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Rathi S, Polat I, Pereira G. The budding yeast GSK-3 homologue Mck1 is an essential component of the spindle position checkpoint. Open Biol 2022; 12:220203. [PMID: 36321416 PMCID: PMC9627454 DOI: 10.1098/rsob.220203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The spindle position checkpoint (SPOC) is a mitotic surveillance mechanism in Saccharomyces cerevisiae that prevents cells from completing mitosis in response to spindle misalignment, thereby contributing to genomic integrity. The kinase Kin4, one of the most downstream SPOC components, is essential to stop the mitotic exit network (MEN), a signalling pathway that promotes the exit from mitosis and cell division. Previous work, however, suggested that a Kin4-independent pathway contributes to SPOC, yet the underlying mechanisms remain elusive. Here, we established the glycogen-synthase-kinase-3 (GSK-3) homologue Mck1, as a novel component that works independently of Kin4 to engage SPOC. Our data indicate that both Kin4 and Mck1 work in parallel to counteract MEN activation by the Cdc14 early anaphase release (FEAR) network. We show that Mck1's function in SPOC is mediated by the pre-replication complex protein and mitotic cyclin-dependent kinase (M-Cdk) inhibitor, Cdc6, which is degraded in a Mck1-dependent manner prior to mitosis. Moderate overproduction of Cdc6 phenocopies MCK1 deletion and causes SPOC deficiency via its N-terminal, M-Cdk inhibitory domain. Our data uncover an unprecedented role of GSK-3 kinases in coordinating spindle orientation with cell cycle progression.
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Affiliation(s)
- Siddhi Rathi
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany,Heidelberg Biosciences International Graduate School (HBIGS) and Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany,German Academic Exchange Service (DAAD), Bonn, Germany
| | - Irem Polat
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - Gislene Pereira
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany,Centre for Molecular Biology (ZMBH), University of Heidelberg, Heidelberg, Germany,German Cancer Research Centre (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
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2
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Rathi S, Polat I, Pereira G. The budding yeast GSK-3 homologue Mck1 is an essential component of the spindle position checkpoint. Open Biol 2022. [PMID: 36321416 DOI: 10.6084/m9.figshare.c.6261880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The spindle position checkpoint (SPOC) is a mitotic surveillance mechanism in Saccharomyces cerevisiae that prevents cells from completing mitosis in response to spindle misalignment, thereby contributing to genomic integrity. The kinase Kin4, one of the most downstream SPOC components, is essential to stop the mitotic exit network (MEN), a signalling pathway that promotes the exit from mitosis and cell division. Previous work, however, suggested that a Kin4-independent pathway contributes to SPOC, yet the underlying mechanisms remain elusive. Here, we established the glycogen-synthase-kinase-3 (GSK-3) homologue Mck1, as a novel component that works independently of Kin4 to engage SPOC. Our data indicate that both Kin4 and Mck1 work in parallel to counteract MEN activation by the Cdc14 early anaphase release (FEAR) network. We show that Mck1's function in SPOC is mediated by the pre-replication complex protein and mitotic cyclin-dependent kinase (M-Cdk) inhibitor, Cdc6, which is degraded in a Mck1-dependent manner prior to mitosis. Moderate overproduction of Cdc6 phenocopies MCK1 deletion and causes SPOC deficiency via its N-terminal, M-Cdk inhibitory domain. Our data uncover an unprecedented role of GSK-3 kinases in coordinating spindle orientation with cell cycle progression.
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Affiliation(s)
- Siddhi Rathi
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany.,Heidelberg Biosciences International Graduate School (HBIGS) and Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany.,German Academic Exchange Service (DAAD), Bonn, Germany
| | - Irem Polat
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - Gislene Pereira
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany.,Centre for Molecular Biology (ZMBH), University of Heidelberg, Heidelberg, Germany.,German Cancer Research Centre (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
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3
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Philip J, Örd M, Silva A, Singh S, Diffley JFX, Remus D, Loog M, Ikui AE. Cdc6 is sequentially regulated by PP2A-Cdc55, Cdc14, and Sic1 for origin licensing in S. cerevisiae. eLife 2022; 11:e74437. [PMID: 35142288 PMCID: PMC8830886 DOI: 10.7554/elife.74437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/15/2021] [Indexed: 01/31/2023] Open
Abstract
Cdc6, a subunit of the pre-replicative complex (pre-RC), contains multiple regulatory cyclin-dependent kinase (Cdk1) consensus sites, SP or TP motifs. In Saccharomyces cerevisiae, Cdk1 phosphorylates Cdc6-T7 to recruit Cks1, the Cdk1 phospho-adaptor in S phase, for subsequent multisite phosphorylation and protein degradation. Cdc6 accumulates in mitosis and is tightly bound by Clb2 through N-terminal phosphorylation in order to prevent premature origin licensing and degradation. It has been extensively studied how Cdc6 phosphorylation is regulated by the cyclin-Cdk1 complex. However, a detailed mechanism on how Cdc6 phosphorylation is reversed by phosphatases has not been elucidated. Here, we show that PP2ACdc55 dephosphorylates Cdc6 N-terminal sites to release Clb2. Cdc14 dephosphorylates the C-terminal phospho-degron, leading to Cdc6 stabilization in mitosis. In addition, Cdk1 inhibitor Sic1 releases Clb2·Cdk1·Cks1 from Cdc6 to load Mcm2-7 on the chromatin upon mitotic exit. Thus, pre-RC assembly and origin licensing are promoted by phosphatases through the attenuation of distinct Cdk1-dependent Cdc6 inhibitory mechanisms.
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Affiliation(s)
- Jasmin Philip
- The PhD Program in Biochemistry, The Graduate Center, CUNYBrooklynUnited States
- Brooklyn CollegeBrooklynUnited States
| | | | - Andriele Silva
- The PhD Program in Biochemistry, The Graduate Center, CUNYBrooklynUnited States
- Brooklyn CollegeBrooklynUnited States
| | - Shaneen Singh
- The PhD Program in Biochemistry, The Graduate Center, CUNYBrooklynUnited States
- Brooklyn CollegeBrooklynUnited States
| | | | - Dirk Remus
- Memorial Sloan-Kettering Cancer CenterNew YorkUnited States
| | | | - Amy E Ikui
- The PhD Program in Biochemistry, The Graduate Center, CUNYBrooklynUnited States
- Brooklyn CollegeBrooklynUnited States
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4
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Yi ZY, Meng TG, Ma XS, Li J, Zhang CH, Ouyang YC, Schatten H, Qiao J, Sun QY, Qian WP. CDC6 regulates both G2/M transition and metaphase-to-anaphase transition during the first meiosis of mouse oocytes. J Cell Physiol 2020; 235:5541-5554. [PMID: 31984513 DOI: 10.1002/jcp.29469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 01/06/2020] [Indexed: 12/30/2022]
Abstract
Cell division cycle protein, CDC6, is essential for the initiation of DNA replication. CDC6 was recently shown to inhibit the microtubule-organizing activity of the centrosome. Here, we show that CDC6 is localized to the spindle from pro-metaphase I (MI) to MII stages of oocytes, and it plays important roles at two critical steps of oocyte meiotic maturation. CDC6 depletion facilitated the G2/M transition (germinal vesicle breakdown [GVBD]) through regulation of Cdh1 and cyclin B1 expression and CDK1 (CDC2) phosphorylation in a GVBD-inhibiting culture system containing milrinone. Furthermore, GVBD was significantly decreased after knockdown of cyclin B1 in CDC6-depleted oocytes, indicating that the effect of CDC6 loss on GVBD stimulation was mediated, at least in part, by raising cyclin B1. Knockdown of CDC6 also caused abnormal localization of γ-tubulin, resulting in defective spindles, misaligned chromosomes, cyclin B1 accumulation, and spindle assembly checkpoint (SAC) activation, leading to significant pro-MI/MI arrest and PB1 extrusion failure. These phenotypes were also confirmed by time-lapse live cell imaging analysis. The results indicate that CDC6 is indispensable for maintaining G2 arrest of meiosis and functions in G2/M checkpoint regulation in mouse oocytes. Moreover, CDC6 is also a key player regulating meiotic spindle assembly and metaphase-to-anaphase transition in meiotic oocytes.
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Affiliation(s)
- Zi-Yun Yi
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Tie-Gang Meng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xue-Shan Ma
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Jian Li
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Chun-Hui Zhang
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Ying-Chun Ouyang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri
| | - Jie Qiao
- Reproductive Medical Center, Peking University Third Hospital, Beijing, China
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Wei-Ping Qian
- The Reproductive Medicine Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
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5
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Baro B, Játiva S, Calabria I, Vinaixa J, Bech-Serra JJ, de LaTorre C, Rodrigues J, Hernáez ML, Gil C, Barceló-Batllori S, Larsen MR, Queralt E. SILAC-based phosphoproteomics reveals new PP2A-Cdc55-regulated processes in budding yeast. Gigascience 2018; 7:4982941. [PMID: 29688323 PMCID: PMC5967524 DOI: 10.1093/gigascience/giy047] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 04/18/2018] [Indexed: 01/12/2023] Open
Abstract
Background Protein phosphatase 2A (PP2A) is a family of conserved serine/threonine phosphatases involved in several essential aspects of cell growth and proliferation. PP2ACdc55 phosphatase has been extensively related to cell cycle events in budding yeast; however, few PP2ACdc55 substrates have been identified. Here, we performed a quantitative mass spectrometry approach to reveal new substrates of PP2ACdc55 phosphatase and new PP2A-related processes in mitotic arrested cells. Results We identified 62 statistically significant PP2ACdc55 substrates involved mainly in actin-cytoskeleton organization. In addition, we validated new PP2ACdc55 substrates such as Slk19 and Lte1, involved in early and late anaphase pathways, and Zeo1, a component of the cell wall integrity pathway. Finally, we constructed docking models of Cdc55 and its substrate Mob1. We found that the predominant interface on Cdc55 is mediated by a protruding loop consisting of residues 84–90, thus highlighting the relevance of these aminoacids for substrate interaction. Conclusions We used phosphoproteomics of Cdc55-deficient cells to uncover new PP2ACdc55 substrates and functions in mitosis. As expected, several hyperphosphorylated proteins corresponded to Cdk1-dependent substrates, although other kinases’ consensus motifs were also enriched in our dataset, suggesting that PP2ACdc55 counteracts and regulates other kinases distinct from Cdk1. Indeed, Pkc1 emerged as a novel node of PP2ACdc55 regulation, highlighting a major role of PP2ACdc55 in actin cytoskeleton and cytokinesis, gene ontology terms significantly enriched in the PP2ACdc55-dependent phosphoproteome.
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Affiliation(s)
- Barbara Baro
- Cell Cycle Group, Cancer Epigenetics and Biology Program, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Soraya Játiva
- Cell Cycle Group, Cancer Epigenetics and Biology Program, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Inés Calabria
- Cell Cycle Group, Cancer Epigenetics and Biology Program, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Judith Vinaixa
- Cell Cycle Group, Cancer Epigenetics and Biology Program, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Joan-Josep Bech-Serra
- IDIBELL Proteomics Unit, Institut d'Investigacions Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Carolina de LaTorre
- IDIBELL Proteomics Unit, Institut d'Investigacions Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - João Rodrigues
- Structural Biology Department, School of Medicine, Stanford, California, USA
| | - María Luisa Hernáez
- Proteomics Unit, Parque Científico de Madrid, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Concha Gil
- Proteomics Unit, Parque Científico de Madrid, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Silvia Barceló-Batllori
- IDIBELL Proteomics Unit, Institut d'Investigacions Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, Odense M, Denmark
| | - Ethel Queralt
- Cell Cycle Group, Cancer Epigenetics and Biology Program, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
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6
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Tsugama D, Liu S, Fujino K, Takano T. B-family subunits of protein phosphatase 2A are necessary for pollen development but not for female gametophyte development in Arabidopsis. Biochem Biophys Res Commun 2018; 505:176-180. [PMID: 30243715 DOI: 10.1016/j.bbrc.2018.09.088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 09/13/2018] [Indexed: 11/30/2022]
Abstract
Protein phosphatase 2A (PP2A) is a heterotrimeric protein complex conserved among eukaryotes. The B subunit of PP2A determines the substrate specificity of the PP2A holoenzyme, and is classified into the B, B', B″ and B‴ families. Arabidopsis thaliana has two isoforms of the B-family subunit (ATBA and ATBB). A double knockout of their genes is lethal, but which developmental process is primarily impaired by the double knockout is unclear. Identifying such a process helps understand PP2A-mediated signaling more deeply. Here, genetic characterization of new knockout mutants for these genes shows that they are necessary for pollen development but not for female gametophyte development. Compared to wild-type pollen grains, the mutant pollen grains exhibited lower enzyme activities, germinated less frequently on stigmas, and exhibited the aberrant numbers of sperm cell nuclei, suggesting that ATBA and ATBB play pleiotropic roles in pollen development. The amino acids stabilizing the interaction between the human PP2A A and B-family subunits are conserved in an Arabidopsis A subunit (AtPP2AA2), ATBA and ATBB. His-tagged AtPP2AA2 co-immunoprecipitated with either Myc-tagged ATBA or Myc-tagged ATBB in vitro, confirming their interactions. Proteins that regulate pollen development and that undergo dephosphorylation are likely primary targets of ATBA and ATBB.
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Affiliation(s)
- Daisuke Tsugama
- Laboratory of Crop Physiology, Research Faculty of Agriculture, Hokkaido University Kita 9 Nishi 9 Kita-ku, Sapporo-shi, Hokkaido, 060-8589, Japan; Asian Natural Environmental Science Center, The University of Tokyo 1-1-1 Midori-cho, Nishitokyo-shi, Tokyo, 188-0002, Japan.
| | - Shenkui Liu
- State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Lin'an, Hangzhou, 311300, PR China
| | - Kaien Fujino
- Laboratory of Crop Physiology, Research Faculty of Agriculture, Hokkaido University Kita 9 Nishi 9 Kita-ku, Sapporo-shi, Hokkaido, 060-8589, Japan
| | - Tetsuo Takano
- Asian Natural Environmental Science Center, The University of Tokyo 1-1-1 Midori-cho, Nishitokyo-shi, Tokyo, 188-0002, Japan
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7
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Wu SY, Kuan VJW, Tzeng YW, Schuyler SC, Juang YL. The anaphase-promoting complex works together with the SCF complex for proteolysis of the S-phase cyclin Clb6 during the transition from G1 to S phase. Fungal Genet Biol 2016; 91:6-19. [PMID: 26994663 DOI: 10.1016/j.fgb.2016.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/11/2016] [Accepted: 03/15/2016] [Indexed: 11/18/2022]
Abstract
In Saccharomyces cerevisiae, the S-phase cyclin Clb6 is expressed shortly before the G1/S transition. It has been shown that in S phase the SCF(Cdc4) ubiquitin ligase controls Clb6 proteolysis, which requires cyclin-dependent kinases activity. A Clb6-3A mutant, bearing non-phosphorylatable mutations at S6A, T39A, and S147A, was observed to be hyperstabilized in S-phase but was unstable in mitosis. In this study, we found that the APC(Cdh1) form of the Anaphase-Promoting Complex (APC) was required for Clb6 proteolysis in both early and late G1. An in vitro ubiquitination assay confirmed that Clb6 is a substrate for APC(Cdh1). A KEN box and a destruction box in the Clb6N-terminus were identified. Mutations in the KEN box (mkb) and/or the destruction box (mdb) enhanced Clb6 stability in G1. Expression of Clb6mkd, bearing both mutations in the mkb and mdb, allowed cells to bypass the late G1 arrest caused by cdc4-1. This bypass phenotype was observed to depend upon CDK phosphorylation at residues S6, T39 and S147. Compared to Clb6, overexpression of Clb6ST, bearing all five mutations of S6A, T39A, S147A, mkb and mdb in combination, had a greater effect on promoting expression of Clb2 and S-phase entry, caused a greater G2 delay and a greater defect in cell division. Swe1 was also required for bud emergence when Clb6ST was overexpressed. Our observations suggest that both APC(Cdh1) and SCF(Cdc4)-dependent proteolysis of Clb6 at the G1/S border are crucial for multiple cell cycle regulated events including proper expression of Clb2, the G1/S and G2/M cell cycle transitions and for proper completion of cell division at mitotic exit.
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Affiliation(s)
- Shiao-Yii Wu
- Master Program in Microbiology and Immunology, Tzu-Chi University, Hualien, Taiwan
| | - Vivian Jen-Wei Kuan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yao-Wei Tzeng
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
| | - Scott C Schuyler
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Colorectal Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
| | - Yue-Li Juang
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan.
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8
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Al-Zain A, Schroeder L, Sheglov A, Ikui AE. Cdc6 degradation requires phosphodegron created by GSK-3 and Cdk1 for SCFCdc4 recognition in Saccharomyces cerevisiae. Mol Biol Cell 2015. [PMID: 25995377 DOI: 10.1091/mbc.e14-07-1213/asset/images/large/mbc-26-2609-g005.jpeg] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To ensure genome integrity, DNA replication takes place only once per cell cycle and is tightly controlled by cyclin-dependent kinase (Cdk1). Cdc6p is part of the prereplicative complex, which is essential for DNA replication. Cdc6 is phosphorylated by cyclin-Cdk1 to promote its degradation after origin firing to prevent DNA rereplication. We previously showed that a yeast GSK-3 homologue, Mck1 kinase, promotes Cdc6 degradation in a SCF(Cdc4)-dependent manner, therefore preventing rereplication. Here we present evidence that Mck1 directly phosphorylates a GSK-3 consensus site in the C-terminus of Cdc6. The Mck1-dependent Cdc6 phosphorylation required priming by cyclin/Cdk1 at an adjacent CDK consensus site. The sequential phosphorylation by Mck1 and Clb2/Cdk1 generated a Cdc4 E3 ubiquitin ligase-binding motif to promote Cdc6 degradation during mitosis. We further revealed that Cdc6 degradation triggered by Mck1 kinase was enhanced upon DNA damage caused by the alkylating agent methyl methanesulfonate and that the resulting degradation was mediated through Cdc4. Thus, Mck1 kinase ensures proper DNA replication, prevents DNA damage, and maintains genome integrity by inhibiting Cdc6.
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Affiliation(s)
- Amr Al-Zain
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Lea Schroeder
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Alina Sheglov
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Amy E Ikui
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
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9
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Al-Zain A, Schroeder L, Sheglov A, Ikui AE. Cdc6 degradation requires phosphodegron created by GSK-3 and Cdk1 for SCFCdc4 recognition in Saccharomyces cerevisiae. Mol Biol Cell 2015; 26:2609-19. [PMID: 25995377 PMCID: PMC4501359 DOI: 10.1091/mbc.e14-07-1213] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 05/12/2015] [Indexed: 11/11/2022] Open
Abstract
DNA replication has to be tightly regulated to ensure genome integrity such that DNA replication takes place only once per cell cycle. The Cdc6 sequential phosphorylation by GSK-3 and Cdk1 creates a binding site for Cdc4 ubiquitin ligase to promote Cdc6 degradation. To ensure genome integrity, DNA replication takes place only once per cell cycle and is tightly controlled by cyclin-dependent kinase (Cdk1). Cdc6p is part of the prereplicative complex, which is essential for DNA replication. Cdc6 is phosphorylated by cyclin-Cdk1 to promote its degradation after origin firing to prevent DNA rereplication. We previously showed that a yeast GSK-3 homologue, Mck1 kinase, promotes Cdc6 degradation in a SCFCdc4-dependent manner, therefore preventing rereplication. Here we present evidence that Mck1 directly phosphorylates a GSK-3 consensus site in the C-terminus of Cdc6. The Mck1-dependent Cdc6 phosphorylation required priming by cyclin/Cdk1 at an adjacent CDK consensus site. The sequential phosphorylation by Mck1 and Clb2/Cdk1 generated a Cdc4 E3 ubiquitin ligase–binding motif to promote Cdc6 degradation during mitosis. We further revealed that Cdc6 degradation triggered by Mck1 kinase was enhanced upon DNA damage caused by the alkylating agent methyl methanesulfonate and that the resulting degradation was mediated through Cdc4. Thus, Mck1 kinase ensures proper DNA replication, prevents DNA damage, and maintains genome integrity by inhibiting Cdc6.
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Affiliation(s)
- Amr Al-Zain
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Lea Schroeder
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Alina Sheglov
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Amy E Ikui
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
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10
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Grabowska E, Wronska U, Denkiewicz M, Jaszczur M, Respondek A, Alabrudzinska M, Suski C, Makiela-Dzbenska K, Jonczyk P, Fijalkowska IJ. Proper functioning of the GINS complex is important for the fidelity of DNA replication in yeast. Mol Microbiol 2014; 92:659-80. [PMID: 24628792 DOI: 10.1111/mmi.12580] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2014] [Indexed: 12/26/2022]
Abstract
The role of replicative DNA polymerases in ensuring genome stability is intensively studied, but the role of other components of the replisome is still not fully understood. One of such component is the GINS complex (comprising the Psf1, Psf2, Psf3 and Sld5 subunits), which participates in both initiation and elongation of DNA replication. Until now, the understanding of the physiological role of GINS mostly originated from biochemical studies. In this article, we present genetic evidence for an essential role of GINS in the maintenance of replication fidelity in Saccharomyces cerevisiae. In our studies we employed the psf1-1 allele (Takayama et al., 2003) and a novel psf1-100 allele isolated in our laboratory. Analysis of the levels and specificity of mutations in the psf1 strains indicates that the destabilization of the GINS complex or its impaired interaction with DNA polymerase epsilon increases the level of spontaneous mutagenesis and the participation of the error-prone DNA polymerase zeta. Additionally, a synergistic mutator effect was found for the defects in Psf1p and in the proofreading activity of Pol epsilon, suggesting that proper functioning of GINS is crucial for facilitating error-free processing of terminal mismatches created by Pol epsilon.
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Affiliation(s)
- Ewa Grabowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland
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11
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Liang L, Haug JS, Seidel CW, Gibson MC. Functional genomic analysis of the periodic transcriptome in the developing Drosophila wing. Dev Cell 2014; 29:112-27. [PMID: 24684830 DOI: 10.1016/j.devcel.2014.02.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 11/27/2013] [Accepted: 02/25/2014] [Indexed: 12/26/2022]
Abstract
The eukaryotic cell cycle, driven by both transcriptional and posttranslational mechanisms, is the central molecular oscillator underlying tissue growth throughout animals. Although genome-wide studies have investigated cell-cycle-associated transcription in unicellular systems, global patterns of periodic transcription in multicellular tissues remain largely unexplored. Here we define the cell-cycle-associated transcriptome of the developing Drosophila wing epithelium and compare it with that of cultured Drosophila S2 cells, revealing a core set of periodic genes and a surprising degree of context specificity in periodic transcription. We further employ RNAi-mediated phenotypic profiling to define functional requirements for more than 300 periodic genes, with a focus on those required for cell proliferation in vivo. Finally, we investigate uncharacterized genes required for interkinetic nuclear migration. Combined, these findings provide a global perspective on cell-cycle control in vivo, and they highlight a critical need to understand the context-specific regulation of cell proliferation.
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Affiliation(s)
- Liang Liang
- Stowers Institute for Medical Research, 1000 East 50(th) Street, Kansas City, MO 64110, USA
| | - Jeffrey S Haug
- Stowers Institute for Medical Research, 1000 East 50(th) Street, Kansas City, MO 64110, USA
| | - Chris W Seidel
- Stowers Institute for Medical Research, 1000 East 50(th) Street, Kansas City, MO 64110, USA
| | - Matthew C Gibson
- Stowers Institute for Medical Research, 1000 East 50(th) Street, Kansas City, MO 64110, USA; Department of Anatomy and Cell Biology, Kansas University Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA.
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Rossio V, Michimoto T, Sasaki T, Ohbayashi I, Kikuchi Y, Yoshida S. Nuclear PP2A-Cdc55 prevents APC-Cdc20 activation during the spindle assembly checkpoint. J Cell Sci 2013; 126:4396-405. [PMID: 23886942 DOI: 10.1242/jcs.127365] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cdc55, a regulatory B-subunit of protein phosphatase 2A (PP2A) complex, is essential for the spindle assembly checkpoint (SAC) in budding yeast, but the regulation and molecular targets of PP2A-Cdc55 have not been clearly defined or are controversial. Here, we show that an important target of Cdc55 in the SAC is the anaphase-promoting complex (APC) coupled with Cdc20 and that APC-Cdc20 is kept inactive by dephosphorylation by nuclear PP2A-Cdc55 when spindle is damaged. By isolating a new class of Cdc55 mutants specifically defective in the SAC and by artificially manipulating nucleocytoplasmic distribution of Cdc55, we further show that nuclear Cdc55 is essential for the SAC. Because the Cdc55-binding proteins Zds1 and Zds2 inhibit both nuclear accumulation of Cdc55 and SAC activity, we propose that spatial control of PP2A by Zds1 family proteins is important for tight control of SAC and mitotic progression.
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Affiliation(s)
- Valentina Rossio
- Department of Biology and Rosenstiel Basic Biomedical Sciences Research Center, Brandeis University, 415 South Street, Waltham, MA 02454, USA
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13
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Koltovaya NA. Involvement of cyclin-dependent kinase CDK1/CDC28 in regulation of cell cycle. RUSS J GENET+ 2013. [DOI: 10.1134/s1022795413050086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Yim H, Park JW, Woo SU, Kim ST, Liu L, Lee CH, Lee SK. Phosphorylation of Cdc6 at serine 74, but not at serine 106, drives translocation of Cdc6 to the cytoplasm. J Cell Physiol 2013; 228:1221-8. [PMID: 23129444 DOI: 10.1002/jcp.24275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 10/19/2012] [Indexed: 11/08/2022]
Abstract
Phosphorylation-dependent cytoplasmic translocation of human Cdc6 during S phase is sufficient to control its activity after origin firing. Export from the nucleus also serves as a mechanism for preventing re-replication in mammalian cells. Phosphorylation of the CDK consensus serine residues 54, 74, and 106 has been suggested to be involved in the cytoplasmic translocation of Cdc6. To determine the relative importance of the three phosphorylation sites, we have generated Cdc6 variants by substituting one or more of the three serine residues with alanine or aspartic acid and have assessed their cytoplasmic translocation behavior. Phosphorylation of serine 74 mainly contributes to the cytoplasmic translocation of Cdc6, while serine 54 phosphorylation provides a minor contribution. In contrast, phosphorylation at serine 106 does not affect the nuclear export of Cdc6. Comparative results were found in cells coexpressing the phosphorylation defective mutants of Cdc6 and cyclin A as well as in non-transfected cells synchronized by their release from a double thymidine block. We conclude that Cdk-mediated phosphorylation of Cdc6 at serine 74 is required for the cytoplasmic translocalization of Cdc6 during the cell cycle. Phosphorylation of Cdc6 at serine 54 plays a minor role and phosphorylation of serine 106 plays no role in the cytoplasmic localization of Cdc6. The phosphorylation of S74 in Cdc6 could be important for binding to the nuclear export protein for translocalization.
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Affiliation(s)
- Hyungshin Yim
- Division of Pharmaceutical Biosciences, Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Republic of Korea.
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Yim H, Erikson RL. Regulation of the final stage of mitosis by components of the pre-replicative complex and a polo kinase. Cell Cycle 2011; 10:1374-7. [PMID: 21519187 PMCID: PMC3117042 DOI: 10.4161/cc.10.9.15489] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 11/19/2022] Open
Abstract
The accurate division of duplicated DNA is essential for maintenance of genomic stability in proliferating eukaryotic cells. Errors in DNA replication and chromosomal segregation may lead to cell death or genomic mutations that lead to oncogenic properties. Thus, tight regulation of DNA replication and mitosis is essential for maintaining genomic integrity. Cell division cycle 6 (Cdc6) is an essential factor for initiating DNA replication. Recent work shows that phosphorylation of Cdc6 by polo-like kinase 1 (Plk1), one of the essential mitotic kinases, regulates mitotic exit mediated by Cdk1 and separase. Here we discuss how pre-replicative complex factors are connected with Plk1 and affect mitotic exit.
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Affiliation(s)
- Hyungshin Yim
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
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16
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Yim H, Erikson RL. Cell division cycle 6, a mitotic substrate of polo-like kinase 1, regulates chromosomal segregation mediated by cyclin-dependent kinase 1 and separase. Proc Natl Acad Sci U S A 2010; 107:19742-7. [PMID: 21041660 PMCID: PMC2993418 DOI: 10.1073/pnas.1013557107] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defining the links between cell division and DNA replication is essential for understanding normal cell cycle progression and tumorigenesis. In this report we explore the effect of phosphorylation of cell division cycle 6 (Cdc6), a DNA replication initiation factor, by polo-like kinase 1 (Plk1) on the regulation of chromosomal segregation. In mitosis, the phosphorylation of Cdc6 was highly increased, in correlation with the level of Plk1, and conversely, Cdc6 is hypophosphorylated in Plk1-depleted cells, although cyclin A- and cyclin B1-dependent kinases are active. Binding between Cdc6 and Plk1 occurs through the polo-box domain of Plk1, and Cdc6 is phosphorylated by Plk1 on T37. Immunohistochemistry studies reveal that Cdc6 and Plk1 colocalize to the central spindle in anaphase. Expression of T37V mutant of Cdc6 (Cdc6-TV) induces binucleated cells and incompletely separated nuclei. Wild-type Cdc6 but not Cdc6-TV binds cyclin-dependent kinase 1 (Cdk1). Expression of wild-type Plk1 but not kinase-defective mutant promotes the binding of Cdc6 to Cdk1. Cells expressing wild-type Cdc6 display lower Cdk1 activity and higher separase activity than cells expressing Cdc6-TV. These results suggest that Plk1-mediated phosphorylation of Cdc6 promotes the interaction of Cdc6 and Cdk1, leading to the attenuation of Cdk1 activity, release of separase, and subsequent anaphase progression.
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Affiliation(s)
- Hyungshin Yim
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Raymond L. Erikson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
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Kawakami H, Katayama T. DnaA, ORC, and Cdc6: similarity beyond the domains of life and diversity. Biochem Cell Biol 2010; 88:49-62. [PMID: 20130679 DOI: 10.1139/o09-154] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
To initiate chromosomal DNA replication, specific proteins bind to the replication origin region and form multimeric and dynamic complexes. Bacterial DnaA, the eukaryotic origin recognition complex (ORC), and Cdc6 proteins, most of which include an AAA+(-like) motif, play crucial roles in replication initiation. The importance of ATP binding and hydrolysis in these proteins has recently become recognized. ATP binding of Escherichia coli DnaA is required for the formation of the activated form of a DnaA multimer on the replication origin. The ATP-DnaA multimer can unwind duplex DNA in an origin-dependent manner, which is supported by various specific functions of several AAA+ motifs. DnaA-ATP hydrolysis is stimulated after initiation, repressing extra initiations, and sustaining once-per-cell cycle replication. ATP binding of ORC and Cdc6 in Saccharomyces cerevisiae is required for heteromultimeric complex formation and specific DNA binding. ATP hydrolysis of these proteins is important for the efficient loading of the minichromosome maintenance protein complex, a component of the putative replicative helicase. In this review, we discuss the roles of DnaA, ORC, and Cdc6 in replication initiation and its regulation. We also summarize the functional features of the AAA+ domains of these proteins, and the functional divergence of ORC in chromosomal dynamics.
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Affiliation(s)
- Hironori Kawakami
- Cold Spring Harbor Laboratory, 1 Bungtown Rd., Cold Spring Harbor, NY 11724, USA.
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Clift D, Bizzari F, Marston AL. Shugoshin prevents cohesin cleavage by PP2A(Cdc55)-dependent inhibition of separase. Genes Dev 2009; 23:766-80. [PMID: 19299562 PMCID: PMC2661608 DOI: 10.1101/gad.507509] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Accepted: 02/02/2009] [Indexed: 10/21/2022]
Abstract
Chromosome segregation is triggered by separase, an enzyme that cleaves cohesin, the protein complex that holds sister chromatids together. Separase activation requires the destruction of its inhibitor, securin, which occurs only upon the correct attachment of chromosomes to the spindle. However, other mechanisms restrict separase activity to the appropriate window in the cell cycle because cohesin is cleaved in a timely manner in securin-deficient cells. We investigated the mechanism by which the protector protein Shugoshin counteracts cohesin cleavage in budding yeast. We show that Shugoshin can prevent separase activation independently of securin. Instead, PP2A(Cdc55) is essential for Shugoshin-mediated inhibition of separase. Loss of both securin and Cdc55 leads to premature sister chromatid separation, resulting in aneuploidy. We propose that Cdc55 is a separase inhibitor that acts downstream from Shugoshin under conditions where sister chromatids are not under tension.
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Affiliation(s)
- Dean Clift
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - Farid Bizzari
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - 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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In-silico modeling of the mitotic spindle assembly checkpoint. PLoS One 2008; 3:e1555. [PMID: 18253502 PMCID: PMC2215771 DOI: 10.1371/journal.pone.0001555] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 01/14/2008] [Indexed: 01/28/2023] Open
Abstract
Background The Mitotic Spindle Assembly Checkpoint (MSAC) is an evolutionary conserved mechanism that ensures the correct segregation of chromosomes by restraining cell cycle progression from entering anaphase until all chromosomes have made proper bipolar attachments to the mitotic spindle. Its malfunction can lead to cancer. Principle Findings We have constructed and validated for the human MSAC mechanism an in silico dynamical model, integrating 11 proteins and complexes. The model incorporates the perspectives of three central control pathways, namely Mad1/Mad2 induced Cdc20 sequestering based on the Template Model, MCC formation, and APC inhibition. Originating from the biochemical reactions for the underlying molecular processes, non-linear ordinary differential equations for the concentrations of 11 proteins and complexes of the MSAC are derived. Most of the kinetic constants are taken from literature, the remaining four unknown parameters are derived by an evolutionary optimization procedure for an objective function describing the dynamics of the APC:Cdc20 complex. MCC:APC dissociation is described by two alternatives, namely the “Dissociation” and the “Convey” model variants. The attachment of the kinetochore to microtubuli is simulated by a switching parameter silencing those reactions which are stopped by the attachment. For both, the Dissociation and the Convey variants, we compare two different scenarios concerning the microtubule attachment dependent control of the dissociation reaction. Our model is validated by simulation of ten perturbation experiments. Conclusion Only in the controlled case, our models show MSAC behaviour at meta- to anaphase transition in agreement with experimental observations. Our simulations revealed that for MSAC activation, Cdc20 is not fully sequestered; instead APC is inhibited by MCC binding.
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Dpb2p, a noncatalytic subunit of DNA polymerase epsilon, contributes to the fidelity of DNA replication in Saccharomyces cerevisiae. Genetics 2008; 178:633-47. [PMID: 18245343 DOI: 10.1534/genetics.107.082818] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Most replicases are multi-subunit complexes. DNA polymerase epsilon from Saccharomyces cerevisiae is composed of four subunits: Pol2p, Dpb2p, Dpb3p, and Dpb4p. Pol2p and Dpb2p are essential. To investigate a possible role for the Dpb2p subunit in maintaining the fidelity of DNA replication, we isolated temperature-sensitive mutants in the DPB2 gene. Several of the newly isolated dpb2 alleles are strong mutators, exhibiting mutation rates equivalent to pol2 mutants defective in the 3' --> 5' proofreading exonuclease (pol2-4) or to mutants defective in mismatch repair (msh6). The dpb2 pol2-4 and dpb2 msh6 double mutants show a synergistic increase in mutation rate, indicating that the mutations arising in the dpb2 mutants are due to DNA replication errors normally corrected by mismatch repair. The dpb2 mutations decrease the affinity of Dpb2p for the Pol2p subunit as measured by two-hybrid analysis, providing a possible mechanistic explanation for the loss of high-fidelity synthesis. Our results show that DNA polymerase subunits other than those housing the DNA polymerase and 3' --> 5' exonuclease are essential in controlling the level of spontaneous mutagenesis and genetic stability in yeast cells.
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21
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Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Plesca D, Crosby ME, Gupta D, Almasan A. E2F4 function in G2: maintaining G2-arrest to prevent mitotic entry with damaged DNA. Cell Cycle 2007; 6:1147-52. [PMID: 17507799 PMCID: PMC2596058 DOI: 10.4161/cc.6.10.4259] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Mammalian cells undergo cell cycle arrest in response to DNA damage through multiple checkpoint mechanisms. One such checkpoint pathway maintains genomic integrity by delaying mitotic progression in response to genotoxic stress. Transition though the G2 phase and entry into mitosis is considered to be regulated primarily by cyclin B1 and its associated catalytically active partner Cdk1. While not necessary for its initiation, the p130 and Rb-dependent target genes have emerged as being important for stable maintenance of a G2 arrest. It was recently demonstrated that by interacting with p130, E2F4 is present in the nuclei and plays a key role in the maintenance of this stable G2 arrest. Increased E2F4 levels and its translocation to the nucleus following genotoxic stress result in downregulation of many mitotic genes and as a result promote a G0-like state. Irradiation of E2F4-depleted cells leads to enhanced cellular DNA double-strand breaks that may be measured by comet assays. It also results in cell death that is characterized by caspase activation, sub-G1 and sub-G2 DNA content, and decreased clonogenic cell survival. Here we review these recent findings and discuss the mechanisms of G2 phase checkpoint activation and maintenance with a particular focus on E2F4.
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Affiliation(s)
- Dragos Plesca
- Department of Cancer Biology; The Lerner Research Institute; Cleveland, Ohio USA
- School of Biomedical Sciences; Kent State University; Kent, Ohio USA
| | - Meredith E. Crosby
- Department of Environmental Health Sciences; Case Western Reserve University; Cleveland, Ohio USA
| | - Damodar Gupta
- Department of Cancer Biology; The Lerner Research Institute; Cleveland, Ohio USA
- Department of Radiation Oncology; Cleveland Clinic; Cleveland, Ohio USA
| | - Alexandru Almasan
- Department of Cancer Biology; The Lerner Research Institute; Cleveland, Ohio USA
- Department of Radiation Oncology; Cleveland Clinic; Cleveland, Ohio USA
- Correspondence to: Alexandru Almasan; Departments of Cancer Biology and Radiation Oncology; Lerner Research Institute; Cleveland Clinic; 9500 Euclid Avenue, Cleveland, Ohio 44195 USA; Tel.: 216.444.9970; Fax: 216.445.6269;
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