1
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Zhao YS, Liu DX, Tan FQ, Yang WX. KIF2A Upregulates PI3K/AKT Signaling through Polo-like Kinase 1 (PLK1) to Affect the Proliferation and Apoptosis Levels of Eriocheir sinensis Spermatogenic Cells. BIOLOGY 2024; 13:149. [PMID: 38534420 DOI: 10.3390/biology13030149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/15/2024] [Accepted: 02/22/2024] [Indexed: 03/28/2024]
Abstract
E. sinensis is an animal model for studying the reproduction and development of crustaceans. In this study, we knocked down the Es-Kif2a gene by injecting dsRNA into E. sinensis and inhibited Es-Plk1 gene expression by injecting PLK1 inhibitor BI6727 into E. sinensis. Then, the cell proliferation level, apoptosis level, and PI3K/AKT signaling expression level were detected. Our results showed that the proliferation level of spermatogenic cells decreased, while the apoptosis level increased after Es-Kif2a knockdown or Es-Plk1 inhibition. In order to verify whether these changes are caused by regulating the PI3K/AKT pathway, we detected the expression of PI3K and AKT proteins after Es-Kif2a knockdown or Es-Plk1 inhibition. Western Blot showed that in both the Es-Kif2a knockdown group and the Es-Plk1 inhibition group, the expression of PI3K and AKT proteins decreased. In addition, immunofluorescence showed that Es-KIF2A and Es-PLK1 proteins were co-localized during E. sinensis spermatogenesis. To further explore the upstream and downstream relationship between Es-KIF2A and Es-PLK1, we detected the expression level of Es-PLK1 after Es-Kif2a knockdown as well as the expression level of Es-KIF2A after Es-Plk1 inhibition. Western Blot showed that the expression of Es-PLK1 decreased after Es-Kif2a knockdown, while there was no significant change of Es-KIF2A after Es-Plk1 inhibition, indicating that Es-PLK1 may be a downstream factor of Es-KIF2A. Taken together, these results suggest that Es-KIF2A upregulates the PI3K/AKT signaling pathway through Es-PLK1 during the spermatogenesis of E. sinensis, thereby affecting the proliferation and apoptosis levels of spermatogenic cells.
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Affiliation(s)
- Yan-Shuang Zhao
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ding-Xi Liu
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Fu-Qing Tan
- The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
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2
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Li Y, Wang F, Li X, Wang L, Yang Z, You Z, Peng A. The ATM-E6AP-MASTL axis mediates DNA damage checkpoint recovery. eLife 2023; 12:RP86976. [PMID: 37672026 PMCID: PMC10482428 DOI: 10.7554/elife.86976] [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] [Indexed: 09/07/2023] Open
Abstract
Checkpoint activation after DNA damage causes a transient cell cycle arrest by suppressing cyclin-dependent kinases (CDKs). However, it remains largely elusive how cell cycle recovery is initiated after DNA damage. In this study, we discovered the upregulated protein level of MASTL kinase hours after DNA damage. MASTL promotes cell cycle progression by preventing PP2A/B55-catalyzed dephosphorylation of CDK substrates. DNA damage-induced MASTL upregulation was caused by decreased protein degradation, and was unique among mitotic kinases. We identified E6AP as the E3 ubiquitin ligase that mediated MASTL degradation. MASTL degradation was inhibited upon DNA damage as a result of the dissociation of E6AP from MASTL. E6AP depletion reduced DNA damage signaling, and promoted cell cycle recovery from the DNA damage checkpoint, in a MASTL-dependent manner. Furthermore, we found that E6AP was phosphorylated at Ser-218 by ATM after DNA damage and that this phosphorylation was required for its dissociation from MASTL, the stabilization of MASTL, and the timely recovery of cell cycle progression. Together, our data revealed that ATM/ATR-dependent signaling, while activating the DNA damage checkpoint, also initiates cell cycle recovery from the arrest. Consequently, this results in a timer-like mechanism that ensures the transient nature of the DNA damage checkpoint.
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Affiliation(s)
- Yanqiu Li
- Department of Oral Biology, University of Nebraska Medical CenterLincolnUnited States
| | - Feifei Wang
- Department of Oral Biology, University of Nebraska Medical CenterLincolnUnited States
| | - Xin Li
- Department of Oral Biology, University of Nebraska Medical CenterLincolnUnited States
| | - Ling Wang
- Department of Oral Biology, University of Nebraska Medical CenterLincolnUnited States
| | - Zheng Yang
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. LouisSt. LouisUnited States
| | - Zhongsheng You
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. LouisSt. LouisUnited States
| | - Aimin Peng
- Department of Oral Biology, University of Nebraska Medical CenterLincolnUnited States
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3
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Li Y, Wang F, Li X, Wang L, Yang Z, You Z, Peng A. The ATM-E6AP-MASTL axis mediates DNA damage checkpoint recovery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.22.529521. [PMID: 36865136 PMCID: PMC9980089 DOI: 10.1101/2023.02.22.529521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Checkpoint activation after DNA damage causes a transient cell cycle arrest by suppressing CDKs. However, it remains largely elusive how cell cycle recovery is initiated after DNA damage. In this study, we discovered the upregulated protein level of MASTL kinase hours after DNA damage. MASTL promotes cell cycle progression by preventing PP2A/B55-catalyzed dephosphorylation of CDK substrates. DNA damage-induced MASTL upregulation was caused by decreased protein degradation, and was unique among mitotic kinases. We identified E6AP as the E3 ubiquitin ligase that mediated MASTL degradation. MASTL degradation was inhibited upon DNA damage as a result of the dissociation of E6AP from MASTL. E6AP depletion reduced DNA damage signaling, and promoted cell cycle recovery from the DNA damage checkpoint, in a MASTL-dependent manner. Furthermore, we found that E6AP was phosphorylated at Ser-218 by ATM after DNA damage and that this phosphorylation was required for its dissociation from MASTL, the stabilization of MASTL, and the timely recovery of cell cycle progression. Together, our data revealed that ATM/ATR-dependent signaling, while activating the DNA damage checkpoint, also initiates cell cycle recovery from the arrest. Consequently, this results in a timer-like mechanism that ensures the transient nature of the DNA damage checkpoint.
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Affiliation(s)
- Yanqiu Li
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, Nebraska, USA
| | - Feifei Wang
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, Nebraska, USA
| | - Xin Li
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, Nebraska, USA
| | - Ling Wang
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, Nebraska, USA
| | - Zheng Yang
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Zhongsheng You
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Aimin Peng
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, Nebraska, USA
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4
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Yam CQX, Lim HH, Surana U. DNA damage checkpoint execution and the rules of its disengagement. Front Cell Dev Biol 2022; 10:1020643. [PMID: 36274841 PMCID: PMC9582513 DOI: 10.3389/fcell.2022.1020643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Chromosomes are susceptible to damage during their duplication and segregation or when exposed to genotoxic stresses. Left uncorrected, these lesions can result in genomic instability, leading to cells’ diminished fitness, unbridled proliferation or death. To prevent such fates, checkpoint controls transiently halt cell cycle progression to allow time for the implementation of corrective measures. Prominent among these is the DNA damage checkpoint which operates at G2/M transition to ensure that cells with damaged chromosomes do not enter the mitotic phase. The execution and maintenance of cell cycle arrest are essential aspects of G2/M checkpoint and have been studied in detail. Equally critical is cells’ ability to switch-off the checkpoint controls after a successful completion of corrective actions and to recommence cell cycle progression. Interestingly, when corrective measures fail, cells can mount an unusual cellular response, termed adaptation, where they escape checkpoint arrest and resume cell cycle progression with damaged chromosomes at the cost of genome instability or even death. Here, we discuss the DNA damage checkpoint, the mitotic networks it inhibits to prevent segregation of damaged chromosomes and the strategies cells employ to quench the checkpoint controls to override the G2/M arrest.
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Affiliation(s)
| | - Hong Hwa Lim
- A*STAR Singapore Immunology Network, Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Uttam Surana
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Pharmacology, National University of Singapore, Singapore, Singapore
- *Correspondence: Uttam Surana,
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5
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Gouttia OG, Zhao J, Li Y, Zwiener MJ, Wang L, Oakley GG, Peng A. The MASTL-ENSA-PP2A/B55 axis modulates cisplatin resistance in oral squamous cell carcinoma. Front Cell Dev Biol 2022; 10:904719. [PMID: 36247015 PMCID: PMC9554306 DOI: 10.3389/fcell.2022.904719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/31/2022] [Indexed: 02/01/2023] Open
Abstract
Platinum-based chemotherapy is the standard first-line treatment for oral squamous cell carcinoma (OSCC) that is inoperable, recurrent, or metastatic. Platinum sensitivity is a major determinant of patient survival in advanced OSCC. Here, we investigated the involvement of MASTL, a cell cycle kinase that mediates ENSA/ARPP19 phosphorylation and PP2A/B55 inhibition, in OSCC therapy. Interestingly, upregulation of MASTL and ENSA/ARPP19, and downregulation of PP2A/B55, were common in OSCC. MASTL expression was in association with poor patient survival. In established OSCC cell lines, upregulation of MASTL and ENSA, and downregulation of B55 genes, correlated with cisplatin resistance. We further confirmed that stable expression of MASTL in OSCC cells promoted cell survival and proliferation under cisplatin treatment, in an ENSA-dependent manner. Conversely, deletion of MASTL or ENSA, or overexpression of B55α, sensitized cisplatin response, consistent with increased DNA damage accumulation, signaling, and caspase activation. Moreover, GKI-1, the first-in-class small molecule inhibitor of MASTL kinase, phenocopied MASTL depletion in enhancing the outcome of cisplatin treatment in OSCC cells, at a dose substantially lower than that needed to disrupt mitotic entry. Finally, GKI-1 exhibited promising efficacy in a mouse tumor xenograft model, in conjunction with cisplatin therapy.
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6
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SILAC kinase screen identifies potential MASTL substrates. Sci Rep 2022; 12:10568. [PMID: 35732702 PMCID: PMC9217955 DOI: 10.1038/s41598-022-14933-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/15/2022] [Indexed: 12/04/2022] Open
Abstract
Microtubule-associated serine/threonine kinase-like (MASTL) has emerged as a critical regulator of mitosis and as a potential oncogene in a variety of cancer types. To date, Arpp-19/ENSA are the only known substrates of MASTL. However, with the roles of MASTL expanding and increased interest in development of MASTL inhibitors, it has become critical to determine if there are additional substrates and what the optimal consensus motif for MASTL is. Here we utilized a whole cell lysate in vitro kinase screen combined with stable isotope labelling of amino acids in cell culture (SILAC) to identify potential substrates and the residue preference of MASTL. Using the related AGC kinase family members AKT1/2, the kinase screen identified several known and new substrates highly enriched for the validated consensus motif of AKT. Applying this method to MASTL identified 59 phospho-sites on 67 proteins that increased in the presence of active MASTL. Subsequent in vitro kinase assays suggested that MASTL may phosphorylate hnRNPM, YB1 and TUBA1C under certain in vitro conditions. Taken together, these data suggest that MASTL may phosphorylate several additional substrates, providing insight into the ever-increasing biological functions and roles MASTL plays in driving cancer progression and therapy resistance.
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7
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Kim AY, Yoon YN, Leem J, Lee JY, Jung KY, Kang M, Ahn J, Hwang SG, Oh JS, Kim JS. MKI-1, a Novel Small-Molecule Inhibitor of MASTL, Exerts Antitumor and Radiosensitizer Activities Through PP2A Activation in Breast Cancer. Front Oncol 2020; 10:571601. [PMID: 33117702 PMCID: PMC7550800 DOI: 10.3389/fonc.2020.571601] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/02/2020] [Indexed: 12/16/2022] Open
Abstract
Although MASTL (microtubule-associated serine/threonine kinase-like) is an attractive target for anticancer treatment, MASTL inhibitors with antitumor activity have not yet been reported. In this study, we have presented a novel MASTL inhibitor, MKI-1, identified through in silico screening and in vitro analysis. Our data revealed that MKI-1 exerted antitumor and radiosensitizer activities in in vitro and in vivo models of breast cancer. The mechanism of action of MKI-1 occurred through an increase in PP2A activity, which subsequently decreased the c-Myc protein content in breast cancer cells. Moreover, the activity of MKI-1 in the regulation of MASTL-PP2A was validated in a mouse oocyte model. Our results have demonstrated a new small-molecule inhibitor of MASTL, MKI-1, which exerts antitumor and radiosensitizer activities through PP2A activation in breast cancer in vitro and in vivo.
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Affiliation(s)
- Ah-Young Kim
- Division of Radiation Biomedical Research, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Yi Na Yoon
- Division of Radiation Biomedical Research, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea.,Radiological and Medico-Oncological Sciences, University of Science and Technology, Daejeon, South Korea
| | - Jiyeon Leem
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
| | - Jee-Young Lee
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South Korea
| | - Kwan-Young Jung
- Center for Medicinal Chemistry, Korea Research Institute of Chemical Technology, Daejeon, South Korea
| | - Minsung Kang
- Division of Radiation Biomedical Research, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Jiyeon Ahn
- Division of Radiation Biomedical Research, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Sang-Gu Hwang
- Division of Radiation Biomedical Research, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Jeong Su Oh
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
| | - Jae-Sung Kim
- Division of Radiation Biomedical Research, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea.,Radiological and Medico-Oncological Sciences, University of Science and Technology, Daejeon, South Korea
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8
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Hermida D, Mortuza GB, Pedersen AK, Pozdnyakova I, Nguyen TTTN, Maroto M, Williamson M, Ebersole T, Cazzamali G, Rand K, Olsen JV, Malumbres M, Montoya G. Molecular Basis of the Mechanisms Controlling MASTL. Mol Cell Proteomics 2020; 19:326-343. [PMID: 31852836 PMCID: PMC7000116 DOI: 10.1074/mcp.ra119.001879] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Indexed: 12/16/2022] Open
Abstract
The human MASTL (Microtubule-associated serine/threonine kinase-like) gene encodes an essential protein in the cell cycle. MASTL is a key factor preventing early dephosphorylation of M-phase targets of Cdk1/CycB. Little is known about the mechanism of MASTL activation and regulation. MASTL contains a non-conserved insertion of 550 residues within its activation loop, splitting the kinase domain, and making it unique. Here, we show that this non-conserved middle region (NCMR) of the protein is crucial for target specificity and activity. We performed a phosphoproteomic assay with different MASTL constructs identifying key phosphorylation sites for its activation and determining whether they arise from autophosphorylation or exogenous kinases, thus generating an activation model. Hydrogen/deuterium exchange data complements this analysis revealing that the C-lobe in full-length MASTL forms a stable structure, whereas the N-lobe is dynamic and the NCMR and C-tail contain few localized regions with higher-order structure. Our results indicate that truncated versions of MASTL conserving a cryptic C-Lobe in the NCMR, display catalytic activity and different targets, thus establishing a possible link with truncated mutations observed in cancer-related databases.
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Affiliation(s)
- Dario Hermida
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Gulnahar B Mortuza
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Anna-Kathrine Pedersen
- The Novo Nordisk Foundation Center for Protein Research, Proteomics Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Irina Pozdnyakova
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Tam T T N Nguyen
- Protein Analysis Group, Department of Pharmacy, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagen, Denmark
| | - Maria Maroto
- Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain
| | - Michael Williamson
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Tasja Ebersole
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Giuseppe Cazzamali
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Kasper Rand
- Protein Analysis Group, Department of Pharmacy, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagen, Denmark
| | - Jesper V Olsen
- The Novo Nordisk Foundation Center for Protein Research, Proteomics Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Marcos Malumbres
- Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain
| | - Guillermo Montoya
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
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9
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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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10
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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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11
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Luong KV, Wang L, Roberts BJ, Wahl JK, Peng A. Cell fate determination in cisplatin resistance and chemosensitization. Oncotarget 2018; 7:23383-94. [PMID: 26993599 PMCID: PMC5029634 DOI: 10.18632/oncotarget.8110] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 02/28/2016] [Indexed: 01/22/2023] Open
Abstract
Understanding the determination of cell fate choices after cancer treatment will shed new light on cancer resistance. In this study, we quantitatively analyzed the individual cell fate choice in resistant UM-SCC-38 head and neck cancer cells exposed to cisplatin. Our study revealed a highly heterogeneous pattern of cell fate choices in UM-SCC-38 cells, in comparison to that of the control, non-tumorigenic keratinocyte HaCaT cells. In both UM-SCC-38 and HaCaT cell lines, the majority of cell death occurred during the immediate interphase without mitotic entry, whereas significant portions of UM-SCC-38 cells survived the treatment via either checkpoint arrest or checkpoint slippage. Interestingly, checkpoint slippage occurred predominantly in cells treated in late S and G2 phases, and cells in M-phase were hypersensitive to cisplatin. Moreover, although the cisplatin-resistant progression of mitosis exhibited no delay in general, prolonged mitosis was correlated with the induction of cell death in mitosis. The finding thus suggested a combinatorial treatment using cisplatin and an agent that blocks mitotic exit. Consistently, we showed a strong synergy between cisplatin and the proteasome inhibitor Mg132. Finally, targeting the DNA damage checkpoint using inhibitors of ATR, but not ATM, effectively sensitized UM-SCC-38 to cisplatin treatment. Surprisingly, checkpoint targeting eliminated both checkpoint arrest and checkpoint slippage, and augmented the induction of cell death in interphase without mitotic entry. Taken together, our study, by profiling cell fate determination after cisplatin treatment, reveals new insights into chemoresistance and suggests combinatorial strategies that potentially overcome cancer resistance.
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Affiliation(s)
- Khanh V Luong
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
| | - Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
| | - Brett J Roberts
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
| | - James K Wahl
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
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12
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Ren D, Fisher LA, Zhao J, Wang L, Williams BC, Goldberg ML, Peng A. Cell cycle-dependent regulation of Greatwall kinase by protein phosphatase 1 and regulatory subunit 3B. J Biol Chem 2017; 292:10026-10034. [PMID: 28446604 DOI: 10.1074/jbc.m117.778233] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/25/2017] [Indexed: 11/06/2022] Open
Abstract
Greatwall (Gwl) kinase plays an essential role in the regulation of mitotic entry and progression. Mitotic activation of Gwl requires both cyclin-dependent kinase 1 (CDK1)-dependent phosphorylation and its autophosphorylation at an evolutionarily conserved serine residue near the carboxyl terminus (Ser-883 in Xenopus). In this study we show that Gwl associates with protein phosphatase 1 (PP1), particularly PP1γ, which mediates the dephosphorylation of Gwl Ser-883. Consistent with the mitotic activation of Gwl, its association with PP1 is disrupted in mitotic cells and egg extracts. During mitotic exit, PP1-dependent dephosphorylation of Gwl Ser-883 occurs prior to dephosphorylation of other mitotic substrates; replacing endogenous Gwl with a phosphomimetic S883E mutant blocks mitotic exit. Moreover, we identified PP1 regulatory subunit 3B (PPP1R3B) as a targeting subunit that can direct PP1 activity toward Gwl. PPP1R3B bridges PP1 and Gwl association and promotes Gwl Ser-883 dephosphorylation. Consistent with the cell cycle-dependent association of Gwl and PP1, Gwl and PPP1R3B dissociate in M phase. Interestingly, up-regulation of PPP1R3B facilitates mitotic exit and blocks mitotic entry. Thus, our study suggests PPP1R3B as a new cell cycle regulator that functions by governing Gwl dephosphorylation.
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Affiliation(s)
- Dapeng Ren
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583 and
| | - Laura A Fisher
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583 and
| | - Jing Zhao
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583 and
| | - Ling Wang
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583 and
| | - Byron C Williams
- the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Michael L Goldberg
- the Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Aimin Peng
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583 and
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13
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Wong PY, Ma HT, Lee HJ, Poon RYC. MASTL(Greatwall) regulates DNA damage responses by coordinating mitotic entry after checkpoint recovery and APC/C activation. Sci Rep 2016; 6:22230. [PMID: 26923777 PMCID: PMC4770598 DOI: 10.1038/srep22230] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/08/2016] [Indexed: 11/09/2022] Open
Abstract
The G2 DNA damage checkpoint is one of the most important mechanisms controlling G2-mitosis transition. The kinase Greatwall (MASTL in human) promotes normal G2-mitosis transition by inhibiting PP2A via ARPP19 and ENSA. In this study, we demonstrate that MASTL is critical for maintaining genome integrity after DNA damage. Although MASTL did not affect the activation of DNA damage responses and subsequent repair, it determined the timing of entry into mitosis and the subsequent fate of the recovering cells. Constitutively active MASTL promoted dephosphorylation of CDK1(Tyr15) and accelerated mitotic entry after DNA damage. Conversely, downregulation of MASTL or ARPP19/ENSA delayed mitotic entry. Remarkably, APC/C was activated precociously, resulting in the damaged cells progressing from G2 directly to G1 and skipping mitosis all together. Collectively, these results established that precise control of MASTL is essential to couple DNA damage to mitosis through the rate of mitotic entry and APC/C activation.
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Affiliation(s)
- Po Yee Wong
- Division of Life Science, Center for Cancer Research, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Hoi Tang Ma
- Division of Life Science, Center for Cancer Research, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Hyun-jung Lee
- Division of Life Science, Center for Cancer Research, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Randy Y C Poon
- Division of Life Science, Center for Cancer Research, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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14
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Wang L, Luong VQ, Giannini PJ, Peng A. Mastl kinase, a promising therapeutic target, promotes cancer recurrence. Oncotarget 2015; 5:11479-89. [PMID: 25373736 PMCID: PMC4294390 DOI: 10.18632/oncotarget.2565] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/03/2014] [Indexed: 11/25/2022] Open
Abstract
Mastl kinase promotes mitotic progression and cell cycle reentry after DNA damage. We report here that Mastl is frequently upregulated in various types of cancer. This upregulation was correlated with cancer progression in breast and oral cancer, poor patient survival in breast cancer, and tumor recurrence in head and neck squamous cell carcinoma. We further investigated the role of Mastl in tumor resistance using cell lines derived from the initial and recurrent tumors of the same head and neck squamous cell carcinoma patients. Ectopic expression of Mastl in the initial tumor cells strongly promoted cell proliferation in the presence of cisplatin by attenuating DNA damage signaling and cell death. Mastl knockdown in recurrent tumor cells re-sensitized their response to cancer therapy in vitro and in vivo. Finally, Mastl targeting specifically potentiated cancer cells to cell death in chemotherapy while sparing normal cells. Thus, this study revealed that Mastl upregulation is involved in cancer progression and tumor recurrence after initial cancer therapy, and validated Mastl as a promising target to increase the therapeutic window.
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Affiliation(s)
- Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583
| | - Vivian Q Luong
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583
| | - Peter J Giannini
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583
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15
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Yamamoto TM, Wang L, Fisher LA, Eckerdt FD, Peng A. Regulation of Greatwall kinase by protein stabilization and nuclear localization. Cell Cycle 2015; 13:3565-75. [PMID: 25483093 DOI: 10.4161/15384101.2014.962942] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Greatwall (Gwl) functions as an essential mitotic kinase by antagonizing protein phosphatase 2A. In this study we identified Hsp90, Cdc37 and members of the importin α and β families as the major binding partners of Gwl. Both Hsp90/Cdc37 chaperone and importin complexes associated with the N-terminal kinase domain of Gwl, whereas an intact glycine-rich loop at the N-terminus of Gwl was essential for binding of Hsp90/Cdc37 but not importins. We found that Hsp90 inhibition led to destabilization of Gwl, a mechanism that may partially contribute to the emerging role of Hsp90 in cell cycle progression and the anti-proliferative potential of Hsp90 inhibition. Moreover, in agreement with its importin association, Gwl exhibited nuclear localization in interphase Xenopus S3 cells, and dynamic nucleocytoplasmic distribution during mitosis. We identified KR456/457 as the locus of importin binding and the functional NLS of Gwl. Mutation of this site resulted in exclusion of Gwl from the nucleus. Finally, we showed that the Gwl nuclear localization is indispensable for the biochemical function of Gwl in promoting mitotic entry.
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Affiliation(s)
- Tomomi M Yamamoto
- a Department of Oral Biology ; University of Nebraska Medical Center ; Lincoln , NE USA
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16
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Wang H, Zhang X, Teng L, Legerski RJ. DNA damage checkpoint recovery and cancer development. Exp Cell Res 2015; 334:350-8. [PMID: 25842165 DOI: 10.1016/j.yexcr.2015.03.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/12/2015] [Accepted: 03/14/2015] [Indexed: 12/21/2022]
Abstract
Cell cycle checkpoints were initially presumed to function as a regulator of cell cycle machinery in response to different genotoxic stresses, and later found to play an important role in the process of tumorigenesis by acting as a guard against DNA over-replication. As a counterpart of checkpoint activation, the checkpoint recovery machinery is working in opposition, aiming to reverse the checkpoint activation and resume the normal cell cycle. The DNA damage response (DDR) and oncogene induced senescence (OIS) are frequently found in precancerous lesions, and believed to constitute a barrier to tumorigenesis, however, the DDR and OIS have been observed to be diminished in advanced cancers of most tissue origins. These findings suggest that when progressing from pre-neoplastic lesions to cancer, DNA damage checkpoint barriers are overridden. How the DDR checkpoint is bypassed in this process remains largely unknown. Activated cytokine and growth factor-signaling pathways were very recently shown to suppress the DDR and to promote uncontrolled cell proliferation in the context of oncovirus infection. In recent decades, data from cell line and tumor models showed that a group of checkpoint recovery proteins function in promoting tumor progression; data from patient samples also showed overexpression of checkpoint recovery proteins in human cancer tissues and a correlation with patients׳ poor prognosis. In this review, the known cell cycle checkpoint recovery proteins and their roles in DNA damage checkpoint recovery are reviewed, as well as their implications in cancer development. This review also provides insight into the mechanism by which the DDR suppresses oncogene-driven tumorigenesis and tumor progression.
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Affiliation(s)
- Haiyong Wang
- First affiliated hospital, Zhejiang University, School of medicine, Cancer Center, 79 Qingchun Road, Hangzhou 310003, China
| | - Xiaoshan Zhang
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Department of Genetics Unit 1010, 1515 Holcombe Blvd. Houston, TX 77030 USA
| | - Lisong Teng
- First affiliated hospital, Zhejiang University, School of medicine, Cancer Center, 79 Qingchun Road, Hangzhou 310003, China.
| | - Randy J Legerski
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Department of Genetics Unit 1010, 1515 Holcombe Blvd. Houston, TX 77030 USA.
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17
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Wang L, Guo Q, Fisher LA, Liu D, Peng A. Regulation of polo-like kinase 1 by DNA damage and PP2A/B55α. Cell Cycle 2015; 14:157-66. [PMID: 25483054 PMCID: PMC4615057 DOI: 10.4161/15384101.2014.986392] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 11/03/2014] [Accepted: 11/06/2014] [Indexed: 12/24/2022] Open
Abstract
In addition to governing mitotic progression, Plk1 also suppresses the activation of the G2 DNA damage checkpoint and promotes checkpoint recovery. Previous studies have shown that checkpoint activation after DNA damage requires inhibition of Plk1, but the underlying mechanism of Plk1 regulation was unknown. In this study we show that the specific phosphatase activity toward Plk1 Thr-210 in interphase Xenopus egg extracts is predominantly PP2A-dependent, and this phosphatase activity is upregulated by DNA damage. Consistently, PP2A associates with Plk1 and the association increases after DNA damage. We further revealed that B55α, a targeting subunit of PP2A and putative tumor suppressor, mediates PP2A/Plk1 association and Plk1 dephosphorylation. B55α and PP2A association is greatly strengthened after DNA damage in an ATM/ATR and checkpoint kinase-dependent manner. Collectively, we report a phosphatase-dependent mechanism that responds to DNA damage and regulates Plk1 and checkpoint recovery.
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Affiliation(s)
- Ling Wang
- Department of Oral Biology; College of Dentistry; University of Nebraska Medical Center; Lincoln, NE USA
| | - Qingyuan Guo
- Department of Oral Biology; College of Dentistry; University of Nebraska Medical Center; Lincoln, NE USA
- Department of Orthodontics; Shandong Provincial Key Laboratory of Oral Biomedicine; Shandong University; Jinan, China
| | - Laura A Fisher
- Department of Oral Biology; College of Dentistry; University of Nebraska Medical Center; Lincoln, NE USA
| | - Dongxu Liu
- Department of Orthodontics; Shandong Provincial Key Laboratory of Oral Biomedicine; Shandong University; Jinan, China
| | - Aimin Peng
- Department of Oral Biology; College of Dentistry; University of Nebraska Medical Center; Lincoln, NE USA
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18
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Zhao X, Yu D, Feng C, Deng X, Wu D, Jin M, Wang E, Wang X, Yu B. Role of Greatwall kinase in release of mouse oocytes from diplotene arrest. Dev Growth Differ 2014; 56:669-78. [PMID: 25472593 DOI: 10.1111/dgd.12183] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/22/2014] [Accepted: 09/15/2014] [Indexed: 11/27/2022]
Abstract
In eukaryotes, mitosis entry is induced by activation of maturation-promoting factor (MPF), which is regulated by a network of kinases and phosphatases. It has been suggested that Greatwall (GWL) kinase was crucial for the M-phase entry and could maintain cyclin B-Cdc2 activity through regulation of protein phosphatase 2A (PP2A), a counteracting phosphatase of MPF. Here, the role of GWL was assessed during release of mouse oocytes from prophase I arrest. GWL was crucial for meiotic maturation in mouse oocytes. As a positive regulator for meiosis resumption, GWL was continually expressed in germinal vesicle (GV) and MII stage oocytes and two-cell stage embryos. Additionally, GWL localized to the nucleus and dispersed into cytoplasm during GV breakdown (GVBD). Furthermore, downregulation of GWL or overexpression of catalytically-inactive GWL inhibited partial meiotic maturation. This prophase I arrest induced by GWL depletion could be rescued by the PP2A inhibition. However, both GWL-depleted and rescued oocytes had severe spindle defects that hardly reached MII. In contrast, oocytes overexpressing wild-type GWL resumed meiosis and progressed to MII stage. Thus, our data demonstrate that GWL acts in a pathway with PP2A which is essential for prophase I exit and metaphase I microtubule assembly in mouse oocytes.
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Affiliation(s)
- Xiangyu Zhao
- Department of Biochemical and Molecular Biology, China Medical University, Shenyang, Liaoning Province, China
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19
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Schmucker S, Sumara I. Molecular dynamics of PLK1 during mitosis. Mol Cell Oncol 2014; 1:e954507. [PMID: 27308323 PMCID: PMC4905186 DOI: 10.1080/23723548.2014.954507] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 12/30/2022]
Abstract
Polo-like kinase 1 (PLK1) is a key regulator of eukaryotic cell division. During mitosis, dynamic regulation of PLK1 is crucial for its roles in centrosome maturation, spindle assembly, microtubule–kinetochore attachment, and cytokinesis. Similar to other members of the PLK family, the molecular architecture of PLK1 protein is characterized by 2 domains—the kinase domain and the regulatory substrate-binding domain (polo-box domain)—that cooperate and control PLK1 function during mitosis. Mitotic cells employ many layers of regulation to activate and target PLK1 to different cellular structures in a timely manner. During the last decade, numerous studies have shed light on the precise molecular mechanisms orchestrating the mitotic activity of PLK1 in time and space. This review aims to discuss available data and concepts related to regulation of the molecular dynamics of human PLK1 during mitotic progression.
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Affiliation(s)
- Stephane Schmucker
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) ; Illkirch, France
| | - Izabela Sumara
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) ; Illkirch, France
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20
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Fisher LA, Wang L, Wu L, Peng A. Phosphatase 1 nuclear targeting subunit is an essential regulator of M-phase entry, maintenance, and exit. J Biol Chem 2014; 289:23745-52. [PMID: 25002584 DOI: 10.1074/jbc.m114.572149] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitotic progression is regulated largely through dynamic and reversible protein phosphorylation that is modulated by opposing actions of protein kinases and phosphatases. In this study, we show that phosphatase 1 nuclear targeting subunit (Pnuts) functions as a master regulator of mitosis by modulating protein phosphatase 1 (PP1). Overexpression of Pnuts in Xenopus egg extracts inhibited both mitotic and meiotic exit. Immunodepletion of Pnuts from egg extracts revealed its essential functions in mitotic entry and maintenance. The level of Pnuts oscillates during the cell cycle and peaks in mitosis. Pnuts destruction during M-phase exit is mediated by the anaphase-promoting complex/cyclosome (APC/C)-targeted ubiquitination and proteolysis, and conserved destruction motifs of Pnuts. Disruption of Pnuts degradation delayed M-phase exit, suggesting it as an important mechanism to permit M-phase exit.
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Affiliation(s)
- Laura A Fisher
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583
| | - Ling Wang
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583
| | - Lan Wu
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583
| | - Aimin Peng
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583
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21
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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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22
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Abstract
Cell cycle progression is largely controlled by reversible protein phosphorylation mediated by cyclically activated kinases and phosphatases. It has long been known that cyclin B-Cdk1 activation triggers mitotic entry, and the enzymatic network controlling its activation and inactivation has been well characterized. Much more recently protein phosphatase 2A (PP2A) together with its B55 regulatory subunit has been recognized as the major activity dephosphorylating Cdk1 targets. Moreover, PP2A-B55 activity is high in late M phase and interphase, but low at mitotic entry. A series of discoveries in the fly and frog model systems have uncovered the molecular mechanism mediating this regulation. The Greatwall (Gwl) kinase activates endosulfines, which become specific inhibitors of PP2A-B55. Cdk1-dependent activation of Gwl at mitotic entry leads to PP2A-B55 downregulation, which synergizes with Cdk1 activation to promote the phosphorylated states of several mitotic substrates. Much less is known on the mechanisms inactivating Gwl and endosulfines at mitotic exit. Recent reports show the importance of spatiotemporal regulation of Gwl, endosulfines, and PP2A-B55 for cell cycle progression. The various systems and cell types differ in their dependence on the Gwl-PP2A axis for cell cycle progression. Moreover, this pathway also regulates gene expression in yeast, and this function could be conserved in metazoans.
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Affiliation(s)
- Peng Wang
- Department of Biochemistry, Institut de recherche en immunologie et en cancérologie, Université de Montréal, Édouard-Montpetit Blvd., Montréal, QC, Canada, H3T 1J4
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23
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Glover DM. The overlooked greatwall: a new perspective on mitotic control. Open Biol 2013; 2:120023. [PMID: 22754657 PMCID: PMC3382961 DOI: 10.1098/rsob.120023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 03/02/2012] [Indexed: 01/31/2023] Open
Abstract
The role of the dual specificity protein phosphatase, Cdc25, in activating the cyclin-dependent kinase-cyclin B complex (Cdk1-CycB) by overcoming the inhibitory Wee1 kinase is a long-established principle for mitotic entry. Recently, however, evidence has emerged of a regulatory network that facilitates Cdk1-CycB activity by inhibiting the form of protein phosphatase 2A having a B55 regulatory subunit (PP2A-B55). Here, I review the genetic and biochemical evidence for Greatwall kinase and its substrate Endosulphine as the key components of this previously obscure regulatory network. Not only is the inhibition of PP2A-B55 by phospho-endosulphine required to prevent dephosphorylation of Cdk1-CycB substrates until mitotic exit, but it is also required to promote Cdc25 activity and inhibit Wee1 at mitotic entry. I discuss how these alternating states of preferential PP2A-B55 or Cdk1-CycB activity can have an impact upon the regulation of Polo kinase and its ability to bind different partner proteins as mitosis progresses.
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Affiliation(s)
- David M Glover
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB3 9JW, UK.
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24
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Li YH, Kang H, Xu YN, Heo YT, Cui XS, Kim NH, Oh JS. Greatwall Kinase Is Required for Meiotic Maturation in Porcine Oocytes1. Biol Reprod 2013; 89:53. [DOI: 10.1095/biolreprod.113.109850] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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25
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Replication checkpoint: tuning and coordination of replication forks in s phase. Genes (Basel) 2013; 4:388-434. [PMID: 24705211 PMCID: PMC3924824 DOI: 10.3390/genes4030388] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/30/2013] [Accepted: 08/02/2013] [Indexed: 12/01/2022] Open
Abstract
Checkpoints monitor critical cell cycle events such as chromosome duplication and segregation. They are highly conserved mechanisms that prevent progression into the next phase of the cell cycle when cells are unable to accomplish the previous event properly. During S phase, cells also provide a surveillance mechanism called the DNA replication checkpoint, which consists of a conserved kinase cascade that is provoked by insults that block or slow down replication forks. The DNA replication checkpoint is crucial for maintaining genome stability, because replication forks become vulnerable to collapse when they encounter obstacles such as nucleotide adducts, nicks, RNA-DNA hybrids, or stable protein-DNA complexes. These can be exogenously induced or can arise from endogenous cellular activity. Here, we summarize the initiation and transduction of the replication checkpoint as well as its targets, which coordinate cell cycle events and DNA replication fork stability.
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26
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Wang P, Galan JA, Normandin K, Bonneil É, Hickson GR, Roux PP, Thibault P, Archambault V. Cell cycle regulation of Greatwall kinase nuclear localization facilitates mitotic progression. ACTA ACUST UNITED AC 2013; 202:277-93. [PMID: 23857770 PMCID: PMC3718974 DOI: 10.1083/jcb.201211141] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Greatwall kinase relocation from the nucleus to the cytoplasm is required at mitotic entry and is mediated by a phosphorylation-dependent mechanism targeting its central region. Cell division requires the coordination of critical protein kinases and phosphatases. Greatwall (Gwl) kinase activity inactivates PP2A-B55 at mitotic entry to promote the phosphorylation of cyclin B–Cdk1 substrates, but how Gwl is regulated is poorly understood. We found that the subcellular localization of Gwl changed dramatically during the cell cycle in Drosophila. Gwl translocated from the nucleus to the cytoplasm in prophase. We identified two critical nuclear localization signals in the central, poorly characterized region of Gwl, which are required for its function. The Polo kinase associated with and phosphorylated Gwl in this region, promoting its binding to 14-3-3ε and its localization to the cytoplasm in prophase. Our results suggest that cyclin B–Cdk1 phosphorylation of Gwl is also required for its nuclear exclusion by a distinct mechanism. We show that the nucleo-cytoplasmic regulation of Gwl is essential for its functions in vivo and propose that the spatial regulation of Gwl at mitotic entry contributes to the mitotic switch.
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Affiliation(s)
- Peng Wang
- Institut de recherche en immunologie et en cancérologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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27
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Peng A. Working hard for recovery: mitotic kinases in the DNA damage checkpoint. Cell Biosci 2013; 3:20. [PMID: 23618492 PMCID: PMC3641994 DOI: 10.1186/2045-3701-3-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/28/2013] [Indexed: 11/10/2022] Open
Abstract
Cell division in mitosis is tightly regulated via a group of protein kinases. Activation of these mitotic kinases is inhibited by the DNA damage checkpoint that arrests the cell cycle in interphase and prevents mitotic entry. Interestingly, it has been shown that the DNA damage checkpoint is feedback regulated by several mitotic kinases. These kinases are reactivated from checkpoint arrest to deactivate the checkpoint and restart cell cycle progression, thereby allowing the cell to recover from the DNA damage checkpoint. The emerging role of mitotic kinases in the DNA damage pathway provides important insights into cancer progression and treatment.
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Affiliation(s)
- Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA.
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28
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Bruinsma W, Raaijmakers JA, Medema RH. Switching Polo-like kinase-1 on and off in time and space. Trends Biochem Sci 2012; 37:534-42. [PMID: 23141205 DOI: 10.1016/j.tibs.2012.09.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 09/16/2012] [Accepted: 09/21/2012] [Indexed: 01/24/2023]
Abstract
Polo-like kinase (Plk)1 executes several essential functions to promote cell division. These functions range from centrosome maturation in late G2 phase to the regulation of cytokinesis, which necessitates precise separation of Plk1-dependent substrate phosphorylation over time. Multiple levels of control are in place to ensure that Plk1-dependent phosphorylation of its various substrates is properly coordinated in time and space. Here, we review the current knowledge on the mechanisms that enforce the temporal and spatial control of Plk1 activity, and how this results in coordinated phosphorylation of its many different substrates. We also review a number of newly discovered functions of Plk1 that provide more insights into the spatiotemporal control of Plk1-dependent substrate phosphorylation.
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Affiliation(s)
- Wytse Bruinsma
- Department of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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29
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Wang L, Mosel AJ, Oakley GG, Peng A. Deficient DNA damage signaling leads to chemoresistance to cisplatin in oral cancer. Mol Cancer Ther 2012; 11:2401-9. [PMID: 22973056 DOI: 10.1158/1535-7163.mct-12-0448] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Activation of the cellular DNA damage response (DDR) is an important determinant of cell sensitivity to cisplatin and other chemotherapeutic drugs that eliminate tumor cells through induction of DNA damage. It is therefore important to investigate whether alterations of the DNA damage-signaling pathway confer chemoresistance in cancer cells and whether pharmacologic manipulation of the DDR pathway can resensitize these cells to cancer therapy. In a panel of oral/laryngeal squamous cell carcinoma (SCC) cell lines, we observed deficiencies in DNA damage signaling in correlation with cisplatin resistance, but not with DNA repair. These deficiencies are consistent with reduced expression of components of the ataxia telangiectasia mutated (ATM)-dependent signaling pathway and, in particular, strong upregulation of Wip1, a negative regulator of the ATM pathway. Wip1 knockdown or inhibition enhanced DNA damage signaling and resensitized oral SCC cells to cisplatin. In contrast to the previously reported involvement of Wip1 in cancer, Wip1 upregulation and function in these SCC cells is independent of p53. Finally, using xenograft tumor models, we showed that Wip1 upregulation promotes tumorigenesis and its inhibition improves the tumor response to cisplatin. Thus, this study reveals that chemoresistance in oral SCCs is partially attributed to deficiencies in DNA damage signaling, and Wip1 is an effective drug target for enhanced cancer therapy.
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Affiliation(s)
- Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
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30
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Abstract
New data have recently established that protein phosphorylation during mitosis is the result of a controlled balance between kinase and phosphatase activities and that, as for mitotic kinases, phosphatases are also regulated during cell division. This regulation is at least in part induced by the activation of the Greatwall (Gwl) kinase at mitotic entry. Activated Gwl phosphorylates its substrates cAMP-regulated phospho protein 19 (Arpp19) and α-endosulfine (ENSA), promoting their binding to and the inhibition of PP2A. Interestingly, besides the role of the Gwl-Arpp19/ENSA in the control of mitotic division, new data in yeast support the involvement of this pathway in mRNA stabilization during G(0) program initiation, although in this case the phosphatase PP2A appears not to be implicated. Finally, Gwl activity has been shown to be required for DNA checkpoint recovery. These new findings support the view that Gwl, Arpp19 and ENSA could function as the core of a new signalization pathway that, by targeting different final substrates, could participate in a variety of physiological functions.
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