51
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Kroupova A, Ackle F, Asanović I, Weitzer S, Boneberg FM, Faini M, Leitner A, Chui A, Aebersold R, Martinez J, Jinek M. Molecular architecture of the human tRNA ligase complex. eLife 2021; 10:e71656. [PMID: 34854379 PMCID: PMC8668186 DOI: 10.7554/elife.71656] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 12/01/2021] [Indexed: 01/23/2023] Open
Abstract
RtcB enzymes are RNA ligases that play essential roles in tRNA splicing, unfolded protein response, and RNA repair. In metazoa, RtcB functions as part of a five-subunit tRNA ligase complex (tRNA-LC) along with Ddx1, Cgi-99, Fam98B, and Ashwin. The human tRNA-LC or its individual subunits have been implicated in additional cellular processes including microRNA maturation, viral replication, DNA double-strand break repair, and mRNA transport. Here, we present a biochemical analysis of the inter-subunit interactions within the human tRNA-LC along with crystal structures of the catalytic subunit RTCB and the N-terminal domain of CGI-99. We show that the core of the human tRNA-LC is assembled from RTCB and the C-terminal alpha-helical regions of DDX1, CGI-99, and FAM98B, all of which are required for complex integrity. The N-terminal domain of CGI-99 displays structural homology to calponin-homology domains, and CGI-99 and FAM98B associate via their N-terminal domains to form a stable subcomplex. The crystal structure of GMP-bound RTCB reveals divalent metal coordination geometry in the active site, providing insights into its catalytic mechanism. Collectively, these findings shed light on the molecular architecture and mechanism of the human tRNA ligase complex and provide a structural framework for understanding its functions in cellular RNA metabolism.
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Affiliation(s)
- Alena Kroupova
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | - Fabian Ackle
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | - Igor Asanović
- Max Perutz Labs, Vienna BioCenter (VBC)ViennaAustria
| | | | | | - Marco Faini
- Department of Biology, Institute of Molecular Systems Biology, ETH ZurichZurichSwitzerland
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, ETH ZurichZurichSwitzerland
| | - Alessia Chui
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH ZurichZurichSwitzerland
| | | | - Martin Jinek
- Department of Biochemistry, University of ZurichZurichSwitzerland
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52
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Pajpach F, Wu T, Shearwin-Whyatt L, Jones K, Grützner F. Flavors of Non-Random Meiotic Segregation of Autosomes and Sex Chromosomes. Genes (Basel) 2021; 12:genes12091338. [PMID: 34573322 PMCID: PMC8471020 DOI: 10.3390/genes12091338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 12/14/2022] Open
Abstract
Segregation of chromosomes is a multistep process occurring both at mitosis and meiosis to ensure that daughter cells receive a complete set of genetic information. Critical components in the chromosome segregation include centromeres, kinetochores, components of sister chromatid and homologous chromosomes cohesion, microtubule organizing centres, and spindles. Based on the cytological work in the grasshopper Brachystola, it has been accepted for decades that segregation of homologs at meiosis is fundamentally random. This ensures that alleles on chromosomes have equal chance to be transmitted to progeny. At the same time mechanisms of meiotic drive and an increasing number of other examples of non-random segregation of autosomes and sex chromosomes provide insights into the underlying mechanisms of chromosome segregation but also question the textbook dogma of random chromosome segregation. Recent advances provide a better understanding of meiotic drive as a prominent force where cellular and chromosomal changes allow autosomes to bias their segregation. Less understood are mechanisms explaining observations that autosomal heteromorphism may cause biased segregation and regulate alternating segregation of multiple sex chromosome systems or translocation heterozygotes as an extreme case of non-random segregation. We speculate that molecular and cytological mechanisms of non-random segregation might be common in these cases and that there might be a continuous transition between random and non-random segregation which may play a role in the evolution of sexually antagonistic genes and sex chromosome evolution.
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Affiliation(s)
- Filip Pajpach
- School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia; (F.P.); (L.S.-W.)
| | - Tianyu Wu
- Department of Central Laboratory, Clinical Laboratory, Jing’an District Centre Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China;
| | - Linda Shearwin-Whyatt
- School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia; (F.P.); (L.S.-W.)
| | - Keith Jones
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RH, UK;
| | - Frank Grützner
- School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia; (F.P.); (L.S.-W.)
- Correspondence:
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53
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Aurora B Tension Sensing Mechanisms in the Kinetochore Ensure Accurate Chromosome Segregation. Int J Mol Sci 2021; 22:ijms22168818. [PMID: 34445523 PMCID: PMC8396173 DOI: 10.3390/ijms22168818] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 11/29/2022] Open
Abstract
The accurate segregation of chromosomes is essential for the survival of organisms and cells. Mistakes can lead to aneuploidy, tumorigenesis and congenital birth defects. The spindle assembly checkpoint ensures that chromosomes properly align on the spindle, with sister chromatids attached to microtubules from opposite poles. Here, we review how tension is used to identify and selectively destabilize incorrect attachments, and thus serves as a trigger of the spindle assembly checkpoint to ensure fidelity in chromosome segregation. Tension is generated on properly attached chromosomes as sister chromatids are pulled in opposing directions but resisted by centromeric cohesin. We discuss the role of the Aurora B kinase in tension-sensing and explore the current models for translating mechanical force into Aurora B-mediated biochemical signals that regulate correction of chromosome attachments to the spindle.
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54
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Kops GJPL, Snel B, Tromer EC. Evolutionary Dynamics of the Spindle Assembly Checkpoint in Eukaryotes. Curr Biol 2021; 30:R589-R602. [PMID: 32428500 DOI: 10.1016/j.cub.2020.02.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The tremendous diversity in eukaryotic life forms can ultimately be traced back to evolutionary modifications at the level of molecular networks. Deep understanding of these modifications will not only explain cellular diversity, but will also uncover different ways to execute similar processes and expose the evolutionary 'rules' that shape the molecular networks. Here, we review the evolutionary dynamics of the spindle assembly checkpoint (SAC), a signaling network that guards fidelity of chromosome segregation. We illustrate how the interpretation of divergent SAC systems in eukaryotic species is facilitated by combining detailed molecular knowledge of the SAC and extensive comparative genome analyses. Ultimately, expanding this to other core cellular systems and experimentally interrogating such systems in organisms from all major lineages may start outlining the routes to and eventual manifestation of the cellular diversity of eukaryotic life.
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Affiliation(s)
- Geert J P L Kops
- Oncode Institute, Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences) and University Medical Centre Utrecht, Utrecht, The Netherlands.
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands.
| | - Eelco C Tromer
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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55
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Gui P, Sedzro DM, Yuan X, Liu S, Hei M, Tian W, Zohbi N, Wang F, Yao Y, Aikhionbare FO, Gao X, Wang D, Yao X, Dou Z. Mps1 dimerization and multisite interactions with Ndc80 complex enable responsive spindle assembly checkpoint signaling. J Mol Cell Biol 2021; 12:486-498. [PMID: 32219319 PMCID: PMC7493027 DOI: 10.1093/jmcb/mjaa006] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/13/2020] [Accepted: 03/18/2020] [Indexed: 12/21/2022] Open
Abstract
Error-free mitosis depends on accurate chromosome attachment to spindle microtubules, which is monitored by the spindle assembly checkpoint (SAC) signaling. As an upstream factor of SAC, the precise and dynamic kinetochore localization of Mps1 kinase is critical for initiating and silencing SAC signaling. However, the underlying molecular mechanism remains elusive. Here, we demonstrated that the multisite interactions between Mps1 and Ndc80 complex (Ndc80C) govern Mps1 kinetochore targeting. Importantly, we identified direct interaction between Mps1 tetratricopeptide repeat domain and Ndc80C. We further identified that Mps1 C-terminal fragment, which contains the protein kinase domain and C-tail, enhances Mps1 kinetochore localization. Mechanistically, Mps1 C-terminal fragment mediates its dimerization. Perturbation of C-tail attenuates the kinetochore targeting and activity of Mps1, leading to aberrant mitosis due to compromised SAC function. Taken together, our study highlights the importance of Mps1 dimerization and multisite interactions with Ndc80C in enabling responsive SAC signaling.
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Affiliation(s)
- Ping Gui
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China.,Keck Center for Cellular Dynamics and Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Divine M Sedzro
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Xiao Yuan
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Sikai Liu
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Mohan Hei
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wei Tian
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Najdat Zohbi
- Keck Center for Cellular Dynamics and Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Fangwei Wang
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Yihan Yao
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Felix O Aikhionbare
- Keck Center for Cellular Dynamics and Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Xinjiao Gao
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Dongmei Wang
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Xuebiao Yao
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Zhen Dou
- MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
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56
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Denarier E, Ecklund KH, Berthier G, Favier A, O'Toole ET, Gory-Fauré S, De Macedo L, Delphin C, Andrieux A, Markus SM, Boscheron C. Modeling a disease-correlated tubulin mutation in budding yeast reveals insight into MAP-mediated dynein function. Mol Biol Cell 2021; 32:ar10. [PMID: 34379441 PMCID: PMC8684761 DOI: 10.1091/mbc.e21-05-0237] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutations in the genes that encode α- and β-tubulin underlie many neurological diseases, most notably malformations in cortical development. In addition to revealing the molecular basis for disease etiology, studying such mutations can provide insight into microtubule function and the role of the large family of microtubule effectors. In this study, we use budding yeast to model one such mutation—Gly436Arg in α-tubulin, which is causative of malformations in cortical development—in order to understand how it impacts microtubule function in a simple eukaryotic system. Using a combination of in vitro and in vivo methodologies, including live cell imaging and electron tomography, we find that the mutant tubulin is incorporated into microtubules, causes a shift in α-tubulin isotype usage, and dramatically enhances dynein activity, which leads to spindle-positioning defects. We find that the basis for the latter phenotype is an impaired interaction between She1—a dynein inhibitor—and the mutant microtubules. In addition to revealing the natural balance of α-tubulin isotype utilization in cells, our results provide evidence of an impaired interaction between microtubules and a dynein regulator as a consequence of a tubulin mutation and sheds light on a mechanism that may be causative of neurodevelopmental diseases.
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Affiliation(s)
- E Denarier
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
| | - K H Ecklund
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States
| | - G Berthier
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
| | - A Favier
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
| | - E T O'Toole
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, Colorado, United States
| | - S Gory-Fauré
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
| | - L De Macedo
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
| | - C Delphin
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
| | - A Andrieux
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
| | - S M Markus
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States
| | - C Boscheron
- Univ. Grenoble Alpes, CEA, CNRS, GIN, IBS, Inserm, IRIG, F-38000 Grenoble, France
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57
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Murachelli AG, Damaskos G, Perrakis A. CCD 2: design constructs for protein expression, the easy way. Acta Crystallogr D Struct Biol 2021; 77:992-1000. [PMID: 34342272 PMCID: PMC8329859 DOI: 10.1107/s2059798321005891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/07/2021] [Indexed: 11/10/2022] Open
Abstract
Studying the function or structure of proteins usually requires the generation of many protein-truncation constructs for recombinant expression, which is a tedious and error-prone job. CCD2 is a software tool designed to facilitate and automate this task. CCD2 helps scientists by aggregating the information necessary to design protein-expression constructs. This information includes sequence conservation, secondary structure prediction, domain(s) and disorder detection, post-translational modifications and information on similar (domain) structures that are available in the Protein Data Bank. CCD2 then allows users to easily choose the boundaries for protein constructs and automatically generates the primers necessary for construct amplification by polymerase chain reaction. Finally, CCD2 provides a quick analysis of the properties of the chosen constructs, together with their DNA vector maps for bookkeeping. The features of CCD2 are discussed step by step, showing that it can be a useful tool for laboratories that engage in recombinant protein production for any type of experiment, and in particular for structural biology studies.
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Affiliation(s)
- Andrea Giovanni Murachelli
- Oncode Institute and Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - George Damaskos
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Anastassis Perrakis
- Oncode Institute and Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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58
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Li J, Wang Y, Zou W, Jian L, Fu Y, Zhao J. AtNUF2 modulates spindle microtubule organization and chromosome segregation during mitosis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:801-816. [PMID: 33993566 DOI: 10.1111/tpj.15347] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
The NDC80 complex is a conserved eukaryotic complex composed of four subunits (NUF2, SPC25, NDC80, and SPC24). In yeast and animal cells, the complex is located at the outer layer of the kinetochore, connecting the inner layer of the kinetochore and spindle microtubules (MTs) during cell division. In higher plants, the relationship of the NDC80 complex with MTs is still unclear. In this study, we characterized the biological function of AtNUF2, a subunit of the Arabidopsis NDC80 complex. We found that AtNUF2 is widely expressed in various organs, especially in different stages of embryonic development. It was verified that AtNUF2 co-localized with α-tubulin on MTs during mitosis by immunohistochemical assays. Mutation of AtNUF2 led to severe mitotic defects, not only in the embryo and endosperm, but also in seedlings, resulting in seed abortion and stagnating seedling growth. Furthermore, the biological function of AtNUF2 was studied using partially complemented nuf2-3/-DD45;ABI3pro::AtNUF2 (nuf2-3/-DA ) seedlings. The chromosome bridge and lagging chromatids occurred in nuf2-3/-DA root apical meristem cells, along with aberration of spindle MTs, resulting in blocked root growth. Meanwhile, the direct binding of AtNUF2 and AtSPC25 to MTs was determined by an MT co-sedimentation assay in vitro. This study revealed the function of AtNUF2 in mitosis and the underlying mechanisms, modulating spindle MT organization and ensuring chromosome segregation during embryo, endosperm, and root development, laying the foundation for subsequent research of the NDC80 complex.
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Affiliation(s)
- Jin Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yutao Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Wenxuan Zou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Liufang Jian
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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59
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Ferreira LT, Maiato H. Prometaphase. Semin Cell Dev Biol 2021; 117:52-61. [PMID: 34127384 DOI: 10.1016/j.semcdb.2021.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/28/2022]
Abstract
The establishment of a metaphase plate in which all chromosomes are attached to mitotic spindle microtubules and aligned at the cell equator is required for faithful chromosome segregation in metazoans. The achievement of this configuration relies on the precise coordination between several concurrent mechanisms that start upon nuclear envelope breakdown, mediate chromosome capture at their kinetochores during mitotic spindle assembly and culminate with the congression of all chromosomes to the spindle equator. This period is called 'prometaphase'. Because the nature of chromosome capture by mitotic spindle microtubules is error prone, the cell is provided of error correction mechanisms that sense and correct most erroneous kinetochore-microtubule attachments before committing to separate sister chromatids in anaphase. In this review, aimed for newcomers in the field, more than providing an exhaustive mechanistic coverage of each and every concurrent mechanism taking place during prometaphase, we provide an integrative overview of these processes that ultimately promote the subsequent faithful segregation of chromosomes during mitosis.
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Affiliation(s)
- Luísa T Ferreira
- Chromosome Instability & Dynamics Group, i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
| | - Helder Maiato
- Chromosome Instability & Dynamics Group, i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; Cell Division Group, Experimental Biology Unit, Department of Biomedicine, Faculdade de Medicina, Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal.
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60
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Barisic M, Rajendraprasad G. Mitotic poleward flux: Finding balance between microtubule dynamics and sliding. Bioessays 2021; 43:e2100079. [PMID: 34085708 DOI: 10.1002/bies.202100079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/13/2021] [Accepted: 05/21/2021] [Indexed: 12/13/2022]
Abstract
Continuous poleward motion of microtubules in metazoan mitotic spindles has been fascinating generations of cell biologists over the last several decades. In human cells, this so-called poleward flux was recently shown to be driven by the coordinated action of four mitotic kinesins. The sliding activities of kinesin-5/EG5 and kinesin-12/KIF15 are sequentially supported by kinesin-7/CENP-E at kinetochores and kinesin-4/KIF4A on chromosome arms, with the individual contributions peaking during prometaphase and metaphase, respectively. Although recent data elucidate the molecular mechanism underlying this cellular phenomenon, the functional roles of microtubule poleward flux during cell division remain largely elusive. Here, we discuss potential contribution of microtubule flux engine to various essential processes at different stages of mitosis.
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Affiliation(s)
- Marin Barisic
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Copenhagen, Denmark.,Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Girish Rajendraprasad
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Copenhagen, Denmark
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61
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Huang R, Liu J, Li H, Zheng L, Jin H, Zhang Y, Ma W, Su J, Wang M, Yang K. Identification of Hub Genes and Their Correlation With Immune Infiltration Cells in Hepatocellular Carcinoma Based on GEO and TCGA Databases. Front Genet 2021; 12:647353. [PMID: 33995482 PMCID: PMC8120231 DOI: 10.3389/fgene.2021.647353] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 04/06/2021] [Indexed: 12/12/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a primary liver cancer with extremely high mortality in worldwide. HCC is hard to diagnose and has a poor prognosis due to the less understanding of the molecular pathological mechanisms and the regulation mechanism on immune cell infiltration during hepatocarcinogenesis. Herein, by performing multiple bioinformatics analysis methods, including the RobustRankAggreg (RRA) rank analysis, weighted gene co-expression network analysis (WGCNA), and a devolution algorithm (CIBERSORT), we first identified 14 hub genes (NDC80, DLGAP5, BUB1B, KIF20A, KIF2C, KIF11, NCAPG, NUSAP1, PBK, ASPM, FOXM1, TPX2, UBE2C, and PRC1) in HCC, whose expression levels were significantly up-regulated and negatively correlated with overall survival time. Moreover, we found that the expression of these hub genes was significantly positively correlated with immune infiltration cells, including regulatory T cells (Treg), T follicular helper (TFH) cells, macrophages M0, but negatively correlated with immune infiltration cells including monocytes. Among these hub genes, KIF2C and UBE2C showed the most significant correlation and were associated with immune cell infiltration in HCC, which was speculated as the potential prognostic biomarker for guiding immunotherapy.
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Affiliation(s)
- Rui Huang
- College of Medicine, Northwest Minzu University, Lanzhou, China
| | - Jinying Liu
- College of Medicine, Northwest Minzu University, Lanzhou, China
| | - Hui Li
- Lanzhou Maternity and Child Health Care Hospital, Lanzhou, China
| | - Lierui Zheng
- College of Medicine, Northwest Minzu University, Lanzhou, China
| | - Haojun Jin
- College of Medicine, Northwest Minzu University, Lanzhou, China
| | - Yaqing Zhang
- College of Medicine, Northwest Minzu University, Lanzhou, China
| | - Wei Ma
- College of Medicine, Northwest Minzu University, Lanzhou, China
| | - Junhong Su
- Medical Faculty, Kunming University of Science and Technology, Kunming, China
| | - Min Wang
- College of Medicine, Northwest Minzu University, Lanzhou, China
| | - Kun Yang
- Lanzhou University Second Hospital, Lanzhou, China
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62
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Ludzia P, Lowe ED, Marcianò G, Mohammed S, Redfield C, Akiyoshi B. Structural characterization of KKT4, an unconventional microtubule-binding kinetochore protein. Structure 2021; 29:1014-1028.e8. [PMID: 33915106 PMCID: PMC8443799 DOI: 10.1016/j.str.2021.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/17/2021] [Accepted: 04/08/2021] [Indexed: 01/01/2023]
Abstract
The kinetochore is the macromolecular machinery that drives chromosome segregation by interacting with spindle microtubules. Kinetoplastids (such as Trypanosoma brucei), a group of evolutionarily divergent eukaryotes, have a unique set of kinetochore proteins that lack any significant homology to canonical kinetochore components. To date, KKT4 is the only kinetoplastid kinetochore protein that is known to bind microtubules. Here we use X-ray crystallography, NMR spectroscopy, and crosslinking mass spectrometry to characterize the structure and dynamics of KKT4. We show that its microtubule-binding domain consists of a coiled-coil structure followed by a positively charged disordered tail. The structure of the C-terminal BRCT domain of KKT4 reveals that it is likely a phosphorylation-dependent protein-protein interaction domain. The BRCT domain interacts with the N-terminal region of the KKT4 microtubule-binding domain and with a phosphopeptide derived from KKT8. Taken together, these results provide structural insights into the unconventional kinetoplastid kinetochore protein KKT4. Structures of microtubule-binding and BRCT domains in KKT4 are reported The microtubule-binding domain consists of a coiled coil and a disordered tail KKT4 interacts with microtubules via a basic surface at the coiled-coil N terminus KKT4 has a phosphopeptide-binding BRCT domain
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Affiliation(s)
- Patryk Ludzia
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Edward D Lowe
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Gabriele Marcianò
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Shabaz Mohammed
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Bungo Akiyoshi
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
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63
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Doodhi H, Kasciukovic T, Clayton L, Tanaka TU. Aurora B switches relative strength of kinetochore-microtubule attachment modes for error correction. J Cell Biol 2021; 220:211981. [PMID: 33851957 PMCID: PMC8050843 DOI: 10.1083/jcb.202011117] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/03/2021] [Accepted: 03/17/2021] [Indexed: 11/24/2022] Open
Abstract
To establish chromosome biorientation, aberrant kinetochore–microtubule interaction must be resolved (error correction) by Aurora B kinase. Aurora B differentially regulates kinetochore attachment to the microtubule plus end and its lateral side (end-on and lateral attachment, respectively). However, it is still unclear how kinetochore–microtubule interactions are exchanged during error correction. Here, we reconstituted the budding yeast kinetochore–microtubule interface in vitro by attaching the Ndc80 complexes to nanobeads. These Ndc80C nanobeads recapitulated in vitro the lateral and end-on attachments of authentic kinetochores on dynamic microtubules loaded with the Dam1 complex. This in vitro assay enabled the direct comparison of lateral and end-on attachment strength and showed that Dam1 phosphorylation by Aurora B makes the end-on attachment weaker than the lateral attachment. Similar reconstitutions with purified kinetochore particles were used for comparison. We suggest the Dam1 phosphorylation weakens interaction with the Ndc80 complex, disrupts the end-on attachment, and promotes the exchange to a new lateral attachment, leading to error correction.
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Affiliation(s)
- Harinath Doodhi
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Taciana Kasciukovic
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Lesley Clayton
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Tomoyuki U Tanaka
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
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64
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Brusini L, D'Archivio S, McDonald J, Wickstead B. Trypanosome KKIP1 Dynamically Links the Inner Kinetochore to a Kinetoplastid Outer Kinetochore Complex. Front Cell Infect Microbiol 2021; 11:641174. [PMID: 33834005 PMCID: PMC8023272 DOI: 10.3389/fcimb.2021.641174] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 02/16/2021] [Indexed: 02/02/2023] Open
Abstract
Kinetochores perform an essential role in eukaryotes, coupling chromosomes to the mitotic spindle. In model organisms they are composed of a centromere-proximal inner kinetochore and an outer kinetochore network that binds to microtubules. In spite of universal function, the composition of kinetochores in extant eukaryotes differs greatly. In trypanosomes and other Kinetoplastida, kinetochores are extremely divergent, with most components showing no detectable similarity to proteins in other systems. They may also be very different functionally, potentially binding to the spindle directly via an inner-kinetochore protein. However, we do not know the extent of the trypanosome kinetochore, and proteins interacting with a highly divergent Ndc80/Nuf2-like protein (KKIP1) suggest the existence of more centromere-distal complexes. Here we use quantitative proteomics from multiple start-points to define a stable 9-protein kinetoplastid outer kinetochore (KOK) complex. This complex incorporates proteins recruited from other nuclear processes, exemplifying the role of moonlighting proteins in kinetochore evolution. The outer kinetochore complex is physically distinct from inner-kinetochore proteins, but nanometer-scale label separation shows that KKIP1 bridges the two plates in the same orientation as Ndc80. Moreover, KKIP1 exhibits substantial elongation at metaphase, altering kinetochore structure in a manner consistent with pulling at the outer plate. Together, these data suggest that the KKIP1/KOK likely constitute the extent of the trypanosome outer kinetochore and that this assembly binds to the spindle with sufficient strength to stretch the kinetochore, showing design parallels may exist in organisms with very different kinetochore composition.
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Affiliation(s)
- Lorenzo Brusini
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Simon D'Archivio
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.,Sygnature Discovery, Nottingham, United Kingdom
| | - Jennifer McDonald
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.,Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Bill Wickstead
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
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65
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Chen J, Ünal E. Meiotic regulation of the Ndc80 complex composition and function. Curr Genet 2021; 67:511-518. [PMID: 33745061 PMCID: PMC8254699 DOI: 10.1007/s00294-021-01174-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
This review describes the current models for how the subunit abundance of the Ndc80 complex, a key kinetochore component, is regulated in budding yeast and metazoan meiosis. The past decades of kinetochore research have established the Ndc80 complex to be a key microtubule interactor and a central hub for regulating chromosome segregation. Recent studies further demonstrate that Ndc80 is the limiting kinetochore subunit that dictates the timing of kinetochore activation in budding yeast meiosis. Here, we discuss the molecular circuits that regulate Ndc80 protein synthesis and degradation in budding yeast meiosis and compare the findings with those from metazoans. We envision the regulatory principles discovered in budding yeast to be conserved in metazoans, thereby providing guidance into future investigations on kinetochore regulation in human health and disease.
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Affiliation(s)
- Jingxun Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - Elçin Ünal
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA.
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66
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Shake It Off: The Elimination of Erroneous Kinetochore-Microtubule Attachments and Chromosome Oscillation. Int J Mol Sci 2021; 22:ijms22063174. [PMID: 33804687 PMCID: PMC8003821 DOI: 10.3390/ijms22063174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/18/2021] [Indexed: 01/17/2023] Open
Abstract
Cell proliferation and sexual reproduction require the faithful segregation of chromosomes. Chromosome segregation is driven by the interaction of chromosomes with the spindle, and the attachment of chromosomes to the proper spindle poles is essential. Initial attachments are frequently erroneous due to the random nature of the attachment process; however, erroneous attachments are selectively eliminated. Proper attachment generates greater tension at the kinetochore than erroneous attachments, and it is thought that attachment selection is dependent on this tension. However, studies of meiotic chromosome segregation suggest that attachment elimination cannot be solely attributed to tension, and the precise mechanism of selective elimination of erroneous attachments remains unclear. During attachment elimination, chromosomes oscillate between the spindle poles. A recent study on meiotic chromosome segregation in fission yeast has suggested that attachment elimination is coupled to chromosome oscillation. In this review, the possible contribution of chromosome oscillation in the elimination of erroneous attachment is discussed in light of the recent finding.
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67
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Uehara DT, Mitsubuchi H, Inazawa J. A missense variant in NUF2, a component of the kinetochore NDC80 complex, causes impaired chromosome segregation and aneuploidy associated with microcephaly and short stature. Hum Genet 2021; 140:1047-1060. [PMID: 33721060 DOI: 10.1007/s00439-021-02273-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/28/2021] [Indexed: 12/11/2022]
Abstract
Mutations in proteins involved in cell division and chromosome segregation, such as microtubule-regulating, centrosomal and kinetochore proteins, are associated with microcephaly and/or short stature. In particular, the kinetochore plays an essential role in mitosis and cell division by mediating connections between chromosomal DNA and spindle microtubules. To date, only a few genes encoding proteins of the kinetochore complex have been identified as causes of syndromes that include microcephaly. We report a male patient with a rare de novo missense variant in NUF2, after trio whole-exome sequencing analysis. The patient presented with microcephaly and short stature, with additional features, such as bilateral vocal cord paralysis, micrognathia and atrial septal defect. NUF2 encodes a subunit of the NDC80 complex in the outer kinetochore, important for correct microtubule binding and spindle assembly checkpoint. The mutated residue is buried at the calponin homology (CH) domain at the N-terminus of NUF2, which interacts with the N-terminus of NDC80. The variant caused the loss of hydrophobic interactions in the core of the CH domain of NUF2, thereby impairing the stability of NDC80-NUF2. Analysis using a patient-derived lymphoblastoid cell line revealed markedly reduced protein levels of both NUF2 and NDC80, aneuploidy, increased micronuclei formation and spindle abnormality. Our findings suggest that NUF2 may be the first member of the NDC80 complex to be associated with a human disorder.
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Affiliation(s)
- Daniela Tiaki Uehara
- Department of Molecular Cytogenetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Hiroshi Mitsubuchi
- Department of Neonatology, Kumamoto University Hospital, Kumamoto, Japan
| | - Johji Inazawa
- Department of Molecular Cytogenetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
- Bioresource Research Center, Tokyo Medical and Dental University, Tokyo, Japan.
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68
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Gene Co-Expression Analysis of Human RNASEH2A Reveals Functional Networks Associated with DNA Replication, DNA Damage Response, and Cell Cycle Regulation. BIOLOGY 2021; 10:biology10030221. [PMID: 33805806 PMCID: PMC7998727 DOI: 10.3390/biology10030221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 03/10/2021] [Indexed: 12/22/2022]
Abstract
Simple Summary RNASEH2A is the catalytic subunit of the ribonuclease (RNase) H2 ternary complex that plays an important role in maintaining DNA stability in cells. Recent studies have shown that the RNASEH2A subunit alone is highly expressed in certain cancer cell types. Via a series of bioinformatics approaches, we found that RNASEH2A is highly expressed in human proliferative tissues and many cancers. Our analyses reveal a possible involvement of RNASEH2A in cell cycle regulation in addition to its well established role in DNA replication and DNA repair. Our findings underscore that RNASEH2A could serve as a biomarker for cancer diagnosis and a therapeutic target. Abstract Ribonuclease (RNase) H2 is a key enzyme for the removal of RNA found in DNA-RNA hybrids, playing a fundamental role in biological processes such as DNA replication, telomere maintenance, and DNA damage repair. RNase H2 is a trimer composed of three subunits, RNASEH2A being the catalytic subunit. RNASEH2A expression levels have been shown to be upregulated in transformed and cancer cells. In this study, we used a bioinformatics approach to identify RNASEH2A co-expressed genes in different human tissues to underscore biological processes associated with RNASEH2A expression. Our analysis shows functional networks for RNASEH2A involvement such as DNA replication and DNA damage response and a novel putative functional network of cell cycle regulation. Further bioinformatics investigation showed increased gene expression in different types of actively cycling cells and tissues, particularly in several cancers, supporting a biological role for RNASEH2A but not for the other two subunits of RNase H2 in cell proliferation. Mass spectrometry analysis of RNASEH2A-bound proteins identified players functioning in cell cycle regulation. Additional bioinformatic analysis showed that RNASEH2A correlates with cancer progression and cell cycle related genes in Cancer Cell Line Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA) Pan Cancer datasets and supported our mass spectrometry findings.
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69
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Zahm JA, Stewart MG, Carrier JS, Harrison SC, Miller MP. Structural basis of Stu2 recruitment to yeast kinetochores. eLife 2021; 10:e65389. [PMID: 33591274 PMCID: PMC7909949 DOI: 10.7554/elife.65389] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/15/2021] [Indexed: 12/02/2022] Open
Abstract
Chromosome segregation during cell division requires engagement of kinetochores of sister chromatids with microtubules emanating from opposite poles. As the corresponding microtubules shorten, these 'bioriented' sister kinetochores experience tension-dependent stabilization of microtubule attachments. The yeast XMAP215 family member and microtubule polymerase, Stu2, associates with kinetochores and contributes to tension-dependent stabilization in vitro. We show here that a C-terminal segment of Stu2 binds the four-way junction of the Ndc80 complex (Ndc80c) and that residues conserved both in yeast Stu2 orthologs and in their metazoan counterparts make specific contacts with Ndc80 and Spc24. Mutations that perturb this interaction prevent association of Stu2 with kinetochores, impair cell viability, produce biorientation defects, and delay cell cycle progression. Ectopic tethering of the mutant Stu2 species to the Ndc80c junction restores wild-type function in vivo. These findings show that the role of Stu2 in tension-sensing depends on its association with kinetochores by binding with Ndc80c.
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Affiliation(s)
- Jacob A Zahm
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Howard Hughes Medical InstituteBostonUnited States
| | - Michael G Stewart
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Joseph S Carrier
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Howard Hughes Medical InstituteBostonUnited States
| | - Matthew P Miller
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
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70
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Geraghty Z, Barnard C, Uluocak P, Gruneberg U. The association of Plk1 with the astrin-kinastrin complex promotes formation and maintenance of a metaphase plate. J Cell Sci 2021; 134:jcs251025. [PMID: 33288550 PMCID: PMC7803464 DOI: 10.1242/jcs.251025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/30/2020] [Indexed: 11/20/2022] Open
Abstract
Errors in mitotic chromosome segregation can lead to DNA damage and aneuploidy, both hallmarks of cancer. To achieve synchronous error-free segregation, mitotic chromosomes must align at the metaphase plate with stable amphitelic attachments to microtubules emanating from opposing spindle poles. The astrin-kinastrin (astrin is also known as SPAG5 and kinastrin as SKAP) complex, also containing DYNLL1 and MYCBP, is a spindle and kinetochore protein complex with important roles in bipolar spindle formation, chromosome alignment and microtubule-kinetochore attachment. However, the molecular mechanisms by which astrin-kinastrin fulfils these diverse roles are not fully understood. Here, we characterise a direct interaction between astrin and the mitotic kinase Plk1. We identify the Plk1-binding site on astrin as well as four Plk1 phosphorylation sites on astrin. Regulation of astrin by Plk1 is dispensable for bipolar spindle formation and bulk chromosome congression, but promotes stable microtubule-kinetochore attachments and metaphase plate maintenance. It is known that Plk1 activity is required for effective microtubule-kinetochore attachment formation, and we suggest that astrin phosphorylation by Plk1 contributes to this process.
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Affiliation(s)
- Zoë Geraghty
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Christina Barnard
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Pelin Uluocak
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Ulrike Gruneberg
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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71
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Chen YJ, You GR, Lai MY, Lu LS, Chen CY, Ting LL, Lee HL, Kanno Y, Chiou JF, Cheng AJ. A Combined Systemic Strategy for Overcoming Cisplatin Resistance in Head and Neck Cancer: From Target Identification to Drug Discovery. Cancers (Basel) 2020; 12:cancers12113482. [PMID: 33238517 PMCID: PMC7700594 DOI: 10.3390/cancers12113482] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/02/2020] [Accepted: 11/21/2020] [Indexed: 12/24/2022] Open
Abstract
Simple Summary The efficiency of cisplatin is limited by drug resistance in head–neck cancer (HNC) patients. In this study, we established a cisplatin resistance (CR) cell model, generated CR related transcriptome profiling, and combined application of bioinformatics methodology to discover a possible way to overcome CR. Analysis of the functional pathway revealed that mitotic division is a novel mechanism significantly contributing to CR. Spindle pole body component 25 (SPC25), a kinetochore protein, was overexpressed in CR cells and significantly correlated with worse HNC patient survival. The silencing of SPC25 increased cisplatin sensitivity and reduced cancer stemness property. Integration of CR transcriptome profiling and drug database discovered a natural extract compound, celastrol, possessing a potent cytotoxic effect in CR cells to reverse CR. Thus, we combined systemic strategies to demonstrated that a novel biological process (mitotic cell division), a hub gene (SPC25), and a natural compound (celastrol) as novel strategies for the treatment of refractory HNC. Abstract Cisplatin is the first-line chemotherapy agent for head and neck cancer (HNC), but its therapeutic effects are hampered by its resistance. In this study, we employed systemic strategies to overcome cisplatin resistance (CR) in HNC. CR cells derived from isogenic HNC cell lines were generated. The CR related hub genes, functional mechanisms, and the sensitizing candidates were globally investigated by transcriptomic and bioinformatic analyses. Clinically, the prognostic significance was assessed by the Kaplan–Meier method. Cellular and molecular techniques, including cell viability assay, tumorsphere formation assay, RT-qPCR, and immunoblot, were used. Results showed that these CR cells possessed highly invasive and stem-like properties. A total of 647 molecules was identified, and the mitotic division exhibited a novel functional mechanism significantly related to CR. A panel of signature molecules, MSRB3, RHEB, ULBP1, and spindle pole body component 25 (SPC25), was found to correlate with poor prognosis in HNC patients. SPC25 was further shown as a prominent molecule, which markedly suppressed cancer stemness and attenuated CR after silencing. Celastrol, a nature extract compound, was demonstrated to effectively inhibit SPC25 expression and reverse CR phenotype. In conclusion, the development of SPC25 inhibitors, such as the application of celastrol, maybe a novel strategy to sensitize cisplatin for the treatment of refractory HNC.
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Affiliation(s)
- Yin-Ju Chen
- Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan; (Y.-J.C.); (L.-S.L.)
- International Ph.D. Program in Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan
- Department of Radiation Oncology, Taipei Medical University Hospital, Taipei 11031, Taiwan; (L.-L.T.); (H.-L.L.); (J.-F.C.)
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Guo-Rung You
- Department of Medical Biotechnology, Medical College, Chang Gung University, Taoyuan 33302, Taiwan; (G.-R.Y.); (M.-Y.L.)
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Meng-Yu Lai
- Department of Medical Biotechnology, Medical College, Chang Gung University, Taoyuan 33302, Taiwan; (G.-R.Y.); (M.-Y.L.)
| | - Long-Sheng Lu
- Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan; (Y.-J.C.); (L.-S.L.)
- International Ph.D. Program in Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan
- Department of Radiation Oncology, Taipei Medical University Hospital, Taipei 11031, Taiwan; (L.-L.T.); (H.-L.L.); (J.-F.C.)
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Chang-Yu Chen
- Division of Molecular Regulation of Inflammatory and Immune Disease, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba 278-0022, Japan; (C.-Y.C.); (Y.K.)
- Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
| | - Lai-Lei Ting
- Department of Radiation Oncology, Taipei Medical University Hospital, Taipei 11031, Taiwan; (L.-L.T.); (H.-L.L.); (J.-F.C.)
| | - Hsin-Lun Lee
- Department of Radiation Oncology, Taipei Medical University Hospital, Taipei 11031, Taiwan; (L.-L.T.); (H.-L.L.); (J.-F.C.)
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Taipei Cancer Center, Taipei Medical University, Taipei 11031, Taiwan
| | - Yuzuka Kanno
- Division of Molecular Regulation of Inflammatory and Immune Disease, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba 278-0022, Japan; (C.-Y.C.); (Y.K.)
- Department of Medicinal and Life Sciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba 278-0022, Japan
| | - Jeng-Fong Chiou
- Department of Radiation Oncology, Taipei Medical University Hospital, Taipei 11031, Taiwan; (L.-L.T.); (H.-L.L.); (J.-F.C.)
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Taipei Cancer Center, Taipei Medical University, Taipei 11031, Taiwan
| | - Ann-Joy Cheng
- Department of Medical Biotechnology, Medical College, Chang Gung University, Taoyuan 33302, Taiwan; (G.-R.Y.); (M.-Y.L.)
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Radiation Oncology, Chang Gung Memorial Hospital-Linkou, Taoyuan 33305, Taiwan
- Correspondence: ; Tel.: +886-3-211-8800
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Kukreja AA, Kavuri S, Joglekar AP. Microtubule Attachment and Centromeric Tension Shape the Protein Architecture of the Human Kinetochore. Curr Biol 2020; 30:4869-4881.e5. [PMID: 33035484 DOI: 10.1016/j.cub.2020.09.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 07/23/2020] [Accepted: 09/14/2020] [Indexed: 12/18/2022]
Abstract
The nanoscale protein architecture of the kinetochore plays an integral role in specifying the mechanisms underlying its functions in chromosome segregation. However, defining this architecture in human cells remains challenging because of the large size and compositional complexity of the kinetochore. Here, we use Förster resonance energy transfer to reveal the architecture of individual kinetochore-microtubule attachments in human cells. We find that the microtubule-binding domains of the Ndc80 complex cluster at the microtubule plus end. This clustering occurs only after microtubule attachment, and it increases proportionally with centromeric tension. Surprisingly, Ndc80 complex clustering is independent of the organization and number of its centromeric receptors. Moreover, this clustering is similar in yeast and human kinetochores despite significant differences in their centromeric organizations. These and other data suggest that the microtubule-binding interface of the human kinetochore behaves like a flexible "lawn" despite being nucleated by repeating biochemical subunits.
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Affiliation(s)
- Alexander A Kukreja
- Department of Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109, USA
| | - Sisira Kavuri
- Department of Cellular & Developmental Biology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Ajit P Joglekar
- Department of Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109, USA; Department of Cellular & Developmental Biology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA.
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Ghodgaonkar-Steger M, Potocnjak M, Zimniak T, Fischböck-Halwachs J, Solis-Mezarino V, Singh S, Speljko T, Hagemann G, Drexler DJ, Witte G, Herzog F. C-Terminal Motifs of the MTW1 Complex Cooperatively Stabilize Outer Kinetochore Assembly in Budding Yeast. Cell Rep 2020; 32:108190. [PMID: 32997987 DOI: 10.1016/j.celrep.2020.108190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/18/2020] [Accepted: 09/01/2020] [Indexed: 12/01/2022] Open
Abstract
Kinetochores are macromolecular protein assemblies at centromeres that mediate accurate chromosome segregation during cell division. The outer kinetochore KNL1SPC105, MIS12MTW1, and NDC80NDC80 complexes assemble the KMN network, which harbors the sites of microtubule binding and spindle assembly checkpoint signaling. The buildup of the KMN network that transmits microtubule pulling forces to budding yeast point centromeres is poorly understood. Here, we identify 225 inter-protein crosslinks by mass spectrometry on KMN complexes isolated from Saccharomyces cerevisiae that delineate the KMN subunit connectivity for outer kinetochore assembly. C-Terminal motifs of Nsl1 and Mtw1 recruit the SPC105 complex through Kre28, and both motifs aid tethering of the NDC80 complex by the previously reported Dsn1 C terminus. We show that a hub of three C-terminal MTW1 subunit motifs mediates the cooperative stabilization of the KMN network, which is augmented by a direct NDC80-SPC105 association.
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Affiliation(s)
- Medini Ghodgaonkar-Steger
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Mia Potocnjak
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Tomasz Zimniak
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Josef Fischböck-Halwachs
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Victor Solis-Mezarino
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Sylvia Singh
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Tea Speljko
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Götz Hagemann
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - David Jan Drexler
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Gregor Witte
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Franz Herzog
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany.
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van der Laan S, Lévêque MF, Marcellin G, Vezenkov L, Lannay Y, Dubra G, Bompard G, Ovejero S, Urbach S, Burgess A, Amblard M, Sterkers Y, Bastien P, Rogowski K. Evolutionary Divergence of Enzymatic Mechanisms for Tubulin Detyrosination. Cell Rep 2020; 29:4159-4171.e6. [PMID: 31851940 DOI: 10.1016/j.celrep.2019.11.074] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/10/2019] [Accepted: 11/18/2019] [Indexed: 12/23/2022] Open
Abstract
The two related members of the vasohibin family, VASH1 and VASH2, encode human tubulin detyrosinases. Here we demonstrate that, in contrast to VASH1, which requires binding of small vasohibin binding protein (SVBP), VASH2 has autonomous tubulin detyrosinating activity. Moreover, we demonstrate that SVBP acts as a bona fide activator of both enzymes. Phylogenetic analysis of the vasohibin family revealed that regulatory diversification of VASH-mediated tubulin detyrosination coincided with early vertebrate evolution. Thus, as a model organism for functional analysis, we used Trypanosoma brucei (Tb), an evolutionarily early-branched eukaryote that possesses a single VASH and encodes a terminal tyrosine on both α- and β-tubulin tails, both subject to removal. Remarkably, although detyrosination levels are high in the flagellum, TbVASH knockout parasites did not present any noticeable flagellar abnormalities. In contrast, we observed reduced proliferation associated with profound morphological and mitotic defects, underscoring the importance of tubulin detyrosination in cell division.
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Affiliation(s)
- Siem van der Laan
- Tubulin Code Team, Institute of Human Genetics (IGH), CNRS-Université Montpellier, 141 rue de la Cardonille, 34293 Montpellier Cedex 5, France.
| | - Maude F Lévêque
- Université Montpellier-CNRS, "MiVEGEC," Faculté de Medicine and Centre Hospitalier Universitaire, 39 avenue Charles Flahault, 34295 Montpellier Cedex 5, France.
| | - Guillaume Marcellin
- Tubulin Code Team, Institute of Human Genetics (IGH), CNRS-Université Montpellier, 141 rue de la Cardonille, 34293 Montpellier Cedex 5, France
| | - Lubomir Vezenkov
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS-Université Montpellier-ENSCM, 34093 Montpellier Cedex 5, France
| | - Yoann Lannay
- Tubulin Code Team, Institute of Human Genetics (IGH), CNRS-Université Montpellier, 141 rue de la Cardonille, 34293 Montpellier Cedex 5, France
| | - Geronimo Dubra
- Tubulin Code Team, Institute of Human Genetics (IGH), CNRS-Université Montpellier, 141 rue de la Cardonille, 34293 Montpellier Cedex 5, France
| | - Guillaume Bompard
- Tubulin Code Team, Institute of Human Genetics (IGH), CNRS-Université Montpellier, 141 rue de la Cardonille, 34293 Montpellier Cedex 5, France
| | - Sara Ovejero
- Tubulin Code Team, Institute of Human Genetics (IGH), CNRS-Université Montpellier, 141 rue de la Cardonille, 34293 Montpellier Cedex 5, France
| | - Serge Urbach
- Functional Proteomics Platform (FPP), IGF, Université Montpellier, CNRS, INSERM, Montpellier, France
| | - Andrew Burgess
- ANZAC Research Institute, Gate 3 Hospital Rd., Concord, Sydney, NSW 2139, Australia; The University of Sydney Concord Clinical School, Faculty of Medicine and Health, Sydney, NSW, Australia
| | - Muriel Amblard
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS-Université Montpellier-ENSCM, 34093 Montpellier Cedex 5, France
| | - Yvon Sterkers
- Université Montpellier-CNRS, "MiVEGEC," Faculté de Medicine and Centre Hospitalier Universitaire, 39 avenue Charles Flahault, 34295 Montpellier Cedex 5, France
| | - Patrick Bastien
- Université Montpellier-CNRS, "MiVEGEC," Faculté de Medicine and Centre Hospitalier Universitaire, 39 avenue Charles Flahault, 34295 Montpellier Cedex 5, France
| | - Krzysztof Rogowski
- Tubulin Code Team, Institute of Human Genetics (IGH), CNRS-Université Montpellier, 141 rue de la Cardonille, 34293 Montpellier Cedex 5, France.
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75
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Tubulin modifying enzymes as target for the treatment oftau-related diseases. Pharmacol Ther 2020; 218:107681. [PMID: 32961263 DOI: 10.1016/j.pharmthera.2020.107681] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/09/2020] [Indexed: 01/17/2023]
Abstract
In the brain of patients with Alzheimer's disease (AD), the number and length of microtubules (MTs) are significantly and selectively reduced. MTs are involved in a wide range of cellular functions, and defects of the microtubular system have emerged as a unifying hypothesis for the heterogeneous and variable clinical presentations of AD. MTs orchestrate their numerous functions through the spatiotemporal regulation of the binding of specialised microtubule-associated proteins (MAPs) and molecular motors. Covalent posttranslational modifications (PTMs) on the tubulin C-termini that protrude at the surface of MTs regulate the binding of these effectors. In neurons, MAP tau is highly abundant and its abnormal dissociation from MTs in the axon, cellular mislocalization and hyperphosphorylation, are primary events leading to neuronal death. Consequently, compounds targeting tau phosphorylation or aggregation are currently evaluated but their clinical significance has not been demonstrated yet. In this review, we discuss the emerging link between tubulin PTMs and tau dysfunction. In neurons, high levels of glutamylation and detyrosination profoundly impact the physicochemical properties at the surface of MTs. Moreover, in patients with early-onset progressive neurodegeneration, deleterious mutations in enzymes involved in modifying MTs at the surface have recently been identified, underscoring the importance of this enzymatic machinery in neurology. We postulate that pharmacologically targeting the tubulin-modifying enzymes holds promise as therapeutic approach for the treatment of neurodegenerative diseases.
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76
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Liang C, Zhang Z, Chen Q, Yan H, Zhang M, Zhou L, Xu J, Lu W, Wang F. Centromere-localized Aurora B kinase is required for the fidelity of chromosome segregation. J Cell Biol 2020; 219:133535. [PMID: 31868888 PMCID: PMC7041694 DOI: 10.1083/jcb.201907092] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 11/14/2019] [Accepted: 11/18/2019] [Indexed: 12/23/2022] Open
Abstract
Aurora B kinase plays an essential role in chromosome bi-orientation, which is a prerequisite for equal segregation of chromosomes during mitosis. However, it remains largely unclear whether centromere-localized Aurora B is required for faithful chromosome segregation. Here we show that histone H3 Thr-3 phosphorylation (H3pT3) and H2A Thr-120 phosphorylation (H2ApT120) can independently recruit Aurora B. Disrupting H3pT3-mediated localization of Aurora B at the inner centromere impedes the decline in H2ApT120 during metaphase and causes H2ApT120-dependent accumulation of Aurora B at the kinetochore-proximal centromere. Consequently, silencing of the spindle assembly checkpoint (SAC) is delayed, whereas the fidelity of chromosome segregation is negligibly affected. Further eliminating an H2ApT120-dependent pool of Aurora B restores proper timing for SAC silencing but increases chromosome missegregation. Our data indicate that H2ApT120-mediated localization of Aurora B compensates for the loss of an H3pT3-dependent pool of Aurora B to correct improper kinetochore-microtubule attachments. This study provides important insights into how centromeric Aurora B regulates SAC and kinetochore attachment to microtubules to ensure error-free chromosome segregation.
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Affiliation(s)
- Cai Liang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhenlei Zhang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qinfu Chen
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Haiyan Yan
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Miao Zhang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Linli Zhou
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Junfen Xu
- Department of Gynecological Oncology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Weiguo Lu
- Department of Gynecological Oncology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Women's Reproductive Health Key Research Laboratory of Zhejiang Province, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Fangwei Wang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Gynecological Oncology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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77
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Audett MR, Maresca TJ. The whole is greater than the sum of its parts: at the intersection of order, disorder, and kinetochore function. Essays Biochem 2020; 64:349-358. [PMID: 32756877 PMCID: PMC8011995 DOI: 10.1042/ebc20190069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 11/17/2022]
Abstract
The kinetochore (KT) field has matured tremendously since Earnshaw first identified CENP-A, CENP-B, and CENP-C [1,2]. In the past 35 years, the accumulation of knowledge has included: defining the parts list, identifying epistatic networks of interdependence within the parts list, understanding the spatial organization of subcomplexes into a massive structure - hundreds of megadaltons in size, and dissecting the functions of the KT in its entirety as well as of its individual parts. Like nearly all cell and molecular biology fields, the structure-function paradigm has been foundational to advances in the KT field. A point nicely highlighted by the fact that we are at the precipice of the in vitro reconstitution of a functional KT holo complex. Yet conventional notions of structure cannot provide a complete picture of the KT especially since it contains an abundance of unstructured or intrinsically disordered constituents. The combination of structured and disordered proteins within the KT results in an assembled system that is functionally greater than the sum of its parts.
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Affiliation(s)
- Margaux R Audett
- Biology Department, University of Massachusetts, Amherst, MA, U.S.A
| | - Thomas J Maresca
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, U.S.A
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78
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Establishing correct kinetochore-microtubule attachments in mitosis and meiosis. Essays Biochem 2020; 64:277-287. [PMID: 32406497 DOI: 10.1042/ebc20190072] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/20/2020] [Accepted: 04/24/2020] [Indexed: 01/01/2023]
Abstract
Faithful chromosome segregation in mitosis and meiosis requires that chromosomes properly attach to spindle microtubules. Initial kinetochore-microtubule attachments are often incorrect and rely on error correction mechanisms to release improper attachments, allowing the formation of new attachments. Aurora B kinase and, in mammalian germ cells, Aurora C kinase function as the enzymatic component of the Chromosomal Passenger Complex (CPC), which localizes to the inner centromere/kinetochore and phosphorylates kinetochore proteins for microtubule release during error correction. In this review, we discuss recent findings of the molecular pathways that regulate the chromosomal localization of Aurora B and C kinases in human cell lines, mice, fission yeast, and budding yeast. We also discuss differences in the importance of localization pathways between mitosis and meiosis.
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79
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Microtubules pull the strings: disordered sequences as efficient couplers of microtubule-generated force. Essays Biochem 2020; 64:371-382. [PMID: 32502246 DOI: 10.1042/ebc20190078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/01/2020] [Accepted: 05/14/2020] [Indexed: 11/17/2022]
Abstract
Microtubules are dynamic polymers that grow and shrink through addition or loss of tubulin subunits at their ends. Microtubule ends generate mechanical force that moves chromosomes and cellular organelles, and provides mechanical tension. Recent literature describes a number of proteins and protein complexes that couple dynamics of microtubule ends to movements of their cellular cargoes. These 'couplers' are quite diverse in their microtubule-binding domains (MTBDs), while sharing similarity in function, but a systematic understanding of the principles underlying their activity is missing. Here, I review various types of microtubule couplers, focusing on their essential activities: ability to follow microtubule ends and capture microtubule-generated force. Most of the couplers require presence of unstructured positively charged sequences and multivalency in their microtubule-binding sites to efficiently convert the microtubule-generated force into useful connection to a cargo. An overview of the microtubule features supporting end-tracking and force-coupling, and the experimental methods to assess force-coupling properties is also provided.
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80
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Kinetochore-microtubule coupling mechanisms mediated by the Ska1 complex and Cdt1. Essays Biochem 2020; 64:337-347. [PMID: 32844209 DOI: 10.1042/ebc20190075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 11/17/2022]
Abstract
The faithful segregation of duplicated sister chromatids rely on the remarkable ability of kinetochores to sustain stable load bearing attachments with the dynamic plus ends of kinetochore-microtubules (kMTs). The outer layer of the kinetochore recruits several motor and non-motor microtubule-associated proteins (MAPs) that help the kinetochores establish and maintain a load bearing dynamic attachment with kMTs. The primary kMT-binding protein, the Ndc80 complex (Ndc80c), which is highly conserved among diverse organisms from yeast to humans, performs this essential function with assistance from other MAPs. These MAPs are not an integral part of the kinetochore, but they localize to the kinetochore periodically throughout mitosis and regulate the strength of the kinetochore microtubule attachments. Here, we attempt to summarize the recent advances that have been made toward furthering our understanding of this co-operation between the Ndc80c and these MAPs, focusing on the spindle and kinetochore-associated 1 (Ska1) complex (Ska1c) and Cdc10-dependent transcript 1 (Cdt1) in humans.
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81
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Welch R, Harris SA, Harlen OG, Read DJ. KOBRA: a fluctuating elastic rod model for slender biological macromolecules. SOFT MATTER 2020; 16:7544-7555. [PMID: 32706006 DOI: 10.1039/d0sm00491j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
KOBRA (KirchOff Biological Rod Algorithm) is an algorithm and software package designed to perform dynamical simulations of elongated biomolecules such as those containing alpha-helices and coiled-coils. It represents these as coarsely-discretised Kirchoff rods, with linear elements that can stretch, bend and twist independently. These rods can have anisotropic and inhomogeneous parameters and bent or twisted equilibrium structures, allowing for a coarse-grained parameterisation of complex biological structures. Each element is non-inertial and subject to thermal fluctuations. The speed and simplicity of the algorithm allows KOBRA rods to easily access timescales from nanoseconds to seconds. To demonstrate this functionality, a KOBRA rod was parameterised using data from all-atom simulations of the Ndc80 protein complex, and compared against these simulations and negative-stain EM images. The distribution of bend angles and principal components were highly correlated between KOBRA, all-atom molecular dynamics, and experimental data. The properties of a hinge region, thought to be found at an unstructured loop, were studied. A C++ implementation of KOBRA is available under the GNU GPLv3 free software licence.
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Affiliation(s)
- Robert Welch
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Sarah A Harris
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Oliver G Harlen
- School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK.
| | - Daniel J Read
- School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK.
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82
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Hara M, Fukagawa T. Dynamics of kinetochore structure and its regulations during mitotic progression. Cell Mol Life Sci 2020; 77:2981-2995. [PMID: 32052088 PMCID: PMC11104943 DOI: 10.1007/s00018-020-03472-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 12/27/2019] [Accepted: 01/28/2020] [Indexed: 12/12/2022]
Abstract
Faithful chromosome segregation during mitosis in eukaryotes requires attachment of the kinetochore, a large protein complex assembled on the centromere of each chromosome, to the spindle microtubules. The kinetochore is a structural interface for the microtubule attachment and provides molecular surveillance mechanisms that monitor and ensure the precise microtubule attachment as well, including error correction and spindle assembly checkpoint. During mitotic progression, the kinetochore undergoes dynamic morphological changes that are observable through electron microscopy as well as through fluorescence microscopy. These structural changes might be associated with the kinetochore function. In this review, we summarize how the dynamics of kinetochore morphology are associated with its functions and discuss recent findings on the switching of protein interaction networks in the kinetochore during cell cycle progression.
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Affiliation(s)
- Masatoshi Hara
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
| | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
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83
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Benzi G, Piatti S. Killing two birds with one stone: how budding yeast Mps1 controls chromosome segregation and spindle assembly checkpoint through phosphorylation of a single kinetochore protein. Curr Genet 2020; 66:1037-1044. [PMID: 32632756 DOI: 10.1007/s00294-020-01091-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 12/11/2022]
Abstract
During mitosis, the identical sister chromatids of each chromosome must attach through their kinetochores to microtubules emanating from opposite spindle poles. This process, referred to as chromosome biorientation, is essential for equal partitioning of the genetic information to the two daughter cells. Defects in chromosome biorientation can give rise to aneuploidy, a hallmark of cancer and genetic diseases. A conserved surveillance mechanism called spindle assembly checkpoint (SAC) prevents the onset of anaphase until biorientation is attained. Key to chromosome biorientation is an error correction mechanism that allows kinetochores to establish proper bipolar attachments by disengaging faulty kinetochore-microtubule connections. Error correction relies on the Aurora B and Mps1 kinases that also promote SAC signaling, raising the possibility that they are part of a single sensory device responding to improper attachments and concomitantly controlling both their disengagement and a temporary mitotic arrest. In budding yeast, Aurora B and Mps1 promote error correction independently from one another, but while the substrates of Aurora B in this process are at least partially known, the mechanism underlying the involvement of Mps1 in the error correction pathway is unknown. Through the characterization of a novel mps1 mutant and an unbiased genetic screen for extragenic suppressors, we recently gained evidence that a common mechanism based on Mps1-dependent phosphorylation of the Knl1/Spc105 kinetochore scaffold and subsequent recruitment of the Bub1 kinase is critical for the function of Mps1 in chromosome biorientation as well as for SAC activation (Benzi et al. EMBO Rep, 2020).
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Affiliation(s)
- Giorgia Benzi
- CRBM, University of Montpellier, CNRS, 1919 Route de Mende, 34293, Montpellier, France
| | - Simonetta Piatti
- CRBM, University of Montpellier, CNRS, 1919 Route de Mende, 34293, Montpellier, France.
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84
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Wimbish RT, DeLuca KF, Mick JE, Himes J, Jiménez-Sánchez I, Jeyaprakash AA, DeLuca JG. The Hec1/Ndc80 tail domain is required for force generation at kinetochores, but is dispensable for kinetochore-microtubule attachment formation and Ska complex recruitment. Mol Biol Cell 2020; 31:1453-1473. [PMID: 32401635 PMCID: PMC7359571 DOI: 10.1091/mbc.e20-05-0286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/08/2020] [Indexed: 12/19/2022] Open
Abstract
The conserved kinetochore-associated NDC80 complex (composed of Hec1/Ndc80, Nuf2, Spc24, and Spc25) has well-documented roles in mitosis including 1) connecting mitotic chromosomes to spindle microtubules to establish force-transducing kinetochore-microtubule attachments and 2) regulating the binding strength between kinetochores and microtubules such that correct attachments are stabilized and erroneous attachments are released. Although the NDC80 complex plays a central role in forming and regulating attachments to microtubules, additional factors support these processes as well, including the spindle and kinetochore-associated (Ska) complex. Multiple lines of evidence suggest that Ska complexes strengthen attachments by increasing the ability of NDC80 complexes to bind microtubules, especially to depolymerizing microtubule plus ends, but how this is accomplished remains unclear. Using cell-based and in vitro assays, we demonstrate that the Hec1 tail domain is dispensable for Ska complex recruitment to kinetochores and for generation of kinetochore-microtubule attachments in human cells. We further demonstrate that Hec1 tail phosphorylation regulates kinetochore-microtubule attachment stability independently of the Ska complex. Finally, we map the location of the Ska complex in cells to a region near the coiled-coil domain of the NDC80 complex and demonstrate that this region is required for Ska complex recruitment to the NDC80 complex--microtubule interface.
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Affiliation(s)
- Robert T. Wimbish
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Keith F. DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Jeanne E. Mick
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Jack Himes
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | | | | | - Jennifer G. DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
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85
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Barbosa J, Conde C, Sunkel C. RZZ-SPINDLY-DYNEIN: you got to keep 'em separated. Cell Cycle 2020; 19:1716-1726. [PMID: 32544383 PMCID: PMC7469663 DOI: 10.1080/15384101.2020.1780382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 10/24/2022] Open
Abstract
To maintain genome stability, chromosomes must be equally distributed among daughter cells at the end of mitosis. The accuracy of chromosome segregation requires sister-kinetochores to stably attach to microtubules emanating from opposite spindle poles. However, initial kinetochore-microtubule interactions are able to turnover so that defective attachment configurations that typically arise during early mitosis may be corrected. Growing evidence supports a role for the RZZ complex in preventing the stabilization of erroneous kinetochore-microtubule attachments. This inhibitory function of RZZ toward end-on attachments is relieved by DYNEIN-mediated transport of the complex as chromosomes congress and appropriate interactions with microtubules are established. However, it remains unclear how DYNEIN is antagonized to prevent premature RZZ removal. We recently described a new mechanism that sheds new light on this matter. We found that POLO kinase phosphorylates the DYNEIN adaptor SPINDLY to promote the uncoupling between RZZ and DYNEIN. Elevated POLO activity during prometaphase ensures that RZZ is retained at kinetochores to allow the dynamic turnover of kinetochore-microtubule interactions and prevent the stabilization of erroneous attachments. Here, we discuss additional interpretations to explain a model for POLO-dependent regulation of the RZZ-SPINDLY-DYNEIN module during mitosis.
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Affiliation(s)
- João Barbosa
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
| | - Carlos Conde
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
| | - Claudio Sunkel
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
- ICBAS - Instituto de Ciência Biomédicas Abel Salazar da Universidade do Porto, Porto, Portugal
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86
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Ustinov NB, Korshunova AV, Gudimchuk NB. Protein Complex NDC80: Properties, Functions, and Possible Role in Pathophysiology of Cell Division. BIOCHEMISTRY (MOSCOW) 2020; 85:448-462. [PMID: 32569552 DOI: 10.1134/s0006297920040057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mitotic division maintains genetic identity of any multicellular organism throughout an entire lifetime. Each time a parent cell divides, chromosomes are equally distributed between the daughter cells due to the action of mitotic spindle. Mitotic spindle is formed by the microtubules that represent dynamic polymers of tubulin protein. Spindle microtubules are attached end-on to kinetochores - large multi-protein complexes on chromosomes. This review focuses on the four-subunit NDC80 complex, one of the most important kinetochore elements that plays a major role in the attachment of assembling/disassembling microtubule ends to the chromosomes. Here, we summarize published data on the structure, properties, and regulation of the NDC80 complex and discuss possible relationship between changes in the expression of genes coding for the NDC80 complex components, mitotic disorders, and oncogenesis with special emphasis on the diagnostic and therapeutic potential of NDC80.
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Affiliation(s)
- N B Ustinov
- Center for Theoretical Problems of Physico-Chemical Pharmacology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - A V Korshunova
- Center for Theoretical Problems of Physico-Chemical Pharmacology, Russian Academy of Sciences, Moscow, 119991, Russia.,Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia
| | - N B Gudimchuk
- Center for Theoretical Problems of Physico-Chemical Pharmacology, Russian Academy of Sciences, Moscow, 119991, Russia. .,Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia
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87
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Kixmoeller K, Allu PK, Black BE. The centromere comes into focus: from CENP-A nucleosomes to kinetochore connections with the spindle. Open Biol 2020; 10:200051. [PMID: 32516549 PMCID: PMC7333888 DOI: 10.1098/rsob.200051] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Eukaryotic chromosome segregation relies upon specific connections from DNA to the microtubule-based spindle that forms at cell division. The chromosomal locus that directs this process is the centromere, where a structure called the kinetochore forms upon entry into mitosis. Recent crystallography and single-particle electron microscopy have provided unprecedented high-resolution views of the molecular complexes involved in this process. The centromere is epigenetically specified by nucleosomes harbouring a histone H3 variant, CENP-A, and we review recent progress on how it differentiates centromeric chromatin from the rest of the chromosome, the biochemical pathway that mediates its assembly and how two non-histone components of the centromere specifically recognize CENP-A nucleosomes. The core centromeric nucleosome complex (CCNC) is required to recruit a 16-subunit complex termed the constitutive centromere associated network (CCAN), and we highlight recent structures reported of the budding yeast CCAN. Finally, the structures of multiple modular sub-complexes of the kinetochore have been solved at near-atomic resolution, providing insight into how connections are made to the CCAN on one end and to the spindle microtubules on the other. One can now build molecular models from the DNA through to the physical connections to microtubules.
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Affiliation(s)
- Kathryn Kixmoeller
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Praveen Kumar Allu
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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88
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Killinger K, Böhm M, Steinbach P, Hagemann G, Blüggel M, Jänen K, Hohoff S, Bayer P, Herzog F, Westermann S. Auto-inhibition of Mif2/CENP-C ensures centromere-dependent kinetochore assembly in budding yeast. EMBO J 2020; 39:e102938. [PMID: 32515113 PMCID: PMC7360964 DOI: 10.15252/embj.2019102938] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 04/27/2020] [Accepted: 05/12/2020] [Indexed: 11/28/2022] Open
Abstract
Kinetochores are chromatin‐bound multi‐protein complexes that allow high‐fidelity chromosome segregation during mitosis and meiosis. Kinetochore assembly is exclusively initiated at chromatin containing Cse4/CENP‐A nucleosomes. The molecular mechanisms ensuring that subcomplexes assemble efficiently into kinetochores only at centromeres, but not anywhere else, are incompletely understood. Here, we combine biochemical and genetic experiments to demonstrate that auto‐inhibition of the conserved kinetochore subunit Mif2/CENP‐C contributes to preventing unscheduled kinetochore assembly in budding yeast cells. We show that wild‐type Mif2 is attenuated in its ability to bind a key downstream component in the assembly pathway, the Mtw1 complex, and that addition of Cse4 nucleosomes overcomes this inhibition. By exchanging the N‐terminus of Mif2 with its functional counterpart from Ame1/CENP‐U, we have created a Mif2 mutant which bypasses the Cse4 requirement for Mtw1 binding in vitro, thereby shortcutting kinetochore assembly. Expression of this Mif2 mutant in cells leads to mis‐localization of the Mtw1 complex and causes pronounced chromosome segregation defects. We propose that auto‐inhibition of Mif2/CENP‐C constitutes a key concept underlying the molecular logic of kinetochore assembly.
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Affiliation(s)
- Kerstin Killinger
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Miriam Böhm
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Philine Steinbach
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Götz Hagemann
- Department of Biochemistry, Gene Center, Ludwig-Maximilians-Universität München, München, Germany
| | - Mike Blüggel
- Structural and Medicinal Biochemistry, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Karolin Jänen
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Simone Hohoff
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Peter Bayer
- Structural and Medicinal Biochemistry, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Franz Herzog
- Department of Biochemistry, Gene Center, Ludwig-Maximilians-Universität München, München, Germany
| | - Stefan Westermann
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
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89
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Prc1-rich kinetochores are required for error-free acentrosomal spindle bipolarization during meiosis I in mouse oocytes. Nat Commun 2020; 11:2652. [PMID: 32461611 PMCID: PMC7253481 DOI: 10.1038/s41467-020-16488-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 05/01/2020] [Indexed: 12/18/2022] Open
Abstract
Acentrosomal meiosis in oocytes represents a gametogenic challenge, requiring spindle bipolarization without predefined bipolar cues. While much is known about the structures that promote acentrosomal microtubule nucleation, less is known about the structures that mediate spindle bipolarization in mammalian oocytes. Here, we show that in mouse oocytes, kinetochores are required for spindle bipolarization in meiosis I. This process is promoted by oocyte-specific, microtubule-independent enrichment of the antiparallel microtubule crosslinker Prc1 at kinetochores via the Ndc80 complex. In contrast, in meiosis II, cytoplasm that contains upregulated factors including Prc1 supports kinetochore-independent pathways for spindle bipolarization. The kinetochore-dependent mode of spindle bipolarization is required for meiosis I to prevent chromosome segregation errors. Human oocytes, where spindle bipolarization is reportedly error prone, exhibit no detectable kinetochore enrichment of Prc1. This study reveals an oocyte-specific function of kinetochores in acentrosomal spindle bipolarization in mice, and provides insights into the error-prone nature of human oocytes. Oocyte meiosis must achieve spindle bipolarization without predefined spatial cues. Yoshida et al. demonstrate that spindle bipolarization during meiosis I in mouse oocytes requires kinetochores to prevent chromosome segregation errors, a phenomenon that does not occur in error-prone human oocytes.
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90
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Roscioli E, Germanova TE, Smith CA, Embacher PA, Erent M, Thompson AI, Burroughs NJ, McAinsh AD. Ensemble-Level Organization of Human Kinetochores and Evidence for Distinct Tension and Attachment Sensors. Cell Rep 2020; 31:107535. [PMID: 32348762 PMCID: PMC7196887 DOI: 10.1016/j.celrep.2020.107535] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 02/10/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022] Open
Abstract
Kinetochores are multi-protein machines that form dynamic attachments to microtubules and control chromosome segregation. High fidelity is ensured because kinetochores can monitor attachment status and tension, using this information to activate checkpoints and error-correction mechanisms. To explore how kinetochores achieve this, we used two- and three-color subpixel fluorescence localization to define how proteins from six major complexes (CCAN, MIS12, NDC80, KNL1, RZZ, and SKA) and the checkpoint proteins Bub1, Mad1, and Mad2 are organized in the human kinetochore. This reveals how the outer kinetochore has a high nematic order and is largely invariant to the loss of attachment or tension, except for two mechanical sensors. First, Knl1 unravels to relay tension, and second, NDC80 undergoes jackknifing and loss of nematic order under microtubule detachment, with only the latter wired up to the checkpoint signaling system. This provides insight into how kinetochores integrate mechanical signals to promote error-free chromosome segregation.
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Affiliation(s)
- Emanuele Roscioli
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Tsvetelina E Germanova
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Christopher A Smith
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Peter A Embacher
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Mathematics Institute, University of Warwick, Coventry, UK
| | - Muriel Erent
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Amelia I Thompson
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Nigel J Burroughs
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Mathematics Institute, University of Warwick, Coventry, UK.
| | - Andrew D McAinsh
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK; Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK.
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91
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Pachis ST, Hiruma Y, Tromer EC, Perrakis A, Kops GJPL. Interactions between N-terminal Modules in MPS1 Enable Spindle Checkpoint Silencing. Cell Rep 2020; 26:2101-2112.e6. [PMID: 30784592 DOI: 10.1016/j.celrep.2019.01.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/13/2018] [Accepted: 01/04/2019] [Indexed: 10/27/2022] Open
Abstract
Faithful chromosome segregation relies on the ability of the spindle assembly checkpoint (SAC) to delay anaphase onset until chromosomes are attached to the mitotic spindle via their kinetochores. MPS1 kinase is recruited to kinetochores to initiate SAC signaling and is removed from kinetochores once stable microtubule attachments have been formed to allow normal mitotic progression. Here, we show that a helical fragment within the kinetochore-targeting N-terminal extension (NTE) module of MPS1 is required for interactions with kinetochores and forms intramolecular interactions with its adjacent tetratricopeptide repeat (TPR) domain. Bypassing this NTE-TPR interaction results in high MPS1 levels at kinetochores due to loss of regulatory input into MPS1 localization, inefficient MPS1 delocalization upon microtubule attachment, and SAC silencing defects. These results show that SAC responsiveness to attachments relies on regulated intramolecular interactions in MPS1 and highlight the sensitivity of mitosis to perturbations in the dynamics of the MPS1-NDC80-C interactions.
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Affiliation(s)
- Spyridon T Pachis
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, 3584 CT, the Netherlands
| | - Yoshitaka Hiruma
- Department of Biochemistry, the Netherlands Cancer Institute, Amsterdam, 1066 CX, the Netherlands
| | - Eelco C Tromer
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Anastassis Perrakis
- Department of Biochemistry, the Netherlands Cancer Institute, Amsterdam, 1066 CX, the Netherlands
| | - Geert J P L Kops
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, 3584 CT, the Netherlands.
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92
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Curtis NL, Ruda GF, Brennan P, Bolanos-Garcia VM. Deregulation of Chromosome Segregation and Cancer. ANNUAL REVIEW OF CANCER BIOLOGY 2020. [DOI: 10.1146/annurev-cancerbio-030419-033541] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The mitotic spindle assembly checkpoint (SAC) is an intricate cell signaling system that ensures the high fidelity and timely segregation of chromosomes during cell division. Mistakes in this process can lead to the loss, gain, or rearrangement of the genetic material. Gross chromosomal aberrations are usually lethal but can cause birth and development defects as well as cancer. Despite advances in the identification of SAC protein components, important details of the interactions underpinning chromosome segregation regulation remain to be established. This review discusses the current understanding of the function, structure, mode of regulation, and dynamics of the assembly and disassembly of SAC subcomplexes, which ultimately safeguard the accurate transmission of a stable genome to descendants. We also discuss how diverse oncoviruses take control of human cell division by exploiting the SAC and the potential of this signaling circuitry as a pool of drug targets to develop effective cancer therapies.
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Affiliation(s)
- Natalie L. Curtis
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Gian Filippo Ruda
- Target Discovery Institute and Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Paul Brennan
- Target Discovery Institute and Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Victor M. Bolanos-Garcia
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
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93
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Wimbish RT, DeLuca JG. Hec1/Ndc80 Tail Domain Function at the Kinetochore-Microtubule Interface. Front Cell Dev Biol 2020; 8:43. [PMID: 32161753 PMCID: PMC7054225 DOI: 10.3389/fcell.2020.00043] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/17/2020] [Indexed: 12/28/2022] Open
Abstract
Successful mitotic cell division is critically dependent on the formation of correct attachments between chromosomes and spindle microtubules. Microtubule attachments are mediated by kinetochores, which are large proteinaceous structures assembled on centromeric chromatin of mitotic chromosomes. These attachments must be sufficiently stable to transduce force; however, the strength of these attachments are also tightly regulated to ensure timely, error-free progression through mitosis. The highly conserved, kinetochore-associated NDC80 complex is a core component of the kinetochore-microtubule attachment machinery in eukaryotic cells. A small, disordered region within the Hec1 subunit of the NDC80 complex – the N-terminal “tail” domain – has been actively investigated during the last decade due to its roles in generating and regulating kinetochore-microtubule attachments. In this review, we discuss the role of the NDC80 complex, and specifically the Hec1 tail domain, at the kinetochore-microtubule interface, and how recent studies provide a more unified view of Hec1 tail domain function.
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Affiliation(s)
- Robert T Wimbish
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, United States
| | - Jennifer G DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, United States
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94
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Huis In 't Veld PJ, Volkov VA, Stender ID, Musacchio A, Dogterom M. Molecular determinants of the Ska-Ndc80 interaction and their influence on microtubule tracking and force-coupling. eLife 2019; 8:49539. [PMID: 31804178 PMCID: PMC6927755 DOI: 10.7554/elife.49539] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022] Open
Abstract
Errorless chromosome segregation requires load-bearing attachments of the plus ends of spindle microtubules to chromosome structures named kinetochores. How these end-on kinetochore attachments are established following initial lateral contacts with the microtubule lattice is poorly understood. Two microtubule-binding complexes, the Ndc80 and Ska complexes, are important for efficient end-on coupling and may function as a unit in this process, but precise conditions for their interaction are unknown. Here, we report that the Ska-Ndc80 interaction is phosphorylation-dependent and does not require microtubules, applied force, or several previously identified functional determinants including the Ndc80-loop and the Ndc80-tail. Both the Ndc80-tail, which we reveal to be essential for microtubule end-tracking, and Ndc80-bound Ska stabilize microtubule ends in a stalled conformation. Modulation of force-coupling efficiency demonstrates that the duration of stalled microtubule disassembly predicts whether a microtubule is stabilized and rescued by the kinetochore, likely reflecting a structural transition of the microtubule end.
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Affiliation(s)
- Pim J Huis In 't Veld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Vladimir A Volkov
- Department of Bionanoscience, Faculty of Applied Sciences, Delft University of Technology, Delft, Netherlands
| | - Isabelle D Stender
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.,Centre for Medical Biotechnology, Faculty of Biology, University Duisburg, Essen, Germany
| | - Marileen Dogterom
- Department of Bionanoscience, Faculty of Applied Sciences, Delft University of Technology, Delft, Netherlands
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95
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Hou Y, Wang Z, Huang S, Sun C, Zhao J, Shi J, Li Z, Wang Z, He X, Tam NL, Wu L. SKA3 Promotes tumor growth by regulating CDK2/P53 phosphorylation in hepatocellular carcinoma. Cell Death Dis 2019; 10:929. [PMID: 31804459 PMCID: PMC6895034 DOI: 10.1038/s41419-019-2163-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 01/20/2023]
Abstract
Spindle and kinetochore-related complex subunit 3 (SKA3) is a component of the spindle and kinetochore-related complexes and is essential for accurate timing of late mitosis. However, the relationship between SKA3 and hepatocellular carcinoma (HCC) has not yet been fully elucidated. Gene expression omnibus (GEO) (GSE62232, GSE45436, GSE6764, and GSE36376) and The Cancer Atlas (TCGA) datasets were analyzed to identify differential expression genes. Cell proliferation ability was analyzed using Cell Counting Kit-8 (CCK8) assay and plate clone formation assay, while scratch wound healing assay and transwell assay were used to analyze cell invasion. The role of SKA3 in vivo was explored using subcutaneous xenotransplantation model and lung metastasis model. Bioinformatics analysis found that hepatocellular carcinoma patients with high levels of expression of SKA3 have a poor prognosis. Similarly, immunohistochemical staining of 236 samples of tumors also found higher SKA3 expression in them, than in adjacent normal liver tissues. Significant levels of inhibition of in vivo and in vitro tumor proliferation and invasion result from the downregulation of SKA3. Mechanistically, SKA3 was found to affect tumor progression through the cell cycle and P53 signaling pathway as shown by the gene enrichment analysis (GSEA). G2/M phase arrest and severe apoptosis was also found to result from SKA3 knockdown, as shown by the inhibition of CDK2/p53 phosphorylation together with downregulation of BAX/Bcl-2 expression in HCC cells. Overall, these findings uncover the role of SKA3 in regulating the apoptosis and proliferation of hepatocellular carcinoma cells. This study was able to uncover new information on the tumorigenesis mechanism in hepatocellular carcinoma.
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Affiliation(s)
- Yuchen Hou
- Department of Organ Transplantation, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China.,Department of Liver Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 1630 Dongfang Road, Shanghai, 200127, China
| | - Ziming Wang
- Department of Biliary and Pancreatic Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Shanzhou Huang
- Department of Organ Transplantation, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China.,Department of General Surgery, Guangdong Provincial People's Hospital. Guangdong Academy of Medical Sciences, Guangzhou, 510030, China
| | - Chengjun Sun
- Department of Organ Transplantation, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Jingya Zhao
- The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Jiayu Shi
- The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Zhongqiu Li
- Department of Organ Transplantation, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Zekang Wang
- Department of Organ Transplantation, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Xiaoshun He
- Department of Organ Transplantation, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China. .,Guangdong Provincial Key Laboratory of Organ Donation and Transplant Immunology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China. .,Guangdong Provincial International Cooperation Base of Science and Technology (Organ Transplantation), The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Nga Lei Tam
- Digestive Medical Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China.
| | - Linwei Wu
- Department of Organ Transplantation, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China. .,Guangdong Provincial Key Laboratory of Organ Donation and Transplant Immunology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China. .,Guangdong Provincial International Cooperation Base of Science and Technology (Organ Transplantation), The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
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96
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Lawrimore J, Doshi A, Walker B, Bloom K. AI-Assisted Forward Modeling of Biological Structures. Front Cell Dev Biol 2019; 7:279. [PMID: 31799251 PMCID: PMC6868055 DOI: 10.3389/fcell.2019.00279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 10/30/2019] [Indexed: 01/01/2023] Open
Abstract
The rise of machine learning and deep learning technologies have allowed researchers to automate image classification. We describe a method that incorporates automated image classification and principal component analysis to evaluate computational models of biological structures. We use a computational model of the kinetochore to demonstrate our artificial-intelligence (AI)-assisted modeling method. The kinetochore is a large protein complex that connects chromosomes to the mitotic spindle to facilitate proper cell division. The kinetochore can be divided into two regions: the inner kinetochore, including proteins that interact with DNA; and the outer kinetochore, comprised of microtubule-binding proteins. These two kinetochore regions have been shown to have different distributions during metaphase in live budding yeast and therefore act as a test case for our forward modeling technique. We find that a simple convolutional neural net (CNN) can correctly classify fluorescent images of inner and outer kinetochore proteins and show a CNN trained on simulated, fluorescent images can detect difference in experimental images. A polymer model of the ribosomal DNA locus serves as a second test for the method. The nucleolus surrounds the ribosomal DNA locus and appears amorphous in live-cell, fluorescent microscopy experiments in budding yeast, making detection of morphological changes challenging. We show a simple CNN can detect subtle differences in simulated images of the ribosomal DNA locus, demonstrating our CNN-based classification technique can be used on a variety of biological structures.
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Affiliation(s)
- Josh Lawrimore
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Ayush Doshi
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Benjamin Walker
- Department of Mathematics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kerry Bloom
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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97
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Kuhn J, Dumont S. Mammalian kinetochores count attached microtubules in a sensitive and switch-like manner. J Cell Biol 2019; 218:3583-3596. [PMID: 31492713 PMCID: PMC6829666 DOI: 10.1083/jcb.201902105] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 07/10/2019] [Accepted: 08/08/2019] [Indexed: 01/09/2023] Open
Abstract
Kinetochores monitor their attachment to spindle microtubules to control spindle assembly checkpoint (SAC) signaling and cell cycle progression. Kuhn and Dumont show that individual mammalian kinetochores monitor the number of attached microtubules as a single unit in a sensitive and switch-like manner. The spindle assembly checkpoint (SAC) prevents anaphase until all kinetochores attach to the spindle. Each mammalian kinetochore binds many microtubules, but how many attached microtubules are required to turn off the checkpoint, and how the kinetochore monitors microtubule numbers, are not known and are central to understanding SAC mechanisms and function. To address these questions, here we systematically tune and fix the fraction of Hec1 molecules capable of microtubule binding. We show that Hec1 molecules independently bind microtubules within single kinetochores, but that the kinetochore does not independently process attachment information from different molecules. Few attached microtubules (20% occupancy) can trigger complete Mad1 loss, and Mad1 loss is slower in this case. Finally, we show using laser ablation that individual kinetochores detect changes in microtubule binding, not in spindle forces that accompany attachment. Thus, the mammalian kinetochore responds specifically to the binding of each microtubule and counts microtubules as a single unit in a sensitive and switch-like manner. This may allow kinetochores to rapidly react to early attachments and maintain a robust SAC response despite dynamic microtubule numbers.
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Affiliation(s)
- Jonathan Kuhn
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA .,Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA
| | - Sophie Dumont
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA .,Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA.,Department of Cell and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA
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98
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Amin MA, Agarwal S, Varma D. Mapping the kinetochore MAP functions required for stabilizing microtubule attachments to chromosomes during metaphase. Cytoskeleton (Hoboken) 2019; 76:398-412. [PMID: 31454167 DOI: 10.1002/cm.21559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 08/07/2019] [Accepted: 08/22/2019] [Indexed: 12/24/2022]
Abstract
In mitosis, faithful chromosome segregation is orchestrated by the dynamic interactions between the spindle microtubules (MTs) emanating from the opposite poles and the kinetochores of the chromosomes. However, the precise mechanism that coordinates the coupling of the kinetochore components to dynamic MTs has been a long-standing question. Microtubule-associated proteins (MAPs) regulate MT nucleation and dynamics, MT-mediated transport and MT cross-linking in cells. During mitosis, MAPs play an essential role not only in determining spindle length, position, and orientation but also in facilitating robust kinetochore-microtubule (kMT) attachments by linking the kinetochores to spindle MTs efficiently. The stability of MTs imparted by the MAPs is critical to ensure accurate chromosome segregation. This review primarily focuses on the specific function of nonmotor kinetochore MAPs, their recruitment to kinetochores and their MT-binding properties. We also attempt to synthesize and strengthen our understanding of how these MAPs work in coordination with the kinetochore-bound Ndc80 complex (the key component at the MT-binding interface in metaphase and anaphase) to establish stable kMT attachments and control accurate chromosome segregation during mitosis.
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Affiliation(s)
- Mohammed A Amin
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Shivangi Agarwal
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Dileep Varma
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Zhou Q, Lee KJ, Kurasawa Y, Hu H, An T, Li Z. Faithful chromosome segregation in Trypanosoma brucei requires a cohort of divergent spindle-associated proteins with distinct functions. Nucleic Acids Res 2019; 46:8216-8231. [PMID: 29931198 PMCID: PMC6144804 DOI: 10.1093/nar/gky557] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/07/2018] [Indexed: 12/29/2022] Open
Abstract
Faithful chromosome segregation depends on correct spindle microtubule-kinetochore attachment and requires certain spindle-associated proteins (SAPs) involved in regulating spindle dynamics and chromosome segregation. Little is known about the spindle-associated proteome in the early divergent Trypanosoma brucei and its roles in chromosome segregation. Here we report the identification of a cohort of divergent SAPs through localization-based screening and proximity-dependent biotin identification. We identified seven new SAPs and seventeen new nucleolar proteins that associate with the spindle, and demonstrated that the kinetochore protein KKIP4 also associates with the spindle. These SAPs localize to distinct subdomains of the spindle during mitosis, and all but one localize to nucleus during interphase and post-mitotic phases. Functional analyses of three nucleus- and spindle-associated proteins (NuSAPs) revealed distinct functions in chromosome segregation. NuSAP1 is a kinetoplastid-specific protein required for equal chromosome segregation and for maintaining the stability of the kinetochore proteins KKIP1 and KKT1. NuSAP2 is a highly divergent ASE1/PRC1/MAP65 homolog playing an essential role in promoting the G2/M transition. NuSAP3 is a kinetoplastid-specific Kif13-1-binding protein maintaining Kif13-1 protein stability and regulating the G2/M transition. Together, our work suggests that chromosome segregation in T. brucei requires a cohort of kinetoplastid-specific and divergent SAPs with distinct functions.
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Affiliation(s)
- Qing Zhou
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, TX 77030, USA
| | - Kyu Joon Lee
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, TX 77030, USA
| | - Yasuhiro Kurasawa
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, TX 77030, USA
| | - Huiqing Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, TX 77030, USA
| | - Tai An
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, TX 77030, USA
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, TX 77030, USA
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100
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Mallam AL, Marcotte EM. Systems-wide Studies Uncover Commander, a Multiprotein Complex Essential to Human Development. Cell Syst 2019; 4:483-494. [PMID: 28544880 DOI: 10.1016/j.cels.2017.04.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/25/2017] [Accepted: 03/23/2017] [Indexed: 11/27/2022]
Abstract
Recent mass spectrometry maps of the human interactome independently support the existence of a large multiprotein complex, dubbed "Commander." Broadly conserved across animals and ubiquitously expressed in nearly every human cell type examined thus far, Commander likely plays a fundamental cellular function, akin to other ubiquitous machines involved in expression, proteostasis, and trafficking. Experiments on individual subunits support roles in endosomal protein sorting, including the trafficking of Notch proteins, copper transporters, and lipoprotein receptors. Commander is critical for vertebrate embryogenesis, and defects in the complex and its interaction partners disrupt craniofacial, brain, and heart development. Here, we review the synergy between large-scale proteomic efforts and focused studies in the discovery of Commander, describe its composition, structure, and function, and discuss how it illustrates the power of systems biology. Based on 3D modeling and biochemical data, we draw strong parallels between Commander and the retromer cargo-recognition complex, laying a foundation for future research into Commander's role in human developmental disorders.
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Affiliation(s)
- Anna L Mallam
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA.
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA.
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