101
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Cao JY, Liu L, Chen SP, Zhang X, Mi YJ, Liu ZG, Li MZ, Zhang H, Qian CN, Shao JY, Fu LW, Xia YF, Zeng MS. Prognostic significance and therapeutic implications of centromere protein F expression in human nasopharyngeal carcinoma. Mol Cancer 2010; 9:237. [PMID: 20828406 PMCID: PMC2944187 DOI: 10.1186/1476-4598-9-237] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 09/09/2010] [Indexed: 02/04/2023] Open
Abstract
Background Our recent cDNA microarray data showed that centromere protein F (CENP-F) is significantly upregulated in primary cultured nasopharyngeal carcinoma (NPC) tumor cells compared with normal nasopharyngeal epithelial cells. The goal of this study was to further investigate the levels of CENP-F expression in NPC cell lines and tissues to clarify the clinical significance of CENP-F expression in NPC as well as the potential therapeutic implications of CENP-F expression. Methods Real-time RT-PCR and western blotting were used to examine CENP-F expression levels in normal primary nasopharyngeal epithelial cells (NPEC), immortalized nasopharyngeal epithelial cells and NPC cell lines. Levels of CENP-F mRNA were determined by real-time RT-PCR in 23 freshly frozen nasopharyngeal biopsy tissues, and CENP-F protein levels were detected by immunohistochemistry in paraffin sections of 202 archival NPC tissues. Statistical analyses were applied to test for prognostic associations. The cytotoxicities of CENP-F potential target chemicals, zoledronic acid (ZOL) and FTI-277 alone, or in combination with cisplatin, in NPC cells were determined by the MTT assay. Results The levels of CENP-F mRNA and protein were higher in NPC cell lines than in normal and immortalized NPECs. CENP-F mRNA level was upregulated in nasopharyngeal carcinoma biopsy tissues compared with noncancerous tissues. By immunohistochemical analysis, CENP-F was highly expressed in 98 (48.5%) of 202 NPC tissues. Statistical analysis showed that high expression of CENP-F was positively correlated with T classification (P < 0.001), clinical stage (P < 0.001), skull-base invasion (P < 0.001) and distant metastasis (P = 0.012) inversely correlated with the overall survival time in NPC patients. Multivariate analysis showed that CENP-F expression was an independent prognostic indicator for the survival of the patient. Moreover, we found that ZOL or FTI-277 could significantly enhance the chemotherapeutic sensitivity of NPC cell lines (HONE1 and 6-10B) with high CENP-F expression to cisplatin, although ZOL or FTI-277 alone only exhibited a minor inhibitory effect to NPC cells. Conclusion Our data suggest that CENP-F protein is a valuable marker of NPC progression, and CENP-F expression is associated with poor overall survival of patients. In addition, our data indicate a potential benefit of combining ZOL or FTI-277 with cisplatin in NPC suggesting that CENP-F expression may have therapeutic implications.
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102
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Wordeman L. How kinesin motor proteins drive mitotic spindle function: Lessons from molecular assays. Semin Cell Dev Biol 2010; 21:260-8. [PMID: 20109570 PMCID: PMC2844474 DOI: 10.1016/j.semcdb.2010.01.018] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 01/19/2010] [Indexed: 12/31/2022]
Abstract
Kinesins are enzymes that use the energy of ATP to perform mechanical work. There are approximately 14 families of kinesins within the kinesin superfamily. Family classification is derived primarily from alignments of the sequences of the core motor domain. For this reason, the enzymatic behavior and motility of each motor generally reflects its family. At the cellular level, kinesin motors perform a variety of functions during cell division and within the mitotic spindle to ensure that chromosomes are segregated with the highest fidelity possible. The cellular functions of these motors are intimately related to their mechanical and enzymatic properties at the single molecule level. For this reason, motility studies designed to evaluate the activity of purified molecular motors are a requirement in order to understand, mechanistically, how these motors make the mitotic spindle work and what can cause the spindle to fail. This review will focus on a selection of illustrative kinesins, which have been studied at the molecular level in order to inform our understanding of their function in cells. In addition, the review will endeavor to point out some kinesins that have been studied extensively but which still lack sufficient molecular underpinnings to fully predict their contribution to spindle function.
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Affiliation(s)
- Linda Wordeman
- Department of Physiology & Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, United States.
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103
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Qian X, McDonald A, Zhou HJ, Adams ND, Parrish CA, Duffy KJ, Fitch DM, Tedesco R, Ashcraft LW, Yao B, Jiang H, Huang JK, Marin MV, Aroyan CE, Wang J, Ahmed S, Burgess JL, Chaudhari AM, Donatelli CA, Darcy MG, Ridgers LH, Newlander KA, Schmidt SJ, Chai D, Colón M, Zimmerman MN, Lad L, Sakowicz R, Schauer S, Belmont L, Baliga R, Pierce DW, Finer JT, Wang Z, Morgan BP, Morgans DJ, Auger KR, Sung CM, Carson JD, Luo L, Hugger ED, Copeland RA, Sutton D, Elliott JD, Jackson JR, Wood KW, Dhanak D, Bergnes G, Knight SD. Discovery of the First Potent and Selective Inhibitor of Centromere-Associated Protein E: GSK923295. ACS Med Chem Lett 2010; 1:30-4. [PMID: 24900171 DOI: 10.1021/ml900018m] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 01/04/2010] [Indexed: 11/29/2022] Open
Abstract
Inhibition of mitotic kinesins represents a novel approach for the discovery of a new generation of anti-mitotic cancer chemotherapeutics. We report here the discovery of the first potent and selective inhibitor of centromere-associated protein E (CENP-E) 3-chloro-N-{(1S)-2-[(N,N-dimethylglycyl)amino]-1-[(4-{8-[(1S)-1-hydroxyethyl]imidazo[1,2-a]pyridin-2-yl}phenyl)methyl]ethyl}-4-[(1-methylethyl)oxy]benzamide (GSK923295; 1), starting from a high-throughput screening hit, 3-chloro-4-isopropoxybenzoic acid 2. Compound 1 has demonstrated broad antitumor activity in vivo and is currently in human clinical trials.
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Affiliation(s)
- Xiangping Qian
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Andrew McDonald
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Han-Jie Zhou
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Nicholas D. Adams
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Cynthia A. Parrish
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Kevin J. Duffy
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Duke M. Fitch
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Rosanna Tedesco
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Luke W. Ashcraft
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Bing Yao
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Hong Jiang
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Jennifer K. Huang
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Melchor V. Marin
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Carrie E. Aroyan
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Jianchao Wang
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Seyed Ahmed
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Joelle L. Burgess
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Amita M. Chaudhari
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Carla A. Donatelli
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Michael G. Darcy
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Lance H. Ridgers
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Ken A. Newlander
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Stanley J. Schmidt
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Deping Chai
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Mariela Colón
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Michael N. Zimmerman
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Latesh Lad
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Roman Sakowicz
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Stephen Schauer
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Lisa Belmont
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Ramesh Baliga
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Daniel W. Pierce
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Jeffrey T. Finer
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Zhengping Wang
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Bradley P. Morgan
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - David J. Morgans
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Kurt R. Auger
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Chiu-Mei Sung
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Jeff D. Carson
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Lusong Luo
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Erin D. Hugger
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Robert A. Copeland
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - David Sutton
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - John D. Elliott
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Jeffrey R. Jackson
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Kenneth W. Wood
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Dashyant Dhanak
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Gustave Bergnes
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
| | - Steven D. Knight
- Cytokinetics, Inc., 280 E Grand Avenue, South San Francisco, California 94080
- Oncology R&D, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426
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104
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Maia AF, Feijão T, Vromans MJM, Sunkel CE, Lens SMA. Aurora B kinase cooperates with CENP-E to promote timely anaphase onset. Chromosoma 2010; 119:405-13. [PMID: 20354862 DOI: 10.1007/s00412-010-0265-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 02/04/2010] [Accepted: 02/14/2010] [Indexed: 01/06/2023]
Abstract
Error-free chromosome segregation requires that all chromosomes biorient on the mitotic spindle. The motor protein Centromere-associated protein E (CENP-E) facilitates chromosome congression by mediating the lateral sliding of sister chromatids along existing K-fibers, while the mitotic kinase Aurora B detaches kinetochore-microtubule interactions that are not bioriented. Whether these activities cooperate to promote efficient chromosome biorientation and timely anaphase onset is not known. We here show that the chromosomes that fail to congress after CENP-E depletion displayed high centromeric Aurora B kinase activity. This activity destabilized spindle pole proximal kinetochore-microtubule interactions resulting in a checkpoint-dependent mitotic delay that allowed CENP-E-independent chromosome congression, thus reducing chromosome segregation errors. This shows that Aurora B keeps the mitotic checkpoint active by destabilizing kinetochore fibers of polar chromosomes to permit chromosome congression in CENP-E-compromised cells and implies that this kinase normally prevents pole proximal syntelic attachments to allow CENP-E-mediated congression of mono-oriented chromosomes.
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Affiliation(s)
- André F Maia
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
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105
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Platani M, Santarella-Mellwig R, Posch M, Walczak R, Swedlow JR, Mattaj IW. The Nup107-160 nucleoporin complex promotes mitotic events via control of the localization state of the chromosome passenger complex. Mol Biol Cell 2010; 20:5260-75. [PMID: 19864462 DOI: 10.1091/mbc.e09-05-0377] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The human Nup107-160 nucleoporin complex plays a major role in formation of the nuclear pore complex and is localized to kinetochores in mitosis. Here we report that Seh1, a component of the Nup107-160 complex, functions in chromosome alignment and segregation by regulating the centromeric localization of Aurora B and other chromosome passenger complex proteins. Localization of CENP-E is not affected by Seh1 depletion and analysis by electron microscopy showed that microtubule kinetochore attachments are intact. Seh1-depleted cells show impaired Aurora B localization, which results in severe defects in biorientation and organization of the spindle midzone and midbody. Our results indicate that a major function of the Nup107 complex in mitosis is to ensure the proper localization of the CPC at the centromere.
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Affiliation(s)
- Melpomeni Platani
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH93JR, United Kingdom.
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106
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Savoian MS, Glover DM. Drosophila Klp67A binds prophase kinetochores to subsequently regulate congression and spindle length. J Cell Sci 2010; 123:767-76. [DOI: 10.1242/jcs.055905] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The kinesin-8 proteins are a family of microtubule-depolymerising motor molecules, which, despite their highly conserved roles in chromosome alignment and spindle dynamics, remain poorly characterised. Here, we report that the Drosophila kinesin-8 protein, Klp67A, exists in two spatially and functionally separable metaphase pools: at kinetochores and along the spindle. Fixed and live-cell analyses of different Klp67A recombinant variants indicate that this kinesin-8 first collects at kinetochores during prophase and, by metaphase, localises to the kinetochore outerplate. Although the catalytic motor activity of Klp67A is required for efficient kinetochore recruitment at all times, microtubules are entirely dispensable for this process. The tail of Klp67A does not play a role in kinetochore accumulation, but is both necessary and sufficient for spindle association. Using functional assays, we reveal that chromosome position and spindle length are determined by the microtubule-depolymerising motor activity of Klp67A exclusively when located at kinetochores, but not along the spindle. These data reveal that, unlike other metazoan kinesin-8 proteins, Klp67A binds the nascent prophase and mature metaphase kinetochore. From this location, Klp67A uses its motor activity to ensure chromosome alignment and proper spindle length.
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Affiliation(s)
| | - David M. Glover
- University of Cambridge, Department of Genetics, Cambridge, CB2 3EH, UK
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107
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Johnson MK, Wise DA. Distribution of kinetochore fragments during mitosis with unreplicated genomes. Cytoskeleton (Hoboken) 2010; 67:172-7. [PMID: 20175217 DOI: 10.1002/cm.20434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
When hydroxyurea and caffeine are added to Chinese hamster ovary cells, the cells bypass the S-phase checkpoint, and enter unscheduled mitosis. These cells build a morphologically normal spindle, and distribute unreplicated kinetochore fragments to daughters. We examined these cells and found that they undergo a full repertoire of mitotic stages, with the exception of anaphase B. Spindle elongation did not occur in these cells. When taxol was added, treated cells arrested indicating that microtubule turnover was necessary for kinetochore fragment separation. When released from taxol arrest, these cells divided. Finally, we determined that mitosis with unreplicated genome cells separated kinetochore fragments relatively equally. This mitosis is minimal, but still successful in kinetochore separation, which provides insight into the mechanism of anaphase movement.
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Affiliation(s)
- Mary Kathrine Johnson
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA
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108
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Antitumor activity of an allosteric inhibitor of centromere-associated protein-E. Proc Natl Acad Sci U S A 2010; 107:5839-44. [PMID: 20167803 DOI: 10.1073/pnas.0915068107] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Centromere-associated protein-E (CENP-E) is a kinetochore-associated mitotic kinesin that is thought to function as the key receptor responsible for mitotic checkpoint signal transduction after interaction with spindle microtubules. We have identified GSK923295, an allosteric inhibitor of CENP-E kinesin motor ATPase activity, and mapped the inhibitor binding site to a region similar to that bound by loop-5 inhibitors of the kinesin KSP/Eg5. Unlike these KSP inhibitors, which block release of ADP and destabilize motor-microtubule interaction, GSK923295 inhibited release of inorganic phosphate and stabilized CENP-E motor domain interaction with microtubules. Inhibition of CENP-E motor activity in cultured cells and tumor xenografts caused failure of metaphase chromosome alignment and induced mitotic arrest, indicating that tight binding of CENP-E to microtubules is insufficient to satisfy the mitotic checkpoint. Consistent with genetic studies in mice suggesting that decreased CENP-E function can have a tumor-suppressive effect, inhibition of CENP-E induced tumor cell apoptosis and tumor regression.
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109
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Abstract
For over a century, scientists have strived to understand the mechanisms that govern the accurate segregation of chromosomes during mitosis. The most intriguing feature of this process, which is particularly prominent in higher eukaryotes, is the complex behaviour exhibited by the chromosomes. This behaviour is based on specific and highly regulated interactions between the chromosomes and spindle microtubules. Recent discoveries, enabled by high-resolution imaging combined with the various genetic, molecular, cell biological and chemical tools, support the idea that establishing and controlling the dynamic interaction between chromosomes and microtubules is a major factor in genomic fidelity.
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110
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Abstract
The faithful replication of DNA and the accurate segregation of genomic material from one generation to the next is critical in the maintenance of genomic stability. This chapter will describe the structure and assembly of an epigenetically inherited locus, the centromere, and its role in the processes by which sister chromatids are evenly segregated to daughter cells. During the G2 phase of the cell cycle kinetochores are assembled upon the chromatids. During mitosis, kinetochores attach chromosome(s) to the mitotic spindle. The kinetochore structure serves as the interface between the mitotic spindle and the chromatids and it is at the kinetochore where the forces that drive chromatid separation are generated. Unattached chromosomes fail to satisfy the spindle assembly checkpoint (SAC), resulting in cell cycle arrest. The centromere is the locus upon which the kinetochore assembles, and centromeres themselves are determined by their unique protein composition. Apart from budding yeast, centromeres are not specified simply by DNA sequence, but rather through chromatin composition and architecture and are thus epigenetically determined. Centromeres are built on a specific nucleosome not found elsewhere in the genome, in which histone H3 is replaced with a homologue - CENP-A or CenH3. This domain is flanked by heterochromatin and is folded to provide a 3-dimensional cylinder-like structure at metaphase that establishes the kinetochore on the surface of the mitotic chromosomes. A large family of CENtromere Proteins (CENPs) associates with centromeric chromatin throughout the cell cycle and are required for kinetochore function. Unlike the bulk of histones, CENP-A is not assembled concurrently with DNA synthesis in S-phase but rather assembles into the centromere in the subsequent G1 phase. The assembly of CENP-A chromatin following DNA replication and the re-establishment of this network of constitutive proteins have emerged as critical mechanisms for understanding how the centromere is replicated during the cell cycle.
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111
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Liu Z, Ling K, Wu X, Cao J, Liu B, Li S, Si Q, Cai Y, Yan C, Zhang Y, Weng Y. Reduced expression of cenp-e in human hepatocellular carcinoma. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2009; 28:156. [PMID: 20021663 PMCID: PMC2804602 DOI: 10.1186/1756-9966-28-156] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Accepted: 12/18/2009] [Indexed: 02/06/2023]
Abstract
Background CENP-E, one of spindle checkpoint proteins, plays a crucial role in the function of spindle checkpoint. Once CENP-E expression was interrupted, the chromosomes can not separate procedurally, and may result in aneuploidy which is a hallmark of most solid cancers, such as hepatocellular carcinoma (HCC). We investigate the expression of CENP-E in human hepatocellular carcinoma,. and analyze the effect of low CENP-E expression on chromosome separation in normal liver cell line (LO2). Methods We determined its levels in HCC and para-cancerous tissues, human hepatocellular carcinoma-derived cell line (HepG2) and LO2 cell line using real time quantitative PCR (QPCR) and Western blot. Further to know whether reduction in CENP-E expression impairs chromosomes separation in LO2 cells. we knocked down CENP-E using shRNA expressing vector and then count the aneuploid in LO2 cells using chromosomal counts assay. Results We found that both CENP-E mRNA and protein levels were significantly reduced in HCC tissues and HepG2 cells compared with para-cancerous tissues and LO2 cells, respectively. A significantly-increased proportion of aneuploid in these down-knocked LO2 cells compared with those treated with control shRNA vector. Conclusions Together with other results, these results reveal that CENP-E expression was reduced in human HCC tissue, and low CENP-E expression result in aneuploidy in LO2 cells.
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Affiliation(s)
- Zijie Liu
- The key laboratory of laboratory medical diagnostics, ministry of education; the faculty of laboratory medicine, Chongqing Medical University, Chongqing PR China.
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112
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Rosenfeld SS, van Duffelen M, Behnke-Parks WM, Beadle C, Corrreia J, Xing J. The ATPase cycle of the mitotic motor CENP-E. J Biol Chem 2009; 284:32858-68. [PMID: 19759394 DOI: 10.1074/jbc.m109.041210] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that the mitotic motor centrosome protein E (CENP-E) is capable of walking for more than 250 steps on its microtubule track without dissociating. We have examined the kinetics of this molecular motor to see if its enzymology explains this remarkable degree of processivity. We find that like the highly processive transport motor kinesin 1, the enzymatic cycle of CENP-E is characterized by rapid ATP binding, multiple enzymatic turnovers per diffusive encounter, and gating of nucleotide binding. These features endow CENP-E with a high duty cycle, a prerequisite for processivity. However, unlike kinesin 1, neck linker docking in CENP-E is slow, occurring at a rate closer to that for Eg5, a mitotic kinesin that takes only 5-10 steps per processive run. These results suggest that like kinesin 1, features outside of the catalytic domain of CENP-E may also play a role in regulating the processive behavior of this motor.
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Affiliation(s)
- Steven S Rosenfeld
- Department of Biology, Columbia University, New York, New York 10032, USA.
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113
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Maffini S, Maia ARR, Manning AL, Maliga Z, Pereira AL, Junqueira M, Shevchenko A, Hyman A, Yates JR, Galjart N, Compton DA, Maiato H. Motor-independent targeting of CLASPs to kinetochores by CENP-E promotes microtubule turnover and poleward flux. Curr Biol 2009; 19:1566-72. [PMID: 19733075 DOI: 10.1016/j.cub.2009.07.059] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 07/09/2009] [Accepted: 07/22/2009] [Indexed: 12/27/2022]
Abstract
Efficient chromosome segregation during mitosis relies on the coordinated activity of molecular motors with proteins that regulate kinetochore attachments to dynamic spindle microtubules [1]. CLASPs are conserved kinetochore- and microtubule-associated proteins encoded by two paralog genes, clasp1 and clasp2, and have been previously implicated in the regulation of kinetochore microtubule dynamics [2-4]. However, it remains unknown how CLASPs work in concert with other proteins to form a functional kinetochore microtubule interface. Here we have identified mitotic interactors of human CLASP1 via a proteomic approach. Among these, the microtubule plus-end-directed motor CENP-E [5] was found to form a complex with CLASP1 that colocalizes to multiple structures of the mitotic apparatus in human cells. We found that CENP-E recruits both CLASP1 and CLASP2 to kinetochores independently of its motor activity or the presence of microtubules. Depletion of CLASPs or CENP-E by RNA interference in human cells causes a significant and comparable reduction of kinetochore microtubule poleward flux and turnover rates and rescues spindle bipolarity in Kif2a-depleted cells. We conclude that CENP-E integrates two critical functions that are important for accurate chromosome movement and spindle architecture: one relying directly on its motor activity, and the other involving the targeting of key microtubule regulators to kinetochores.
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Affiliation(s)
- Stefano Maffini
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
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114
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Abstract
The process of mitosis is a validated point of intervention in cancer therapy and a variety of anti-mitotic drugs are successfully being used in the clinic. To date, all approved antimitotics target the spindle microtubules, thus interfering with spindle dynamics, leading to mitotic arrest and apoptosis. While effective, these drugs are also associated with a variety of side effects, including neurotoxicity. In recent years, mitotic kinesins have attracted significant attention in the search for novel, alternative mitotic drug targets. Due to their specific function in mitosis, targeting these proteins creates an opportunity for the development of more selective antimitotics with an improved side effect profile. In addition, kinesin inhibitors may overcome resistance to microtubule targeting drugs. Drug discovery efforts in this area have initially focused on the plus-end directed kinesin spindle protein (KSP) and a variety of compounds are currently undergoing clinical testing.
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115
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Kong X, Ball AR, Sonoda E, Feng J, Takeda S, Fukagawa T, Yen TJ, Yokomori K. Cohesin associates with spindle poles in a mitosis-specific manner and functions in spindle assembly in vertebrate cells. Mol Biol Cell 2009; 20:1289-301. [PMID: 19116315 PMCID: PMC2649254 DOI: 10.1091/mbc.e08-04-0419] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 12/11/2008] [Accepted: 12/19/2008] [Indexed: 12/16/2022] Open
Abstract
Cohesin is an essential protein complex required for sister chromatid cohesion. Cohesin associates with chromosomes and establishes sister chromatid cohesion during interphase. During metaphase, a small amount of cohesin remains at the chromosome-pairing domain, mainly at the centromeres, whereas the majority of cohesin resides in the cytoplasm, where its functions remain unclear. We describe the mitosis-specific recruitment of cohesin to the spindle poles through its association with centrosomes and interaction with nuclear mitotic apparatus protein (NuMA). Overexpression of NuMA enhances cohesin accumulation at spindle poles. Although transient cohesin depletion does not lead to visible impairment of normal spindle formation, recovery from nocodazole-induced spindle disruption was significantly impaired. Importantly, selective blocking of cohesin localization to centromeres, which disrupts centromeric sister chromatid cohesion, had no effect on this spindle reassembly process, clearly separating the roles of cohesin at kinetochores and spindle poles. In vitro, chromosome-independent spindle assembly using mitotic extracts was compromised by cohesin depletion, and it was rescued by addition of cohesin that was isolated from mitotic, but not S phase, cells. The combined results identify a novel spindle-associated role for human cohesin during mitosis, in addition to its function at the centromere/kinetochore regions.
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Affiliation(s)
- Xiangduo Kong
- *Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700
| | - Alexander R. Ball
- *Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700
| | - Eiichiro Sonoda
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Jie Feng
- Fox Chase Cancer Center, Philadelphia, PA 19111; and
| | - Shunichi Takeda
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Tatsuo Fukagawa
- Department of Molecular Genetics, National Institute of Genetics and SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Tim J. Yen
- Fox Chase Cancer Center, Philadelphia, PA 19111; and
| | - Kyoko Yokomori
- *Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700
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116
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Henderson MC, Shaw YJY, Wang H, Han H, Hurley LH, Flynn G, Dorr RT, Von Hoff DD. UA62784, a novel inhibitor of centromere protein E kinesin-like protein. Mol Cancer Ther 2009; 8:36-44. [PMID: 19139111 DOI: 10.1158/1535-7163.mct-08-0789] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pancreatic carcinoma is the fourth leading cause of death from cancer. Novel targets and therapeutic options are needed to aid in the treatment of pancreatic cancer. The compound UA62784 is a novel fluorenone with inhibitory activity against the centromere protein E (CENP-E) kinesin-like protein. UA62784 was isolated due to its selectivity in isogenic pancreatic carcinoma cell lines with a deletion of the DPC4 gene. UA62784 causes mitotic arrest by inhibiting chromosome congression at the metaphase plate likely through inhibition of the microtubule-associated ATPase activity of CENP-E. Furthermore, CENP-E binding to kinetochores during mitosis is not affected by UA62784, suggesting that the target lies within the motor domain of CENP-E. UA62784 is a novel specific inhibitor of CENP-E and its activity suggests a potential role for antimitotic drugs in treating pancreatic carcinomas.
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Affiliation(s)
- Meredith C Henderson
- Arizona Cancer Center, BIO5 Institute, College of Pharmacy, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724-5024, USA
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117
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Wood KW, Chua P, Sutton D, Jackson JR. Centromere-associated protein E: a motor that puts the brakes on the mitotic checkpoint. Clin Cancer Res 2009; 14:7588-92. [PMID: 19047083 DOI: 10.1158/1078-0432.ccr-07-4443] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cell cycle checkpoints have long been recognized as important nodes for regulating cell proliferation and maintaining genomic integrity. These checkpoints are often altered in cancer and represent promising points for therapeutic intervention. Until recently, direct targeting of the mitotic checkpoint has been an untapped area for cancer drug discovery. Regulation of the mitotic checkpoint is complex, but many of the critical players have been identified and functionally characterized. A substantial number of these proteins can be localized to the kinetochore, a structure located at the centromeric region of each mitotic chromosome. The kinetochore mediates chromosome attachment to spindle microtubules and subsequent chromosome movement. The mitotic checkpoint monitors microtubule attachment and chromosome position on the mitotic spindle, inhibiting progression into anaphase until proper attachment and metaphase positioning is achieved. Centromere-associated protein E is a kinesin microtubule motor protein that plays an essential role in integrating the mechanics of microtubule-chromosome interactions with mitotic checkpoint signaling, and has emerged as a novel target for cancer therapy.
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118
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Huang H, Hittle J, Zappacosta F, Annan RS, Hershko A, Yen TJ. Phosphorylation sites in BubR1 that regulate kinetochore attachment, tension, and mitotic exit. ACTA ACUST UNITED AC 2008; 183:667-80. [PMID: 19015317 PMCID: PMC2582891 DOI: 10.1083/jcb.200805163] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BubR1 kinase is essential for the mitotic checkpoint and also for kinetochores to establish microtubule attachments. In this study, we report that BubR1 is phosphorylated in mitosis on four residues that differ from sites recently reported to be phosphorylated by Plk1 (Elowe, S., S. Hummer, A. Uldschmid, X. Li, and E.A. Nigg. 2007. Genes Dev. 21:2205–2219; Matsumura, S., F. Toyoshima, and E. Nishida. 2007. J. Biol. Chem. 282:15217–15227). S670, the most conserved residue, is phosphorylated at kinetochores at the onset of mitosis and dephosphorylated before anaphase onset. Unlike the Plk1-dependent S676 phosphorylation, S670 phosphorylation is sensitive to microtubule attachments but not to kinetochore tension. Functionally, phosphorylation of S670 is essential for error correction and for kinetochores with end-on attachments to establish tension. Furthermore, in vitro data suggest that the phosphorylation status of BubR1 is important for checkpoint inhibition of the anaphase-promoting complex/cyclosome. Finally, RNA interference experiments show that Mps1 is a major but not the exclusive kinase that specifies BubR1 phosphorylation in vivo. The combined data suggest that BubR1 may be an effector of multiple kinases that are involved in discrete aspects of kinetochore attachments and checkpoint regulation.
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Affiliation(s)
- Haomin Huang
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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119
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Farnesyltransferase inhibitors target multiple endothelial cell functions in angiogenesis. Angiogenesis 2008; 11:337-46. [DOI: 10.1007/s10456-008-9115-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 08/07/2008] [Indexed: 12/15/2022]
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120
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Phosphorylation relieves autoinhibition of the kinetochore motor Cenp-E. Mol Cell 2008; 29:637-43. [PMID: 18342609 DOI: 10.1016/j.molcel.2008.01.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 11/16/2007] [Accepted: 01/08/2008] [Indexed: 12/19/2022]
Abstract
During mitosis, chromosome alignment depends on the regulated dynamics of microtubules and on motor protein activities. At the kinetochore, the interplay between microtubule-binding proteins, motors, and kinases is poorly understood. Cenp-E is a kinetochore-associated kinesin involved in chromosome congression, but the mechanism by which this is achieved is unclear. Here, we present a study of the regulation of Cenp-E motility by using purified full-length (FL) Xenopus Cenp-E protein, which demonstrates that FL Cenp-E is a genuine plus-end-directed motor. Furthermore, we find that the Cenp-E tail completely blocks the motility of Cenp-E in vitro. This is achieved through direct interaction between its motor and tail domains. Finally, we show that Cenp-E autoinhibition is reversed by MPS1- or CDK1-cyclin B-mediated phosphorylation of the Cenp-E tail. This suggests a model of dynamic control of Cenp-E motility, and hence chromosome congression, dependent upon phosphorylation at the kinetochore.
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121
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Kim Y, Heuser JE, Waterman CM, Cleveland DW. CENP-E combines a slow, processive motor and a flexible coiled coil to produce an essential motile kinetochore tether. ACTA ACUST UNITED AC 2008; 181:411-9. [PMID: 18443223 PMCID: PMC2364708 DOI: 10.1083/jcb.200802189] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The mitotic kinesin centromere protein E (CENP-E) is an essential kinetochore component that directly contributes to the capture and stabilization of spindle microtubules by kinetochores. Although reduction in CENP-E leads to high rates of whole chromosome missegregation, neither its properties as a microtubule-dependent motor nor how it contributes to the dynamic linkage between kinetochores and microtubules is known. Using single-molecule assays, we demonstrate that CENP-E is a very slow, highly processive motor that maintains microtubule attachment for long periods. Direct visualization of full-length Xenopus laevis CENP-E reveals a highly flexible 230-nm coiled coil separating its kinetochore-binding and motor domains. We also show that full-length CENP-E is a slow plus end–directed motor whose activity is essential for metaphase chromosome alignment. We propose that the highly processive microtubule-dependent motor activity of CENP-E serves to power chromosome congression and provides a flexible, motile tether linking kinetochores to dynamic spindle microtubules.
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Affiliation(s)
- Yumi Kim
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA
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122
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SUMO-2/3 modification and binding regulate the association of CENP-E with kinetochores and progression through mitosis. Mol Cell 2008; 29:729-41. [PMID: 18374647 DOI: 10.1016/j.molcel.2008.01.013] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 11/15/2007] [Accepted: 01/07/2008] [Indexed: 12/31/2022]
Abstract
SUMOylation is essential for cell-cycle regulation in invertebrates; however, its functions during the mammalian cell cycle are largely uncharacterized. Mammals express three SUMO paralogs: SUMO-1, SUMO-2, and SUMO-3 (SUMO-2 and SUMO-3 are 96% identical and referred to as SUMO-2/3). We found that SUMO-2/3 localize to centromeres and condensed chromosomes, whereas SUMO-1 localizes to the mitotic spindle and spindle midzone, indicating that SUMO paralogs regulate distinct mitotic processes in mammalian cells. Consistent with this, global inhibition of SUMOylation caused a prometaphase arrest due to defects in targeting the microtubule motor protein CENP-E to kinetochores. CENP-E was found to be modified specifically by SUMO-2/3 and to possess SUMO-2/3 polymeric chain-binding activity essential for kinetochore localization. Our findings indicate that SUMOylation is a key regulator of the mammalian cell cycle, with SUMO-1 and SUMO-2/3 modification of different proteins regulating distinct processes.
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123
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Suijkerbuijk SJE, Kops GJPL. Preventing aneuploidy: the contribution of mitotic checkpoint proteins. Biochim Biophys Acta Rev Cancer 2008; 1786:24-31. [PMID: 18472014 DOI: 10.1016/j.bbcan.2008.04.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 02/18/2008] [Accepted: 04/08/2008] [Indexed: 12/21/2022]
Abstract
Aneuploidy, an abnormal number of chromosomes, is a trait shared by most solid tumors. Chromosomal instability (CIN) manifested as aneuploidy might promote tumorigenesis and cause increased resistance to anti-cancer therapies. The mitotic checkpoint or spindle assembly checkpoint is a major signaling pathway involved in the prevention of CIN. We review current knowledge on the contribution of misregulation of mitotic checkpoint proteins to tumor formation and will address to what extent this contribution is due to chromosome segregation errors directly. We propose that both checkpoint and non-checkpoint functions of these proteins contribute to the wide array of oncogenic phenotypes seen upon their misregulation.
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Affiliation(s)
- Saskia J E Suijkerbuijk
- Department of Physiological Chemistry, UMC Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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124
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Abstract
In vivo studies suggest that centromeric protein E (CENP-E), a kinesin-7 family member, plays a key role in the movement of chromosomes toward the metaphase plate during mitosis. How CENP-E accomplishes this crucial task, however, is not clear. Here we present single-molecule measurements of CENP-E that demonstrate that this motor moves processively toward the plus end of microtubules, with an average run length of 2.6 +/- 0.2 mum, in a hand-over-hand fashion, taking 8-nm steps with a stall force of 6 +/- 0.1 pN. The ATP dependence of motor velocity obeys Michaelis-Menten kinetics with K(M,ATP) = 35 +/- 5 muM. All of these features are remarkably similar to those for kinesin-1-a highly processive transport motor. We, therefore, propose that CENP-E transports chromosomes in a manner analogous to how kinesin-1 transports cytoplasmic vesicles.
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125
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Gerald NJ, Coppens I, Dwyer DM. Molecular characterization and expression of a novel kinesin which localizes with the kinetoplast in the human pathogen,Leishmania donovani. ACTA ACUST UNITED AC 2008; 65:269-80. [DOI: 10.1002/cm.20259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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126
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Dalton WB, Nandan MO, Moore RT, Yang VW. Human cancer cells commonly acquire DNA damage during mitotic arrest. Cancer Res 2008; 67:11487-92. [PMID: 18089775 DOI: 10.1158/0008-5472.can-07-5162] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The mitotic checkpoint is a mechanism that arrests the progression to anaphase until all chromosomes have achieved proper attachment to mitotic spindles. In cancer cells, satisfaction of this checkpoint is frequently delayed or prevented by various defects, some of which have been causally implicated in tumorigenesis. At the same time, deliberate induction of mitotic arrest has proved clinically useful, as antimitotic drugs that interfere with proper chromosome-spindle interactions are effective anticancer agents. However, how mitotic arrest contributes to tumorigenesis or antimitotic drug toxicity is not well defined. Here, we report that mitotic chromosomes can acquire DNA breaks during both pharmacologic and genetic induction of mitotic arrest in human cancer cells. These breaks activate a DNA damage response, occur independently of cell death, and subsequently manifest as karyotype alterations. Such breaks can also occur spontaneously, particularly in cancer cells containing mitotic spindle abnormalities. Moreover, we observed evidence of some breakage in primary human cells. Our findings thus describe a novel source of DNA damage in human cells. They also suggest that mitotic arrest may promote tumorigenesis and antimitotic toxicity by provoking DNA damage.
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Affiliation(s)
- W Brian Dalton
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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127
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Cheeseman IM, Desai A. Molecular architecture of the kinetochore-microtubule interface. Nat Rev Mol Cell Biol 2008; 9:33-46. [PMID: 18097444 DOI: 10.1038/nrm2310] [Citation(s) in RCA: 688] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Segregation of the replicated genome during cell division in eukaryotes requires the kinetochore to link centromeric DNA to spindle microtubules. The kinetochore is composed of a number of conserved protein complexes that direct its specification and assembly, bind to spindle microtubules and regulate chromosome segregation. Recent studies have identified more than 80 kinetochore components, and are revealing how these proteins are organized into the higher order kinetochore structure, as well as how they function to achieve proper chromosome segregation.
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Affiliation(s)
- Iain M Cheeseman
- Whitehead Institute for Biomedical Research, and Department of Biology, Massachusetts Institute of Technology, Nine Cambridge Center, Cambridge, Massachusetts 02142, USA.
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128
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Walczak CE, Heald R. Mechanisms of mitotic spindle assembly and function. INTERNATIONAL REVIEW OF CYTOLOGY 2008; 265:111-58. [PMID: 18275887 DOI: 10.1016/s0074-7696(07)65003-7] [Citation(s) in RCA: 280] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The mitotic spindle is the macromolecular machine that segregates chromosomes to two daughter cells during mitosis. The major structural elements of the spindle are microtubule polymers, whose intrinsic polarity and dynamic properties are critical for bipolar spindle organization and function. In most cell types, spindle microtubule nucleation occurs primarily at two centrosomes, which define the spindle poles, but microtubules can also be generated by the chromosomes and within the spindle itself. Many associated factors help organize the spindle, including molecular motors and regulators of microtubule dynamics. The past decade has provided a wealth of information on the molecular players that are critical for spindle assembly as well as a high-resolution view of the intricate movements and dynamics of the spindle microtubules and the chromosomes. In this chapter we provide a historical account of the key observations leading to current models of spindle assembly, as well as an up-to-date status report on this exciting field.
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Affiliation(s)
- Claire E Walczak
- Medical Sciences Program, Indiana University, Bloomington, Indiana 47405, USA
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129
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Liu L, Keefe DL. Defective cohesin is associated with age-dependent misaligned chromosomes in oocytes. Reprod Biomed Online 2008; 16:103-12. [PMID: 18252055 DOI: 10.1016/s1472-6483(10)60562-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aneuploidy often results from chromosome misalignment at metaphases. Oocytes from senescence-accelerated mice (SAM) exhibit increased chromosome misalignment with age, which originates from nuclear factors. This work sought to further characterize the underlying defects of chromosome misalignments. Using immunofluorescence microscopy with specific antibodies, several specific components associated with spindles or chromosomes, including centrosomes, centromeres and cohesin complex were examined. No obvious differences were found in the distribution of centrosome focus at the spindle pole of oocytes from young and aged SAM, regardless of chromosome alignments, although cytoplasmic centrosome foci were significantly reduced in aged SAM (P < 0.0001). Oocytes from both young and aged SAM exhibited centromere-associated protein-E (CENP-E) at centromeres of all chromosomes, including misaligned chromosomes from aged SAM, demonstrating that CENP-E did not contribute to chromosome misalignments. Notably, both meiotic cohesin proteins located between sister chromatids, REC8 (recombinant 8), STAG3 (stromal antigen 3) and SMC1beta, were remarkably reduced in oocytes from aged SAM. Further, degradation of the cohesin was even more obvious in SAM than in hybrid F1 mice with age, which may explain why SAM are vulnerable to aneuploidy. This natural ageing mouse model shows that defective cohesin coincides with increased incidence of chromosome misalignment and precocious separations of sister chromatids.
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Affiliation(s)
- Lin Liu
- Department of Obstetrics and Gynecology, University of South Florida College of Medicine, Tampa, Florida 33612, USA.
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130
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Vogt E, Kirsch-Volders M, Parry J, Eichenlaub-Ritter U. Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error. Mutat Res 2007; 651:14-29. [PMID: 18096427 DOI: 10.1016/j.mrgentox.2007.10.015] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 10/28/2007] [Indexed: 01/21/2023]
Abstract
The spindle assembly checkpoint (SAC) monitors attachment to microtubules and tension on chromosomes in mitosis and meiosis. It represents a surveillance mechanism that halts cells in M-phase in the presence of unattached chromosomes, associated with accumulation of checkpoint components, in particular, Mad2, at the kinetochores. A complex between the anaphase promoting factor/cylosome (APC/C), its accessory protein Cdc20 and proteins of the SAC renders APC/C inactive, usually until all chromosomes are properly assembled at the spindle equator (chromosome congression) and under tension from spindle fibres. Upon release from the SAC the APC/C can target proteins like cyclin B and securin for degradation by the proteasome. Securin degradation causes activation of separase proteolytic enzyme, and in mitosis cleavage of cohesin proteins at the centromeres and arms of sister chromatids. In meiosis I only the cohesin proteins at the sister chromatid arms are cleaved. This requires meiosis specific components and tight regulation by kinase and phosphatase activities. There is no S-phase between meiotic divisions. Second meiosis resembles mitosis. Mammalian oocytes arrest constitutively at metaphase II in presence of aligned chromosomes, which is due to the activity of the cytostatic factor (CSF). The SAC has been identified in spermatogenesis and oogenesis, but gender-differences may contribute to sex-specific differential responses to aneugens. The age-related reduction in expression of components of the SAC in mammalian oocytes may act synergistically with spindle and other cell organelles' dysfunction, and a partial loss of cohesion between sister chromatids to predispose oocytes to errors in chromosome segregation. This might affect dose-response to aneugens. In view of the tendency to have children at advanced maternal ages it appears relevant to pursue studies on consequences of ageing on the susceptibility of human oocytes to the induction of meiotic error by aneugens and establish models to assess risks to human health by environmental exposures.
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Affiliation(s)
- E Vogt
- University of Bielefeld, Faculty of Biology, Gene Technology/Microbiology, Bielefeld, Germany
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131
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Liu J, Desai A, Onuchic JN, Hwa T. A mechanobiochemical mechanism for monooriented chromosome oscillation in mitosis. Proc Natl Acad Sci U S A 2007; 104:16104-9. [PMID: 17911248 PMCID: PMC2042169 DOI: 10.1073/pnas.0707689104] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Indexed: 11/18/2022] Open
Abstract
During mitosis, the condensed chromosomes undergo a series of spectacular oscillations after they are captured in an end-on manner by kinetochore microtubules (KMT) emanating from the spindle poles. Such oscillations are commonly attributed to tug-of-war-like mechanisms, where the mechanical force imbalance alone drives the chromosome movement. However, a large portion of the force imbalance upon the chromosome is absorbed by the kinetochore and may not drive chromosome movement directly. Mounting evidence suggests that such resistance by the kinetochores regulates the chemical reactions of KMT plus-end growth and shrinkage, which have been shown as the determinant of the chromosome antipoleward (AP) and poleward movements. Here we incorporate this important regulatory feature, propose a mechanobiochemical feedback mechanism, and apply it to the monooriented chromosome oscillation, the early stage of the series of observed chromosome oscillations. In this model, the mechanical movement of the chromosome and the local biochemical reactions at the attached kinetochore region form a feedback loop that drives the oscillation. The force imbalance exerted on the chromosomes provides a bias (via mechanically sensitive proteins) on the local biochemical reactions controlling the KMT plus-end dynamics, and the movement of the chromosome in turn changes the forces exerted on it through the experimentally supported gradient in AP force. The proposed feedback mechanism can generate oscillatory behavior that depends on the topology of the feedback loop but is largely independent of the detailed molecular mechanism. We suggest potential molecular players, whose perturbation may allow direct experimental tests of the model.
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Affiliation(s)
- Jian Liu
- Center for Theoretical Biological Physics and
| | - Arshad Desai
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093-0374
| | | | - Terence Hwa
- Center for Theoretical Biological Physics and
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132
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Abstract
Basic research that has focused on achieving a mechanistic understanding of mitosis has provided unprecedented molecular and biochemical insights into this highly complex phase of the cell cycle. The discovery process has uncovered an ever-expanding list of novel proteins that orchestrate and coordinate spindle formation and chromosome dynamics during mitosis. That many of these proteins appear to function solely in mitosis makes them ideal targets for the development of mitosis-specific cancer drugs. The clinical successes seen with anti-microtubule drugs such as taxanes and the vinca alkaloids have also encouraged the development of drugs that specifically target mitosis. Drugs that selectively inhibit mitotic kinesins involved in spindle and kinetochore functions, as well as kinases that regulate these activities, are currently in various stages of clinical trials. Our increased understanding of mitosis has also revealed that this process is targeted by inhibitors of farnesyl transferase, histone deacetylase, and Hsp90. Although these drugs were originally designed to block cell proliferation by inhibiting signaling pathways and altering gene expression, it is clear now that these drugs can also directly interfere with the mitotic process. The increased attention to mitosis as a chemotherapeutic target has also raised an important issue regarding the cellular determinants that specify drug sensitivity. One likely contribution is the mitotic checkpoint, a failsafe mechanism that delays mitotic exit so that cells whose chromosomes are not properly attached to the spindle have extra time to correct their errors. As the biochemical activity of the mitotic checkpoint is finite, cells cannot indefinitely sustain the delay, as in cases where cells are treated with anti-mitotic drugs. When the mitotic checkpoint activity is eventually lost, cells will exit mitosis and become aneuploid. While many of the aneuploid cells may die because of massive chromosome imbalance, survivors that continue to proliferate will no doubt be selected. This is clearly an undesirable outcome, thus efforts to obtain fundamental insights into why some cells that arrest in mitosis die without exiting mitosis will be exceedingly important in enhancing our understanding of the drug sensitivity of cancer cells.
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Affiliation(s)
- Valery Sudakin
- Department of Oncology Research, GlaxoSmithKline, Collegeville, Pennsylvania, USA
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133
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Liu D, Ding X, Du J, Cai X, Huang Y, Ward T, Shaw A, Yang Y, Hu R, Jin C, Yao X. Human NUF2 Interacts with Centromere-associated Protein E and Is Essential for a Stable Spindle Microtubule-Kinetochore Attachment. J Biol Chem 2007; 282:21415-24. [PMID: 17535814 DOI: 10.1074/jbc.m609026200] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chromosome segregation in mitosis is orchestrated by dynamic interaction between spindle microtubules and the kinetochore, a multiprotein complex assembled onto centromeric DNA of the chromosome. Here, we show that Homo sapiens (Hs) NUF2 is required for stable kinetochore localization of centromere-associated protein E (CENP-E) in HeLa cells. HsNUF2 specifies the kinetochore association of CENP-E by interacting with its C-terminal domain. The region of HsNUF2 binding to CENP-E was mapped to its C-terminal domain by glutathione S-transferase pulldown and yeast two-hybrid assays. Suppression of synthesis of HsNUF2 by small interfering RNA abrogated the localization of CENP-E to the kinetochore, demonstrating the requirement of HsNUF2 for CENP-E kinetochore localization. In addition, depletion of HsNUF2 caused aberrant chromosome segregation. These HsNUF2-suppressed cells displayed reduced tension at kinetochores of bi-orientated chromosomes. Double knockdown of CENP-E and HsNUF2 further abolished the tension at the kinetochores. Our results indicate that HsNUF2 and CENP-E are required for organization of stable microtubule-kinetochore attachment that is essential for faithful chromosome segregation in mitosis.
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Affiliation(s)
- Dan Liu
- Laboratory of Cellular Dynamics, University of Science and Technology of China and the National Laboratory for Physical Sciences, Hefei 230027, China
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134
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Schafer-Hales K, Iaconelli J, Snyder JP, Prussia A, Nettles JH, El-Naggar A, Khuri FR, Giannakakou P, Marcus AI. Farnesyl transferase inhibitors impair chromosomal maintenance in cell lines and human tumors by compromising CENP-E and CENP-F function. Mol Cancer Ther 2007; 6:1317-28. [PMID: 17431110 DOI: 10.1158/1535-7163.mct-06-0703] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Farnesyl transferase inhibitors (FTI) exhibit anticancer activity as a single agent in preclinical studies and show promise in combination with other therapeutics in clinical trials. Previous studies show that FTIs arrest cancer cells in mitosis; however, the mechanism by which this occurs is unclear. Here, we observed that treatment of various cancer cell lines with the FTI lonafarnib caused mitotic chromosomal alignment defects, leaving cells in a pseudometaphase state, whereby both aligned chromosomes and chromosomes juxtaposed to the spindle poles (termed "lagging chromosomes") were observed in the same cell. To determine how this occurs, we investigated the functionality of two farnesylated mitotic proteins, CENP-E and CENP-F, which mediate chromosomal capture and alignment. The data show that lonafarnib in proliferating cancer cells depletes CENP-E and CENP-F from metaphase but not prometaphase kinetochores. Loss of CENP-E and CENP-F metaphase localization triggered aberrant chromosomal maintenance, causing aligned chromosomes to be prematurely released from the spindle equator and become lagging chromosomes, resulting in a mitotic delay. Furthermore, lonafarnib treatment reduces sister kinetochore tension and activates the BubR1 spindle checkpoint, suggesting that farnesylation of CENP-E and CENP-F is critical for their functionality in maintaining kinetochore-microtubule interactions. Importantly, apparently similar chromosomal alignment defects were observed in head and neck tumors samples from a phase I trial with lonafarnib, providing support that lonafarnib disrupts chromosomal maintenance in human cancers. Lastly, to examine how farnesylation could regulate CENP-E in mediating kinetochore-microtubule attachments, we examined possible docking motifs of a farnesyl group on the outer surface of the microtubule. This analysis revealed three hydrophobic patches on the tubulin dimer for insertion of a farnesyl group, alluding to the possibility of an association between a farnesyl group and the microtubule.
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135
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Manning AL, Compton DA. Mechanisms of spindle-pole organization are influenced by kinetochore activity in mammalian cells. Curr Biol 2007; 17:260-5. [PMID: 17276919 DOI: 10.1016/j.cub.2006.11.071] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/24/2006] [Accepted: 11/24/2006] [Indexed: 11/19/2022]
Abstract
The spindle is a fusiform bipolar-microtubule array that is responsible for chromosome segregation during mitosis. Focused poles are an essential feature of spindles in vertebrate somatic cells, and pole focusing has been shown to occur through a centrosome-independent self-organization mechanism where microtubule motors cross-link and focus microtubule minus ends. Most of our understanding of this mechanism for pole focusing derives from studies performed in cell-free extracts devoid of centrosomes and kinetochores. Here, we examine how sustained force from kinetochores influences the mechanism of pole focusing in cultured cells. We show that the motor-driven self-organization activities associated with NuMA (i.e., cytoplasmic dynein) and HSET are not necessary for pole focusing if sustained force from kinetochores is inhibited in Nuf2- or Mis12-deficient cells. Instead, pole organization relies on TPX2 as it cross-links spindle microtubules to centrosome-associated mitotic asters. Thus, both motor-driven and static-cross-linking mechanisms contribute to spindle-pole organization, and kinetochore activity influences the mechanism of spindle-pole organization. The motor-driven self-organization of microtubule minus ends at spindle poles is needed to organize spindle poles in vertebrate somatic cells when kinetochores actively exert force on spindle microtubules.
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Affiliation(s)
- Amity L Manning
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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136
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Musacchio A, Salmon ED. The spindle-assembly checkpoint in space and time. Nat Rev Mol Cell Biol 2007; 8:379-93. [PMID: 17426725 DOI: 10.1038/nrm2163] [Citation(s) in RCA: 1656] [Impact Index Per Article: 97.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In eukaryotes, the spindle-assembly checkpoint (SAC) is a ubiquitous safety device that ensures the fidelity of chromosome segregation in mitosis. The SAC prevents chromosome mis-segregation and aneuploidy, and its dysfunction is implicated in tumorigenesis. Recent molecular analyses have begun to shed light on the complex interaction of the checkpoint proteins with kinetochores--structures that mediate the binding of spindle microtubules to chromosomes in mitosis. These studies are finally starting to reveal the mechanisms of checkpoint activation and silencing during mitotic progression.
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Affiliation(s)
- Andrea Musacchio
- Department of Experimental Oncology, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy.
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137
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Grishchuk EL, Spiridonov IS, McIntosh JR. Mitotic chromosome biorientation in fission yeast is enhanced by dynein and a minus-end-directed, kinesin-like protein. Mol Biol Cell 2007; 18:2216-25. [PMID: 17409356 PMCID: PMC1877089 DOI: 10.1091/mbc.e06-11-0987] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Chromosome biorientation, the attachment of sister kinetochores to sister spindle poles, is vitally important for accurate chromosome segregation. We have studied this process by following the congression of pole-proximal kinetochores and their subsequent anaphase segregation in fission yeast cells that carry deletions in any or all of this organism's minus end-directed, microtubule-dependent motors: two related kinesin 14s (Pkl1p and Klp2p) and dynein. None of these deletions abolished biorientation, but fewer chromosomes segregated normally without Pkl1p, and to a lesser degree without dynein, than in wild-type cells. In the absence of Pkl1p, which normally localizes to the spindle and its poles, the checkpoint that monitors chromosome biorientation was defective, leading to frequent precocious anaphase. Ultrastructural analysis of mutant mitotic spindles suggests that Pkl1p contributes to error-free biorientation by promoting normal spindle pole organization, whereas dynein helps to anchor a focused bundle of spindle microtubules at the pole.
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Affiliation(s)
- Ekaterina L Grishchuk
- Molecular, Cellular, and Developmental Biology Department, University of Colorado at Boulder, Boulder, CO 80309, USA.
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138
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Jackson JR, Patrick DR, Dar MM, Huang PS. Targeted anti-mitotic therapies: can we improve on tubulin agents? Nat Rev Cancer 2007; 7:107-17. [PMID: 17251917 DOI: 10.1038/nrc2049] [Citation(s) in RCA: 380] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The advent of molecularly targeted drug discovery has facilitated the identification of a new generation of anti-mitotic therapies that target proteins with specific functions in mitosis. The exquisite selectivity for mitosis and the distinct ways in which these new agents interfere with mitosis provides the potential to not only overcome certain limitations of current tubulin-targeted anti-mitotic drugs, but to expand the scope of clinical efficacy that those drugs have established. The development of these new anti-mitotic drugs as targeted therapies faces significant challenges; nevertheless, these potential therapies also serve as unique tools to dissect the molecular mechanisms of the mitotic-checkpoint response.
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Affiliation(s)
- Jeffrey R Jackson
- GlaxoSmithKline, Oncology Center of Excellence in Drug Discovery, Department of Biology, Collegeville, Pennsylvania, USA.
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139
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Dinu CZ, Chrisey DB, Diez S, Howard J. Cellular Motors for Molecular Manufacturing. Anat Rec (Hoboken) 2007; 290:1203-12. [PMID: 17847054 DOI: 10.1002/ar.20599] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cells are composed of macromolecular structures of various sizes that act individually or collectively to maintain their viability and perform their function within the organism. This review focuses on one structure, the microtubule, and one of the motor proteins that move along it, conventional kinesin (kinesin 1). Recent work on the cellular functions of kinesins, such as the organization of microtubules during cellular division and the movement of the organelles and vesicles, offers insights into how biological motors might prove useful for organizing structures in engineered environments.
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Affiliation(s)
- C Z Dinu
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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140
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Rundle NT, Nelson J, Flory MR, Joseph J, Th'ng J, Aebersold R, Dasso M, Andersen RJ, Roberge M. An ent-kaurene that inhibits mitotic chromosome movement and binds the kinetochore protein ran-binding protein 2. ACS Chem Biol 2006; 1:443-50. [PMID: 17168522 DOI: 10.1021/cb600196w] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Using a chemical genetics screen, we have identified ent-15-oxokaurenoic acid (EKA) as a chemical that causes prolonged mitotic arrest at a stage resembling prometaphase. EKA inhibits the association of the mitotic motor protein centromeric protein E with kinetochores and inhibits chromosome movement. Unlike most antimitotic agents, EKA does not inhibit the polymerization or depolymerization of tubulin. To identify EKA-interacting proteins, we used a cell-permeable biotinylated form that retains biological activity to isolate binding proteins from living cells. Mass spectrometric analysis identified six EKA-binding proteins, including Ran-binding protein 2, a kinetochore protein whose depletion by small interfering RNA causes a similar mitotic arrest phenotype.
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Affiliation(s)
- Natalie T Rundle
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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141
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Liu D, Zhang N, Du J, Cai X, Zhu M, Jin C, Dou Z, Feng C, Yang Y, Liu L, Takeyasu K, Xie W, Yao X. Interaction of Skp1 with CENP-E at the midbody is essential for cytokinesis. Biochem Biophys Res Commun 2006; 345:394-402. [PMID: 16682006 DOI: 10.1016/j.bbrc.2006.04.062] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Accepted: 04/12/2006] [Indexed: 11/17/2022]
Abstract
Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis. Our previous studies show that microtubule motor CENP-E represents a link between attachment of spindle microtubules and the mitotic checkpoint signaling cascade. However, the molecular function of CENP-E at the midbody had remained elusive. Here we show that CENP-E interacts with Skp1 at the midbody and participates in cytokinesis. CENP-E interacts with Skp1 in vitro and in vivo via its coiled-coil domain. Our yeast two-hybrid assays mapped the binding interfaces to the central stalk region of CENP-E (955-1571 aa) and the C-terminal 33 amino acids of Skp1, respectively. Our immunocytochemical studies revealed that CENP-E targets to the midbody prior to Skp1 and the midbody localization of CENP-E becomes diminished as Skp1 arrives at the midbody. Suppression of Skp1 in mitotic HeLa cells by siRNA resulted in accumulation of telophase cells with elongated inter-cell bridges and with midbodies stretched 2-3 times longer than that of normal cells. These Skp1-eliminated or -suppressed cells accumulate higher level of CENP-E, suggesting that spatiotemporal regulation of CENP-E degradation at the midbody is essential for cytokinesis. Over-expression of Skp1 lacking the CENP-E-binding domain confirmed that Skp1-CENP-E interaction is essential for faithful cytokinesis. We hypothesize that CENP-E degradation is essential for faithful mitotic exit and the proteolysis of CENP-E is mediated by SCF via a direct Skp1 link.
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Affiliation(s)
- Dan Liu
- Division of Cellular Dynamics, Hefei National Laboratory and University of Science & Technology of China, Hefei, China 230027
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142
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Hannak E, Heald R. Xorbit/CLASP links dynamic microtubules to chromosomes in the Xenopus meiotic spindle. ACTA ACUST UNITED AC 2006; 172:19-25. [PMID: 16390996 PMCID: PMC2063525 DOI: 10.1083/jcb.200508180] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
A family of microtubule (MT)-binding proteins, Orbit/multiple asters/cytoplasmic linker protein–associated protein, has emerged as an important player during mitosis, but their functional mechanisms are poorly understood. In this study, we used meiotic egg extracts to gain insight into the role of the Xenopus laevis homologue Xorbit in spindle assembly and function. Xorbit immunodepletion or its inhibition by a dominant-negative fragment resulted in chromosome alignment defects and aberrant MT structures, including monopolar and small spindles. Xorbit-depleted extracts failed to nucleate MTs around chromatin-coated beads, indicating its essential requirement for spindle assembly in the absence of centrosomes and kinetochores. Xorbit's MT stabilizing effect was most apparent during anaphase, when spindle MTs depolymerized rapidly upon Xorbit inhibition. Biochemical interaction between a COOH-terminal Xorbit fragment and the kinetochore-associated kinesin centromeric protein E may contribute to Xorbit's role in chromosome congression. We propose that Xorbit tethers dynamic MT plus ends to kinetochores and chromatin, providing a stabilizing activity that is crucial for spindle assembly and chromosome segregation.
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Affiliation(s)
- Eva Hannak
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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143
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Vanstraelen M, Inzé D, Geelen D. Mitosis-specific kinesins in Arabidopsis. TRENDS IN PLANT SCIENCE 2006; 11:167-75. [PMID: 16530461 DOI: 10.1016/j.tplants.2006.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 01/09/2006] [Accepted: 02/24/2006] [Indexed: 05/07/2023]
Abstract
Kinesins are a class of microtubule-associated proteins that possess a motor domain for binding to microtubules and, in general, allows movement along microtubules. In animal mitosis, they function in spindle formation, chromosome movement and in cytokinesis. In addition to the spindle, plants develop a preprophase band and a phragmoplast that might require multiple kinesins for construction and functioning. Indeed, several kinesins play a role in phragmoplast and cell plate dynamics. Surprisingly few kinesins have been associated with the spindle and the preprophase band. Analysis of expression datasets from synchronized cell cultures indicate that at least 23 kinesins are in some way implicated in mitosis-related processes. In this review, the function of kinesins in animal and plant mitoses are compared, and the divergence that originates from plant-specific aspects is highlighted.
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Affiliation(s)
- Marleen Vanstraelen
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, Technologiepark 927, B-9052 Gent, Belgium
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144
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Ma L, Zhao X, Zhu X. Mitosin/CENP-F in mitosis, transcriptional control, and differentiation. J Biomed Sci 2006; 13:205-13. [PMID: 16456711 DOI: 10.1007/s11373-005-9057-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Accepted: 12/22/2005] [Indexed: 01/03/2023] Open
Abstract
Mitosin/CENP-F is a large nuclear/kinetochore protein containing multiple leucine zipper motifs potentially for protein interactions. Its expression levels and subcellular localization patterns are regulated in a cell cycle-dependent manner. Recently, accumulating lines of evidence have suggested it a multifunctional protein involved in mitotic control, microtubule dynamics, transcriptional regulation, and muscle cell differentiation. Consistently, it is shown to interact directly with a variety of proteins including CENP-E, NudE/Nudel, ATF4, and Rb. Here we review the current progress and discuss possible mechanisms through which mitosin may function.
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Affiliation(s)
- Li Ma
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
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145
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Kapoor TM, Lampson MA, Hergert P, Cameron L, Cimini D, Salmon ED, McEwen BF, Khodjakov A. Chromosomes can congress to the metaphase plate before biorientation. Science 2006; 311:388-91. [PMID: 16424343 PMCID: PMC4768465 DOI: 10.1126/science.1122142] [Citation(s) in RCA: 323] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The stable propagation of genetic material during cell division depends on the congression of chromosomes to the spindle equator before the cell initiates anaphase. It is generally assumed that congression requires that chromosomes are connected to the opposite poles of the bipolar spindle ("bioriented"). In mammalian cells, we found that chromosomes can congress before becoming bioriented. By combining the use of reversible chemical inhibitors, live-cell light microscopy, and correlative electron microscopy, we found that monooriented chromosomes could glide toward the spindle equator alongside kinetochore fibers attached to other already bioriented chromosomes. This congression mechanism depended on the kinetochore-associated, plus end-directed microtubule motor CENP-E (kinesin-7).
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Affiliation(s)
- Tarun M. Kapoor
- Laboratory of Chemistry and Cell Biology, the Rockefeller University, New York, NY 10021, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Michael A. Lampson
- Laboratory of Chemistry and Cell Biology, the Rockefeller University, New York, NY 10021, USA
| | - Polla Hergert
- Division of Molecular Medicine, Wadsworth Center, Albany, NY 12201–0509, USA
| | - Lisa Cameron
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daniela Cimini
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - E. D. Salmon
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Bruce F. McEwen
- Division of Molecular Medicine, Wadsworth Center, Albany, NY 12201–0509, USA
| | - Alexey Khodjakov
- Laboratory of Chemistry and Cell Biology, the Rockefeller University, New York, NY 10021, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
- Division of Molecular Medicine, Wadsworth Center, Albany, NY 12201–0509, USA
- To whom correspondence should be addressed.
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146
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Yoon J, Kang Y, Kim K, Park J, Kim Y. Identification and purification of a soluble region of BubR1: a critical component of the mitotic checkpoint complex. Protein Expr Purif 2006; 44:1-9. [PMID: 15946858 DOI: 10.1016/j.pep.2005.04.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 04/14/2005] [Accepted: 04/26/2005] [Indexed: 10/25/2022]
Abstract
The mitotic checkpoint complex (MCC) ensures the fidelity of chromosomal segregation, by delaying the onset of anaphase until all sister chromatids have been properly attached to the mitotic spindle. In essence, this MCC-induced delay is achieved via the inhibition of the anaphase-promoting complex (APC). Among the components of the MCC, BubR1 plays two major roles in the functions of the mitotic checkpoint. First, BubR1 is able to inhibit APC activity, either by itself or as a component of the MCC, by sequestering a APC coactivator, known as Cdc20. Second, BubR1 activates mitotic checkpoint signaling cascades by binding to the centromere-associated protein E, a microtubule motor protein. Obtaining highly soluble BubR1 is a prerequisite for the study of its structure. BubR1 is a multi-domain protein, which includes a KEN box motif, a mad3-like region, a Bub3 binding domain, and a kinase domain. We obtained a soluble BubR1 construct using a three-step expression strategy. First, we obtained two constructs from BLAST sequence homology searches, both of which were expressed abundantly in the inclusion bodies. We then adjusted the lengths of the two constructs by secondary structure prediction, thereby generating partially soluble constructs. Third, we optimized the solubility of the two constructs by either chopping or adding a few residues at the C-terminus. Finally, we obtained a highly soluble BubR1 construct via the Escherichia coli expression system, which allowed for a yield of 10.8 mg/L culture. This report may provide insight into the design of highly soluble constructs of insoluble multi-domain proteins.
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Affiliation(s)
- Jongchul Yoon
- Division of Molecular Genomic Medicine, College of Medicine, Seoul National University, Yongon-Dong, Seoul 110-799, Korea
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147
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Affiliation(s)
- Rebecca Heald
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
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148
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Kanta H, Laprade L, Almutairi A, Pinto I. Suppressor analysis of a histone defect identifies a new function for the hda1 complex in chromosome segregation. Genetics 2006; 173:435-50. [PMID: 16415367 PMCID: PMC1461434 DOI: 10.1534/genetics.105.050559] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Histones are essential for the compaction of DNA into chromatin and therefore participate in all chromosomal functions. Specific mutations in HTA1, one of the two Saccharomyces cerevisiae genes encoding histone H2A, have been previously shown to cause chromosome segregation defects, including an increase in ploidy associated with altered pericentromeric chromatin structure, suggesting a role for histone H2A in kinetochore function. To identify proteins that may interact with histone H2A in the control of ploidy and chromosome segregation, we performed a genetic screen for suppressors of the increase-in-ploidy phenotype associated with one of the H2A mutations. We identified five genes, HHT1, MKS1, HDA1, HDA2, and HDA3, four of which encode proteins directly connected to chromatin function: histone H3 and each of the three subunits of the Hda1 histone deacetylase complex. Our results show that Hda3 has functions distinct from Hda2 and Hda1 and that it is required for normal chromosome segregation and cell cycle progression. In addition, HDA3 shows genetic interactions with kinetochore components, emphasizing a role in centromere function, and all three Hda proteins show association with centromeric DNA. These findings suggest that the Hda1 deacetylase complex affects histone function at the centromere and that Hda3 has a distinctive participation in chromosome segregation. Moreover, these suppressors provide the basis for future studies regarding histone function in chromosome segregation.
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Affiliation(s)
- Hasna Kanta
- Department of Biological Sciences, University of Arkansas, Fayetteville 72701, USA
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149
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Higgins AW, Gustashaw KM, Willard HF. Engineered human dicentric chromosomes show centromere plasticity. Chromosome Res 2005; 13:745-62. [PMID: 16331407 DOI: 10.1007/s10577-005-1009-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 09/13/2005] [Indexed: 11/26/2022]
Abstract
The centromere is essential for the faithful distribution of a cell's genetic material to subsequent generations. Despite intense scrutiny, the precise genetic and epigenetic basis for centromere function is still unknown. Here, we have used engineered dicentric human chromosomes to investigate mammalian centromere structure and function. We describe three classes of dicentric chromosomes isolated in different cell lines: functionally monocentric chromosomes, in which one of the two genetically identical centromeres is consistently inactivated; functionally dicentric chromosomes, in which both centromeres are consistently active; and dicentric chromosomes heterogeneous with respect to centromere activity. A study of serial single cell clones from heterogeneous cell lines revealed that while centromere activity is usually clonal, the centromere state (i.e. functionally monocentric or dicentric) in some lines can switch within a growing population of cells. Because pulsed field gel analysis indicated that the DNA at the centromeres of these chromosomes did not change detectably, this switching of the centromere state is most likely due to epigenetic changes. Inactivation of one of the two active centromeres in a functionally dicentric chromosome was observed in a percentage of cells after treatment with Trichostatin A, an inhibitor of histone deacetylation. This study provides evidence that the activity of human centromeres, while largely stable, can be subject to dynamic change, most likely due to epigenetic modification.
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Affiliation(s)
- Anne W Higgins
- Department of Genetics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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150
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Chan GK, Liu ST, Yen TJ. Kinetochore structure and function. Trends Cell Biol 2005; 15:589-98. [PMID: 16214339 DOI: 10.1016/j.tcb.2005.09.010] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Revised: 08/30/2005] [Accepted: 09/22/2005] [Indexed: 11/16/2022]
Abstract
The vertebrate kinetochore is a complex structure that specifies the attachments between the chromosomes and microtubules of the spindle and is thus essential for accurate chromosome segregation. Kinetochores are assembled on centromeric chromatin through complex pathways that are coordinated with the cell cycle. In the light of recent discoveries on how proteins assemble onto kinetochores and interact with each other, we review these findings in this article (which is part of the Chromosome Segregation and Aneuploidy series), and discuss their implications for the current mitotic checkpoint models - the template model and the two-step model. The template model proposes that Mad1-Mad2 at kinetochores acts as a template to change the conformation of another binding molecule of Mad2. This templated change in conformation is postulated as a mechanism for the amplification of the 'anaphase wait' signal. The two-step model proposes that the mitotic checkpoint complex (MCC) is the kinetochore-independent anaphase inhibitor, and the role of the unaligned kinetochore is to sensitize the anaphase-promoting complex/cyclosome (APC/C) to MCC-mediated inhibition.
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Affiliation(s)
- Gordon K Chan
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2.
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