1
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Xu H, Cai Y, Yang H, Li S, Chen P, Wei Z, Wang F, Wang Z, Zhang Y. PPP2R2A promotes Hu sheep pituitary cell proliferation and gonadotropin secretion associated with prolificacy. Anim Reprod Sci 2024; 265:107457. [PMID: 38677100 DOI: 10.1016/j.anireprosci.2024.107457] [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: 01/02/2024] [Revised: 03/07/2024] [Accepted: 03/12/2024] [Indexed: 04/29/2024]
Abstract
The anterior pituitary plays a critical role in the endocrine system, contains gonadotrophs, which regulate reproductive efficiency by secreting follicle-stimulating hormone (FSH) and luteinizing hormone (LH). PPP2R2A is a serine-threonine phosphatase that regulates reproductive functions in both females and males, its function in pituitary cells remain unclear. Hu sheep is a highly prolific breed, which makes it suitable for studying reproductive mechanisms. In this study, the relative abundances of PPP2R2A mRNA expression were higher in the pituitary of high-prolificacy (HF) Hu sheep compared to those of low-prolificacy (LF) Hu sheep. Additionally, we demonstrated that PPP2R2A promotes pituitary cell proliferation and gonadotropin secretion using the EdU assay and ELISA, respectively. Moreover, it inhibits pituitary cell apoptosis using flow cytometry. Furthermore, PPP2R2A may affect pituitary cell function by regulating the AKT/mTOR signaling pathway. In summary, our findings suggest that PPP2R2A may play a role in regulating pituitary function and influencing the secretion of gonadotropins.
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Affiliation(s)
- Hui Xu
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Yu Cai
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Hua Yang
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Shanglai Li
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Peiyong Chen
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Zongyou Wei
- Taicang Animal husbandry and veterinary station, Taicang 215400, China
| | - Feng Wang
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Ziyu Wang
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yanli Zhang
- Jiangsu Livestock Embryo Engineering Laboratory, Nanjing Agricultural University, Nanjing 210095, China.
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2
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Jin H, Kim J, Lee O, Kim H, No KT. Leveraging the Fragment Molecular Orbital Method to Explore the PLK1 Kinase Binding Site and Polo-Box Domain for Potent Small-Molecule Drug Design. Int J Mol Sci 2023; 24:15639. [PMID: 37958623 PMCID: PMC10650754 DOI: 10.3390/ijms242115639] [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: 09/15/2023] [Revised: 10/19/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
Polo-like kinase 1 (PLK1) plays a pivotal role in cell division regulation and emerges as a promising therapeutic target for cancer treatment. Consequently, the development of small-molecule inhibitors targeting PLK1 has become a focal point in contemporary research. The adenosine triphosphate (ATP)-binding site and the polo-box domain in PLK1 present crucial interaction sites for these inhibitors, aiming to disrupt the protein's function. However, designing potent and selective small-molecule inhibitors can be challenging, requiring a deep understanding of protein-ligand interaction mechanisms at these binding sites. In this context, our study leverages the fragment molecular orbital (FMO) method to explore these site-specific interactions in depth. Using the FMO approach, we used the FMO method to elucidate the molecular mechanisms of small-molecule drugs binding to these sites to design PLK1 inhibitors that are both potent and selective. Our investigation further entailed a comparative analysis of various PLK1 inhibitors, each characterized by distinct structural attributes, helping us gain a better understanding of the relationship between molecular structure and biological activity. The FMO method was particularly effective in identifying key binding features and predicting binding modes for small-molecule ligands. Our research also highlighted specific "hot spot" residues that played a critical role in the selective and robust binding of PLK1. These findings provide valuable insights that can be used to design new and effective PLK1 inhibitors, which can have significant implications for developing anticancer therapeutics.
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Affiliation(s)
- Haiyan Jin
- The Interdisciplinary Graduate Program in Integrative Biotechnology & Translational Medicine, Yonsei University, Incheon 21983, Republic of Korea; (H.J.); (O.L.)
| | - Jongwan Kim
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
- Bioinformatics and Molecular Design Research Center (BMDRC), Incheon 21983, Republic of Korea;
| | - Onju Lee
- The Interdisciplinary Graduate Program in Integrative Biotechnology & Translational Medicine, Yonsei University, Incheon 21983, Republic of Korea; (H.J.); (O.L.)
| | - Hyein Kim
- Bioinformatics and Molecular Design Research Center (BMDRC), Incheon 21983, Republic of Korea;
| | - Kyoung Tai No
- The Interdisciplinary Graduate Program in Integrative Biotechnology & Translational Medicine, Yonsei University, Incheon 21983, Republic of Korea; (H.J.); (O.L.)
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
- Bioinformatics and Molecular Design Research Center (BMDRC), Incheon 21983, Republic of Korea;
- Baobab AiBIO Co., Ltd., Incheon 21983, Republic of Korea
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3
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Zhang J, Zhang L, Wang J, Ouyang L, Wang Y. Polo-like Kinase 1 Inhibitors in Human Cancer Therapy: Development and Therapeutic Potential. J Med Chem 2022; 65:10133-10160. [PMID: 35878418 DOI: 10.1021/acs.jmedchem.2c00614] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Polo-like kinase 1 (PLK1) plays an important role in a variety of cellular functions, including the regulation of mitosis, DNA replication, autophagy, and the epithelial-mesenchymal transition (EMT). PLK1 overexpression is often associated with cell proliferation and poor prognosis in cancer patients, making it a promising antitumor target. To date, at least 10 PLK1 inhibitors (PLK1i) have been entered into clinical trials, among which the typical kinase domain (KD) inhibitor BI 6727 (volasertib) was granted "breakthrough therapy designation" by the FDA in 2013. Unfortunately, many other KD inhibitors showed poor specificity, resulting in dose-limiting toxicity, which has greatly impeded their development. Researchers recently discovered many PLK1i with higher selectivity, stronger potency, and better absorption, distribution, metabolism, and elimination (ADME) characteristics. In this review, we emphasize the structure-activity relationships (SARs) of PLK1i, providing insights into new drugs targeting PLK1 for antitumor clinical practice.
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Affiliation(s)
- Jifa Zhang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Lele Zhang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Jiaxing Wang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis 38163, Tennessee, United States
| | - Liang Ouyang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yuxi Wang
- Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, Joint Research Institution of Altitude Health, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
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4
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Ferrari R, Cong G, Chattopadhyay A, Xie B, Assaf E, Morder K, Calderon MJ, Watkins SC, Sachdev U. Attenuated cell-cycle division protein 2 and elevated mitotic roles of polo-like kinase 1 characterize deficient myoblast fusion in peripheral arterial disease. Biochem Biophys Res Commun 2022; 609:163-168. [PMID: 35436627 PMCID: PMC10687717 DOI: 10.1016/j.bbrc.2022.03.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/26/2022] [Accepted: 03/31/2022] [Indexed: 11/02/2022]
Abstract
INTRODUCTION We propose that MuSC-derived myoblasts in PAD have transcriptomic differences that can highlight underlying causes of ischemia-induced myopathy. METHODS Differentiation capacity among perfused and ischemic human myoblasts was compared. Following next generation sequencing of mRNA, Ingenuity Pathway Analysis (IPA) was performed for canonical pathway enrichment. Live cell imaging and immunofluorescence were performed to determine myocyte fusion index and protein expression based on insights from IPA, specifically concerning cell cycle regulators including cell-division cycle protein 2 (CDC2) and polo-like kinase 1 (PLK1). RESULTS Ischemic myoblasts formed attenuated myotubes indicative of reduced fusion. Additionally, myoblasts from ischemic segments showed significant differences in canonical pathways associated with PLK1 (upregulated) and G2/M DNA damage checkpoint regulation (downregulated). PLK1 inhibition with BI2536 did not affect cell viability in any group over 24 h but deterred fusion more significantly in PAD myoblasts. Furthermore, PLK1 inhibition reduced the expression of checkpoint protein CDC2 in perfused but not ischemic cells. CONCLUSION Differentiating myoblasts derived from ischemic muscle have significant differences in gene expression including those essential to DNA-damage checkpoint regulation and cell cycle progress. DNA-damage checkpoint dysregulation may contribute to myopathy in PAD.
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Affiliation(s)
- Ricardo Ferrari
- University of Pittsburgh Medical Center Department of Surgery, Division of Vascular Surgery, USA
| | - Guangzhi Cong
- University of Pittsburgh Medical Center Department of Surgery, Division of Vascular Surgery, USA; Department of Cardiology, Cardiovascular Institute, General Hospital of Ningxia Medical University, Yinchuan, Ningxia, China
| | | | - B Xie
- University of Pittsburgh Medical Center Department of Surgery, Division of Vascular Surgery, USA
| | - E Assaf
- University of Pittsburgh Medical Center Department of Surgery, Division of Vascular Surgery, USA
| | - K Morder
- University of Pittsburgh Medical Center Department of Surgery, Division of Vascular Surgery, USA
| | | | | | - Ulka Sachdev
- University of Pittsburgh Medical Center Department of Surgery, Division of Vascular Surgery, USA.
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5
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Fernando M, Duijf PHG, Proctor M, Stevenson AJ, Ehmann A, Vora S, Skalamera D, Adams M, Gabrielli B. Dysregulated G2 phase checkpoint recovery pathway reduces DNA repair efficiency and increases chromosomal instability in a wide range of tumours. Oncogenesis 2021; 10:41. [PMID: 33993200 PMCID: PMC8124070 DOI: 10.1038/s41389-021-00329-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/06/2021] [Accepted: 04/20/2021] [Indexed: 11/12/2022] Open
Abstract
Defective DNA repair is being demonstrated to be a useful target in cancer treatment. Currently, defective repair is identified by specific gene mutations, however defective repair is a common feature of cancers without these mutations. DNA damage triggers cell cycle checkpoints that are responsible for co-ordinating cell cycle arrest and DNA repair. Defects in checkpoint signalling components such as ataxia telangiectasia mutated (ATM) occur in a low proportion of cancers and are responsible for reduced DNA repair and increased genomic instability. Here we have investigated the AURKA-PLK1 cell cycle checkpoint recovery pathway that is responsible for exit from the G2 phase cell cycle checkpoint arrest. We demonstrate that dysregulation of PP6 and AURKA maintained elevated PLK1 activation to promote premature exit from only ATM, and not ATR-dependent checkpoint arrest. Surprisingly, depletion of the B55α subunit of PP2A that negatively regulates PLK1 was capable of overcoming ATM and ATR checkpoint arrests. Dysregulation of the checkpoint recovery pathway reduced S/G2 phase DNA repair efficiency and increased genomic instability. We found a strong correlation between dysregulation of the PP6-AURKA-PLK1-B55α checkpoint recovery pathway with signatures of defective homologous recombination and increased chromosomal instability in several cancer types. This work has identified an unrealised source of G2 phase DNA repair defects and chromosomal instability that are likely to be sensitive to treatments targeting defective repair.
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Affiliation(s)
- Madushan Fernando
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Pascal H G Duijf
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Faculty of Health, School of Biomedical Sciences, Brisbane, QLD, Australia.,Centre for Data Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD, Australia
| | - Martina Proctor
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | | | - Anna Ehmann
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Shivam Vora
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Dubravka Skalamera
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Mark Adams
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Faculty of Health, School of Biomedical Sciences, Brisbane, QLD, Australia
| | - Brian Gabrielli
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia.
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6
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Cordeiro MH, Smith RJ, Saurin AT. Kinetochore phosphatases suppress autonomous Polo-like kinase 1 activity to control the mitotic checkpoint. J Cell Biol 2020; 219:e202002020. [PMID: 33125045 PMCID: PMC7608062 DOI: 10.1083/jcb.202002020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 08/20/2020] [Accepted: 10/12/2020] [Indexed: 01/04/2023] Open
Abstract
Local phosphatase regulation is needed at kinetochores to silence the mitotic checkpoint (a.k.a. spindle assembly checkpoint [SAC]). A key event in this regard is the dephosphorylation of MELT repeats on KNL1, which removes SAC proteins from the kinetochore, including the BUB complex. We show here that PP1 and PP2A-B56 phosphatases are primarily required to remove Polo-like kinase 1 (PLK1) from the BUB complex, which can otherwise maintain MELT phosphorylation in an autocatalytic manner. This appears to be their principal role in the SAC because both phosphatases become redundant if PLK1 is inhibited or BUB-PLK1 interaction is prevented. Surprisingly, MELT dephosphorylation can occur normally under these conditions even when the levels or activities of PP1 and PP2A are strongly inhibited at kinetochores. Therefore, these data imply that kinetochore phosphatase regulation is critical for the SAC, but primarily to restrain and extinguish autonomous PLK1 activity. This is likely a conserved feature of the metazoan SAC, since the relevant PLK1 and PP2A-B56 binding motifs have coevolved in the same region on MADBUB homologues.
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Affiliation(s)
| | | | - Adrian T. Saurin
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, UK
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7
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Ciardo D, Haccard O, Narassimprakash H, Chiodelli V, Goldar A, Marheineke K. Polo-like kinase 1 (Plk1) is a positive regulator of DNA replication in the Xenopus in vitro system. Cell Cycle 2020; 19:1817-1832. [PMID: 32573322 PMCID: PMC7469467 DOI: 10.1080/15384101.2020.1782589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/24/2020] [Accepted: 06/07/2020] [Indexed: 12/18/2022] Open
Abstract
Polo-like kinase 1 (Plk1) is a cell cycle kinase essential for mitosis progression, but also important for checkpoint recovery and adaptation in response to DNA damage and replication stress. However, although Plk1 is expressed in S phase, little is known about its function during unperturbed DNA replication. Using Xenopus laevis egg extracts, mimicking early embryonic replication, we demonstrate that Plk1 is simultaneously recruited to chromatin with pre-replication proteins where it accumulates throughout S phase. Further, we found that chromatin-bound Plk1 is phosphorylated on its activating site T201, which appears to be sensitive to dephosphorylation by protein phosphatase 2A. Extracts immunodepleted of Plk1 showed a decrease in DNA replication, rescued by wild type recombinant Plk1. Inversely, modest Plk1 overexpression accelerated DNA replication. Plk1 depletion led to an increase in Chk1 phosphorylation and to a decrease in Cdk2 activity, which strongly suggests that Plk1 could inhibit the ATR/Chk1-dependent intra-S phase checkpoint during normal S phase. In addition, we observed that phosphorylated Plk1 levels are high during the rapid, early cell cycles of Xenopus development but decrease after the mid-blastula transition when the cell cycle and the replication program slow down along with more active checkpoints. These data shed new light on the role of Plk1 as a positive regulating factor for DNA replication in early, rapidly dividing embryos.
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Affiliation(s)
- Diletta Ciardo
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Olivier Haccard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Hemalatha Narassimprakash
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Virginie Chiodelli
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Arach Goldar
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Kathrin Marheineke
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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8
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Panicker N, Coutman M, Lawlor-O'Neill C, Kahl RGS, Roselli S, Verrills NM. Ppp2r2a Knockout Mice Reveal That Protein Phosphatase 2A Regulatory Subunit, PP2A-B55α, Is an Essential Regulator of Neuronal and Epidermal Embryonic Development. Front Cell Dev Biol 2020; 8:358. [PMID: 32582689 PMCID: PMC7290052 DOI: 10.3389/fcell.2020.00358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/22/2020] [Indexed: 12/13/2022] Open
Abstract
The serine/threonine protein phosphatase 2A (PP2A) is a master regulator of the complex cellular signaling that occurs during all stages of mammalian development. PP2A is composed of a catalytic, a structural, and regulatory subunit, for which there are multiple isoforms. The association of specific regulatory subunits determines substrate specificity and localization of phosphatase activity, however, the precise role of each regulatory subunit in development is not known. Here we report the generation of the first knockout mouse for the Ppp2r2a gene, encoding the PP2A-B55α regulatory subunit, using CRISPR/Cas9. Heterozygous animals developed and grew as normal, however, homozygous knockout mice were not viable. Analysis of embryos at different developmental stages found a normal Mendelian ratio of Ppp2r2a–/– embryos at embryonic day (E) 10.5 (25%), but reduced Ppp2r2a–/– embryos at E14.5 (18%), and further reduced at E18.5 (10%). No live Ppp2r2a–/– pups were observed at birth. Ppp2r2a–/– embryos were significantly smaller than wild-type or heterozygous littermates and displayed a variety of neural defects such as exencephaly, spina bifida, and cranial vault collapse, as well as syndactyly and severe epidermal defects; all processes driven by growth and differentiation of the ectoderm. Ppp2r2a–/– embryos had incomplete epidermal barrier acquisition, associated with thin, poorly differentiated stratified epithelium with weak attachment to the underlying dermis. The basal keratinocytes in Ppp2r2a–/– embryos were highly disorganized, with reduced immunolabeling of integrins and basement membrane proteins, suggesting impaired focal adhesion and hemidesmosome assembly. The spinous and granular layers were thinner in the Ppp2r2a–/– embryos, with aberrant expression of adherens and tight junction associated proteins. The overlying stratum corneum was either absent or incomplete. Thus PP2A-B55α is an essential regulator of epidermal stratification, and is essential for ectodermal development during embryogenesis.
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Affiliation(s)
- Nikita Panicker
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia.,Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Melody Coutman
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia.,Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Charley Lawlor-O'Neill
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia.,Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Richard G S Kahl
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia.,Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Séverine Roselli
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia.,Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia.,Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
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9
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Cell Cycle and DNA Repair Regulation in the Damage Response: Protein Phosphatases Take Over the Reins. Int J Mol Sci 2020; 21:ijms21020446. [PMID: 31936707 PMCID: PMC7014277 DOI: 10.3390/ijms21020446] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.
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10
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Pavey S, Pinder A, Fernando W, D'Arcy N, Matigian N, Skalamera D, Lê Cao KA, Loo-Oey D, Hill MM, Stark M, Kimlin M, Burgess A, Cloonan N, Sturm RA, Gabrielli B. Multiple interaction nodes define the postreplication repair response to UV-induced DNA damage that is defective in melanomas and correlated with UV signature mutation load. Mol Oncol 2019; 14:22-41. [PMID: 31733171 PMCID: PMC6944116 DOI: 10.1002/1878-0261.12601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/06/2019] [Accepted: 11/14/2019] [Indexed: 01/25/2023] Open
Abstract
Ultraviolet radiation‐induced DNA mutations are a primary environmental driver of melanoma. The reason for this very high level of unrepaired DNA lesions leading to these mutations is still poorly understood. The primary DNA repair mechanism for UV‐induced lesions, that is, the nucleotide excision repair pathway, appears intact in most melanomas. We have previously reported a postreplication repair mechanism that is commonly defective in melanoma cell lines. Here we have used a genome‐wide approach to identify the components of this postreplication repair mechanism. We have used differential transcript polysome loading to identify transcripts that are associated with UV response, and then functionally assessed these to identify novel components of this repair and cell cycle checkpoint network. We have identified multiple interaction nodes, including global genomic nucleotide excision repair and homologous recombination repair, and previously unexpected MASTL pathway, as components of the response. Finally, we have used bioinformatics to assess the contribution of dysregulated expression of these pathways to the UV signature mutation load of a large melanoma cohort. We show that dysregulation of the pathway, especially the DNA damage repair components, are significant contributors to UV mutation load, and that dysregulation of the MASTL pathway appears to be a significant contributor to high UV signature mutation load.
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Affiliation(s)
- Sandra Pavey
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Alex Pinder
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Winnie Fernando
- Mater Research, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Nicholas D'Arcy
- Mater Research, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Nicholas Matigian
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia.,QFAB Bioinformatics, The University of Queensland, Brisbane, QLD, Australia
| | - Dubravka Skalamera
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia.,Mater Research, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Kim-Anh Lê Cao
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Dorothy Loo-Oey
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Michelle M Hill
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia.,QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Mitchell Stark
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Michael Kimlin
- University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | | | - Nicole Cloonan
- QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Richard A Sturm
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia
| | - Brian Gabrielli
- Diamantina Institute, TRI, The University of Queensland, Woolloongabba, QLD, Australia.,Mater Research, TRI, The University of Queensland, Woolloongabba, QLD, Australia
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11
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Magescas J, Zonka JC, Feldman JL. A two-step mechanism for the inactivation of microtubule organizing center function at the centrosome. eLife 2019; 8:47867. [PMID: 31246171 PMCID: PMC6684319 DOI: 10.7554/elife.47867] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/26/2019] [Indexed: 01/18/2023] Open
Abstract
The centrosome acts as a microtubule organizing center (MTOC), orchestrating microtubules into the mitotic spindle through its pericentriolar material (PCM). This activity is biphasic, cycling through assembly and disassembly during the cell cycle. Although hyperactive centrosomal MTOC activity is a hallmark of some cancers, little is known about how the centrosome is inactivated as an MTOC. Analysis of endogenous PCM proteins in C. elegans revealed that the PCM is composed of partially overlapping territories organized into an inner and outer sphere that are removed from the centrosome at different rates and using different behaviors. We found that phosphatases oppose the addition of PCM by mitotic kinases, ultimately catalyzing the dissolution of inner sphere PCM proteins at the end of mitosis. The nature of the PCM appears to change such that the remaining aging PCM outer sphere is mechanically ruptured by cortical pulling forces, ultimately inactivating MTOC function at the centrosome. New cells are created when existing cells divide, a process that is critical for life. A structure called the spindle is an important part of cell division, helping to orient the division and separate parts of the old cell into the newly generated ones. The spindle is built using filamentous protein structures called microtubules which are arranged by microtubule organizing centers (or MTOCs for short). In animals, an MTOC forms at each end of the spindle around two structures called centrosomes. A network of proteins called the pericentriolar material (PCM) form around centrosomes, converting them into MTOCs. The PCM grows around centrosomes as a cell prepares to divide and is removed again afterward. Enzymes called kinases are important in controlling cell division and PCM assembly; they are opposed by other enzymes known as phosphatases. The processes involved in organization and removal of the PCM are not well understood. The microscopic worm Caenorhabditis elegans provides an opportunity to study details of cell division in a living animal. Magescas et al. used fluorescent labels to view proteins from the PCM under a microscope. The images showed two partially overlapping spherical parts to the PCM – inner and outer. Further examination revealed that the inner PCM is maintained by a careful balance of kinase and phosphatase activity. When kinases shut down at the end of cell division, the phosphatases break down the inner PCM. By contrast, the outer PCM is physically torn apart by forces acting through the attached microtubules. Future work will seek to examine which proteins are specifically affected by phosphatases to identify the key regulators of PCM persistence in the cell and to reveal the proteins needed for MTOC activity at the centrosome. Since poor MTOC regulation can play a part in the growth and spread of cancer, this could lead to targets for new treatments.
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Affiliation(s)
- Jérémy Magescas
- Department of Biology, Stanford University, Stanford, United States
| | - Jenny C Zonka
- Department of Biology, Stanford University, Stanford, United States
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12
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Ramos F, Villoria MT, Alonso-Rodríguez E, Clemente-Blanco A. Role of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DNA damage response. Cell Stress 2019; 3:70-85. [PMID: 31225502 PMCID: PMC6551743 DOI: 10.15698/cst2019.03.178] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Maintenance of genome integrity is fundamental for cellular physiology. Our hereditary information encoded in the DNA is intrinsically susceptible to suffer variations, mostly due to the constant presence of endogenous and environmental genotoxic stresses. Genomic insults must be repaired to avoid loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental anomalies and tumorigenesis. To safeguard our genome, cells have evolved a series of mechanisms collectively known as the DNA damage response (DDR). This surveillance system regulates multiple features of the cellular response, including the detection of the lesion, a transient cell cycle arrest and the restoration of the broken DNA molecule. While the role of multiple kinases in the DDR has been well documented over the last years, the intricate roles of protein dephosphorylation have only recently begun to be addressed. In this review, we have compiled recent information about the function of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DDR, focusing mainly on their capacity to regulate the DNA damage checkpoint and the repair mechanism encompassed in the restoration of a DNA lesion.
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Affiliation(s)
- Facundo Ramos
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - María Teresa Villoria
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Esmeralda Alonso-Rodríguez
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
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13
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Raman D, Pervaiz S. Redox inhibition of protein phosphatase PP2A: Potential implications in oncogenesis and its progression. Redox Biol 2019; 27:101105. [PMID: 30686777 PMCID: PMC6859563 DOI: 10.1016/j.redox.2019.101105] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 01/17/2023] Open
Abstract
Cellular processes are dictated by the active signaling of proteins relaying messages to regulate cell proliferation, apoptosis, signal transduction and cell communications. An intricate web of protein kinases and phosphatases are critical to the proper transmission of signals across such cascades. By governing 30–50% of all protein dephosphorylation in the cell, with prominent substrate proteins being key regulators of signaling cascades, the phosphatase PP2A has emerged as a celebrated player in various developmental and tumorigenic pathways, thereby posing as an attractive target for therapeutic intervention in various pathologies wherein its activity is deregulated. This review is mainly focused on refreshing our understanding of the structural and functional complexity that cocoons the PP2A phosphatase, and its expression in cancers. Additionally, we focus on its physiological regulation as well as into recent advents and strategies that have shown promise in countering the deregulation of the phosphatase through its targeted reactivation. Finally, we dwell upon one of the key regulators of PP2A in cancer cells-cellular redox status-its multifarious nature, and its integration into the reactome of PP2A, highlighting some of the significant impacts that ROS can inflict on the structural modifications and functional aspect of PP2A.
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Affiliation(s)
- Deepika Raman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shazib Pervaiz
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Medical Science Cluster Cancer Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; National University Cancer Institute, National University Health System, Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
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14
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Marzec K, Burgess A. The Oncogenic Functions of MASTL Kinase. Front Cell Dev Biol 2018; 6:162. [PMID: 30555827 PMCID: PMC6282046 DOI: 10.3389/fcell.2018.00162] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/08/2018] [Indexed: 01/14/2023] Open
Abstract
MASTL kinase is a master regulator of mitosis, essential for ensuring that mitotic substrate phosphorylation is correctly maintained. It achieves this through the phosphorylation of alpha-endosulfine and subsequent inhibition of the tumor suppressor PP2A-B55 phosphatase. In recent years MASTL has also emerged as a novel oncogenic kinase that is upregulated in a number of cancer types, correlating with chromosome instability and poor patient survival. While the chromosome instability is likely directly linked to MASTL's control of mitotic phosphorylation, several new studies indicated that MASTL has additional effects outside of mitosis and beyond regulation of PP2A-B55. These include control of normal DNA replication timing, and regulation of AKT/mTOR and Wnt/β-catenin oncogenic kinase signaling. In this review, we will examine the phenotypes and mechanisms for how MASTL, ENSA, and PP2A-B55 deregulation drives tumor progression and metastasis. Finally, we will explore the rationale for the future development of MASTL inhibitors as new cancer therapeutics.
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Affiliation(s)
- Kamila Marzec
- ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia
| | - Andrew Burgess
- ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health, Concord Clinical School, University of Sydney, Sydney, NSW, Australia
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15
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Abstract
Double-stranded DNA breaks activate a DNA damage checkpoint in G2 phase to trigger a cell cycle arrest, which can be reversed to allow for recovery. However, damaged G2 cells can also permanently exit the cell cycle, going into senescence or apoptosis, raising the question how an individual cell decides whether to recover or withdraw from the cell cycle. Here we find that the decision to withdraw from the cell cycle in G2 is critically dependent on the progression of DNA repair. We show that delayed processing of double strand breaks through HR-mediated repair results in high levels of resected DNA and enhanced ATR-dependent signalling, allowing p21 to rise to levels at which it drives cell cycle exit. These data imply that cells have the capacity to discriminate breaks that can be repaired from breaks that are difficult to repair at a time when repair is still ongoing. Cells with damaged DNA can permanently exit the cell cycle during the G2 phase or recover spontaneously entering mitosis. Here the authors reveal that the decision to exit from the cell cycle in G2 is dependent on the presence of repair intermediates associated with homologous recombination.
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16
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Rubio A, García-Blanco N, Vázquez-Bolado A, Belén Suárez M, Moreno S. Nutritional cell cycle reprogramming reveals that inhibition of Cdk1 is required for proper MBF-dependent transcription. J Cell Sci 2018; 131:jcs.218743. [PMID: 30154212 DOI: 10.1242/jcs.218743] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/20/2018] [Indexed: 01/22/2023] Open
Abstract
In nature, cells and in particular unicellular microorganisms are exposed to a variety of nutritional environments. Fission yeast cells cultured in nitrogen-rich media grow fast, divide with a large size and show a short G1 and a long G2. However, when cultured in nitrogen-poor media, they exhibit reduced growth rate and cell size and a long G1 and a short G2. In this study, we compared the phenotypes of cells lacking the highly conserved cyclin-dependent kinase (Cdk) inhibitor Rum1 and the anaphase-promoting complex/cyclosome (APC/C) activator Ste9 in nitrogen-rich and nitrogen-poor media. Rum1 and Ste9 are dispensable for cell division in nitrogen-rich medium. However, in nitrogen-poor medium they are essential for generating a proper wave of MluI cell-cycle box binding factor (MBF)-dependent transcription at the end of G1, which is crucial for promoting a successful S phase. Mutants lacking Rum1 and Ste9 showed premature entry into S phase and a reduced wave of MBF-dependent transcription, leading to replication stress, DNA damage and G2 cell cycle arrest. This work demonstrates how reprogramming the cell cycle by changing the nutritional environment may reveal new roles for cell cycle regulators.
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Affiliation(s)
- Angela Rubio
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - Natalia García-Blanco
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - Alicia Vázquez-Bolado
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - María Belén Suárez
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - Sergio Moreno
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain
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17
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Abstract
Mitosis is controlled by reversible protein phosphorylation involving specific kinases and phosphatases. A handful of major mitotic protein kinases, such as the cyclin B-CDK1 complex, the Aurora kinases, and Polo-like kinase 1 (PLK1), cooperatively regulate distinct mitotic processes. Research has identified proteins and mechanisms that integrate these kinases into signaling cascades that guide essential mitotic events. These findings have important implications for our understanding of the mechanisms of mitotic regulation and may advance the development of novel antimitotic drugs. We review collected evidence that in vertebrates, the Aurora kinases serve as catalytic subunits of distinct complexes formed with the four scaffold proteins Bora, CEP192, INCENP, and TPX2, which we deem "core" Aurora cofactors. These complexes and the Aurora-PLK1 cascades organized by Bora, CEP192, and INCENP control crucial aspects of mitosis and all pathways of spindle assembly. We compare the mechanisms of Aurora activation in relation to the different spindle assembly pathways and draw a functional analogy between the CEP192 complex and the chromosomal passenger complex that may reflect the coevolution of centrosomes, kinetochores, and the actomyosin cleavage apparatus. We also analyze the roles and mechanisms of Aurora-PLK1 signaling in the cell and centrosome cycles and in the DNA damage response.
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Affiliation(s)
- Vladimir Joukov
- N.N. Petrov National Medical Research Center of Oncology, Saint-Petersburg 197758, Russian Federation.
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18
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Pintard L, Archambault V. A unified view of spatio-temporal control of mitotic entry: Polo kinase as the key. Open Biol 2018; 8:180114. [PMID: 30135239 PMCID: PMC6119860 DOI: 10.1098/rsob.180114] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 07/29/2018] [Indexed: 12/18/2022] Open
Abstract
The Polo kinase is an essential regulator of cell division. Its ability to regulate multiple events at distinct subcellular locations and times during mitosis is remarkable. In the last few years, a much clearer mechanistic understanding of the functions and regulation of Polo in cell division has emerged. In this regard, the importance of coupling changes in activity with changes in localization is striking, both for Polo itself and for its upstream regulators. This review brings together several new pieces of the puzzle that are gradually revealing how Polo is regulated, in space and time, to enable its functions in the early stages of mitosis in animal cells. As a result, a unified view of how mitotic entry is spatio-temporally regulated is emerging.
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Affiliation(s)
- Lionel Pintard
- Cell Cycle and Development Team, Institut Jacques Monod, UMR7592 CNRS-Université Paris Diderot, Sorbonne Paris Cité, Ligue contre le Cancer, Paris, France
- Equipe labellisée, Ligue contre le Cancer, Paris, France
| | - Vincent Archambault
- Institut de recherche en immunologie et en cancérologie, Université de Montréal, Montréal, Québec, Canada
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19
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Vigneron S, Sundermann L, Labbé JC, Pintard L, Radulescu O, Castro A, Lorca T. Cyclin A-cdk1-Dependent Phosphorylation of Bora Is the Triggering Factor Promoting Mitotic Entry. Dev Cell 2018; 45:637-650.e7. [PMID: 29870721 DOI: 10.1016/j.devcel.2018.05.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/04/2018] [Accepted: 05/02/2018] [Indexed: 10/14/2022]
Abstract
Mitosis is induced by the activation of the cyclin B/cdk1 feedback loop that creates a bistable state. The triggering factor promoting active cyclin B/cdk1 switch has been assigned to cyclin B/cdk1 accumulation during G2. However, this complex is rapidly inactivated by Wee1/Myt1-dependent phosphorylation of cdk1 making unlikely a triggering role of this kinase in mitotic commitment. Here we show that cyclin A/cdk1 kinase is the factor triggering mitosis. Cyclin A/cdk1 phosphorylates Bora to promote Aurora A-dependent Plk1 phosphorylation and activation and mitotic entry. We demonstrate that Bora phosphorylation by cyclin A/cdk1 is both necessary and sufficient for mitotic commitment. Finally, we identify a site in Bora whose phosphorylation by cyclin A/cdk1 is required for mitotic entry. We constructed a mathematical model confirming the essential role of this kinase in mitotic commitment. Overall, our results uncover the molecular mechanism by which cyclin A/cdk1 triggers mitotic entry.
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Affiliation(s)
- Suzanne Vigneron
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Université de Montpellier, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Lena Sundermann
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Université de Montpellier, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Jean-Claude Labbé
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Université de Montpellier, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Lionel Pintard
- Equipe Labelisée Ligue Contre le Cancer, Institut Jacques Monod, UMR7592, Université Paris-Diderot, Sorbonne Paris Cité, CNRS, Paris, France
| | - Ovidiu Radulescu
- Dynamique des Interactions Membranaires Normales et Pathologiques (DIMNP), CNRS UMR5235, Université de Montpellier, Place E Bataillon, 34095 Montpellier, France
| | - Anna Castro
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Université de Montpellier, 1919 Route de Mende, 34293 Montpellier Cedex 5, France.
| | - Thierry Lorca
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Université de Montpellier, 1919 Route de Mende, 34293 Montpellier Cedex 5, France.
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20
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Severance AL, Latham KE. Meeting the meiotic challenge: Specializations in mammalian oocyte spindle formation. Mol Reprod Dev 2018; 85:178-187. [PMID: 29411912 DOI: 10.1002/mrd.22967] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/03/2018] [Accepted: 02/05/2018] [Indexed: 01/02/2023]
Abstract
Oocytes uniquely accumulate cytoplasmic constituents to support early embryogenesis. This unique specialization is accompanied by acquisition of a large size and by execution of asymmetric meiotic divisions that preserve precious ooplasm through the expulsion of minimal size polar bodies. While often taken for granted, these basic features of oogenesis necessitate unique specializations of the meiotic apparatus. These include a chromatin-sourced RanGTP gradient that restricts spindle size by defining a spatial domain where meiotic spindles form, acentriolar centrosomes that rely on microtubule organizing centers to form spindle poles, and an actin-based mechanism for asymmetric spindle positioning. Additionally, localized protein synthesis to support spindle formation is achieved in the spindle forming region, whilst protein synthesis is reduced elsewhere in the ooplasm. This is achieved through enrichment of spindle-related mRNAs in the spindle forming region combined with local PLK1-mediated phosphorylation and inactivation of the translational repressor EIF4EBP1. This allows PLK1 to function as an important regulatory nexus through which endogenous and exogenous signals can impact spindle formation and function, and highlights the important role that PLK1 may have in maintaining oocyte quality and fertility.
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Affiliation(s)
- Ashley L Severance
- Genetics Graduate Program, East Lansing, Michigan.,Reproductive and Developmental Sciences Program, East Lansing, Michigan
| | - Keith E Latham
- Reproductive and Developmental Sciences Program, East Lansing, Michigan.,Department of Animal Science, Michigan State University, East Lansing, Michigan.,Department of Obstetrics, Gynecology and Reproductive Biology, East Lansing, Michigan
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21
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Liang S, Guo J, Choi JW, Shin KT, Wang HY, Jo YJ, Kim NH, Cui XS. Protein phosphatase 2A regulatory subunit B55α functions in mouse oocyte maturation and early embryonic development. Oncotarget 2018; 8:26979-26991. [PMID: 28439046 PMCID: PMC5432312 DOI: 10.18632/oncotarget.15927] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/17/2017] [Indexed: 12/20/2022] Open
Abstract
Protein phosphatase 2A regulatory subunit B55α (PP2A-B55α) has been studied in mitosis. However, its functions in mammalian meiosis and early embryonic development remain unknown. Here, we report that PP2A-B55α is critical for mouse oocyte meiosis and preimplantation embryo development. Knockdown of PP2A-B55α in oocytes led to abnormal asymmetric division, disordered spindle dynamics, defects in chromosome congression, an increase in aneuploidy, and induction of the DNA damage response. Moreover, knockdown of PP2A-B55α in fertilized mouse zygotes impaired development to the blastocyst stage. The impairment of embryonic development might have been due to induction of sustained DNA damage in embryos, which caused apoptosis and inhibited cell proliferation and outgrowth potential at the blastocyst stage. Overall, these results provide a novel insight into the role of PP2A-B55α as a novel meiotic and embryonic competence factor at the onset of life.
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Affiliation(s)
- Shuang Liang
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Jing Guo
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Jeong-Woo Choi
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Kyung-Tae Shin
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Hai-Yang Wang
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Yu-Jin Jo
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Nam-Hyung Kim
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Xiang-Shun Cui
- Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
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22
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Protein interactomes of protein phosphatase 2A B55 regulatory subunits reveal B55-mediated regulation of replication protein A under replication stress. Sci Rep 2018; 8:2683. [PMID: 29422626 PMCID: PMC5805732 DOI: 10.1038/s41598-018-21040-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/24/2018] [Indexed: 11/24/2022] Open
Abstract
The specific function of PP2A, a major serine/threonine phosphatase, is mediated by regulatory targeting subunits, such as members of the B55 family. Although implicated in cell division and other pathways, the specific substrates and functions of B55 targeting subunits are largely undefined. In this study we identified over 100 binding proteins of B55α and B55β in Xenopus egg extracts that are involved in metabolism, mitochondria function, molecular trafficking, cell division, cytoskeleton, DNA replication, DNA repair, and cell signaling. Among the B55α and B55β-associated proteins were numerous mitotic regulators, including many substrates of CDK1. Consistently, upregulation of B55α accelerated M-phase exit and inhibited M-phase entry. Moreover, specific substrates of CDK2, including factors of DNA replication and chromatin remodeling were identified within the interactomes of B55α and B55β, suggesting a role for these phosphatase subunits in DNA replication. In particular, we confirmed in human cells that B55α binds RPA and mediates the dephosphorylation of RPA2. The B55-RPA association is disrupted after replication stress, consistent with the induction of RPA2 phosphorylation. Thus, we report here a new mechanism that accounts for both how RPA phosphorylation is modulated by PP2A and how the phosphorylation of RPA2 is abruptly induced after replication stress.
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23
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Jaiswal H, Benada J, Müllers E, Akopyan K, Burdova K, Koolmeister T, Helleday T, Medema RH, Macurek L, Lindqvist A. ATM/Wip1 activities at chromatin control Plk1 re-activation to determine G2 checkpoint duration. EMBO J 2017; 36:2161-2176. [PMID: 28607002 PMCID: PMC5510006 DOI: 10.15252/embj.201696082] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 04/05/2017] [Accepted: 05/08/2017] [Indexed: 12/17/2022] Open
Abstract
After DNA damage, the cell cycle is arrested to avoid propagation of mutations. Arrest in G2 phase is initiated by ATM-/ATR-dependent signaling that inhibits mitosis-promoting kinases such as Plk1. At the same time, Plk1 can counteract ATR-dependent signaling and is required for eventual resumption of the cell cycle. However, what determines when Plk1 activity can resume remains unclear. Here, we use FRET-based reporters to show that a global spread of ATM activity on chromatin and phosphorylation of ATM targets including KAP1 control Plk1 re-activation. These phosphorylations are rapidly counteracted by the chromatin-bound phosphatase Wip1, allowing cell cycle restart despite persistent ATM activity present at DNA lesions. Combining experimental data and mathematical modeling, we propose a model for how the minimal duration of cell cycle arrest is controlled. Our model shows how cell cycle restart can occur before completion of DNA repair and suggests a mechanism for checkpoint adaptation in human cells.
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Affiliation(s)
- Himjyot Jaiswal
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Jan Benada
- Laboratory of Cancer Cell Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Erik Müllers
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Karen Akopyan
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Kamila Burdova
- Laboratory of Cancer Cell Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Tobias Koolmeister
- Department of Medical Biochemistry and Biophysics, and Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Thomas Helleday
- Department of Medical Biochemistry and Biophysics, and Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - René H Medema
- Division of Cell Biology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Libor Macurek
- Laboratory of Cancer Cell Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Arne Lindqvist
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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24
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Bruinsma W, Aprelia M, Kool J, Macurek L, Lindqvist A, Medema RH. Spatial Separation of Plk1 Phosphorylation and Activity. Front Oncol 2015; 5:132. [PMID: 26114094 PMCID: PMC4462105 DOI: 10.3389/fonc.2015.00132] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/26/2015] [Indexed: 01/05/2023] Open
Abstract
Polo-like kinase 1 (Plk1) is one of the major kinases controlling mitosis and cell division. Plk1 is first recruited to the centrosome in S phase, then appears on the kinetochores in late G2, and at the end of mitosis, it translocates to the central spindle. Activation of Plk1 requires phosphorylation of T210 by Aurora A, an event that critically depends on the co-factor Bora. However, conflicting reports exist as to where Plk1 is first activated. Phosphorylation of T210 is first observed at the centrosomes, but kinase activity seems to be restricted to the nucleus in the earlier phases of G2. Here, we demonstrate that Plk1 activity manifests itself first in the nucleus using a nuclear FRET-based biosensor for Plk1 activity. However, we find that Bora is restricted to the cytoplasm and that Plk1 is phosphorylated on T210 at the centrosomes. Our data demonstrate that while Plk1 activation occurs on centrosomes, downstream target phosphorylation by Plk1 first occurs in the nucleus. We discuss several explanations for this surprising separation of activation and function.
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Affiliation(s)
- Wytse Bruinsma
- Department of Cell Biology, The Netherlands Cancer Institute , Amsterdam , Netherlands ; Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands
| | - Melinda Aprelia
- Department of Cell Biology, The Netherlands Cancer Institute , Amsterdam , Netherlands ; Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands
| | - Jolanda Kool
- Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands
| | - Libor Macurek
- Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands ; Laboratory of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, v. v. i. , Prague , Czech Republic
| | - Arne Lindqvist
- Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands ; Department of Cell and Molecular Biology, Karolinska Institute , Stockholm , Sweden
| | - René H Medema
- Department of Cell Biology, The Netherlands Cancer Institute , Amsterdam , Netherlands ; Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands
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Hong CS, Ho W, Zhang C, Yang C, Elder JB, Zhuang Z. LB100, a small molecule inhibitor of PP2A with potent chemo- and radio-sensitizing potential. Cancer Biol Ther 2015; 16:821-33. [PMID: 25897893 DOI: 10.1080/15384047.2015.1040961] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that plays a significant role in mitotic progression and cellular responses to DNA damage. While traditionally viewed as a tumor suppressor, inhibition of PP2A has recently come to attention as a novel therapeutic means of driving senescent cancer cells into mitosis and promoting cell death via mitotic catastrophe. These findings have been corroborated in numerous studies utilizing naturally produced compounds that selectively inhibit PP2A. To overcome the known human toxicities associated with these compounds, a water-soluble small molecule inhibitor, LB100, was recently developed to competitively inhibit the PP2A protein. This review summarizes the pre-clinical studies to date that have demonstrated the anti-cancer activity of LB100 via its chemo- and radio-sensitizing properties. These studies demonstrate the tremendous therapeutic potential of LB100 in a variety of cancer types. The results of an ongoing phase 1 trial are eagerly anticipated.
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Key Words
- ABC, ATP-binding cassette.
- APC, adenomatous polyposis coli
- ARPP19, cyclic AMP-regulated phosphoprotein 19
- ATM, ataxia-telangiectasia mutated
- CIP2A, cancerous inhibitor of PP2A
- CNTF, ciliary neurotrophic factor
- DISC, death-inducing signaling complex
- DVL, dishevelled
- ENSA, α-endosulphine
- GBM, glioblastoma
- GFAP, glial fibrillary acidic protein
- HCC, hepatocellular carcinoma
- HDACs, histone deacetylase complexes
- HIF-1a, hypoxia-inducible factor-1a
- HRR, homologous recombination repair
- MDM2, mouse double minute 2 homolog
- MRI, magnetic resonance imaging
- NPC, nasopharyngeal carcinoma
- PP2A, protein phosphatase 2A
- Plk1, polo-like kinase 1
- TCTP, translationally-controlled tumor protein
- TMZ, temozolomide
- TRAIL, TNF-related apoptosis-inducing ligand
- VEGF, vascular endothelial growth factor
- cell cycle
- chemosensitization
- mitotic catastrophe
- protein phosphatase 2A
- radiosensitizationreview
- small molecule inhibitor
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Affiliation(s)
- Christopher S Hong
- a The Ohio State University Wexner Medical Center ; Department of Neurological Surgery ; Columbus , OH USA
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