1
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Li X, Zheng J, Su J, Wang L, Luan L, Wang T, Bai F, Zhong Q, Gong Q. Myotubularin 2 interacts with SEC23A and negatively regulates autophagy at ER exit sites in Arabidopsis. Autophagy 2024:1-19. [PMID: 39177202 DOI: 10.1080/15548627.2024.2394302] [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: 04/17/2024] [Revised: 08/11/2024] [Accepted: 08/15/2024] [Indexed: 08/24/2024] Open
Abstract
Starvation- or stress-induced phosphatidylinositol 3-phosphate (PtdIns3P/PI3P) production at the endoplasmic reticulum (ER) subdomains organizes phagophore assembly and autophagosome formation. Coat protein complex II (COPII) vesicles budding from ER exit site (ERES) also contribute to autophagosome formation. Whether any PtdIns3P phosphatase functions at ERES to inhibit macroautophagy/autophagy is unknown. Here we report Myotubularin 2 (MTM2) of Arabidopsis as a PtdIns3P phosphatase that localizes to ERES and negatively regulates autophagy. MTM2 binds PtdIns3P with its PH-GRAM domain in vitro and acts toward PtdIns3P in vivo. Transiently expressed MTM2 colocalizes with ATG14b, a subunit of the phosphatidylinositol 3-kinase (PtdIns3K) complex, and overexpression of MTM2 blocks autophagic flux and causes over-accumulation of ATG18a, ATG5, and ATG8a. The mtm2 mutant has higher levels of autophagy and is more tolerant to starvation, whereas MTM2 overexpression leads to reduced autophagy and sensitivity to starvation. The phenotypes of mtm2 are suppressed by ATG2 mutation, suggesting that MTM2 acts upstream of ATG2. Importantly, MTM2 does not affect the endosomal functions of PtdIns3P. Instead, MTM2 specifically colocalizes with COPII coat proteins and is cradled by the ERES-defining protein SEC16. MTM2 interacts with SEC23A with its phosphatase domain and inhibits COPII-mediated protein secretion. Finally, a role for MTM2 in salt stress response is uncovered. mtm2 resembles the halophyte Thellungiella salsuginea in its efficient vacuolar compartmentation of Na+, maintenance of chloroplast integrity, and timely regulation of autophagy-related genes. Our findings reveal a balance between PtdIns3P synthesis and turnover in autophagosome formation, and provide a new link between autophagy and COPII function.Abbreviations: ATG: autophagy related; BFA: brefeldin A; BiFC: bimolecular fluorescence complementation; CHX: cycloheximide; ConA: concanamycin A; COPII: coat protein complex II; ER: endoplasmic reticulum; ERES: ER exit site; MS: Murashige and Skoog; MTM: myotubularin; MVB: multivesicular body; PAS: phagophore assembly site; PI: phosphoinositide; TEM: transmission electron microscopy; WT: wild-type.
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Affiliation(s)
- Xinjing Li
- State Key Laboratory of Microbial Metabolism & Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China
| | - Jing Zheng
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, P. R. China
| | - Jing Su
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, P. R. China
| | - Lin Wang
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, P. R. China
| | - Lin Luan
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, P. R. China
| | - Taotao Wang
- State Key Laboratory of Microbial Metabolism & Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China
| | - Fang Bai
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, P. R. China
| | - Qing Zhong
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, P. R. China
| | - Qingqiu Gong
- State Key Laboratory of Microbial Metabolism & Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China
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2
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Briand-Mésange F, Gennero I, Salles J, Trudel S, Dahan L, Ausseil J, Payrastre B, Salles JP, Chap H. From Classical to Alternative Pathways of 2-Arachidonoylglycerol Synthesis: AlterAGs at the Crossroad of Endocannabinoid and Lysophospholipid Signaling. Molecules 2024; 29:3694. [PMID: 39125098 PMCID: PMC11314389 DOI: 10.3390/molecules29153694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 07/27/2024] [Accepted: 08/02/2024] [Indexed: 08/12/2024] Open
Abstract
2-arachidonoylglycerol (2-AG) is the most abundant endocannabinoid (EC), acting as a full agonist at both CB1 and CB2 cannabinoid receptors. It is synthesized on demand in postsynaptic membranes through the sequential action of phosphoinositide-specific phospholipase Cβ1 (PLCβ1) and diacylglycerol lipase α (DAGLα), contributing to retrograde signaling upon interaction with presynaptic CB1. However, 2-AG production might also involve various combinations of PLC and DAGL isoforms, as well as additional intracellular pathways implying other enzymes and substrates. Three other alternative pathways of 2-AG synthesis rest on the extracellular cleavage of 2-arachidonoyl-lysophospholipids by three different hydrolases: glycerophosphodiesterase 3 (GDE3), lipid phosphate phosphatases (LPPs), and two members of ecto-nucleotide pyrophosphatase/phosphodiesterases (ENPP6-7). We propose the names of AlterAG-1, -2, and -3 for three pathways sharing an ectocellular localization, allowing them to convert extracellular lysophospholipid mediators into 2-AG, thus inducing typical signaling switches between various G-protein-coupled receptors (GPCRs). This implies the critical importance of the regioisomerism of both lysophospholipid (LPLs) and 2-AG, which is the object of deep analysis within this review. The precise functional roles of AlterAGs are still poorly understood and will require gene invalidation approaches, knowing that both 2-AG and its related lysophospholipids are involved in numerous aspects of physiology and pathology, including cancer, inflammation, immune defenses, obesity, bone development, neurodegeneration, or psychiatric disorders.
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Affiliation(s)
- Fabienne Briand-Mésange
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
| | - Isabelle Gennero
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Biochimie, Institut Fédératif de Biologie, 31059 Toulouse, France
| | - Juliette Salles
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Psychiatrie D’urgences, de Crise et de Liaison, Institut des Handicaps Neurologiques, Psychiatriques et Sensoriels, 31059 Toulouse, France
| | - Stéphanie Trudel
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Biochimie, Institut Fédératif de Biologie, 31059 Toulouse, France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France;
| | - Jérôme Ausseil
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Biochimie, Institut Fédératif de Biologie, 31059 Toulouse, France
| | - Bernard Payrastre
- I2MC-Institute of Metabolic and Cardiovascular Diseases, INSERM UMR1297 and University of Toulouse III, 31400 Toulouse, France;
- Centre Hospitalier Universitaire de Toulouse, Laboratoire d’Hématologie, 31400 Toulouse, France
| | - Jean-Pierre Salles
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Unité d’Endocrinologie et Maladies Osseuses, Hôpital des Enfants, 31059 Toulouse, France
| | - Hugues Chap
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Académie des Sciences, Inscriptions et Belles Lettres de Toulouse, Hôtel d’Assézat, 31000 Toulouse, France
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3
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Fuentes R, Marlow FL, Abrams EW, Zhang H, Kobayashi M, Gupta T, Kapp LD, DiNardo Z, Heller R, Cisternas R, García-Castro P, Segovia-Miranda F, Montecinos-Franjola F, Vought W, Vejnar CE, Giraldez AJ, Mullins MC. Maternal regulation of the vertebrate oocyte-to-embryo transition. PLoS Genet 2024; 20:e1011343. [PMID: 39052672 DOI: 10.1371/journal.pgen.1011343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 08/06/2024] [Accepted: 06/13/2024] [Indexed: 07/27/2024] Open
Abstract
Maternally-loaded factors in the egg accumulate during oogenesis and are essential for the acquisition of oocyte and egg developmental competence to ensure the production of viable embryos. However, their molecular nature and functional importance remain poorly understood. Here, we present a collection of 9 recessive maternal-effect mutants identified in a zebrafish forward genetic screen that reveal unique molecular insights into the mechanisms controlling the vertebrate oocyte-to-embryo transition. Four genes, over easy, p33bjta, poached and black caviar, were found to control initial steps in yolk globule sizing and protein cleavage during oocyte maturation that act independently of nuclear maturation. The krang, kazukuram, p28tabj, and spotty genes play distinct roles in egg activation, including cortical granule biology, cytoplasmic segregation, the regulation of microtubule organizing center assembly and microtubule nucleation, and establishing the basic body plan. Furthermore, we cloned two of the mutant genes, identifying the over easy gene as a subunit of the Adaptor Protein complex 5, Ap5m1, which implicates it in regulating intracellular trafficking and yolk vesicle formation. The novel maternal protein Krang/Kiaa0513, highly conserved in metazoans, was discovered and linked to the function of cortical granules during egg activation. These mutant genes represent novel genetic entry points to decipher the molecular mechanisms functioning in the oocyte-to-embryo transition, fertility, and human disease. Additionally, our genetic adult screen not only contributes to the existing knowledge in the field but also sets the basis for future investigations. Thus, the identified maternal genes represent key players in the coordination and execution of events prior to fertilization.
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Affiliation(s)
- Ricardo Fuentes
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Florence L Marlow
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine Mount Sinai, New York, New York, United States of America
| | - Elliott W Abrams
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Biology, Purchase College, State University of New York, Purchase, New York, United States of America
| | - Hong Zhang
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Manami Kobayashi
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Tripti Gupta
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lee D Kapp
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Zachary DiNardo
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Ronald Heller
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Ruth Cisternas
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Priscila García-Castro
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Fabián Segovia-Miranda
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Felipe Montecinos-Franjola
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, Maryland, United States of America
| | - William Vought
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Charles E Vejnar
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Antonio J Giraldez
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
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4
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Dai N, Groenendyk J, Michalak M. Interplay between myotubularins and Ca 2+ homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119739. [PMID: 38710289 DOI: 10.1016/j.bbamcr.2024.119739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/08/2024]
Abstract
The myotubularin family, encompassing myotubularin 1 (MTM1) and 14 myotubularin-related proteins (MTMRs), represents a conserved group of phosphatases featuring a protein tyrosine phosphatase domain. Nine members are characterized by an active phosphatase domain C(X)5R, dephosphorylating the D3 position of PtdIns(3)P and PtdIns(3,5)P2. Mutations in myotubularin genes result in human myopathies, and several neuropathies including X-linked myotubular myopathy and Charcot-Marie-Tooth type 4B. MTM1, MTMR6 and MTMR14 also contribute to Ca2+ signaling and Ca2+ homeostasis that play a key role in many MTM-dependent myopathies and neuropathies. Here we explore the evolving roles of MTM1/MTMRs, unveiling their influence on critical aspects of Ca2+ signaling pathways.
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Affiliation(s)
- Ning Dai
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Jody Groenendyk
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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5
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Wang J, Guo W, Wang Q, Yang Y, Sun X. Recent advances of myotubularin-related (MTMR) protein family in cardiovascular diseases. Front Cardiovasc Med 2024; 11:1364604. [PMID: 38529329 PMCID: PMC10961392 DOI: 10.3389/fcvm.2024.1364604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 02/27/2024] [Indexed: 03/27/2024] Open
Abstract
Belonging to a lipid phosphatase family containing 16 members, myotubularin-related proteins (MTMRs) are widely expressed in a variety of tissues and organs. MTMRs preferentially hydrolyzes phosphatidylinositol 3-monophosphate and phosphatidylinositol (3,5) bis-phosphate to generate phosphatidylinositol and phosphatidylinositol 5-monophosphate, respectively. These phosphoinositides (PIPs) promote membrane degradation during autophagosome-lysosomal fusion and are also involved in various regulatory signal transduction. Based on the ability of modulating the levels of these PIPs, MTMRs exert physiological functions such as vesicle trafficking, cell proliferation, differentiation, necrosis, cytoskeleton, and cell migration. It has recently been found that MTMRs are also involved in the occurrence and development of several cardiovascular diseases, including cardiomyocyte hypertrophy, proliferation of vascular smooth muscle cell, LQT1, aortic aneurysm, etc. This review summarizes the functions of MTMRs and highlights their pathophysiological roles in cardiovascular diseases.
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Affiliation(s)
- Jia Wang
- Department of Cardiology, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
- College of Medicine, Southwest Jiaotong University, Chengdu, Sichuan, China
| | - Wei Guo
- Clinical Research Center, Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Qiang Wang
- Department of Cardiology, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
- College of Medicine, Southwest Jiaotong University, Chengdu, Sichuan, China
| | - Yongjian Yang
- Department of Cardiology, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Xiongshan Sun
- Department of Cardiology, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
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6
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Liu D, Zhang Y, Fang H, Yuan J, Ji L. The progress of research into pseudophosphatases. Front Public Health 2022; 10:965631. [PMID: 36106167 PMCID: PMC9464862 DOI: 10.3389/fpubh.2022.965631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/09/2022] [Indexed: 01/24/2023] Open
Abstract
Pseudophosphatases are a class of phosphatases that mutate at the catalytically active site. They play important parts in many life processes and disorders, e.g., cell apoptosis, stress reaction, tumorigenesis, axon differentiation, Charcot-Marie-Tooth, and metabolic dysfunction. The present review considers the structures and action types of pseudophosphatases in four families, protein tyrosine phosphatases (PTPs), myotube protein phosphatases (MTMs), phosphatases and tensin homologues (PTENs) and dual specificity phosphatases (DUSPs), as well as their mechanisms in signaling and disease. We aimed to provide reference material for the research and treatment of related diseases.
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Affiliation(s)
- Deqiang Liu
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Yiming Zhang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Hui Fang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jinxiang Yuan
- College of Life Sciences, Shandong Normal University, Jinan, China,The Collaborative Innovation Center, Jining Medical University, Jining, China,*Correspondence: Jinxiang Yuan
| | - Lizhen Ji
- College of Life Sciences, Shandong Normal University, Jinan, China,Lizhen Ji
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7
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Ceyhan Y, Zhang M, Sandoval CG, Agoulnik AI, Agoulnik IU. Expression pattern and the roles of phosphatidylinositol phosphatases in testis. Biol Reprod 2022; 107:902-915. [PMID: 35766372 DOI: 10.1093/biolre/ioac132] [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: 03/23/2022] [Revised: 06/02/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphoinositides (PIs) are relatively rare lipid components of the cellular membranes. Their homeostasis is tightly controlled by specific PI kinases and phosphatases. PIs play essential roles in cellular signaling, cytoskeletal organization, and secretory processes in various diseases and normal physiology. Gene targeting experiments strongly suggest that in mice with deficiency of several PI phosphatases such as Pten, Mtmrs, Inpp4b, and Inpp5b, spermatogenesis is affected, resulting in partial or complete infertility. Similarly, in men, loss of several of the PIP phosphatases is observed in infertility characterized by the lack of mature sperm. Using available gene expression databases, we compare expression of known PI phosphatases in various testicular cell types, infertility patients, and mouse age-dependent testicular gene expression, and discuss their potential roles in testis physiology and spermatogenesis.
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Affiliation(s)
- Yasemin Ceyhan
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Manqi Zhang
- Department of Medicine, Duke University, Durham, NC, USA
| | - Carlos G Sandoval
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,New York University Grossman School of Medicine, New York, NY, USA
| | - Alexander I Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Irina U Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
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8
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Autophagy: Identification of MTMR5 as a neuron-enriched suppressor. Curr Biol 2022; 32:R574-R577. [PMID: 35728530 PMCID: PMC9994184 DOI: 10.1016/j.cub.2022.04.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A puzzle of autophagy in neurons is that, unlike in other cells, it is not robustly induced by inhibition of mammalian target of rapamycin (mTOR). A new study now solves this conundrum and establishes that myotubularin-related phosphatase 5 limits the induction of neuronal autophagy by mTOR inhibitors.
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9
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Chua JP, Bedi K, Paulsen MT, Ljungman M, Tank EMH, Kim ES, McBride JP, Colón-Mercado JM, Ward ME, Weisman LS, Barmada SJ. Myotubularin-related phosphatase 5 is a critical determinant of autophagy in neurons. Curr Biol 2022; 32:2581-2595.e6. [PMID: 35580604 PMCID: PMC9233098 DOI: 10.1016/j.cub.2022.04.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 02/18/2022] [Accepted: 04/20/2022] [Indexed: 12/12/2022]
Abstract
Autophagy is a conserved, multi-step process of capturing proteolytic cargo in autophagosomes for lysosome degradation. The capacity to remove toxic proteins that accumulate in neurodegenerative disorders attests to the disease-modifying potential of the autophagy pathway. However, neurons respond only marginally to conventional methods for inducing autophagy, limiting efforts to develop therapeutic autophagy modulators for neurodegenerative diseases. The determinants underlying poor autophagy induction in neurons and the degree to which neurons and other cell types are differentially sensitive to autophagy stimuli are incompletely defined. Accordingly, we sampled nascent transcript synthesis and stabilities in fibroblasts, induced pluripotent stem cells (iPSCs), and iPSC-derived neurons (iNeurons), thereby uncovering a neuron-specific stability of transcripts encoding myotubularin-related phosphatase 5 (MTMR5). MTMR5 is an autophagy suppressor that acts with its binding partner, MTMR2, to dephosphorylate phosphoinositides critical for autophagy initiation and autophagosome maturation. We found that MTMR5 is necessary and sufficient to suppress autophagy in iNeurons and undifferentiated iPSCs. Using optical pulse labeling to visualize the turnover of endogenously encoded proteins in live cells, we observed that knockdown of MTMR5 or MTMR2, but not the unrelated phosphatase MTMR9, significantly enhances neuronal degradation of TDP-43, an autophagy substrate implicated in several neurodegenerative diseases. Our findings thus establish a regulatory mechanism of autophagy intrinsic to neurons and targetable for clearing disease-related proteins in a cell-type-specific manner. In so doing, our results not only unravel novel aspects of neuronal biology and proteostasis but also elucidate a strategy for modulating neuronal autophagy that could be of high therapeutic potential for multiple neurodegenerative diseases.
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Affiliation(s)
- Jason P. Chua
- Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Lead contact
| | - Karan Bedi
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Michelle T. Paulsen
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center and Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI, USA
| | - Mats Ljungman
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center and Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI, USA
| | | | - Erin S. Kim
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Jonathon P. McBride
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Michael E. Ward
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Lois S. Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Sami J. Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
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10
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Mammel AE, Delgado KC, Chin AL, Condon AF, Hill JQ, Aicher SA, Wang Y, Fedorov LM, Robinson FL. Distinct roles for the Charcot-Marie-tooth disease-causing endosomal regulators Mtmr5 and Mtmr13 in axon radial sorting and Schwann cell myelination. Hum Mol Genet 2021; 31:1216-1229. [PMID: 34718573 DOI: 10.1093/hmg/ddab311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 09/29/2021] [Accepted: 10/19/2021] [Indexed: 11/12/2022] Open
Abstract
The form of Charcot-Marie-Tooth type 4B (CMT4B) disease caused by mutations in myotubularin-related 5 (MTMR5; also called SET Binding Factor 1; SBF1) shows a spectrum of axonal and demyelinating nerve phenotypes. This contrasts with the CMT4B subtypes caused by MTMR2 or MTMR13 (SBF2) mutations, which are characterized by myelin outfoldings and classic demyelination. Thus, it is unclear whether MTMR5 plays an analogous or distinct role from that of its homolog, MTMR13, in the peripheral nervous system (PNS). MTMR5 and MTMR13 are pseudophosphatases predicted to regulate endosomal trafficking by activating Rab GTPases and binding to the phosphoinositide 3-phosphatase MTMR2. In the mouse PNS, Mtmr2 was required to maintain wild type levels of Mtmr5 and Mtmr13, suggesting that these factors function in discrete protein complexes. Genetic elimination of both Mtmr5 and Mtmr13 in mice led to perinatal lethality, indicating that the two proteins have partially redundant functions during embryogenesis. Loss of Mtmr5 in mice did not cause CMT4B-like myelin outfoldings. However, adult Mtmr5-/- mouse nerves contained fewer myelinated axons than control nerves, likely as a result of axon radial sorting defects. Consistently, Mtmr5 levels were highest during axon radial sorting and fell sharply after postnatal day seven. Our findings suggest that Mtmr5 and Mtmr13 ensure proper axon radial sorting and Schwann cell myelination, respectively, perhaps through their direct interactions with Mtmr2. This study enhances our understanding of the non-redundant roles of the endosomal regulators MTMR5 and MTMR13 during normal peripheral nerve development and disease.
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Affiliation(s)
- Anna E Mammel
- The Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.,Cell, Developmental & Cancer Biology Graduate Program, Oregon Health & Science University
| | - Katherine C Delgado
- The Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Andrea L Chin
- The Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Alec F Condon
- The Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.,Neuroscience Graduate Program, Oregon Health & Science University
| | - Jo Q Hill
- Department of Physiology and Pharmacology, Oregon Health & Science University
| | - Sue A Aicher
- Department of Physiology and Pharmacology, Oregon Health & Science University
| | - Yingming Wang
- OHSU Transgenic Mouse Models Shared Resource, Knight Cancer Institute, Oregon Health & Science University
| | - Lev M Fedorov
- OHSU Transgenic Mouse Models Shared Resource, Knight Cancer Institute, Oregon Health & Science University
| | - Fred L Robinson
- The Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.,Vollum Institute, Oregon Health & Science University
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11
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Markworth R, Bähr M, Burk K. Held Up in Traffic-Defects in the Trafficking Machinery in Charcot-Marie-Tooth Disease. Front Mol Neurosci 2021; 14:695294. [PMID: 34483837 PMCID: PMC8415527 DOI: 10.3389/fnmol.2021.695294] [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: 04/14/2021] [Accepted: 07/23/2021] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT), also known as motor and sensory neuropathy, describes a clinically and genetically heterogenous group of disorders affecting the peripheral nervous system. CMT typically arises in early adulthood and is manifested by progressive loss of motor and sensory functions; however, the mechanisms leading to the pathogenesis are not fully understood. In this review, we discuss disrupted intracellular transport as a common denominator in the pathogenesis of different CMT subtypes. Intracellular transport via the endosomal system is essential for the delivery of lipids, proteins, and organelles bidirectionally to synapses and the soma. As neurons of the peripheral nervous system are amongst the longest neurons in the human body, they are particularly susceptible to damage of the intracellular transport system, leading to a loss in axonal integrity and neuronal death. Interestingly, defects in intracellular transport, both in neurons and Schwann cells, have been found to provoke disease. This review explains the mechanisms of trafficking and subsequently summarizes and discusses the latest findings on how defects in trafficking lead to CMT. A deeper understanding of intracellular trafficking defects in CMT will expand our understanding of CMT pathogenesis and will provide novel approaches for therapeutic treatments.
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Affiliation(s)
- Ronja Markworth
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Katja Burk
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
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12
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Aromolaran O, Beder T, Adedeji E, Ajamma Y, Oyelade J, Adebiyi E, Koenig R. Predicting host dependency factors of pathogens in Drosophila melanogaster using machine learning. Comput Struct Biotechnol J 2021; 19:4581-4592. [PMID: 34471501 PMCID: PMC8385402 DOI: 10.1016/j.csbj.2021.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/06/2021] [Accepted: 08/06/2021] [Indexed: 11/25/2022] Open
Abstract
Pathogens causing infections, and particularly when invading the host cells, require the host cell machinery for efficient regeneration and proliferation during infection. For their life cycle, host proteins are needed and these Host Dependency Factors (HDF) may serve as therapeutic targets. Several attempts have approached screening for HDF producing large lists of potential HDF with, however, only marginal overlap. To get consistency into the data of these experimental studies, we developed a machine learning pipeline. As a case study, we used publicly available lists of experimentally derived HDF from twelve different screening studies based on gene perturbation in Drosophila melanogaster cells or in vivo upon bacterial or protozoan infection. A total of 50,334 gene features were generated from diverse categories including their functional annotations, topology attributes in protein interaction networks, nucleotide and protein sequence features, homology properties and subcellular localization. Cross-validation revealed an excellent prediction performance. All feature categories contributed to the model. Predicted and experimentally derived HDF showed a good consistency when investigating their common cellular processes and function. Cellular processes and molecular function of these genes were highly enriched in membrane trafficking, particularly in the trans-Golgi network, cell cycle and the Rab GTPase binding family. Using our machine learning approach, we show that HDF in organisms can be predicted with high accuracy evidencing their common investigated characteristics. We elucidated cellular processes which are utilized by invading pathogens during infection. Finally, we provide a list of 208 novel HDF proposed for future experimental studies.
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Affiliation(s)
- Olufemi Aromolaran
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Thomas Beder
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Eunice Adedeji
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
- Department of Biochemistry, Covenant University, Ota, Ogun State, Nigeria
| | - Yvonne Ajamma
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Jelili Oyelade
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Ezekiel Adebiyi
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Rainer Koenig
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
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13
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Mattei AM, Smailys JD, Hepworth EMW, Hinton SD. The Roles of Pseudophosphatases in Disease. Int J Mol Sci 2021; 22:ijms22136924. [PMID: 34203203 PMCID: PMC8269279 DOI: 10.3390/ijms22136924] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/10/2021] [Accepted: 06/24/2021] [Indexed: 01/07/2023] Open
Abstract
The pseudophosphatases, atypical members of the protein tyrosine phosphatase family, have emerged as bona fide signaling regulators within the past two decades. Their roles as regulators have led to a renaissance of the pseudophosphatase and pseudoenyme fields, catapulting interest from a mere curiosity to intriguing and relevant proteins to investigate. Pseudophosphatases make up approximately fourteen percent of the phosphatase family, and are conserved throughout evolution. Pseudophosphatases, along with pseudokinases, are important players in physiology and pathophysiology. These atypical members of the protein tyrosine phosphatase and protein tyrosine kinase superfamily, respectively, are rendered catalytically inactive through mutations within their catalytic active signature motif and/or other important domains required for catalysis. This new interest in the pursuit of the relevant functions of these proteins has resulted in an elucidation of their roles in signaling cascades and diseases. There is a rapid accumulation of knowledge of diseases linked to their dysregulation, such as neuropathies and various cancers. This review analyzes the involvement of pseudophosphatases in diseases, highlighting the function of various role(s) of pseudophosphatases involvement in pathologies, and thus providing a platform to strongly consider them as key therapeutic drug targets.
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14
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Reiterer V, Pawłowski K, Desrochers G, Pause A, Sharpe HJ, Farhan H. The dead phosphatases society: a review of the emerging roles of pseudophosphatases. FEBS J 2020; 287:4198-4220. [PMID: 32484316 DOI: 10.1111/febs.15431] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/12/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022]
Abstract
Phosphatases are a diverse family of enzymes, comprising at least 10 distinct protein folds. Like most other enzyme families, many have sequence variations that predict an impairment or loss of catalytic activity classifying them as pseudophosphatases. Research on pseudoenzymes is an emerging area of interest, with new biological functions repurposed from catalytically active relatives. Here, we provide an overview of the pseudophosphatases identified to date in all major phosphatase families. We will highlight the degeneration of the various catalytic sequence motifs and discuss the challenges associated with the experimental determination of catalytic inactivity. We will also summarize the role of pseudophosphatases in various diseases and discuss the major challenges and future directions in this field.
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Affiliation(s)
| | | | - Guillaume Desrochers
- Department of Biochemistry, McGill University, Montréal, QC, Canada.,Goodman Cancer Research Centre, McGill University, Montréal, QC, Canada
| | - Arnim Pause
- Department of Biochemistry, McGill University, Montréal, QC, Canada.,Goodman Cancer Research Centre, McGill University, Montréal, QC, Canada
| | | | - Hesso Farhan
- Institute of Basic Medical Sciences, University of Oslo, Norway
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15
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Myotubularin-related protein 7 activates peroxisome proliferator-activated receptor-gamma. Oncogenesis 2020; 9:59. [PMID: 32522977 PMCID: PMC7286916 DOI: 10.1038/s41389-020-0238-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/15/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023] Open
Abstract
Peroxisome proliferator-activated receptor-gamma (PPARγ) is a transcription factor drugable by agonists approved for treatment of type 2 diabetes, but also inhibits carcinogenesis and cell proliferation in vivo. Activating mutations in the Kirsten rat sarcoma viral oncogene homologue (KRAS) gene mitigate these beneficial effects by promoting a negative feedback-loop comprising extracellular signal-regulated kinase 1/2 (ERK1/2) and mitogen-activated kinase kinase 1/2 (MEK1/2)-dependent inactivation of PPARγ. To overcome this inhibitory mechanism, we searched for novel post-translational regulators of PPARγ. Phosphoinositide phosphatase Myotubularin-Related-Protein-7 (MTMR7) was identified as cytosolic interaction partner of PPARγ. Synthetic peptides were designed resembling the regulatory coiled-coil (CC) domain of MTMR7, and their activities studied in human cancer cell lines and C57BL6/J mice. MTMR7 formed a complex with PPARγ and increased its transcriptional activity by inhibiting ERK1/2-dependent phosphorylation of PPARγ. MTMR7-CC peptides mimicked PPARγ-activation in vitro and in vivo due to LXXLL motifs in the CC domain. Molecular dynamics simulations and docking predicted that peptides interact with the steroid receptor coactivator 1 (SRC1)-binding site of PPARγ. Thus, MTMR7 is a positive regulator of PPARγ, and its mimicry by synthetic peptides overcomes inhibitory mechanisms active in cancer cells possibly contributing to the failure of clinical studies targeting PPARγ.
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16
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Bellio M, Caux M, Vauclard A, Chicanne G, Gratacap MP, Terrisse AD, Severin S, Payrastre B. Phosphatidylinositol 3 monophosphate metabolizing enzymes in blood platelet production and in thrombosis. Adv Biol Regul 2019; 75:100664. [PMID: 31604685 DOI: 10.1016/j.jbior.2019.100664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/19/2019] [Accepted: 09/30/2019] [Indexed: 02/09/2023]
Abstract
Blood platelets, produced by the fragmentation of megakaryocytes, play a key role in hemostasis and thrombosis. Being implicated in atherothrombosis and other thromboembolic disorders, they represent a major therapeutic target for antithrombotic drug development. Several recent studies have highlighted an important role for the lipid phosphatidylinositol 3 monophosphate (PtdIns3P) in megakaryocytes and platelets. PtdIns3P, present in small amounts in mammalian cells, is involved in the control of endocytic trafficking and autophagy. Its metabolism is finely regulated by specific kinases and phosphatases. Class II (α, β and γ) and III (Vps34) phosphoinositide-3-kinases (PI3Ks), INPP4 and Fig4 are involved in the production of PtdIns3P whereas PIKFyve, myotubularins (MTMs) and type II PIPK metabolize PtdIns3P. By regulating the turnover of different pools of PtdIns3P, class II (PI3KC2α) and class III (Vps34) PI3Ks have been recently involved in the regulation of platelet production and functions. These pools of PtdIns3P appear to modulate membrane organization and intracellular trafficking. Moreover, PIKFyve and INPP4 have been recently implicated in arterial thrombosis. In this review, we will discuss the role of PtdIns3P metabolizing enzymes in platelet production and function. Potential new anti-thrombotic therapeutic perspectives based on inhibitors targeting specifically PtdIns3P metabolizing enzymes will also be commented.
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Affiliation(s)
- Marie Bellio
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Manuella Caux
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Alicia Vauclard
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Gaëtan Chicanne
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Marie-Pierre Gratacap
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Anne-Dominique Terrisse
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Sonia Severin
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Bernard Payrastre
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France; Laboratoire d'Hématologie, Hopital Universitaire de Toulouse, Toulouse, France.
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17
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Volpatti JR, Al-Maawali A, Smith L, Al-Hashim A, Brill JA, Dowling JJ. The expanding spectrum of neurological disorders of phosphoinositide metabolism. Dis Model Mech 2019; 12:12/8/dmm038174. [PMID: 31413155 PMCID: PMC6737944 DOI: 10.1242/dmm.038174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositides (PIPs) are a ubiquitous group of seven low-abundance phospholipids that play a crucial role in defining localized membrane properties and that regulate myriad cellular processes, including cytoskeletal remodeling, cell signaling cascades, ion channel activity and membrane traffic. PIP homeostasis is tightly regulated by numerous inositol kinases and phosphatases, which phosphorylate and dephosphorylate distinct PIP species. The importance of these phospholipids, and of the enzymes that regulate them, is increasingly being recognized, with the identification of human neurological disorders that are caused by mutations in PIP-modulating enzymes. Genetic disorders of PIP metabolism include forms of epilepsy, neurodegenerative disease, brain malformation syndromes, peripheral neuropathy and congenital myopathy. In this Review, we provide an overview of PIP function and regulation, delineate the disorders associated with mutations in genes that modulate or utilize PIPs, and discuss what is understood about gene function and disease pathogenesis as established through animal models of these diseases. Summary: This Review highlights the intersection between phosphoinositides and the enzymes that regulate their metabolism, which together are crucial regulators of myriad cellular processes and neurological disorders.
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Affiliation(s)
- Jonathan R Volpatti
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Almundher Al-Maawali
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Lindsay Smith
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Aqeela Al-Hashim
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Neuroscience, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Julie A Brill
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - James J Dowling
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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18
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Robinson DC, Mammel AE, Logan AM, Larson AA, Schmidt EJ, Condon AF, Robinson FL. An In Vitro Model of Charcot-Marie-Tooth Disease Type 4B2 Provides Insight Into the Roles of MTMR13 and MTMR2 in Schwann Cell Myelination. ASN Neuro 2019; 10:1759091418803282. [PMID: 30419760 PMCID: PMC6236487 DOI: 10.1177/1759091418803282] [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] [Indexed: 01/16/2023] Open
Abstract
Charcot-Marie-Tooth Disorder Type 4B (CMT4B) is a demyelinating
peripheral neuropathy caused by mutations in myotubularin-related
(MTMR) proteins 2, 13, or 5 (CMT4B1/2/3), which regulate
phosphoinositide turnover and endosomal trafficking. Although mouse
models of CMT4B2 exist, an in vitro model would make
possible pharmacological and reverse genetic experiments needed to
clarify the role of MTMR13 in myelination. We have generated such a
model using Schwann cell-dorsal root ganglion (SC-DRG) explants from
Mtmr13−/− mice. Myelin sheaths
in mutant cultures contain outfoldings highly reminiscent of those
observed in the nerves of Mtmr13−/− mice
and CMT4B2 patients. Mtmr13−/− SC-DRG
explants also contain reduced Mtmr2, further supporting a role of
Mtmr13 in stabilizing Mtmr2. Elevated PI(3,5)P2 has been
implicated as a cause of myelin outfoldings in
Mtmr2−/− models. In contrast,
the role of elevated PI3P or PI(3,5)P2 in promoting
outfoldings in Mtmr13−/− models is
unclear. We found that over-expression of MTMR2 in
Mtmr13−/− SC-DRGs moderately
reduced the prevalence of myelin outfoldings. Thus, a manipulation
predicted to lower PI3P and PI(3,5)P2 partially suppressed
the phenotype caused by Mtmr13 deficiency. We also explored the
relationship between CMT4B2-like myelin outfoldings and kinases that
produce PI3P and PI(3,5)P2 by analyzing nerve pathology in
mice lacking both Mtmr13 and one of two specific PI 3-kinases.
Intriguingly, the loss of vacuolar protein sorting 34 or PI3K-C2β in
Mtmr13−/− mice had no impact
on the prevalence of myelin outfoldings. In aggregate, our findings
suggest that the MTMR13 scaffold protein likely has critical functions
other than stabilizing MTMR2 to achieve an adequate level of PI
3-phosphatase activity.
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Affiliation(s)
- Danielle C Robinson
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,2 Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Anna E Mammel
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,3 Cell, Developmental & Cancer Biology Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Anne M Logan
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,2 Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Aubree A Larson
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA
| | - Eric J Schmidt
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA
| | - Alec F Condon
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,2 Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Fred L Robinson
- 1 Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.,4 Vollum Institute, Oregon Health & Science University, Portland, OR, USA
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19
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Nakada-Tsukui K, Watanabe N, Maehama T, Nozaki T. Phosphatidylinositol Kinases and Phosphatases in Entamoeba histolytica. Front Cell Infect Microbiol 2019; 9:150. [PMID: 31245297 PMCID: PMC6563779 DOI: 10.3389/fcimb.2019.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. In the enteric protozoan parasite Entamoeba histolytica, it has been previously shown that the PIs phosphatidylinositol 3-phosphate (PtdIns3P), PtdIns(4,5)P2, and PtdIns(3,4,5)P3 are localized to phagosomes/phagocytic cups, plasma membrane, and phagocytic cups, respectively. The localization of these PIs in E. histolytica is similar to that in mammalian cells, suggesting that PIs have orthologous functions in E. histolytica. In contrast, the conservation of the enzymes that metabolize PIs in this organism has not been well-documented. In this review, we summarized the full repertoire of the PI kinases and PI phosphatases found in E. histolytica via a genome-wide survey of the current genomic information. E. histolytica appears to have 10 PI kinases and 23 PI phosphatases. It has a panel of evolutionarily conserved enzymes that generate all the seven PI species. However, class II PI 3-kinases, type II PI 4-kinases, type III PI 5-phosphatases, and PI 4P-specific phosphatases are not present. Additionally, regulatory subunits of class I PI 3-kinases and type III PI 4-kinases have not been identified. Instead, homologs of class I PI 3-kinases and PTEN, a PI 3-phosphatase, exist as multiple isoforms, which likely reflects that elaborate signaling cascades mediated by PtdIns(3,4,5)P3 are present in this organism. There are several enzymes that have the nuclear localization signal: one phosphatidylinositol phosphate (PIP) kinase, two PI 3-phosphatases, and one PI 5-phosphatase; this suggests that PI metabolism also has conserved roles related to nuclear functions in E. histolytica, as it does in model organisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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20
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Pareyson D, Stojkovic T, Reilly MM, Leonard-Louis S, Laurà M, Blake J, Parman Y, Battaloglu E, Tazir M, Bellatache M, Bonello-Palot N, Lévy N, Sacconi S, Guimarães-Costa R, Attarian S, Latour P, Solé G, Megarbane A, Horvath R, Ricci G, Choi BO, Schenone A, Gemelli C, Geroldi A, Sabatelli M, Luigetti M, Santoro L, Manganelli F, Quattrone A, Valentino P, Murakami T, Scherer SS, Dankwa L, Shy ME, Bacon CJ, Herrmann DN, Zambon A, Tramacere I, Pisciotta C, Magri S, Previtali SC, Bolino A. A multicenter retrospective study of charcot-marie-tooth disease type 4B (CMT4B) associated with mutations in myotubularin-related proteins (MTMRs). Ann Neurol 2019; 86:55-67. [PMID: 31070812 DOI: 10.1002/ana.25500] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 04/23/2019] [Accepted: 05/05/2019] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Charcot-Marie-Tooth (CMT) disease 4B1 and 4B2 (CMT4B1/B2) are characterized by recessive inheritance, early onset, severe course, slowed nerve conduction, and myelin outfoldings. CMT4B3 shows a more heterogeneous phenotype. All are associated with myotubularin-related protein (MTMR) mutations. We conducted a multicenter, retrospective study to better characterize CMT4B. METHODS We collected clinical and genetic data from CMT4B subjects in 18 centers using a predefined minimal data set including Medical Research Council (MRC) scores of nine muscle pairs and CMT Neuropathy Score. RESULTS There were 50 patients, 21 of whom never reported before, carrying 44 mutations, of which 21 were novel and six representing novel disease associations of known rare variants. CMT4B1 patients had significantly more-severe disease than CMT4B2, with earlier onset, more-frequent motor milestones delay, wheelchair use, and respiratory involvement as well as worse MRC scores and motor CMT Examination Score components despite younger age at examination. Vocal cord involvement was common in both subtypes, whereas glaucoma occurred in CMT4B2 only. Nerve conduction velocities were similarly slowed in both subtypes. Regression analyses showed that disease severity is significantly associated with age in CMT4B1. Slopes are steeper for CMT4B1, indicating faster disease progression. Almost none of the mutations in the MTMR2 and MTMR13 genes, responsible for CMT4B1 and B2, respectively, influence the correlation between disease severity and age, in agreement with the hypothesis of a complete loss of function of MTMR2/13 proteins for such mutations. INTERPRETATION This is the largest CMT4B series ever reported, demonstrating that CMT4B1 is significantly more severe than CMT4B2, and allowing an estimate of prognosis. ANN NEUROL 2019.
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Affiliation(s)
- Davide Pareyson
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Tanya Stojkovic
- Hôpital Pitié-Salpêtrière, AP-HP, Centre de référence des maladies neuromusculaires Nord/Est/Ile de France, Paris, France
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Sarah Leonard-Louis
- Hôpital Pitié-Salpêtrière, AP-HP, Centre de référence des maladies neuromusculaires Nord/Est/Ile de France, Paris, France
| | - Matilde Laurà
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Julian Blake
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom.,Department of Clinical Neurophysiology, Norfolk and Norwich University Hospital, Norfolk, United Kingdom
| | - Yesim Parman
- Istanbul University, Istanbul Faculty of Medicine, Neurology Dep. Istanbul, Turkey
| | - Esra Battaloglu
- Bogazici University, Department of Molecular Biology and Genetics, Istanbul, Turkey
| | - Meriem Tazir
- Laboratoire de Recherche en Neurosciences Service de Neurologie, CHU, Alger, Algeria
| | - Mounia Bellatache
- Laboratoire de Recherche en Neurosciences Service de Neurologie, CHU, Alger, Algeria
| | - Nathalie Bonello-Palot
- Department of Medical Genetics, Timone Hospital, Marseille, France.2, Aix-Marseille University, INSERM, MMG, U1251, Marseille, France
| | - Nicolas Lévy
- Department of Medical Genetics, Timone Hospital, Marseille, France.2, Aix-Marseille University, INSERM, MMG, U1251, Marseille, France
| | - Sabrina Sacconi
- Université Côte d'Azur, Service Système Nerveux Périphérique, Muscle et SLA, Centre Hospitalier Universitaire de Nice, Nice, France
| | - Raquel Guimarães-Costa
- Hôpital Pitié-Salpêtrière, AP-HP, Centre de référence des maladies neuromusculaires Nord/Est/Ile de France, Paris, France
| | - Sharham Attarian
- Reference center for neuromuscular disorders and ALS, CHU La Timone, Aix-Marseille University, Marseille, France
| | - Philippe Latour
- Center of Biology and Pathology Laboratory of Molecular Neurogenetics, Hospices Civils, Lyon, France
| | - Guilhem Solé
- Reference center for neuromuscular disorders AOC (Atlantique Occitanie Caraibes), CHU de Bordeaux, Bordeaux, France
| | - André Megarbane
- Institut Jérôme Lejeune, Paris, France.,INOVIE, Beirut, Lebanon
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Institute of Genetic Medicine, Newcastle University, Newcastle, United Kingdom
| | - Giulia Ricci
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Angelo Schenone
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and MATERNAL Infantile Sciences, University of Genoa, and IRCCS Policlinico San Martino, Genoa, Italy
| | - Chiara Gemelli
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and MATERNAL Infantile Sciences, University of Genoa, and IRCCS Policlinico San Martino, Genoa, Italy
| | - Alessandro Geroldi
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and MATERNAL Infantile Sciences, University of Genoa, and IRCCS Policlinico San Martino, Genoa, Italy
| | - Mario Sabatelli
- Fondazione Policlinico Universitario Agostino Gemelli IRCCS. Centro Clinico Nemo Adulti Rome, Rome, Italy.,Università Cattolica del Sacro Cuore. Sede di Roma, Rome, Italy
| | - Marco Luigetti
- Università Cattolica del Sacro Cuore. Sede di Roma, Rome, Italy.,UOC Neurologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Lucio Santoro
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
| | - Aldo Quattrone
- Department of Neurology, Università Magna Graecia di Catanzaro, Catanzaro, Italy
| | - Paola Valentino
- Department of Neurology, Università Magna Graecia di Catanzaro, Catanzaro, Italy
| | | | - Steven S Scherer
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Lois Dankwa
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Michael E Shy
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA
| | - Chelsea J Bacon
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA
| | | | - Alberto Zambon
- Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Irene Tramacere
- Department of Research and Clinical Development, Scientific Directorate, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chiara Pisciotta
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stefania Magri
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stefano C Previtali
- Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Alessandra Bolino
- Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
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21
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Identification of Key Signaling Pathways Orchestrating Substrate Topography Directed Osteogenic Differentiation Through High-Throughput siRNA Screening. Sci Rep 2019; 9:1001. [PMID: 30700820 PMCID: PMC6353928 DOI: 10.1038/s41598-018-37554-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/04/2018] [Indexed: 12/14/2022] Open
Abstract
Fibrous scaffolds are used for bone tissue engineering purposes with great success across a variety of polymers with different physical and chemical properties. It is now evident that the correct degree of curvature promotes increased cytoskeletal tension on osteoprogenitors leading to osteogenic differentiation. However, the mechanotransductive pathways involved in this phenomenon are not fully understood. To achieve a reproducible and specific cellular response, an increased mechanistic understanding of the molecular mechanisms driving the fibrous scaffold mediated bone regeneration must be understood. High throughput siRNA mediated screening technology has been utilized for dissecting molecular targets that are important in certain cellular phenotypes. In this study, we used siRNA mediated gene silencing to understand the osteogenic differentiation observed on fibrous scaffolds. A high-throughput siRNA screen was conducted using a library collection of 863 genes including important human kinase and phosphatase targets on pre-osteoblast SaOS-2 cells. The cells were grown on electrospun poly(methyl methacrylate) (PMMA) scaffolds with a diameter of 0.938 ± 0.304 µm and a flat surface control. The osteogenic transcription factor RUNX2 was quantified with an in-cell western (ICW) assay for the primary screen and significant targets were selected via two sample t-test. After selecting the significant targets, a secondary screen was performed to identify osteoinductive markers that also effect cell shape on fibrous topography. Finally, we report the most physiologically relevant molecular signaling mechanisms that are involved in growth factor free, fibrous topography mediated osteoinduction. We identified GTPases, membrane channel proteins, and microtubule associated targets that promote an osteoinductive cell shape on fibrous scaffolds.
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22
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Flusser H, Halperin D, Kadir R, Shorer Z, Shelef I, Birk OS. Novel SBF1 splice-site null mutation broadens the clinical spectrum of Charcot-Marie-Tooth type 4B3 disease. Clin Genet 2018; 94:473-479. [PMID: 30039846 DOI: 10.1111/cge.13419] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 07/13/2018] [Indexed: 11/29/2022]
Abstract
Four siblings of consanguineous Bedouin kindred presented at infancy with an autosomal recessive syndrome of congenital microcephaly, facial dysmorphism, strabismus, developmental delay and ataxia with positive pyramidal signs. Toward the end of their first decade, they developed areflexia, multiple cranial neuropathies and severe polyneuropathy with progressive muscle weakness, affecting proximal and distal extremities. Physical assessment exhibited kyphoscoliosis, bilateral syndactyly and distal muscle wasting with drop-foot and pes cavus. Magnetic resonance imaging (MRI) showed profound cerebellar atrophy with highly unique findings at the pontine and mesencephalic levels, previously described as "fork and bracket" signs. Genome-wide linkage analysis identified a single ~1.5 Mbp disease-associated locus on chromosome 22q13.33. Whole exome sequencing identified a single novel homozygous deleterious splice-site mutation within this locus in SET binding factor 1 (SBF1). SBF1 missense mutations were shown to underlie Charcot-Marie-Tooth (CMT) type 4B3 disease, a rare autosomal recessive subtype of CMT4. The novel SBF1 null mutation highlights distinct severe phenotypic manifestations, broadening the clinical spectrum of SBF1-related neuropathies: cerebellar and pyramidal signs evident in the first months of life with peripheral polyneuropathy emerging only toward the end of the first decade, together with unique MRI findings.
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Affiliation(s)
- H Flusser
- Zussman Child Development Center, Division of Pediatrics, Soroka Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - D Halperin
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - R Kadir
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Z Shorer
- Pediatric Neurology Unit, Division of Pediatrics, Soroka Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - I Shelef
- Department of Imaging, Soroka Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - O S Birk
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Genetics Institute, Soroka University Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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23
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Narayanan P, Hütte M, Kudryasheva G, Taberner FJ, Lechner SG, Rehfeldt F, Gomez-Varela D, Schmidt M. Myotubularin related protein-2 and its phospholipid substrate PIP 2 control Piezo2-mediated mechanotransduction in peripheral sensory neurons. eLife 2018. [PMID: 29521261 PMCID: PMC5898911 DOI: 10.7554/elife.32346] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Piezo2 ion channels are critical determinants of the sense of light touch in vertebrates. Yet, their regulation is only incompletely understood. We recently identified myotubularin related protein-2 (Mtmr2), a phosphoinositide (PI) phosphatase, in the native Piezo2 interactome of murine dorsal root ganglia (DRG). Here, we demonstrate that Mtmr2 attenuates Piezo2-mediated rapidly adapting mechanically activated (RA-MA) currents. Interestingly, heterologous Piezo1 and other known MA current subtypes in DRG appeared largely unaffected by Mtmr2. Experiments with catalytically inactive Mtmr2, pharmacological blockers of PI(3,5)P2 synthesis, and osmotic stress suggest that Mtmr2-dependent Piezo2 inhibition involves depletion of PI(3,5)P2. Further, we identified a PI(3,5)P2 binding region in Piezo2, but not Piezo1, that confers sensitivity to Mtmr2 as indicated by functional analysis of a domain-swapped Piezo2 mutant. Altogether, our results propose local PI(3,5)P2 modulation via Mtmr2 in the vicinity of Piezo2 as a novel mechanism to dynamically control Piezo2-dependent mechanotransduction in peripheral sensory neurons. We often take our sense of touch for granted. Yet, our every-day life greatly depends on the ability to perceive our environment to alert us of danger or to further social interactions, such as mother-child bonding. Our sense of touch relies on the conversion of mechanical stimuli to electrical signals (this is known as mechanotransduction), which then travel to brain to be processed. This task is fulfilled by specific ion channels called Piezo2, which are activated when cells are exposed to pressure and other mechanical forces. These channels can be found in sensory nerves and specialized structures in the skin, where they help to detect physical contact, roughness of surfaces and the position of our body parts. It is still not clear how Piezo2 channels are regulated but previous research by several laboratories suggests that they work in conjunction with other proteins. One of these proteins is the myotubularin related protein-2, or Mtmr2 for short. Now, Narayanan et al. – including some of the researchers involved in the previous research – set out to advance our understanding of the molecular basis of touch and looked more closely at Mtmr2. To test if Mtmr2 played a role in mechanotransduction, Narayanan et al. both increased and reduced the levels of this protein in sensory neurons of mice grown in the laboratory. When Mtmr2 levels were low, the activity of Piezo2 channels increased. However, when the protein levels were high, Piezo2 channels were inhibited. These results suggest that Mtmr2 can control the activity of Piezo2. Further experiments, in which Mtmr2 was genetically modified or sensory neurons were treated with chemicals, revealed that Mtmr2 reduces a specific fatty acid in the membrane of nerve cells, which in turn attenuates the activity of Piezo2. This study identified Mtmr2 and distinct fatty acids in the cell membrane as new components of the complex setup required for the sense of touch. A next step will be to test if these molecules also influence the activity of Piezo2 when the skin has become injured or upon inflammation.
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Affiliation(s)
- Pratibha Narayanan
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Meike Hütte
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Galina Kudryasheva
- Third Institute of Physics - Biophysics, University of Goettingen, Goettingen, Germany
| | | | | | - Florian Rehfeldt
- Third Institute of Physics - Biophysics, University of Goettingen, Goettingen, Germany
| | - David Gomez-Varela
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Manuela Schmidt
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
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24
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Raess MA, Cowling BS, Bertazzi DL, Kretz C, Rinaldi B, Xuereb JM, Kessler P, Romero NB, Payrastre B, Friant S, Laporte J. Expression of the neuropathy-associated MTMR2 gene rescues MTM1-associated myopathy. Hum Mol Genet 2018; 26:3736-3748. [PMID: 28934386 DOI: 10.1093/hmg/ddx258] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 06/28/2017] [Indexed: 01/15/2023] Open
Abstract
Myotubularins (MTMs) are active or dead phosphoinositides phosphatases defining a large protein family conserved through evolution and implicated in different neuromuscular diseases. Loss-of-function mutations in MTM1 cause the severe congenital myopathy called myotubular myopathy (or X-linked centronuclear myopathy) while mutations in the MTM1-related protein MTMR2 cause a recessive Charcot-Marie-Tooth peripheral neuropathy. Here we aimed to determine the functional specificity and redundancy of MTM1 and MTMR2, and to assess their abilities to compensate for a potential therapeutic strategy. Using molecular investigations and heterologous expression of human MTMs in yeast cells and in Mtm1 knockout mice, we characterized several naturally occurring MTMR2 isoforms with different activities. We identified the N-terminal domain as responsible for functional differences between MTM1 and MTMR2. An N-terminal extension observed in MTMR2 is absent in MTM1, and only the short MTMR2 isoform lacking this N-terminal extension behaved similarly to MTM1 in yeast and mice. Moreover, adeno-associated virus-mediated exogenous expression of several MTMR2 isoforms ameliorates the myopathic phenotype owing to MTM1 loss, with increased muscle force, reduced myofiber atrophy, and reduction of the intracellular disorganization hallmarks associated with myotubular myopathy. Noteworthy, the short MTMR2 isoform provided a better rescue when compared with the long MTMR2 isoform. In conclusion, these results point to the molecular basis for MTMs functional specificity. They also provide the proof-of-concept that expression of the neuropathy-associated MTMR2 gene improves the MTM1-associated myopathy, thus identifying MTMR2 as a novel therapeutic target for myotubular myopathy.
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Affiliation(s)
- Matthieu A Raess
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France.,INSERM U964, 67404 Illkirch, France.,CNRS, UMR7104, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France.,Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR7156, 67000 Strasbourg, France
| | - Belinda S Cowling
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France.,INSERM U964, 67404 Illkirch, France.,CNRS, UMR7104, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Dimitri L Bertazzi
- Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR7156, 67000 Strasbourg, France
| | - Christine Kretz
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France.,INSERM U964, 67404 Illkirch, France.,CNRS, UMR7104, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Bruno Rinaldi
- Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR7156, 67000 Strasbourg, France
| | - Jean-Marie Xuereb
- INSERM U1048 and Université Toulouse 3, Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), 31432 Toulouse, France
| | - Pascal Kessler
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France.,INSERM U964, 67404 Illkirch, France.,CNRS, UMR7104, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Norma B Romero
- INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Pitié-Salpêtrière Hospital, Sorbonne Universities, Pierre and Marie Curie University, 75013 Paris, France.,Unit of Neuromuscular Morphology, Institute of Myology.,Reference Center for Neuromuscular Pathology Paris-East, Institute of Myology, Public Hospital Network of Paris, Pitié-Salpêtrière Hospital, 75013 Paris, France
| | - Bernard Payrastre
- INSERM U1048 and Université Toulouse 3, Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), 31432 Toulouse, France.,CHU de Toulouse, Laboratoire d'Hématologie, 31059 Toulouse, France
| | - Sylvie Friant
- Department of Molecular and Cellular Genetics, Université de Strasbourg, CNRS, GMGM UMR7156, 67000 Strasbourg, France
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France.,INSERM U964, 67404 Illkirch, France.,CNRS, UMR7104, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
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25
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Manole A, Horga A, Gamez J, Raguer N, Salvado M, San Millán B, Navarro C, Pittmann A, Reilly MM, Houlden H. SBF1 mutations associated with autosomal recessive axonal neuropathy with cranial nerve involvement. Neurogenetics 2016; 18:63-67. [PMID: 28005197 DOI: 10.1007/s10048-016-0505-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 12/13/2016] [Indexed: 12/28/2022]
Abstract
Biallelic mutations in the SBF1 gene have been identified in one family with demyelinating Charcot-Marie-Tooth disease (CMT4B3) and two families with axonal neuropathy and additional neurological and skeletal features. Here we describe novel sequence variants in SBF1 (c.1168C>G and c.2209_2210del) as the potential causative mutations in two siblings with severe axonal neuropathy, hearing loss, facial weakness and bulbar features. Pathogenicity of these variants is supported by co-segregation and in silico analyses and evolutionary conservation. Our findings suggest that SBF1 mutations may cause a syndromic form of autosomal recessive axonal neuropathy (AR-CMT2) in addition to CMT4B3.
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Affiliation(s)
- Andreea Manole
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, Queen Square, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Alejandro Horga
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, Queen Square, London, UK
| | - Josep Gamez
- Neuromuscular Disorders Unit, Department of Neurology, Hospital Universitari Vall d'Hebron and Universitat Autònoma de Barcelona, VHIR, Passeig Vall d'Hebron, 119-135, 08035, Barcelona, Spain.
| | - Nuria Raguer
- Department of Neurophysiology, Hospital Universitari Vall d'Hebron and Universitat Autònoma de Barcelona, VHIR, Barcelona, Spain
| | - Maria Salvado
- Neuromuscular Disorders Unit, Department of Neurology, Hospital Universitari Vall d'Hebron and Universitat Autònoma de Barcelona, VHIR, Passeig Vall d'Hebron, 119-135, 08035, Barcelona, Spain
| | - Beatriz San Millán
- Department of Neuropathology, Complejo Hospitalario Universitario de Vigo, Vigo, Spain
| | - Carmen Navarro
- Department of Neuropathology, Complejo Hospitalario Universitario de Vigo, Vigo, Spain
| | - Alan Pittmann
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, Queen Square, London, UK
| | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, Queen Square, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
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26
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WANTED - Dead or alive: Myotubularins, a large disease-associated protein family. Adv Biol Regul 2016; 63:49-58. [PMID: 27666502 DOI: 10.1016/j.jbior.2016.09.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 09/13/2016] [Accepted: 09/13/2016] [Indexed: 11/21/2022]
Abstract
Myotubularins define a large family of proteins conserved through evolution. Several members are mutated in different neuromuscular diseases including centronuclear myopathies and Charcot-Marie-Tooth (CMT) neuropathies, or are linked to a predisposition to obesity and cancer. While some members have phosphatase activity against the 3-phosphate of phosphoinositides, regulating the phosphorylation status of PtdIns3P and PtdIns(3,5)P2 implicated in membrane trafficking and autophagy, and producing PtdIns5P, others lack key residues in the catalytic site and are classified as dead-phosphatases. However, these dead phosphatases regulate phosphoinositide-dependent cellular pathways by binding to catalytically active myotubularins. Here we review previous studies on the molecular regulation and physiological roles of myotubularins. We also used the recent myotubularins three-dimensional structures to underline key residues that are mutated in neuromuscular diseases and required for enzymatic activity. In addition, through database mining and analysis, expression profile and specific isoforms of the different myotubularins are described in depth, as well as a revisited protein interaction network. Comparison of the interactome and expression data for each myotubularin highlights specific protein complexes and tissues where myotubularins should have a key regulatory role.
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27
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Scott P, Bruwer Z, Al-Kharusi K, Meftah D, Al-Murshedi F. Occurrence of Optic Neuritis and Cervical Cord Schwannoma with Charcot-Marie-Tooth Type 4B1 Disease. Oman Med J 2016; 31:227-30. [PMID: 27162595 DOI: 10.5001/omj.2016.43] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Charcot-Marie-Tooth neuropathy type 4B1 (CMT4B1) disease is a rare subtype of CMT4 with reported association of facial weakness, vocal cord paresis, chest deformities, and claw hands. We report the unusual occurrence of optic neuritis and cervical cord schwannoma in a male individual with confirmed CMT4B1 disease. Sequencing of the MTMR2 gene revealed a novel nonsense homozygous mutation c.1768C>T (p.Gln590*). The mutation was identified in affected relatives of the proband and a second, apparently unrelated, family. The rare association of optic neuritis or schwannoma with genetically confirmed CMT1A has been individually observed, but never with recessive CMT. To the best of our knowledge, the occurrence of optic neuritis and cervical cord schwannoma in the same patient has never been reported with any form of CMT including CMT4B1. In similar cases, we recommend immediate medical attention to rule out the possibility of schwannomas in patients with all demyelinating CMT subtypes in case of the development of focal neurological signs or acute worsening of clinical status.
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Affiliation(s)
- Patrick Scott
- Department of Genetics, Sultan Qaboos University Hospital, Muscat, Oman
| | - Zandre Bruwer
- Department of Genetics, Sultan Qaboos University Hospital, Muscat, Oman
| | - Khalsa Al-Kharusi
- Department of Genetics, Sultan Qaboos University Hospital, Muscat, Oman
| | - Douja Meftah
- Department of Genetics, Sultan Qaboos University Hospital, Muscat, Oman
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Bong SM, Son KB, Yang SW, Park JW, Cho JW, Kim KT, Kim H, Kim SJ, Kim YJ, Lee BI. Crystal Structure of Human Myotubularin-Related Protein 1 Provides Insight into the Structural Basis of Substrate Specificity. PLoS One 2016; 11:e0152611. [PMID: 27018598 PMCID: PMC4809516 DOI: 10.1371/journal.pone.0152611] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 03/16/2016] [Indexed: 01/07/2023] Open
Abstract
Myotubularin-related protein 1 (MTMR1) is a phosphatase that belongs to the tyrosine/dual-specificity phosphatase superfamily. MTMR1 has been shown to use phosphatidylinositol 3-monophosphate (PI(3)P) and/or phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) as substrates. Here, we determined the crystal structure of human MTMR1. The refined model consists of the Pleckstrin homology (PH)-GRAM and phosphatase (PTP) domains. The overall structure was highly similar to the previously reported MTMR2 structure. Interestingly, two phosphate molecules were coordinated by strictly conserved residues located in the C(X)5R motif of the active site. Additionally, our biochemical studies confirmed the substrate specificity of MTMR1 for PI(3)P and PI(3,5)P2 over other phosphatidylinositol phosphates. Our structural and enzymatic analyses provide insight into the catalytic mechanism and biochemical properties of MTMR1.
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Affiliation(s)
- Seoung Min Bong
- Research institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
| | - Kka-bi Son
- Department of Biomedical Chemistry, Konkuk University, Chungju 27478, Republic of Korea
| | - Seung-Won Yang
- Research institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
| | - Jae-Won Park
- Research institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
| | - Jea-Won Cho
- Research institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
| | - Kyung-Tae Kim
- Research institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
| | - Hackyoung Kim
- Department of Biomedical Chemistry, Konkuk University, Chungju 27478, Republic of Korea
| | - Seung Jun Kim
- Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Young Jun Kim
- Department of Biomedical Chemistry, Konkuk University, Chungju 27478, Republic of Korea
- * E-mail: (YJK); (BIL)
| | - Byung Il Lee
- Research institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
- * E-mail: (YJK); (BIL)
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Dysregulation of ErbB Receptor Trafficking and Signaling in Demyelinating Charcot-Marie-Tooth Disease. Mol Neurobiol 2016; 54:87-100. [PMID: 26732592 DOI: 10.1007/s12035-015-9668-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/17/2015] [Indexed: 12/12/2022]
Abstract
Charcot-Marie-Tooth (CMT) disease is the most common inherited peripheral neuropathy with the majority of cases involving demyelination of peripheral nerves. The pathogenic mechanisms of demyelinating CMT remain unclear, and no effective therapy currently exists for this disease. The discovery that mutations in different genes can cause a similar phenotype of demyelinating peripheral neuropathy raises the possibility that there may be convergent mechanisms leading to demyelinating CMT pathogenesis. Increasing evidence indicates that ErbB receptor-mediated signaling plays a major role in the control of Schwann cell-axon communication and myelination in the peripheral nervous system. Recent studies reveal that several demyelinating CMT-linked proteins are novel regulators of endocytic trafficking and/or phosphoinositide metabolism that may affect ErbB receptor signaling. Emerging data have begun to suggest that dysregulation of ErbB receptor trafficking and signaling in Schwann cells may represent a common pathogenic mechanism in multiple subtypes of demyelinating CMT. In this review, we focus on the roles of ErbB receptor trafficking and signaling in regulation of peripheral nerve myelination and discuss the emerging evidence supporting the potential involvement of altered ErbB receptor trafficking and signaling in demyelinating CMT pathogenesis and the possibility of modulating these trafficking and signaling processes for treating demyelinating peripheral neuropathy.
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Yoo KY, Son JY, Lee JU, Shin W, Im DW, Kim SJ, Ryu SE, Heo YS. Structure of the catalytic phosphatase domain of MTMR8: implications for dimerization, membrane association and reversible oxidation. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1528-39. [PMID: 26143924 DOI: 10.1107/s139900471500927x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/15/2015] [Indexed: 11/11/2022]
Abstract
Myotubularin-related proteins are a large family of phosphoinositide phosphatases; their activity, stability and subcellular localization are regulated by dimeric interactions with other members of the family. Here, the crystal structure of the phosphatase domain of MTMR8 is reported. Conformational deviation of the two loops that mediate interaction with the PH-GRAM domain suggests that the PH-GRAM domain interacts differently with the phosphatase domain of each MTMR member. The protein exists as a dimer with twofold symmetry, providing insight into a novel mode of dimerization mediated by the phosphatase domain. Structural comparison and mutation studies suggest that Lys255 of MTMR8 interacts with the substrate diacylglycerol moiety, similar to Lys333 of MTMR2, although the positions of these residues are different. The catalytic activity of the MTMR8 phosphatase domain is inhibited by oxidation and is reversibly reactivated by reduction, suggesting the presence of an oxidation-protective intermediate other than a disulfide bond owing to the absence of a cysteine within a disulfide-bond distance from Cys338.
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Affiliation(s)
- Ki Young Yoo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Ji Young Son
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Jee Un Lee
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Woori Shin
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Dong Won Im
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Seung Jun Kim
- Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Seong Eon Ryu
- Department of Bio Engineering, Hanyang University, Seongdong-gu, Seoul 133-791, Republic of Korea
| | - Yong Seok Heo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
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St-Denis N, Gupta GD, Lin ZY, Gonzalez-Badillo B, Pelletier L, Gingras AC. Myotubularin-related proteins 3 and 4 interact with polo-like kinase 1 and centrosomal protein of 55 kDa to ensure proper abscission. Mol Cell Proteomics 2015; 14:946-60. [PMID: 25659891 PMCID: PMC4390272 DOI: 10.1074/mcp.m114.046086] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/22/2015] [Indexed: 11/06/2022] Open
Abstract
The myotubularins are a family of phosphatases that dephosphorylate the phosphatidylinositols phosphatidylinositol-3-phosphate and phosphatidylinositol-3,5-phosphate. Several family members are mutated in disease, yet the biological functions of the majority of myotubularins remain unknown. To gain insight into the roles of the individual enzymes, we have used affinity purification coupled to mass spectrometry to identify protein-protein interactions for the myotubularins. The myotubularin interactome comprises 66 high confidence (false discovery rate ≤1%) interactions, including 18 pairwise interactions between individual myotubularins. The results reveal a number of potential signaling contexts for this family of enzymes, including an intriguing, novel role for myotubularin-related protein 3 and myotubularin-related protein 4 in the regulation of abscission, the final step of mitosis in which the membrane bridge remaining between two daughter cells is cleaved. Both depletion and overexpression of either myotubularin-related protein 3 or myotubularin-related protein 4 result in abnormal midbody morphology and cytokinesis failure. Interestingly, myotubularin-related protein 3 and myotubularin-related protein 4 do not exert their effects through lipid regulation at the midbody, but regulate abscission during early mitosis, by interacting with the mitotic kinase polo-like kinase 1, and with centrosomal protein of 55 kDa (CEP55), an important regulator of abscission. Structure-function analysis reveals that, consistent with known intramyotubularin interactions, myotubularin-related protein 3 and myotubularin-related protein 4 interact through their respective coiled coil domains. The interaction between myotubularin-related protein 3 and polo-like kinase 1 relies on the divergent, nonlipid binding Fab1, YOTB, Vac1, and EEA1 domain of myotubularin-related protein 3, and myotubularin-related protein 4 interacts with CEP55 through a short GPPXXXY motif, analogous to endosomal sorting complex required for transport-I components. Disruption of any of these interactions results in abscission failure, by disrupting the proper recruitment of CEP55, and subsequently, of endosomal sorting complex required for transport-I, to the midbody. Our data suggest that myotubularin-related protein 3 and myotubularin-related protein 4 may act as a bridge between CEP55 and polo-like kinase 1, ensuring proper CEP55 phosphorylation and regulating CEP55 recruitment to the midbody. This work provides a novel role for myotubularin-related protein 3/4 heterodimers, and highlights the temporal and spatial complexity of the regulation of cytokinesis.
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Affiliation(s)
- Nicole St-Denis
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Gagan D Gupta
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Zhen Yuan Lin
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Beatriz Gonzalez-Badillo
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Laurence Pelletier
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; §Department of Molecular Genetics, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Anne-Claude Gingras
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; §Department of Molecular Genetics, University of Toronto, Toronto ON M5S 1A8, Canada
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Hatzihristidis T, Desai N, Hutchins AP, Meng TC, Tremblay ML, Miranda-Saavedra D. A Drosophila-centric view of protein tyrosine phosphatases. FEBS Lett 2015; 589:951-66. [PMID: 25771859 DOI: 10.1016/j.febslet.2015.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/02/2015] [Accepted: 03/02/2015] [Indexed: 12/30/2022]
Abstract
Most of our knowledge on protein tyrosine phosphatases (PTPs) is derived from human pathologies and mouse knockout models. These models largely correlate well with human disease phenotypes, but can be ambiguous due to compensatory mechanisms introduced by paralogous genes. Here we present the analysis of the PTP complement of the fruit fly and the complementary view that PTP studies in Drosophila will accelerate our understanding of PTPs in physiological and pathological conditions. With only 44 PTP genes, Drosophila represents a streamlined version of the human complement. Our integrated analysis places the Drosophila PTPs into evolutionary and functional contexts, thereby providing a platform for the exploitation of the fly for PTP research and the transfer of knowledge onto other model systems.
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Affiliation(s)
- Teri Hatzihristidis
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue, Montreal, Québec H3A 1A3, Canada; Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Nikita Desai
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue, Montreal, Québec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Andrew P Hutchins
- Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong 510530, China
| | - Tzu-Ching Meng
- Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan; Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Michel L Tremblay
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue, Montreal, Québec H3A 1A3, Canada; Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada; Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
| | - Diego Miranda-Saavedra
- World Premier International (WPI) Immunology Frontier Research Center (IFReC), Osaka University, 3-1 Yamadaoka, Suita 565-0871, Osaka, Japan; Centro de Biología Molecular Severo Ochoa, CSIC/Universidad Autónoma de Madrid, 28049 Madrid, Spain; IE Business School, IE University, María de Molina 31 bis, 28006 Madrid, Spain.
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Bong SM, Yang SW, Choi JW, Kim SJ, Lee BI. Crystallization and preliminary X-ray crystallographic analysis of human myotubularin-related protein 1. Acta Crystallogr F Struct Biol Commun 2015; 71:261-5. [PMID: 25760698 PMCID: PMC4356299 DOI: 10.1107/s2053230x15000606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 01/12/2015] [Indexed: 11/10/2022] Open
Abstract
Myotubularin-related protein 1 is a phosphatase that dephosphorylates phospholipids such as phosphatidylinositol 3-phosphate or phosphatidylinositol 3,5-bisphosphate. In this study, human MTMR1 was overexpressed in Escherichia coli, purified and crystallized at 277 K using polyethylene glycol 20,000 as a precipitant. Diffraction data were collected to 2.0 Å resolution using synchrotron radiation. The crystals belonged to space group P1, with unit-cell parameters a = 67.219, b = 96.587, c = 97.581 Å, α = 87.597, β = 86.072, γ = 77.327°. Assuming the presence of four molecules in the asymmetric unit, the calculated Matthews coefficient value was 2.61 Å(3) Da(-1) and the corresponding solvent content was 52.9%.
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Affiliation(s)
- Seoung Min Bong
- Biomolecular Function Research Branch, Division of Convergence Technology, Research Institute, National Cancer Center, Goyang, Gyeonggi 411-769, Republic of Korea
| | - Seung Won Yang
- Biomolecular Function Research Branch, Division of Convergence Technology, Research Institute, National Cancer Center, Goyang, Gyeonggi 411-769, Republic of Korea
| | - Ji-Woong Choi
- Biomolecular Function Research Branch, Division of Convergence Technology, Research Institute, National Cancer Center, Goyang, Gyeonggi 411-769, Republic of Korea
| | - Seung Jun Kim
- Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea
| | - Byung Il Lee
- Biomolecular Function Research Branch, Division of Convergence Technology, Research Institute, National Cancer Center, Goyang, Gyeonggi 411-769, Republic of Korea
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34
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Mendelian disorders of PI metabolizing enzymes. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:867-81. [PMID: 25510381 DOI: 10.1016/j.bbalip.2014.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/18/2014] [Accepted: 12/01/2014] [Indexed: 12/18/2022]
Abstract
More than twenty different genetic diseases have been described that are caused by mutations in phosphoinositide metabolizing enzymes, mostly in phosphoinositide phosphatases. Although generally ubiquitously expressed, mutations in these enzymes, which are mainly loss-of-function, result in tissue-restricted clinical manifestations through mechanisms that are not completely understood. Here we analyze selected disorders of phosphoinositide metabolism grouped according to the principle tissue affected: the nervous system, muscle, kidney, the osteoskeletal system, the eye, and the immune system. We will highlight what has been learnt so far from the study of these disorders about not only the cellular and molecular pathways that are involved or are governed by phosphoinositides, but also the many gaps that remain to be filled to gain a full understanding of the pathophysiological mechanisms underlying the clinical manifestations of this steadily growing class of diseases, most of which still remain orphan in terms of treatment. This article is part of a Special Issue entitled Phosphoinositides.
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Hsu F, Mao Y. The structure of phosphoinositide phosphatases: Insights into substrate specificity and catalysis. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:698-710. [PMID: 25264170 DOI: 10.1016/j.bbalip.2014.09.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/10/2014] [Accepted: 09/17/2014] [Indexed: 12/17/2022]
Abstract
Phosphoinositides (PIs) are a group of key signaling and structural lipid molecules involved in a myriad of cellular processes. PI phosphatases, together with PI kinases, are responsible for the conversion of PIs between distinctive phosphorylation states. PI phosphatases are a large collection of enzymes that are evolved from at least two disparate ancestors. One group is distantly related to endonucleases, which apply divalent metal ions for phosphoryl transfer. The other group is related to protein tyrosine phosphatases, which contain a highly conserved active site motif Cys-X5-Arg (CX5R). In this review, we focus on structural insights to illustrate current understandings of the molecular mechanisms of each PI phosphatase family, with emphasis on their structural basis for substrate specificity determinants and catalytic mechanisms. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- FoSheng Hsu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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Son JY, Lee JU, Yoo KY, Shin W, Im DW, Kim SJ, Ryu SE, Heo YS. Expression, purification, crystallization and preliminary crystallographic analysis of human myotubularin-related protein 3. Acta Crystallogr F Struct Biol Commun 2014; 70:1240-3. [PMID: 25195900 PMCID: PMC4157427 DOI: 10.1107/s2053230x14015714] [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: 06/04/2014] [Accepted: 07/05/2014] [Indexed: 11/10/2022] Open
Abstract
Myotubularin-related proteins are a large family of phosphatases that have the catalytic activity of dephosphorylating the phospholipid molecules phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate. Each of the 14 family members contains a phosphatase catalytic domain, which is inactive in six family members owing to amino-acid changes in a key motif for the activity. All of the members also bear PH-GRAM domains, which have low homologies between them and have roles that are not yet clear. Here, the cloning, expression, purification and crystallization of human myotubularin-related protein 3 encompassing the PH-GRAM and the phosphatase catalytic domain are reported. Preliminary X-ray crystallographic analysis shows that the crystals diffracted to 3.30 Å resolution at a synchrotron X-ray source. The crystals belonged to space group C2, with unit-cell parameters a = 323.3, b = 263.3, c = 149.4 Å, β = 109.7°.
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Affiliation(s)
- Ji Young Son
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Jee Un Lee
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Ki-Young Yoo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Woori Shin
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Dong-Won Im
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Seung Jun Kim
- Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Seong Eon Ryu
- Department of Bio Engineering, Hanyang University, Seongdong-gu, Seoul 133-791, Republic of Korea
| | - Yong-Seok Heo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
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Lee JU, Son JY, Yoo KY, Shin W, Im DW, Kim SJ, Ryu SE, Heo YS. Crystallization and preliminary X-ray crystallographic analysis of the PH-GRAM domain of human MTMR4. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:1280-3. [PMID: 25195910 DOI: 10.1107/s2053230x14017658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/31/2014] [Indexed: 11/10/2022]
Abstract
Phosphoinositide lipid molecules play critical roles in intracellular signalling pathways and are regulated by phospholipases, lipid kinases and phosphatases. In particular, phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate are related to endosomal trafficking events through the recruitment of effector proteins and are involved in the degradation step of autophagy. Myotubularin-related proteins (MTMRs) are a large family of phosphatases that catalyze the dephosphorylation of phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate at the D3 position, thereby regulating cellular phosphoinositide levels. In this study, the PH-GRAM domain of human MTMR4 was cloned, overexpressed in Escherichia coli, purified and crystallized by the vapour-diffusion method. The crystals diffracted to 3.20 Å resolution at a synchrotron beamline and belonged to either space group P61 or P65, with unit-cell parameters a = b = 109.10, c = 238.97 Å.
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Affiliation(s)
- Jee Un Lee
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Ji Young Son
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Ki-Young Yoo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Woori Shin
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Dong-Won Im
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Seung Jun Kim
- Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Seong Eon Ryu
- Department of Bio Engineering, Hanyang University, Seongdong-gu, Seoul 133-791, Republic of Korea
| | - Yong-Seok Heo
- Department of Chemistry, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
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Niemi NM, Sacoman JL, Westrate LM, Gaither LA, Lanning NJ, Martin KR, MacKeigan JP. The pseudophosphatase MK-STYX physically and genetically interacts with the mitochondrial phosphatase PTPMT1. PLoS One 2014; 9:e93896. [PMID: 24709986 PMCID: PMC3977970 DOI: 10.1371/journal.pone.0093896] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 03/11/2014] [Indexed: 11/19/2022] Open
Abstract
We previously performed an RNA interference (RNAi) screen and found that the knockdown of the catalytically inactive phosphatase, MK-STYX [MAPK (mitogen-activated protein kinase) phospho-serine/threonine/tyrosine-binding protein], resulted in potent chemoresistance. Our follow-up studies demonstrated that knockdown of MK-STYX prevents cells from undergoing apoptosis through a block in cytochrome c release, but that MK-STYX does not localize proximal to the molecular machinery currently known to control this process. In an effort to define its molecular mechanism, we utilized an unbiased proteomics approach to identify proteins that interact with MK-STYX. We identified the mitochondrial phosphatase, PTPMT1 (PTP localized to mitochondrion 1), as the most significant and unique interaction partner of MK-STYX. We previously reported that knockdown of PTPMT1, an important component of the cardiolipin biosynthetic pathway, is sufficient to induce apoptosis and increase chemosensitivity. Accordingly, we hypothesized that MK-STYX and PTPMT1 interact and serve opposing functions in mitochondrial-dependent cell death. We confirmed that MK-STYX and PTPMT1 interact in cells and, importantly, found that MK-STYX suppresses PTPMT1 catalytic activity. Furthermore, we found that knockdown of PTPMT1 resensitizes MK-STYX knockdown cells to chemotherapeutics and restores the ability to release cytochrome c. Taken together, our data support a model in which MK-STYX controls apoptosis by negatively regulating PTPMT1. Given the important role of PTPMT1 in the production of cardiolipin and other phospholipids, this raises the possibility that dysregulated mitochondrial lipid metabolism may facilitate chemoresistance.
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Affiliation(s)
- Natalie M. Niemi
- Laboratory of Systems Biology, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Juliana L. Sacoman
- Laboratory of Systems Biology, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Laura M. Westrate
- Laboratory of Systems Biology, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - L. Alex Gaither
- Developmental and Molecular Pathways Department, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Nathan J. Lanning
- Laboratory of Systems Biology, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Katie R. Martin
- Laboratory of Systems Biology, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Jeffrey P. MacKeigan
- Laboratory of Systems Biology, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
- * E-mail:
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Zhu MH, Ji SL, Zhang CY, Cui L, Xiong L, Zheng HL. DNA microarray reveals ZNF195 and SBF1 are potential biomarkers for gemcitabine sensitivity in head and neck squamous cell carcinoma cell lines. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:1514-1523. [PMID: 24817947 PMCID: PMC4014231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/08/2014] [Indexed: 06/03/2023]
Abstract
Gemcitabine is a potential chemotherapy drug for treatment of head and neck squamous cell carcinoma (HNSCC), however, the poor or partial response of HNSCC patients to gemcitabine demonstrated the urgent need for gemcitabine biomarkers to improve the therapy. In present work, 10 HNSCC cell lines were employed to figure out the biomarkers for gemcitabine sensitivity. The sensitivities of these 10 cell lines to gemcitabine and the basal expression of these cell lines was investigated, the correlation between gemcitabine response (IC50 dose) and gene expression was investigated by Pearson correlation and FDR estimation. The top seven positive genes responsible for gemcitabine sensitivity were validated by qPCR in these 10 HNSCC cell lines, while only two genes (SBF1 and ZNF195) were expression-correlated to gemcitabine response. Furthermore, ZNF195 expression was closely associated with gemcitabine sensitivity in the subsequent independent validation in cell lines from various types of cancer. Our work might provide potential biomarkers for gemcitabine sensitivity in HNSCC and various type of cancer.
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Affiliation(s)
- Min-Hui Zhu
- Department of Otorhinolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University Shanghai, China
| | - Shun-Long Ji
- Department of Otorhinolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University Shanghai, China
| | - Cai-Yun Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University Shanghai, China
| | - Long Cui
- Department of Otorhinolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University Shanghai, China
| | - Lei Xiong
- Department of Otorhinolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University Shanghai, China
| | - Hong-Liang Zheng
- Department of Otorhinolaryngology-Head and Neck Surgery, Changhai Hospital, Second Military Medical University Shanghai, China
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Kharitidi D, Manteghi S, Pause A. Pseudophosphatases: methods of analysis and physiological functions. Methods 2013; 65:207-18. [PMID: 24064037 DOI: 10.1016/j.ymeth.2013.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/20/2013] [Accepted: 09/11/2013] [Indexed: 01/27/2023] Open
Abstract
Protein tyrosine phosphatases (PTPs) are key enzymes in the regulation of cellular homeostasis and signaling pathways. Strikingly, not all PTPs bear enzymatic activity. A considerable fraction of PTPs are enzymatically inactive and are known as pseudophosphatases. Despite the lack of activity they execute pivotal roles in development, cell biology and human disease. The present review is focused on the methods used to identify pseudophosphatases, their targets, and physiological roles. We present a strategy for detailed enzymatic analysis of inactive PTPs, regulation of inactive PTP domains and identification of binding partners. Furthermore, we provide a detailed overview of human pseudophosphatases and discuss their regulation of cellular processes and functions in human pathologies.
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Affiliation(s)
- Dmitri Kharitidi
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, 3655, Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada.
| | - Sanaz Manteghi
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, 3655, Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada.
| | - Arnim Pause
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, 3655, Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada.
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Chu PL, Keum S, Marchuk DA. A novel genetic locus modulates infarct volume independently of the extent of collateral circulation. Physiol Genomics 2013; 45:751-63. [PMID: 23800850 DOI: 10.1152/physiolgenomics.00063.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In the mouse model of permanent, middle cerebral artery occlusion, infarct volume varies widely across inbred strains but generally is inversely correlated with collateral vessel number. However, we also observed certain mouse strains that share similar collateral vessel anatomy but exhibit significantly different infarct volume. To identify genetic factors determining infarct volume in a collateral vessel-independent manner, we performed quantitative trait locus analysis on a F2 cross between C57BL/6J and C3H/HeJ strains. We mapped four novel loci (Civq4 through Civq7) that modulate infarct volume. Civq4, on chromosome 8, is the strongest locus (logarithm of the odds 9.8) that contributes 21% of the phenotypic variance of infarct volume in the cross. The Civq4 and Civq6 loci represent transgressive B6 alleles that render animals susceptible to larger infarcts. Based on genomic sequence and microarray analyses, we propose candidate genes for the Civq4 locus. By selecting inbred strains with similar collateral vessel anatomy but that vary significantly in infarct volume, we have mapped four loci determining infarct volume in a mouse model of ischemic stroke. Two of the loci appear to modulate infarct volume through a collateral vessel-independent mechanism. Based on strain-specific sequence variants and differences in transcript levels, Msr1 and Mtmr7 appear to be strong candidate genes for Civq4. Identifying the underlying genetic factors of these loci will elucidate the genetic architecture response to cerebral ischemia, shed new light on disease mechanisms of ischemic stroke, and identify potential therapeutic targets for clinical applications.
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Affiliation(s)
- Pei-Lun Chu
- University Program in Genetics and Genomics and the Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
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43
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Zou J, Majerus PW, Wilson DB, Schrade A, Chang SC, Wilson MP. The role of myotubularin-related phosphatases in the control of autophagy and programmed cell death. Adv Biol Regul 2013; 52:282-9. [PMID: 22056831 DOI: 10.1016/j.advenzreg.2011.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 10/18/2011] [Indexed: 11/30/2022]
Affiliation(s)
- Jun Zou
- Division of Hematology, Washington University School of Medicine, 660 S. Euclid, St. Louis, MO 63110, USA
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44
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Gupta VA, Hnia K, Smith LL, Gundry SR, McIntire JE, Shimazu J, Bass JR, Talbot EA, Amoasii L, Goldman NE, Laporte J, Beggs AH. Loss of catalytically inactive lipid phosphatase myotubularin-related protein 12 impairs myotubularin stability and promotes centronuclear myopathy in zebrafish. PLoS Genet 2013; 9:e1003583. [PMID: 23818870 PMCID: PMC3688503 DOI: 10.1371/journal.pgen.1003583] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 05/07/2013] [Indexed: 01/08/2023] Open
Abstract
X-linked myotubular myopathy (XLMTM) is a congenital disorder caused by mutations of the myotubularin gene, MTM1. Myotubularin belongs to a large family of conserved lipid phosphatases that include both catalytically active and inactive myotubularin-related proteins (i.e., "MTMRs"). Biochemically, catalytically inactive MTMRs have been shown to form heteroligomers with active members within the myotubularin family through protein-protein interactions. However, the pathophysiological significance of catalytically inactive MTMRs remains unknown in muscle. By in vitro as well as in vivo studies, we have identified that catalytically inactive myotubularin-related protein 12 (MTMR12) binds to myotubularin in skeletal muscle. Knockdown of the mtmr12 gene in zebrafish resulted in skeletal muscle defects and impaired motor function. Analysis of mtmr12 morphant fish showed pathological changes with central nucleation, disorganized Triads, myofiber hypotrophy and whorled membrane structures similar to those seen in X-linked myotubular myopathy. Biochemical studies showed that deficiency of MTMR12 results in reduced levels of myotubularin protein in zebrafish and mammalian C2C12 cells. Loss of myotubularin also resulted in reduction of MTMR12 protein in C2C12 cells, mice and humans. Moreover, XLMTM mutations within the myotubularin interaction domain disrupted binding to MTMR12 in cell culture. Analysis of human XLMTM patient myotubes showed that mutations that disrupt the interaction between myotubularin and MTMR12 proteins result in reduction of both myotubularin and MTMR12. These studies strongly support the concept that interactions between myotubularin and MTMR12 are required for the stability of their functional protein complex in normal skeletal muscles. This work highlights an important physiological function of catalytically inactive phosphatases in the pathophysiology of myotubular myopathy and suggests a novel therapeutic approach through identification of drugs that could stabilize the myotubularin-MTMR12 complex and hence ameliorate this disorder.
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Affiliation(s)
- Vandana A. Gupta
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Karim Hnia
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Inserm U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Chaire de Génétique Humaine, Illkirch, France
| | - Laura L. Smith
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Stacey R. Gundry
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jessica E. McIntire
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Junko Shimazu
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jessica R. Bass
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ethan A. Talbot
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Leonela Amoasii
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Inserm U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Chaire de Génétique Humaine, Illkirch, France
| | - Nathaniel E. Goldman
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Inserm U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Chaire de Génétique Humaine, Illkirch, France
| | - Alan H. Beggs
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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45
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Lipid phosphatases identified by screening a mouse phosphatase shRNA library regulate T-cell differentiation and protein kinase B AKT signaling. Proc Natl Acad Sci U S A 2013; 110:E1849-56. [PMID: 23630283 DOI: 10.1073/pnas.1305070110] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Screening a complete mouse phosphatase lentiviral shRNA library using high-throughput sequencing revealed several phosphatases that regulate CD4 T-cell differentiation. We concentrated on two lipid phosphatases, the myotubularin-related protein (MTMR)9 and -7. Silencing MTMR9 by shRNA or siRNA resulted in enhanced T-helper (Th)1 differentiation and increased Th1 protein kinase B (PKB)/AKT phosphorylation while silencing MTMR7 caused increased Th2 and Th17 differentiation and increased AKT phosphorylation in these cells. Irradiated mice reconstituted with MTMR9 shRNA-transduced bone marrow cells had an elevated proportion of T-box transcription factor T-bet expressors among their CD4 T cells. After adoptive transfer of naïve cells from such reconstituted mice, immunization resulted in a greater proportion of T-box transcription factor T-bet-expressing cells. Thus, myotubularin-related proteins have a role in controlling in vitro and in vivo Th-cell differentiation, possibly through regulation of phosphatidylinositol [3,4,5]-trisphosphate activity.
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46
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Franklin NE, Bonham CA, Xhabija B, Vacratsis PO. Differential phosphorylation of the phosphoinositide 3-phosphatase MTMR2 regulates its association with early endosomal subtypes. J Cell Sci 2013; 126:1333-44. [PMID: 23378027 DOI: 10.1242/jcs.113928] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myotubularin-related 2 (MTMR2) is a 3-phosphoinositide lipid phosphatase with specificity towards the D-3 position of phosphoinositol 3-phosphate [PI(3)P] and phosphoinositol 3,5-bisphosphate lipids enriched on endosomal structures. Recently, we have shown that phosphorylation of MTMR2 on Ser58 is responsible for its cytoplasmic sequestration and that a phosphorylation-deficient variant (S58A) targets MTMR2 to Rab5-positive endosomes resulting in PI(3)P depletion and an increase in endosomal signaling, including a significant increase in ERK1/2 activation. Using in vitro kinase assays, cellular MAPK inhibitors, siRNA knockdown and a phosphospecific-Ser58 antibody, we now provide evidence that ERK1/2 is the kinase responsible for phosphorylating MTMR2 at position Ser58, which suggests that the endosomal targeting of MTMR2 is regulated through an ERK1/2 negative feedback mechanism. Surprisingly, treatment with multiple MAPK inhibitors resulted in a MTMR2 localization shift from Rab5-positive endosomes to the more proximal APPL1-positive endosomes. This MTMR2 localization shift was recapitulated when a double phosphorylation-deficient mutant (MTMR2 S58A/S631A) was characterized. Moreover, expression of this double phosphorylation-deficient MTMR2 variant led to a more sustained and pronounced increase in ERK1/2 activation compared with MTMR2 S58A. Further analysis of combinatorial phospho-mimetic mutants demonstrated that it is the phosphorylation status of Ser58 that regulates general endosomal binding and that the phosphorylation status of Ser631 mediates the endosomal shuttling between Rab5 and APPL1 subtypes. Taken together, these results reveal that MTMR2 compartmentalization and potential subsequent effects on endosome maturation and endosome signaling are dynamically regulated through MAPK-mediated differential phosphorylation events.
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Affiliation(s)
- Norah E Franklin
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B3P4, Canada
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47
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Mochizuki Y, Ohashi R, Kawamura T, Iwanari H, Kodama T, Naito M, Hamakubo T. Phosphatidylinositol 3-phosphatase myotubularin-related protein 6 (MTMR6) is regulated by small GTPase Rab1B in the early secretory and autophagic pathways. J Biol Chem 2012. [PMID: 23188820 DOI: 10.1074/jbc.m112.395087] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A large family of myotubularin phosphatases dephosphorylates phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate, which are known to play important roles in vesicular trafficking and autophagy. The family is composed of 16 members, and understanding their regulatory mechanisms is important to understand their functions and related genetic diseases. We prepared anti-myotubularin-related protein 6 (MTMR6) monoclonal antibody and used it to study the regulatory mechanism of MTMR6. Endogenous MTMR6 was present in the cytoplasm and was condensed in the perinuclear region in a microtubule-dependent manner. MTMR6 preferentially interacted with GDP-bound Rab1B via the GRAM domain and partly overlapped with Rab1B in the pericentrosomal and peri-Golgi regions in normal rat kidney cells. Overexpression of GDP-bound Rab1B and the reduction of Rab1B disrupted the localization of MTMR6, suggesting that Rab1B regulates the localization of MTMR6. The reduction of MTMR6 accelerated the transport of vesicular stomatitis virus glycoprotein in which Rab1B is involved. Furthermore, reduction of MTMR6 or Rab1B inhibited the formation of the tubular omegasome that is induced by overexpression of DFCP1 in autophagy. Our results indicate that the cellular localization of MTMR6 is regulated by Rab1B in the early secretory and autophagic pathways. We propose a new regulatory mechanism of myotubularin phosphatase by the small GTPase Rab1B.
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Affiliation(s)
- Yasuhiro Mochizuki
- Department of Molecular Biology and Medicine, The University of Tokyo, Tokyo 153-8904, Japan.
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48
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Myotubularin phosphoinositide phosphatases: cellular functions and disease pathophysiology. Trends Mol Med 2012; 18:317-27. [DOI: 10.1016/j.molmed.2012.04.004] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 11/23/2022]
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Myotubularin-related protein (MTMR) 9 determines the enzymatic activity, substrate specificity, and role in autophagy of MTMR8. Proc Natl Acad Sci U S A 2012; 109:9539-44. [PMID: 22647598 DOI: 10.1073/pnas.1207021109] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The myotubularins are a large family of inositol polyphosphate 3-phosphatases that, despite having common substrates, subsume unique functions in cells that are disparate. The myotubularin family consists of 16 different proteins, 9 members of which possess catalytic activity, dephosphorylating phosphatidylinositol 3-phosphate [PtdIns(3)P] and phosphatidylinositol 3,5-bisphosphate [PtdIns(3,5)P(2)] at the D-3 position. Seven members are inactive because they lack the conserved cysteine residue in the CX(5)R motif required for activity. We studied a subfamily of homologous myotubularins, including myotubularin-related protein 6 (MTMR6), MTMR7, and MTMR8, all of which dimerize with the catalytically inactive MTMR9. Complex formation between the active myotubularins and MTMR9 increases their catalytic activity and alters their substrate specificity, wherein the MTMR6/R9 complex prefers PtdIns(3,5)P(2) as substrate; the MTMR8/R9 complex prefers PtdIns(3)P. MTMR9 increased the enzymatic activity of MTMR6 toward PtdIns(3,5)P(2) by over 30-fold, and enhanced the activity toward PtdIns(3)P by only 2-fold. In contrast, MTMR9 increased the activity of MTMR8 by 1.4-fold and 4-fold toward PtdIns(3,5)P(2) and PtdIns(3)P, respectively. In cells, the MTMR6/R9 complex significantly increases the cellular levels of PtdIns(5)P, the product of PI(3,5)P(2) dephosphorylation, whereas the MTMR8/R9 complex reduces cellular PtdIns(3)P levels. Consequentially, the MTMR6/R9 complex serves to inhibit stress-induced apoptosis and the MTMR8/R9 complex inhibits autophagy.
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Jean S, Cox S, Schmidt EJ, Robinson FL, Kiger A. Sbf/MTMR13 coordinates PI(3)P and Rab21 regulation in endocytic control of cellular remodeling. Mol Biol Cell 2012; 23:2723-40. [PMID: 22648168 PMCID: PMC3395661 DOI: 10.1091/mbc.e12-05-0375] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The MTM phosphatases include poorly defined, catalytically inactive members. Drosophila Sbf, an MTM pseudophosphatase, physically and functionally interacts with class II PI3-kinase, Mtm PI3-phosphatase, and Rab21, each required for macrophage remodeling. Sbf plays dual roles in Mtm PI(3)P turnover and as a Rab21 GEF to coordinate endosomal dynamics. Cells rely on the coordinated regulation of lipid phosphoinositides and Rab GTPases to define membrane compartment fates along distinct trafficking routes. The family of disease-related myotubularin (MTM) phosphoinositide phosphatases includes catalytically inactive members, or pseudophosphatases, with poorly understood functions. We found that Drosophila MTM pseudophosphatase Sbf coordinates both phosphatidylinositol 3-phosphate (PI(3)P) turnover and Rab21 GTPase activation in an endosomal pathway that controls macrophage remodeling. Sbf dynamically interacts with class II phosphatidylinositol 3-kinase and stably recruits Mtm to promote turnover of a PI(3)P subpool essential for endosomal trafficking. Sbf also functions as a guanine nucleotide exchange factor that promotes Rab21 GTPase activation associated with PI(3)P endosomes. Of importance, Sbf, Mtm, and Rab21 function together, along with Rab11-mediated endosomal trafficking, to control macrophage protrusion formation. This identifies Sbf as a critical coordinator of PI(3)P and Rab21 regulation, which specifies an endosomal pathway and cortical control.
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Affiliation(s)
- Steve Jean
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0380, USA
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