1
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Keaton JM, Workman BG, Xie L, Paulson JR. Analog-sensitive Cdk1 as a tool to study mitotic exit: protein phosphatase 1 is required downstream from Cdk1 inactivation in budding yeast. Chromosome Res 2023; 31:27. [PMID: 37690059 DOI: 10.1007/s10577-023-09736-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/17/2023] [Accepted: 08/23/2023] [Indexed: 09/12/2023]
Abstract
We show that specific inactivation of the protein kinase Cdk1/cyclin B (Cdc28/Clb2) triggers exit from mitosis in the budding yeast Saccharomyces cerevisiae. Cells carrying the allele cdc28-as1, which makes Cdk1 (Cdc28) uniquely sensitive to the ATP analog 1NM-PP1, were arrested with spindle poisons and then treated with 1NM-PP1 to inhibit Cdk1. This caused the cells to leave mitosis and enter G1-phase as shown by initiation of rebudding (without cytokinesis), induction of mating projections ("shmoos") by α-factor, stabilization of Sic1, and degradation of Clb2. It is known that Cdk1 must be inactivated for cells to exit mitosis, but our results show that inactivation of Cdk1 is not only necessary but also sufficient to initiate the transition from mitosis to G1-phase. This result suggests a system in which to test requirements for particular gene products downstream from Cdk1 inactivation, for example, by combining cdc28-as1 with conditional mutations in the genes of interest. Using this approach, we demonstrate that protein phosphatase 1 (PPase1; Glc7 in S. cerevisiae) is required for mitotic exit and reestablishment of interphase following Cdk1 inactivation. This system could be used to test the need for other protein phosphatases downstream from Cdk1 inactivation, such as PPase 2A and Cdc14, and it could be combined with phosphoproteomics to gain information about the substrates that the various phosphatases act upon during mitotic exit.
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Affiliation(s)
- Jason M Keaton
- Acacia Safety Consulting, Inc, P.O. Box 342603, Milwaukee, WI, 53234, USA
- Department of Chemistry, University of Wisconsin-Oshkosh, Oshkosh, WI, 54901, USA
| | - Benjamin G Workman
- Department of Chemistry, University of Wisconsin-Oshkosh, Oshkosh, WI, 54901, USA
| | - Linfeng Xie
- Department of Chemistry, University of Wisconsin-Oshkosh, Oshkosh, WI, 54901, USA
| | - James R Paulson
- Department of Chemistry, University of Wisconsin-Oshkosh, Oshkosh, WI, 54901, USA.
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2
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Keaton JM, Workman BG, Xie L, Paulson JR. Exit from Mitosis in Budding Yeast: Protein Phosphatase 1 is Required Downstream from Cdk1 Inactivation. RESEARCH SQUARE 2023:rs.3.rs-2787001. [PMID: 37090579 PMCID: PMC10120774 DOI: 10.21203/rs.3.rs-2787001/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
We show that inactivation of the protein kinase Cdk1/Cyclin B (Cdc28/Clb 2 in the budding yeast Saccharomyces cerevisiae ) is not only necessary for cells to leave mitosis, as is well known, but also sufficient to trigger mitotic exit. Cells carrying the mutation cdc28-as1 , which makes Cdc28 (Cdk1) uniquely sensitive to the ATP analog 1NM-PP1, were arrested with spindle poisons and then treated with 1NM-PP1 to inhibit Cdk1. This treatment caused the cells to exit mitosis and enter G1-phase as shown by initiation of rebudding (without cytokinesis), production of "shmoos" (when α-factor was present), stabilization of Sic1, and degradation of Clb2. This result provides a system in which to test whether particular gene products are required downstream from Cdk1 inactivation in exit from mitosis. In this system, the mutation cdc28-as1 is combined with a conditional mutation in the gene of interest. Using this approach, we demonstrate that Protein Phosphatase 1 (PPase1; Glc7 in S. cerevisiae ) is required for reestablishment of G1-phase following Cdk1 inactivation. This system could be used to test whether other protein phosphatases are also needed downstream from Cdk1 inactivation, and it could be combined with phosphoproteomics to gain information about the substrates those phosphatases act on during mitotic exit.
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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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Devault A, Piatti S. Downregulation of the Tem1 GTPase by Amn1 after cytokinesis involves both nuclear import and SCF-mediated degradation. J Cell Sci 2021; 134:272157. [PMID: 34518877 DOI: 10.1242/jcs.258972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/03/2021] [Indexed: 11/20/2022] Open
Abstract
At mitotic exit the cell cycle engine is reset to allow crucial processes, such as cytokinesis and replication origin licensing, to take place before a new cell cycle begins. In budding yeast, the cell cycle clock is reset by a Hippo-like kinase cascade called the mitotic exit network (MEN), whose activation is triggered at spindle pole bodies (SPBs) by the Tem1 GTPase. Yet, MEN activity must be extinguished once MEN-dependent processes have been accomplished. One factor contributing to switching off the MEN is the Amn1 protein, which binds Tem1 and inhibits it through an unknown mechanism. Here, we show that Amn1 downregulates Tem1 through a dual mode of action. On one side, it evicts Tem1 from SPBs and escorts it into the nucleus. On the other, it promotes Tem1 degradation as part of a Skp, Cullin and F-box-containing (SCF) ubiquitin ligase. Tem1 inhibition by Amn1 takes place after cytokinesis in the bud-derived daughter cell, consistent with its asymmetric appearance in the daughter cell versus the mother cell. This dual mechanism of Tem1 inhibition by Amn1 may contribute to the rapid extinguishing of MEN activity once it has fulfilled its functions.
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Affiliation(s)
- Alain Devault
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS (Centre National de la Recherche Scientifique), 1919 Route de Mende, 34293 Montpellier, France
| | - Simonetta Piatti
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS (Centre National de la Recherche Scientifique), 1919 Route de Mende, 34293 Montpellier, France
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5
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Alonso-Ramos P, Álvarez-Melo D, Strouhalova K, Pascual-Silva C, Garside GB, Arter M, Bermejo T, Grigaitis R, Wettstein R, Fernández-Díaz M, Matos J, Geymonat M, San-Segundo PA, Carballo JA. The Cdc14 Phosphatase Controls Resolution of Recombination Intermediates and Crossover Formation during Meiosis. Int J Mol Sci 2021; 22:ijms22189811. [PMID: 34575966 PMCID: PMC8470964 DOI: 10.3390/ijms22189811] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 12/15/2022] Open
Abstract
Meiotic defects derived from incorrect DNA repair during gametogenesis can lead to mutations, aneuploidies and infertility. The coordinated resolution of meiotic recombination intermediates is required for crossover formation, ultimately necessary for the accurate completion of both rounds of chromosome segregation. Numerous master kinases orchestrate the correct assembly and activity of the repair machinery. Although much less is known, the reversal of phosphorylation events in meiosis must also be key to coordinate the timing and functionality of repair enzymes. Cdc14 is a crucial phosphatase required for the dephosphorylation of multiple CDK1 targets in many eukaryotes. Mutations that inactivate this phosphatase lead to meiotic failure, but until now it was unknown if Cdc14 plays a direct role in meiotic recombination. Here, we show that the elimination of Cdc14 leads to severe defects in the processing and resolution of recombination intermediates, causing a drastic depletion in crossovers when other repair pathways are compromised. We also show that Cdc14 is required for the correct activity and localization of the Holliday Junction resolvase Yen1/GEN1. We reveal that Cdc14 regulates Yen1 activity from meiosis I onwards, and this function is essential for crossover resolution in the absence of other repair pathways. We also demonstrate that Cdc14 and Yen1 are required to safeguard sister chromatid segregation during the second meiotic division, a late action that is independent of the earlier role in crossover formation. Thus, this work uncovers previously undescribed functions of the evolutionary conserved Cdc14 phosphatase in the regulation of meiotic recombination.
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Affiliation(s)
- Paula Alonso-Ramos
- Center for Biological Research Margarita Salas, Department of Cellular and Molecular Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (P.A.-R.); (D.Á.-M.); (K.S.); (C.P.-S.); (T.B.); (M.F.-D.)
| | - David Álvarez-Melo
- Center for Biological Research Margarita Salas, Department of Cellular and Molecular Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (P.A.-R.); (D.Á.-M.); (K.S.); (C.P.-S.); (T.B.); (M.F.-D.)
| | - Katerina Strouhalova
- Center for Biological Research Margarita Salas, Department of Cellular and Molecular Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (P.A.-R.); (D.Á.-M.); (K.S.); (C.P.-S.); (T.B.); (M.F.-D.)
- Department of Cell Biology, Charles University, Viničná 7, 12843 Prague, Czech Republic
| | - Carolina Pascual-Silva
- Center for Biological Research Margarita Salas, Department of Cellular and Molecular Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (P.A.-R.); (D.Á.-M.); (K.S.); (C.P.-S.); (T.B.); (M.F.-D.)
| | - George B. Garside
- Genome Damage and Stability Centre, University of Sussex, Brighton BN1 4DY, UK;
- Leibniz Institute for Age Research/Fritz Lipmann Institute (FLI), Beutenbergstr. 11, D-07745 Jena, Germany
| | - Meret Arter
- Institute of Biochemistry, HPM D6.5-ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; (M.A.); (R.G.); (R.W.); (J.M.)
- Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Teresa Bermejo
- Center for Biological Research Margarita Salas, Department of Cellular and Molecular Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (P.A.-R.); (D.Á.-M.); (K.S.); (C.P.-S.); (T.B.); (M.F.-D.)
| | - Rokas Grigaitis
- Institute of Biochemistry, HPM D6.5-ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; (M.A.); (R.G.); (R.W.); (J.M.)
- Max Perutz Labs, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Rahel Wettstein
- Institute of Biochemistry, HPM D6.5-ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; (M.A.); (R.G.); (R.W.); (J.M.)
- Max Perutz Labs, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Marta Fernández-Díaz
- Center for Biological Research Margarita Salas, Department of Cellular and Molecular Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (P.A.-R.); (D.Á.-M.); (K.S.); (C.P.-S.); (T.B.); (M.F.-D.)
| | - Joao Matos
- Institute of Biochemistry, HPM D6.5-ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; (M.A.); (R.G.); (R.W.); (J.M.)
- Max Perutz Labs, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Marco Geymonat
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK;
| | - Pedro A. San-Segundo
- Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC) and University of Salamanca, 37007 Salamanca, Spain;
| | - Jesús A. Carballo
- Center for Biological Research Margarita Salas, Department of Cellular and Molecular Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (P.A.-R.); (D.Á.-M.); (K.S.); (C.P.-S.); (T.B.); (M.F.-D.)
- Correspondence:
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6
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Touati SA, Hofbauer L, Jones AW, Snijders AP, Kelly G, Uhlmann F. Cdc14 and PP2A Phosphatases Cooperate to Shape Phosphoproteome Dynamics during Mitotic Exit. Cell Rep 2020; 29:2105-2119.e4. [PMID: 31722221 PMCID: PMC6857435 DOI: 10.1016/j.celrep.2019.10.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 09/27/2019] [Accepted: 10/10/2019] [Indexed: 12/22/2022] Open
Abstract
Temporal control over protein phosphorylation and dephosphorylation is crucial for accurate chromosome segregation and for completion of the cell division cycle during exit from mitosis. In budding yeast, the Cdc14 phosphatase is thought to be a major regulator at this time, while in higher eukaryotes PP2A phosphatases take a dominant role. Here, we use time-resolved phosphoproteome analysis in budding yeast to evaluate the respective contributions of Cdc14, PP2ACdc55, and PP2ARts1. This reveals an overlapping requirement for all three phosphatases during mitotic progression. Our time-resolved phosphoproteome resource reveals how Cdc14 instructs the sequential pattern of phosphorylation changes, in part through preferential recognition of serine-based cyclin-dependent kinase (Cdk) substrates. PP2ACdc55 and PP2ARts1 in turn exhibit a broad substrate spectrum with some selectivity for phosphothreonines and a role for PP2ARts1 in sustaining Aurora kinase activity. These results illustrate synergy and coordination between phosphatases as they orchestrate phosphoproteome dynamics during mitotic progression. Cdc14, PP2ACdc55, and PP2ARts1 phosphatases cooperate during budding yeast mitosis Cdc14 targets serine Cdk motifs for rapid dephosphorylation PP2ACdc55 dephosphorylates Cdk and Plk substrates on threonine residues PP2ARts1 displays regulatory crosstalk with Aurora kinase
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Affiliation(s)
- Sandra A Touati
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
| | - Lorena Hofbauer
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Andrew W Jones
- Mass Spectrometry Proteomics Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Ambrosius P Snijders
- Mass Spectrometry Proteomics Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Gavin Kelly
- Bioinformatics & Biostatistics Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
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7
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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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8
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Control of Eukaryotic DNA Replication Initiation-Mechanisms to Ensure Smooth Transitions. Genes (Basel) 2019; 10:genes10020099. [PMID: 30700044 PMCID: PMC6409694 DOI: 10.3390/genes10020099] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 02/06/2023] Open
Abstract
DNA replication differs from most other processes in biology in that any error will irreversibly change the nature of the cellular progeny. DNA replication initiation, therefore, is exquisitely controlled. Deregulation of this control can result in over-replication characterized by repeated initiation events at the same replication origin. Over-replication induces DNA damage and causes genomic instability. The principal mechanism counteracting over-replication in eukaryotes is a division of replication initiation into two steps—licensing and firing—which are temporally separated and occur at distinct cell cycle phases. Here, we review this temporal replication control with a specific focus on mechanisms ensuring the faultless transition between licensing and firing phases.
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9
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Tamborrini D, Juanes MA, Ibanes S, Rancati G, Piatti S. Recruitment of the mitotic exit network to yeast centrosomes couples septin displacement to actomyosin constriction. Nat Commun 2018; 9:4308. [PMID: 30333493 PMCID: PMC6193047 DOI: 10.1038/s41467-018-06767-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 09/10/2018] [Indexed: 01/11/2023] Open
Abstract
In many eukaryotic organisms cytokinesis is driven by a contractile actomyosin ring (CAR) that guides membrane invagination. What triggers CAR constriction at a precise time of the cell cycle is a fundamental question. In budding yeast CAR is assembled via a septin scaffold at the division site. A Hippo-like kinase cascade, the Mitotic Exit Network (MEN), promotes mitotic exit and cytokinesis, but whether and how these two processes are independently controlled by MEN is poorly understood. Here we show that a critical function of MEN is to promote displacement of the septin ring from the division site, which in turn is essential for CAR constriction. This is independent of MEN control over mitotic exit and involves recruitment of MEN components to the spindle pole body (SPB). Ubiquitination of the SPB scaffold Nud1 inhibits MEN signaling at the end of mitosis and prevents septin ring splitting, thus silencing the cytokinetic machinery. The Mitotic Exit Network (MEN) promotes mitotic exit and cytokinesis but if and how MEN independently controls these two processes is unclear. Here, the authors report that MEN displaces septins from the cell division site to promote actomyosin ring constriction, independently of MEN control of mitotic exit.
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Affiliation(s)
- Davide Tamborrini
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), 1919 Route de Mende, 34293, Montpellier, France.,Max-Planck-Institute of Molecular Physiology, Otto-Hahn Str. 11, 44227, Dortmund, Germany
| | - Maria Angeles Juanes
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), 1919 Route de Mende, 34293, Montpellier, France.,Brandeis University, 415 South Street, Waltham, MA, 02454, USA
| | - Sandy Ibanes
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), 1919 Route de Mende, 34293, Montpellier, France
| | - Giulia Rancati
- Institute of Medical Biology, 8a Biomedical Grove, Singapore, 138648, Singapore
| | - Simonetta Piatti
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), 1919 Route de Mende, 34293, Montpellier, France.
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10
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Powers BL, Hall MC. Re-examining the role of Cdc14 phosphatase in reversal of Cdk phosphorylation during mitotic exit. J Cell Sci 2017; 130:2673-2681. [PMID: 28663385 DOI: 10.1242/jcs.201012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 06/26/2017] [Indexed: 01/12/2023] Open
Abstract
Inactivation of cyclin-dependent kinase (Cdk) and reversal of Cdk phosphorylation are universally required for mitotic exit. In budding yeast (Saccharomyces cerevisiae), Cdc14 is essential for both and thought to be the major Cdk-counteracting phosphatase. However, Cdc14 is not required for mitotic exit in many eukaryotes, despite highly conserved biochemical properties. The question of how similar enzymes could have such disparate influences on mitotic exit prompted us to re-examine the contribution of budding yeast Cdc14. By using an auxin-inducible degron, we show that severe Cdc14 depletion has no effect on the kinetics of mitotic exit and bulk Cdk substrate dephosphorylation, but causes a cell separation defect and is ultimately lethal. Phosphoproteomic analysis revealed that Cdc14 is highly selective for distinct Cdk sites in vivo and does not catalyze widespread Cdk substrate dephosphorylation. We conclude that additional phosphatases likely contribute substantially to Cdk substrate dephosphorylation and coordination of mitotic exit in budding yeast, similar to in other eukaryotes, and the critical mitotic exit functions of Cdc14 require trace amounts of enzyme. We propose that Cdc14 plays very specific, and often different, roles in counteracting Cdk phosphorylation in all species.
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Affiliation(s)
- Brendan L Powers
- Department of Biochemistry and Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - Mark C Hall
- Department of Biochemistry and Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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11
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Dmowski M, Fijałkowska IJ. Diverse roles of Dpb2, the non-catalytic subunit of DNA polymerase ε. Curr Genet 2017; 63:983-987. [PMID: 28516230 PMCID: PMC5668336 DOI: 10.1007/s00294-017-0706-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 12/18/2022]
Abstract
Timely progression of living cells through the cell cycle is precisely regulated. This involves a series of phosphorylation events which are regulated by various cyclins, activated in coordination with the cell cycle progression. Phosphorylated proteins govern cell growth, division as well as duplication of the genetic material and transcriptional activation of genes involved in these processes. A subset of these tightly regulated genes, which depend on the MBF transcription factor and are mainly involved in DNA replication and cell division, is transiently activated at the transition from G1 to S phase. A Saccharomyces cerevisiae mutant in the Dpb2 non-catalytic subunit of DNA polymerase ε (Polε) demonstrates abnormalities in transcription of MBF-dependent genes even in normal growth conditions. It is, therefore, tempting to speculate that Dpb2 which, as described previously, participates in the early stages of DNA replication initiation, has an impact on the regulation of replication-related genes expression with possible implications for genomic stability.
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Affiliation(s)
- Michał Dmowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
| | - Iwona J Fijałkowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
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12
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Reusswig KU, Zimmermann F, Galanti L, Pfander B. Robust Replication Control Is Generated by Temporal Gaps between Licensing and Firing Phases and Depends on Degradation of Firing Factor Sld2. Cell Rep 2016; 17:556-569. [DOI: 10.1016/j.celrep.2016.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 08/10/2016] [Accepted: 09/02/2016] [Indexed: 10/20/2022] Open
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13
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Method for identifying phosphorylated substrates of specific cyclin/cyclin-dependent kinase complexes. Proc Natl Acad Sci U S A 2014; 111:11323-8. [PMID: 25049391 DOI: 10.1073/pnas.1409666111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In eukaryotes, cell cycle progression is controlled by cyclin/cyclin-dependent kinase (CDK) pairs. To better understand the details of this process, it is necessary to dissect the CDK's substrate pool in a cyclin- and cell cycle stage-specific way. Here, we report a mass spectrometry-based method that couples rapid isolation of native kinase-substrate complexes to on-bead phosphorylation with heavy-labeled ATP (ATP-γ-(18)O4). This combined in vivo/in vitro method was developed for identifying cyclin/CDK substrates together with their sites of phosphorylation. We used the method to identify Clb5 (S-cyclin)/Cdc28 and Cln2 (G1/S-cyclin)/Cdc28 substrates during S phase in Saccharomyces cerevisiae (Cdc28 is the master CDK in budding yeast). During the work, we discovered that Clb5/Cdc28 specifically phosphorylates S429 in the disordered tail of Cdc14, an essential phosphatase antagonist of Cdc28. This phosphorylation severely decreases the activity of Cdc14, providing a means for modulating the balance of CDK and phosphatase activity.
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14
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Zhao W, Yang X, Dong S, Sheng Y, Wang Y, Zheng X. Transient silencing mediated by in vitro synthesized double-stranded RNA indicates that PsCdc14 is required for sporangial development in a soybean root rot pathogen. SCIENCE CHINA. LIFE SCIENCES 2011; 54:1143-50. [PMID: 22227907 DOI: 10.1007/s11427-011-4250-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 10/18/2011] [Indexed: 11/27/2022]
Abstract
In many eukaryotic organisms, Cdc14 phosphatase regulates multiple biological events during anaphase and is essential for mitosis. It has been shown that Cdc14 is required for sporulation in the potato blight pathogen Phytophthora infestans; however, the role that the Cdc14 homolog (PsCdc14) plays in the soil-borne soybean root rot pathogen P. sojae remains ambiguous. PsCdc14 is highly expressed in sporulation, zoospore, and cyst life stages, but not in vegetative mycelia and infection stages, suggesting that it contributes to asexual reproduction and thus the spread of the disease. Double-stranded RNA (dsRNA) mediates gene silencing, a post-transcriptional and highly conserved process in eukaryotes, involving specific gene silencing through degradation of target mRNA. We combined in vitro dsRNA synthesis and a polyethylene glycol-mediated transformation system to construct a dsRNA-mediated transient gene silencing system; and then performed a functional analysis of PsCdc14 in P. sojae. PsCdc14 mRNA was dramatically reduced in transformants after protoplasts were exposed in in vitro synthesized PsCdc14 dsRNA, resulting in low sporangial production and abnormal development in P. sojae silencing lines. Furthermore, dsRNA-mediated transient gene silencing could enable elucidation of P. sojae rapid gene function, facilitating our understanding of the development and pathogenicity mechanisms of this oomycete fungus.
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Affiliation(s)
- Wei Zhao
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education of China, Nanjing Agricultural University, Nanjing 210095, China
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15
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Chin CF, Bennett AM, Ma WK, Hall MC, Yeong FM. Dependence of Chs2 ER export on dephosphorylation by cytoplasmic Cdc14 ensures that septum formation follows mitosis. Mol Biol Cell 2011; 23:45-58. [PMID: 22072794 PMCID: PMC3248903 DOI: 10.1091/mbc.e11-05-0434] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sequestration of Cdc14 from the cytoplasm ensures Chs2 ER retention after MEN activation. The interdependence of chromosome segregation, MEN activation, decrease in mitotic CDK activity, and Cdc14 dispersal provides an effective mechanism for cells to order late mitotic events. Cytokinesis, which leads to the physical separation of two dividing cells, is normally restrained until after nuclear division. In Saccharomyces cerevisiae, chitin synthase 2 (Chs2), which lays down the primary septum at the mother–daughter neck, also ensures proper actomyosin ring constriction during cytokinesis. During the metaphase-to-anaphase transition, phosphorylation of Chs2 by the mitotic cyclin-dependent kinase (Cdk1) retains Chs2 at the endoplasmic reticulum (ER), thereby preventing its translocation to the neck. Upon Cdk1 inactivation at the end of mitosis, Chs2 is exported from the ER and targeted to the neck. The mechanism for triggering Chs2 ER export thus far is unknown. We show here that Chs2 ER export requires the direct reversal of the inhibitory Cdk1 phosphorylation sites by Cdc14 phosphatase, the ultimate effector of the mitotic exit network (MEN). We further show that only Cdc14 liberated by the MEN after completion of chromosome segregation, and not Cdc14 released in early anaphase by the Cdc fourteen early anaphase release pathway, triggers Chs2 ER exit. Presumably, the reduced Cdk1 activity in late mitosis further favors dephosphorylation of Chs2 by Cdc14. Thus, by requiring declining Cdk1 activity and Cdc14 nuclear release for Chs2 ER export, cells ensure that septum formation is contingent upon chromosome separation and exit from mitosis.
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Affiliation(s)
- Cheen Fei Chin
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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16
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Mocciaro A, Schiebel E. Cdc14: a highly conserved family of phosphatases with non-conserved functions? J Cell Sci 2011; 123:2867-76. [PMID: 20720150 DOI: 10.1242/jcs.074815] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
CDC14 was originally identified by L. Hartwell in his famous screen for genes that regulate the budding yeast cell cycle. Subsequent work showed that Cdc14 belongs to a family of highly conserved dual-specificity phosphatases that are present in a wide range of organisms from yeast to human. Human CDC14B is even able to fulfill the essential functions of budding yeast Cdc14. In budding yeast, Cdc14 counteracts the activity of cyclin dependent kinase (Cdk1) at the end of mitosis and thus has important roles in the regulation of anaphase, mitotic exit and cytokinesis. On the basis of the functional conservation of other cell-cycle genes it seemed obvious to assume that Cdc14 phosphatases also have roles in late mitosis in mammalian cells and regulate similar targets to those found in yeast. However, analysis of the human Cdc14 proteins (CDC14A, CDC14B and CDC14C) by overexpression or by depletion using small interfering RNA (siRNA) has suggested functions that are quite different from those of ScCdc14. Recent studies in avian and human somatic cell lines in which the gene encoding either Cdc14A or Cdc14B had been deleted, have shown - surprisingly - that neither of the two phosphatases on its own is essential for viability, cell-cycle progression and checkpoint control. In this Commentary, we critically review the available data on the functions of yeast and vertebrate Cdc14 phosphatases, and discuss whether they indeed share common functions as generally assumed.
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Affiliation(s)
- Annamaria Mocciaro
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69117 Heidelberg, Germany
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17
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Bloom J, Cristea IM, Procko AL, Lubkov V, Chait BT, Snyder M, Cross FR. Global analysis of Cdc14 phosphatase reveals diverse roles in mitotic processes. J Biol Chem 2010; 286:5434-45. [PMID: 21127052 DOI: 10.1074/jbc.m110.205054] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cdc14 phosphatase regulates multiple events during anaphase and is essential for mitotic exit in budding yeast. Cdc14 is regulated in both a spatial and temporal manner. It is sequestered in the nucleolus for most of the cell cycle by the nucleolar protein Net1 and is released into the nucleus and cytoplasm during anaphase. To identify novel binding partners of Cdc14, we used affinity purification of Cdc14 and mass spectrometric analysis of interacting proteins from strains in which Cdc14 localization or catalytic activity was altered. To alter Cdc14 localization, we used a strain deleted for NET1, which causes full release of Cdc14 from the nucleolus. To alter Cdc14 activity, we generated mutations in the active site of Cdc14 (C283S or D253A), which allow binding of substrates, but not dephosphorylation, by Cdc14. Using this strategy, we identified new interactors of Cdc14, including multiple proteins involved in mitotic events. A subset of these proteins displayed increased affinity for catalytically inactive mutants of Cdc14 compared with the wild-type version, suggesting they are likely substrates of Cdc14. We have also shown that several of the novel Cdc14-interacting proteins, including Kar9 (a protein that orients the mitotic spindle) and Bni1 and Bnr1 (formins that nucleate actin cables and may be important for actomyosin ring contraction) are specifically dephosphorylated by Cdc14 in vitro and in vivo. Our findings suggest the dephosphorylation of the formins may be important for their observed localization change during exit from mitosis and indicate that Cdc14 targets proteins involved in wide-ranging mitotic events.
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Affiliation(s)
- Joanna Bloom
- The Rockefeller University, New York, New York 10065, USA
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18
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Zhai Y, Yung PYK, Huo L, Liang C. Cdc14p resets the competency of replication licensing by dephosphorylating multiple initiation proteins during mitotic exit in budding yeast. J Cell Sci 2010; 123:3933-43. [DOI: 10.1242/jcs.075366] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In eukaryotes, replication licensing is achieved through sequential loading of several replication-initiation proteins onto replication origins to form pre-replicative complexes (pre-RCs), and unscheduled replication licensing is prevented by cyclin-dependent kinases (CDKs) through inhibitory phosphorylations of multiple initiation proteins. It is known that CDK inactivation during mitotic exit promotes pre-RC formation for the next cell cycle. However, whether the removal of the inhibitory phosphorylations on the initiation proteins is essential and the identity of the acting phosphatase(s) remain unknown. Here, we show that cell division cycle protein 14 (Cdc14p) dephosphorylates replication-initiation proteins Orc2p, Orc6p, Cdc6p and Mcm3p to restore their competence for pre-RC assembly in the budding yeast Saccharomyces cerevisiae. Cells without functional Cdc14p fail to dephosphorylate initiation proteins and to form pre-RCs – even when CDK activities are suppressed – and cannot replicate DNA in mitotic rereplication systems, whereas pulsed ectopic expression of Cdc14p in mitotic cells results in efficient pre-RC assembly and DNA rereplication. Furthermore, Cdc14p becomes dispensable for DNA rereplication in mitotic cells with combined non-phosphorylatable and/or phosphorylation-insensitive alleles of the initiation proteins. These data unravel the essential role of Cdc14p in replication licensing, beyond its established functions in mitotic exit, providing new insight into the intricate regulation of DNA replication through the interplay of CDKs and the Cdc14p phosphatase.
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Affiliation(s)
- Yuanliang Zhai
- Section of Biochemistry and Cell Biology, Division of Life Science, and Center for Cancer Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Philip Y. K. Yung
- Section of Biochemistry and Cell Biology, Division of Life Science, and Center for Cancer Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Lin Huo
- Section of Biochemistry and Cell Biology, Division of Life Science, and Center for Cancer Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Chun Liang
- Section of Biochemistry and Cell Biology, Division of Life Science, and Center for Cancer Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Abstract
Recent data show that cells from many cancers exhibit massive chromosome instability. The traditional view is that the gradual accumulation of mutations in genes involved in transcriptional regulation and cell cycle controls results in tumor development. This, however, does not exclude the possibility that some mutations could be more potent than others in destabilizing the genome by targeting both chromosomal integrity and corresponding checkpoint mechanisms simultaneously. Three such examples of "single-hit" lesions potentially leading to heritable genome destabilization are discussed. They include: failure to release sister chromatid cohesion due to the incomplete proteolytic cleavage of cohesin; massive merotelic kinetochore misattachments upon condensin depletion; and chromosome under-replication. In all three cases, cells fail to detect potential chromosomal bridges before anaphase entry, indicating that there is a basic cell cycle requirement to maintain a degree of sister chromatid bridging that is not recognizable as chromosomal damage.
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Affiliation(s)
- Alexander V Strunnikov
- Laboratory of Immunopathology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 5640 Fishers Lane, Room 1524, Rockville, MD 20852, USA.
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20
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Brümmer A, Salazar C, Zinzalla V, Alberghina L, Höfer T. Mathematical modelling of DNA replication reveals a trade-off between coherence of origin activation and robustness against rereplication. PLoS Comput Biol 2010; 6:e1000783. [PMID: 20485558 PMCID: PMC2869307 DOI: 10.1371/journal.pcbi.1000783] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 04/13/2010] [Indexed: 01/08/2023] Open
Abstract
Eukaryotic genomes are duplicated from multiple replication origins exactly once per cell cycle. In Saccharomyces cerevisiae, a complex molecular network has been identified that governs the assembly of the replication machinery. Here we develop a mathematical model that links the dynamics of this network to its performance in terms of rate and coherence of origin activation events, number of activated origins, the resulting distribution of replicon sizes and robustness against DNA rereplication. To parameterize the model, we use measured protein expression data and systematically generate kinetic parameter sets by optimizing the coherence of origin firing. While randomly parameterized networks yield unrealistically slow kinetics of replication initiation, networks with optimized parameters account for the experimentally observed distribution of origin firing times. Efficient inhibition of DNA rereplication emerges as a constraint that limits the rate at which replication can be initiated. In addition to the separation between origin licensing and firing, a time delay between the activation of S phase cyclin-dependent kinase (S-Cdk) and the initiation of DNA replication is required for preventing rereplication. Our analysis suggests that distributive multisite phosphorylation of the S-Cdk targets Sld2 and Sld3 can generate both a robust time delay and contribute to switch-like, coherent activation of replication origins. The proposed catalytic function of the complex formed by Dpb11, Sld3 and Sld2 strongly enhances coherence and robustness of origin firing. The model rationalizes how experimentally observed inefficient replication from fewer origins is caused by premature activation of S-Cdk, while premature activity of the S-Cdk targets Sld2 and Sld3 results in DNA rereplication. Thus the model demonstrates how kinetic deregulation of the molecular network governing DNA replication may result in genomic instability.
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Affiliation(s)
- Anneke Brümmer
- Research Group Modelling of Biological Systems (B086), German Cancer Research Center, Heidelberg, Germany
- BioQuant Center, Heidelberg, Germany
| | - Carlos Salazar
- Research Group Modelling of Biological Systems (B086), German Cancer Research Center, Heidelberg, Germany
- BioQuant Center, Heidelberg, Germany
| | | | - Lilia Alberghina
- Department of Biotechnology and Biosciences, Università degli Studi di Milano-Bicocca, Milan, Italy
- * E-mail: (LA); (TH)
| | - Thomas Höfer
- Research Group Modelling of Biological Systems (B086), German Cancer Research Center, Heidelberg, Germany
- BioQuant Center, Heidelberg, Germany
- * E-mail: (LA); (TH)
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21
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Dulev S, de Renty C, Mehta R, Minkov I, Schwob E, Strunnikov A. Essential global role of CDC14 in DNA synthesis revealed by chromosome underreplication unrecognized by checkpoints in cdc14 mutants. Proc Natl Acad Sci U S A 2009; 106:14466-71. [PMID: 19666479 PMCID: PMC2723162 DOI: 10.1073/pnas.0900190106] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Indexed: 12/27/2022] Open
Abstract
The CDC14 family of multifunctional evolutionarily conserved phosphatases includes major regulators of mitosis in eukaryotes and of DNA damage response in humans. The CDC14 function is also crucial for accurate chromosome segregation, which is exemplified by its absolute requirement in yeast for the anaphase segregation of nucleolar organizers; however the nature of this essential pathway is not understood. Upon investigation of the rDNA nondisjunction phenomenon, it was found that cdc14 mutants fail to complete replication of this locus. Moreover, other late-replicating genomic regions (10% of the genome) are also underreplicated in cdc14 mutants undergoing anaphase. This selective genome-wide replication defect is due to dosage insufficiency of replication factors in the nucleus, which stems from two defects, both contingent on the reduced CDC14 function in the preceding mitosis. First, a constitutive nuclear import defect results in a drastic dosage decrease for those replication proteins that are regulated by nuclear transport. Particularly, essential RPA subunits display both lower mRNA and protein levels, as well as abnormal cytoplasmic localization. Second, the reduced transcription of MBF and SBF-controlled genes in G1 leads to the reduction in protein levels of many proteins involved in DNA replication. The failure to complete replication of late replicons is the primary reason for chromosome nondisjunction upon CDC14 dysfunction. As the genome-wide slow-down of DNA replication does not trigger checkpoints [Lengronne A, Schwob E (2002) Mol Cell 9:1067-1078], CDC14 mutations pose an overwhelming challenge to genome stability, both generating chromosome damage and undermining the checkpoint control mechanisms.
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MESH Headings
- Active Transport, Cell Nucleus
- Anaphase/genetics
- Blotting, Western
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Nucleus/metabolism
- Chromatin Immunoprecipitation
- Chromosome Segregation
- Chromosomes, Fungal/genetics
- DNA Damage
- DNA Replication
- DNA, Fungal/biosynthesis
- DNA, Fungal/genetics
- DNA, Ribosomal/genetics
- G1 Phase/genetics
- Genes, Essential/genetics
- Genes, Essential/physiology
- Genome, Fungal/genetics
- Genome-Wide Association Study
- Models, Biological
- Mutation
- Protein Binding
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/metabolism
- Replication Protein A/genetics
- Replication Protein A/metabolism
- S Phase/genetics
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
- Transcription, Genetic
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Affiliation(s)
- Stanimir Dulev
- National Institutes of Health, National Institute of Child Health and Human Development, Bethesda, Maryland, 20892
- University of Plovdiv, Plovdiv 4000, Bulgaria
| | - Christelle de Renty
- Institute of Molecular Genetics, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5535, University Montpellier 2, 34293, France; and
| | - Rajvi Mehta
- National Institutes of Health, National Institute of Child Health and Human Development, Bethesda, Maryland, 20892
| | - Ivan Minkov
- University of Plovdiv, Plovdiv 4000, Bulgaria
| | - Etienne Schwob
- Institute of Molecular Genetics, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5535, University Montpellier 2, 34293, France; and
| | - Alexander Strunnikov
- National Institutes of Health, National Institute of Child Health and Human Development, Bethesda, Maryland, 20892
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22
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Taxis C, Stier G, Spadaccini R, Knop M. Efficient protein depletion by genetically controlled deprotection of a dormant N-degron. Mol Syst Biol 2009; 5:267. [PMID: 19401679 PMCID: PMC2683728 DOI: 10.1038/msb.2009.25] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 03/17/2009] [Indexed: 11/20/2022] Open
Abstract
Methods that allow for the manipulation of genes or their products have been highly fruitful for biomedical research. Here, we describe a method that allows the control of protein abundance by a genetically encoded regulatory system. We developed a dormant N-degron that can be attached to the N-terminus of a protein of interest. Upon expression of a site-specific protease, the dormant N-degron becomes deprotected. The N-degron then targets itself and the attached protein for rapid proteasomal degradation through the N-end rule pathway. We use an optimized tobacco etch virus (TEV) protease variant combined with selective target binding to achieve complete and rapid deprotection of the N-degron-tagged proteins. This method, termed TEV protease induced protein inactivation (TIPI) of TIPI-degron (TDeg) modified target proteins is fast, reversible, and applicable to a broad range of proteins. TIPI of yeast proteins essential for vegetative growth causes phenotypes that are close to deletion mutants. The features of the TIPI system make it a versatile tool to study protein function in eukaryotes and to create new modules for synthetic or systems biology.
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Affiliation(s)
- Christof Taxis
- EMBL, Cell Biology and Biophysics Unit, Meyerhofstr. 1, Heidelberg, Germany
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23
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Jwa M, Kim JH, Chan CSM. Regulation of Sli15/INCENP, kinetochore, and Cdc14 phosphatase functions by the ribosome biogenesis protein Utp7. ACTA ACUST UNITED AC 2008; 182:1099-111. [PMID: 18794331 PMCID: PMC2542472 DOI: 10.1083/jcb.200802085] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Sli15–Ipl1–Bir1 chromosomal passenger complex is essential for proper kinetochore–microtubule attachment and spindle stability in the budding yeast Saccharomyces cerevisiae. During early anaphase, release of the Cdc14 protein phosphatase from the nucleolus leads to the dephosphorylation of Sli15 and redistribution of this complex from kinetochores to the spindle. We show here that the predominantly nucleolar ribosome biogenesis protein Utp7 is also present at kinetochores and is required for normal organization of kinetochore proteins and proper chromosome segregation. Utp7 associates with and regulates the localization of Sli15 and Cdc14. Before anaphase onset, it prevents the premature nucleolar release of Cdc14 and the premature concentration of Sli15 on the spindle. Furthermore, Utp7 can regulate the localization and phosphorylation status of Sli15 independent of its effect on Cdc14 function. Thus, Utp7 is a multifunctional protein that plays essential roles in the vital cellular processes of ribosome biogenesis, chromosome segregation, and cell cycle control.
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Affiliation(s)
- Miri Jwa
- Institute for Cellular and Molecular Biology, The University of Texas, Austin, TX 78712, USA
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24
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Pursell ZF, Kunkel TA. DNA polymerase epsilon: a polymerase of unusual size (and complexity). PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2008; 82:101-45. [PMID: 18929140 PMCID: PMC3694787 DOI: 10.1016/s0079-6603(08)00004-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zachary F. Pursell
- Laboratory of Molecular Genetics and Laboratory of Structural Biology National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709
| | - Thomas A. Kunkel
- Laboratory of Molecular Genetics and Laboratory of Structural Biology National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709
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25
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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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26
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Abstract
Recent advances in understanding bacterial cell-cycle regulation suggest circuit control mechanisms that operate analogously to those in the eukaryotic cell cycle.
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Affiliation(s)
- Joseph C Chen
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, California 94132, USA
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