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Yuki R, Ikeda Y, Yasutake R, Saito Y, Nakayama Y. SH2D4A promotes centrosome maturation to support spindle microtubule formation and mitotic progression. Sci Rep 2023; 13:2067. [PMID: 36739326 PMCID: PMC9899277 DOI: 10.1038/s41598-023-29362-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/02/2023] [Indexed: 02/06/2023] Open
Abstract
Mitotic progression requires the precise formation of spindle microtubules based on mature centrosomes. During the G2/M transition, centrosome maturation progresses, and associated microtubules bundle to form mitotic spindle fibers and capture the chromosomes for alignment at the cell equator. Mitotic kinases-induced phosphorylation signaling is necessary for these processes. Here, we identified SH2 domain-containing protein 4A (SH2D4A/PPP1R38) as a new mitotic regulator. SH2D4A knockdown delays mitotic progression. The time-lapse imaging analysis showed that SH2D4A specifically contributes to the alignment of chromosomes. The cold treatment assay and microtubule regrowth assay indicated that SH2D4A promotes microtubule nucleation to support kinetochore-microtubule attachment. This may be due to the centrosome maturation by SH2D4A via centrosomal recruitment of pericentriolar material (PCM) such as cep192, γ-tubulin, and PLK1. SH2D4A was found to be a negative regulator of PP1 phosphatase. Consistently, treatment with a PP1 inhibitor rescues SH2D4A-knockdown-induced phenotypes, including the microtubule nucleation and centrosomal recruitment of active PLK1. These results suggest that SH2D4A is involved in PCM recruitment to centrosomes and centrosome maturation through attenuation of PP1 phosphatases, accelerating the spindle formation and supporting mitotic progression.
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Affiliation(s)
- Ryuzaburo Yuki
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan.
| | - Yuki Ikeda
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan
| | - Ryuji Yasutake
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan
| | - Youhei Saito
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan
| | - Yuji Nakayama
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan.
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2
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Fan X, Kraynak J, Knisely JPS, Formenti SC, Shen WH. PTEN as a Guardian of the Genome: Pathways and Targets. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a036194. [PMID: 31932469 DOI: 10.1101/cshperspect.a036194] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Faithful transmission of genetic information is only possible with the structural and functional integrity of the genome. PTEN has been recognized as a guardian of the genome since the identification of its noncanonical localization and function in the nucleus. Yet, the role of PTEN in guarding the genome relies on integration of diverse mechanisms elicited by its canonical activity in antagonizing PI3K as well as emerging noncanonical functions. In the nucleus, PTEN maintains the structural integrity of chromosomes and the architecture of heterochromatin by physically interacting with chromosomal and nucleosomal components. PTEN also controls the functional integrity of key genetic transmission machineries by promoting proper assembly of the replisome and mitotic spindles. Deregulation of PTEN signaling impairs genome integrity, leading to spontaneous replication/mitotic stress and subsequent stress tolerance. Identification of novel targets of PTEN signaling and illumination of the interplay of diverse PTEN pathways in genome maintenance will help us better understand mechanisms underlying tumor evolution and therapeutic resistance.
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Affiliation(s)
- Xinyi Fan
- Department of Radiation Oncology, Weill Cornell Medicine, Cornell University, New York, New York 10065, USA
| | - Jeffrey Kraynak
- Department of Radiation Oncology, Weill Cornell Medicine, Cornell University, New York, New York 10065, USA
| | - Jonathan P S Knisely
- Department of Radiation Oncology, Weill Cornell Medicine, Cornell University, New York, New York 10065, USA
| | - Silvia C Formenti
- Department of Radiation Oncology, Weill Cornell Medicine, Cornell University, New York, New York 10065, USA.,Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, Cornell University, New York, New York 10065, USA
| | - Wen H Shen
- Department of Radiation Oncology, Weill Cornell Medicine, Cornell University, New York, New York 10065, USA.,Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, Cornell University, New York, New York 10065, USA
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3
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Ovejero S, Bueno A, Sacristán MP. Working on Genomic Stability: From the S-Phase to Mitosis. Genes (Basel) 2020; 11:E225. [PMID: 32093406 PMCID: PMC7074175 DOI: 10.3390/genes11020225] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/15/2022] Open
Abstract
Fidelity in chromosome duplication and segregation is indispensable for maintaining genomic stability and the perpetuation of life. Challenges to genome integrity jeopardize cell survival and are at the root of different types of pathologies, such as cancer. The following three main sources of genomic instability exist: DNA damage, replicative stress, and chromosome segregation defects. In response to these challenges, eukaryotic cells have evolved control mechanisms, also known as checkpoint systems, which sense under-replicated or damaged DNA and activate specialized DNA repair machineries. Cells make use of these checkpoints throughout interphase to shield genome integrity before mitosis. Later on, when the cells enter into mitosis, the spindle assembly checkpoint (SAC) is activated and remains active until the chromosomes are properly attached to the spindle apparatus to ensure an equal segregation among daughter cells. All of these processes are tightly interconnected and under strict regulation in the context of the cell division cycle. The chromosomal instability underlying cancer pathogenesis has recently emerged as a major source for understanding the mitotic processes that helps to safeguard genome integrity. Here, we review the special interconnection between the S-phase and mitosis in the presence of under-replicated DNA regions. Furthermore, we discuss what is known about the DNA damage response activated in mitosis that preserves chromosomal integrity.
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Affiliation(s)
- Sara Ovejero
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Institute of Human Genetics, CNRS, University of Montpellier, 34000 Montpellier, France
- Department of Biological Hematology, CHU Montpellier, 34295 Montpellier, France
| | - Avelino Bueno
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - María P. Sacristán
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
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4
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Lemmens B, Lindqvist A. DNA replication and mitotic entry: A brake model for cell cycle progression. J Cell Biol 2019; 218:3892-3902. [PMID: 31712253 PMCID: PMC6891093 DOI: 10.1083/jcb.201909032] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 12/22/2022] Open
Abstract
Lemmens and Lindqvist discuss how DNA replication and mitosis are coordinated and propose a cell cycle model controlled by brakes. The core function of the cell cycle is to duplicate the genome and divide the duplicated DNA into two daughter cells. These processes need to be carefully coordinated, as cell division before DNA replication is complete leads to genome instability and cell death. Recent observations show that DNA replication, far from being only a consequence of cell cycle progression, plays a key role in coordinating cell cycle activities. DNA replication, through checkpoint kinase signaling, restricts the activity of cyclin-dependent kinases (CDKs) that promote cell division. The S/G2 transition is therefore emerging as a crucial regulatory step to determine the timing of mitosis. Here we discuss recent observations that redefine the coupling between DNA replication and cell division and incorporate these insights into an updated cell cycle model for human cells. We propose a cell cycle model based on a single trigger and sequential releases of three molecular brakes that determine the kinetics of CDK activation.
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Affiliation(s)
- Bennie Lemmens
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet and Science for Life Laboratory, Stockholm, Sweden
| | - Arne Lindqvist
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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5
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Crncec A, Hochegger H. Triggering mitosis. FEBS Lett 2019; 593:2868-2888. [PMID: 31602636 DOI: 10.1002/1873-3468.13635] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/07/2019] [Accepted: 10/07/2019] [Indexed: 12/28/2022]
Abstract
Entry into mitosis is triggered by the activation of cyclin-dependent kinase 1 (Cdk1). This simple reaction rapidly and irreversibly sets the cell up for division. Even though the core step in triggering mitosis is so simple, the regulation of this cellular switch is highly complex, involving a large number of interconnected signalling cascades. We do have a detailed knowledge of most of the components of this network, but only a poor understanding of how they work together to create a precise and robust system that ensures that mitosis is triggered at the right time and in an orderly fashion. In this review, we will give an overview of the literature that describes the Cdk1 activation network and then address questions relating to the systems biology of this switch. How is the timing of the trigger controlled? How is mitosis insulated from interphase? What determines the sequence of events, following the initial trigger of Cdk1 activation? Which elements ensure robustness in the timing and execution of the switch? How has this system been adapted to the high levels of replication stress in cancer cells?
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Affiliation(s)
- Adrijana Crncec
- Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - Helfrid Hochegger
- Genome Damage and Stability Centre, University of Sussex, Brighton, UK
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6
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Murray JM, Carr AM. Integrating DNA damage repair with the cell cycle. Curr Opin Cell Biol 2018; 52:120-125. [PMID: 29587168 DOI: 10.1016/j.ceb.2018.03.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/06/2018] [Accepted: 03/14/2018] [Indexed: 10/17/2022]
Abstract
DNA is labile and constantly subject to damage. In addition to external mutagens, DNA is continuously damaged by the aqueous environment, cellular metabolites and is prone to strand breakage during replication. Cell duplication is orchestrated by the cell division cycle and specific DNA structures are processed differently depending on where in the cell cycle they are detected. This is often because a specific structure is physiological in one context, for example during DNA replication, while indicating a potentially pathological event in another, such as interphase or mitosis. Thus, contextualising the biochemical entity with respect to cell cycle progression provides information necessary to appropriately regulate DNA processing activities. We review the links between DNA repair and cell cycle context, drawing together recent advances.
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Affiliation(s)
- Johanne M Murray
- Genome Damage and Stability Centre, School of Life Sciences, University of Susses, Falmer BN1 9RQ, United Kingdom
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Susses, Falmer BN1 9RQ, United Kingdom.
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7
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Kettenbach AN, Schlosser KA, Lyons SP, Nasa I, Gui J, Adamo ME, Gerber SA. Global assessment of its network dynamics reveals that the kinase Plk1 inhibits the phosphatase PP6 to promote Aurora A activity. Sci Signal 2018; 11:eaaq1441. [PMID: 29764989 PMCID: PMC6002859 DOI: 10.1126/scisignal.aaq1441] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Polo-like kinase 1 (Plk1) is an essential protein kinase that promotes faithful mitotic progression in eukaryotes. The subcellular localization and substrate interactions of Plk1 are tightly controlled and require its binding to phosphorylated residues. To identify phosphorylation-dependent interactions within the Plk1 network in human mitotic cells, we performed quantitative proteomics on HeLa cells cultured with kinase inhibitors or expressing a Plk1 mutant that was deficient in phosphorylation-dependent substrate binding. We found that many interactions were abolished upon kinase inhibition; however, a subset was protected from phosphatase opposition or was unopposed, resulting in persistent interaction of the substrate with Plk1. This subset includes phosphoprotein phosphatase 6 (PP6), whose activity toward Aurora kinase A (Aurora A) was inhibited by Plk1. Our data suggest that this Plk1-PP6 interaction generates a feedback loop that coordinates and reinforces the activities of Plk1 and Aurora A during mitotic entry and is terminated by the degradation of Plk1 during mitotic exit. Thus, we have identified a mechanism for the previously puzzling observation of the Plk1-dependent regulation of Aurora A.
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Affiliation(s)
- Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Kate A Schlosser
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Scott P Lyons
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Isha Nasa
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Jiang Gui
- Department of Biomedical Data Science, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Mark E Adamo
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Scott A Gerber
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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8
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Battle LJ, Chambers TC. Small peptide substrates and high resolution peptide gels for the analysis of site-specific protein phosphorylation and dephosphorylation. J Biol Methods 2017; 4. [PMID: 29242808 PMCID: PMC5726596 DOI: 10.14440/jbm.2017.199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Protein phosphorylation and dephosphorylation reactions play key regulatory roles in many fundamental cellular processes. Due to the large number of kinases and phosphatases in the genome, the identification of the specific enzymes responsible for a given site in a given protein is immensely challenging. However, because protein kinases and phosphatases recognize local specificity determinants within proteins, it is possible to use small peptides to study the characteristics of site-specific phosphorylation. In addition, phosphorylation usually causes retardation in gel mobility, providing an opportunity to investigate peptide phosphorylation and dephosphorylation by monitoring migration on high resolution peptide gels. In this study, we demonstrate the utility of such a technique using small peptides corresponding to cyclin-dependent kinase-1 (Cdk1)/cyclin B1 sites in two important apoptotic regulatory proteins, Bcl-xL and caspase-9. We show that the mobility of the peptides is retarded following Cdk1-mediated phosphorylation, and that peptide dephosphorylation, catalyzed either by purified phosphatase or by crude cell extracts, is readily observable by increased peptide gel mobility. Furthermore, the procedure can be conducted without the use of radioactive adenosine triphosphate (ATP), and does not require any specialized reagents or apparatus. The method can be used to identify and characterize specific kinase and phosphatases responsible for phosphorylation and dephosphorylation of specific sites in any protein of interest.
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Affiliation(s)
- Laura Johnson Battle
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Timothy C Chambers
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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9
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Alexander KE, Rizkallah R. Aurora A Phosphorylation of YY1 during Mitosis Inactivates its DNA Binding Activity. Sci Rep 2017; 7:10084. [PMID: 28855673 PMCID: PMC5577188 DOI: 10.1038/s41598-017-10935-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/16/2017] [Indexed: 12/16/2022] Open
Abstract
Successful execution of mitotic cell division requires the tight synchronisation of numerous biochemical pathways. The underlying mechanisms that govern chromosome segregation have been thoroughly investigated. However, the mechanisms that regulate transcription factors in coordination with mitotic progression remain poorly understood. In this report, we identify the transcription factor YY1 as a novel mitotic substrate for the Aurora A kinase, a key regulator of critical mitotic events, like centrosome maturation and spindle formation. Using in vitro kinase assays, we show that Aurora A directly phosphorylates YY1 at serine 365 in the DNA-binding domain. Using a new phospho-specific antibody, we show that YY1 phosphorylation at serine 365 occurs during mitosis, and that this phosphorylation is significantly reduced upon inhibition of Aurora A. Furthermore, we show, using electrophoretic mobility shift and chromatin immunoprecipitation assays, that phosphorylation of YY1 at this site abolishes its DNA binding activity in vitro and in vivo. In conformity with this loss of binding activity, phosphorylated YY1 also loses its transctivation ability as demonstrated by a luciferase reporter assay. These results uncover a novel mechanism that implicates Aurora A in the mitotic inactivation of transcription factors.
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Affiliation(s)
- Karen E Alexander
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
| | - Raed Rizkallah
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America.
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10
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Closing a gap in the nuclear envelope. Curr Opin Cell Biol 2016; 40:90-97. [PMID: 27016712 DOI: 10.1016/j.ceb.2016.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/13/2016] [Accepted: 03/05/2016] [Indexed: 11/22/2022]
Abstract
The nuclear envelope (NE) ensures nucleo-cytoplasmic compartmentalization, with trafficking of macromolecules across this double membrane controlled by embedded nuclear pore complexes (NPCs). The NE and associated proteins are dismantled during open mitosis and reestablishment of this barrier during mitotic exit requires dynamic remodeling of endoplasmic reticulum (ER) membranes and coordination with NPC reformation, with NPC deposition continuing during subsequent interphase. In this review, we discuss recent progress in our understanding of NE reformation and nuclear pore complex generation, with special focus on work implicating the endosomal sorting complex required for transport (ESCRT) membrane remodeling machinery in these events.
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11
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Rogers S, Fey D, McCloy RA, Parker BL, Mitchell NJ, Payne RJ, Daly RJ, James DE, Caldon CE, Watkins DN, Croucher DR, Burgess A. PP1 initiates the dephosphorylation of MASTL, triggering mitotic exit and bistability in human cells. J Cell Sci 2016; 129:1340-54. [PMID: 26872783 PMCID: PMC4852720 DOI: 10.1242/jcs.179754] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 02/08/2016] [Indexed: 12/23/2022] Open
Abstract
Entry into mitosis is driven by the phosphorylation of thousands of substrates, under the master control of Cdk1. During entry into mitosis, Cdk1, in collaboration with MASTL kinase, represses the activity of the major mitotic protein phosphatases, PP1 and PP2A, thereby ensuring mitotic substrates remain phosphorylated. For cells to complete and exit mitosis, these phosphorylation events must be removed, and hence, phosphatase activity must be reactivated. This reactivation of phosphatase activity presumably requires the inhibition of MASTL; however, it is not currently understood what deactivates MASTL and how this is achieved. In this study, we identified that PP1 is associated with, and capable of partially dephosphorylating and deactivating, MASTL during mitotic exit. Using mathematical modelling, we were able to confirm that deactivation of MASTL is essential for mitotic exit. Furthermore, small decreases in Cdk1 activity during metaphase are sufficient to initiate the reactivation of PP1, which in turn partially deactivates MASTL to release inhibition of PP2A and, hence, create a feedback loop. This feedback loop drives complete deactivation of MASTL, ensuring a strong switch-like activation of phosphatase activity during mitotic exit.
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Affiliation(s)
- Samuel Rogers
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia
| | - Dirk Fey
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland
| | - Rachael A McCloy
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia
| | - Benjamin L Parker
- The Charles Perkins Centre, School of Molecular Bioscience and Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Nicholas J Mitchell
- School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Richard J Payne
- School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Roger J Daly
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences Monash University, Clayton, Victoria 3800, Australia
| | - David E James
- The Charles Perkins Centre, School of Molecular Bioscience and Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - C Elizabeth Caldon
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia St. Vincent's Clinical School, Faculty of Medicine, UNSW, Darlinghurst 2010, New South Wales, Australia
| | - D Neil Watkins
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia St. Vincent's Clinical School, Faculty of Medicine, UNSW, Darlinghurst 2010, New South Wales, Australia Department of Thoracic Medicine, St Vincent's Hospital, Darlinghurst, New South Wales 2010, Australia
| | - David R Croucher
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia St. Vincent's Clinical School, Faculty of Medicine, UNSW, Darlinghurst 2010, New South Wales, Australia
| | - Andrew Burgess
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia St. Vincent's Clinical School, Faculty of Medicine, UNSW, Darlinghurst 2010, New South Wales, Australia
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12
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Rizkallah R, Batsomboon P, Dudley GB, Hurt MM. Identification of the oncogenic kinase TOPK/PBK as a master mitotic regulator of C2H2 zinc finger proteins. Oncotarget 2015; 6:1446-61. [PMID: 25575812 PMCID: PMC4359306 DOI: 10.18632/oncotarget.2735] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/08/2014] [Indexed: 11/25/2022] Open
Abstract
TOPK/PBK is an oncogenic kinase upregulated in most human cancers and its high expression correlates with poor prognosis. TOPK is known to be activated by Cdk1 and needed for mitotic cell division; however, its mitotic functions are not yet fully understood. In this study, we show that TOPK plays a global mitotic role by simultaneously regulating hundreds of DNA binding proteins. C2H2 zinc finger proteins (ZFPs) constitute the largest family of human proteins. All C2H2 ZFPs contain a highly conserved linker sequence joining their multi-zinc finger domains. We have previously shown that phosphorylation of this conserved motif serves as a global mechanism for the coordinate dissociation of C2H2 ZFPs from condensing chromatin, during mitosis. Here, using a panel of kinase inhibitors, we identified K252a as a potent inhibitor of mitotic ZFP linker phosphorylation. We generated a biotinylated form of K252a and used it to purify candidate kinases. From these candidates we identified TOPK/PBK, in vitro and in vivo, as the master ZFP linker kinase. Furthermore, we show precise temporal correlation between TOPK activating phosphorylation by Cdk1 and linker phosphorylation in mitosis. The identification of this fundamental role of TOPK underscores its significance as a promising novel target of cancer therapeutics.
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Affiliation(s)
- Raed Rizkallah
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, 32306, United States of America
| | - Paratchata Batsomboon
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, 32306, United States of America
| | - Gregory B Dudley
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, 32306, United States of America
| | - Myra M Hurt
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, 32306, United States of America
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13
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Cobb MM, Austin DC, Sack JT, Trimmer JS. Cell Cycle-dependent Changes in Localization and Phosphorylation of the Plasma Membrane Kv2.1 K+ Channel Impact Endoplasmic Reticulum Membrane Contact Sites in COS-1 Cells. J Biol Chem 2015; 290:29189-201. [PMID: 26442584 DOI: 10.1074/jbc.m115.690198] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Indexed: 12/22/2022] Open
Abstract
The plasma membrane (PM) comprises distinct subcellular domains with diverse functions that need to be dynamically coordinated with intracellular events, one of the most impactful being mitosis. The Kv2.1 voltage-gated potassium channel is conditionally localized to large PM clusters that represent specialized PM:endoplasmic reticulum membrane contact sites (PM:ER MCS), and overexpression of Kv2.1 induces more exuberant PM:ER MCS in neurons and in certain heterologous cell types. Localization of Kv2.1 at these contact sites is dynamically regulated by changes in phosphorylation at one or more sites located on its large cytoplasmic C terminus. Here, we show that Kv2.1 expressed in COS-1 cells undergoes dramatic cell cycle-dependent changes in its PM localization, having diffuse localization in interphase cells, and robust clustering during M phase. The mitosis-specific clusters of Kv2.1 are localized to PM:ER MCS, and M phase clustering of Kv2.1 induces more extensive PM:ER MCS. These cell cycle-dependent changes in Kv2.1 localization and the induction of PM:ER MCS are accompanied by increased mitotic Kv2.1 phosphorylation at several C-terminal phosphorylation sites. Phosphorylation of exogenously expressed Kv2.1 is significantly increased upon metaphase arrest in COS-1 and CHO cells, and in a pancreatic β cell line that express endogenous Kv2.1. The M phase clustering of Kv2.1 at PM:ER MCS in COS-1 cells requires the same C-terminal targeting motif needed for conditional Kv2.1 clustering in neurons. The cell cycle-dependent changes in localization and phosphorylation of Kv2.1 were not accompanied by changes in the electrophysiological properties of Kv2.1 expressed in CHO cells. Together, these results provide novel insights into the cell cycle-dependent changes in PM protein localization and phosphorylation.
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Affiliation(s)
- Melanie M Cobb
- From the Departments of Neurobiology, Physiology, and Behavior
| | | | - Jon T Sack
- Physiology and Membrane Biology, and Anesthesiology and Pain Medicine, University of California Davis School of Medicine, Davis, California 95616
| | - James S Trimmer
- From the Departments of Neurobiology, Physiology, and Behavior, Physiology and Membrane Biology, and
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14
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Waraky A, Akopyan K, Parrow V, Strömberg T, Axelson M, Abrahmsén L, Lindqvist A, Larsson O, Aleem E. Picropodophyllin causes mitotic arrest and catastrophe by depolymerizing microtubules via insulin-like growth factor-1 receptor-independent mechanism. Oncotarget 2015; 5:8379-92. [PMID: 25268741 PMCID: PMC4226690 DOI: 10.18632/oncotarget.2292] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Picropodophyllin (PPP) is an anticancer drug undergoing clinical development in NSCLC. PPP has been shown to suppress IGF-1R signaling and to induce a G2/M cell cycle phase arrest but the exact mechanisms remain to be elucidated. The present study identified an IGF-1-independent mechanism of PPP leading to pro-metaphase arrest. The mitotic block was induced in human cancer cell lines and in an A549 xenograft mouse but did not occur in normal hepatocytes/mouse tissues. Cell cycle arrest by PPP occurred in vitro and in vivo accompanied by prominent CDK1 activation, and was IGF-1R-independent since it occurred also in IGF-1R-depleted and null cells. The tumor cells were not arrested in G2/M but in mitosis. Centrosome separation was prevented during mitotic entry, resulting in a monopolar mitotic spindle with subsequent prometaphase-arrest, independent of Plk1/Aurora A or Eg5, and leading to cell features of mitotic catastrophe. PPP also increased soluble tubulin and decreased spindle-associated tubulin within minutes, indicating that it interfered with microtubule dynamics. These results provide a novel IGF-1R-independent mechanism of antitumor effects of PPP.
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Affiliation(s)
- Ahmed Waraky
- Department of Oncology-Pathology, Cancer Center Karolinska, Solna, Sweden
| | - Karen Akopyan
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna, Sweden
| | - Vendela Parrow
- Axelar AB, Karolinska Institutet Science Park, Solna, Sweden
| | - Thomas Strömberg
- Department of Oncology-Pathology, Cancer Center Karolinska, Solna, Sweden
| | - Magnus Axelson
- Department of Clinical Chemistry, Karolinska Institutet, Stockholm, Sweden
| | - Lars Abrahmsén
- Axelar AB, Karolinska Institutet Science Park, Solna, Sweden
| | - Arne Lindqvist
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna, Sweden
| | - Olle Larsson
- Department of Oncology-Pathology, Cancer Center Karolinska, Solna, Sweden
| | - Eiman Aleem
- Department of Oncology-Pathology, Cancer Center Karolinska, Solna, Sweden. Alexandria University, Faculty of Science, Department of Zoology, Alexandria, Egypt. The Ronald A. Matricaria Institute of Molecular Medicine at Phoenix Children's Hospital, University of Arizona College of Medicine-Phoenix, Department of Child Health, Phoenix, Arizona, USA
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15
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From nature to bedside: Pro-survival and cell death mechanisms as therapeutic targets in cancer treatment. Biotechnol Adv 2014; 32:1111-22. [DOI: 10.1016/j.biotechadv.2014.03.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/04/2014] [Accepted: 03/04/2014] [Indexed: 12/11/2022]
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16
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Alvarez-Fernández M, Malumbres M. Preparing a cell for nuclear envelope breakdown: Spatio-temporal control of phosphorylation during mitotic entry. Bioessays 2014; 36:757-65. [PMID: 24889070 DOI: 10.1002/bies.201400040] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chromosome segregation requires the ordered separation of the newly replicated chromosomes between the two daughter cells. In most cells, this requires nuclear envelope (NE) disassembly during mitotic entry and its reformation at mitotic exit. Nuclear envelope breakdown (NEB) results in the mixture of two cellular compartments. This process is controlled through phosphorylation of multiple targets by cyclin-dependent kinase 1 (Cdk1)-cyclin B complexes as well as other mitotic enzymes. Experimental evidence also suggests that nucleo-cytoplasmic transport of critical cell cycle regulators such as Cdk1-cyclin B complexes or Greatwall, a kinase responsible for the inactivation of PP2A phosphatases, plays a major role in maintaining the boost of mitotic phosphorylation thus preventing the potential mitotic collapse derived from NEB. These data suggest the relevance of nucleo-cytoplasmic transport not only to communicate cytoplasmic and nuclear compartments during interphase, but also to prepare cells for the mixture of these two compartments during mitosis.
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17
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Ma L, Aslanian A, Sun H, Jin M, Shi Y, Yates JR, Hunter T. Identification of small ubiquitin-like modifier substrates with diverse functions using the Xenopus egg extract system. Mol Cell Proteomics 2014; 13:1659-75. [PMID: 24797264 DOI: 10.1074/mcp.m113.035626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Post-translational modification by SUMO is a highly conserved pathway in eukaryotes that plays very important regulatory roles in many cellular processes. Deregulation of the SUMO pathway contributes to the development and progression of many diseases including cancer. Therefore, identifying additional SUMO substrates and studying how their cellular and biological functions are regulated by sumoylation should provide new insights. Our studies showed that sumoylation activity was significant in Xenopus egg extracts, and that a high level of sumoylation was associated with sperm chromatin when SUMO was incubated with Xenopus egg extracts. By isolating SUMO-conjugated substrates using His-tagged SUMO1 or SUMO2 proteins under denaturing conditions, we identified 346 proteins by mass spectrometry analysis that were not present in control pull-downs. Among them, 167 proteins were identified from interphase egg extracts, 86 proteins from mitotic phase egg extracts, and 93 proteins from both. Thirty-three proteins were pulled down by SUMO1, 85 proteins by SUMO2, and 228 proteins by both. We validated the sumoylation of five candidates, CKB, ATXN10, BTF3, HABP4, and BZW1, by co-transfecting them along with SUMO in HEK293T cells. Gene ontology analysis showed that SUMO substrates identified in this study were involved in diverse biological processes. Additionally, SUMO substrates identified from different cell cycle stages or pulled down by different SUMO homologs were enriched for distinct cellular components and functional categories. Our results comprehensively profile the sumoylation occurring in the Xenopus egg extract system.
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Affiliation(s)
- Li Ma
- From the ‡Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Aaron Aslanian
- From the ‡Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA; §Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Huaiyu Sun
- From the ‡Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Mingji Jin
- From the ‡Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Yu Shi
- From the ‡Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - John R Yates
- §Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Tony Hunter
- From the ‡Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA;
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18
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Feine O, Hukasova E, Bruinsma W, Freire R, Fainsod A, Gannon J, Mahbubani HM, Lindqvist A, Brandeis M. Phosphorylation-mediated stabilization of Bora in mitosis coordinates Plx1/Plk1 and Cdk1 oscillations. Cell Cycle 2014; 13:1727-36. [PMID: 24675888 PMCID: PMC4111719 DOI: 10.4161/cc.28630] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/23/2014] [Indexed: 11/19/2022] Open
Abstract
Cdk1 and Plk1/Plx1 activation leads to their inactivation through negative feedback loops. Cdk1 deactivates itself by activating the APC/C, consequently generating embryonic cell cycle oscillations. APC/C inhibition by the mitotic checkpoint in somatic cells and the cytostatic factor (CSF) in oocytes sustain the mitotic state. Plk1/Plx1 targets its co-activator Bora for degradation, but it remains unclear how embryonic oscillations in Plx1 activity are generated, and how Plk1/Plx1 activity is sustained during mitosis. We show that Plx1-mediated degradation of Bora in interphase generates oscillations in Plx1 activity and is essential for development. In CSF extracts, phosphorylation of Bora on the Cdk consensus site T52 blocks Bora degradation. Upon fertilization, Calcineurin dephosphorylates T52, triggering Plx1 oscillations. Similarly, we find that GFP-Bora is degraded when Plk1 activity spreads to somatic cell cytoplasm before mitosis. Interestingly, GFP-Bora degradation stops upon mitotic entry when Cdk1 activity is high. We hypothesize that Cdk1 controls Bora through an incoherent feedforward loop synchronizing the activities of mitotic kinases.
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Affiliation(s)
- Oren Feine
- Department of Genetics; The Hebrew University of Jerusalem; Jerusalem, Israel
| | - Elvira Hukasova
- Department of Cell and Molecular Biology; Karolinska Institute; Stockholm, Sweden
| | - Wytse Bruinsma
- Department of Cell Biology; The Netherlands Cancer Institute; Amsterdam, Netherlands
| | - Raimundo Freire
- Unidad de Investigación; Hospital Universitario de Canarias; Instituto de Tecnologias Biomedicas; Tenerife, Spain
| | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research; The Hebrew University of Jerusalem; Jerusalem, Israel
| | - Julian Gannon
- Cancer Research UK; Clare Hall Laboratories; South Mimms, Hertfordshire, UK
| | - Hiro M Mahbubani
- Cancer Research UK; Clare Hall Laboratories; South Mimms, Hertfordshire, UK
| | - Arne Lindqvist
- Department of Cell and Molecular Biology; Karolinska Institute; Stockholm, Sweden
| | - Michael Brandeis
- Department of Genetics; The Hebrew University of Jerusalem; Jerusalem, Israel
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19
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Akopyan K, Silva Cascales H, Hukasova E, Saurin AT, Müllers E, Jaiswal H, Hollman DAA, Kops GJPL, Medema RH, Lindqvist A. Assessing kinetics from fixed cells reveals activation of the mitotic entry network at the S/G2 transition. Mol Cell 2014; 53:843-53. [PMID: 24582498 DOI: 10.1016/j.molcel.2014.01.031] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 12/02/2013] [Accepted: 01/23/2014] [Indexed: 11/24/2022]
Abstract
During the cell cycle, DNA duplication in S phase must occur before a cell divides in mitosis. In the intervening G2 phase, mitotic inducers accumulate, which eventually leads to a switch-like rise in mitotic kinase activity that triggers mitotic entry. However, when and how activation of the signaling network that promotes the transition to mitosis occurs remains unclear. We have developed a system to reduce cell-cell variation and increase accuracy of fluorescence quantification in single cells. This allows us to use immunofluorescence of endogenous marker proteins to assess kinetics from fixed cells. We find that mitotic phosphorylations initially occur at the completion of S phase, showing that activation of the mitotic entry network does not depend on protein accumulation through G2. Our data show insights into how mitotic entry is linked to the completion of S phase and forms a quantitative resource for mathematical models of the human cell cycle.
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Affiliation(s)
- Karen Akopyan
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 171 77 Stockholm, Sweden
| | - Helena Silva Cascales
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 171 77 Stockholm, Sweden
| | - Elvira Hukasova
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 171 77 Stockholm, Sweden
| | - Adrian T Saurin
- Department of Medical Oncology, Department of Molecular Cancer Research, and Cancer Genomics Centre, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands; Division of Cancer Research, Medical Research Institute, University of Dundee, James Arrot Drive, Dundee DD1 9NT, UK
| | - Erik Müllers
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 171 77 Stockholm, Sweden
| | - Himjyot Jaiswal
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 171 77 Stockholm, Sweden
| | - Danielle A A Hollman
- Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Geert J P L Kops
- Department of Medical Oncology, Department of Molecular Cancer Research, and Cancer Genomics Centre, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - René H Medema
- Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands; Division of Cell Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Arne Lindqvist
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 171 77 Stockholm, Sweden; Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands.
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20
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Bruinsma W, Macurek L, Freire R, Lindqvist A, Medema RH. Bora and Aurora-A continue to activate Plk1 in mitosis. J Cell Sci 2014; 127:801-11. [PMID: 24338364 DOI: 10.1242/jcs.137216] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Polo-like kinase-1 (Plk1) is required for proper cell division. Activation of Plk1 requires phosphorylation on a conserved threonine in the T-loop of the kinase domain (T210). Plk1 is first phosphorylated on T210 in G2 phase by the kinase Aurora-A, in concert with its cofactor Bora. However, Bora was shown to be degraded prior to entry into mitosis, and it is currently unclear how Plk1 activity is sustained in mitosis. Here we show that the Bora-Aurora-A complex remains the major activator of Plk1 in mitosis. We show that a small amount of Aurora-A activity is sufficient to phosphorylate and activate Plk1 in mitosis. In addition, a fraction of Bora is retained in mitosis, which is essential for continued Aurora-A-dependent T210 phosphorylation of Plk1. We find that once Plk1 is activated, minimal amounts of the Bora-Aurora-A complex are sufficient to sustain Plk1 activity. Thus, the activation of Plk1 by Aurora-A may function as a bistable switch; highly sensitive to inhibition of Aurora-A in its initial activation, but refractory to fluctuations in Aurora-A activity once Plk1 is fully activated. This provides a cell with robust Plk1 activity once it has committed to mitosis.
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Affiliation(s)
- Wytse Bruinsma
- Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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21
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Kim H, Guo F, Brahma S, Xing Y, Burkard ME. Centralspindlin assembly and 2 phosphorylations on MgcRacGAP by Polo-like kinase 1 initiate Ect2 binding in early cytokinesis. Cell Cycle 2014; 13:2952-61. [PMID: 25486482 PMCID: PMC4614826 DOI: 10.4161/15384101.2014.947201] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 01/08/2023] Open
Abstract
Cytokinesis is the final step of cell division which partitions genetic and cytosolic content into daughter cells. Failed cytokinesis causes polyploidy, genetic instability, and cancer. Kinases use phosphorylation to regulate the timing and location of the cytokinetic furrow. Polo-like kinase 1 (Plk1) is an essential mitotic kinase that triggers cytokinesis by phosphorylating MgcRacGAP to create a docking site for Ect2 at the central spindle. Ect2 binds to MgcRacGAP via its N-terminal BRCT domain (BRCA1 C-terminal), which docks at specific phosphorylated residues. Here we investigate the minimal Plk1-dependent phosphorylation sites required for cytokinesis onset. We demonstrate that phosphorylation of the major MgcRacGAP site, S157, is necessary but not sufficient to bind the Ect2 BRCT domain. Phosphorylation of an additional residue on MgcRacGAP at S164 is also required to elicit efficient binding. Surprisingly, BRCT binding additionally requires MKLP1 and its cognate interacting N-terminal domain of MgcRacGAP. Our findings indicate that central spindle assembly and 2 Plk1-dependent phosphorylations are required to establish efficient binding of the Ect2 BRCT in early cytokinesis. We propose that these requirements establish a high threshold to restrain premature or ectopic cytokinesis.
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Affiliation(s)
- Hyunjung Kim
- Hematology/Oncology Division; Department of Medicine; University of Wisconsin Carbone Cancer Center; Madison, WI USA
| | - Feng Guo
- McArdle Laboratory; Department of Oncology; School of Medicine and Public Health; University of Wisconsin; Madison, WI USA
- Current Affiliation: School of Medicine; Stanford University; Stanford, CA USA
| | - Sarang Brahma
- Hematology/Oncology Division; Department of Medicine; University of Wisconsin Carbone Cancer Center; Madison, WI USA
| | - Yongna Xing
- McArdle Laboratory; Department of Oncology; School of Medicine and Public Health; University of Wisconsin; Madison, WI USA
| | - Mark E Burkard
- Hematology/Oncology Division; Department of Medicine; University of Wisconsin Carbone Cancer Center; Madison, WI USA
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22
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Hégarat N, Vesely C, Vinod PK, Ocasio C, Peter N, Gannon J, Oliver AW, Novák B, Hochegger H. PP2A/B55 and Fcp1 regulate Greatwall and Ensa dephosphorylation during mitotic exit. PLoS Genet 2014; 10:e1004004. [PMID: 24391510 PMCID: PMC3879168 DOI: 10.1371/journal.pgen.1004004] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 10/22/2013] [Indexed: 12/17/2022] Open
Abstract
Entry into mitosis is triggered by activation of Cdk1 and inactivation of its counteracting phosphatase PP2A/B55. Greatwall kinase inactivates PP2A/B55 via its substrates Ensa and ARPP19. Both Greatwall and Ensa/ARPP19 are regulated by phosphorylation, but the dynamic regulation of Greatwall activity and the phosphatases that control Greatwall kinase and its substrates are poorly understood. To address these questions we applied a combination of mathematical modelling and experiments using phospho-specific antibodies to monitor Greatwall, Ensa/ARPP19 and Cdk substrate phosphorylation during mitotic entry and exit. We demonstrate that PP2A/B55 is required for Gwl dephosphorylation at the essential Cdk site Thr194. Ensa/ARPP19 dephosphorylation is mediated by the RNA Polymerase II carboxy terminal domain phosphatase Fcp1. Surprisingly, inhibition or depletion of neither Fcp1 nor PP2A appears to block dephosphorylation of the bulk of mitotic Cdk1 substrates during mitotic exit. Taken together our results suggest a hierarchy of phosphatases coordinating Greatwall, Ensa/ARPP19 and Cdk substrate dephosphorylation during mitotic exit.
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Affiliation(s)
- Nadia Hégarat
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Clare Vesely
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - P. K. Vinod
- Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Cory Ocasio
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Nisha Peter
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Julian Gannon
- Genome Stability, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts, United Kingdom
| | - Antony W. Oliver
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Béla Novák
- Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Helfrid Hochegger
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
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23
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Purification and biochemical analysis of catalytically active human cdc25C dual specificity phosphatase. Biochimie 2013; 95:1450-61. [DOI: 10.1016/j.biochi.2013.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 03/22/2013] [Indexed: 11/18/2022]
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24
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Vagnarelli P, Earnshaw WC. Repo-Man-PP1: a link between chromatin remodelling and nuclear envelope reassembly. Nucleus 2012; 3:138-42. [PMID: 22555598 DOI: 10.4161/nucl.19267] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Coordination of late mitotic events is crucial for the maintenance of genome stability and for the control of gene expression after cell division. Reversible protein phosphorylation regulates this process by de-phosphorylation of mitotic phospho-proteins in a sequential and coordinated manner: this allows an orderly sequence of events to take place during mitotic exit. We have identified Repo-Man/PP1 as a phosphatase complex that regulates temporally and spatially chromatin re-organization and nuclear envelope re-formation during anaphase-telophase.
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Affiliation(s)
- Paola Vagnarelli
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, UK.
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