here, we review the molecular mechanisms of activation and silencing of the spindle assembly checkpoint and its relationship to tumourigenesis.
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Affiliation(s)
- P Silva
- Health Sciences Research Center, Superior Institute of Health Sciences - North, CESPU, Gandra PRD, Portugal
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Kitajima TS, Ohsugi M, Ellenberg J. Complete kinetochore tracking reveals error-prone homologous chromosome biorientation in mammalian oocytes. Cell 2011; 146:568-81. [PMID: 21854982 DOI: 10.1016/j.cell.2011.07.031] [Citation(s) in RCA: 231] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 05/17/2011] [Accepted: 07/25/2011] [Indexed: 10/17/2022]
Abstract
Chromosomes must establish stable biorientation prior to anaphase to achieve faithful segregation during cell division. The detailed process by which chromosomes are bioriented and how biorientation is coordinated with spindle assembly and chromosome congression remain unclear. Here, we provide complete 3D kinetochore-tracking datasets throughout cell division by high-resolution imaging of meiosis I in live mouse oocytes. We show that in acentrosomal oocytes, chromosome congression forms an intermediate chromosome configuration, the prometaphase belt, which precedes biorientation. Chromosomes then invade the elongating spindle center to form the metaphase plate and start biorienting. Close to 90% of all chromosomes undergo one or more rounds of error correction of their kinetochore-microtubule attachments before achieving correct biorientation. This process depends on Aurora kinase activity. Our analysis reveals the error-prone nature of homologous chromosome biorientation, providing a possible explanation for the high incidence of aneuploid eggs observed in mammals, including humans.
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Affiliation(s)
- Tomoya S Kitajima
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, Heidelberg D-69117, Germany
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Vladimirou E, Harry E, Burroughs N, McAinsh AD. Springs, clutches and motors: driving forward kinetochore mechanism by modelling. Chromosome Res 2011; 19:409-21. [PMID: 21331796 PMCID: PMC3078324 DOI: 10.1007/s10577-011-9191-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
As a mechanical system, the kinetochore can be viewed as a set of interacting springs, clutches and motors; the problem of kinetochore mechanism is now one of understanding how these functional modules assemble, disassemble and interact with one another to give rise to the emergent properties of the system. The sheer complexity of the kinetochore system points to a future requirement for data-driven mathematical modelling and statistical analysis based on quantitative empirical measurement of sister kinetochore trajectories. Here, we review existing models of chromosome motion in the context of recent advances in our understanding of kinetochore molecular biology.
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Affiliation(s)
- Elina Vladimirou
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, UK
| | - Ed Harry
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, UK
- Molecular Organisation and Assembly in Cells (MOAC) Doctoral Training Centre, University of Warwick, Coventry, UK
- Warwick Systems Biology Centre, University of Warwick, Coventry, UK
| | - Nigel Burroughs
- Warwick Systems Biology Centre, University of Warwick, Coventry, UK
| | - Andrew D. McAinsh
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, UK
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Jiang K, Akhmanova A. Microtubule tip-interacting proteins: a view from both ends. Curr Opin Cell Biol 2011; 23:94-101. [PMID: 20817499 DOI: 10.1016/j.ceb.2010.08.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 08/08/2010] [Indexed: 10/19/2022]
Abstract
Microtubule ends serve as sites of tubulin addition and removal, and at the same time play crucial roles in microtubule capture, stabilization and attachment to different cellular structures. Microtubule plus and minus-ends possess distinct structural and dynamic properties, and are recognized, bound and regulated by diverse factors. These include specific capping factors such as γ-tubulin, motors, such as plus-end and minus-end directed kinesins, highly specialized kinetochore-bound microtubule-associated proteins, and comet-making plus-end tracking proteins such as EB1 and its partners. Here, we provide an overview of microtubule tip-interacting proteins and the mechanisms responsible for their association with microtubule ends, and discuss the functional cross-talk between microtubule plus and minus-end binding factors.
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Affiliation(s)
- Kai Jiang
- Department of Cell Biology, Erasmus Medical Center, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
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41
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Abstract
In each cell division, the newly duplicated chromosomes must be evenly distributed between the sister cells. Errors in this process during meiosis or mitosis are equally fatal: improper segregation of the chromosome 21 during human meiosis leads to Down syndrome (Conley, Aneuploidy: etiology and mechanisms, pp 35-89, 1985), whereas in somatic cells, aneuploidy has been linked to carcinogenesis, by unbalancing the ratio of oncogenes and tumor suppressors (Holland and Cleveland, Nat Rev Mol Cell Biol 10(7):478-487, 2009; Yuen et al., Curr Opin Cell Biol 17(6):576-582, 2005). Eukaryotic cells have developed a mechanism, known as the spindle assembly checkpoint, to detect erroneous attachment of chromosomes to the mitotic/meiotic spindle and delay the cell cycle to give enough time to resolve these defects. Research in the last 20 years, has demonstrated that the spindle assembly checkpoint is not only a pure checkpoint pathway, but plays a constitutive role in every cell cycle. Here, we review our current knowledge of how the spindle assembly checkpoint is integrated into the cell cycle machinery, and discuss some of the questions that have to be addressed in the future.
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Kinetochore-microtubule interactions: steps towards bi-orientation. EMBO J 2010; 29:4070-82. [PMID: 21102558 DOI: 10.1038/emboj.2010.294] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Accepted: 10/29/2010] [Indexed: 11/08/2022] Open
Abstract
Eukaryotic cells segregate their chromosomes accurately to opposite poles during mitosis, which is necessary for maintenance of their genetic integrity. This process mainly relies on the forces generated by kinetochore-microtubule (KT-MT) attachment. During prometaphase, the KT initially interacts with a single MT extending from a spindle pole and then moves towards a spindle pole. Subsequently, MTs from the other spindle pole also interact with the KT. Eventually, one sister KT becomes attached to MTs from one pole while the other sister to those from the other pole (sister KT bi-orientation). If sister KTs interact with MTs with aberrant orientation, this must be corrected to attain proper bi-orientation (error correction) before the anaphase is initiated. Here, I discuss how KTs initially interact with MTs and how this interaction develops into bi-orientation; both processes are fundamentally crucial for proper chromosome segregation in the subsequent anaphase.
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Drosophila Mis12 complex acts as a single functional unit essential for anaphase chromosome movement and a robust spindle assembly checkpoint. Genetics 2010; 187:131-40. [PMID: 20980244 DOI: 10.1534/genetics.110.119628] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The kinetochore is a dynamic multiprotein complex assembled at the centromere in mitosis. Exactly how the structure of the kinetochore changes during mitosis and how its individual components contribute to chromosome segregation is largely unknown. Here we have focused on the contribution of the Mis12 complex to kinetochore assembly and function throughout mitosis in Drosophila. We show that despite the sequential kinetochore recruitment of Mis12 complex subunits Mis12 and Nsl1, the complex acts as a single functional unit. mis12 and nsl1 mutants show strikingly similar developmental and mitotic defects in which chromosomes are able to congress at metaphase, but their anaphase movement is strongly affected. While kinetochore association of Ndc80 absolutely depends on both Mis12 and Nsl1, BubR1 localization shows only partial dependency. In the presence of residual centromeric BubR1 the checkpoint still responds to microtubule depolymerization but is significantly weaker. These observations point to a complexity of the checkpoint response that may reflect subpopulations of BubR1 associated with residual kinetochore components, the core centromere, or elsewhere in the cell. Importantly our results indicate that core structural elements of the inner plate of the kinetochore have a greater contribution to faithful chromosome segregation in anaphase than in earlier stages of mitosis.
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Gouveia SM, Akhmanova A. Cell and Molecular Biology of Microtubule Plus End Tracking Proteins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 285:1-74. [DOI: 10.1016/b978-0-12-381047-2.00001-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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