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Delisle SV, Labreche C, Lara-Márquez M, Abou-Hamad J, Garland B, Lamarche-Vane N, Sabourin LA. Expression of a kinase inactive SLK is embryonic lethal and impairs cell migration in fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119783. [PMID: 38871226 DOI: 10.1016/j.bbamcr.2024.119783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 06/03/2024] [Accepted: 06/06/2024] [Indexed: 06/15/2024]
Abstract
Kinases are known to have kinase activity independent functions. To gain further insights into potential kinase-independent functions of SLK/STK2, we have developed a kinase-dead allele, SLKK63R using in vivo CRISPR/Cas technology. Our studies show that blastocysts homozygote for SLKK63R do not develop into viable mice. However, heterozygotes are viable and fertile with no overt phenotypes. Analyses of mouse embryonic fibroblasts show that expression of SLKK63R results in a 50% decrease in kinase activity in heterozygotes. In contrast to previous studies, our data show that SLK does not form homodimers and that the kinase defective allele does not act in a dominant negative fashion. Expression of SLKK63R leads to altered Rac1 and RhoA activity, increased stress fiber formation and delayed focal adhesion turnover. Our data support a previously observed role for SLK in cell migration and suggest that at least 50% kinase activity is sufficient for embryonic development.
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Affiliation(s)
- Samuel V Delisle
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Cedrik Labreche
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Mónica Lara-Márquez
- Cancer Research Program, Research Institute of the McGill University Health Centre and Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - John Abou-Hamad
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada; Dept. of Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Brennan Garland
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Nathalie Lamarche-Vane
- Cancer Research Program, Research Institute of the McGill University Health Centre and Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Luc A Sabourin
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada; Dept. of Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
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2
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Li AX, Martin TA, Lane J, Jiang WG. Cellular Impacts of Striatins and the STRIPAK Complex and Their Roles in the Development and Metastasis in Clinical Cancers (Review). Cancers (Basel) 2023; 16:76. [PMID: 38201504 PMCID: PMC10777921 DOI: 10.3390/cancers16010076] [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: 11/23/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
Striatins (STRNs) are generally considered to be cytoplasmic proteins, with lower expression observed in the nucleus and at cell-cell contact regions. Together with protein phosphatase 2A (PP2A), STRNs form the core region of striatin-interacting phosphatase and kinase (STRIPAK) complexes through the coiled-coil region of STRN proteins, which is crucial for substrate recruitment. Over the past two decades, there has been an increasing amount of research into the biological and cellular functions of STRIPAK members. STRNs and the constituent members of the STRIPAK complex have been found to regulate several cellular functions, such as cell cycle control, cell growth, and motility. Dysregulation of these cellular events is associated with cancer development. Importantly, their roles in cancer cells and clinical cancers are becoming recognised, with several STRIPAK components found to have elevated expression in cancerous tissues compared to healthy tissues. These molecules exhibit significant diagnostic and prognostic value across different cancer types and in metastatic progression. The present review comprehensively summarises and discusses the current knowledge of STRNs and core STRIPAK members, in cancer malignancy, from both cellular and clinical perspectives.
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Affiliation(s)
| | - Tracey A. Martin
- Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK; (A.X.L.); (J.L.); (W.G.J.)
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3
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Li C, Zhu X, Sun X, Guo X, Li W, Chen P, Shidlovskii YV, Zhou Q, Xue L. Slik maintains tissue homeostasis by preventing JNK-mediated apoptosis. Cell Div 2023; 18:16. [PMID: 37794497 PMCID: PMC10552427 DOI: 10.1186/s13008-023-00097-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 09/11/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND The c-Jun N-terminal kinase (JNK) pathway is an evolutionarily conserved regulator of cell death, which is essential for coordinating tissue homeostasis. In this study, we have characterized the Drosophila Ste20-like kinase Slik as a novel modulator of JNK pathway-mediated apoptotic cell death. RESULTS First, ectopic JNK signaling-triggered cell death is enhanced by slik depletion whereas suppressed by Slik overexpression. Second, loss of slik activates JNK signaling, which results in enhanced apoptosis and impaired tissue homeostasis. In addition, genetic epistasis analysis suggests that Slik acts upstream of or in parallel to Hep to regulate JNK-mediated apoptotic cell death. Moreover, Slik is necessary and sufficient for preventing physiologic JNK signaling-mediated cell death in development. Furthermore, introduction of STK10, the human ortholog of Slik, into Drosophila restores slik depletion-induced cell death and compromised tissue homeostasis. Lastly, knockdown of STK10 in human cancer cells also leads to JNK activation, which is cancelled by expression of Slik. CONCLUSIONS This study has uncovered an evolutionarily conserved role of Slik/STK10 in blocking JNK signaling, which is required for cell death inhibition and tissue homeostasis maintenance in development.
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Affiliation(s)
- Chenglin Li
- The First Rehabilitation Hospital of Shanghai, Shanghai Key Laboratory of Signaling and Diseases Research, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xiaojie Zhu
- The First Rehabilitation Hospital of Shanghai, Shanghai Key Laboratory of Signaling and Diseases Research, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xinyue Sun
- The First Rehabilitation Hospital of Shanghai, Shanghai Key Laboratory of Signaling and Diseases Research, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xiaowei Guo
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Wenzhe Li
- The First Rehabilitation Hospital of Shanghai, Shanghai Key Laboratory of Signaling and Diseases Research, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Ping Chen
- The First Rehabilitation Hospital of Shanghai, Shanghai Key Laboratory of Signaling and Diseases Research, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Yulii V Shidlovskii
- Department of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- Department of Biology and General Genetics, Sechenov University, 8, bldg. 2 Trubetskaya St, Moscow, 119048, Russia
| | - Qian Zhou
- The First Rehabilitation Hospital of Shanghai, Shanghai Key Laboratory of Signaling and Diseases Research, School of Life Science and Technology, Tongji University, Shanghai, China.
| | - Lei Xue
- The First Rehabilitation Hospital of Shanghai, Shanghai Key Laboratory of Signaling and Diseases Research, School of Life Science and Technology, Tongji University, Shanghai, China.
- Guangdong Provincial Key Laboratory of Tumor Interventional Diagnosis and Treatment, Zhuhai Precision Medical Center, Zhuhai People's Hospital, Zhuhai Hospital Affiliated with Jinan University, Zhuhai, Guangdong, China.
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4
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Song K, Jiang X, Xu X, Chen Y, Zhang J, Tian Y, Wang Q, Weng J, Liang Y, Ma W. Ste20-like kinase activity promotes meiotic resumption and spindle microtubule stability in mouse oocytes. Cell Prolif 2022; 56:e13391. [PMID: 36579845 PMCID: PMC10068952 DOI: 10.1111/cpr.13391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/30/2022] Open
Abstract
Ste20-like kinase (SLK) is involved in cell proliferation and migration in somatic cells. This study aims to explore SLK expression and function in mouse oocyte meiosis. Western blot, immunofluorescence, Co-immunoprecipitation, drug treatment, cRNA construct and in vitro transcription, microinjection of morpholino oilgo (MO) and cRNA were performed in oocytes. High and stable protein expression of SLK was detected in mouse oocyte meiosis, with dynamic distribution in the nucleus, chromosomes and spindle apparatus. SLK phosphorylation emerges around meiotic resumption and reaches a peak during metaphase I (MI) and metaphase II. SLK knockdown with MO or expression of kinase-dead SLK K63R dramatically delays meiotic resumption due to sequentially suppressed phosphorylation of Polo-like kinase 1 (Plk1) and cell division cycle 25C (CDC25C) and dephosphorylation of cyclin-dependent kinase 1 (CDK1). SLK depletion promotes ubiquitination-mediated degradation of paxillin, an antagonist to α-tubulin deacetylation, and thus destroys spindle assembly and chromosome alignment; these phenotypes can be substantially rescued by exogenous expression of SLK kinase active fragment. Additionally, exogenous SLK effectively promotes meiotic progression and spindle assembly in aging oocytes with reduced SLK. Collectively, this study reveals SLK is required for meiotic resumption and spindle assembly in mouse oocyte meiosis.
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Affiliation(s)
- Ke Song
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xiuying Jiang
- Division of Sport Anatomy, School of Sport Science, Beijing Sport University, Beijing, China
| | - Xiangning Xu
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Ye Chen
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Jiaqi Zhang
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Ying Tian
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Qian Wang
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Jing Weng
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yuanjing Liang
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wei Ma
- Department of Histology and Embryology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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5
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Garland B, Delisle S, Al-Zahrani KN, Pryce BR, Sabourin LA. The Ste20-like kinase - a Jack of all trades? J Cell Sci 2021; 134:261804. [PMID: 33961052 DOI: 10.1242/jcs.258269] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Over the past 20 years, the Ste20-like kinase (SLK; also known as STK2) has emerged as a central regulator of cytoskeletal dynamics. Reorganization of the cytoskeleton is necessary for a plethora of biological processes including apoptosis, proliferation, migration, tissue repair and signaling. Several studies have also uncovered a role for SLK in disease progression and cancer. Here, we review the recent findings in the SLK field and summarize the various roles of SLK in different animal models and discuss the biochemical mechanisms regulating SLK activity. Together, these studies have revealed multiple roles for SLK in coupling cytoskeletal dynamics to cell growth, in muscle repair and in negative-feedback loops critical for cancer progression. Furthermore, the ability of SLK to regulate some systems appears to be kinase activity independent, suggesting that it may be an important scaffold for signal transduction pathways. These various findings reveal highly complex functions and regulation patterns of SLK in development and disease, making it a potential therapeutic target.
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Affiliation(s)
- Brennan Garland
- Ottawa Hospital Research Institute, Cancer Therapeutics, Ottawa, Ontario, K1H8L1, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, K1H8L6, Canada
| | - Samuel Delisle
- Ottawa Hospital Research Institute, Cancer Therapeutics, Ottawa, Ontario, K1H8L1, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, K1H8L6, Canada
| | - Khalid N Al-Zahrani
- Center for Molecular and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G1X5, Canada
| | - Benjamin R Pryce
- Department of Pediatrics, Hollings Cancer Center, Medical University of South Carolina,Charleston, SC 29425, USA
| | - Luc A Sabourin
- Ottawa Hospital Research Institute, Cancer Therapeutics, Ottawa, Ontario, K1H8L1, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, K1H8L6, Canada
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6
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De Jamblinne CV, Decelle B, Dehghani M, Joseph M, Sriskandarajah N, Leguay K, Rambaud B, Lemieux S, Roux PP, Hipfner DR, Carréno S. STRIPAK regulates Slik localization to control mitotic morphogenesis and epithelial integrity. J Cell Biol 2021; 219:152107. [PMID: 32960945 PMCID: PMC7594492 DOI: 10.1083/jcb.201911035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 07/17/2020] [Accepted: 08/20/2020] [Indexed: 02/01/2023] Open
Abstract
Proteins of the ezrin, radixin, and moesin (ERM) family control cell and tissue morphogenesis. We previously reported that moesin, the only ERM in Drosophila, controls mitotic morphogenesis and epithelial integrity. We also found that the Pp1-87B phosphatase dephosphorylates moesin, counteracting its activation by the Ste20-like kinase Slik. To understand how this signaling pathway is itself regulated, we conducted a genome-wide RNAi screen, looking for new regulators of moesin activity. We identified that Slik is a new member of the striatin-interacting phosphatase and kinase complex (STRIPAK). We discovered that the phosphatase activity of STRIPAK reduces Slik phosphorylation to promote its cortical association and proper activation of moesin. Consistent with this finding, inhibition of STRIPAK phosphatase activity causes cell morphology defects in mitosis and impairs epithelial tissue integrity. Our results implicate the Slik–STRIPAK complex in the control of multiple morphogenetic processes.
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Affiliation(s)
- Camille Valérie De Jamblinne
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Barbara Decelle
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Mehrnoush Dehghani
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Mathieu Joseph
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Neera Sriskandarajah
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Kévin Leguay
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Basile Rambaud
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Sébastien Lemieux
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Département de Biochimie, Université de Montréal, Montréal, Quebec, Canada
| | - Philippe P Roux
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada
| | - David R Hipfner
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Médecine, Université de Montréal, Montréal, Quebec, Canada
| | - Sébastien Carréno
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada
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7
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Bagci H, Sriskandarajah N, Robert A, Boulais J, Elkholi IE, Tran V, Lin ZY, Thibault MP, Dubé N, Faubert D, Hipfner DR, Gingras AC, Côté JF. Mapping the proximity interaction network of the Rho-family GTPases reveals signalling pathways and regulatory mechanisms. Nat Cell Biol 2019; 22:120-134. [DOI: 10.1038/s41556-019-0438-7] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 11/19/2019] [Indexed: 12/17/2022]
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8
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Ahiri A, Garmes H, Podlipnik C, Aboulmouhajir A. Insights into evolutionary interaction patterns of the 'Phosphorylation Activation Segment' in kinase. Bioinformation 2019; 15:666-677. [PMID: 31787816 PMCID: PMC6859708 DOI: 10.6026/97320630015666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 10/07/2019] [Accepted: 10/09/2019] [Indexed: 12/17/2022] Open
Abstract
We are interested in studying the phosphorylation of the kinase activation loop, distinguishing the passage from the unphosphorylated to the phosphorylated form without allostery. We performed an interaction study to trace the change of interactions between the activation segment and the kinase catalytic core, before and after phosphorylation. Results show that the structural changes are mainly due to the attraction between the phosphate group and guanidine groups of the arginine side chains of RD-pocket, which are constituted mainly of guanidine groups of the catalytic loop, the β9, and the αC helix. This attraction causes propagation of structural variation of the activation segment, principally towards the N-terminal. The structural variations are not made on all the amino acids of the activation segment; they are conditioned by the existence of two beta sheets stabilizing the loop during phosphorylation. The first,β6-β9 sheet is usually present in most of the kinases; the second, β10-β11 is formed due to the interaction between the main chain amino acids of the activation loop and the αEF/αF loop.
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Affiliation(s)
- Adil Ahiri
- Modeling and Molecular Spectroscopy Team, Faculty of Sciences, University Chouaib Doukkali, El-Jadida, Morroco
| | - Hocine Garmes
- Analytical Chemistry and Environmental Sciences Team, Department of chemistry, Faculty of Science, University Chouaib Doukkali, El Jadida, Morroco
| | - Crtomir Podlipnik
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Aziz Aboulmouhajir
- Modeling and Molecular Spectroscopy Team, Faculty of Sciences, University Chouaib Doukkali, El-Jadida, Morroco
- Extraction, Spectroscopy and Valorization Team, Organic synthesis, Extraction and Valorization Laboratory, Faculty of Sciences of Ain Chock, Hassan II University, Casablanca, Morocco
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9
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Katzemich A, Long JY, Panneton V, Fisher LAB, Hipfner D, Schöck F. Slik phosphorylation of Talin T152 is crucial for proper Talin recruitment and maintenance of muscle attachment in Drosophila. Development 2019; 146:dev.176339. [PMID: 31511253 DOI: 10.1242/dev.176339] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 09/04/2019] [Indexed: 01/12/2023]
Abstract
Talin is the major scaffold protein linking integrin receptors with the actin cytoskeleton. In Drosophila, extended Talin generates a stable link between the sarcomeric cytoskeleton and the tendon matrix at muscle attachment sites. Here, we identify phosphorylation sites on Drosophila Talin by mass spectrometry. Talin is phosphorylated in late embryogenesis when muscles differentiate, especially on T152 in the exposed loop of the F1 domain of the Talin head. Localization of a mutated version of Talin (Talin-T150/T152A) is reduced at muscle attachment sites and can only partially rescue muscle attachment compared with wild-type Talin. We also identify Slik as the kinase phosphorylating Talin at T152. Slik localizes to muscle attachment sites, and the absence of Slik reduces the localization of Talin at muscle attachment sites causing phenotypes similar to Talin-T150/T152A. Thus, our results demonstrate that Talin phosphorylation by Slik plays an important role in fine-tuning Talin recruitment to integrin adhesion sites and maintaining muscle attachment.
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Affiliation(s)
- Anja Katzemich
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, Quebec H3A 1B1, Canada
| | - Jenny Yanyan Long
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, Quebec H3A 1B1, Canada
| | - Vincent Panneton
- Institut de Recherches Cliniques de Montréal, Québec H2W 1R7, Canada.,Département de Médecine, Université de Montréal, Québec H3C 3J7, Canada
| | - Lucas A B Fisher
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, Quebec H3A 1B1, Canada
| | - David Hipfner
- Institut de Recherches Cliniques de Montréal, Québec H2W 1R7, Canada.,Département de Médecine, Université de Montréal, Québec H3C 3J7, Canada
| | - Frieder Schöck
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, Quebec H3A 1B1, Canada
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10
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Abeysundara N, Simmonds AJ, Hughes SC. Moesin is involved in polarity maintenance and cortical remodeling during asymmetric cell division. Mol Biol Cell 2018; 29:419-434. [PMID: 29282284 PMCID: PMC6014166 DOI: 10.1091/mbc.e17-05-0294] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 12/08/2017] [Accepted: 12/13/2017] [Indexed: 01/17/2023] Open
Abstract
An intact actomyosin network is essential for anchoring polarity proteins to the cell cortex and maintaining cell size asymmetry during asymmetric cell division of Drosophila neuroblasts (NBs). However, the mechanisms that control changes in actomyosin dynamics during asymmetric cell division remain unclear. We find that the actin-binding protein, Moesin, is essential for NB proliferation and mitotic progression in the developing brain. During metaphase, phosphorylated Moesin (p-Moesin) is enriched at the apical cortex, and loss of Moesin leads to defects in apical polarity maintenance and cortical stability. This asymmetric distribution of p-Moesin is determined by components of the apical polarity complex and Slik kinase. During later stages of mitosis, p-Moesin localization shifts more basally, contributing to asymmetric cortical extension and myosin basal furrow positioning. Our findings reveal Moesin as a novel apical polarity protein that drives cortical remodeling of dividing NBs, which is essential for polarity maintenance and initial establishment of cell size asymmetry.
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Affiliation(s)
- Namal Abeysundara
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Andrew J Simmonds
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Sarah C Hughes
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
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11
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Cybulsky AV, Guillemette J, Papillon J, Abouelazm NT. Regulation of Ste20-like kinase, SLK, activity: Dimerization and activation segment phosphorylation. PLoS One 2017; 12:e0177226. [PMID: 28475647 PMCID: PMC5419656 DOI: 10.1371/journal.pone.0177226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/24/2017] [Indexed: 12/11/2022] Open
Abstract
The Ste20-like kinase, SLK, has diverse cellular functions. SLK mediates organ development, cell cycle progression, cytoskeletal remodeling, cytokinesis, and cell survival. Expression and activity of SLK are enhanced in renal ischemia-reperfusion injury, and overexpression of SLK was shown to induce apoptosis in cultured glomerular epithelial cells (GECs) and renal tubular cells, as well as GEC/podocyte injury in vivo. The SLK protein consists of a N-terminal catalytic domain and an extensive C-terminal domain, which contains coiled-coils. The present study addresses the regulation of SLK activity. Controlled dimerization of the SLK catalytic domain enhanced autophosphorylation of SLK at T183 and S189, which are located in the activation segment. The full-length ectopically- and endogenously-expressed SLK was also autophosphorylated at T183 and S189. Using ezrin as a model SLK substrate (to address exogenous kinase activity), we demonstrate that dimerized SLK 1–373 or full-length SLK can effectively induce activation-specific phosphorylation of ezrin. Mutations in SLK, including T183A, S189A or T193A reduced T183 or S189 autophosphorylation, and showed a greater reduction in ezrin phosphorylation. Mutations in the coiled-coil region of full-length SLK that impair dimerization, in particular I848G, significantly reduced ezrin phosphorylation and tended to reduce autophosphorylation of SLK at T183. In experimental membranous nephropathy in rats, proteinuria and GEC/podocyte injury were associated with increased glomerular SLK activity and ezrin phosphorylation. In conclusion, dimerization via coiled-coils and phosphorylation of T183, S189 and T193 play key roles in the activation and signaling of SLK, and provide targets for novel therapeutic approaches.
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Affiliation(s)
- Andrey V. Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
- * E-mail:
| | - Julie Guillemette
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Joan Papillon
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Nihad T. Abouelazm
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
- Department of Clinical Pharmacology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
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