1
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Walsh ME, King GA, Ünal E. Not just binary: embracing the complexity of nuclear division dynamics. Nucleus 2024; 15:2360601. [PMID: 38842147 PMCID: PMC11164224 DOI: 10.1080/19491034.2024.2360601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/22/2024] [Indexed: 06/07/2024] Open
Abstract
Cell division presents a challenge for eukaryotic cells: how can chromosomes effectively segregate within the confines of a membranous nuclear compartment? Different organisms have evolved diverse solutions by modulating the degree of nuclear compartmentalization, ranging from complete nuclear envelope breakdown to complete maintenance of nuclear compartmentalization via nuclear envelope expansion. Many intermediate forms exist between these extremes, suggesting that nuclear dynamics during cell division are surprisingly plastic. In this review, we highlight the evolutionary diversity of nuclear divisions, focusing on two defining characteristics: (1) chromosome compartmentalization and (2) nucleocytoplasmic transport. Further, we highlight recent evidence that nuclear behavior during division can vary within different cellular contexts in the same organism. The variation observed within and between organisms underscores the dynamic evolution of nuclear divisions tailored to specific contexts and cellular requirements. In-depth investigation of diverse nuclear divisions will enhance our understanding of the nucleus, both in physiological and pathological states.
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Affiliation(s)
- Madison E. Walsh
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
| | - Grant A. King
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
| | - Elçin Ünal
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
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2
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Chen JS, Igarashi MG, Ren L, Hanna SM, Turner LA, McDonald NA, Beckley JR, Willet AH, Gould KL. The core spindle pole body scaffold Ppc89 links the pericentrin orthologue Pcp1 to the fission yeast spindle pole body via an evolutionarily conserved interface. Mol Biol Cell 2024; 35:ar112. [PMID: 38985524 DOI: 10.1091/mbc.e24-05-0220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024] Open
Abstract
Centrosomes and spindle pole bodies (SPBs) are important for mitotic spindle formation and serve as cellular signaling platforms. Although centrosomes and SPBs differ in morphology, many mechanistic insights into centrosome function have been gleaned from SPB studies. In the fission yeast Schizosaccharomyces pombe, the α-helical protein Ppc89, identified based on its interaction with the septation initiation network scaffold Sid4, comprises the SPB core. High-resolution imaging has suggested that SPB proteins assemble on the Ppc89 core during SPB duplication, but such interactions are undefined. Here, we define a connection between Ppc89 and the essential pericentrin Pcp1. Specifically, we found that a predicted third helix within Ppc89 binds the Pcp1 pericentrin-AKAP450 centrosomal targeting (PACT) domain complexed with calmodulin. Ppc89 helix 3 contains similarity to present in the N-terminus of Cep57 (PINC) motifs found in the centrosomal proteins fly SAS-6 and human Cep57 and also to the S. cerevisiae SPB protein Spc42. These motifs bind pericentrin-calmodulin complexes and AlphaFold2 models suggest a homologous complex assembles in all four organisms. Mutational analysis of the S. pombe complex supports the importance of Ppc89-Pcp1 binding interface in vivo. Our studies provide insight into the core architecture of the S. pombe SPB and suggest an evolutionarily conserved mechanism of scaffolding pericentrin-calmodulin complexes for mitotic spindle formation.
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Affiliation(s)
- Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Maya G Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Sarah M Hanna
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Lesley A Turner
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Janel R Beckley
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
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3
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Zemlianski V, Marešová A, Princová J, Holič R, Häsler R, Ramos Del Río MJ, Lhoste L, Zarechyntsava M, Převorovský M. Nitrogen availability is important for preventing catastrophic mitosis in fission yeast. J Cell Sci 2024; 137:jcs262196. [PMID: 38780300 DOI: 10.1242/jcs.262196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 05/16/2024] [Indexed: 05/25/2024] Open
Abstract
Mitosis is a crucial stage in the cell cycle, controlled by a vast network of regulators responding to multiple internal and external factors. The fission yeast Schizosaccharomyces pombe demonstrates catastrophic mitotic phenotypes due to mutations or drug treatments. One of the factors provoking catastrophic mitosis is a disturbed lipid metabolism, resulting from, for example, mutations in the acetyl-CoA/biotin carboxylase (cut6), fatty acid synthase (fas2, also known as lsd1) or transcriptional regulator of lipid metabolism (cbf11) genes, as well as treatment with inhibitors of fatty acid synthesis. It has been previously shown that mitotic fidelity in lipid metabolism mutants can be partially rescued by ammonium chloride supplementation. In this study, we demonstrate that mitotic fidelity can be improved by multiple nitrogen sources. Moreover, this improvement is not limited to lipid metabolism disturbances but also applies to a number of unrelated mitotic mutants. Interestingly, the partial rescue is not achieved by restoring the lipid metabolism state, but rather indirectly. Our results highlight a novel role for nitrogen availability in mitotic fidelity.
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Affiliation(s)
- Viacheslav Zemlianski
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Anna Marešová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Jarmila Princová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Roman Holič
- Centre of Biosciences SAS, Institute of Animal Biochemistry and Genetics, Dúbravská cesta 9, 840 05 Bratislava, Slovak Republic
| | - Robert Häsler
- Center for Inflammatory Skin Diseases, Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Campus Kiel, Rosalind-Franklin-Straße 9, 24105 Kiel, Germany
| | - Manuel José Ramos Del Río
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Laurane Lhoste
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Maryia Zarechyntsava
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
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4
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Ader NR, Chen L, Surovtsev IV, Chadwick WL, Rodriguez EC, King MC, Lusk CP. An ESCRT grommet cooperates with a diffusion barrier to maintain nuclear integrity. Nat Cell Biol 2023; 25:1465-1477. [PMID: 37783794 DOI: 10.1038/s41556-023-01235-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 08/17/2023] [Indexed: 10/04/2023]
Abstract
The molecular mechanisms by which the endosomal sorting complexes required for transport (ESCRT) proteins contribute to the integrity of the nuclear envelope (NE) barrier are not fully defined. We leveraged the single NE hole generated by mitotic extrusion of the Schizosaccharomyces pombe spindle pole body to reveal two modes of ESCRT function executed by distinct complements of ESCRT-III proteins, both dependent on CHMP7/Cmp7. A grommet-like function is required to restrict the NE hole in anaphase B, whereas replacement of Cmp7 by a sealing module ultimately closes the NE in interphase. Without Cmp7, nucleocytoplasmic compartmentalization remains intact despite NE discontinuities of up to 540 nm, suggesting mechanisms to limit diffusion through these holes. We implicate spindle pole body proteins as key components of a diffusion barrier acting with Cmp7 in anaphase B. Thus, NE remodelling mechanisms cooperate with proteinaceous diffusion barriers beyond nuclear pore complexes to maintain the nuclear compartment.
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Affiliation(s)
- Nicholas R Ader
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Linda Chen
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Ivan V Surovtsev
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Physics, Yale University, New Haven, CT, USA
| | | | - Elisa C Rodriguez
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Megan C King
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA.
- Department of Molecular, Cell and Developmental Biology, Yale University, New Haven, CT, USA.
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA.
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5
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Willet AH, Wos M, Igarashi MG, Ren L, Turner LA, Gould KL. Elevated levels of sphingolipid MIPC in the plasma membrane disrupt the coordination of cell growth with cell wall formation in fission yeast. PLoS Genet 2023; 19:e1010987. [PMID: 37792890 PMCID: PMC10578601 DOI: 10.1371/journal.pgen.1010987] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/16/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023] Open
Abstract
Coupling cell wall expansion with cell growth is a universal challenge faced by walled organisms. Mutations in Schizosaccharomyces pombe css1, which encodes a PM inositol phosphosphingolipid phospholipase C, prevent cell wall expansion but not synthesis of cell wall material. To probe how Css1 modulates cell wall formation we used classical and chemical genetics coupled with quantitative mass spectrometry. We found that elevated levels of the sphingolipid biosynthetic pathway's final product, mannosylinositol phosphorylceramide (MIPC), specifically correlated with the css1-3 phenotype. We also found that an apparent indicator of sphingolipids and a sterol biosensor accumulated at the cytosolic face of the PM at cell tips and the division site of css1-3 cells and, in accord, the PM in css1-3 was less dynamic than in wildtype cells. Interestingly, disrupting the protein glycosylation machinery recapitulated the css1-3 phenotype and led us to investigate Ghs2, a glycosylated PM protein predicted to modify cell wall material. Disrupting Ghs2 function led to aberrant cell wall material accumulation suggesting Ghs2 is dysfunctional in css1-3. We conclude that preventing an excess of MIPC in the S. pombe PM is critical to the function of key PM-localized proteins necessary for coupling growth with cell wall formation.
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Affiliation(s)
- Alaina H. Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Marcin Wos
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Maya G. Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Lesley A. Turner
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
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6
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Takasaki T, Obana R, Fujiwara D, Tomimoto N, Khandakar GI, Satoh R, Sugiura R. ACA-28, an anticancer compound, induces Pap1 nuclear accumulation via ROS-dependent and -independent mechanisms in fission yeast. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000711. [PMID: 37720683 PMCID: PMC10502506 DOI: 10.17912/micropub.biology.000711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 08/08/2023] [Accepted: 08/28/2023] [Indexed: 09/19/2023]
Abstract
The nucleocytoplasmic transport of proteins is an important mechanism to control cell fate. Pap1 is a fission yeast nucleocytoplasmic shuttling transcription factor of which localization is redox regulated. The nuclear export factor Crm1/exportin negatively regulates Pap1 by exporting it from the nucleus to the cytoplasm. Here, we describe the effect of an anti-cancer compound ACA-28, an improved derivative of 1'-acetoxychavicol acetate (ACA), on the subcellular distribution of Pap1. ACA-28 induced nuclear accumulation of Pap1 more strongly than did ACA. ROS inhibitor N-acetyl-L-cysteine (NAC) partly antagonized the Pap1 nuclear accumulation induced by ACA-28. NAC almost abolished Pap1 nuclear localization upon H 2 O 2 , whereas leptomycin B (LMB)-mediated inhibition of Pap1 nuclear export was resistant to NAC. Collectively, ACA-28-mediated apoptosis in cancer cells may involve ROS-dependent and -independent mechanisms.
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Affiliation(s)
- Teruaki Takasaki
- Faculty of Pharmacy, Kindai University, Higashiosaka, Osaka, Japan
| | - Reo Obana
- Faculty of Pharmacy, Kindai University, Higashiosaka, Osaka, Japan
| | - Daiki Fujiwara
- Faculty of Pharmacy, Kindai University, Higashiosaka, Osaka, Japan
| | - Naofumi Tomimoto
- Faculty of Pharmacy, Kindai University, Higashiosaka, Osaka, Japan
| | | | - Ryosuke Satoh
- Faculty of Pharmacy, Kindai University, Higashiosaka, Osaka, Japan
| | - Reiko Sugiura
- Faculty of Pharmacy, Kindai University, Higashiosaka, Osaka, Japan
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7
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Amm I, Weberruss M, Hellwig A, Schwarz J, Tatarek-Nossol M, Lüchtenborg C, Kallas M, Brügger B, Hurt E, Antonin W. Distinct domains in Ndc1 mediate its interaction with the Nup84 complex and the nuclear membrane. J Cell Biol 2023; 222:e202210059. [PMID: 37154843 PMCID: PMC10165475 DOI: 10.1083/jcb.202210059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 01/31/2023] [Accepted: 03/17/2023] [Indexed: 05/10/2023] Open
Abstract
Nuclear pore complexes (NPCs) are embedded in the nuclear envelope and built from ∼30 different nucleoporins (Nups) in multiple copies, few are integral membrane proteins. One of these transmembrane nucleoporins, Ndc1, is thought to function in NPC assembly at the fused inner and outer nuclear membranes. Here, we show a direct interaction of Ndc1's transmembrane domain with Nup120 and Nup133, members of the pore membrane coating Y-complex. We identify an amphipathic helix in Ndc1's C-terminal domain binding highly curved liposomes. Upon overexpression, this amphipathic motif is toxic and dramatically alters the intracellular membrane organization in yeast. Ndc1's amphipathic motif functionally interacts with related motifs in the C-terminus of the nucleoporins Nup53 and Nup59, important for pore membrane binding and interconnecting NPC modules. The essential function of Ndc1 can be suppressed by deleting the amphipathic helix from Nup53. Our data indicate that nuclear membrane and presumably NPC biogenesis depends on a balanced ratio between amphipathic motifs in diverse nucleoporins.
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Affiliation(s)
- Ingo Amm
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Marion Weberruss
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Andrea Hellwig
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Johannes Schwarz
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Marianna Tatarek-Nossol
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Christian Lüchtenborg
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Martina Kallas
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Britta Brügger
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Ed Hurt
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
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8
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Gergely ZR, Ansari S, Jones MH, Zhou B, Cash C, McIntosh R, Betterton MD. The kinesin-5 protein Cut7 moves bidirectionally on fission yeast spindles with activity that increases in anaphase. J Cell Sci 2023; 136:jcs260474. [PMID: 36655493 PMCID: PMC10112985 DOI: 10.1242/jcs.260474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 01/10/2023] [Indexed: 01/20/2023] Open
Abstract
Kinesin-5 motors are essential to separate mitotic spindle poles and assemble a bipolar spindle in many organisms. These motors crosslink and slide apart antiparallel microtubules via microtubule plus-end-directed motility. However, kinesin-5 localization is enhanced away from antiparallel overlaps. Increasing evidence suggests this localization occurs due to bidirectional motility or trafficking. The purified fission-yeast kinesin-5 protein Cut7 moves bidirectionally, but bidirectionality has not been shown in cells, and the function of the minus-end-directed movement is unknown. Here, we characterized the motility of Cut7 on bipolar and monopolar spindles and observed movement toward both plus- and minus-ends of microtubules. Notably, the activity of the motor increased at anaphase B onset. Perturbations to microtubule dynamics only modestly changed Cut7 movement, whereas Cut7 mutation reduced movement. These results suggest that the directed motility of Cut7 contributes to the movement of the motor. Comparison of the Cut7 mutant and human Eg5 (also known as KIF11) localization suggest a new hypothesis for the function of minus-end-directed motility and spindle-pole localization of kinesin-5s.
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Affiliation(s)
- Zachary R. Gergely
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Saad Ansari
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Michele H. Jones
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Bojun Zhou
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Cai Cash
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Meredith D. Betterton
- Department of Physics, University of Colorado Boulder, Boulder, CO 80305, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80305, USA
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
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9
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Abstract
SignificanceMitosis is an essential process in all eukaryotes, but paradoxically, genes required for mitosis vary among species. The essentiality of many mitotic genes was bypassed by activating alternative mechanisms during evolution. However, bypass events have rarely been recapitulated experimentally. Here, using the fission yeast Schizosaccharomyces pombe, the essentiality of a kinase (Plo1) required for bipolar spindle formation was bypassed by other mutations, many of which are associated with glucose metabolism. The Plo1 bypass by the reduction in glucose uptake was dependent on another kinase (casein kinase I), which potentiated spindle microtubule formation. This study illustrates a rare experimental bypass of essentiality for mitotic genes and provides insights into the molecular diversity of mitosis.
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10
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Mitic K, Grafe M, Batsios P, Meyer I. Partial Disassembly of the Nuclear Pore Complex Proteins during Semi-Closed Mitosis in Dictyostelium discoideum. Cells 2022; 11:cells11030407. [PMID: 35159217 PMCID: PMC8834467 DOI: 10.3390/cells11030407] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 01/27/2023] Open
Abstract
Dictyostelium cells undergo a semi-closed mitosis, during which the nuclear envelope (NE) persists; however, free diffusion between the cytoplasm and the nucleus takes place. To permit the formation of the mitotic spindle, the nuclear envelope must be permeabilized in order to allow diffusion of tubulin dimers and spindle assembly factors into the nucleus. In Aspergillus, free diffusion of proteins between the cytoplasm and the nucleus is achieved by a partial disassembly of the nuclear pore complexes (NPCs) prior to spindle assembly. In order to determine whether this is also the case in Dictyostelium, we analysed components of the NPC by immunofluorescence microscopy and live cell imaging and studied their behaviour during interphase and mitosis. We observed that the NPCs are absent from the contact area of the nucleoli and that some nucleoporins also localize to the centrosome and the spindle poles. In addition, we could show that, during mitosis, the central FG protein NUP62, two inner ring components and Gle1 depart from the NPCs, while all other tested NUPs remained at the NE. This leads to the conclusion that indeed a partial disassembly of the NPCs takes place, which contributes to permeabilisation of the NE during semi-closed mitosis.
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11
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Zareiesfandabadi P, Elting MW. Force by minus-end motors Dhc1 and Klp2 collapses the S. pombe spindle after laser ablation. Biophys J 2022; 121:263-276. [PMID: 34951983 PMCID: PMC8790213 DOI: 10.1016/j.bpj.2021.12.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 11/19/2021] [Accepted: 12/16/2021] [Indexed: 01/21/2023] Open
Abstract
A microtubule-based machine called the mitotic spindle segregates chromosomes when eukaryotic cells divide. In the fission yeast Schizosaccharomyces pombe, which undergoes closed mitosis, the spindle forms a single bundle of microtubules inside the nucleus. During elongation, the spindle extends via antiparallel microtubule sliding by molecular motors. These extensile forces from the spindle are thought to resist compressive forces from the nucleus. We probe the mechanism and maintenance of this force balance via laser ablation of spindles at various stages of mitosis. We find that spindle pole bodies collapse toward each other after ablation, but spindle geometry is often rescued, allowing spindles to resume elongation. Although this basic behavior has been previously observed, many questions remain about the phenomenon's dynamics, mechanics, and molecular requirements. In this work, we find that previously hypothesized viscoelastic relaxation of the nucleus cannot explain spindle shortening in response to laser ablation. Instead, spindle collapse requires microtubule dynamics and is powered by the minus-end-directed motor proteins dynein Dhc1 and kinesin-14 Klp2, but it does not require the minus-end-directed kinesin Pkl1.
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Affiliation(s)
| | - Mary Williard Elting
- Department of Physics, North Carolina State University, Raleigh, North Carolina,Cluster for Quantitative and Computational Developmental Biology, North Carolina State University, Raleigh, North Carolina,Corresponding author
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12
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Evolution and diversification of the nuclear pore complex. Biochem Soc Trans 2021; 49:1601-1619. [PMID: 34282823 PMCID: PMC8421043 DOI: 10.1042/bst20200570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/21/2022]
Abstract
The nuclear pore complex (NPC) is responsible for transport between the cytoplasm and nucleoplasm and one of the more intricate structures of eukaryotic cells. Typically composed of over 300 polypeptides, the NPC shares evolutionary origins with endo-membrane and intraflagellar transport system complexes. The modern NPC was fully established by the time of the last eukaryotic common ancestor and, hence, prior to eukaryote diversification. Despite the complexity, the NPC structure is surprisingly flexible with considerable variation between lineages. Here, we review diversification of the NPC in major taxa in view of recent advances in genomic and structural characterisation of plant, protist and nucleomorph NPCs and discuss the implications for NPC evolution. Furthermore, we highlight these changes in the context of mRNA export and consider how this process may have influenced NPC diversity. We reveal the NPC as a platform for continual evolution and adaptation.
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13
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Bestul AJ, Yu Z, Unruh JR, Jaspersen SL. Redistribution of centrosomal proteins by centromeres and Polo kinase controls partial nuclear envelope breakdown in fission yeast. Mol Biol Cell 2021; 32:1487-1500. [PMID: 34133218 PMCID: PMC8351742 DOI: 10.1091/mbc.e21-05-0239] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Proper mitotic progression in Schizosaccharomyces pombe requires partial nuclear envelope breakdown (NEBD) and insertion of the spindle pole body (SPB—yeast centrosome) to build the mitotic spindle. Linkage of the centromere to the SPB is vital to this process, but why that linkage is important is not well understood. Utilizing high-resolution structured illumination microscopy, we show that the conserved Sad1-UNC-84 homology-domain protein Sad1 and other SPB proteins redistribute during mitosis to form a ring complex around SPBs, which is a precursor for localized NEBD and spindle formation. Although the Polo kinase Plo1 is not necessary for Sad1 redistribution, it localizes to the SPB region connected to the centromere, and its activity is vital for redistribution of other SPB ring proteins and for complete NEBD at the SPB to allow for SPB insertion. Our results lead to a model in which centromere linkage to the SPB drives redistribution of Sad1 and Plo1 activation that in turn facilitate partial NEBD and spindle formation through building of a SPB ring structure.
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Affiliation(s)
- Andrew J Bestul
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Zulin Yu
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO 64110.,Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160
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14
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Bustamante-Jaramillo LF, Ramos C, Martín-Castellanos C. The Meiosis-Specific Crs1 Cyclin Is Required for Efficient S-Phase Progression and Stable Nuclear Architecture. Int J Mol Sci 2021; 22:ijms22115483. [PMID: 34067465 PMCID: PMC8196990 DOI: 10.3390/ijms22115483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/13/2021] [Accepted: 05/19/2021] [Indexed: 11/26/2022] Open
Abstract
Cyclins and CDKs (Cyclin Dependent Kinases) are key players in the biology of eukaryotic cells, representing hubs for the orchestration of physiological conditions with cell cycle progression. Furthermore, as in the case of meiosis, cyclins and CDKs have acquired novel functions unrelated to this primal role in driving the division cycle. Meiosis is a specialized developmental program that ensures proper propagation of the genetic information to the next generation by the production of gametes with accurate chromosome content, and meiosis-specific cyclins are widespread in evolution. We have explored the diversification of CDK functions studying the meiosis-specific Crs1 cyclin in fission yeast. In addition to the reported role in DSB (Double Strand Break) formation, this cyclin is required for meiotic S-phase progression, a canonical role, and to maintain the architecture of the meiotic chromosomes. Crs1 localizes at the SPB (Spindle Pole Body) and is required to stabilize the cluster of telomeres at this location (bouquet configuration), as well as for normal SPB motion. In addition, Crs1 exhibits CDK(Cdc2)-dependent kinase activity in a biphasic manner during meiosis, in contrast to a single wave of protein expression, suggesting a post-translational control of its activity. Thus, Crs1 displays multiple functions, acting both in cell cycle progression and in several key meiosis-specific events.
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15
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Yukawa M, Teratani Y, Toda T. Escape from mitotic catastrophe by actin-dependent nuclear displacement in fission yeast. iScience 2021; 24:102031. [PMID: 33506191 PMCID: PMC7814194 DOI: 10.1016/j.isci.2020.102031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 11/23/2022] Open
Abstract
Eukaryotic cells position the nucleus within the proper intracellular space, thereby safeguarding a variety of cellular processes. In fission yeast, the interphase nucleus is placed in the cell middle in a microtubule-dependent manner. By contrast, how the mitotic nucleus is positioned remains elusive. Here we show that several cell-cycle mutants that arrest in mitosis all displace the nucleus toward one end of the cell. Intriguingly, the actin cytoskeleton is responsible for nuclear movement. Time-lapse live imaging indicates that mitosis-specific F-actin cables possibly push the nucleus through direct interaction with the nuclear envelope, and subsequently actomyosin ring constriction further shifts the nucleus away from the center. This nuclear movement is beneficial, because if the nuclei were retained in the center, unseparated chromosomes would be intersected by the contractile actin ring and the septum, imposing the lethal cut phenotype. Thus, fission yeast escapes from mitotic catastrophe by means of actin-dependent nuclear movement. Actin-dependent mitotic nuclear positioning in fission yeast Actin cables and ring closure drive nuclear displacement upon mitotic arrest Nuclear displacement evades cut-mediated cell death Survivors resume cell division as diploids
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Affiliation(s)
- Masashi Yukawa
- Hiroshima Research Center for Healthy Aging (HiHA), Hiroshima University, Higashi-Hiroshima 739-8530, Japan.,Laboratory of Molecular and Chemical Cell Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Yasuhiro Teratani
- Laboratory of Molecular and Chemical Cell Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Takashi Toda
- Hiroshima Research Center for Healthy Aging (HiHA), Hiroshima University, Higashi-Hiroshima 739-8530, Japan.,Laboratory of Molecular and Chemical Cell Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
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16
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High-Throughput Identification of Nuclear Envelope Protein Interactions in Schizosaccharomyces pombe Using an Arrayed Membrane Yeast-Two Hybrid Library. G3-GENES GENOMES GENETICS 2020; 10:4649-4663. [PMID: 33109728 PMCID: PMC7718735 DOI: 10.1534/g3.120.401880] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The nuclear envelope (NE) contains a specialized set of integral membrane proteins that maintain nuclear shape and integrity and influence chromatin organization and gene expression. Advances in proteomics techniques and studies in model organisms have identified hundreds of proteins that localize to the NE. However, the function of many of these proteins at the NE remains unclear, in part due to a lack of understanding of the interactions that these proteins participate in at the NE membrane. To assist in the characterization of NE transmembrane protein interactions we developed an arrayed library of integral and peripheral membrane proteins from the fission yeast Schizosaccharomyces pombe for high-throughput screening using the split-ubiquitin based membrane yeast two -hybrid system. We used this approach to characterize protein interactions for three conserved proteins that localize to the inner nuclear membrane: Cut11/Ndc1, Lem2 and Ima1/Samp1/Net5. Additionally, we determined how the interaction network for Cut11 is altered in canonical temperature-sensitive cut11-ts mutants. This library and screening approach is readily applicable to characterizing the interactomes of integral membrane proteins localizing to various subcellular compartments.
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17
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Abstract
During closed mitosis in fission yeast, growing microtubules push onto the nuclear envelope to deform it, which results in fission into two daughter nuclei. The resistance of the envelope to bending, quantified by the flexural stiffness, helps determine the microtubule-dependent nuclear shape transformations. Computational models of envelope mechanics have assumed values of the flexural stiffness of the envelope based on simple scaling arguments. The validity of these estimates is in doubt, however, owing to the complex structure of the nuclear envelope. Here, we performed computational analysis of the bending of the nuclear envelope under applied force using a model that accounts for envelope geometry. Our calculations show that the effective bending modulus of the nuclear envelope is an order of magnitude larger than a single membrane and approximately five times greater than the nuclear lamina. This large bending modulus is in part due to the 45 nm separation between the two membranes, which supports larger bending moments in the structure. Further, the effective bending modulus is highly sensitive to the geometry of the nuclear envelope, ranging from twofold to an order magnitude larger than the corresponding single membrane. These results suggest that spatial variations in geometry and mechanical environment of the envelope may cause a spatial distribution of flexural stiffness in the same nucleus. Overall, our calculations support the possibility that the nuclear envelope may balance significant mechanical stresses in yeast and in cells from higher organisms.
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Affiliation(s)
- Ashutosh Agrawal
- Department of Mechanical Engineering, University of Houston, Houston, TX 77204
| | - Tanmay P Lele
- Department of Biomedical Engineering and Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
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18
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Liu W, Zheng F, Wang Y, Fu C. Alp7-Mto1 and Alp14 synergize to promote interphase microtubule regrowth from the nuclear envelope. J Mol Cell Biol 2020; 11:944-955. [PMID: 31087092 PMCID: PMC6927237 DOI: 10.1093/jmcb/mjz038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/15/2019] [Accepted: 04/26/2019] [Indexed: 01/02/2023] Open
Abstract
Microtubules grow not only from the centrosome but also from various noncentrosomal microtubule-organizing centers (MTOCs), including the nuclear envelope (NE) and pre-existing microtubules. The evolutionarily conserved proteins Mto1/CDK5RAP2 and Alp14/TOG/XMAP215 have been shown to be involved in promoting microtubule nucleation. However, it has remained elusive as to how the microtubule nucleation promoting factors are specified to various noncentrosomal MTOCs, particularly the NE, and how these proteins coordinate to organize microtubule assembly. Here, we demonstrate that in the fission yeast Schizosaccharomyces pombe, efficient interphase microtubule growth from the NE requires Alp7/TACC, Alp14/TOG/XMAP215, and Mto1/CDK5RAP2. The absence of Alp7, Alp14, or Mto1 compromises microtubule regrowth on the NE in cells undergoing microtubule repolymerization. We further demonstrate that Alp7 and Mto1 interdependently localize to the NE in cells without microtubules and that Alp14 localizes to the NE in an Alp7 and Mto1-dependent manner. Tethering Mto1 to the NE in cells lacking Alp7 partially restores microtubule number and the efficiency of microtubule generation from the NE. Hence, our study delineates that Alp7, Alp14, and Mto1 work in concert to regulate interphase microtubule regrowth on the NE.
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Affiliation(s)
- Wenyue Liu
- Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences, University of Science and Technology of China, Hefei, China.,Chinese Academy of Sciences Center for Excellence in Molecular Cell Sciences, School of Life Sciences, University of Science and Technology of China, Hefei, China.,Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, China
| | - Fan Zheng
- Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences, University of Science and Technology of China, Hefei, China.,Chinese Academy of Sciences Center for Excellence in Molecular Cell Sciences, School of Life Sciences, University of Science and Technology of China, Hefei, China.,Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, China
| | - Yucai Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Chuanhai Fu
- Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences, University of Science and Technology of China, Hefei, China.,Chinese Academy of Sciences Center for Excellence in Molecular Cell Sciences, School of Life Sciences, University of Science and Technology of China, Hefei, China.,Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, China
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19
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Native Chromatin Proteomics Reveals a Role for Specific Nucleoporins in Heterochromatin Organization and Maintenance. Mol Cell 2019; 77:51-66.e8. [PMID: 31784357 DOI: 10.1016/j.molcel.2019.10.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/19/2019] [Accepted: 10/11/2019] [Indexed: 12/31/2022]
Abstract
Spatially and functionally distinct domains of heterochromatin and euchromatin play important roles in the maintenance of chromosome stability and regulation of gene expression, but a comprehensive knowledge of their composition is lacking. Here, we develop a strategy for the isolation of native Schizosaccharomyces pombe heterochromatin and euchromatin fragments and analyze their composition by using quantitative mass spectrometry. The shared and euchromatin-specific proteomes contain proteins involved in DNA and chromatin metabolism and in transcription, respectively. The heterochromatin-specific proteome includes all proteins with known roles in heterochromatin formation and, in addition, is enriched for subsets of nucleoporins and inner nuclear membrane (INM) proteins, which associate with different chromatin domains. While the INM proteins are required for the integrity of the nucleolus, containing ribosomal DNA repeats, the nucleoporins are required for aggregation of heterochromatic foci and epigenetic inheritance. The results provide a comprehensive picture of heterochromatin-associated proteins and suggest a role for specific nucleoporins in heterochromatin function.
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20
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Cantwell H, Nurse P. A homeostatic mechanism rapidly corrects aberrant nucleocytoplasmic ratios maintaining nuclear size in fission yeast. J Cell Sci 2019; 132:jcs.235911. [PMID: 31649142 PMCID: PMC6899009 DOI: 10.1242/jcs.235911] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/18/2019] [Indexed: 12/21/2022] Open
Abstract
Nuclear size scales with cell size across a wide range of cell types. The mechanism by which this scaling is maintained in growing cells remains unclear. Here, we investigate the mechanism of nuclear size homeostasis in the simple eukaryote fission yeast, by monitoring the recovery of aberrant nuclear volume to cell volume (N/C) ratios following perturbation. We demonstrate that both high and low N/C ratios correct rapidly, maintaining nuclear size homeostasis. We assess the kinetics of nuclear and cellular growth and of N/C ratio correction, and demonstrate that nuclear and cellular growth rates are not directly coupled. We propose that the mechanism underlying nuclear size homeostasis involves multiple limiting factors implicated in processes including nucleocytoplasmic transport, lipid biogenesis and RNA processing. We speculate that these link cellular size increases to changes in nuclear contents, which in turn lead to changes in nuclear membrane surface area. Our study reveals that there is rapid nuclear size homeostasis in cells, informing understanding of nuclear size control and size homeostasis of other membrane-bound organelles. Summary: Nuclear size homeostasis is achieved by a rapid correction mechanism modulating nuclear growth rate in growing fission yeast cells.
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Affiliation(s)
- Helena Cantwell
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Paul Nurse
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK.,Laboratory of Yeast Genetics and Cell Biology, Rockefeller University, New York, NY 10065, USA
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21
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Pinder C, Matsuo Y, Maurer SP, Toda T. Kinesin-8 and Dis1/TOG collaborate to limit spindle elongation from prophase to anaphase A for proper chromosome segregation in fission yeast. J Cell Sci 2019; 132:jcs232306. [PMID: 31427431 PMCID: PMC6765184 DOI: 10.1242/jcs.232306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/09/2019] [Indexed: 12/15/2022] Open
Abstract
High-fidelity chromosome segregation relies on proper microtubule regulation. Kinesin-8 has been shown to destabilise microtubules to reduce metaphase spindle length and chromosome movements in multiple species. XMAP215/chTOG polymerases catalyse microtubule growth for spindle assembly, elongation and kinetochore-microtubule attachment. Understanding of their biochemical activity has advanced, but little work directly addresses the functionality and interplay of these conserved factors. We utilised the synthetic lethality of fission yeast kinesin-8 (Klp5-Klp6) and XMAP215/chTOG (Dis1) to study their individual and overlapping roles. We found that the non-motor kinesin-8 tailbox is essential for mitotic function; mutation compromises plus-end-directed processivity. Klp5-Klp6 induces catastrophes to control microtubule length and, surprisingly, Dis1 collaborates with kinesin-8 to slow spindle elongation. Together, they enforce a maximum spindle length for a viable metaphase-anaphase transition and limit elongation during anaphase A to prevent lagging chromatids. Our work provides mechanistic insight into how kinesin-8 negatively regulates microtubules and how this functionally overlaps with Dis1 and highlights the importance of spindle length control in mitosis.
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Affiliation(s)
- Corinne Pinder
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Division of Biological and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Yuzy Matsuo
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Sebastian P Maurer
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
| | - Takashi Toda
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Division of Biological and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Hiroshima Research Center for Healthy Aging (HiHA), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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22
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Salas-Pino S, Daga RR. Spatiotemporal control of spindle disassembly in fission yeast. Cell Mol Life Sci 2019; 76:3543-3551. [PMID: 31129857 PMCID: PMC11105212 DOI: 10.1007/s00018-019-03139-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 12/20/2022]
Abstract
Maintenance of genomic stability during cell division is one of the most important cellular tasks, and it critically depends on the faithful replication of the genetic material and its equal partitioning into daughter cells, gametes, or spores in the case of yeasts. Defective mitotic spindle assembly and disassembly both result in changes in cellular ploidy that ultimately impinge proliferation fitness and might increase tumor malignancy. Although a great progress has been made in understanding how spindles are assembled to orchestrate chromosome segregation, much less is known about how they are disassembled once completed their function. Here, we review two recently uncovered mechanisms of spindle disassembly that operate at different stages of the fission yeast life cycle.
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Affiliation(s)
- Silvia Salas-Pino
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucia, Carretera de Utrera, km1, 41013, Seville, Spain.
| | - Rafael R Daga
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucia, Carretera de Utrera, km1, 41013, Seville, Spain.
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23
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Spindle assembly without spindle pole body insertion into the nuclear envelope in fission yeast meiosis. Chromosoma 2019; 128:267-277. [PMID: 31152193 DOI: 10.1007/s00412-019-00710-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 05/09/2019] [Accepted: 05/16/2019] [Indexed: 01/23/2023]
Abstract
Centrosomes represent the major microtubule organizing center (MTOC) in eukaryotic cells and are responsible for nucleation of the spindle, the vehicle of chromosome segregation. In human female meiosis, however, spindle assembly occurs in the absence of centrosomes or other MTOCs and microtubules are nucleated around chromosomes. In yeast, spindle formation in mitosis and meiosis depends on the activity of spindle pole bodies (SPBs), the functional equivalents of centrosomes; thus, SPBs and centrosomes use similar machineries to assemble spindles. Here, we develop a system to explore the molecular mechanisms supporting acentrosomal spindle formation using fission yeast meiosis as a model scenario. We achieve this situation by removing access of the SPBs to the nucleus after their duplication. Under these conditions, we observe self-assembly-based spindle formation in the nuclear environment, conferring an ability to segregate chromosomes independently of the SPBs. Our results open the possibility to utilize the experimental advantages of fission yeast for insights into the molecular basis of acentrosomal spindle formation in meiosis.
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24
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Spindle pole body movement is affected by glucose and ammonium chloride in fission yeast. Biochem Biophys Res Commun 2019; 511:820-825. [PMID: 30846209 DOI: 10.1016/j.bbrc.2019.02.128] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 02/23/2019] [Indexed: 02/06/2023]
Abstract
The complexity of chromatin dynamics is orchestrated by several active processes. In fission yeast, the centromeres are clustered around the spindle pole body (SPB) and oscillate in a microtubule- and adenosine triphosphate (ATP)-dependent manner. However, whether and how SPB oscillation are affected by different environmental conditions remain poorly understood. In this study, we quantitated movements of the SPB component, which colocalizes with the centromere in fission yeast. We found that SPB movement was significantly reduced at low glucose concentrations. Movement of the SPB was also affected by the presence of ammonium chloride. Power spectral analysis revealed that periodic movement of the SPB is disrupted by low glucose concentrations. Measurement of ATP levels in living cells by quantitative single-cell imaging suggests that ATP levels are not the only determinant of SPB movement. Our results provide novel insight into how SPB movement is regulated by cellular energy status and additional factors such as the medium nutritional composition.
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25
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Suppressor Analysis Uncovers That MAPs and Microtubule Dynamics Balance with the Cut7/Kinesin-5 Motor for Mitotic Spindle Assembly in Schizosaccharomyces pombe. G3-GENES GENOMES GENETICS 2019; 9:269-280. [PMID: 30463883 PMCID: PMC6325904 DOI: 10.1534/g3.118.200896] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Kinesin-5 motor Cut7 in Schizosaccharomyces pombe plays essential roles in spindle pole separation, leading to the assembly of bipolar spindle. In many organisms, simultaneous inactivation of Kinesin-14s neutralizes Kinesin-5 deficiency. To uncover the molecular network that counteracts Kinesin-5, we have conducted a genetic screening for suppressors that rescue the cut7-22 temperature sensitive mutation, and identified 10 loci. Next generation sequencing analysis reveals that causative mutations are mapped in genes encoding α-, β-tubulins and the microtubule plus-end tracking protein Mal3/EB1, in addition to the components of the Pkl1/Kinesin-14 complex. Moreover, the deletion of various genes required for microtubule nucleation/polymerization also suppresses the cut7 mutant. Intriguingly, Klp2/Kinesin-14 levels on the spindles are significantly increased in cut7 mutants, whereas these increases are negated by suppressors, which may explain the suppression by these mutations/deletions. Consistent with this notion, mild overproduction of Klp2 in these double mutant cells confers temperature sensitivity. Surprisingly, treatment with a microtubule-destabilizing drug not only suppresses cut7 temperature sensitivity but also rescues the lethality resulting from the deletion of cut7, though a single klp2 deletion per se cannot compensate for the loss of Cut7. We propose that microtubule assembly and/or dynamics antagonize Cut7 functions, and that the orchestration between these two factors is crucial for bipolar spindle assembly.
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26
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Zach R, Převorovský M. The phenomenon of lipid metabolism "cut" mutants. Yeast 2018; 35:631-637. [PMID: 30278108 DOI: 10.1002/yea.3358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/06/2018] [Accepted: 09/24/2018] [Indexed: 02/05/2023] Open
Abstract
Every cell cycle iteration culminates with the resolution of a mitotic nucleus into a pair of daughter nuclei, which are distributed between the two daughter cells. In the fission yeast Schizosaccharomyces pombe, the faithful division of a mitotic nucleus depends on unperturbed lipogenesis. Upon genetically or chemically induced perturbation of lipid anabolism, S. pombe cells fail to separate the two daughter nuclei and subsequently initiate lethal cytokinesis resulting in the so-called "cut" terminal phenotype. Evidence supporting a critical role of lipid biogenesis in successful mitosis in S. pombe has been accumulating for almost two decades, but the exact mechanism explaining the reported observations had been elusive. Recently, several studies established a functional link between biosynthesis of structural phospholipids, nuclear membrane growth, and the fidelity of "closed" mitosis in S. pombe. These novel insights suggest a mechanistic explanation for the mitotic defects characteristic for some S. pombe mutants deficient in lipid anabolism and extend our knowledge of metabolic modulation within the context of the cell cycle. In this review, we cover the essential role of lipogenesis in "closed" mitosis, focusing mainly on S. pombe as a model system.
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Affiliation(s)
- Róbert Zach
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic.,Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
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27
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Sajiki K, Tahara Y, Uehara L, Sasaki T, Pluskal T, Yanagida M. Genetic regulation of mitotic competence in G 0 quiescent cells. SCIENCE ADVANCES 2018; 4:eaat5685. [PMID: 30116786 PMCID: PMC6093628 DOI: 10.1126/sciadv.aat5685] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/04/2018] [Indexed: 05/03/2023]
Abstract
Quiescent (G0 phase) cells must maintain mitotic competence (MC) to restart the cell cycle. This is essential for reproduction in unicellular organisms and also for development and cell replacement in higher organisms. Recently, suppression of MC has gained attention as a possible therapeutic strategy for cancer. Using a Schizosaccharomyces pombe deletion-mutant library, we identified 85 genes required to maintain MC during the G0 phase induced by nitrogen deprivation. G0 cells must recycle proteins and RNA, governed by anabolism, catabolism, transport, and availability of small molecules such as antioxidants. Protein phosphatases are also essential to maintain MC. In particular, Nem1-Spo7 protects the nucleus from autophagy by regulating Ned1, a lipin. These genes, designated GZE (G-Zero Essential) genes, reveal the landscape of genetic regulation of MC.
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Affiliation(s)
- Kenichi Sajiki
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna, Okinawa, Japan
- Corresponding author. (K.S.); (M.Y.)
| | - Yuria Tahara
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna, Okinawa, Japan
| | - Lisa Uehara
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna, Okinawa, Japan
| | - Toshio Sasaki
- Research Support Imaging Section, OIST, Onna, Okinawa, Japan
| | - Tomáš Pluskal
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna, Okinawa, Japan
| | - Mitsuhiro Yanagida
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna, Okinawa, Japan
- Corresponding author. (K.S.); (M.Y.)
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28
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Ito D, Bettencourt-Dias M. Centrosome Remodelling in Evolution. Cells 2018; 7:E71. [PMID: 29986477 PMCID: PMC6070874 DOI: 10.3390/cells7070071] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 06/27/2018] [Accepted: 07/04/2018] [Indexed: 11/16/2022] Open
Abstract
The centrosome is the major microtubule organizing centre (MTOC) in animal cells. The canonical centrosome is composed of two centrioles surrounded by a pericentriolar matrix (PCM). In contrast, yeasts and amoebozoa have lost centrioles and possess acentriolar centrosomes—called the spindle pole body (SPB) and the nucleus-associated body (NAB), respectively. Despite the difference in their structures, centriolar centrosomes and SPBs not only share components but also common biogenesis regulators. In this review, we focus on the SPB and speculate how its structures evolved from the ancestral centrosome. Phylogenetic distribution of molecular components suggests that yeasts gained specific SPB components upon loss of centrioles but maintained PCM components associated with the structure. It is possible that the PCM structure remained even after centrosome remodelling due to its indispensable function to nucleate microtubules. We propose that the yeast SPB has been formed by a step-wise process; (1) an SPB-like precursor structure appeared on the ancestral centriolar centrosome; (2) it interacted with the PCM and the nuclear envelope; and (3) it replaced the roles of centrioles. Acentriolar centrosomes should continue to be a great model to understand how centrosomes evolved and how centrosome biogenesis is regulated.
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Affiliation(s)
- Daisuke Ito
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
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29
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Snider CE, Willet AH, Brown HT, Gould KL. Analysis of the contribution of phosphoinositides to medial septation in fission yeast highlights the importance of PI(4,5)P 2 for medial contractile ring anchoring. Mol Biol Cell 2018; 29:2148-2155. [PMID: 29975157 PMCID: PMC6249800 DOI: 10.1091/mbc.e18-03-0179] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In Schizosaccharomyces pombe, loss of the plasma membrane PI4-kinase scaffold Efr3 leads to sliding of the cytokinetic ring (CR) away from the cell center during anaphase, implicating phosphoinositides (PIPs) in CR anchoring. However, whether other PIP regulators contribute to CR anchoring has not been investigated. Here we report that mutants of other PIP kinases and their regulators divide with off-center septa, similar to efr3∆. Using new biosensors for S. pombe PIPs, we confirm that these mutants have disrupted PIP composition. We extend a previous finding that a mutant known to decrease PI(3,5)P2 levels indirectly affects CR positioning by increasing vacuole size which disrupts nuclear position at the onset of mitosis. Indeed, we found that other mutants with increased vacuole size also disrupt medial division via this mechanism. Although elevated plasma membrane PI(4,5)P2 levels do not affect medial cytokinesis, mutants with decreased levels display CR sliding events indicating a specific role for PI(4,5)P2 in CR anchoring.
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Affiliation(s)
- Chloe E Snider
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - HannahSofia T Brown
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
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Niimi T, Nakamura T. The fission yeast SPB component Dms1 is required to initiate forespore membrane formation and maintain meiotic SPB components. PLoS One 2018; 13:e0197879. [PMID: 29813128 PMCID: PMC5973557 DOI: 10.1371/journal.pone.0197879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 05/09/2018] [Indexed: 11/19/2022] Open
Abstract
The spindle pole body (SPB) plays a central role in spore plasma membrane formation in addition to its recognized role in microtubule organization. During meiosis, a biomembrane called the forespore membrane (FSM) is newly formed at the SPB. Although several SPB proteins essential for the initiation of FSM formation (meiotic SPB components) have been identified, the molecular mechanism is still unknown. Here, we report the isolation and functional characterization of Dms1 as a component of the SPB. We show that FSM formation does not initiate in dms1Δ cells. Dms1 protein is constitutively expressed throughout the life cycle and localizes to the SPB and the nuclear envelope. The predicted Dms1 protein has a transmembrane domain, which is required for correct localization at the SPB. Dms1 is essential for the proper localization of three meiotic SPB components, Spo15, Spo2, and Spo13, but these components do not affect localization of Dms1. Collectively, these results suggest that Dms1 anchors these meiotic SPB components to the SPB, thereby facilitating the initiation of FSM formation.
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Affiliation(s)
- Touko Niimi
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan
| | - Taro Nakamura
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan
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31
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G. Cortés JC, Ramos M, Konomi M, Barragán I, Moreno MB, Alcaide-Gavilán M, Moreno S, Osumi M, Pérez P, Ribas JC. Specific detection of fission yeast primary septum reveals septum and cleavage furrow ingression during early anaphase independent of mitosis completion. PLoS Genet 2018; 14:e1007388. [PMID: 29813053 PMCID: PMC5993333 DOI: 10.1371/journal.pgen.1007388] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 06/08/2018] [Accepted: 05/01/2018] [Indexed: 11/27/2022] Open
Abstract
It is widely accepted in eukaryotes that the cleavage furrow only initiates after mitosis completion. In fission yeast, cytokinesis requires the synthesis of a septum tightly coupled to cleavage furrow ingression. The current cytokinesis model establishes that simultaneous septation and furrow ingression only initiate after spindle breakage and mitosis exit. Thus, this model considers that although Cdk1 is inactivated at early-anaphase, septation onset requires the long elapsed time until mitosis completion and full activation of the Hippo-like SIN pathway. Here, we studied the precise timing of septation onset regarding mitosis by exploiting both the septum-specific detection with the fluorochrome calcofluor and the high-resolution electron microscopy during anaphase and telophase. Contrarily to the existing model, we found that both septum and cleavage furrow start to ingress at early anaphase B, long before spindle breakage, with a slow ingression rate during anaphase B, and greatly increasing after telophase onset. This shows that mitosis and cleavage furrow ingression are not concatenated but simultaneous events in fission yeast. We found that the timing of septation during early anaphase correlates with the cell size and is regulated by the corresponding levels of SIN Etd1 and Rho1. Cdk1 inactivation was directly required for timely septation in early anaphase. Strikingly the reduced SIN activity present after Cdk1 loss was enough to trigger septation by immediately inducing the medial recruitment of the SIN kinase complex Sid2-Mob1. On the other hand, septation onset did not depend on the SIN asymmetry establishment, which is considered a hallmark for SIN activation. These results recalibrate the timing of key cytokinetic events in fission yeast; and unveil a size-dependent control mechanism that synchronizes simultaneous nuclei separation with septum and cleavage furrow ingression to safeguard the proper chromosome segregation during cell division. Fission yeast cytokinesis requires the invagination of the equatorial plasma membrane (cleavage furrow ingression) coupled to the synthesis of a special wall structure named septum (septation). Despite Cdk1 kinase is inactivated in early anaphase, it is believed that cleavage furrow ingression and septation onset require anaphase progression and mitosis completion, only initiating after the complete activation of the Hippo-like septation initiation network (SIN) after telophase onset. Here, we studied the precise timing of septation start with respect to mitosis through specific septum-staining and electron microscopy. We found that septum and cleavage furrow ingression initiate in early anaphase, showing first a slow ingression rate during anaphase B, and increasing to a fast ingression rate after telophase onset. Thus, mitosis and cleavage furrow ingression are not concatenated but simultaneous events in fission yeast. The timing of septation correlated with cell size and depended on the level of cytoplasmic activators like SIN Etd1 and Rho1. We further analyzed the mitotic mechanisms that control the septation onset during early anaphase. Cdk1 directly regulated the timing of septation onset during early anaphase, and the low SIN activity present after Cdk1 inactivation was enough to trigger septation. Globally, these results recalibrate the timing of the main cytokinetic events of fission yeast and reveal a size-dependent control mechanism that synchronizes simultaneous nuclei separation with septum and cleavage furrow ingression.
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Affiliation(s)
- Juan Carlos G. Cortés
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
- * E-mail:
| | - Mariona Ramos
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - Mami Konomi
- Laboratory of Electron Microscopy/Bio-imaging Centre, and Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Bunkyo-ku, Tokyo, Japan
| | - Iris Barragán
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - M. Belén Moreno
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - María Alcaide-Gavilán
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Sergio Moreno
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - Masako Osumi
- Laboratory of Electron Microscopy/Bio-imaging Centre, and Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Bunkyo-ku, Tokyo, Japan
- NPO: Integrated Imaging Research Support, Hirakawa-cho, Chiyoda-ku, Tokyo, Japan
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - Juan Carlos Ribas
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
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Duplication and Nuclear Envelope Insertion of the Yeast Microtubule Organizing Centre, the Spindle Pole Body. Cells 2018; 7:cells7050042. [PMID: 29748517 PMCID: PMC5981266 DOI: 10.3390/cells7050042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/04/2018] [Accepted: 05/08/2018] [Indexed: 11/16/2022] Open
Abstract
The main microtubule organizing centre in the unicellular model organisms Saccharomyces cerevisiae and Schizosaccharomyces pompe is the spindle pole body (SPB). The SPB is a multilayer structure, which duplicates exactly once per cell cycle. Unlike higher eukaryotic cells, both yeast model organisms undergo mitosis without breakdown of the nuclear envelope (NE), a so-called closed mitosis. Therefore, in order to simultaneously nucleate nuclear and cytoplasmic MTs, it is vital to embed the SPB into the NE at least during mitosis, similarly to the nuclear pore complex (NPC). This review aims to embrace the current knowledge of the SPB duplication cycle with special emphasis on the critical step of the insertion of the new SPB into the NE.
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Ebrahimi H, Masuda H, Jain D, Cooper JP. Distinct 'safe zones' at the nuclear envelope ensure robust replication of heterochromatic chromosome regions. eLife 2018; 7:32911. [PMID: 29722648 PMCID: PMC5933923 DOI: 10.7554/elife.32911] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 03/30/2018] [Indexed: 12/24/2022] Open
Abstract
Chromosome replication and transcription occur within a complex nuclear milieu whose functional subdomains are beginning to be mapped out. Here we delineate distinct domains of the fission yeast nuclear envelope (NE), focusing on regions enriched for the inner NE protein, Bqt4, or the lamin interacting domain protein, Lem2. Bqt4 is relatively mobile around the NE and acts in two capacities. First, Bqt4 tethers chromosome termini and the mat locus to the NE specifically while these regions are replicating. This positioning is required for accurate heterochromatin replication. Second, Bqt4 mobilizes a subset of Lem2 molecules around the NE to promote pericentric heterochromatin maintenance. Opposing Bqt4-dependent Lem2 mobility are factors that stabilize Lem2 beneath the centrosome, where Lem2 plays a crucial role in kinetochore maintenance. Our data prompt a model in which Bqt4-rich nuclear subdomains are 'safe zones' in which collisions between transcription and replication are averted and heterochromatin is reassembled faithfully.
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Affiliation(s)
- Hani Ebrahimi
- Telomere Biology Section, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
| | - Hirohisa Masuda
- Telomere Biology Section, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
| | - Devanshi Jain
- Telomere Biology Section, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
| | - Julia Promisel Cooper
- Telomere Biology Section, Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
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Yukawa M, Yamada Y, Yamauchi T, Toda T. Two spatially distinct kinesin-14 proteins, Pkl1 and Klp2, generate collaborative inward forces against kinesin-5 Cut7 in S. pombe. J Cell Sci 2018; 131:jcs.210740. [PMID: 29167352 DOI: 10.1242/jcs.210740] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 11/16/2017] [Indexed: 01/15/2023] Open
Abstract
Kinesin motors play central roles in bipolar spindle assembly. In many eukaryotes, spindle pole separation is driven by kinesin-5, which generates outward force. This outward force is balanced by antagonistic inward force elicited by kinesin-14 and/or dynein. In fission yeast, two kinesin-14 proteins, Pkl1 and Klp2, play an opposing role against the kinesin-5 motor protein Cut7. However, how the two kinesin-14 proteins coordinate individual activities remains elusive. Here, we show that although deletion of either pkl1 or klp2 rescues temperature-sensitive cut7 mutants, deletion of only pkl1 can bypass the lethality caused by cut7 deletion. Pkl1 is tethered to the spindle pole body, whereas Klp2 is localized along the spindle microtubule. Forced targeting of Klp2 to the spindle pole body, however, compensates for Pkl1 functions, indicating that cellular localizations, rather than individual motor specificities, differentiate between the two kinesin-14 proteins. Interestingly, human kinesin-14 (KIFC1 or HSET) can replace either Pkl1 or Klp2. Moreover, overproduction of HSET induces monopolar spindles, reminiscent of the phenotype of Cut7 inactivation. Taken together, this study has uncovered the biological mechanism whereby two different Kinesin-14 motor proteins exert their antagonistic roles against kinesin-5 in a spatially distinct manner.
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Affiliation(s)
- Masashi Yukawa
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Yusuke Yamada
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Tomoaki Yamauchi
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takashi Toda
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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35
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Nakazawa N, Teruya T, Sajiki K, Kumada K, Villar-Briones A, Arakawa O, Takada J, Saitoh S, Yanagida M. Fission yeast ceramide ts mutants cwh43 exhibit defects in G0 quiescence, nutrient metabolism, and lipid homeostasis. J Cell Sci 2018; 131:jcs.217331. [DOI: 10.1242/jcs.217331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/20/2018] [Indexed: 12/17/2022] Open
Abstract
Cellular nutrient states control whether cells proliferate, or whether they enter or exit quiescence. Here, we report characterizations of fission yeast temperature-sensitive (ts) mutants of the evolutionarily conserved transmembrane protein, Cwh43, and explore its relevance to utilization of glucose, nitrogen-source, and lipids. GFP-tagged Cwh43 localizes at ER associated with the nuclear envelope and the plasma membrane, as in budding yeast. We found that cwh43 mutants failed to divide in low glucose and lost viability during quiescence under nitrogen starvation. In cwh43 mutant, comprehensive metabolome analysis demonstrated dramatic changes in marker metabolites that altered under low glucose and/or nitrogen starvation, although cwh43 apparently consumed glucose in the culture media. Furthermore, we found that cwh43 mutant had elevated levels of triacylglycerols (TGs) and coenzyme A, and that it accumulated lipid droplets. Notably, TG biosynthesis was required to maintain cell division in cwh43 mutant. Thus, Cwh43 affects utilization of glucose and nitrogen-sources, as well as storage lipid metabolism. These results may fit to a notion developed in budding yeast that Cwh43 conjugates ceramide to GPI (glycosylphosphatidylinositol)-anchored proteins and maintains integrity of membrane organization.
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Affiliation(s)
- Norihiko Nakazawa
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Takayuki Teruya
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Kenichi Sajiki
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Kazuki Kumada
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Alejandro Villar-Briones
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Orie Arakawa
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Junko Takada
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Shigeaki Saitoh
- Institute of Life Science, Kurume University, Hyakunen-Kohen 1-1, Kurume, Fukuoka 839-0864, Japan
| | - Mitsuhiro Yanagida
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
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Aoki K, Niki H. Release of condensin from mitotic chromosomes requires the Ran-GTP gradient in the reorganized nucleus. Biol Open 2017; 6:1614-1628. [PMID: 28954740 PMCID: PMC5703609 DOI: 10.1242/bio.027193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
After mitosis, nuclear reorganization occurs together with decondensation of mitotic chromosomes and reformation of the nuclear envelope, thereby restoring the Ran-GTP gradient between the nucleus and cytoplasm. The Ran-GTP gradient is dependent on Pim1/RCC1. Interestingly, a defect in Pim1/RCC1 in Schizosaccharomyces pombe causes postmitotic condensation of chromatin, namely hypercondensation, suggesting a relationship between the Ran-GTP gradient and chromosome decondensation. However, how Ran-GTP interacts with chromosome decondensation is unresolved. To examine this interaction, we used Schizosaccharomyces japonicus, which is known to undergo partial breakdown of the nuclear membrane during mitosis. We found that Pim1/RCC1 was localized on nuclear pores, but this localization failed in a temperature-sensitive mutant of Pim1/RCC1. The mutant cells exhibited hypercondensed chromatin after mitosis due to prolonged association of condensin on the chromosomes. Conceivably, a condensin-dephosphorylation defect might cause hypercondensed chromatin, since chromosomal localization of condensin is dependent on phosphorylation by cyclin-dependent kinase (CDK). Indeed, CDK-phospho-mimic mutation of condensin alone caused untimely condensin localization, resulting in hypercondensed chromatin. Together, these results suggest that dephosphorylation of CDK sites of condensin might require the Ran-GTP gradient produced by nuclear pore-localized Pim1/RCC1. Summary: A mutant of Pim1/RCC1 caused hypercondensed chromatin after mitosis due to prolonged association of condensin on chromosomes, suggesting that dephosphorylation of CDK sites of condensin might require Ran-GTP after mitosis.
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Affiliation(s)
- Keita Aoki
- Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan .,Department of Genetics, SOKENDAI, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Hironori Niki
- Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.,Department of Genetics, SOKENDAI, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
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Cavanaugh AM, Jaspersen SL. Big Lessons from Little Yeast: Budding and Fission Yeast Centrosome Structure, Duplication, and Function. Annu Rev Genet 2017; 51:361-383. [PMID: 28934593 DOI: 10.1146/annurev-genet-120116-024733] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Centrosomes are a functionally conserved feature of eukaryotic cells that play an important role in cell division. The conserved γ-tubulin complex organizes spindle and astral microtubules, which, in turn, separate replicated chromosomes accurately into daughter cells. Like DNA, centrosomes are duplicated once each cell cycle. Although in some cell types it is possible for cell division to occur in the absence of centrosomes, these divisions typically result in defects in chromosome number and stability. In single-celled organisms such as fungi, centrosomes [known as spindle pole bodies (SPBs)] are essential for cell division. SPBs also must be inserted into the membrane because fungi undergo a closed mitosis in which the nuclear envelope (NE) remains intact. This poorly understood process involves events similar or identical to those needed for de novo nuclear pore complex assembly. Here, we review how analysis of fungal SPBs has advanced our understanding of centrosomes and NE events.
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Affiliation(s)
- Ann M Cavanaugh
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA;
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA; .,Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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Fernández-Álvarez A, Bez C, O'Toole ET, Morphew M, Cooper JP. Mitotic Nuclear Envelope Breakdown and Spindle Nucleation Are Controlled by Interphase Contacts between Centromeres and the Nuclear Envelope. Dev Cell 2016; 39:544-559. [PMID: 27889481 DOI: 10.1016/j.devcel.2016.10.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 09/02/2016] [Accepted: 10/26/2016] [Indexed: 10/20/2022]
Abstract
Faithful genome propagation requires coordination between nuclear envelope (NE) breakdown, spindle formation, and chromosomal events. The conserved linker of nucleoskeleton and cytoskeleton (LINC) complex connects fission yeast centromeres and the centrosome, across the NE, during interphase. During meiosis, LINC connects the centrosome with telomeres rather than centromeres. We previously showed that loss of telomere-LINC contacts compromises meiotic spindle formation. Here, we define the precise events regulated by telomere-LINC contacts and address the analogous possibility that centromeres regulate mitotic spindle formation. We develop conditionally inactivated LINC complexes in which the conserved SUN-domain protein Sad1 remains stable but severs interphase centromere-LINC contacts. Strikingly, the loss of such contacts abolishes spindle formation. We pinpoint the defect to a failure in the partial NE breakdown required for centrosome insertion into the NE, a step analogous to mammalian NE breakdown. Thus, interphase chromosome-LINC contacts constitute a cell-cycle control device linking nucleoplasmic and cytoplasmic events.
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Affiliation(s)
- Alfonso Fernández-Álvarez
- Telomere Biology Section, LBMB, National Cancer Institute, NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA; Telomere Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
| | - Cécile Bez
- Telomere Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Eileen T O'Toole
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Mary Morphew
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Julia Promisel Cooper
- Telomere Biology Section, LBMB, National Cancer Institute, NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA; Telomere Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
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39
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A Taz1- and Microtubule-Dependent Regulatory Relationship between Telomere and Centromere Positions in Bouquet Formation Secures Proper Meiotic Divisions. PLoS Genet 2016; 12:e1006304. [PMID: 27611693 PMCID: PMC5017736 DOI: 10.1371/journal.pgen.1006304] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/17/2016] [Indexed: 01/01/2023] Open
Abstract
During meiotic prophase, telomeres cluster, forming the bouquet chromosome arrangement, and facilitate homologous chromosome pairing. In fission yeast, bouquet formation requires switching of telomere and centromere positions. Centromeres are located at the spindle pole body (SPB) during mitotic interphase, and upon entering meiosis, telomeres cluster at the SPB, followed by centromere detachment from the SPB. Telomere clustering depends on the formation of the microtubule-organizing center at telomeres by the linker of nucleoskeleton and cytoskeleton complex (LINC), while centromere detachment depends on disassembly of kinetochores, which induces meiotic centromere formation. However, how the switching of telomere and centromere positions occurs during bouquet formation is not fully understood. Here, we show that, when impaired telomere interaction with the LINC or microtubule disruption inhibited telomere clustering, kinetochore disassembly-dependent centromere detachment and accompanying meiotic centromere formation were also inhibited. Efficient centromere detachment required telomere clustering-dependent SPB recruitment of a conserved telomere component, Taz1, and microtubules. Furthermore, when artificial SPB recruitment of Taz1 induced centromere detachment in telomere clustering-defective cells, spindle formation was impaired. Thus, detachment of centromeres from the SPB without telomere clustering causes spindle impairment. These findings establish novel regulatory mechanisms, which prevent concurrent detachment of telomeres and centromeres from the SPB during bouquet formation and secure proper meiotic divisions. Meiosis is a type of cell division, that generates haploid gametes and is essential for sexual reproduction. During meiosis, telomeres cluster on a small region of the nuclear periphery, forming a conserved chromosome arrangement referred to as the “bouquet”. Because the bouquet arrangement facilitates homologous chromosome pairing, which is essential for proper meiotic chromosome segregation, it is of great importance to understand how the bouquet arrangement is formed. In fission yeast, the bouquet arrangement requires switching of telomere and centromere positions. During mitosis, centromeres are located at the fungal centrosome called the spindle pole body (SPB). Upon entering meiosis, telomeres cluster at the SPB, and centromeres become detached from the SPB, forming the bouquet arrangement. In this study, we show that centromere detachment is linked with telomere clustering. When telomere clustering was inhibited, centromere detachment was also inhibited. This regulatory relationship depended on a conserved telomere component, Taz1, and microtubules. Furthermore, we show that the regulatory relationship is crucial for proper meiotic divisions when telomere clustering is defective. Our findings reveal a hitherto unknown regulatory relationship between meiotic telomere and centromere positions in bouquet formation, which secures proper meiotic divisions.
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40
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Makarova M, Oliferenko S. Mixing and matching nuclear envelope remodeling and spindle assembly strategies in the evolution of mitosis. Curr Opin Cell Biol 2016; 41:43-50. [PMID: 27062548 PMCID: PMC7100904 DOI: 10.1016/j.ceb.2016.03.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/20/2016] [Accepted: 03/23/2016] [Indexed: 12/11/2022]
Abstract
In eukaryotes, cellular genome is enclosed inside a membrane-bound organelle called the nucleus. The nucleus compartmentalizes genome replication, repair and expression, keeping these activities separated from protein synthesis and other metabolic processes. Each proliferative division, the duplicated chromosomes must be equipartitioned between the daughter cells and this requires precise coordination between assembly of the microtubule-based mitotic spindle and nuclear remodeling. Here we review a surprising variety of strategies used by modern eukaryotes to manage these processes and discuss possible mechanisms that might have led to the emergence of this diversity in evolution.
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Affiliation(s)
- Maria Makarova
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Snezhana Oliferenko
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK.
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41
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Hui TH, Zheng F, Lin Y, Fu C. The linear and rotational motions of the fission yeast nucleus are governed by the stochastic dynamics of spatially distributed microtubules. J Biomech 2016; 49:1034-1041. [DOI: 10.1016/j.jbiomech.2016.02.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/22/2016] [Accepted: 02/07/2016] [Indexed: 12/01/2022]
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42
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Schwartz TU. The Structure Inventory of the Nuclear Pore Complex. J Mol Biol 2016; 428:1986-2000. [PMID: 27016207 DOI: 10.1016/j.jmb.2016.03.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/09/2016] [Accepted: 03/15/2016] [Indexed: 11/18/2022]
Abstract
The nuclear pore complex (NPC) is the principal gateway for molecular exchange between nucleus and cytoplasm across the nuclear envelope. Due to its sheer size of estimated 50-112MDa and its complex buildup from about 500-1000 individual proteins, it is a difficult object to study for structural biologists. Here, I review the extensive ensemble of high-resolution structures of the building blocks of the NPC. Concurrent with the increase in size and complexity, these latest, large structures and assemblies can now be used as the basis for hybrid approaches, primarily in combination with cryo-electron microscopic analysis, generating the first structure-based assembly models of the NPC. Going forward, the structures will be critically important for a detailed analysis of the NPC, including function, evolution, and assembly.
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Affiliation(s)
- Thomas U Schwartz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
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43
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Takemoto A, Kawashima SA, Li JJ, Jeffery L, Yamatsugu K, Elemento O, Nurse P. Nuclear envelope expansion is crucial for proper chromosomal segregation during a closed mitosis. J Cell Sci 2016; 129:1250-9. [PMID: 26869222 PMCID: PMC4813296 DOI: 10.1242/jcs.181560] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 02/01/2016] [Indexed: 01/29/2023] Open
Abstract
Here, we screened a 10,371 library of diverse molecules using a drug-sensitive fission yeast strain to identify compounds which cause defects in chromosome segregation during mitosis. We identified a phosphorium-ylide-based compound Cutin-1 which inhibits nuclear envelope expansion and nuclear elongation during the closed mitosis of fission yeast, and showed that its target is the β-subunit of fatty acid synthase. A point mutation in the dehydratase domain of Fas1 conferred in vivo and in vitro resistance to Cutin-1. Time-lapse photomicrography showed that the bulk of the chromosomes were only transiently separated during mitosis, and nucleoli separation was defective. Subsequently sister chromatids re-associated leading to chromosomal mis-segregation. These segregation defects were reduced when the nuclear volume was increased and were increased when the nuclear volume was reduced. We propose that there needs to be sufficient nuclear volume to allow the nuclear elongation necessary during a closed mitosis to take place for proper chromosome segregation, and that inhibition of fatty acid synthase compromises nuclear elongation and leads to defects in chromosomal segregation. Summary: Identification of a new fatty acid synthase inhibitor for nuclear division by a chemical genetic screen revealed a link between nuclear envelope expansion and faithful chromosome segregation in a closed mitosis.
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Affiliation(s)
- Ai Takemoto
- Laboratory of Yeast Genetics and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Shigehiro A Kawashima
- Laboratory of Chemistry and Cell Biology, Rockefeller University, New York, NY 10065, USA Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Juan-Juan Li
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, London NW1 2BE, UK
| | - Linda Jeffery
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, London NW1 2BE, UK
| | - Kenzo Yamatsugu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Olivier Elemento
- Department of Physiology and Biophysics, Institute for Computational Biomedicine, Weill Cornell Medical College, New York, NY 10021, USA
| | - Paul Nurse
- Laboratory of Yeast Genetics and Cell Biology, The Rockefeller University, New York, NY 10065, USA The Francis Crick Institute, Lincoln's Inn Fields Laboratories, London NW1 2BE, UK
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44
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Sec66-Dependent Regulation of Yeast Spindle-Pole Body Duplication Through Pom152. Genetics 2015; 201:1479-95. [PMID: 26510791 PMCID: PMC4676539 DOI: 10.1534/genetics.115.178012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 10/23/2015] [Indexed: 02/06/2023] Open
Abstract
In closed mitotic systems such as Saccharomyces cerevisiae, the nuclear envelope (NE) does not break down during mitosis, so microtubule-organizing centers such as the spindle-pole body (SPB) must be inserted into the NE to facilitate bipolar spindle formation and chromosome segregation. The mechanism of SPB insertion has been linked to NE insertion of nuclear pore complexes (NPCs) through a series of genetic and physical interactions between NPCs and SPB components. To identify new genes involved in SPB duplication and NE insertion, we carried out genome-wide screens for suppressors of deletion alleles of SPB components, including Mps3 and Mps2. In addition to the nucleoporins POM152 and POM34, we found that elimination of SEC66/SEC71/KAR7 suppressed lethality of cells lacking MPS2 or MPS3. Sec66 is a nonessential subunit of the Sec63 complex that functions together with the Sec61 complex in import of proteins into the endoplasmic reticulum (ER). Cells lacking Sec66 have reduced levels of Pom152 protein but not Pom34 or Ndc1, a shared component of the NPC and SPB. The fact that Sec66 but not other subunits of the ER translocon bypass deletion mutants in SPB genes suggests a specific role for Sec66 in the control of Pom152 levels. Based on the observation that sec66∆ does not affect the distribution of Ndc1 on the NE or Ndc1 binding to the SPB, we propose that Sec66-mediated regulation of Pom152 plays an NPC-independent role in the control of SPB duplication.
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Yang HJ, Asakawa H, Haraguchi T, Hiraoka Y. Nup132 modulates meiotic spindle attachment in fission yeast by regulating kinetochore assembly. J Cell Biol 2015; 211:295-308. [PMID: 26483559 PMCID: PMC4621824 DOI: 10.1083/jcb.201501035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 09/11/2015] [Indexed: 02/06/2023] Open
Abstract
The fission yeast nucleoporin Nup132 is required for timely assembly of outer kinetochore proteins during meiotic prophase and its depletion activates the spindle assembly checkpoint in meiosis I, suggesting a role in establishing monopolar spindle attachment through outer kinetochore reorganization at meiotic prophase. During meiosis, the kinetochore undergoes substantial reorganization to establish monopolar spindle attachment. In the fission yeast Schizosaccharomyces pombe, the KNL1–Spc7-Mis12-Nuf2 (KMN) complex, which constitutes the outer kinetochore, is disassembled during meiotic prophase and is reassembled before meiosis I. Here, we show that the nucleoporin Nup132 is required for timely assembly of the KMN proteins: In the absence of Nup132, Mis12 and Spc7 are precociously assembled at the centromeres during meiotic prophase. In contrast, Nuf2 shows timely dissociation and reappearance at the meiotic centromeres. We further demonstrate that depletion of Nup132 activates the spindle assembly checkpoint in meiosis I, possibly because of the increased incidence of erroneous spindle attachment at sister chromatids. These results suggest that precocious assembly of the kinetochores leads to the meiosis I defects observed in the nup132-disrupted mutant. Thus, we propose that Nup132 plays an important role in establishing monopolar spindle attachment at meiosis I through outer kinetochore reorganization at meiotic prophase.
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Affiliation(s)
- Hui-Ju Yang
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
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46
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Akera T, Goto Y, Sato M, Yamamoto M, Watanabe Y. Mad1 promotes chromosome congression by anchoring a kinesin motor to the kinetochore. Nat Cell Biol 2015; 17:1124-33. [PMID: 26258632 DOI: 10.1038/ncb3219] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 07/06/2015] [Indexed: 12/16/2022]
Abstract
For proper partitioning of genomes in mitosis, all chromosomes must be aligned at the spindle equator before the onset of anaphase. The spindle assembly checkpoint (SAC) monitors this process, generating a 'wait anaphase' signal at unattached kinetochores of misaligned chromosomes. However, the link between SAC activation and chromosome alignment is poorly understood. Here we show that Mad1, a core SAC component, plays a hitherto concealed role in chromosome alignment. Protein-protein interaction screening revealed that fission yeast Mad1 binds the plus-end-directed kinesin-5 motor protein Cut7 (Eg5 homologue), which is generally thought to promote spindle bipolarity. We demonstrate that Mad1 recruits Cut7 to kinetochores of misaligned chromosomes and promotes chromosome gliding towards the spindle equator. Similarly, human Mad1 recruits another kinetochore motor CENP-E, revealing that Mad1 is the conserved dual-function protein acting in SAC activation and chromosome gliding. Our results suggest that the mitotic checkpoint has co-evolved with a mechanism to drive chromosome congression.
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Affiliation(s)
- Takashi Akera
- Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Tokyo 113-0032, Japan.,Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Yayoi, Tokyo 113-0032, Japan
| | - Yuhei Goto
- Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Tokyo 113-0032, Japan.,Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Yayoi, Tokyo 113-0032, Japan
| | - Masamitsu Sato
- Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Yayoi, Tokyo 113-0032, Japan
| | - Masayuki Yamamoto
- Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Yayoi, Tokyo 113-0032, Japan
| | - Yoshinori Watanabe
- Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Tokyo 113-0032, Japan.,Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Yayoi, Tokyo 113-0032, Japan
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47
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Scheffler K, Minnes R, Fraisier V, Paoletti A, Tran PT. Microtubule minus end motors kinesin-14 and dynein drive nuclear congression in parallel pathways. ACTA ACUST UNITED AC 2015; 209:47-58. [PMID: 25869666 PMCID: PMC4395489 DOI: 10.1083/jcb.201409087] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Long-term imaging via microfluidic chambers shows that two minus end–directed motors, dynein and Klp2, work in parallel at distinct subcellular structures to promote efficient nuclear congression. Microtubules (MTs) and associated motors play a central role in nuclear migration, which is crucial for diverse biological functions including cell division, polarity, and sexual reproduction. In this paper, we report a dual mechanism underlying nuclear congression during fission yeast karyogamy upon mating of haploid cells. Using microfluidic chambers for long-term imaging, we captured the precise timing of nuclear congression and identified two minus end–directed motors operating in parallel in this process. Kinesin-14 Klp2 associated with MTs may cross-link and slide antiparallel MTs emanating from the two nuclei, whereas dynein accumulating at spindle pole bodies (SPBs) may pull MTs nucleated from the opposite SPB. Klp2-dependent nuclear congression proceeds at constant speed, whereas dynein accumulation results in an increase of nuclear velocity over time. Surprisingly, the light intermediate chain Dli1, but not dynactin, is required for this previously unknown function of dynein. We conclude that efficient nuclear congression depends on the cooperation of two minus end–directed motors.
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Affiliation(s)
- Kathleen Scheffler
- Centre de Recherche and BioImaging Cell and Tissue Core Facility of the Institut Curie (PICT-IBiSA), Institut Curie, F-75248 Paris, France Centre National de la Recherche Scientifique, Unite Mixte de Recherche 144, F-75248 Paris, France
| | - Refael Minnes
- Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Vincent Fraisier
- Centre de Recherche and BioImaging Cell and Tissue Core Facility of the Institut Curie (PICT-IBiSA), Institut Curie, F-75248 Paris, France Centre National de la Recherche Scientifique, Unite Mixte de Recherche 144, F-75248 Paris, France
| | - Anne Paoletti
- Centre de Recherche and BioImaging Cell and Tissue Core Facility of the Institut Curie (PICT-IBiSA), Institut Curie, F-75248 Paris, France Centre National de la Recherche Scientifique, Unite Mixte de Recherche 144, F-75248 Paris, France
| | - Phong T Tran
- Centre de Recherche and BioImaging Cell and Tissue Core Facility of the Institut Curie (PICT-IBiSA), Institut Curie, F-75248 Paris, France Centre National de la Recherche Scientifique, Unite Mixte de Recherche 144, F-75248 Paris, France Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104
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48
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The tethering of chromatin to the nuclear envelope supports nuclear mechanics. Nat Commun 2015; 6:7159. [PMID: 26074052 PMCID: PMC4490570 DOI: 10.1038/ncomms8159] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 04/10/2015] [Indexed: 12/23/2022] Open
Abstract
The nuclear lamina is thought to be the primary mechanical defence of the nucleus. However, the lamina is integrated within a network of lipids, proteins and chromatin; the interdependence of this network poses a challenge to defining the individual mechanical contributions of these components. Here, we isolate the role of chromatin in nuclear mechanics by using a system lacking lamins. Using novel imaging analyses, we observe that untethering chromatin from the inner nuclear membrane results in highly deformable nuclei in vivo, particularly in response to cytoskeletal forces. Using optical tweezers, we find that isolated nuclei lacking inner nuclear membrane tethers are less stiff than wild-type nuclei and exhibit increased chromatin flow, particularly in frequency ranges that recapitulate the kinetics of cytoskeletal dynamics. We suggest that modulating chromatin flow can define both transient and long-lived changes in nuclear shape that are biologically important and may be altered in disease. The mechanical properties of the metazoan nucleus can be influenced by the nuclear lamina. Here, Schreiner et al. show that untethering chromatin from the inner nuclear membrane results in highly deformable, softer nuclei, revealing an important role for chromatin in modulating nuclear mechanics.
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49
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Syrovatkina V, Tran PT. Loss of kinesin-14 results in aneuploidy via kinesin-5-dependent microtubule protrusions leading to chromosome cut. Nat Commun 2015; 6:7322. [PMID: 26031557 PMCID: PMC4720966 DOI: 10.1038/ncomms8322] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 04/27/2015] [Indexed: 11/11/2022] Open
Abstract
Aneuploidy – chromosome instability leading to incorrect chromosome number in dividing cells – can arise from defects in centrosome duplication, bipolar spindle formation, kinetochore-microtubule attachment, chromatid cohesion, mitotic checkpoint monitoring, or cytokinesis. As most tumors show some degree of aneuploidy, mechanistic understanding of these pathways has been an intense area of research to provide potential therapeutics. Here, we present a mechanism for aneuploidy in fission yeast based on spindle pole microtubule defocusing by loss of kinesin-14 Pkl1, leading to kinesin-5 Cut7-dependent aberrant long spindle microtubule minus end protrusions that push the properly segregated chromosomes to the site of cell division, resulting in chromosome cut at cytokinesis. Pkl1 localization and function at the spindle pole is mutually dependent on spindle pole-associated protein Msd1. This mechanism of aneuploidy bypasses the known spindle assembly checkpoint that monitors chromosome segregation.
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Affiliation(s)
- Viktoriya Syrovatkina
- Department of Cell and Developmental Biology, University of Pennsylvania, 421 Curie Boulevard, Room 1145, Philadelphia, Pennsylvania 19104, USA
| | - Phong T Tran
- 1] Department of Cell and Developmental Biology, University of Pennsylvania, 421 Curie Boulevard, Room 1145, Philadelphia, Pennsylvania 19104, USA [2] Institut Curie, PSL Research University, Paris F-75248, France [3] Centre National de la Recherche Scientifique, Unite Mixte de Recherche 144, Paris F-75248, France
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50
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Castagnetti S, Božič B, Svetina S. Mechanical and molecular basis for the symmetrical division of the fission yeast nuclear envelope. Phys Chem Chem Phys 2015; 17:15629-36. [PMID: 26024503 DOI: 10.1039/c5cp01243k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In fission yeast Schizosaccharomyces pombe, the nuclear envelope remains intact throughout mitosis and undergoes a series of symmetrical morphological changes when the spindle pole bodies (SPBs), embedded in the nuclear envelope, are pushed apart by elongating spindle microtubules. These symmetrical membrane shape transformations do not correspond to the shape behavior of an analogous system based on lipid vesicles. Here we report that the symmetry of the dividing fission yeast nucleus is ensured by SPB-chromosome attachments, as loss of kinetochore clustering in the vicinity of SPBs results in the formation of abnormal asymmetric shapes with long membrane tethers. We integrated these findings in a biophysical model, which explains the symmetry of the nuclear shapes on the basis of forces exerted by chromosomes clustered at SPBs on the extending nuclear envelope. Based on this analysis we conclude that the fission yeast nuclear envelope exhibits the same mechanical properties as simple lipid vesicles, but interactions with other cellular components, such as chromosomes, influence the nuclear shape during mitosis, allowing the formation of otherwise energetically unfavorable symmetrical dumbbell structures upon spindle elongation. The model allows us to explain the appearance of abnormal asymmetric shapes in fission yeast mutants with mis-segregated chromosomes as well as with altered nuclear membrane composition.
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Affiliation(s)
- Stefania Castagnetti
- UPMC Univ Paris 06, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanographique, 06230 Villefranche-sur-mer, France.
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