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The unconventional kinetoplastid kinetochore: from discovery toward functional understanding. Biochem Soc Trans 2017; 44:1201-1217. [PMID: 27911702 PMCID: PMC5095916 DOI: 10.1042/bst20160112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/15/2016] [Accepted: 06/21/2016] [Indexed: 11/17/2022]
Abstract
The kinetochore is the macromolecular protein complex that drives chromosome segregation in eukaryotes. Its most fundamental function is to connect centromeric DNA to dynamic spindle microtubules. Studies in popular model eukaryotes have shown that centromere protein (CENP)-A is critical for DNA-binding, whereas the Ndc80 complex is essential for microtubule-binding. Given their conservation in diverse eukaryotes, it was widely believed that all eukaryotes would utilize these components to make up a core of the kinetochore. However, a recent study identified an unconventional type of kinetochore in evolutionarily distant kinetoplastid species, showing that chromosome segregation can be achieved using a distinct set of proteins. Here, I review the discovery of the two kinetochore systems and discuss how their studies contribute to a better understanding of the eukaryotic chromosome segregation machinery.
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52
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van Hooff JJ, Tromer E, van Wijk LM, Snel B, Kops GJ. Evolutionary dynamics of the kinetochore network in eukaryotes as revealed by comparative genomics. EMBO Rep 2017. [PMID: 28642229 PMCID: PMC5579357 DOI: 10.15252/embr.201744102] [Citation(s) in RCA: 153] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
During eukaryotic cell division, the sister chromatids of duplicated chromosomes are pulled apart by microtubules, which connect via kinetochores. The kinetochore is a multiprotein structure that links centromeres to microtubules, and that emits molecular signals in order to safeguard the equal distribution of duplicated chromosomes over daughter cells. Although microtubule‐mediated chromosome segregation is evolutionary conserved, kinetochore compositions seem to have diverged. To systematically inventory kinetochore diversity and to reconstruct its evolution, we determined orthologs of 70 kinetochore proteins in 90 phylogenetically diverse eukaryotes. The resulting ortholog sets imply that the last eukaryotic common ancestor (LECA) possessed a complex kinetochore and highlight that current‐day kinetochores differ substantially. These kinetochores diverged through gene loss, duplication, and, less frequently, invention and displacement. Various kinetochore components co‐evolved with one another, albeit in different manners. These co‐evolutionary patterns improve our understanding of kinetochore function and evolution, which we illustrated with the RZZ complex, TRIP13, the MCC, and some nuclear pore proteins. The extensive diversity of kinetochore compositions in eukaryotes poses numerous questions regarding evolutionary flexibility of essential cellular functions.
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Affiliation(s)
- Jolien Je van Hooff
- Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands.,Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands.,Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Eelco Tromer
- Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands.,Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | - Leny M van Wijk
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | - Geert Jpl Kops
- Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands .,Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands.,Cancer Genomics Netherlands, University Medical Center Utrecht, Utrecht, The Netherlands
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53
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Hammond RG, Tan X, Johnson MA. SARS-unique fold in the Rousettus bat coronavirus HKU9. Protein Sci 2017; 26:1726-1737. [PMID: 28580734 PMCID: PMC5563143 DOI: 10.1002/pro.3208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/26/2017] [Accepted: 05/26/2017] [Indexed: 12/28/2022]
Abstract
The coronavirus nonstructural protein 3 (nsp3) is a multifunctional protein that comprises multiple structural domains. This protein assists viral polyprotein cleavage, host immune interference, and may play other roles in genome replication or transcription. Here, we report the solution NMR structure of a protein from the “SARS‐unique region” of the bat coronavirus HKU9. The protein contains a frataxin fold or double‐wing motif, which is an α + β fold that is associated with protein/protein interactions, DNA binding, and metal ion binding. High structural similarity to the human severe acute respiratory syndrome (SARS) coronavirus nsp3 is present. A possible functional site that is conserved among some betacoronaviruses has been identified using bioinformatics and biochemical analyses. This structure provides strong experimental support for the recent proposal advanced by us and others that the “SARS‐unique” region is not unique to the human SARS virus, but is conserved among several different phylogenetic groups of coronaviruses and provides essential functions. PDB Code(s): 5UTV
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Affiliation(s)
- Robert G Hammond
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Xuan Tan
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Margaret A Johnson
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama, 35294
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54
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McKinley KL, Cheeseman IM. Large-Scale Analysis of CRISPR/Cas9 Cell-Cycle Knockouts Reveals the Diversity of p53-Dependent Responses to Cell-Cycle Defects. Dev Cell 2017; 40:405-420.e2. [PMID: 28216383 DOI: 10.1016/j.devcel.2017.01.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/23/2016] [Accepted: 01/23/2017] [Indexed: 12/20/2022]
Abstract
Defining the genes that are essential for cellular proliferation is critical for understanding organismal development and identifying high-value targets for disease therapies. However, the requirements for cell-cycle progression in human cells remain incompletely understood. To elucidate the consequences of acute and chronic elimination of cell-cycle proteins, we generated and characterized inducible CRISPR/Cas9 knockout human cell lines targeting 209 genes involved in diverse cell-cycle processes. We performed single-cell microscopic analyses to systematically establish the effects of the knockouts on subcellular architecture. To define variations in cell-cycle requirements between cultured cell lines, we generated knockouts across cell lines of diverse origins. We demonstrate that p53 modulates the phenotype of specific cell-cycle defects through distinct mechanisms, depending on the defect. This work provides a resource to broadly facilitate robust and long-term depletion of cell-cycle proteins and reveals insights into the requirements for cell-cycle progression.
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Affiliation(s)
- Kara L McKinley
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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55
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Musacchio A, Desai A. A Molecular View of Kinetochore Assembly and Function. BIOLOGY 2017; 6:E5. [PMID: 28125021 PMCID: PMC5371998 DOI: 10.3390/biology6010005] [Citation(s) in RCA: 354] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/16/2017] [Accepted: 01/17/2017] [Indexed: 12/15/2022]
Abstract
Kinetochores are large protein assemblies that connect chromosomes to microtubules of the mitotic and meiotic spindles in order to distribute the replicated genome from a mother cell to its daughters. Kinetochores also control feedback mechanisms responsible for the correction of incorrect microtubule attachments, and for the coordination of chromosome attachment with cell cycle progression. Finally, kinetochores contribute to their own preservation, across generations, at the specific chromosomal loci devoted to host them, the centromeres. They achieve this in most species by exploiting an epigenetic, DNA-sequence-independent mechanism; notable exceptions are budding yeasts where a specific sequence is associated with centromere function. In the last 15 years, extensive progress in the elucidation of the composition of the kinetochore and the identification of various physical and functional modules within its substructure has led to a much deeper molecular understanding of kinetochore organization and the origins of its functional output. Here, we provide a broad summary of this progress, focusing primarily on kinetochores of humans and budding yeast, while highlighting work from other models, and present important unresolved questions for future studies.
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Affiliation(s)
- Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, Dortmund 44227, Germany.
- Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen 45117, Germany.
| | - Arshad Desai
- Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA.
- Department of Cellular & Molecular Medicine, 9500 Gilman Dr., La Jolla, CA 92093, USA.
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56
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Evolutionary Lessons from Species with Unique Kinetochores. CENTROMERES AND KINETOCHORES 2017; 56:111-138. [DOI: 10.1007/978-3-319-58592-5_5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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57
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Huis In 't Veld PJ, Jeganathan S, Petrovic A, Singh P, John J, Krenn V, Weissmann F, Bange T, Musacchio A. Molecular basis of outer kinetochore assembly on CENP-T. eLife 2016; 5. [PMID: 28012276 PMCID: PMC5241120 DOI: 10.7554/elife.21007] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/23/2016] [Indexed: 12/23/2022] Open
Abstract
Stable kinetochore-microtubule attachment is essential for cell division. It requires recruitment of outer kinetochore microtubule binders by centromere proteins C and T (CENP-C and CENP-T). To study the molecular requirements of kinetochore formation, we reconstituted the binding of the MIS12 and NDC80 outer kinetochore subcomplexes to CENP-C and CENP-T. Whereas CENP-C recruits a single MIS12:NDC80 complex, we show here that CENP-T binds one MIS12:NDC80 and two NDC80 complexes upon phosphorylation by the mitotic CDK1:Cyclin B complex at three distinct CENP-T sites. Visualization of reconstituted complexes by electron microscopy supports this model. Binding of CENP-C and CENP-T to MIS12 is competitive, and therefore CENP-C and CENP-T act in parallel to recruit two MIS12 and up to four NDC80 complexes. Our observations provide a molecular explanation for the stoichiometry of kinetochore components and its cell cycle regulation, and highlight how outer kinetochore modules bridge distances of well over 100 nm. DOI:http://dx.doi.org/10.7554/eLife.21007.001
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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
| | - Sadasivam Jeganathan
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Arsen Petrovic
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Priyanka Singh
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Juliane John
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Veronica Krenn
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Florian Weissmann
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.,Vienna Biocenter (VBC), Vienna, Austria
| | - Tanja Bange
- 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, University Duisburg-Essen, Essen, Germany.,Faculty of Biology, University Duisburg-Essen, Essen, Germany
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58
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CENP-A and H3 Nucleosomes Display a Similar Stability to Force-Mediated Disassembly. PLoS One 2016; 11:e0165078. [PMID: 27820823 PMCID: PMC5098787 DOI: 10.1371/journal.pone.0165078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 10/05/2016] [Indexed: 12/12/2022] Open
Abstract
Centromere-specific nucleosomes are a central feature of the kinetochore complex during mitosis, in which microtubules exert pulling and pushing forces upon the centromere. CENP-A nucleosomes have been assumed to be structurally unique, thereby providing resilience under tension relative to their H3 canonical counterparts. Here, we directly test this hypothesis by subjecting CENP-A and H3 octameric nucleosomes, assembled on random or on centromeric DNA sequences, to varying amounts of applied force by using single-molecule magnetic tweezers. We monitor individual disassembly events of CENP-A and H3 nucleosomes. Regardless of the DNA sequence, the force-mediated disassembly experiments for CENP-A and H3 nucleosomes demonstrate similar rupture forces, life time residency and disassembly steps. From these experiments, we conclude that CENP-A does not, by itself, contribute unique structural features to the nucleosome that lead to a significant resistance against force-mediated disruption. The data present insights into the mechanistic basis for how CENP-A nucleosomes might contribute to the structural foundation of the centromere in vivo.
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59
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Liu Y, Petrovic A, Rombaut P, Mosalaganti S, Keller J, Raunser S, Herzog F, Musacchio A. Insights from the reconstitution of the divergent outer kinetochore of Drosophila melanogaster. Open Biol 2016; 6:150236. [PMID: 26911624 PMCID: PMC4772808 DOI: 10.1098/rsob.150236] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Accurate chromosome segregation during mitosis and meiosis is crucial for cellular and organismal viability. Kinetochores connect chromosomes with spindle microtubules and are essential for chromosome segregation. These large protein scaffolds emerge from the centromere, a specialized region of the chromosome enriched with the histone H3 variant CENP-A. In most eukaryotes, the kinetochore core consists of the centromere-proximal constitutive centromere-associated network (CCAN), which binds CENP-A and contains 16 subunits, and of the centromere-distal Knl1 complex, Mis12 complex, Ndc80 complex (KMN) network, which binds microtubules and contains 10 subunits. In the fruitfly, Drosophila melanogaster, the kinetochore underwent remarkable simplifications. All CCAN subunits, with the exception of centromeric protein C (CENP-C), and two KMN subunits, Dsn1 and Zwint, cannot be identified in this organism. In addition, two paralogues of the KMN subunit Nnf1 (Nnf1a and Nnf1b) are present. Finally, the Spc105R subunit, homologous to human Knl1/CASC5, underwent considerable sequence changes in comparison with other organisms. We combined biochemical reconstitution with biophysical and structural methods to investigate how these changes reflect on the organization of the Drosophila KMN network. We demonstrate that the Nnf1a and Nnf1b paralogues are subunits of distinct complexes, both of which interact directly with Spc105R and with CENP-C, for the latter of which we identify a binding site on the Mis12 subunit. Our studies shed light on the structural and functional organization of a highly divergent kinetochore particle.
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Affiliation(s)
- Yahui Liu
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Arsen Petrovic
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Pascaline Rombaut
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Shyamal Mosalaganti
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Jenny Keller
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Franz Herzog
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstraße, 45141 Essen, Germany
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60
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Abstract
Post-translational modification (PTM) of proteins by ubiquitination is an essential cellular regulatory process. Such regulation drives the cell cycle and cell division, signalling and secretory pathways, DNA replication and repair processes and protein quality control and degradation pathways. A huge range of ubiquitin signals can be generated depending on the specificity and catalytic activity of the enzymes required for attachment of ubiquitin to a given target. As a consequence of its importance to eukaryotic life, dysfunction in the ubiquitin system leads to many disease states, including cancers and neurodegeneration. This review takes a retrospective look at our progress in understanding the molecular mechanisms that govern the specificity of ubiquitin conjugation.
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61
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Dimitrova YN, Jenni S, Valverde R, Khin Y, Harrison SC. Structure of the MIND Complex Defines a Regulatory Focus for Yeast Kinetochore Assembly. Cell 2016; 167:1014-1027.e12. [PMID: 27881300 PMCID: PMC5856483 DOI: 10.1016/j.cell.2016.10.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/02/2016] [Accepted: 10/03/2016] [Indexed: 11/25/2022]
Abstract
Kinetochores connect centromeric nucleosomes with mitotic-spindle microtubules through conserved, cross-interacting protein subassemblies. In budding yeast, the heterotetrameric MIND complex (Mtw1, Nnf1, Nsl1, Dsn1), ortholog of the metazoan Mis12 complex, joins the centromere-proximal components, Mif2 and COMA, with the principal microtubule-binding component, the Ndc80 complex (Ndc80C). We report the crystal structure of Kluyveromyces lactis MIND and examine its partner interactions, to understand the connection from a centromeric nucleosome to a much larger microtubule. MIND resembles an elongated, asymmetric Y; two globular heads project from a coiled-coil shaft. An N-terminal extension of Dsn1 from one head regulates interactions of the other head, blocking binding of Mif2 and COMA. Dsn1 phosphorylation by Ipl1/Aurora B relieves this autoinhibition, enabling MIND to join an assembling kinetochore. A C-terminal extension of Dsn1 recruits Ndc80C to the opposite end of the shaft. The structure and properties of MIND show how it integrates phospho-regulatory inputs for kinetochore assembly and disassembly.
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Affiliation(s)
- Yoana N Dimitrova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Roberto Valverde
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Yadana Khin
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, 250 Longwood Avenue, Boston, MA 02115, USA.
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62
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Petrovic A, Keller J, Liu Y, Overlack K, John J, Dimitrova YN, Jenni S, van Gerwen S, Stege P, Wohlgemuth S, Rombaut P, Herzog F, Harrison SC, Vetter IR, Musacchio A. Structure of the MIS12 Complex and Molecular Basis of Its Interaction with CENP-C at Human Kinetochores. Cell 2016; 167:1028-1040.e15. [PMID: 27881301 PMCID: PMC5101189 DOI: 10.1016/j.cell.2016.10.005] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/16/2016] [Accepted: 10/03/2016] [Indexed: 01/14/2023]
Abstract
Kinetochores, multisubunit protein assemblies, connect chromosomes to spindle microtubules to promote chromosome segregation. The 10-subunit KMN assembly (comprising KNL1, MIS12, and NDC80 complexes, designated KNL1C, MIS12C, and NDC80C) binds microtubules and regulates mitotic checkpoint function through NDC80C and KNL1C, respectively. MIS12C, on the other hand, connects the KMN to the chromosome-proximal domain of the kinetochore through a direct interaction with CENP-C. The structural basis for this crucial bridging function of MIS12C is unknown. Here, we report crystal structures of human MIS12C associated with a fragment of CENP-C and unveil the role of Aurora B kinase in the regulation of this interaction. The structure of MIS12:CENP-C complements previously determined high-resolution structures of functional regions of NDC80C and KNL1C and allows us to build a near-complete structural model of the KMN assembly. Our work illuminates the structural organization of essential chromosome segregation machinery that is conserved in most eukaryotes. We report a crystal structure of human MIS12 complex, a crucial kinetochore component The structure reveals how the MIS12 complex binds its kinetochore receptor CENP-C We dissect how Aurora B kinase promotes the MIS12:CENP-C interaction A combination of diverse structural methods reveals outer kinetochore organization
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Affiliation(s)
- Arsen Petrovic
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.
| | - Jenny Keller
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Yahui Liu
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Katharina Overlack
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Juliane John
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Yoana N Dimitrova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115
| | - Suzan van Gerwen
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Patricia Stege
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Sabine Wohlgemuth
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Pascaline Rombaut
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Franz Herzog
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115; Department of Biological Chemistry and Molecular Pharmacology, Howard Hughes Medical Institute, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115
| | - Ingrid R Vetter
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Faculty of Biology, Centre for Medical Biotechnology, University Duisburg-Essen, Universitätsstrasse, 45141 Essen, Germany.
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63
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Abad MA, Zou J, Medina-Pritchard B, Nigg EA, Rappsilber J, Santamaria A, Jeyaprakash AA. Ska3 Ensures Timely Mitotic Progression by Interacting Directly With Microtubules and Ska1 Microtubule Binding Domain. Sci Rep 2016; 6:34042. [PMID: 27667719 PMCID: PMC5036024 DOI: 10.1038/srep34042] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/07/2016] [Indexed: 12/19/2022] Open
Abstract
The establishment of physical attachment between the kinetochore and dynamic spindle microtubules, which undergo cycles of polymerization and depolymerization generating straight and curved microtubule structures, is essential for accurate chromosome segregation. The Ndc80 and Ska complexes are the major microtubule-binding factors of the kinetochore responsible for maintaining chromosome-microtubule coupling during chromosome segregation. We previously showed that the Ska1 subunit of the Ska complex binds dynamic microtubules using multiple contact sites in a mode that allows conformation-independent binding. Here, we show that the Ska3 subunit is required to modulate the microtubule binding capability of the Ska complex (i) by directly interacting with tubulin monomers and (ii) indirectly by interacting with tubulin contacting regions of Ska1 suggesting an allosteric regulation. Perturbing either the Ska3-microtubule interaction or the Ska3-Ska1 interactions negatively influences microtubule binding by the Ska complex in vitro and affects the timely onset of anaphase in cells. Thus, Ska3 employs additional modulatory elements within the Ska complex to ensure robust kinetochore-microtubule attachments and timely progression of mitosis.
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Affiliation(s)
- Maria Alba Abad
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF UK
| | - Juan Zou
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF UK
| | - Bethan Medina-Pritchard
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF UK
| | - Erich A Nigg
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF UK.,Chair of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - Anna Santamaria
- Cell Cycle and Cancer, Group of Biomedical Research in Gynaecology, Vall d'Hebron Research Institute, Barcelona, Spain
| | - A Arockia Jeyaprakash
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF UK
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64
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Morelli E, Mastrodonato V, Beznoussenko GV, Mironov AA, Tognon E, Vaccari T. An essential step of kinetochore formation controlled by the SNARE protein Snap29. EMBO J 2016; 35:2223-2237. [PMID: 27647876 PMCID: PMC5069552 DOI: 10.15252/embj.201693991] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 08/16/2016] [Indexed: 12/31/2022] Open
Abstract
The kinetochore is an essential structure that mediates accurate chromosome segregation in mitosis and meiosis. While many of the kinetochore components have been identified, the mechanisms of kinetochore assembly remain elusive. Here, we identify a novel role for Snap29, an unconventional SNARE, in promoting kinetochore assembly during mitosis in Drosophila and human cells. Snap29 localizes to the outer kinetochore and prevents chromosome mis‐segregation and the formation of cells with fragmented nuclei. Snap29 promotes accurate chromosome segregation by mediating the recruitment of Knl1 at the kinetochore and ensuring stable microtubule attachments. Correct Knl1 localization to kinetochore requires human or Drosophila Snap29, and is prevented by a Snap29 point mutant that blocks Snap29 release from SNARE fusion complexes. Such mutant causes ectopic Knl1 recruitment to trafficking compartments. We propose that part of the outer kinetochore is functionally similar to membrane fusion interfaces.
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Affiliation(s)
- Elena Morelli
- IFOM, The FIRC Institute of Molecular Oncology, Milan, Italy
| | | | | | | | - Emiliana Tognon
- IFOM, The FIRC Institute of Molecular Oncology, Milan, Italy
| | - Thomas Vaccari
- IFOM, The FIRC Institute of Molecular Oncology, Milan, Italy
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65
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Smith CA, McAinsh AD, Burroughs NJ. Human kinetochores are swivel joints that mediate microtubule attachments. eLife 2016; 5. [PMID: 27591356 PMCID: PMC5050023 DOI: 10.7554/elife.16159] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 09/02/2016] [Indexed: 11/16/2022] Open
Abstract
Chromosome segregation is a mechanical process that requires assembly of the mitotic spindle – a dynamic microtubule-based force-generating machine. Connections to this spindle are mediated by sister kinetochore pairs, that form dynamic end-on attachments to microtubules emanating from opposite spindle poles. This bi-orientation generates forces that have been reported to stretch the kinetochore itself, which has been suggested to stabilise attachment and silence the spindle checkpoint. We reveal using three dimensional tracking that the outer kinetochore domain can swivel around the inner kinetochore/centromere, which results in large reductions in intra-kinetochore distance (delta) when viewed in lower dimensions. We show that swivel provides a mechanical flexibility that enables kinetochores at the periphery of the spindle to engage microtubules. Swivel reduces as cells approach anaphase, suggesting an organisational change linked to checkpoint satisfaction and/or obligatory changes in kinetochore mechanochemistry may occur before dissolution of sister chromatid cohesion. DOI:http://dx.doi.org/10.7554/eLife.16159.001
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Affiliation(s)
- Chris A Smith
- Centre for Mechanochemical Cell Biology, Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom.,Molecular Organisation and Assembly in Cells (MOAC) Doctoral Training Centre, University of Warwick, Coventry, United Kingdom
| | - Andrew D McAinsh
- Centre for Mechanochemical Cell Biology, Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Nigel J Burroughs
- Warwick Systems Biology Centre, University of Warwick, Coventry, United Kingdom.,Mathematics Institute, University of Warwick, Coventry, United Kingdom
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66
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Weir JR, Faesen AC, Klare K, Petrovic A, Basilico F, Fischböck J, Pentakota S, Keller J, Pesenti ME, Pan D, Vogt D, Wohlgemuth S, Herzog F, Musacchio A. Insights from biochemical reconstitution into the architecture of human kinetochores. Nature 2016; 537:249-253. [PMID: 27580032 DOI: 10.1038/nature19333] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 07/25/2016] [Indexed: 12/15/2022]
Abstract
Chromosomes are carriers of genetic material and their accurate transfer from a mother cell to its two daughters during cell division is of paramount importance for life. Kinetochores are crucial for this process, as they connect chromosomes with microtubules in the mitotic spindle. Kinetochores are multi-subunit complexes that assemble on specialized chromatin domains, the centromeres, that are able to enrich nucleosomes containing the histone H3 variant centromeric protein A (CENP-A). A group of several additional CENPs, collectively known as constitutive centromere associated network (CCAN), establish the inner kinetochore, whereas a ten-subunit assembly known as the KMN network creates a microtubule-binding site in the outer kinetochore. Interactions between CENP-A and two CCAN subunits, CENP-C and CENP-N, have been previously described, but a comprehensive understanding of CCAN organization and of how it contributes to the selective recognition of CENP-A has been missing. Here we use biochemical reconstitution to unveil fundamental principles of kinetochore organization and function. We show that cooperative interactions of a seven-subunit CCAN subcomplex, the CHIKMLN complex, determine binding selectivity for CENP-A over H3-nucleosomes. The CENP-A:CHIKMLN complex binds directly to the KMN network, resulting in a 21-subunit complex that forms a minimal high-affinity linkage between CENP-A nucleosomes and microtubules in vitro. This structural module is related to fungal point kinetochores, which bind a single microtubule. Its convolution with multiple CENP-A proteins may give rise to the regional kinetochores of higher eukaryotes, which bind multiple microtubules. Biochemical reconstitution paves the way for mechanistic and quantitative analyses of kinetochores.
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Affiliation(s)
- John R Weir
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Alex C Faesen
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Kerstin Klare
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Arsen Petrovic
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Federica Basilico
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Josef Fischböck
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany
| | - Satyakrishna Pentakota
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Jenny Keller
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Marion E Pesenti
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Dongqing Pan
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Doro Vogt
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Sabine Wohlgemuth
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Franz Herzog
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.,Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstraße, 45141 Essen, Germany
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67
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Magidson V, He J, Ault JG, O'Connell CB, Yang N, Tikhonenko I, McEwen BF, Sui H, Khodjakov A. Unattached kinetochores rather than intrakinetochore tension arrest mitosis in taxol-treated cells. J Cell Biol 2016; 212:307-19. [PMID: 26833787 PMCID: PMC4748573 DOI: 10.1083/jcb.201412139] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Taxol induces extensive structural reorganization of the mammalian kinetochore; however, this reorganization is not sufficient to maintain a long-term mitotic arrest unless some of the kinetochores completely lose their attachment to microtubules. Kinetochores attach chromosomes to the spindle microtubules and signal the spindle assembly checkpoint to delay mitotic exit until all chromosomes are attached. Light microscopy approaches aimed to indirectly determine distances between various proteins within the kinetochore (termed Delta) suggest that kinetochores become stretched by spindle forces and compact elastically when the force is suppressed. Low Delta is believed to arrest mitotic progression in taxol-treated cells. However, the structural basis of Delta remains unknown. By integrating same-kinetochore light microscopy and electron microscopy, we demonstrate that the value of Delta is affected by the variability in the shape and size of outer kinetochore domains. The outer kinetochore compacts when spindle forces are maximal during metaphase. When the forces are weakened by taxol treatment, the outer kinetochore expands radially and some kinetochores completely lose microtubule attachment, a condition known to arrest mitotic progression. These observations offer an alternative interpretation of intrakinetochore tension and question whether Delta plays a direct role in the control of mitotic progression.
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Affiliation(s)
- Valentin Magidson
- Wadsworth Center, New York State Department of Health, Albany, NY 12201
| | - Jie He
- Wadsworth Center, New York State Department of Health, Albany, NY 12201
| | - Jeffrey G Ault
- Wadsworth Center, New York State Department of Health, Albany, NY 12201
| | | | - Nachen Yang
- Wadsworth Center, New York State Department of Health, Albany, NY 12201
| | - Irina Tikhonenko
- Wadsworth Center, New York State Department of Health, Albany, NY 12201
| | - Bruce F McEwen
- Wadsworth Center, New York State Department of Health, Albany, NY 12201 School of Public Health, State University of New York, Albany, NY 12201
| | - Haixin Sui
- Wadsworth Center, New York State Department of Health, Albany, NY 12201 School of Public Health, State University of New York, Albany, NY 12201
| | - Alexey Khodjakov
- Wadsworth Center, New York State Department of Health, Albany, NY 12201 Rensselaer Polytechnic Institute, Troy, NY 12180
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68
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biGBac enables rapid gene assembly for the expression of large multisubunit protein complexes. Proc Natl Acad Sci U S A 2016; 113:E2564-9. [PMID: 27114506 DOI: 10.1073/pnas.1604935113] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Analyses of protein complexes are facilitated by methods that enable the generation of recombinant complexes via coexpression of their subunits from multigene DNA constructs. However, low experimental throughput limits the generation of such constructs in parallel. Here we describe a method that allows up to 25 cDNAs to be assembled into a single baculoviral expression vector in only two steps. This method, called biGBac, uses computationally optimized DNA linker sequences that enable the efficient assembly of linear DNA fragments, using reactions developed by Gibson for the generation of synthetic genomes. The biGBac method uses a flexible and modular "mix and match" approach and enables the generation of baculoviruses from DNA constructs at any assembly stage. Importantly, it is simple, efficient, and fast enough to allow the manual generation of many multigene expression constructs in parallel. We have used this method to generate and characterize recombinant forms of the anaphase-promoting complex/cyclosome, cohesin, and kinetochore complexes.
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69
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Friese A, Faesen AC, Huis in 't Veld PJ, Fischböck J, Prumbaum D, Petrovic A, Raunser S, Herzog F, Musacchio A. Molecular requirements for the inter-subunit interaction and kinetochore recruitment of SKAP and Astrin. Nat Commun 2016; 7:11407. [PMID: 27095104 PMCID: PMC4843017 DOI: 10.1038/ncomms11407] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 03/22/2016] [Indexed: 12/18/2022] Open
Abstract
Accurate chromosome segregation during cell division is crucial for propagating life and protects from cellular transformation. The SKAP:Astrin heterodimer localizes to spindle microtubules and to mature microtubule–kinetochore attachments during mitosis. Depletion of either subunit disrupts spindle structure and destabilizes kinetochore–microtubule attachments. Here, we identify molecular requirements for the inter-subunit interaction of SKAP and Astrin, and discuss requirements for their kinetochore recruitment. We also identify and characterize a microtubule-binding domain in SKAP, distinct from the SXIP motif that mediates end binding (EB) protein binding and plus end tracking, and show that it stimulates the growth-rate of microtubules, possibly through a direct interaction with tubulin. Mutations targeting this microtubule-binding domain impair microtubule plus-end tracking but not kinetochore targeting, and recapitulate many effects observed during depletion of SKAP. Collectively, our studies represent the first thorough mechanistic analysis of SKAP and Astrin, and significantly advance our functional understanding of these important mitotic proteins. SKAP and Astrin form a heterodimer that localizes to spindle microtubules and to mature microtubule-kinetochore attachments during mitosis. Here, the authors identify molecular requirements for the inter-subunit interaction of SKAP and Astrin and kinetochore recruitment.
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Affiliation(s)
- Alexandra Friese
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Alex C Faesen
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Pim J Huis in 't Veld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Josef Fischböck
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany
| | - Daniel Prumbaum
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Arsen Petrovic
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Franz Herzog
- Gene Center Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.,Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstrasse, 45141 Essen, Germany
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70
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Pesenti ME, Weir JR, Musacchio A. Progress in the structural and functional characterization of kinetochores. Curr Opin Struct Biol 2016; 37:152-63. [PMID: 27039078 DOI: 10.1016/j.sbi.2016.03.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/10/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
Abstract
Kinetochores are macromolecular complexes built on a specialized chromatin domain called the centromere. Kinetochores provide a site of attachment for spindle microtubules during mitosis. They also control a cell cycle checkpoint, the spindle assembly checkpoint, which coordinates mitotic exit with the completion of chromosome alignment on the mitotic spindle. Correct kinetochore operation is therefore indispensable for accurate chromosome segregation. With multiple copies of at least 30 structural core subunits and a myriad of regulatory subunits, kinetochores are among the largest known macromolecular machines. Biochemical reconstitution and structural analysis, together with functional studies, are bringing to light the organizational principles of these complex and fascinating structures. We summarize recent work and identify a few challenges for future work.
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Affiliation(s)
- Marion E Pesenti
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - John R Weir
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstraße, 45141 Essen, Germany.
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71
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Singleton MR. Getting to the heart of an unusual kinetochore. Open Biol 2016; 6:160040. [PMID: 27249344 PMCID: PMC4852463 DOI: 10.1098/rsob.160040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/18/2016] [Indexed: 11/18/2022] Open
Abstract
The Mis12 complex forms the central scaffold of the kinetochore and serves to bridge the chromatin and microtubule-binding activities of the inner and outer layers, respectively. Two recent studies provide new structural insights into the formation of this complex, and highlight some intriguing adaptations found in the Drosophila kinetochore.
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Affiliation(s)
- Martin R Singleton
- Structural Biology of Chromosome Segregation Laboratory, The Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
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72
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Nerusheva OO, Akiyoshi B. Divergent polo box domains underpin the unique kinetoplastid kinetochore. Open Biol 2016; 6:150206. [PMID: 26984294 PMCID: PMC4821238 DOI: 10.1098/rsob.150206] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/21/2016] [Indexed: 11/12/2022] Open
Abstract
Kinetochores are macromolecular machines that drive eukaryotic chromosome segregation by interacting with centromeric DNA and spindle microtubules. While most eukaryotes possess conventional kinetochore proteins, evolutionarily distant kinetoplastid species have unconventional kinetochore proteins, composed of at least 19 proteins (KKT1-19). Polo-like kinase (PLK) is not a structural kinetochore component in either system. Here, we report the identification of an additional kinetochore protein, KKT20, in Trypanosoma brucei. KKT20 has sequence similarity with KKT2 and KKT3 in the Cys-rich region, and all three proteins have weak but significant similarity to the polo box domain (PBD) of PLK. These divergent PBDs of KKT2 and KKT20 are sufficient for kinetochore localization in vivo. We propose that the ancestral PLK acquired a Cys-rich region and then underwent gene duplication events to give rise to three structural kinetochore proteins in kinetoplastids.
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Affiliation(s)
| | - Bungo Akiyoshi
- Department of Biochemistry, University of Oxford, Oxford, UK
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73
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Freitag M. The kinetochore interaction network (KIN) of ascomycetes. Mycologia 2016; 108:485-505. [PMID: 26908646 DOI: 10.3852/15-182] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 10/23/2015] [Indexed: 01/13/2023]
Abstract
Chromosome segregation relies on coordinated activity of a large assembly of proteins, the kinetochore interaction network (KIN). How conserved the underlying mechanisms driving the epigenetic phenomenon of centromere and kinetochore assembly and maintenance are remains unclear, even though various eukaryotic models have been studied. More than 50 different proteins, many in multiple copies, comprise the KIN or are associated with fungal centromeres and kinetochores. Proteins isolated from immune sera recognized centromeric regions on chromosomes and thus were named centromere proteins (CENPs). CENP-A, sometimes called centromere-specific H3 (CenH3), is incorporated into nucleosomes within or near centromeres. The constitutive centromere-associated network (CCAN) assembles on this specialized chromatin, likely based on specific interactions with and requiring presence of CENP-C. The outer kinetochore comprises the Knl1-Mis12-Ndc80 (KMN) protein complexes that connect CCAN to spindles, accomplished by binding and stabilizing microtubules (MTs) and in the process generating load-bearing assemblies for chromatid segregation. In most fungi the Dam1/DASH complex connects the KMN complexes to MTs. Fungi present a rich resource to investigate mechanistic commonalities but also differences in kinetochore architecture. While ascomycetes have sets of CCAN and KMN proteins that are conserved with those of budding yeast or metazoans, searching other major branches of the fungal kingdom revealed that CCAN proteins are poorly conserved at the primary sequence level. Several conserved binding motifs or domains within KMN complexes have been described recently, and these features of ascomycete KIN proteins are shared with most metazoan proteins. In addition, several ascomycete-specific domains have been identified here.
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Affiliation(s)
- Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331-7305
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74
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Drosophila Nnf1 paralogs are partially redundant for somatic and germ line kinetochore function. Chromosoma 2016; 126:145-163. [DOI: 10.1007/s00412-016-0579-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 02/03/2016] [Accepted: 02/08/2016] [Indexed: 10/22/2022]
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75
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Richter MM, Poznanski J, Zdziarska A, Czarnocki-Cieciura M, Lipinszki Z, Dadlez M, Glover DM, Przewloka MR. Network of protein interactions within the Drosophila inner kinetochore. Open Biol 2016; 6:150238. [PMID: 26911623 PMCID: PMC4772809 DOI: 10.1098/rsob.150238] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/01/2016] [Indexed: 12/27/2022] Open
Abstract
The kinetochore provides a physical connection between microtubules and the centromeric regions of chromosomes that is critical for their equitable segregation. The trimeric Mis12 sub-complex of the Drosophila kinetochore binds to the mitotic centromere using CENP-C as a platform. However, knowledge of the precise connections between Mis12 complex components and CENP-C has remained elusive despite the fundamental importance of this part of the cell division machinery. Here, we employ hydrogen-deuterium exchange coupled with mass spectrometry to reveal that Mis12 and Nnf1 form a dimer maintained by interacting coiled-coil (CC) domains within the carboxy-terminal parts of both proteins. Adjacent to these interacting CCs is a carboxy-terminal domain that also interacts with Nsl1. The amino-terminal parts of Mis12 and Nnf1 form a CENP-C-binding surface, which docks the complex and thus the entire kinetochore to mitotic centromeres. Mutational analysis confirms these precise interactions are critical for both structure and function of the complex. Thus, we conclude the organization of the Mis12-Nnf1 dimer confers upon the Mis12 complex a bipolar, elongated structure that is critical for kinetochore function.
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Affiliation(s)
- Magdalena M Richter
- Department of Genetics, University of Cambridge, Cambridge, UK Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, Poland
| | - Jaroslaw Poznanski
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, Poland
| | - Anna Zdziarska
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, Poland
| | - Mariusz Czarnocki-Cieciura
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, Poland Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | | | - Michal Dadlez
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, Poland Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - David M Glover
- Department of Genetics, University of Cambridge, Cambridge, UK
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76
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Tantos A, Kalmar L, Tompa P. The role of structural disorder in cell cycle regulation, related clinical proteomics, disease development and drug targeting. Expert Rev Proteomics 2016; 12:221-33. [PMID: 25976105 DOI: 10.1586/14789450.2015.1042866] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Understanding the molecular mechanisms of the regulation of cell cycle is a central issue in molecular cell biology, due to its fundamental role in the existence of cells. The regulatory circuits that make decisions on when a cell should divide are very complex and particularly subtly balanced in eukaryotes, in which the harmony of many different cells in an organism is essential for life. Several hundred proteins are involved in these processes, and a great deal of studies attests that most of them have functionally relevant intrinsic structural disorder. Structural disorder imparts many functional advantages on these proteins, and we discuss it in detail that it is involved in all key steps from signaling through the cell membrane to regulating transcription of proteins that execute timely responses to an ever-changing environment.
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Affiliation(s)
- Agnes Tantos
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
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77
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Wynne DJ, Funabiki H. Kinetochore function is controlled by a phospho-dependent coexpansion of inner and outer components. J Cell Biol 2015; 210:899-916. [PMID: 26347137 PMCID: PMC4576862 DOI: 10.1083/jcb.201506020] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is widely accepted that the kinetochore is built on CENP-A-marked centromeric chromatin in a hierarchical order from inner to outer kinetochore. Recruitment of many kinetochore proteins depends on microtubule attachment status, but it remains unclear how their assembly/disassembly is orchestrated. Applying 3D structured illumination microscopy to Xenopus laevis egg extracts, here we reveal that in the absence of microtubule attachment, proteins responsible for lateral attachment and spindle checkpoint signaling expand to form micrometer-scale fibrous structures over CENP-A-free chromatin, whereas a core module responsible for end-on attachment (CENP-A, CENP-T, and Ndc80) does not. Both outer kinetochore proteins (Bub1, BubR1, Mad1, and CENP-E) and the inner kinetochore component CENP-C are integral components of the expandable module, whose assembly depends on multiple mitotic kinases (Aurora B, Mps1, and Plx1) and is suppressed by protein phosphatase 1. We propose that phospho-dependent coexpansion of CENP-C and outer kinetochore proteins promotes checkpoint signal amplification and lateral attachment, whereas their selective disassembly enables the transition to end-on attachment.
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78
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Samejima I, Spanos C, Alves FDL, Hori T, Perpelescu M, Zou J, Rappsilber J, Fukagawa T, Earnshaw WC. Whole-proteome genetic analysis of dependencies in assembly of a vertebrate kinetochore. J Cell Biol 2015; 211:1141-56. [PMID: 26668330 PMCID: PMC4687880 DOI: 10.1083/jcb.201508072] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/11/2015] [Indexed: 12/26/2022] Open
Abstract
Whole-proteome analysis of isolated mitotic chromosomes from 11 kinetochore structural and assembly mutants is used to develop dependency and correlation maps for protein subcomplexes that confirm many published interactions and also reveal novel dependencies between kinetochore components. Kinetochores orchestrate mitotic chromosome segregation. Here, we use quantitative mass spectrometry of mitotic chromosomes isolated from a comprehensive set of chicken DT40 mutants to examine the dependencies of 93 confirmed and putative kinetochore proteins for stable association with chromosomes. Clustering and network analysis reveal both known and unexpected aspects of coordinated behavior for members of kinetochore protein complexes. Surprisingly, CENP-T depends on CENP-N for chromosome localization. The Ndc80 complex exhibits robust correlations with all other complexes in a “core” kinetochore network. Ndc80 associated with CENP-T interacts with a cohort of Rod, zw10, and zwilch (RZZ)–interacting proteins that includes Spindly, Mad1, and CENP-E. This complex may coordinate microtubule binding with checkpoint signaling. Ndc80 associated with CENP-C forms the KMN (Knl1, Mis12, Ndc80) network and may be the microtubule-binding “workhorse” of the kinetochore. Our data also suggest that CENP-O and CENP-R may regulate the size of the inner kinetochore without influencing the assembly of the outer kinetochore.
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Affiliation(s)
- Itaru Samejima
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - Christos Spanos
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - Flavia de Lima Alves
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - Tetsuya Hori
- Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Marinela Perpelescu
- Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan
| | - Juan Zou
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK Department of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - Tatsuo Fukagawa
- Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
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79
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Szczepanski S, Hussain MS, Sur I, Altmüller J, Thiele H, Abdullah U, Waseem SS, Moawia A, Nürnberg G, Noegel AA, Baig SM, Nürnberg P. A novel homozygous splicing mutation of CASC5 causes primary microcephaly in a large Pakistani family. Hum Genet 2015; 135:157-70. [PMID: 26621532 DOI: 10.1007/s00439-015-1619-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 11/16/2015] [Indexed: 11/29/2022]
Abstract
Primary microcephaly is a disorder characterized by a small head and brain associated with impaired cognitive capabilities. Mutations in 13 different genes encoding centrosomal proteins and cell cycle regulators have been reported to cause the disease. CASC5, a gene encoding a protein important for kinetochore formation and proper chromosome segregation during mitosis, has been suggested to be associated with primary microcephaly-4 (MCPH4). This was based on one mutation only and circumstantial functional evidence. By combining homozygosity mapping and whole-exome sequencing in an MCPH family from Pakistan, we identified a second mutation (NM_170589.4;c.6673-19T>A) in CASC5. This mutation induced skipping of exon 25 of CASC5 resulting in a frameshift and the introduction of a premature stop codon (p.Met2225Ilefs*7). The C-terminally truncated protein lacks 118 amino acids that encompass the region responsible for the interaction with the hMIS12 complex, which is essential for proper chromosome alignment and segregation. Furthermore, we showed a down-regulation of CASC5 mRNA and reduction of the amount of CASC5 protein by quantitative RT-PCR and western blot analysis, respectively. As a further sign of functional deficits, we observed dispersed dots of CASC5 immunoreactive material outside the metaphase plate of dividing patient fibroblasts. Normally, CASC5 is a component of the kinetochore of metaphase chromosomes. A higher mitotic index in patient cells indicated a mitotic arrest in the cells carrying the mutation. We also observed lobulated and fragmented nuclei as well as micronuclei in the patient cells. Moreover, we detected an altered DNA damage response with higher levels of γH2AX and 53BP1 in mutant as compared to control fibroblasts. Our findings substantiate the proposed role of CASC5 for primary microcephaly and suggest that it also might be relevant for genome stability.
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Affiliation(s)
- Sandra Szczepanski
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Weyertal 115b, 50931, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Muhammad Sajid Hussain
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Weyertal 115b, 50931, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Ilknur Sur
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Weyertal 115b, 50931, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany
- Institute of Human Genetics, University of Cologne, 50931, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany
| | - Uzma Abdullah
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Syeda Seema Waseem
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Abubakar Moawia
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Gudrun Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany
| | - Angelika Anna Noegel
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany.
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Weyertal 115b, 50931, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany.
| | - Shahid Mahmood Baig
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Weyertal 115b, 50931, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany.
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80
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Escape from Mitotic Arrest: An Unexpected Connection Between Microtubule Dynamics and Epigenetic Regulation of Centromeric Chromatin in Schizosaccharomyces pombe. Genetics 2015; 201:1467-78. [PMID: 26510788 DOI: 10.1534/genetics.115.181792] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/23/2015] [Indexed: 01/02/2023] Open
Abstract
Accurate chromosome segregation is necessary to ensure genomic integrity. Segregation depends on the proper functioning of the centromere, kinetochore, and mitotic spindle microtubules and is monitored by the spindle assembly checkpoint (SAC). In the fission yeast Schizosaccharomyces pombe, defects in Dis1, a microtubule-associated protein that influences microtubule dynamics, lead to mitotic arrest as a result of an active SAC and consequent failure to grow at low temperature. In a mutant dis1 background (dis1-288), loss of function of Msc1, a fission yeast homolog of the KDM5 family of proteins, suppresses the growth defect and promotes normal mitosis. Genetic analysis implicates a histone deacetylase (HDAC)-linked pathway in suppression because HDAC mutants clr6-1, clr3∆, and sir2∆, though not hos2∆, also promote normal mitosis in the dis1-288 mutant. Suppression of the dis phenotype through loss of msc1 function requires the spindle checkpoint protein Mad2 and is limited by the presence of the heterochromatin-associated HP1 protein homolog Swi6. We speculate that alterations in histone acetylation promote a centromeric chromatin environment that compensates for compromised dis1 function by allowing for successful kinetochore-microtubule interactions that can satisfy the SAC. In cells arrested in mitosis by mutation of dis1, loss of function of epigenetic determinants such as Msc1 or specific HDACs can promote cell survival. Because the KDM5 family of proteins has been implicated in human cancers, an appreciation of the potential role of this family of proteins in chromosome segregation is warranted.
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81
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A quantitative description of Ndc80 complex linkage to human kinetochores. Nat Commun 2015; 6:8161. [PMID: 26345214 PMCID: PMC4569735 DOI: 10.1038/ncomms9161] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 07/25/2015] [Indexed: 11/08/2022] Open
Abstract
The Ndc80 complex, which mediates end-on attachment of spindle microtubules, is linked to centromeric chromatin in human cells by two inner kinetochore proteins, CENP-T and CENP-C. Here to quantify their relative contributions to Ndc80 recruitment, we combine measurements of kinetochore protein copy number with selective protein depletion assays. This approach reveals about 244 Ndc80 complexes per human kinetochore (∼14 per kinetochore microtubule), 215 CENP-C, 72 CENP-T and only 151 Ndc80s as part of the KMN protein network (1:1:1 Knl1, Mis12 and Ndc80 complexes). Each CENP-T molecule recruits ∼2 Ndc80 complexes; one as part of a KMN network. In contrast, ∼40% of CENP-C recruits only a KMN network. Replacing the CENP-C domain that binds KMN with the CENP-T domain that recruits both an Ndc80 complex and KMN network yielded functional kinetochores. These results provide a quantitative picture of the linkages between centromeric chromatin and the microtubule-binding Ndc80 complex at the human kinetochore.
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82
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Tromer E, Snel B, Kops GJPL. Widespread Recurrent Patterns of Rapid Repeat Evolution in the Kinetochore Scaffold KNL1. Genome Biol Evol 2015; 7:2383-93. [PMID: 26254484 PMCID: PMC4558858 DOI: 10.1093/gbe/evv140] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The outer kinetochore protein scaffold KNL1 is essential for error-free chromosome segregation during mitosis and meiosis. A critical feature of KNL1 is an array of repeats containing MELT-like motifs. When phosphorylated, these motifs form docking sites for the BUB1–BUB3 dimer that regulates chromosome biorientation and the spindle assembly checkpoint. KNL1 homologs are strikingly different in both the amount and sequence of repeats they harbor. We used sensitive repeat discovery and evolutionary reconstruction to show that the KNL1 repeat arrays have undergone extensive, often species-specific array reorganization through iterative cycles of higher order multiplication in conjunction with rapid sequence diversification. The number of repeats per array ranges from none in flowering plants up to approximately 35–40 in drosophilids. Remarkably, closely related drosophilid species have independently expanded specific repeats, indicating near complete array replacement after only approximately 25–40 Myr of evolution. We further show that repeat sequences were altered by the parallel emergence/loss of various short linear motifs, including phosphosites, which supplement the MELT-like motif, signifying modular repeat evolution. These observations point to widespread recurrent episodes of concerted KNL1 repeat evolution in all eukaryotic supergroups. We discuss our findings in the light of the conserved function of KNL1 repeats in localizing the BUB1–BUB3 dimer and its role in chromosome segregation.
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Affiliation(s)
- Eelco Tromer
- Molecular Cancer Research, University Medical Center Utrecht, The Netherlands Center for Molecular Medicine, University Medical Center Utrecht, The Netherlands Theoretical Biology and Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, The Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, The Netherlands
| | - Geert J P L Kops
- Molecular Cancer Research, University Medical Center Utrecht, The Netherlands Center for Molecular Medicine, University Medical Center Utrecht, The Netherlands Cancer Genomics Netherlands, University Medical Center Utrecht, The Netherlands
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83
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Aravamudhan P, Goldfarb AA, Joglekar AP. The kinetochore encodes a mechanical switch to disrupt spindle assembly checkpoint signalling. Nat Cell Biol 2015; 17:868-79. [PMID: 26053220 PMCID: PMC4630029 DOI: 10.1038/ncb3179] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 04/23/2015] [Indexed: 12/14/2022]
Abstract
The spindle assembly checkpoint (SAC) is a unique signalling mechanism that responds to the state of attachment of the kinetochore to spindle microtubules. SAC signalling is activated by unattached kinetochores, and it is silenced after these kinetochores form end-on microtubule attachments. Although the biochemical cascade of SAC signalling is well understood, how kinetochore-microtubule attachment disrupts it remained unknown. Here we show that, in budding yeast, end-on microtubule attachment to the kinetochore physically separates the Mps1 kinase, which probably binds to the calponin homology domain of Ndc80, from the kinetochore substrate of Mps1, Spc105 (KNL1 orthologue). This attachment-mediated separation disrupts the phosphorylation of Spc105, and enables SAC silencing. Additionally, the Dam1 complex may act as a barrier that shields Spc105 from Mps1. Together these data suggest that the protein architecture of the kinetochore encodes a mechanical switch. End-on microtubule attachment to the kinetochore turns this switch off to silence the SAC.
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Affiliation(s)
| | - Alan A. Goldfarb
- Cell and developmental biology, University of Michigan, 109 Zina Pitcher Place, 3067 BSRB, Ann Arbor, MI-48109, USA
| | - Ajit P. Joglekar
- Biophysics, University of Michigan, Ann Arbor, MI-48109, USA
- Cell and developmental biology, University of Michigan, 109 Zina Pitcher Place, 3067 BSRB, Ann Arbor, MI-48109, USA
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84
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Klare K, Weir JR, Basilico F, Zimniak T, Massimiliano L, Ludwigs N, Herzog F, Musacchio A. CENP-C is a blueprint for constitutive centromere-associated network assembly within human kinetochores. J Cell Biol 2015; 210:11-22. [PMID: 26124289 PMCID: PMC4494010 DOI: 10.1083/jcb.201412028] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 06/01/2015] [Indexed: 11/22/2022] Open
Abstract
CENP-C promotes kinetochore targeting of other constitutive centromere–associated network (CCAN) subunits by directly interacting with the four-subunit CCAN subcomplex CENP-HIKM and spatially organizing the localization of all other CCAN subunits downstream of CENP-A. Kinetochores are multisubunit complexes that assemble on centromeres to bind spindle microtubules and promote faithful chromosome segregation during cell division. A 16-subunit complex named the constitutive centromere–associated network (CCAN) creates the centromere–kinetochore interface. CENP-C, a CCAN subunit, is crucial for kinetochore assembly because it links centromeres with the microtubule-binding interface of kinetochores. The role of CENP-C in CCAN organization, on the other hand, had been incompletely understood. In this paper, we combined biochemical reconstitution and cellular investigations to unveil how CENP-C promotes kinetochore targeting of other CCAN subunits. The so-called PEST domain in the N-terminal half of CENP-C interacted directly with the four-subunit CCAN subcomplex CENP-HIKM. We identified crucial determinants of this interaction whose mutation prevented kinetochore localization of CENP-HIKM and of CENP-TW, another CCAN subcomplex. When considered together with previous observations, our data point to CENP-C as a blueprint for kinetochore assembly.
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Affiliation(s)
- Kerstin Klare
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - John R Weir
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Federica Basilico
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany Department of Experimental Oncology, European Institute of Oncology, 20139 Milan, Italy
| | - Tomasz Zimniak
- Gene Center Munich, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Lucia Massimiliano
- Department of Experimental Oncology, European Institute of Oncology, 20139 Milan, Italy
| | - Nina Ludwigs
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Franz Herzog
- Gene Center Munich, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45141 Essen, Germany
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85
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Zhang G, Lischetti T, Hayward DG, Nilsson J. Distinct domains in Bub1 localize RZZ and BubR1 to kinetochores to regulate the checkpoint. Nat Commun 2015; 6:7162. [PMID: 26031201 PMCID: PMC4458899 DOI: 10.1038/ncomms8162] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/10/2015] [Indexed: 12/29/2022] Open
Abstract
The spindle assembly checkpoint (SAC) ensures proper chromosome segregation by delaying anaphase onset in response to unattached kinetochores. Checkpoint signalling requires the kinetochore localization of the Mad1–Mad2 complex that in more complex eukaryotes depends on the Rod–Zwilch–ZW10 (RZZ) complex. The kinetochore protein Zwint has been proposed to be the kinetochore receptor for RZZ, but here we show that Bub1 and not Zwint is required for RZZ recruitment. We find that the middle region of Bub1 encompassing a domain essential for SAC signalling contributes to RZZ localization. In addition, we show that a distinct region in Bub1 mediates kinetochore localization of BubR1 through direct binding, but surprisingly removal of this region increases checkpoint strength. Our work thus uncovers how Bub1 coordinates checkpoint signalling by distinct domains for RZZ and BubR1 recruitment and suggests that Bub1 localizes antagonistic checkpoint activities. The spindle assembly checkpoint (SAC) depends on the recruitment of specific protein complexes to the kinetochore. Here Zhang et al. show that Bub1 recruits the RZZ complex and BubR1 to the kinetochore, and loss of the BubR1 binding sequence enhances checkpoint activity suggesting both SAC activating and silencing roles.
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Affiliation(s)
- Gang Zhang
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Tiziana Lischetti
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Daniel G Hayward
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Jakob Nilsson
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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86
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De la Fuente IM. Elements of the cellular metabolic structure. Front Mol Biosci 2015; 2:16. [PMID: 25988183 PMCID: PMC4428431 DOI: 10.3389/fmolb.2015.00016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/12/2015] [Indexed: 12/19/2022] Open
Abstract
A large number of studies have demonstrated the existence of metabolic covalent modifications in different molecular structures, which are able to store biochemical information that is not encoded by DNA. Some of these covalent mark patterns can be transmitted across generations (epigenetic changes). Recently, the emergence of Hopfield-like attractor dynamics has been observed in self-organized enzymatic networks, which have the capacity to store functional catalytic patterns that can be correctly recovered by specific input stimuli. Hopfield-like metabolic dynamics are stable and can be maintained as a long-term biochemical memory. In addition, specific molecular information can be transferred from the functional dynamics of the metabolic networks to the enzymatic activity involved in covalent post-translational modulation, so that determined functional memory can be embedded in multiple stable molecular marks. The metabolic dynamics governed by Hopfield-type attractors (functional processes), as well as the enzymatic covalent modifications of specific molecules (structural dynamic processes) seem to represent the two stages of the dynamical memory of cellular metabolism (metabolic memory). Epigenetic processes appear to be the structural manifestation of this cellular metabolic memory. Here, a new framework for molecular information storage in the cell is presented, which is characterized by two functionally and molecularly interrelated systems: a dynamic, flexible and adaptive system (metabolic memory) and an essentially conservative system (genetic memory). The molecular information of both systems seems to coordinate the physiological development of the whole cell.
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Affiliation(s)
- Ildefonso M. De la Fuente
- Department of Cell Biology and Immunology, Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones CientíficasGranada, Spain
- Department of Mathematics, University of the Basque Country, UPV/Euskal Herriko UnibertsitateaLeioa, Spain
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87
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Abstract
Robust but dynamic attachment between kinetochores and spindle microtubules is an essential prerequisite for accurate chromosome segregation and for preventing aneuploidy. A pair of recent studies has shed light on the details of how the molecular machinery that orchestrates these attachments is recruited to mitotic kinetochores.
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Affiliation(s)
- Sana Afreen
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Dileep Varma
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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88
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Kim S, Yu H. Multiple assembly mechanisms anchor the KMN spindle checkpoint platform at human mitotic kinetochores. ACTA ACUST UNITED AC 2015; 208:181-96. [PMID: 25601404 PMCID: PMC4298689 DOI: 10.1083/jcb.201407074] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During mitosis in human cells, separate mechanisms involving Aurora B and CENP-T promote anchoring of the microtubule- and checkpoint-receptor complex KMN at kinetochores. During mitosis, the spindle checkpoint senses kinetochores not properly attached to spindle microtubules and prevents precocious sister-chromatid separation and aneuploidy. The constitutive centromere-associated network (CCAN) at inner kinetochores anchors the KMN network consisting of Knl1, the Mis12 complex (Mis12C), and the Ndc80 complex (Ndc80C) at outer kinetochores. KMN is a critical kinetochore receptor for both microtubules and checkpoint proteins. Here, we show that nearly complete inactivation of KMN in human cells through multiple strategies produced strong checkpoint defects even when all kinetochores lacked microtubule attachment. These KMN-inactivating strategies reveal multiple KMN assembly mechanisms at human mitotic kinetochores. In one mechanism, the centromeric kinase Aurora B phosphorylates Mis12C and strengthens its binding to the CCAN subunit CENP-C. In another, CENP-T contributes to KMN attachment in a CENP-H-I-K–dependent manner. Our study provides insights into the mechanisms of mitosis-specific assembly of the checkpoint platform KMN at human kinetochores.
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Affiliation(s)
- Soonjoung Kim
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Hongtao Yu
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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89
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Ibrahim B. Toward a systems-level view of mitotic checkpoints. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 117:217-224. [DOI: 10.1016/j.pbiomolbio.2015.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 02/10/2015] [Accepted: 02/13/2015] [Indexed: 12/22/2022]
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90
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Distinct organization and regulation of the outer kinetochore KMN network downstream of CENP-C and CENP-T. Curr Biol 2015; 25:671-7. [PMID: 25660545 PMCID: PMC4348146 DOI: 10.1016/j.cub.2015.01.059] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 01/19/2015] [Accepted: 01/23/2015] [Indexed: 11/24/2022]
Abstract
The kinetochore provides a vital connection between chromosomes and spindle microtubules [1, 2]. Defining the molecular architecture of the core kinetochore components is critical for understanding the mechanisms by which the kinetochore directs chromosome segregation. The KNL1/Mis12 complex/Ndc80 complex (KMN) network acts as the primary microtubule binding interface at kinetochores [3], and provides a platform to recruit regulatory proteins [4]. Recent work found that the inner kinetochore components CENP-C and CENP-T act in parallel to recruit the KMN network to kinetochores [5-8]. However, due to the presence of these dual pathways, it has not been possible to distinguish differences in the nature of kinetochore assembly downstream of CENP-C or CENP-T. Here, we separated these pathways by targeting CENP-C and CENP-T independently to an ectopic chromosomal locus in human cells. Our work reveals that the organization of the KMN network components downstream of CENP-C and CENP-T is distinct. CENP-C recruits the Ndc80 complex through its interactions with KNL1 and the Mis12 complex. In contrast, CENP-T directly interacts with Ndc80, which in turn promotes KNL1/Mis12 complex recruitment through a separate region on CENP-T, resulting in functional relationships for KMN network localization that are inverted relative to the CENP-C pathway. We also find that distinct regulatory paradigms control the assembly of these pathways, with Aurora B kinase promoting KMN network recruitment to CENP-C, and cyclin-dependent kinase (CDK) regulating KMN network recruitment to CENP-T. This work reveals unexpected complexity for the architecture and regulation of the core components of the kinetochore-microtubule interface.
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91
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Vleugel M, Omerzu M, Groenewold V, Hadders MA, Lens SMA, Kops GJPL. Sequential multisite phospho-regulation of KNL1-BUB3 interfaces at mitotic kinetochores. Mol Cell 2015; 57:824-835. [PMID: 25661489 DOI: 10.1016/j.molcel.2014.12.036] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/08/2014] [Accepted: 12/22/2014] [Indexed: 12/21/2022]
Abstract
Regulated recruitment of the kinase-adaptor complex BUB1/BUB3 to kinetochores is crucial for correcting faulty chromosome-spindle attachments and for spindle assembly checkpoint (SAC) signaling. BUB1/BUB3 localizes to kinetochores by binding phosphorylated MELT motifs (MELpT) in the kinetochore scaffold KNL1. Human KNL1 has 19 repeats that contain a MELT-like sequence. The repeats are, however, larger than MELT, and repeat sequences can vary significantly. Using systematic screening, we show that only a limited number of repeats is "active." Repeat activity correlates with the presence of a vertebrate-specific SHT motif C-terminal to the MELT sequence. SHT motifs are phosphorylated by MPS1 in a manner that requires prior phosphorylation of MELT. Phospho-SHT (SHpT) synergizes with MELpT in BUB3/BUB1 binding in vitro and in cells, and human BUB3 mutated in a predicted SHpT-binding surface cannot localize to kinetochores. Our data show sequential multisite regulation of the KNL1-BUB1/BUB3 interaction and provide mechanistic insight into evolution of the KNL1-BUB3 interface.
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Affiliation(s)
- Mathijs Vleugel
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Manja Omerzu
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Department of Medical Oncology, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Vincent Groenewold
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Department of Medical Oncology, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Michael A Hadders
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Susanne M A Lens
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Geert J P L Kops
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Department of Medical Oncology, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands.
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92
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Tang NH, Toda T. MAPping the Ndc80 loop in cancer: A possible link between Ndc80/Hec1 overproduction and cancer formation. Bioessays 2015; 37:248-56. [PMID: 25557589 PMCID: PMC4359004 DOI: 10.1002/bies.201400175] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mis-regulation (e.g. overproduction) of the human Ndc80/Hec1 outer kinetochore protein has been associated with aneuploidy and tumourigenesis, but the genetic basis and underlying mechanisms of this phenomenon remain poorly understood. Recent studies have identified the ubiquitous Ndc80 internal loop as a protein-protein interaction platform. Binding partners include the Ska complex, the replication licensing factor Cdt1, the Dam1 complex, TACC-TOG microtubule-associated proteins (MAPs) and kinesin motors. We review the field and propose that the overproduction of Ndc80 may unfavourably absorb these interactors through the internal loop domain and lead to a change in the equilibrium of MAPs and motors in the cells. This sequestration will disrupt microtubule dynamics and the proper segregation of chromosomes in mitosis, leading to aneuploid formation. Further investigation of Ndc80 internal loop-MAPs interactions will bring new insights into their roles in kinetochore-microtubule attachment and tumourigenesis.
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Affiliation(s)
- Ngang Heok Tang
- Laboratory of Cell Regulation, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, London, UK
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93
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Kern DM, Kim T, Rigney M, Hattersley N, Desai A, Cheeseman IM. The outer kinetochore protein KNL-1 contains a defined oligomerization domain in nematodes. Mol Biol Cell 2014; 26:229-37. [PMID: 25411336 PMCID: PMC4294671 DOI: 10.1091/mbc.e14-06-1125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The kinetochore is a large, macromolecular assembly that is essential for connecting chromosomes to microtubules during mitosis. Despite the recent identification of multiple kinetochore components, the nature and organization of the higher-order kinetochore structure remain unknown. The outer kinetochore KNL-1/Mis12 complex/Ndc80 complex (KMN) network plays a key role in generating and sensing microtubule attachments. Here we demonstrate that Caenorhabditis elegans KNL-1 exists as an oligomer, and we identify a specific domain in KNL-1 responsible for this activity. An N-terminal KNL-1 domain from both C. elegans and the related nematode Caenorhabditis remanei oligomerizes into a decameric assembly that appears roughly circular when visualized by electron microscopy. On the basis of sequence and mutational analysis, we identify a small hydrophobic region as responsible for this oligomerization activity. However, mutants that precisely disrupt KNL-1 oligomerization did not alter KNL-1 localization or result in the loss of embryonic viability based on gene replacements in C. elegans. In C. elegans, KNL-1 oligomerization may coordinate with other kinetochore activities to ensure the proper organization, function, and sensory capabilities of the kinetochore-microtubule attachment.
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Affiliation(s)
- David M Kern
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Taekyung Kim
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093
| | - Mike Rigney
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02454
| | - Neil Hattersley
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093
| | - Arshad Desai
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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94
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Abstract
In eukaryotic cell division, the kinetochore mediates chromosome attachment to spindle microtubules and acts as a scaffold for signaling pathways, ensuring the accuracy of chromosome segregation. The architecture of the kinetochore underlies its function in mitosis. In this issue, Hornung et al. (2014. J. Cell Biol.http://dx.doi.org/201403081) identify an unexpected linkage between the inner and outer regions of the kinetochore in budding yeast that suggests a new model for the construction of this interface.
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Affiliation(s)
- Kevin D Corbett
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Arshad Desai
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
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95
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Hornung P, Troc P, Malvezzi F, Maier M, Demianova Z, Zimniak T, Litos G, Lampert F, Schleiffer A, Brunner M, Mechtler K, Herzog F, Marlovits TC, Westermann S. A cooperative mechanism drives budding yeast kinetochore assembly downstream of CENP-A. ACTA ACUST UNITED AC 2014; 206:509-24. [PMID: 25135934 PMCID: PMC4137059 DOI: 10.1083/jcb.201403081] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During kinetochore assembly in budding yeast, the key steps of CENP-A recognition and outer kinetochore recruitment are executed through different yeast CCAN subunits, potentially protecting against inappropriate kinetochore assembly. Kinetochores are megadalton-sized protein complexes that mediate chromosome–microtubule interactions in eukaryotes. How kinetochore assembly is triggered specifically on centromeric chromatin is poorly understood. Here we use biochemical reconstitution experiments alongside genetic and structural analysis to delineate the contributions of centromere-associated proteins to kinetochore assembly in yeast. We show that the conserved kinetochore subunits Ame1CENP-U and Okp1CENP-Q form a DNA-binding complex that associates with the microtubule-binding KMN network via a short Mtw1 recruitment motif in the N terminus of Ame1. Point mutations in the Ame1 motif disrupt kinetochore function by preventing KMN assembly on chromatin. Ame1–Okp1 directly associates with the centromere protein C (CENP-C) homologue Mif2 to form a cooperative binding platform for outer kinetochore assembly. Our results indicate that the key assembly steps, CENP-A recognition and outer kinetochore recruitment, are executed through different yeast constitutive centromere-associated network subunits. This two-step mechanism may protect against inappropriate kinetochore assembly similar to rate-limiting nucleation steps used by cytoskeletal polymers.
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Affiliation(s)
- Peter Hornung
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Paulina Troc
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Francesca Malvezzi
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Michael Maier
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Zuzana Demianova
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Tomasz Zimniak
- Department of Biochemistry, Gene Center, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Gabriele Litos
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Fabienne Lampert
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria Institute of Molecular Biotechnology GmbH, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Matthias Brunner
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria Institute of Molecular Biotechnology GmbH, Austrian Academy of Sciences, 1030 Vienna, Austria Center for Structural Systems Biology, University Medical Center Eppendorf-Hamburg, 20246 Hamburg, Germany Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Karl Mechtler
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Franz Herzog
- Department of Biochemistry, Gene Center, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Thomas C Marlovits
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria Institute of Molecular Biotechnology GmbH, Austrian Academy of Sciences, 1030 Vienna, Austria Center for Structural Systems Biology, University Medical Center Eppendorf-Hamburg, 20246 Hamburg, Germany Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Stefan Westermann
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
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96
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Lee S, Bolanos-Garcia VM. The dynamics of signal amplification by macromolecular assemblies for the control of chromosome segregation. Front Physiol 2014; 5:368. [PMID: 25324779 PMCID: PMC4179342 DOI: 10.3389/fphys.2014.00368] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/07/2014] [Indexed: 11/13/2022] Open
Abstract
The control of chromosome segregation relies on the spindle assembly checkpoint (SAC), a complex regulatory system that ensures the high fidelity of chromosome segregation in higher organisms by delaying the onset of anaphase until each chromosome is properly bi-oriented on the mitotic spindle. Central to this process is the establishment of multiple yet specific protein-protein interactions in a narrow time-space window. Here we discuss the highly dynamic nature of multi-protein complexes that control chromosome segregation in which an intricate network of weak but cooperative interactions modulate signal amplification to ensure a proper SAC response. We also discuss the current structural understanding of the communication between the SAC and the kinetochore; how transient interactions can regulate the assembly and disassembly of the SAC as well as the challenges and opportunities for the definition and the manipulation of the flow of information in SAC signaling.
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Affiliation(s)
- Semin Lee
- Center for Biomedical Informatics, Harvard Medical School, Harvard University Boston, MA, USA
| | - Victor M Bolanos-Garcia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University Oxford, UK
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97
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Sacristan C, Kops GJPL. Joined at the hip: kinetochores, microtubules, and spindle assembly checkpoint signaling. Trends Cell Biol 2014; 25:21-8. [PMID: 25220181 DOI: 10.1016/j.tcb.2014.08.006] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 01/01/2023]
Abstract
Error-free chromosome segregation relies on stable connections between kinetochores and spindle microtubules. The spindle assembly checkpoint (SAC) monitors such connections and relays their absence to the cell cycle machinery to delay cell division. The molecular network at kinetochores that is responsible for microtubule binding is integrated with the core components of the SAC signaling system. Molecular-mechanistic understanding of how the SAC is coupled to the kinetochore-microtubule interface has advanced significantly in recent years. The latest insights not only provide a striking view of the dynamics and regulation of SAC signaling events at the outer kinetochore but also create a framework for understanding how that signaling may be terminated when kinetochores and microtubules connect.
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Affiliation(s)
- Carlos Sacristan
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Geert J P L Kops
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands.
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98
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Ghongane P, Kapanidou M, Asghar A, Elowe S, Bolanos-Garcia VM. The dynamic protein Knl1 - a kinetochore rendezvous. J Cell Sci 2014; 127:3415-23. [PMID: 25052095 DOI: 10.1242/jcs.149922] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Knl1 (also known as CASC5, UniProt Q8NG31) is an evolutionarily conserved scaffolding protein that is required for proper kinetochore assembly, spindle assembly checkpoint (SAC) function and chromosome congression. A number of recent reports have confirmed the prominence of Knl1 in these processes and provided molecular details and structural features that dictate Knl1 functions in higher organisms. Knl1 recruits SAC components to the kinetochore and is the substrate of certain protein kinases and phosphatases, the interplay of which ensures the exquisite regulation of the aforementioned processes. In this Commentary, we discuss the overall domain organization of Knl1 and the roles of this protein as a versatile docking platform. We present emerging roles of the protein interaction motifs present in Knl1, including the RVSF, SILK, MELT and KI motifs, and their role in the recruitment and regulation of the SAC proteins Bub1, BubR1, Bub3 and Aurora B. Finally, we explore how the regions of low structural complexity that characterize Knl1 are implicated in the cooperative interactions that mediate binding partner recognition and scaffolding activity by Knl1.
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Affiliation(s)
- Priyanka Ghongane
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Maria Kapanidou
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Adeel Asghar
- Reproduction, Perinatal Health and Child Health, Centre de Recherche du CHUQ, 2705, Boulevard Laurier, T3-51, Québec, QC G1V 4G2, Canada
| | - Sabine Elowe
- Reproduction, Perinatal Health and Child Health, Centre de Recherche du CHUQ, 2705, Boulevard Laurier, T3-51, Québec, QC G1V 4G2, Canada
| | - Victor M Bolanos-Garcia
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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99
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Basilico F, Maffini S, Weir JR, Prumbaum D, Rojas AM, Zimniak T, De Antoni A, Jeganathan S, Voss B, van Gerwen S, Krenn V, Massimiliano L, Valencia A, Vetter IR, Herzog F, Raunser S, Pasqualato S, Musacchio A. The pseudo GTPase CENP-M drives human kinetochore assembly. eLife 2014; 3:e02978. [PMID: 25006165 PMCID: PMC4080450 DOI: 10.7554/elife.02978] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Kinetochores, multi-subunit complexes that assemble at the interface with centromeres, bind spindle microtubules to ensure faithful delivery of chromosomes during cell division. The configuration and function of the kinetochore-centromere interface is poorly understood. We report that a protein at this interface, CENP-M, is structurally and evolutionarily related to small GTPases but is incapable of GTP-binding and conformational switching. We show that CENP-M is crucially required for the assembly and stability of a tetramer also comprising CENP-I, CENP-H, and CENP-K, the HIKM complex, which we extensively characterize through a combination of structural, biochemical, and cell biological approaches. A point mutant affecting the CENP-M/CENP-I interaction hampers kinetochore assembly and chromosome alignment and prevents kinetochore recruitment of the CENP-T/W complex, questioning a role of CENP-T/W as founder of an independent axis of kinetochore assembly. Our studies identify a single pathway having CENP-C as founder, and CENP-H/I/K/M and CENP-T/W as CENP-C-dependent followers.DOI: http://dx.doi.org/10.7554/eLife.02978.001.
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Affiliation(s)
- Federica Basilico
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - John R Weir
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Daniel Prumbaum
- Department of Physical Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Ana M Rojas
- Computational Biology and Bioinformatics Group, Institute of Biomedicine of Seville, Campus Hospital Universitario Virgen del Rocio, Seville, Spain
| | - Tomasz Zimniak
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-Universität, München, Munich, Germany
| | - Anna De Antoni
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Sadasivam Jeganathan
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Beate Voss
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Suzan van Gerwen
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Veronica Krenn
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Lucia Massimiliano
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Alfonso Valencia
- Structural Biology and Biocomputing Programme, Spanish National Cancer Centre-CNIO, Madrid, Spain
| | - Ingrid R Vetter
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Franz Herzog
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-Universität, München, Munich, Germany
| | - Stefan Raunser
- Department of Physical Biochemistry, 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 of Duisburg-Essen, Essen, Germany
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100
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Aravamudhan P, Felzer-Kim I, Gurunathan K, Joglekar AP. Assembling the protein architecture of the budding yeast kinetochore-microtubule attachment using FRET. Curr Biol 2014; 24:1437-46. [PMID: 24930965 PMCID: PMC4320969 DOI: 10.1016/j.cub.2014.05.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 04/20/2014] [Accepted: 05/06/2014] [Indexed: 11/20/2022]
Abstract
BACKGROUND The kinetochore is a multiprotein machine that couples chromosome movement to microtubule (MT) polymerization and depolymerization. It uses numerous copies of at least three MT-binding proteins to generate bidirectional movement. The nanoscale organization of these proteins within the kinetochore plays an important role in shaping the mechanisms that drive persistent, bidirectional movement of the kinetochore. RESULTS We used fluorescence resonance energy transfer (FRET) between genetically encoded fluorescent proteins fused to kinetochore subunits to reconstruct the nanoscale organization of the budding yeast kinetochore. We performed >60 FRET and high-resolution colocalization measurements involving the essential MT-binding kinetochore components: Ndc80, Dam1, Spc105, and Stu2. These measurements reveal that neighboring Ndc80 complexes within the kinetochore are narrowly distributed along the length of the MT. Dam1 complex molecules are concentrated near the MT-binding domains of Ndc80. Stu2 localizes in high abundance within a narrowly defined territory within the kinetochore centered ∼20 nm on the centromeric side of the Dam1 complex. CONCLUSIONS Our data show that the MT attachment site of the budding yeast kinetochore is well organized. Ndc80, Dam1, and Stu2 are all narrowly distributed about their average positions along the kinetochore-MT axis. The relative organization of these components, their narrow distributions, and their known MT-binding properties together elucidate how their combined actions generate persistent, bidirectional kinetochore movement coupled to MT polymerization and depolymerization.
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Affiliation(s)
- Pavithra Aravamudhan
- Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA
| | - Isabella Felzer-Kim
- Cell and Developmental Biology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Kaushik Gurunathan
- Sastra University, Tirumalaisamudram, Thanjavur, Tamil Nadu 613402, India
| | - Ajit P Joglekar
- Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA; Cell and Developmental Biology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA.
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