1
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Qi X, Liu Y, Peng Y, Fu Y, Fu Y, Yin L, Li X. UHRF1 promotes spindle assembly and chromosome congression by catalyzing EG5 polyubiquitination. J Cell Biol 2023; 222:e202210093. [PMID: 37728657 PMCID: PMC10510743 DOI: 10.1083/jcb.202210093] [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: 10/24/2022] [Revised: 05/18/2023] [Accepted: 08/24/2023] [Indexed: 09/21/2023] Open
Abstract
UHRF1 is an epigenetic coordinator bridging DNA methylation and histone modifications. Additionally, UHRF1 regulates DNA replication and cell cycle, and its deletion induces G1/S or G2/M cell cycle arrest. The roles of UHRF1 in the regulation of G2/M transition remain poorly understood. UHRF1 depletion caused chromosome misalignment, thereby inducing cell cycle arrest at mitotic metaphase, and these cells exhibited the defects of spindle geometry, prominently manifested as shorter spindles. Mechanistically, UHRF1 protein directly interacts with EG5, a kinesin motor protein, during mitosis. Furthermore, UHRF1 induced EG5 polyubiquitination at the site of K1034 and further promoted the interaction of EG5 with spindle assembly factor TPX2, thereby ensuring accurate EG5 distribution to the spindles during metaphase. Our study clarifies a novel UHRF1 function as a nuclear protein catalyzing EG5 polyubiquitination for proper spindle architecture and faithful genomic transmission, which is independent of its roles in epigenetic regulation and DNA damage repair inside the nucleus. These findings revealed a previously unknown mechanism of UHRF1 in controlling mitotic spindle architecture and chromosome behavior and provided mechanistic evidence for UHRF1 deletion-mediated G2/M arrest.
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Affiliation(s)
- Xuli Qi
- Department of Oncology, Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Molecular Radiation Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Youhong Liu
- Department of Oncology, Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Molecular Radiation Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Yuchong Peng
- Center for Clinical Precision Pharmacy, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China
- Key Specialty of Clinical Pharmacy, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China
- NMPA Key Laboratory for Technology Research and Evaluation of Pharmacovigilance, Guangdong Pharmaceutical University, Guangzhou, China
| | - Yuxin Fu
- Department of Oncology, Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Molecular Radiation Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Yongming Fu
- Center for Clinical Precision Pharmacy, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China
- Key Specialty of Clinical Pharmacy, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China
- NMPA Key Laboratory for Technology Research and Evaluation of Pharmacovigilance, Guangdong Pharmaceutical University, Guangzhou, China
| | - Linglong Yin
- Department of Oncology, Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Molecular Radiation Oncology, Xiangya Hospital, Central South University, Changsha, China
- Center for Clinical Precision Pharmacy, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China
- School of Clinical Pharmacy, Guangdong Pharmaceutical University, Guangzhou, China
| | - Xiong Li
- Center for Clinical Precision Pharmacy, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China
- Key Specialty of Clinical Pharmacy, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China
- NMPA Key Laboratory for Technology Research and Evaluation of Pharmacovigilance, Guangdong Pharmaceutical University, Guangzhou, China
- School of Clinical Pharmacy, Guangdong Pharmaceutical University, Guangzhou, China
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2
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Seitz BC, Mucelli X, Majano M, Wallis Z, Dodge AC, Carmona C, Durant M, Maynard S, Huang LS. Meiosis II spindle disassembly requires two distinct pathways. Mol Biol Cell 2023; 34:ar98. [PMID: 37436806 PMCID: PMC10551701 DOI: 10.1091/mbc.e23-03-0096] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 06/26/2023] [Accepted: 07/03/2023] [Indexed: 07/13/2023] Open
Abstract
During exit from meiosis II, cells undergo several structural rearrangements, including disassembly of the meiosis II spindles and cytokinesis. Each of these changes is regulated to ensure that they occur at the proper time. Previous studies have demonstrated that both SPS1, which encodes a STE20-family GCKIII kinase, and AMA1, which encodes a meiosis-specific activator of the Anaphase Promoting Complex, are required for both meiosis II spindle disassembly and cytokinesis in the budding yeast Saccharomyces cerevisiae. We examine the relationship between meiosis II spindle disassembly and cytokinesis and find that the meiosis II spindle disassembly failure in sps1Δ and ama1∆ cells is not the cause of the cytokinesis defect. We also see that the spindle disassembly defects in sps1Δ and ama1∆ cells are phenotypically distinct. We examined known microtubule-associated proteins Ase1, Cin8, and Bim1, and found that AMA1 is required for the proper loss of Ase1 and Cin8 on meiosis II spindles while SPS1 is required for Bim1 loss in meiosis II. Taken together, these data indicate that SPS1 and AMA1 promote distinct aspects of meiosis II spindle disassembly, and that both pathways are required for the successful completion of meiosis.
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Affiliation(s)
- Brian C. Seitz
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Xheni Mucelli
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Maira Majano
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Zoey Wallis
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Ashley C. Dodge
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Catherine Carmona
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Matthew Durant
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Sharra Maynard
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
| | - Linda S. Huang
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125
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3
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Luo J, Cao J, Chen C, Xie H. Emerging role of RNA acetylation modification ac4C in diseases: Current advances and future challenges. Biochem Pharmacol 2023; 213:115628. [PMID: 37247745 DOI: 10.1016/j.bcp.2023.115628] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/20/2023] [Accepted: 05/23/2023] [Indexed: 05/31/2023]
Abstract
The oldest known highly conserved modification of RNA, N4-acetylcytidine, is widely distributed from archaea to eukaryotes and acts as a posttranscriptional chemical modification of RNA, contributing to the correct reading of specific nucleotide sequences during translation, stabilising mRNA and improving transcription efficiency. Yeast Kre33 and human NAT10, the only known authors of ac4C, modify tRNA with the help of the Tan1/THUMPD1 adapter to stabilise its structure. Currently, the mRNA for N4-acetylcytidine (ac4C), catalysed by NAT10 (N-acetyltransferase 10), has been implicated in a variety of human diseases, particularly cancer. This article reviews advances in the study of ac4C modification of RNA and the ac4C-related gene NAT10 in normal physiological cell development, cancer, premature disease and viral infection and discusses its therapeutic promise and future research challenges.
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Affiliation(s)
- Jie Luo
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China
| | - Jingsong Cao
- Department of Endocrinology and Metabolism, The First Affiliated Hospital, Institute of Clinical Medicine, University of South China, Hengyang 421001, China
| | - Cong Chen
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China
| | - Haitao Xie
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China.
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4
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Campos A, Ramos F, Iglesias L, Delgado C, Merino E, Esperilla-Muñoz A, Correa-Bordes J, Clemente-Blanco A. Cdc14 phosphatase counteracts Cdk-dependent Dna2 phosphorylation to inhibit resection during recombinational DNA repair. Nat Commun 2023; 14:2738. [PMID: 37173316 PMCID: PMC10182099 DOI: 10.1038/s41467-023-38417-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Cyclin-dependent kinase (Cdk) stimulates resection of DNA double-strand breaks ends to generate single-stranded DNA (ssDNA) needed for recombinational DNA repair. Here we show in Saccharomyces cerevisiae that lack of the Cdk-counteracting phosphatase Cdc14 produces abnormally extended resected tracts at the DNA break ends, involving the phosphatase in the inhibition of resection. Over-resection in the absence of Cdc14 activity is bypassed when the exonuclease Dna2 is inactivated or when its Cdk consensus sites are mutated, indicating that the phosphatase restrains resection by acting through this nuclease. Accordingly, mitotically activated Cdc14 promotes Dna2 dephosphorylation to exclude it from the DNA lesion. Cdc14-dependent resection inhibition is essential to sustain DNA re-synthesis, thus ensuring the appropriate length, frequency, and distribution of the gene conversion tracts. These results establish a role for Cdc14 in controlling the extent of resection through Dna2 regulation and demonstrate that the accumulation of excessively long ssDNA affects the accurate repair of the broken DNA by homologous recombination.
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Affiliation(s)
- Adrián Campos
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, Salamanca, Spain
| | - Facundo Ramos
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, Salamanca, Spain
| | - Lydia Iglesias
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, Salamanca, Spain
| | - Celia Delgado
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, Salamanca, Spain
| | - Eva Merino
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, Salamanca, Spain
| | | | - Jaime Correa-Bordes
- Departamento de Ciencias Biomédicas, Universidad de Extremadura, Badajoz, Spain
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, Salamanca, Spain.
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5
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Zucca F, Visintin C, Li J, Gygi SP, Visintin R. APC/CCdc20-mediated degradation of Clb4 prompts astral microtubule stabilization at anaphase onset. J Cell Biol 2022; 222:213563. [PMID: 36269172 PMCID: PMC9595209 DOI: 10.1083/jcb.202203089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 08/12/2022] [Accepted: 10/05/2022] [Indexed: 11/22/2022] Open
Abstract
Key for accurate chromosome partitioning to the offspring is the ability of mitotic spindle microtubules to respond to different molecular signals and remodel their dynamics accordingly. Spindle microtubules are conventionally divided into three classes: kinetochore, interpolar, and astral microtubules (kMTs, iMTs, and aMTs, respectively). Among all, aMT regulation remains elusive. Here, we show that aMT dynamics are tightly regulated. aMTs remain unstable up to metaphase and are stabilized at anaphase onset. This switch in aMT dynamics, important for proper spindle orientation, specifically requires the degradation of the mitotic cyclin Clb4 by the Anaphase Promoting Complex bound to its activator subunit Cdc20 (APC/CCdc20). These data highlight a unique role for mitotic cyclin Clb4 in controlling aMT regulating factors, of which Kip2 is a prime candidate, provide a framework to understand aMT regulation in vertebrates, and uncover mechanistic principles of how the APC/CCdc20 choreographs the timing of late mitotic events by sequentially impacting on the three classes of spindle microtubules.
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Affiliation(s)
- Federico Zucca
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Milan, Italy
| | - Clara Visintin
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Milan, Italy
| | - Jiaming Li
- Department of Cell Biology, Harvard Medical School, Boston, MA
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA
| | - Rosella Visintin
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Milan, Italy,Correspondence to Rosella Visintin:
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6
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Deshpande O, de-Carvalho J, Vieira DV, Telley IA. Astral microtubule cross-linking safeguards uniform nuclear distribution in the Drosophila syncytium. J Cell Biol 2022; 221:212810. [PMID: 34766978 PMCID: PMC8594625 DOI: 10.1083/jcb.202007209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/24/2021] [Accepted: 10/20/2021] [Indexed: 12/16/2022] Open
Abstract
The early insect embryo develops as a multinucleated cell distributing the genome uniformly to the cell cortex. Mechanistic insight for nuclear positioning beyond cytoskeletal requirements is missing. Contemporary hypotheses propose actomyosin-driven cytoplasmic movement transporting nuclei or repulsion of neighbor nuclei driven by microtubule motors. Here, we show that microtubule cross-linking by Feo and Klp3A is essential for nuclear distribution and internuclear distance maintenance in Drosophila. Germline knockdown causes irregular, less-dense nuclear delivery to the cell cortex and smaller distribution in ex vivo embryo explants. A minimal internuclear distance is maintained in explants from control embryos but not from Feo-inhibited embryos, following micromanipulation-assisted repositioning. A dimerization-deficient Feo abolishes nuclear separation in embryo explants, while the full-length protein rescues the genetic knockdown. We conclude that Feo and Klp3A cross-linking of antiparallel microtubule overlap generates a length-regulated mechanical link between neighboring microtubule asters. Enabled by a novel experimental approach, our study illuminates an essential process of embryonic multicellularity.
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Affiliation(s)
- Ojas Deshpande
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Diana V Vieira
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
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7
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Norell S, Ortiz J, Lechner J. Slk19 enhances cross-linking of microtubules by Ase1 and Stu1. Mol Biol Cell 2021; 32:ar22. [PMID: 34495712 PMCID: PMC8693956 DOI: 10.1091/mbc.e21-05-0279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The Saccharomyces cerevisiae protein Slk19 has been shown to localize to kinetochores throughout mitosis and to the spindle midzone in anaphase. However, Slk19 clearly also has an important role for spindle formation and stabilization in prometaphase and metaphase, albeit this role is unresolved. Here we show that Slk19’s localization to metaphase spindles in vivo and to microtubules (MTs) in vitro depends on the MT cross-linking protein Ase1 and the MT cross-linking and stabilizing protein Stu1. By analyzing a slk19 mutant that specifically fails to localize to spindles and MTs, we surprisingly found that the presence of Slk19 amplified the amount of Ase1 strongly and that of Stu1 moderately at the metaphase spindle in vivo and at MTs in vitro. Furthermore, Slk19 markedly enhanced the cross-linking of MTs in vitro when added together with Ase1 or Stu1. We therefore suggest that Slk19 recruits additional Ase1 and Stu1 to the interpolar MTs (ipMTs) of metaphase spindles and thus increases their cross-linking and stabilization. This is in agreement with our observation that cells with defective Slk19 localization exhibit shorter metaphase spindles, an increased number of unaligned nuclear MTs, and most likely reduced ipMT overlaps.
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Affiliation(s)
- Sarina Norell
- Biochemie-Zentrum der Universität Heidelberg, INF 328, 69120 Heidelberg, Germany
| | - Jennifer Ortiz
- Biochemie-Zentrum der Universität Heidelberg, INF 328, 69120 Heidelberg, Germany
| | - Johannes Lechner
- Biochemie-Zentrum der Universität Heidelberg, INF 328, 69120 Heidelberg, Germany
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8
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Asthana J, Cade NI, Normanno D, Lim WM, Surrey T. Gradual compaction of the central spindle decreases its dynamicity in PRC1 and EB1 gene-edited cells. Life Sci Alliance 2021; 4:4/12/e202101222. [PMID: 34580180 PMCID: PMC8500333 DOI: 10.26508/lsa.202101222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 11/24/2022] Open
Abstract
Although different anaphase proteins bind with characteristically different strength to the central spindle, the overall central spindle dynamicity slows down as mitosis proceeds. During mitosis, the spindle undergoes morphological and dynamic changes. It reorganizes at the onset of the anaphase when the antiparallel bundler PRC1 accumulates and recruits central spindle proteins to the midzone. Little is known about how the dynamic properties of the central spindle change during its morphological changes in human cells. Using gene editing, we generated human cells that express from their endogenous locus fluorescent PRC1 and EB1 to quantify their native spindle distribution and binding/unbinding turnover. EB1 plus end tracking revealed a general slowdown of microtubule growth, whereas PRC1, similar to its yeast orthologue Ase1, binds increasingly strongly to compacting antiparallel microtubule overlaps. KIF4A and CLASP1 bind more dynamically to the central spindle, but also show slowing down turnover. These results show that the central spindle gradually becomes more stable during mitosis, in agreement with a recent “bundling, sliding, and compaction” model of antiparallel midzone bundle formation in the central spindle during late mitosis.
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Affiliation(s)
- Jayant Asthana
- The Francis Crick Institute, London, UK.,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | | | - Davide Normanno
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Wei Ming Lim
- The Francis Crick Institute, London, UK.,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Thomas Surrey
- The Francis Crick Institute, London, UK .,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
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9
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Goldstein-Levitin A, Pandey H, Allhuzaeel K, Kass I, Gheber L. Intracellular functions and motile properties of bi-directional kinesin-5 Cin8 are regulated by neck linker docking. eLife 2021; 10:71036. [PMID: 34387192 PMCID: PMC8456603 DOI: 10.7554/elife.71036] [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: 06/06/2021] [Accepted: 07/13/2021] [Indexed: 12/03/2022] Open
Abstract
In this study, we analyzed intracellular functions and motile properties of neck-linker (NL) variants of the bi-directional S. cerevisiae kinesin-5 motor, Cin8. We also examined – by modeling – the configuration of H-bonds during NL docking. Decreasing the number of stabilizing H-bonds resulted in partially functional variants, as long as a conserved backbone H-bond at the N-latch position (proposed to stabilize the docked conformation of the NL) remained intact. Elimination of this conserved H-bond resulted in production of a non-functional Cin8 variant. Surprisingly, additional H-bond stabilization of the N-latch position, generated by replacement of the NL of Cin8 by sequences of the plus-end directed kinesin-5 Eg5, also produced a nonfunctional variant. In that variant, a single replacement of N-latch asparagine with glycine, as present in Cin8, eliminated the additional H-bond stabilization and rescued the functional defects. We conclude that exact N-latch stabilization during NL docking is critical for the function of bi-directional kinesin-5 Cin8.
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Affiliation(s)
| | - Himanshu Pandey
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Kanary Allhuzaeel
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Itamar Kass
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,InterX LTD, Ramat-Gan, Israel
| | - Larisa Gheber
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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10
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Mengoli V, Jonak K, Lyzak O, Lamb M, Lister LM, Lodge C, Rojas J, Zagoriy I, Herbert M, Zachariae W. Deprotection of centromeric cohesin at meiosis II requires APC/C activity but not kinetochore tension. EMBO J 2021; 40:e106812. [PMID: 33644894 PMCID: PMC8013787 DOI: 10.15252/embj.2020106812] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 01/03/2023] Open
Abstract
Genome haploidization involves sequential loss of cohesin from chromosome arms and centromeres during two meiotic divisions. At centromeres, cohesin's Rec8 subunit is protected from separase cleavage at meiosis I and then deprotected to allow its cleavage at meiosis II. Protection of centromeric cohesin by shugoshin-PP2A seems evolutionarily conserved. However, deprotection has been proposed to rely on spindle forces separating the Rec8 protector from cohesin at metaphase II in mammalian oocytes and on APC/C-dependent destruction of the protector at anaphase II in yeast. Here, we have activated APC/C in the absence of sister kinetochore biorientation at meiosis II in yeast and mouse oocytes, and find that bipolar spindle forces are dispensable for sister centromere separation in both systems. Furthermore, we show that at least in yeast, protection of Rec8 by shugoshin and inhibition of separase by securin are both required for the stability of centromeric cohesin at metaphase II. Our data imply that related mechanisms preserve the integrity of dyad chromosomes during the short metaphase II of yeast and the prolonged metaphase II arrest of mammalian oocytes.
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Affiliation(s)
- Valentina Mengoli
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
- Present address:
Institute for Research in BiomedicineUniversità della Svizzera ItalianaBellinzonaSwitzerland
| | - Katarzyna Jonak
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Oleksii Lyzak
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Mahdi Lamb
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Lisa M Lister
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Chris Lodge
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Julie Rojas
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Ievgeniia Zagoriy
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
- Present address:
EMBL HeidelbergHeidelbergGermany
| | - Mary Herbert
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Wolfgang Zachariae
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
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11
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Kornakov N, Möllers B, Westermann S. The EB1-Kinesin-14 complex is required for efficient metaphase spindle assembly and kinetochore bi-orientation. J Cell Biol 2021; 219:211447. [PMID: 33044553 PMCID: PMC7545359 DOI: 10.1083/jcb.202003072] [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] [Received: 03/12/2020] [Revised: 07/28/2020] [Accepted: 09/10/2020] [Indexed: 12/28/2022] Open
Abstract
Kinesin-14s are conserved molecular motors required for high-fidelity chromosome segregation, but their specific contributions to spindle function have not been fully defined. Here, we show that key functions of budding yeast Kinesin-14 Cik1-Kar3 are accomplished in a complex with Bim1 (yeast EB1). Genetic complementation of mitotic phenotypes identifies a novel KLTF peptide motif in the Cik1 N-terminus. We show that this motif is one element of a tripartite binding interface required to form a high-affinity Bim1–Cik1-Kar3 complex. Lack of Bim1-binding by Cik1-Kar3 delays cells in mitosis and impairs microtubule bundle organization and dynamics. Conversely, constitutive targeting of Cik1-Kar3 to microtubule plus ends induces the formation of nuclear microtubule bundles. Cells lacking the Bim1–Cik1-Kar3 complex rely on the conserved microtubule bundler Ase1/PRC1 for metaphase spindle organization, and simultaneous loss of plus-end targeted Kar3 and Ase1 is lethal. Our results reveal the contributions of an EB1–Kinesin-14 complex for spindle formation as a prerequisite for efficient kinetochore clustering and bi-orientation.
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Affiliation(s)
- Nikolay Kornakov
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Bastian Möllers
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Stefan Westermann
- Department of Molecular Genetics, Faculty of Biology, Center of Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
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12
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Thomas EC, Ismael A, Moore JK. Ase1 domains dynamically slow anaphase spindle elongation and recruit Bim1 to the midzone. Mol Biol Cell 2020; 31:2733-2747. [PMID: 32997572 PMCID: PMC7927185 DOI: 10.1091/mbc.e20-07-0493-t] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
How cells regulate microtubule cross-linking activity to control the rate and duration of spindle elongation during anaphase is poorly understood. In this study, we test the hypothesis that PRC1/Ase1 proteins use distinct microtubule-binding domains to control the spindle elongation rate. Using the budding yeast Ase1, we identify unique contributions for the spectrin and carboxy-terminal domains during different phases of spindle elongation. We show that the spectrin domain uses conserved basic residues to promote the recruitment of Ase1 to the midzone before anaphase onset and slow spindle elongation during early anaphase. In contrast, a partial Ase1 carboxy-terminal truncation fails to form a stable midzone in late anaphase, produces higher elongation rates after early anaphase, and exhibits frequent spindle collapses. We find that the carboxy-terminal domain interacts with the plus-end tracking protein EB1/Bim1 and recruits Bim1 to the midzone to maintain midzone length. Overall, our results suggest that the Ase1 domains provide cells with a modular system to tune midzone activity and control elongation rates.
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Affiliation(s)
- Ezekiel C Thomas
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Amber Ismael
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045.,Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
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13
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Wen Z, Zhu H, Zhang A, Lin J, Zhang G, Liu D, Xiao Y, Ye C, Sun D, Wu B, Zhang J, Gao J. Cdc14a has a role in spermatogenesis, sperm maturation and male fertility. Exp Cell Res 2020; 395:112178. [PMID: 32679235 DOI: 10.1016/j.yexcr.2020.112178] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 07/07/2020] [Accepted: 07/11/2020] [Indexed: 11/29/2022]
Abstract
Cdc14a is an evolutionarily conserved dual-specific protein phosphatase, and it plays different roles in different organisms. Cdc14a mutations in human have been reported to cause male infertility, while the specific role of Cdc14a in regulation of the male reproductive system remains elusive. In the present study, we established a knockout mouse model to study the function of Cdc14a in male reproductive system. Cdc14a-/- male mice were subfertile and they could only produce very few offspring. The number of sperm was decreased, the sperm motility was impaired, and the proportion of sperm with abnormal morphology was elevated in Cdc14a-/- mice. When we mated Cdc14a-/- male mice with wild-type (WT) female mice, fertilized eggs could be found in female fallopian tubes, however, the majority of these embryos died during development. Some empty spaces were observed in seminiferous tubule of Cdc14a-/- testes. Compared with WT male mice, the proportions of pachytene spermatocytes were increased and germ cells stained with γH2ax were decreased in Cdc14a-/- male mice, indicating that knockout of Cdc14a inhibited meiotic initiation. Subsequently, we analyzed the expression levels of some substrate proteins of Cdc14a, including Cdc25a, Wee1, and PR-Set7, and compared those with WT testes, in which the expression levels of these proteins were significantly increased in Cdc14a-/- testes. Our results revealed that Cdc14a-/- male mice are highly subfertile, and Cdc14a is essential for normal spermatogenesis and sperm function.
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Affiliation(s)
- Zongzhuang Wen
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Haixia Zhu
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Aizhen Zhang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Jing Lin
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Guangkai Zhang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Dongyue Liu
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Yu Xiao
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Chao Ye
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China
| | - Daqing Sun
- Department of Pediatric Surgery, Tianjin Medical University General Hospital, Tianjin, 300041, PR China.
| | - Bin Wu
- Department of Reproductive Medicine, Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250100, PR China.
| | - Jian Zhang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China.
| | - Jiangang Gao
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, 250100, PR China.
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14
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Braun M, Diez S, Lansky Z. Cytoskeletal organization through multivalent interactions. J Cell Sci 2020; 133:133/12/jcs234393. [PMID: 32540925 DOI: 10.1242/jcs.234393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cytoskeleton consists of polymeric protein filaments with periodic lattices displaying identical binding sites, which establish a multivalent platform for the binding of a plethora of filament-associated ligand proteins. Multivalent ligand proteins can tether themselves to the filaments through one of their binding sites, resulting in an enhanced reaction kinetics for the remaining binding sites. In this Opinion, we discuss a number of cytoskeletal phenomena underpinned by such multivalent interactions, namely (1) generation of entropic forces by filament crosslinkers, (2) processivity of molecular motors, (3) spatial sorting of proteins, and (4) concentration-dependent unbinding of filament-associated proteins. These examples highlight that cytoskeletal filaments constitute the basis for the formation of microenvironments, which cytoskeletal ligand proteins can associate with and, once engaged, can act within at altered reaction kinetics. We thus argue that multivalency is one of the properties crucial for the functionality of the cytoskeleton.
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Affiliation(s)
- Marcus Braun
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, 25250 Vestec, Prague West, Czech Republic
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden 01307, Germany .,Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden 01307, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
| | - Zdenek Lansky
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, 25250 Vestec, Prague West, Czech Republic
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15
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The Multiple Roles of the Cdc14 Phosphatase in Cell Cycle Control. Int J Mol Sci 2020; 21:ijms21030709. [PMID: 31973188 PMCID: PMC7038166 DOI: 10.3390/ijms21030709] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 12/20/2022] Open
Abstract
The Cdc14 phosphatase is a key regulator of mitosis in the budding yeast Saccharomyces cerevisiae. Cdc14 was initially described as playing an essential role in the control of cell cycle progression by promoting mitotic exit on the basis of its capacity to counteract the activity of the cyclin-dependent kinase Cdc28/Cdk1. A compiling body of evidence, however, has later demonstrated that this phosphatase plays other multiple roles in the regulation of mitosis at different cell cycle stages. Here, we summarize our current knowledge about the pivotal role of Cdc14 in cell cycle control, with a special focus in the most recently uncovered functions of the phosphatase.
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16
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Leary A, Sim S, Nazarova E, Shulist K, Genthial R, Yang SK, Bui KH, Francois P, Vogel J. Successive Kinesin-5 Microtubule Crosslinking and Sliding Promote Fast, Irreversible Formation of a Stereotyped Bipolar Spindle. Curr Biol 2019; 29:3825-3837.e3. [DOI: 10.1016/j.cub.2019.09.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 07/24/2019] [Accepted: 09/12/2019] [Indexed: 12/13/2022]
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17
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Julius J, Peng J, McCulley A, Caridi C, Arnak R, See C, Nugent CI, Feng W, Bachant J. Inhibition of spindle extension through the yeast S phase checkpoint is coupled to replication fork stability and the integrity of centromeric DNA. Mol Biol Cell 2019; 30:2771-2789. [PMID: 31509480 PMCID: PMC6789157 DOI: 10.1091/mbc.e19-03-0156] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Budding yeast treated with hydroxyurea (HU) activate the S phase checkpoint kinase Rad53, which prevents DNA replication forks from undergoing aberrant structural transitions and nuclease processing. Rad53 is also required to prevent premature extension of the mitotic spindle that assembles during a HU-extended S phase. Here we present evidence that checkpoint restraint of spindle extension is directly coupled to Rad53 control of replication fork stability. In budding yeast, centromeres are flanked by replication origins that fire in early S phase. Mutations affecting the Zn2+-finger of Dbf4, an origin activator, preferentially reduce centromere-proximal origin firing in HU, corresponding with suppression of rad53 spindle extension. Inactivating Exo1 nuclease or displacing centromeres from origins provides a similar suppression. Conversely, short-circuiting Rad53 targeting of Dbf4, Sld3, and Dun1, substrates contributing to fork stability, induces spindle extension. These results reveal spindle extension in HU-treated rad53 mutants is a consequence of replication fork catastrophes at centromeres. When such catastrophes occur, centromeres become susceptible to nucleases, disrupting kinetochore function and spindle force balancing mechanisms. At the same time, our data indicate centromere duplication is not required to stabilize S phase spindle structure, leading us to propose a model for how monopolar kinetochore-spindle attachments may contribute to spindle force balance in HU.
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Affiliation(s)
- Jeff Julius
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Jie Peng
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Andrew McCulley
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Chris Caridi
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Remigiusz Arnak
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Colby See
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Constance I Nugent
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Jeff Bachant
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
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18
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She ZY, Wei YL, Lin Y, Li YL, Lu MH. Mechanisms of the Ase1/PRC1/MAP65 family in central spindle assembly. Biol Rev Camb Philos Soc 2019; 94:2033-2048. [PMID: 31343816 DOI: 10.1111/brv.12547] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 06/27/2019] [Accepted: 07/03/2019] [Indexed: 01/08/2023]
Abstract
During cytokinesis, the organization of the spindle midzone and chromosome segregation is controlled by the central spindle, a microtubule cytoskeleton containing kinesin motors and non-motor microtubule-associated proteins. The anaphase spindle elongation 1/protein regulator of cytokinesis 1/microtubule associated protein 65 (Ase1/PRC1/MAP65) family of microtubule-bundling proteins are key regulators of central spindle assembly, mediating microtubule crosslinking and spindle elongation in the midzone. Ase1/PRC1/MAP65 serves as a complex regulatory platform for the recruitment of other midzone proteins at the spindle midzone. Herein, we summarize recent advances in understanding of the structural domains and molecular kinetics of the Ase1/PRC1/MAP65 family. We summarize the regulatory network involved in post-translational modifications of Ase1/PRC1 by cyclin-dependent kinase 1 (Cdk1), cell division cycle 14 (Cdc14) and Polo-like kinase 1 (Plk1) and also highlight multiple functions of Ase1/PRC1 in central spindle organization, spindle elongation and cytokinesis during cell division.
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Affiliation(s)
- Zhen-Yu She
- Department of Cell Biology and Genetics/Center for Cell and Developmental Biology, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350108, China
| | - Ya-Lan Wei
- Department of Cell Biology and Genetics/Center for Cell and Developmental Biology, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350108, China
| | - Yang Lin
- Department of Cell Biology and Genetics/Center for Cell and Developmental Biology, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350108, China
| | - Yue-Ling Li
- Department of Cell Biology and Genetics/Center for Cell and Developmental Biology, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350108, China
| | - Ming-Hui Lu
- Department of Cell Biology and Genetics/Center for Cell and Developmental Biology, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350108, China
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19
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Ayra-Plasencia J, Machín F. DNA double-strand breaks in telophase lead to coalescence between segregated sister chromatid loci. Nat Commun 2019; 10:2862. [PMID: 31253793 PMCID: PMC6598993 DOI: 10.1038/s41467-019-10742-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 05/30/2019] [Indexed: 12/24/2022] Open
Abstract
DNA double strand breaks (DSBs) pose a high risk for genome integrity. Cells repair DSBs through homologous recombination (HR) when a sister chromatid is available. HR is upregulated by the cycling dependent kinase (CDK) despite the paradox of telophase, where CDK is high but a sister chromatid is not nearby. Here we study in the budding yeast the response to DSBs in telophase, and find they activate the DNA damage checkpoint (DDC), leading to a telophase-to-G1 delay. Outstandingly, we observe a partial reversion of sister chromatid segregation, which includes approximation of segregated material, de novo formation of anaphase bridges, and coalescence between sister loci. We finally show that DSBs promote a massive change in the dynamics of telophase microtubules (MTs), together with dephosphorylation and relocalization of kinesin-5 Cin8. We propose that chromosome segregation is not irreversible and that DSB repair using the sister chromatid is possible in telophase.
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Affiliation(s)
- Jessel Ayra-Plasencia
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
- Escuela de Doctorado y Estudios de Posgrado, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
| | - Félix Machín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain.
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, Santa Cruz de Tenerife, Spain.
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20
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Zhu Y, Tan W, Lee WL. An in vitro Microscopy-based Assay for Microtubule-binding and Microtubule-crosslinking by Budding Yeast Microtubule-associated Protein. Bio Protoc 2018; 8:e3110. [PMID: 30733975 DOI: 10.21769/bioprotoc.3110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In this protocol, we describe a simple microscopy-based method to assess the interaction of a microtubule-associated protein (MAP) with microtubules. The interaction between MAP and microtubules is typically assessed by a co-sedimentation assay, which measures the amount of MAP that co-pellets with microtubules by centrifugation, followed by SDS-PAGE analysis of the supernatant and pellet fractions. However, MAPs that form large oligomers tend to pellet on their own during the centrifugation step, making it difficult to assess co-sedimentation. Here we describe a microscopy-based assay that measures microtubule binding by direct visualization using fluorescently-labeled MAP, solving the limitations of the co-sedimentation assay. Additionally, we recently reported quantification of microtubule bundling by measuring the thickness of individual microtubule structures observed in the microscopy-based assay, making the protocol more advantageous than the traditional microtubule co-pelleting assay.
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Affiliation(s)
- Yili Zhu
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Weimin Tan
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Wei-Lih Lee
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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21
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Kataria M, Mouilleron S, Seo MH, Corbi-Verge C, Kim PM, Uhlmann F. A PxL motif promotes timely cell cycle substrate dephosphorylation by the Cdc14 phosphatase. Nat Struct Mol Biol 2018; 25:1093-1102. [PMID: 30455435 PMCID: PMC6292506 DOI: 10.1038/s41594-018-0152-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/08/2018] [Indexed: 11/08/2022]
Abstract
The cell division cycle consists of a series of temporally ordered events. Cell cycle kinases and phosphatases provide key regulatory input, but how the correct substrate phosphorylation and dephosphorylation timing is achieved is incompletely understood. Here we identify a PxL substrate recognition motif that instructs dephosphorylation by the budding yeast Cdc14 phosphatase during mitotic exit. The PxL motif was prevalent in Cdc14-binding peptides enriched in a phage display screen of native disordered protein regions. PxL motif removal from the Cdc14 substrate Cbk1 delays its dephosphorylation, whereas addition of the motif advances dephosphorylation of otherwise late Cdc14 substrates. Crystal structures of Cdc14 bound to three PxL motif substrate peptides provide a molecular explanation for PxL motif recognition on the phosphatase surface. Our results illustrate the sophistication of phosphatase-substrate interactions and identify them as an important determinant of ordered cell cycle progression.
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Affiliation(s)
- Meghna Kataria
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
- University College London Cancer Institute, London, UK
| | - Stephane Mouilleron
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, UK
| | - Moon-Hyeong Seo
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Natural Constituents Research Center, Korea Institute of Science and Technology, Gangneung, Republic of Korea
| | - Carles Corbi-Verge
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Philip M Kim
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Departments of Molecular Genetics and Computer Science, University of Toronto, Toronto, Ontario, Canada
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK.
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22
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She1 affects dynein through direct interactions with the microtubule and the dynein microtubule-binding domain. Nat Commun 2017; 8:2151. [PMID: 29247176 PMCID: PMC5732302 DOI: 10.1038/s41467-017-02004-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/31/2017] [Indexed: 01/31/2023] Open
Abstract
Cytoplasmic dynein is an enormous minus end-directed microtubule motor. Rather than existing as bare tracks, microtubules are bound by numerous microtubule-associated proteins (MAPs) that have the capacity to affect various cellular functions, including motor-mediated transport. One such MAP is She1, a dynein effector that polarizes dynein-mediated spindle movements in budding yeast. Here, we characterize the molecular basis by which She1 affects dynein, providing the first such insight into which a MAP can modulate motor motility. We find that She1 affects the ATPase rate, microtubule-binding affinity, and stepping behavior of dynein, and that microtubule binding by She1 is required for its effects on dynein motility. Moreover, we find that She1 directly contacts the microtubule-binding domain of dynein, and that their interaction is sensitive to the nucleotide-bound state of the motor. Our data support a model in which simultaneous interactions between the microtubule and dynein enables She1 to directly affect dynein motility. Dynein is a microtubule motor the motility of which is affected by the microtubule-associated protein She1. Here, the authors show that She1 alters dynein stepping behavior and increases its microtubule affinity through simultaneous interactions with the microtubule and dynein microtubule binding domain.
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23
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Changes in microtubule overlap length regulate kinesin-14-driven microtubule sliding. Nat Chem Biol 2017; 13:1245-1252. [PMID: 29035362 PMCID: PMC5700410 DOI: 10.1038/nchembio.2495] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 09/11/2017] [Indexed: 01/01/2023]
Abstract
Microtubule-crosslinking motor proteins, which slide antiparallel
microtubules, are required for remodeling of microtubule networks. Hitherto, all
microtubule-crosslinking motors have been shown to slide microtubules at
constant velocity until no overlap between the microtubules remains, leading to
breakdown of the initial microtubule geometry. Here, we show in
vitro that the sliding velocity of microtubules, driven by human
kinesin-14, HSET, decreases when microtubules start to slide apart, resulting in
the maintenance of finite-length microtubule overlaps. We quantitatively explain
this feedback by the local interaction kinetics of HSET with overlapping
microtubules, causing retention of HSET in shortening overlaps. Consequently,
the increased HSET density in the overlaps leads to a density-dependent decrease
in sliding velocity and the generation of an entropic force antagonizing the
force exerted by the motors. Our results demonstrate that a spatial arrangement
of microtubules can regulate the collective action of molecular motors through
local alteration of their individual interaction kinetics.
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24
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Vukušić K, Buđa R, Bosilj A, Milas A, Pavin N, Tolić IM. Microtubule Sliding within the Bridging Fiber Pushes Kinetochore Fibers Apart to Segregate Chromosomes. Dev Cell 2017; 43:11-23.e6. [PMID: 29017027 PMCID: PMC5637169 DOI: 10.1016/j.devcel.2017.09.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/21/2017] [Accepted: 09/13/2017] [Indexed: 01/06/2023]
Abstract
During cell division, mitotic spindle microtubules segregate chromosomes by exerting forces on kinetochores. What forces drive chromosome segregation in anaphase remains a central question. The current model for anaphase in human cells includes shortening of kinetochore fibers and separation of spindle poles. Both processes require kinetochores to be linked with the poles. Here we show, by combining laser ablation, photoactivation, and theoretical modeling, that kinetochores can separate without any attachment to one spindle pole. This separation requires the bridging fiber, a microtubule bundle that connects sister kinetochore fibers. Bridging fiber microtubules in intact spindles slide apart with kinetochore fibers, indicating strong crosslinks between them. We conclude that sliding of microtubules within the bridging fibers drives pole separation and pushes kinetochore fibers poleward by the friction of passive crosslinks between these fibers. Thus, sliding within the bridging fiber works together with the shortening of kinetochore fibers to segregate chromosomes.
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Affiliation(s)
- Kruno Vukušić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Renata Buđa
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Agneza Bosilj
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia
| | - Ana Milas
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Nenad Pavin
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia.
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
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25
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Goldstein A, Siegler N, Goldman D, Judah H, Valk E, Kõivomägi M, Loog M, Gheber L. Three Cdk1 sites in the kinesin-5 Cin8 catalytic domain coordinate motor localization and activity during anaphase. Cell Mol Life Sci 2017; 74:3395-3412. [PMID: 28455557 PMCID: PMC11107736 DOI: 10.1007/s00018-017-2523-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 12/22/2022]
Abstract
The bipolar kinesin-5 motors perform essential functions in mitotic spindle dynamics. We previously demonstrated that phosphorylation of at least one of the Cdk1 sites in the catalytic domain of the Saccharomyces cerevisiae kinesin-5 Cin8 (S277, T285, S493) regulates its localization to the anaphase spindle. The contribution of these three sites to phospho-regulation of Cin8, as well as the timing of such contributions, remains unknown. Here, we examined the function and spindle localization of phospho-deficient (serine/threonine to alanine) and phospho-mimic (serine/threonine to aspartic acid) Cin8 mutants. In vitro, the three Cdk1 sites undergo phosphorylation by Clb2-Cdk1. In cells, phosphorylation of Cin8 affects two aspects of its localization to the anaphase spindle, translocation from the spindle-pole bodies (SPBs) region to spindle microtubules (MTs) and the midzone, and detachment from the mitotic spindle. We found that phosphorylation of S277 is essential for the translocation of Cin8 from SPBs to spindle MTs and the subsequent detachment from the spindle. Phosphorylation of T285 mainly affects the detachment of Cin8 from spindle MTs during anaphase, while phosphorylation at S493 affects both the translocation of Cin8 from SPBs to the spindle and detachment from the spindle. Only S493 phosphorylation affected the anaphase spindle elongation rate. We conclude that each phosphorylation site plays a unique role in regulating Cin8 functions and postulate a model in which the timing and extent of phosphorylation of the three sites orchestrates the anaphase function of Cin8.
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Affiliation(s)
- Alina Goldstein
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, 84105, Beer-Sheva, Israel
| | - Nurit Siegler
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, 84105, Beer-Sheva, Israel
| | - Darya Goldman
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, 84105, Beer-Sheva, Israel
| | - Haim Judah
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, 84105, Beer-Sheva, Israel
| | - Ervin Valk
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Mardo Kõivomägi
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Mart Loog
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Larisa Gheber
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, 84105, Beer-Sheva, Israel.
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26
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Zhu Y, An X, Tomaszewski A, Hepler PK, Lee WL. Microtubule cross-linking activity of She1 ensures spindle stability for spindle positioning. J Cell Biol 2017; 216:2759-2775. [PMID: 28794129 PMCID: PMC5584168 DOI: 10.1083/jcb.201701094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/24/2017] [Accepted: 06/02/2017] [Indexed: 12/19/2022] Open
Abstract
Dynein orients the spindle by pulling on astral microtubules from the cortex. In Saccharomyces cerevisiae, the microtubule-associated protein She1 specifically inhibits dynein in the mother compartment to promote spindle movements toward the bud. Zhu et al. demonstrate that She1 also stabilizes interpolar microtubules, ensuring spindle integrity during dynein-mediated spindle positioning. Dynein mediates spindle positioning in budding yeast by pulling on astral microtubules (MTs) from the cell cortex. The MT-associated protein She1 regulates dynein activity along astral MTs and directs spindle movements toward the bud cell. In addition to localizing to astral MTs, She1 also targets to the spindle, but its role on the spindle remains unknown. Using function-separating alleles, live-cell spindle assays, and in vitro biochemical analyses, we show that She1 is required for the maintenance of metaphase spindle stability. She1 binds and cross-links MTs via a C-terminal MT-binding site. She1 can also self-assemble into ring-shaped oligomers. In cells, She1 stabilizes interpolar MTs, preventing spindle deformations during movement, and we show that this activity is regulated by Ipl1/Aurora B phosphorylation during cell cycle progression. Our data reveal how She1 ensures spindle integrity during spindle movement across the bud neck and suggest a potential link between regulation of spindle integrity and dynein pathway activity.
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Affiliation(s)
- Yili Zhu
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA.,Biology Department, University of Massachusetts, Amherst, MA
| | - Xiaojing An
- Biology Department, University of Massachusetts, Amherst, MA
| | | | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA
| | - Wei-Lih Lee
- Biology Department, University of Massachusetts, Amherst, MA
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27
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Caydasi AK, Khmelinskii A, Duenas-Sanchez R, Kurtulmus B, Knop M, Pereira G. Temporal and compartment-specific signals coordinate mitotic exit with spindle position. Nat Commun 2017; 8:14129. [PMID: 28117323 PMCID: PMC5286211 DOI: 10.1038/ncomms14129] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 12/02/2016] [Indexed: 02/06/2023] Open
Abstract
The spatiotemporal control of mitotic exit is crucial for faithful chromosome segregation during mitosis. In budding yeast, the mitotic exit network (MEN) drives cells out of mitosis, whereas the spindle position checkpoint (SPOC) blocks MEN activity when the anaphase spindle is mispositioned. How the SPOC operates at a molecular level remains unclear. Here, we report novel insights into how mitotic signalling pathways orchestrate chromosome segregation in time and space. We establish that the key function of the central SPOC kinase, Kin4, is to counterbalance MEN activation by the cdc fourteen early anaphase release (FEAR) network in the mother cell compartment. Remarkably, Kin4 becomes dispensable for SPOC function in the absence of FEAR. Cells lacking both FEAR and Kin4 show that FEAR contributes to mitotic exit through regulation of the SPOC component Bfa1 and the MEN kinase Cdc15. Furthermore, we uncover controls that specifically promote mitotic exit in the daughter cell compartment. The mitotic exit network (MEN) triggers mitotic exit and can be blocked by the spindle position checkpoint (SPOC). Here the authors show that SPOC kinase Kin4 counterbalances MEN activation by the Cdc fourteen early anaphase release (FEAR) network in the mother cell and that in the absence of FEAR mitotic exit requires daughter cell-confined factors.
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Affiliation(s)
- Ayse Koca Caydasi
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Anton Khmelinskii
- DKFZ-ZMBH Alliance, Centre for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Rafael Duenas-Sanchez
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Bahtiyar Kurtulmus
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Michael Knop
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,DKFZ-ZMBH Alliance, Centre for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Gislene Pereira
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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28
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Asymmetric Localization of Components and Regulators of the Mitotic Exit Network at Spindle Pole Bodies. Methods Mol Biol 2017; 1505:183-193. [PMID: 27826865 DOI: 10.1007/978-1-4939-6502-1_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Most proteins of the Mitotic Exit Network (MEN) and their upstream regulators localize at spindle pole bodies (SPBs) at least in some stages of the cell cycle. Studying the SPB localization of MEN factors has been extremely useful to elucidate their biological roles, organize them in a hierarchical pathway, and define their dynamics under different conditions.Recruitment to SPBs of the small GTPase Tem1 and the downstream kinases Cdc15 and Mob1/Dbf2 is thought to be essential for Cdc14 activation and mitotic exit, while that of the upstream Tem1 regulators (the Kin4 kinase and the GTPase activating protein Bub2-Bfa1) is important for MEN inhibition upon spindle mispositioning. Here, we describe the detailed fluorescence microscopy procedures that we use in our lab to analyze the localization at SPBs of Mitotic Exit Network (MEN) components tagged with GFP or HA epitopes.
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29
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Scholey JM, Civelekoglu-Scholey G, Brust-Mascher I. Anaphase B. BIOLOGY 2016; 5:biology5040051. [PMID: 27941648 PMCID: PMC5192431 DOI: 10.3390/biology5040051] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 11/16/2022]
Abstract
Anaphase B spindle elongation is characterized by the sliding apart of overlapping antiparallel interpolar (ip) microtubules (MTs) as the two opposite spindle poles separate, pulling along disjoined sister chromatids, thereby contributing to chromosome segregation and the propagation of all cellular life. The major biochemical “modules” that cooperate to mediate pole–pole separation include: (i) midzone pushing or (ii) braking by MT crosslinkers, such as kinesin-5 motors, which facilitate or restrict the outward sliding of antiparallel interpolar MTs (ipMTs); (iii) cortical pulling by disassembling astral MTs (aMTs) and/or dynein motors that pull aMTs outwards; (iv) ipMT plus end dynamics, notably net polymerization; and (v) ipMT minus end depolymerization manifest as poleward flux. The differential combination of these modules in different cell types produces diversity in the anaphase B mechanism. Combinations of antagonist modules can create a force balance that maintains the dynamic pre-anaphase B spindle at constant length. Tipping such a force balance at anaphase B onset can initiate and control the rate of spindle elongation. The activities of the basic motor filament components of the anaphase B machinery are controlled by a network of non-motor MT-associated proteins (MAPs), for example the key MT cross-linker, Ase1p/PRC1, and various cell-cycle kinases, phosphatases, and proteases. This review focuses on the molecular mechanisms of anaphase B spindle elongation in eukaryotic cells and briefly mentions bacterial DNA segregation systems that operate by spindle elongation.
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Affiliation(s)
- Jonathan M Scholey
- Department of Molecular and Cell Biology, University of California, Davis, CA 95616, USA.
| | | | - Ingrid Brust-Mascher
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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30
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Fraschini R. Factors that Control Mitotic Spindle Dynamics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 925:89-101. [PMID: 27722958 DOI: 10.1007/5584_2016_74] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mitosis is the last phase of the cell cycle and it leads to the formation of two daughter cells with the same genetic information. This process must occurr in a very precise way and this task is essential to preserve genetic stability and to maintain cell viability. Accurate chromosome segregation during mitosis is brought about by an important cellular organelle: the mitotic spindle. This structure is made of microtubules, polymers of alpha and beta tubulin, and it is highly dynamic during the cell cycle: it emanates from two microtubules organizing centers (Spindle Pole Bodies, SPBs, in yeast) that are essential to build a short bipolar spindle, and it undergoes two steps of elongation during anaphase A and anaphase B in order to separate sister chromatids. Several proteins are involved in the control of mitotic spindle dynamics and their activity is tightly coordinated with other cell cycle events and with cell cycle progression.
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Affiliation(s)
- Roberta Fraschini
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
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31
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Qi Y, Fan P, Hao Y, Han B, Fang Y, Feng M, Cui Z, Li J. Phosphoproteomic Analysis of Protein Phosphorylation Networks in the Hypopharyngeal Gland of Honeybee Workers (Apis mellifera ligustica). J Proteome Res 2015; 14:4647-61. [DOI: 10.1021/acs.jproteome.5b00530] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Yuping Qi
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
| | - Pei Fan
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
- College
of Bioengineering, Henan University of Technology, No. 100 of Science Road, Zhengzhou 450001, China
| | - Yue Hao
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
| | - Bin Han
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
| | - Yu Fang
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
| | - Mao Feng
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
| | - Ziyou Cui
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
- Department
of Pediatrics, Medical School, and Lillehei Heart Institute, University of Minnesota, Twin Cities 4-240 CCRB, 2231 Sixth Street SE, Minneapolis, Minnesota 55455, United States
| | - Jianke Li
- Institute
of Apicultural Research, Chinese Academy of Agricultural Science, No. 1 Beigou Xiangshan, Beijing 100093, China
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32
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Markus SM, Omer S, Baranowski K, Lee WL. Improved Plasmids for Fluorescent Protein Tagging of Microtubules in Saccharomyces cerevisiae. Traffic 2015; 16:773-786. [PMID: 25711127 PMCID: PMC4795465 DOI: 10.1111/tra.12276] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/23/2015] [Accepted: 02/22/2015] [Indexed: 01/13/2023]
Abstract
The ability to fluorescently label microtubules in live cells has enabled numerous studies of motile and mitotic processes. Such studies are particularly useful in budding yeast owing to the ease with which they can be genetically manipulated and imaged by live cell fluorescence microscopy. Because of problems associated with fusing genes encoding fluorescent proteins (FPs) to the native α-tubulin (TUB1) gene, the FP-Tub1 fusion is generally integrated into the genome such that the endogenous TUB1 locus is left intact. Although such modifications have no apparent consequences on cell viability, it is unknown if these genome-integrated FP-tubulin fusions negatively affect microtubule functions. Thus, a simple, economical and highly sensitive assay of microtubule function is required. Furthermore, the current plasmids available for generation of FP-Tub1 fusions have not kept pace with the development of improved FPs. Here, we have developed a simple and sensitive assay of microtubule function that is sufficient to identify microtubule defects that were not apparent by fluorescence microscopy or cell growth assays. Using results obtained from this assay, we have engineered a new family of 30 FP-Tub1 plasmids that use various improved FPs and numerous selectable markers that upon genome integration have no apparent defect on microtubule function.
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Affiliation(s)
| | | | - Kaitlyn Baranowski
- Biology Department, University of Massachusetts Amherst, 221 Morrill South, 611 North Pleasant Street, Amherst, MA 01003
| | - Wei-Lih Lee
- Biology Department, University of Massachusetts Amherst, 221 Morrill South, 611 North Pleasant Street, Amherst, MA 01003
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33
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Yellman CM, Roeder GS. Cdc14 Early Anaphase Release, FEAR, Is Limited to the Nucleus and Dispensable for Efficient Mitotic Exit. PLoS One 2015; 10:e0128604. [PMID: 26090959 PMCID: PMC4474866 DOI: 10.1371/journal.pone.0128604] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 04/28/2015] [Indexed: 11/21/2022] Open
Abstract
Cdc14 phosphatase is a key regulator of exit from mitosis, acting primarily through antagonism of cyclin-dependent kinase, and is also thought to be important for meiosis. Cdc14 is released from its sequestration site in the nucleolus in two stages, first by the non-essential Cdc Fourteen Early Anaphase Release (FEAR) pathway and later by the essential Mitotic Exit Network (MEN), which drives efficient export of Cdc14 to the cytoplasm. We find that Cdc14 is confined to the nucleus during early mitotic anaphase release, and during its meiosis I release. Proteins whose degradation is directed by Cdc14 as a requirement for mitotic exit (e.g. the B-type cyclin, Clb2), remain stable during mitotic FEAR, a result consistent with Cdc14 being restricted to the nucleus and not participating directly in mitotic exit. Cdc14 released by the FEAR pathway has been proposed to have a wide variety of activities, all of which are thought to promote passage through anaphase. Proposed functions of FEAR include stabilization of anaphase spindles, resolution of the rDNA to allow its segregation, and priming of the MEN so that mitotic exit can occur promptly and efficiently. We tested the model for FEAR functions using the FEAR-deficient mutation net1-6cdk. Our cytological observations indicate that, contrary to the current model, FEAR is fully dispensable for timely progression through a series of anaphase landmarks and mitotic exit, although it is required for timely rDNA segregation. The net1-6cdk mutation suppresses temperature-sensitive mutations in MEN genes, suggesting that rather than activating mitotic exit, FEAR either inhibits the MEN or has no direct effect upon it. One interpretation of this result is that FEAR delays MEN activation to ensure that rDNA segregation occurs before mitotic exit. Our findings clarify the distinction between FEAR and MEN-dependent Cdc14 activities and will help guide emerging quantitative models of this cell cycle transition.
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Affiliation(s)
- Christopher M. Yellman
- Howard Hughes Medical Institute, Chevy Chase, Maryland, 20815, United States of America
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, 06520, United States of America
- * E-mail:
| | - G. Shirleen Roeder
- Howard Hughes Medical Institute, Chevy Chase, Maryland, 20815, United States of America
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, 06520, United States of America
- Department of Genetics, Yale University, New Haven, Connecticut, 06520, United States of America
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34
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Smith K, Griffin B, Byrd H, MacKintosh FC, Kilfoil ML. Nonthermal fluctuations of the mitotic spindle. SOFT MATTER 2015; 11:4396-4401. [PMID: 25927485 DOI: 10.1039/c5sm00149h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present direct measurements of fluctuations in the nucleus of yeast cells. While prior work has shown these fluctuations to be active and non-thermal in character, their origin and time dependence are not understood. We show that the nuclear fluctuations we observe are quantitatively consistent with uncorrelated, active force fluctuations driving a nuclear medium that is dominated by an uncondensed DNA solution, for which we perform rheological measurements on an in vitro model system under similar conditions to what is expected in the nucleus.
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Affiliation(s)
- Kevin Smith
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA.
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35
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Nahaboo W, Zouak M, Askjaer P, Delattre M. Chromatids segregate without centrosomes during Caenorhabditis elegans mitosis in a Ran- and CLASP-dependent manner. Mol Biol Cell 2015; 26:2020-9. [PMID: 25833711 PMCID: PMC4472013 DOI: 10.1091/mbc.e14-12-1577] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/20/2015] [Indexed: 01/23/2023] Open
Abstract
Laser ablation of centrosomes in one-cell Caenorhabditis elegans embryos shows that chromatids can segregate independently of centrosomes and also independently of the activity of kinetochore microtubules during mitosis. CLASP and RanGTP are required to generate this centrosome-independent force, whereas SPD-1 and BMK-1 act as brakes to oppose it. During mitosis, chromosomes are connected to a microtubule-based spindle. Current models propose that displacement of the spindle poles and/or the activity of kinetochore microtubules generate mechanical forces that segregate sister chromatids. Using laser destruction of the centrosomes during Caenorhabditis elegans mitosis, we show that neither of these mechanisms is necessary to achieve proper chromatid segregation. Our results strongly suggest that an outward force generated by the spindle midzone, independently of centrosomes, is sufficient to segregate chromosomes in mitotic cells. Using mutant and RNAi analysis, we show that the microtubule-bundling protein SPD-1/MAP-65 and BMK-1/kinesin-5 act as a brake opposing the force generated by the spindle midzone. Conversely, we identify a novel role for two microtubule-growth and nucleation agents, Ran and CLASP, in the establishment of the centrosome-independent force during anaphase. Their involvement raises the interesting possibility that microtubule polymerization of midzone microtubules is continuously required to sustain chromosome segregation during mitosis.
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Affiliation(s)
- Wallis Nahaboo
- Laboratory of Molecular Biology of the Cell, University of Lyon 1, CNRS UMR5239, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
| | - Melissa Zouak
- Laboratory of Molecular Biology of the Cell, University of Lyon 1, CNRS UMR5239, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
| | - Peter Askjaer
- Andalusian Centre for Developmental Biology, CSIC-Junta de Andalucia, Universidad Pablo de Olavide, Carretera de Utrera, 41012 Seville, Spain
| | - Marie Delattre
- Laboratory of Molecular Biology of the Cell, University of Lyon 1, CNRS UMR5239, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
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36
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Roccuzzo M, Visintin C, Tili F, Visintin R. FEAR-mediated activation of Cdc14 is the limiting step for spindle elongation and anaphase progression. Nat Cell Biol 2015; 17:251-61. [PMID: 25706236 DOI: 10.1038/ncb3105] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/09/2015] [Indexed: 01/01/2023]
Abstract
Cleavage of cohesins and cyclin-dependent kinase (CDK) inhibition are thought to be sufficient for triggering chromosome segregation. Here we identify an essential requirement for anaphase chromosome movement. We show that, at anaphase onset, the phosphatase Cdc14 and the polo-like kinase Cdc5 are redundantly required to drive spindle elongation. This role of Cdc14 is mediated by the FEAR network, a group of proteins that activates Cdc14 at anaphase onset, and we suggest that Cdc5 facilitates both Cdc14 activation and CDK inhibition. We further identify the kinesin-5 motor protein Cin8 as a key target of Cdc14. Indeed, Cin8 mutants lacking critical CDK phosphorylation sites suppress the requirement for Cdc14 and Cdc5 in anaphase spindle elongation. Our results indicate that cohesin dissolution and CDK inhibition per se are not sufficient to drive sister chromatid segregation but that the motor protein Cin8 must be activated to elongate the spindle.
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Affiliation(s)
- Michela Roccuzzo
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
| | - Clara Visintin
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
| | - Federico Tili
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
| | - Rosella Visintin
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
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37
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Wang H, Brust-Mascher I, Scholey JM. The microtubule cross-linker Feo controls the midzone stability, motor composition, and elongation of the anaphase B spindle in Drosophila embryos. Mol Biol Cell 2015; 26:1452-62. [PMID: 25694445 PMCID: PMC4395126 DOI: 10.1091/mbc.e14-12-1631] [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: 12/19/2014] [Accepted: 02/13/2015] [Indexed: 01/19/2023] Open
Abstract
The antiparallel MT-MT cross-linking nonmotor MAP, Feo, controls the organization, stability, and motor composition of the Drosophila embryo anaphase B spindle midzone, thereby facilitating the kinesin-5-driven sliding filament mechanism underlying proper anaphase B spindle elongation and chromosome segregation. Chromosome segregation during anaphase depends on chromosome-to-pole motility and pole-to-pole separation. We propose that in Drosophila embryos, the latter process (anaphase B) depends on a persistent kinesin-5–generated interpolar (ip) microtubule (MT) sliding filament mechanism that “engages” to push apart the spindle poles when poleward flux is turned off. Here we investigated the contribution of the midzonal, antiparallel MT-cross-linking nonmotor MAP, Feo, to this “slide-and-flux-or-elongate” mechanism. Whereas Feo homologues in other systems enhance the midzone localization of the MT-MT cross-linking motors kinesin-4, -5 and -6, the midzone localization of these motors is respectively enhanced, reduced, and unaffected by Feo. Strikingly, kinesin-5 localizes all along ipMTs of the anaphase B spindle in the presence of Feo, including at the midzone, but the antibody-induced dissociation of Feo increases kinesin-5 association with the midzone, which becomes abnormally narrow, leading to impaired anaphase B and incomplete chromosome segregation. Thus, although Feo and kinesin-5 both preferentially cross-link MTs into antiparallel polarity patterns, kinesin-5 cannot substitute for loss of Feo function. We propose that Feo controls the organization, stability, and motor composition of antiparallel ipMTs at the midzone, thereby facilitating the kinesin-5–driven sliding filament mechanism underlying proper anaphase B spindle elongation and chromosome segregation.
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Affiliation(s)
- Haifeng Wang
- Department of Molecular and Cell Biology, University of California at Davis, Davis, CA 95616
| | - Ingrid Brust-Mascher
- Department of Molecular and Cell Biology, University of California at Davis, Davis, CA 95616
| | - Jonathan M Scholey
- Department of Molecular and Cell Biology, University of California at Davis, Davis, CA 95616
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38
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Godfrey M, Kuilman T, Uhlmann F. Nur1 dephosphorylation confers positive feedback to mitotic exit phosphatase activation in budding yeast. PLoS Genet 2015; 11:e1004907. [PMID: 25569132 PMCID: PMC4287440 DOI: 10.1371/journal.pgen.1004907] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 11/20/2014] [Indexed: 12/16/2022] Open
Abstract
Substrate dephosphorylation by the cyclin-dependent kinase (Cdk)-opposing phosphatase, Cdc14, is vital for many events during budding yeast mitotic exit. Cdc14 is sequestered in the nucleolus through inhibitory binding to Net1, from which it is released in anaphase following Net1 phosphorylation. Initial Net1 phosphorylation depends on Cdk itself, in conjunction with proteins of the Cdc14 Early Anaphase Release (FEAR) network. Later on, the Mitotic Exit Network (MEN) signaling cascade maintains Cdc14 release. An important unresolved question is how Cdc14 activity can increase in early anaphase, while Cdk activity, that is required for Net1 phosphorylation, decreases and the MEN is not yet active. Here we show that the nuclear rim protein Nur1 interacts with Net1 and, in its Cdk phosphorylated form, inhibits Cdc14 release. Nur1 is dephosphorylated by Cdc14 in early anaphase, relieving the inhibition and promoting further Cdc14 release. Nur1 dephosphorylation thus describes a positive feedback loop in Cdc14 phosphatase activation during mitotic exit, required for faithful chromosome segregation and completion of the cell division cycle. During the cell cycle, a specific sequence of events leads to the formation of two daughter cells from one mother cell. Progression through the cell cycle is tightly controlled, with events occurring in the right place at the right time. Exactly how this is achieved is still being elucidated. In budding yeast, the events occurring during the final cell cycle phase – “mitotic exit” – are controlled by the phosphatase Cdc14. It is kept sequestered and inactive until it is needed for mitotic exit, at which time it is rapidly released. In this study, we have identified a new regulator of Cdc14 activity, the protein Nur1. In a series of experiments, we saw that Nur1 acts both upstream and downstream of Cdc14 activation, thereby creating a positive feedback loop. On the one hand, Nur1 contributes to inhibiting Cdc14 until the start of mitotic exit. On the other hand, through the actions of Cdc14 itself, Nur1 is disabled as an opponent of the phosphatase. This creates a robust system, rapidly switching between two opposing states and thus driving forward the mitotic exit transition.
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Affiliation(s)
- Molly Godfrey
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London, United Kingdom
| | - Thomas Kuilman
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London, United Kingdom
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London, United Kingdom
- * E-mail:
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39
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Ward JJ, Roque H, Antony C, Nédélec F. Mechanical design principles of a mitotic spindle. eLife 2014; 3:e03398. [PMID: 25521247 PMCID: PMC4290452 DOI: 10.7554/elife.03398] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 12/17/2014] [Indexed: 12/11/2022] Open
Abstract
An organised spindle is crucial to the fidelity of chromosome segregation, but the relationship between spindle structure and function is not well understood in any cell type. The anaphase B spindle in fission yeast has a slender morphology and must elongate against compressive forces. This 'pushing' mode of chromosome transport renders the spindle susceptible to breakage, as observed in cells with a variety of defects. Here we perform electron tomographic analyses of the spindle, which suggest that it organises a limited supply of structural components to increase its compressive strength. Structural integrity is maintained throughout the spindle's fourfold elongation by organising microtubules into a rigid transverse array, preserving correct microtubule number and dynamically rescaling microtubule length.
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Affiliation(s)
- Jonathan J Ward
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Hélio Roque
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Claude Antony
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - François Nédélec
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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40
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Thiede C, Fridman V, Gerson-Gurwitz A, Gheber L, Schmidt CF. Regulation of bi-directional movement of single kinesin-5 Cin8 molecules. BIOARCHITECTURE 2014; 2:70-74. [PMID: 22754632 PMCID: PMC3383724 DOI: 10.4161/bioa.20395] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Kinesin-5 mechanoenzymes drive mitotic spindle dynamics as slow, processive microtubule (MT)-plus-end directed motors. Surprisingly, the Saccharomyces cerevisiae kinesin-5 Cin8 was recently found to be bi-directional: it can move processively in both directions on MTs. Two hypotheses have been suggested for the mechanism of the directionality switch: (1) single molecules of Cin8 are intrinsically minus-end directed, but mechanical coupling between two or more motors triggers the switch; (2) a single motor can switch direction, and "cargo binding" i.e., binding between two MTs triggers the switch to plus-end motility. Single-molecule fluorescence data we published recently, and augment here, favor hypothesis (2). In low-ionic-strength conditions, single molecules of Cin8 move in both minus- and plus-end directions. Fluorescence photo bleaching data rule out aggregation of Cin8 while they move in the plus and in the minus direction. The evidence thus points toward cargo regulation of directionality, which is likely to be related to cargo regulation in other kinesins. The molecular mechanisms of this regulation, however, remain to be elucidated.
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41
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Surana U, Liang H, Lim HH. Staging a recovery from mitotic arrest: Unusual ways of Cdk1. BIOARCHITECTURE 2014; 2:33-37. [PMID: 22754627 PMCID: PMC3383719 DOI: 10.4161/bioa.20421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Checkpoint controls, the surveillance pathways that impose "an order of execution" on the major cell cycle events, are critical to the maintenance of genome stability. When cells fail to execute a cellular event or do so erroneously due to misregulation or exposure to genotoxic stresses, these evolutionarily conserved regulatory circuits prevent passage to the subsequent event, thus bringing the cell cycle to a halt. Once the checkpoint stimulus is removed, cells recover from the arrest and eventually resume cell cycle progression. While the activation, execution and maintenance, the three major aspects of the checkpoint controls, have been investigated in detail, the recovery process remains underexplored. It is not clear if cells recover passively upon dissipation of the checkpoint signals or require an active participation by specific effectors. A recent study in the yeast Saccharomyces cerevisiae uncovered two previously unsuspected functions of Cdk1 in efficient recovery from the spindle assembly checkpoint (SAC) imposed arrest. An inability to fulfil these requirements in the absence of Cdk1 makes it virtually impossible for cells to recover from the mitotic arrest. Given the conserved nature of the SAC, these findings may have implications for vertebrate cells.
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Affiliation(s)
- Uttam Surana
- Institute of Molecular and Cell Biology; Proteos, Singapore
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42
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Lu D, Hsiao JY, Davey NE, Van Voorhis VA, Foster SA, Tang C, Morgan DO. Multiple mechanisms determine the order of APC/C substrate degradation in mitosis. ACTA ACUST UNITED AC 2014; 207:23-39. [PMID: 25287299 PMCID: PMC4195823 DOI: 10.1083/jcb.201402041] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
To ensure proper mitotic progression, robust ordering of the destruction of APC/CCdc20 substrates is driven by the integration of molecular mechanisms ranging from phosphorylation-dependent interaction with substrates to sensing of the status of the spindle assembly checkpoint. The ubiquitin protein ligase anaphase-promoting complex or cyclosome (APC/C) controls mitosis by promoting ordered degradation of securin, cyclins, and other proteins. The mechanisms underlying the timing of APC/C substrate degradation are poorly understood. We explored these mechanisms using quantitative fluorescence microscopy of GFP-tagged APC/CCdc20 substrates in living budding yeast cells. Degradation of the S cyclin, Clb5, begins early in mitosis, followed 6 min later by the degradation of securin and Dbf4. Anaphase begins when less than half of securin is degraded. The spindle assembly checkpoint delays the onset of Clb5 degradation but does not influence securin degradation. Early Clb5 degradation depends on its interaction with the Cdk1–Cks1 complex and the presence of a Cdc20-binding “ABBA motif” in its N-terminal region. The degradation of securin and Dbf4 is delayed by Cdk1-dependent phosphorylation near their Cdc20-binding sites. Thus, a remarkably diverse array of mechanisms generates robust ordering of APC/CCdc20 substrate destruction.
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Affiliation(s)
- Dan Lu
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Jennifer Y Hsiao
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Norman E Davey
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Vanessa A Van Voorhis
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Scott A Foster
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Chao Tang
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - David O Morgan
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
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43
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Landry CR, Freschi L, Zarin T, Moses AM. Turnover of protein phosphorylation evolving under stabilizing selection. Front Genet 2014; 5:245. [PMID: 25101120 PMCID: PMC4107968 DOI: 10.3389/fgene.2014.00245] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/08/2014] [Indexed: 12/31/2022] Open
Abstract
Most proteins are regulated by posttranslational modifications and changes in these modifications contribute to evolutionary changes as well as to human diseases. Phosphorylation of serines, threonines, and tyrosines are the most common modifications identified to date in eukaryotic proteomes. While the mode of action and the function of most phosphorylation sites remain unknown, functional studies have shown that phosphorylation affects protein stability, localization and ability to interact. Two broad modes of action have been described for protein phosphorylation. The first mode corresponds to the canonical and qualitative view whereby single phosphorylation sites act as molecular switches that either turn on or off specific protein functions through direct or allosteric effects. The second mode is more akin to a rheostat than a switch. In this case, a group of phosphorylation sites in a given protein region contributes collectively to the modification of the protein, irrespective of the precise position of individual sites, through an aggregate property. Here we discuss these two types of regulation and examine how they affect the rate and patterns of protein phosphorylation evolution. We describe how the evolution of clusters of phosphorylation sites can be studied under the framework of complex traits evolution and stabilizing selection.
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Affiliation(s)
- Christian R Landry
- Département de Biologie, Université Laval Québec, QC, Canada ; Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval Québec, QC, Canada ; Network for Research on Protein Function, Structure, and Engineering (PROTEO), Univeristé Laval Québec, QC, Canada
| | - Luca Freschi
- Département de Biologie, Université Laval Québec, QC, Canada ; Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval Québec, QC, Canada ; Network for Research on Protein Function, Structure, and Engineering (PROTEO), Univeristé Laval Québec, QC, Canada
| | - Taraneh Zarin
- Department of Cell and Systems Biology, University of Toronto Toronto, ON, Canada
| | - Alan M Moses
- Department of Cell and Systems Biology, University of Toronto Toronto, ON, Canada ; Department of Ecology and Evolutionary Biology, University of Toronto Toronto, ON, Canada ; Center for Analysis of Genome Evolution and Function, University of Toronto Toronto, ON, Canada
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Aiken J, Sept D, Costanzo M, Boone C, Cooper JA, Moore JK. Genome-wide analysis reveals novel and discrete functions for tubulin carboxy-terminal tails. Curr Biol 2014; 24:1295-1303. [PMID: 24835459 DOI: 10.1016/j.cub.2014.03.078] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/27/2014] [Accepted: 03/31/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND Microtubules (MTs) support diverse transport and force generation processes in cells. Both α- and β-tubulin proteins possess carboxy-terminal tail regions (CTTs) that are negatively charged, intrinsically disordered, and project from the MT surface where they interact with motors and other proteins. Although CTTs are presumed to play important roles in MT networks, these roles have not been determined in vivo. RESULTS We examined the function of CTTs in vivo by using a systematic collection of mutants in budding yeast. We find that CTTs are not essential; however, loss of either α- or β-CTT sensitizes cells to MT-destabilizing drugs. β-CTT, but not α-CTT, regulates MT dynamics by increasing frequencies of catastrophe and rescue events. In addition, β-CTT is critical for the assembly of the mitotic spindle and its elongation during anaphase. We use genome-wide genetic interaction screens to identify roles for α- and β-CTTs, including a specific role for β-CTT in supporting kinesin-5/Cin8. Our genetic screens also identified novel interactions with pathways not related to canonical MT functions. CONCLUSIONS We conclude that α- and β-CTTs play important and largely discrete roles in MT networks. β-CTT promotes MT dynamics. β-CTT also regulates force generation in the mitotic spindle by supporting kinesin-5/Cin8 and dampening dynein. Our genetic screens identify links between α- and β-CTT and additional cellular pathways and suggest novel functions.
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Affiliation(s)
- Jayne Aiken
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - David Sept
- Department of Biomedical Engineering and Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michael Costanzo
- Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Charles Boone
- Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - John A Cooper
- Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63110, USA
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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McKnight K, Liu H, Wang Y. Replicative stress induces intragenic transcription of the ASE1 gene that negatively regulates Ase1 activity. Curr Biol 2014; 24:1101-6. [PMID: 24768052 DOI: 10.1016/j.cub.2014.03.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 02/14/2014] [Accepted: 03/14/2014] [Indexed: 02/01/2023]
Abstract
Intragenic transcripts initiate within the coding region of a gene, thereby producing shorter mRNAs and proteins. Although intragenic transcripts are widely expressed [1], their role in the functional regulation of genes remains largely unknown. In budding yeast, DNA replication stress activates the S phase checkpoint that stabilizes replication forks and arrests cells in S phase with a short spindle [2-4]. When yeast cells were treated with hydroxyurea (HU) to block DNA synthesis and induce replication stress, we found that Ase1, a conserved spindle midzone protein [5], appeared as two short protein isoforms in addition to the full-length protein. We further demonstrated that the short isoforms result from intragenic transcription of ASE1, which depends on the S phase checkpoint. Blocking generation of the short isoforms leads to a destabilized S phase spindle, characterized by increased spindle dynamics and frequent spindle collapse. Because the short Ase1 isoforms localize at the spindle in HU-treated cells and overexpression of the short Ase1 isoforms impairs the spindle midzone localization of full-length Ase1, it is likely that the presence of short Ase1 isoforms stabilizes the spindle by antagonizing full-length Ase1. Together, our results reveal intragenic transcription as a unique mechanism to downregulate gene functions in response to DNA replication stress.
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Affiliation(s)
- Kelly McKnight
- Department of Biomedical Sciences, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL 32306, USA
| | - Hong Liu
- Department of Biomedical Sciences, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL 32306, USA
| | - Yanchang Wang
- Department of Biomedical Sciences, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL 32306, USA.
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Cassani C, Raspelli E, Chiroli E, Fraschini R. Vhs2 is a novel regulator of septin dynamics in budding yeast. Cell Cycle 2014; 13:1590-601. [PMID: 24646733 DOI: 10.4161/cc.28561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In budding yeast, septins are assembled into structures that undergo dramatic changes during the cell cycle. The molecular mechanisms that drive these remodelings are not fully uncovered. In this study, we describe a characterization of Vhs2, a nonessential protein that revealed to be a new player in septin dynamics. In particular, we report that Vhs2 is important to maintain the stability of the double septin ring structure until telophase. In addition, we show that Vhs2 undergoes multiple phosphorylations during the cell cycle, being phosphorylated during S phase until nuclear division and dephosphorylated just before cell division. Importantly we report that cyclin-dependent protein kinase Cdk1 and protein phosphatase Cdc14 control these Vhs2 post-translational modifications. These results reveal that Vhs2 is a novel Cdc14 substrate that is involved in the control of septin organization.
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Affiliation(s)
- Corinne Cassani
- Università degli Studi di Milano-Bicocca; Dipartimento di Biotecnologie e Bioscienze; Milano, Italy
| | - Erica Raspelli
- Università degli Studi di Milano-Bicocca; Dipartimento di Biotecnologie e Bioscienze; Milano, Italy
| | - Elena Chiroli
- IFOM - Istituto FIRC di Oncologia Molecolare; Milano, Italy
| | - Roberta Fraschini
- Università degli Studi di Milano-Bicocca; Dipartimento di Biotecnologie e Bioscienze; Milano, Italy
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47
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Rizk RS, Discipio KA, Proudfoot KG, Gupta ML. The kinesin-8 Kip3 scales anaphase spindle length by suppression of midzone microtubule polymerization. ACTA ACUST UNITED AC 2014; 204:965-75. [PMID: 24616221 PMCID: PMC3998799 DOI: 10.1083/jcb.201312039] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mitotic spindle function is critical for cell division and genomic stability. During anaphase, the elongating spindle physically segregates the sister chromatids. However, the molecular mechanisms that determine the extent of anaphase spindle elongation remain largely unclear. In a screen of yeast mutants with altered spindle length, we identified the kinesin-8 Kip3 as essential to scale spindle length with cell size. Kip3 is a multifunctional motor protein with microtubule depolymerase, plus-end motility, and antiparallel sliding activities. Here we demonstrate that the depolymerase activity is indispensable to control spindle length, whereas the motility and sliding activities are not sufficient. Furthermore, the microtubule-destabilizing activity is required to counteract Stu2/XMAP215-mediated microtubule polymerization so that spindle elongation terminates once spindles reach the appropriate final length. Our data support a model where Kip3 directly suppresses spindle microtubule polymerization, limiting midzone length. As a result, sliding forces within the midzone cannot buckle spindle microtubules, which allows the cell boundary to define the extent of spindle elongation.
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Affiliation(s)
- Rania S Rizk
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
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48
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Functional divergence and evolutionary turnover in mammalian phosphoproteomes. PLoS Genet 2014; 10:e1004062. [PMID: 24465218 PMCID: PMC3900387 DOI: 10.1371/journal.pgen.1004062] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 11/11/2013] [Indexed: 11/29/2022] Open
Abstract
Protein phosphorylation is a key mechanism to regulate protein functions. However, the contribution of this protein modification to species divergence is still largely unknown. Here, we studied the evolution of mammalian phosphoregulation by comparing the human and mouse phosphoproteomes. We found that 84% of the positions that are phosphorylated in one species or the other are conserved at the residue level. Twenty percent of these conserved sites are phosphorylated in both species. This proportion is 2.5 times more than expected by chance alone, suggesting that purifying selection is preserving phosphoregulation. However, we show that the majority of the sites that are conserved at the residue level are differentially phosphorylated between species. These sites likely result from false-negative identifications due to incomplete experimental coverage, false-positive identifications and non-functional sites. In addition, our results suggest that at least 5% of them are likely to be true differentially phosphorylated sites and may thus contribute to the divergence in phosphorylation networks between mouse and humans and this, despite residue conservation between orthologous proteins. We also showed that evolutionary turnover of phosphosites at adjacent positions (in a distance range of up to 40 amino acids) in human or mouse leads to an over estimation of the divergence in phosphoregulation between these two species. These sites tend to be phosphorylated by the same kinases, supporting the hypothesis that they are functionally redundant. Our results support the hypothesis that the evolutionary turnover of phosphorylation sites contributes to the divergence in phosphorylation profiles while preserving phosphoregulation. Overall, our study provides advanced analyses of mammalian phosphoproteomes and a framework for the study of their contribution to phenotypic evolution. Understanding how differences in cellular regulation lead to phenotypic differences between species remains an open challenge in evolutionary genetics. The extensive phosphorylation data currently available allows to compare the human and mouse phosphoproteomes and to measure changes in their phosphoregulation. We found a general conservation of phosphorylation sites between these two species. However, a fraction of sites are conserved at the sequence level (the same amino acid is present in both species) but differ in their phosphorylation status. These sites represent candidate sites that have the potential to explain differences between human and mouse signalling networks that do not depend on the divergence of orthologous residues. Furthermore, we identified several sites where to a phosphorylation site in one species corresponds a non-phosphorylatable residue in the other one. These cases represent clear differences in protein regulation. Recent studies suggest that phosphorylation sites can shift position during evolution, leading to configurations in which pairs of divergent phosphorylation sites are functionally redundant. We identified more than 100 putative such cases, suggesting that divergence in amino acid does not necessarily imply functional divergence when comparing phosphoproteomes. Overall, our study provides new key concepts and data for the study of how regulatory differences may be linked to phenotypic ones at the network level.
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49
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Naylor SG, Morgan DO. Cdk1-dependent phosphorylation of Iqg1 governs actomyosin ring assembly prior to cytokinesis. J Cell Sci 2014; 127:1128-37. [PMID: 24413167 DOI: 10.1242/jcs.144097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Contraction of the actomyosin ring (AMR) provides the centripetal force that drives cytokinesis. In budding yeast (Saccharomyces cerevisiae), assembly and contraction of the AMR is coordinated with membrane deposition and septum formation at the bud neck. A central player in this process is Iqg1, which promotes recruitment of actin to the myosin ring and links AMR assembly with that of septum-forming components. We observed early actin recruitment in response to inhibition of cyclin-dependent kinase 1 (Cdk1) activity, and we find that the Cdk1-dependent phosphorylation state of Iqg1 is a determining factor in the timing of bud neck localization of both Iqg1 and actin, with both proteins accumulating prematurely in cells expressing nonphosphorylatable Iqg1 mutants. We also identified the primary septum regulator Hof1 as a binding partner of Iqg1, providing a regulatory link between the septation and contractile pathways that cooperate to complete cytokinesis.
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Affiliation(s)
- Stephen G Naylor
- Departments of Physiology and Biochemistry & Biophysics, University of California, San Francisco, CA 94158, USA
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50
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Marston AL. Chromosome segregation in budding yeast: sister chromatid cohesion and related mechanisms. Genetics 2014; 196:31-63. [PMID: 24395824 PMCID: PMC3872193 DOI: 10.1534/genetics.112.145144] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 09/18/2013] [Indexed: 12/28/2022] Open
Abstract
Studies on budding yeast have exposed the highly conserved mechanisms by which duplicated chromosomes are evenly distributed to daughter cells at the metaphase-anaphase transition. The establishment of proteinaceous bridges between sister chromatids, a function provided by a ring-shaped complex known as cohesin, is central to accurate segregation. It is the destruction of this cohesin that triggers the segregation of chromosomes following their proper attachment to microtubules. Since it is irreversible, this process must be tightly controlled and driven to completion. Furthermore, during meiosis, modifications must be put in place to allow the segregation of maternal and paternal chromosomes in the first division for gamete formation. Here, I review the pioneering work from budding yeast that has led to a molecular understanding of the establishment and destruction of cohesion.
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Affiliation(s)
- Adele L Marston
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
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