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Pravoverov K, Fatima I, Barman S, Jühling F, Primeaux M, Baumert TF, Singh AB, Dhawan P. IL-22 regulates MASTL expression in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2024; 327:G123-G139. [PMID: 38771154 DOI: 10.1152/ajpgi.00260.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 05/09/2024] [Accepted: 05/09/2024] [Indexed: 05/22/2024]
Abstract
Microtubule-associated serine-threonine kinase-like (MASTL) has recently been identified as an oncogenic kinase given its overexpression in numerous cancers. Our group has shown that MASTL expression is upregulated in mouse models of sporadic colorectal cancer and colitis-associated cancer (CAC). CAC is one of the most severe complications of chronic inflammatory bowel disease (IBD), but a limited understanding of the mechanisms governing the switch from normal healing to neoplasia in IBD underscores the need for increased research in this area. However, MASTL levels in patients with IBD and its molecular regulation in IBD and CAC have not been studied. This study reveals that MASTL is upregulated by the cytokine interleukin (IL)-22, which promotes proliferation and has important functions in colitis recovery; however, IL-22 can also promote tumorigenesis when chronically elevated. Upon reviewing the publicly available data, we found significantly elevated MASTL and IL-22 levels in the biopsies from patients with late-stage ulcerative colitis compared with controls, and that MASTL upregulation was associated with high IL-22 expression. Our subsequent in vitro studies found that IL-22 increases MASTL expression in intestinal epithelial cell lines, which facilitates IL-22-mediated cell proliferation and downstream survival signaling. Inhibition of AKT activation abrogated IL-22-induced MASTL upregulation. We further found an increased association of carbonic anhydrase IX (CAIX) with MASTL in IL-22-treated cells, which stabilized MASTL expression. Inhibition of CAIX prevented IL-22-induced MASTL expression and cell survival. Overall, we show that IL-22/AKT signaling increases MASTL expression to promote cell survival and proliferation. Furthermore, CAIX associates with and stabilizes MASTL in response to IL-22 stimulation.NEW & NOTEWORTHY MASTL is upregulated in colorectal cancer; however, its role in colitis and colitis-associated cancer is poorly understood. This study is the first to draw a link between MASTL and IL-22, a proinflammatory/intestinal epithelial recovery-promoting cytokine that is also implicated in colon tumorigenesis. We propose that IL-22 increases MASTL protein stability by promoting its association with CAIX potentially via AKT signaling to promote cell survival and proliferation.
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Affiliation(s)
- Kristina Pravoverov
- Eppley Institute, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Iram Fatima
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Susmita Barman
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Frank Jühling
- Inserm U1110, Université de Strasbourg, Institute for Translational Medicine and Liver Disease (ITM), Strasbourg, France
- Inserm U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Université de Strasbourg, Strasbourg, France
| | - Mark Primeaux
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Thomas F Baumert
- Inserm U1110, Université de Strasbourg, Institute for Translational Medicine and Liver Disease (ITM), Strasbourg, France
- Inserm U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Université de Strasbourg, Strasbourg, France
- IHU Strasbourg and Gastroenterology-Hepatology Service, Strasbourg University Hospitals, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
| | - Amar B Singh
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States
- Veteran Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska, United States
| | - Punita Dhawan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States
- Veteran Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska, United States
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2
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Gao X, Johnson WE, Yourick MR, Campasino K, Sprando RL, Yourick JJ. Hepatotoxicity of silver nanoparticles: Benchmark concentration modeling of an in vitro transcriptomics study in human iPSC-derived hepatocytes. Regul Toxicol Pharmacol 2024; 151:105653. [PMID: 38825064 DOI: 10.1016/j.yrtph.2024.105653] [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: 12/13/2023] [Revised: 05/21/2024] [Accepted: 05/30/2024] [Indexed: 06/04/2024]
Abstract
Despite two decades of research on silver nanoparticle (AgNP) toxicity, a safe threshold for exposure has not yet been established, albeit being critically needed for risk assessment and regulatory decision-making. Traditionally, a point-of-departure (PoD) value is derived from dose response of apical endpoints in animal studies using either the no-observed-adverse-effect level (NOAEL) approach, or benchmark dose (BMD) modeling. To develop new approach methodologies (NAMs) to inform human risk assessment of AgNPs, we conducted a concentration response modeling of the transcriptomic changes in hepatocytes derived from human induced pluripotent stem cells (iPSCs) after being exposed to a wide range concentration (0.01-25 μg/ml) of AgNPs for 24 h. A plausible transcriptomic PoD of 0.21 μg/ml was derived for a pathway related to the mode-of-action (MOA) of AgNPs, and a more conservative PoD of 0.10 μg/ml for a gene ontology (GO) term not apparently associated with the MOA of AgNPs. A reference dose (RfD) could be calculated from either of the PoDs as a safe threshold for AgNP exposure. The current study illustrates the usefulness of in vitro transcriptomic concentration response study using human cells as a NAM for toxicity study of chemicals that lack adequate toxicity data to inform human risk assessment.
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Affiliation(s)
- Xiugong Gao
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, USA.
| | - W Evan Johnson
- Division of Infectious Disease, Center for Data Science, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Miranda R Yourick
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, USA
| | - Kayla Campasino
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, USA
| | - Robert L Sprando
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, USA
| | - Jeffrey J Yourick
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, USA
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3
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Misra G, Rajawat J, Pal R, Smith JC, Kumar A. Targeted inhibition of MASTL kinase activity induces apoptosis in breast cancer. Life Sci 2023; 334:122250. [PMID: 37931742 DOI: 10.1016/j.lfs.2023.122250] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/20/2023] [Accepted: 11/03/2023] [Indexed: 11/08/2023]
Abstract
Microtubule-associated serine/threonine kinase-like (MASTL) (or Greatwall kinase (GWL)) is an important cell cycle regulating kinase that regulates the G2-M transition. Uncontrolled MASTL activity is implicated in breast cancer progression. To date, very few inhibitors have been reported against this protein. Here, structure-based computational modeling indicates that the natural product flavopiridol (FLV) binds strongly to MASTL and these results are validated using molecular dynamics simulation studies. An in vitro kinase assay reveals an EC50 (effective concentration) value of FLV to be 82.1 nM and a better IC50 compared to the positive reference compound, staurosporine. FLV is found to inhibit MASTL kinase activity, arresting the cell growth in the G1 phase and inducing apoptosis in breast cancer cells. Consistent with these results differential gene expression obtained using RNA sequencing studies, and validated by RT PCR and immunoblot analysis, indicate that MASTL inhibition induces cell cycle arrest and apoptotic-related genes. Furthermore, metastasis- and inflammation-related genes are downregulated. Thus, the deregulation of MASTL signaling pathways on targeted inhibition of its kinase activity is revealed. This study lays a strong foundation for investigating FLV as a lead compound in breast cancer therapeutics.
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Affiliation(s)
- Gauri Misra
- National Institute of Biologicals (Ministry of Health and Family Welfare, Government of India), Noida 201309, India.
| | - Jyotika Rajawat
- Institute of Advanced Molecular Genetics & Infectious Diseases, ONGC, Centre for Advanced Studies, University of Lucknow, Lucknow 226 007, UP, India
| | - Rajesh Pal
- Precision Sarcoma Research Group, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Jeremy C Smith
- Oak Ridge National Laboratory, Biosciences Division, UT/ORNL Center for Molecular Biophysics, Oak Ridge, TN, USA; Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Amit Kumar
- Department of Electrical and Electronic Engineering, University of Cagliari, Via Marengo 2, 09123 Cagliari, Italy
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4
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Erguven M, Kilic S, Karaca E, Diril MK. Genetic complementation screening and molecular docking give new insight on phosphorylation-dependent Mastl kinase activation. J Biomol Struct Dyn 2023; 41:8241-8253. [PMID: 36270968 DOI: 10.1080/07391102.2022.2131627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/26/2022] [Indexed: 10/24/2022]
Abstract
Mastl is a mitotic kinase that is essential for error-free chromosome segregation. It is an atypical member of AGC kinase family, possessing a unique non-conserved middle region. The mechanism of Mastl activation has been studied extensively in vitro. Phosphorylation of several residues were identified to be crucial for activation. These sites correspond to T193 and T206 in the activation loop and S861 in the C-terminal tail of mouse Mastl. To date, the significance of these phosphosites was not confirmed in intact mammalian cells. Here, we utilize a genetic complementation approach to determine the essentials of mammalian Mastl kinase activation. We used tamoxifen-inducible conditional knockout mouse embryonic fibroblasts to delete endogenous Mastl and screened various mutants for their ability to complement its loss. S861A mutant was able to complement endogenous Mastl loss. In parallel, we performed computational molecular docking studies to evaluate the significance of this residue for kinase activation. Our in-depth sequence and structure analysis revealed that Mastl pS861 does not belong to a conformational state, where the phosphoresidue contributes to C-tail docking. C-tail of Mastl is relatively short and it lacks a hydrophobic (HF) motif that would otherwise help its anchoring over N-lobe, required for the final steps of kinase activation. Our results show that phosphorylation of Mastl C-tail turn motif (S861) is dispensable for kinase function in cellulo.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Mehmet Erguven
- Izmir Biomedicine and Genome Center, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Izmir, Turkey
| | - Seval Kilic
- Izmir Biomedicine and Genome Center, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Izmir, Turkey
| | - Ezgi Karaca
- Izmir Biomedicine and Genome Center, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Izmir, Turkey
| | - M Kasim Diril
- Izmir Biomedicine and Genome Center, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Izmir, Turkey
- Department of Medical Biology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
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5
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Emond-Fraser V, Larouche M, Kubiniok P, Bonneil É, Li J, Bourouh M, Frizzi L, Thibault P, Archambault V. Identification of PP2A-B55 targets uncovers regulation of emerin during nuclear envelope reassembly in Drosophila. Open Biol 2023; 13:230104. [PMID: 37463656 PMCID: PMC10353892 DOI: 10.1098/rsob.230104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/21/2023] [Indexed: 07/20/2023] Open
Abstract
Mitotic exit requires the dephosphorylation of many proteins whose phosphorylation was needed for mitosis. Protein phosphatase 2A with its B55 regulatory subunit (PP2A-B55) promotes this transition. However, the events and substrates that it regulates are incompletely understood. We used proteomic approaches in Drosophila to identify proteins that interact with and are dephosphorylated by PP2A-B55. Among several candidates, we identified emerin (otefin in Drosophila). Emerin resides in the inner nuclear membrane and interacts with the DNA-binding protein barrier-to-autointegration factor (BAF) via a LEM domain. We found that the phosphorylation of emerin at Ser50 and Ser54 near its LEM domain negatively regulates its association with BAF, lamin and additional emerin in mitosis. We show that dephosphorylation of emerin at these sites by PP2A-B55 determines the timing of nuclear envelope reformation. Genetic experiments indicate that this regulation is required during embryonic development. Phosphoregulation of the emerin-BAF complex formation by PP2A-B55 appears as a key event of mitotic exit that is likely conserved across species.
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Affiliation(s)
- Virginie Emond-Fraser
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Peter Kubiniok
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Éric Bonneil
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Jingjing Li
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Mohammed Bourouh
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Laura Frizzi
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de chimie, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
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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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Iliaki S, Beyaert R, Afonina IS. Polo-like kinase 1 (PLK1) signaling in cancer and beyond. Biochem Pharmacol 2021; 193:114747. [PMID: 34454931 DOI: 10.1016/j.bcp.2021.114747] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 02/07/2023]
Abstract
PLK1 is an evolutionary conserved Ser/Thr kinase that is best known for its role in cell cycle regulation and is expressed predominantly during the G2/S and M phase of the cell cycle. PLK1-mediated phosphorylation of specific substrates controls cell entry into mitosis, centrosome maturation, spindle assembly, sister chromatid cohesion and cytokinesis. In addition, a growing body of evidence describes additional roles of PLK1 beyond the cell cycle, more specifically in the DNA damage response, autophagy, apoptosis and cytokine signaling. PLK1 has an indisputable role in cancer as it controls several key transcription factors and promotes cell proliferation, transformation and epithelial-to-mesenchymal transition. Furthermore, deregulation of PLK1 results in chromosome instability and aneuploidy. PLK1 is overexpressed in many cancers, which is associated with poor prognosis, making PLK1 an attractive target for cancer treatment. Additionally, PLK1 is involved in immune and neurological disorders including Graft versus Host Disease, Huntington's disease and Alzheimer's disease. Unfortunately, newly developed small compound PLK1 inhibitors have only had limited success so far, due to low therapeutic response rates and toxicity. In this review we will highlight the current knowledge about the established roles of PLK1 in mitosis regulation and beyond. In addition, we will discuss its tumor promoting but also tumor suppressing capacities, as well as the available PLK1 inhibitors, elaborating on their efficacy and limitations.
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Affiliation(s)
- Styliani Iliaki
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, B-9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Rudi Beyaert
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, B-9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, B-9052 Ghent, Belgium.
| | - Inna S Afonina
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, B-9052 Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, B-9052 Ghent, Belgium
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8
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Discovery and Characterization of a Novel MASTL Inhibitor MKI-2 Targeting MASTL-PP2A in Breast Cancer Cells and Oocytes. Pharmaceuticals (Basel) 2021; 14:ph14070647. [PMID: 34358073 PMCID: PMC8308786 DOI: 10.3390/ph14070647] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 11/20/2022] Open
Abstract
Although microtubule-associated serine/threonine kinase-like (MASTL) is a promising target for selective anticancer treatment, MASTL inhibitors with nano range potency and antitumor efficacy have not been reported. Here, we report a novel potent and selective MASTL inhibitor MASTL kinase inhibitor-2 (MKI-2) identified in silico through a drug discovery program. Our data showed that MKI-2 inhibited recombinant MASTL activity and cellular MASTL activity with IC50 values of 37.44 nM and 142.7 nM, respectively, in breast cancer cells. In addition, MKI-2 inhibited MASTL kinase rather than other AGC kinases, such as ROCK1, AKT1, PKACα, and p70S6K. Furthermore, MKI-2 exerted various antitumor activities by inducing mitotic catastrophe resulting from the modulation of the MASTL-PP2A axis in breast cancer cells. The MKI-2 treatment showed phenocopies with MASTL-null oocyte in mouse oocytes, which were used as a model to validate MKI-2 activity. Therefore, our study provided a new potent and selective MASTL inhibitor MKI-2 targeting the oncogenic MAST-PP2A axis in breast cancer cells.
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9
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Argunhan B, Iwasaki H, Tsubouchi H. Post-translational modification of factors involved in homologous recombination. DNA Repair (Amst) 2021; 104:103114. [PMID: 34111757 DOI: 10.1016/j.dnarep.2021.103114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 02/04/2023]
Abstract
DNA is the molecule that stores the chemical instructions necessary for life and its stability is therefore of the utmost importance. Despite this, DNA is damaged by both exogenous and endogenous factors at an alarming frequency. The most severe type of DNA damage is a double-strand break (DSB), in which a scission occurs in both strands of the double helix, effectively dividing a single normal chromosome into two pathological chromosomes. Homologous recombination (HR) is a universal DSB repair mechanism that solves this problem by identifying another region of the genome that shares high sequence similarity with the DSB site and using it as a template for repair. Rad51 possess the enzymatic activity that is essential for this repair but several auxiliary factors are required for Rad51 to fulfil its function. It is becoming increasingly clear that many HR factors are subjected to post-translational modification. Here, we review what is known about how these modifications affect HR. We first focus on cases where there is experimental evidence to support a function for the modification, then discuss speculative cases where a function can be inferred. Finally, we contemplate why such modifications might be necessary.
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Affiliation(s)
- Bilge Argunhan
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan.
| | - Hiroshi Iwasaki
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Hideo Tsubouchi
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
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10
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Larouche M, Kachaner D, Wang P, Normandin K, Garrido D, Yao C, Cormier M, Johansen KM, Johansen J, Archambault V. Spatiotemporal coordination of Greatwall-Endos-PP2A promotes mitotic progression. J Cell Biol 2021; 220:211965. [PMID: 33836042 PMCID: PMC8042607 DOI: 10.1083/jcb.202008145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 02/17/2021] [Accepted: 03/08/2021] [Indexed: 12/31/2022] Open
Abstract
Mitotic entry involves inhibition of protein phosphatase 2A bound to its B55/Tws regulatory subunit (PP2A-B55/Tws), which dephosphorylates substrates of mitotic kinases. This inhibition is induced when Greatwall phosphorylates Endos, turning it into an inhibitor of PP2A-Tws. How this mechanism operates spatiotemporally in the cell is incompletely understood. We previously reported that the nuclear export of Greatwall in prophase promotes mitotic progression. Here, we examine the importance of the localized activities of PP2A-Tws and Endos for mitotic regulation. We find that Tws shuttles through the nucleus via a conserved nuclear localization signal (NLS), but expression of Tws in the cytoplasm and not in the nucleus rescues the development of tws mutants. Moreover, we show that Endos must be in the cytoplasm before nuclear envelope breakdown (NEBD) to be efficiently phosphorylated by Greatwall and to bind and inhibit PP2A-Tws. Disrupting the cytoplasmic function of Endos before NEBD results in subsequent mitotic defects. Evidence suggests that this spatiotemporal regulation is conserved in humans.
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Affiliation(s)
- Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - David Kachaner
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Peng Wang
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Karine Normandin
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada
| | - Damien Garrido
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Changfu Yao
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA
| | - Maxime Cormier
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada
| | - Kristen M Johansen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA
| | - Jørgen Johansen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
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