1
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Lin WY, Chung WY, Muallem S. The tether function of the anoctamins. Cell Calcium 2024; 121:102875. [PMID: 38701708 PMCID: PMC11166512 DOI: 10.1016/j.ceca.2024.102875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/17/2024] [Accepted: 03/20/2024] [Indexed: 05/05/2024]
Abstract
The core functions of the anoctamins are Cl- channel activity and phosphatidylserine (and perhaps other lipids) scrambling. These functions have been extensively studied in various tissues and cells. However, another function of the anoctamins that is less recognized and minimally explored is as tethers at membrane contact sites. This short review aims to examine evidence supporting the localization of the anoctamins at membrane contact sites, their tether properties, and their functions as tethers.
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Affiliation(s)
- Wei-Yin Lin
- From the Epithelial Signaling and Transport Section, National Institute of Dental Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Woo Young Chung
- From the Epithelial Signaling and Transport Section, National Institute of Dental Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shmuel Muallem
- From the Epithelial Signaling and Transport Section, National Institute of Dental Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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2
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Ousingsawat J, Talbi K, Gómez-Martín H, Koy A, Fernández-Jaén A, Tekgül H, Serdaroğlu E, Schreiber R, Ortigoza-Escobar JD, Kunzelmann K. Broadening the clinical spectrum: molecular mechanisms and new phenotypes of ANO3-dystonia. Brain 2024; 147:1982-1995. [PMID: 38079528 DOI: 10.1093/brain/awad412] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 11/02/2023] [Accepted: 11/18/2023] [Indexed: 06/04/2024] Open
Abstract
Anoctamin 3 (ANO3) belongs to a family of transmembrane proteins that form phospholipid scramblases and ion channels. A large number of ANO3 variants were identified as the cause of craniocervical dystonia, but the underlying pathogenic mechanisms remain obscure. It was suggested that ANO3 variants may dysregulate intracellular Ca2+ signalling, as variants in other Ca2+ regulating proteins like hippocalcin were also identified as a cause of dystonia. In this study, we conducted a comprehensive evaluation of the clinical, radiological and molecular characteristics of four individuals from four families who carried heterozygous variants in ANO3. The median age at follow-up was 6.6 years (ranging from 3.8 to 8.7 years). Three individuals presented with hypotonia and motor developmental delay. Two patients exhibited generalized progressive dystonia, while one patient presented with paroxysmal dystonia. Additionally, another patient exhibited early dyskinetic encephalopathy. One patient underwent bipallidal deep brain stimulation (DBS) and showed a mild but noteworthy response, while another patient is currently being considered for DBS treatment. Neuroimaging analysis of brain MRI studies did not reveal any specific abnormalities. The molecular spectrum included two novel ANO3 variants (V561L and S116L) and two previously reported ANO3 variants (A599D and S651N). As anoctamins are suggested to affect intracellular Ca2+ signals, we compared Ca2+ signalling and activation of ion channels in cells expressing wild-type ANO3 and cells expressing anoctamin variants. Novel V561L and S116L variants were compared with previously reported A599D and S651N variants and with wild-type ANO3 expressed in fibroblasts isolated from patients or when overexpressed in HEK293 cells. We identified ANO3 as a Ca2+-activated phospholipid scramblase that also conducts ions. Impaired Ca2+ signalling and compromised activation of Ca2+-dependent K+ channels were detected in cells expressing ANO3 variants. In the brain striatal cells of affected patients, impaired activation of KCa3.1 channels due to compromised Ca2+ signals may lead to depolarized membrane voltage and neuronal hyperexcitability and may also lead to reduced cellular viability, as shown in the present study. In conclusion, our study reveals the association between ANO3 variants and paroxysmal dystonia, representing the first reported link between these variants and this specific dystonic phenotype. We demonstrate that ANO3 functions as a Ca2+-activated phospholipid scramblase and ion channel; cells expressing ANO3 variants exhibit impaired Ca2+ signalling and compromised activation of Ca2+-dependent K+ channels. These findings provide a mechanism for the observed clinical manifestations and highlight the importance of ANO3 for neuronal excitability and cellular viability.
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Affiliation(s)
| | - Khaoula Talbi
- Physiological Institute, University of Regensburg, D-93053 Regensburg, Germany
| | - Hilario Gómez-Martín
- Pediatric Neurology Unit, Department of Pediatrics, Hospital Universitario de Salamanca, 37007 Castilla y Leon, Spain
| | - Anne Koy
- Centre for Rare Diseases, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Köln, Germany
- Department of Pediatrics, Faculty of Medicine and University, Hospital Cologne, University of Cologne, 50931 Köln, Germany
| | - Alberto Fernández-Jaén
- Department of Pediatric Neurology, Hospital Universitario Quirónsalud, 28223 Pozuelo de Alarcón, Madrid, Spain
- School of Medicine, Universidad Europea De Madrid, 28670 Villaviciosa de Odón, Madrid, Spain
| | - Hasan Tekgül
- Division of Pediatric Neurology, Ege Children's Hospital, Ege University Medical School, 35100 Bornova, Izmir, Turkey
| | - Esra Serdaroğlu
- Department of Pediatric Neurology, Gazi University, Emniyet, 06560 Yenimahalle, Ankara, Turkey
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, D-93053 Regensburg, Germany
| | - Juan Dario Ortigoza-Escobar
- U-703 Centre for Biomedical Research on Rare Diseases (CIBER-ER), Instituto de Salud Carlos III, 08003 Barcelona, Spain
- Movement Disorders Unit, Pediatric Neurology Department, Institut de Recerca Hospital Sant Joan de Déu, 08950 Barcelona, Spain
- European Reference Network for Rare Neurological Diseases (ERN-RND), 08950 Barcelona, Spain
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, D-93053 Regensburg, Germany
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3
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Schreiber R, Ousingsawat J, Kunzelmann K. The anoctamins: Structure and function. Cell Calcium 2024; 120:102885. [PMID: 38642428 DOI: 10.1016/j.ceca.2024.102885] [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: 02/21/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/22/2024]
Abstract
When activated by increase in intracellular Ca2+, anoctamins (TMEM16 proteins) operate as phospholipid scramblases and as ion channels. Anoctamin 1 (ANO1) is the Ca2+-activated epithelial anion-selective channel that is coexpressed together with the abundant scramblase ANO6 and additional intracellular anoctamins. In salivary and pancreatic glands, ANO1 is tightly packed in the apical membrane and secretes Cl-. Epithelia of airways and gut use cystic fibrosis transmembrane conductance regulator (CFTR) as an apical Cl- exit pathway while ANO1 supports Cl- secretion mainly by facilitating activation of luminal CFTR and basolateral K+ channels. Under healthy conditions ANO1 modulates intracellular Ca2+ signals by tethering the endoplasmic reticulum, and except of glands its direct secretory contribution as Cl- channel might be small, compared to CFTR. In the kidneys ANO1 supports proximal tubular acid secretion and protein reabsorption and probably helps to excrete HCO3-in the collecting duct epithelium. However, under pathological conditions as in polycystic kidney disease, ANO1 is strongly upregulated and may cause enhanced proliferation and cyst growth. Under pathological condition, ANO1 and ANO6 are upregulated and operate as secretory channel/phospholipid scramblases, partly by supporting Ca2+-dependent processes. Much less is known about the role of other epithelial anoctamins whose potential functions are discussed in this review.
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Affiliation(s)
- Rainer Schreiber
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany
| | - Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany.
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4
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Kunzelmann K, Ousingsawat J, Schreiber R. VSI: The anoctamins: Structure and function: "Intracellular" anoctamins. Cell Calcium 2024; 120:102888. [PMID: 38657371 DOI: 10.1016/j.ceca.2024.102888] [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: 02/20/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/26/2024]
Abstract
Plasma membrane localized anoctamin 1, 2 and 6 (TMEM16A, B, F) have been examined in great detail with respect to structure and function, but much less is known about the other seven intracellular members of this exciting family of proteins. This is probably due to their limited accessibility in intracellular membranous compartments, such as the endoplasmic reticulum (ER) or endosomes. However, these so-called intracellular anoctamins are also found in the plasma membrane (PM) which adds to the confusion regarding their cellular role. Probably all intracellular anoctamins except of ANO8 operate as intracellular phospholipid (PL) scramblases, allowing for Ca2+-activated, passive transport of phospholipids like phosphatidylserine between both membrane leaflets. Probably all of them also conduct ions, which is probably part of their physiological function. In this brief overview, we summarize key findings on the biological functions of ANO3, 4, 5, 7, 8, 9 and 10 (TMEM16C, D, E, G, H, J, K) that are gradually coming to light. Compartmentalized regulation of intracellular Ca2+ signals, tethering of the ER to specific PM contact sites, and control of intracellular vesicular trafficking appear to be some of the functions of intracellular anoctamins, while loss of function and abnormal expression are the cause for various diseases.
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Affiliation(s)
- Karl Kunzelmann
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany.
| | - Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany
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5
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Norris AC, Mansueto AJ, Jimenez M, Yazlovitskaya EM, Jain BK, Graham TR. Flipping the script: Advances in understanding how and why P4-ATPases flip lipid across membranes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119700. [PMID: 38382846 DOI: 10.1016/j.bbamcr.2024.119700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 11/15/2023] [Accepted: 02/16/2024] [Indexed: 02/23/2024]
Abstract
Type IV P-type ATPases (P4-ATPases) are a family of transmembrane enzymes that translocate lipid substrates from the outer to the inner leaflet of biological membranes and thus create an asymmetrical distribution of lipids within membranes. On the cellular level, this asymmetry is essential for maintaining the integrity and functionality of biological membranes, creating platforms for signaling events and facilitating vesicular trafficking. On the organismal level, this asymmetry has been shown to be important in maintaining blood homeostasis, liver metabolism, neural development, and the immune response. Indeed, dysregulation of P4-ATPases has been linked to several diseases; including anemia, cholestasis, neurological disease, and several cancers. This review will discuss the evolutionary transition of P4-ATPases from cation pumps to lipid flippases, the new lipid substrates that have been discovered, the significant advances that have been achieved in recent years regarding the structural mechanisms underlying the recognition and flipping of specific lipids across biological membranes, and the consequences of P4-ATPase dysfunction on cellular and physiological functions. Additionally, we emphasize the requirement for additional research to comprehensively understand the involvement of flippases in cellular physiology and disease and to explore their potential as targets for therapeutics in treating a variety of illnesses. The discussion in this review will primarily focus on the budding yeast, C. elegans, and mammalian P4-ATPases.
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Affiliation(s)
- Adriana C Norris
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Mariana Jimenez
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Bhawik K Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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6
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Lowry AJ, Liang P, Wan YCS, Pei ZM, Yang H, Zhang Y. TMEM16 and TMEM63/OSCA proteins share a conserved potential to permeate ions and phospholipids. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.04.578431. [PMID: 38370744 PMCID: PMC10871192 DOI: 10.1101/2024.02.04.578431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
The calcium-activated TMEM16 proteins and the mechanosensitive/osmolarity-activated OSCA/TMEM63 proteins belong to the Transmembrane Channel/Scramblase (TCS) superfamily. Within the superfamily, OSCA/TMEM63 proteins, as well as TMEM16A and TMEM16B, likely function solely as ion channels. However, the remaining TMEM16 members, including TMEM16F, maintain an additional function as scramblases, rapidly exchanging phospholipids between leaflets of the membrane. Although recent studies have advanced our understanding of TCS structure-function relationships, the molecular determinants of TCS ion and lipid permeation remain unclear. Here we show that single lysine mutations in transmembrane helix (TM) 4 allow non-scrambling TCS members to permeate phospholipids. This study highlights the key role of TM 4 in controlling TCS ion and lipid permeation and offers novel insights into the evolution of the TCS superfamily, suggesting that, like TMEM16s, the OSCA/TMEM63 family maintains a conserved potential to permeate ions and phospholipids.
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Affiliation(s)
- Augustus J Lowry
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Pengfei Liang
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Y C Serena Wan
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Zhen-Ming Pei
- Department of Biology, Duke University, Durham, NC 27710, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yang Zhang
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Current address: Shenzhen Bay Laboratory, Guangdong 518106, China
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7
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Sieler M, Dittmar T. Cell Fusion and Syncytia Formation in Cancer. Results Probl Cell Differ 2024; 71:433-465. [PMID: 37996689 DOI: 10.1007/978-3-031-37936-9_20] [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] [Indexed: 11/25/2023]
Abstract
The natural phenomenon of cell-cell fusion does not only take place in physiological processes, such as placentation, myogenesis, or osteoclastogenesis, but also in pathophysiological processes, such as cancer. More than a century ago postulated, today the hypothesis that the fusion of cancer cells with normal cells leads to the formation of cancer hybrid cells with altered properties is in scientific consensus. Some studies that have investigated the mechanisms and conditions for the fusion of cancer cells with other cells, as well as studies that have characterized the resulting cancer hybrid cells, are presented in this review. Hypoxia and the cytokine TNFα, for example, have been found to promote cell fusion. In addition, it has been found that both the protein Syncytin-1, which normally plays a role in placentation, and phosphatidylserine signaling on the cell membrane are involved in the fusion of cancer cells with other cells. In human cancer, cancer hybrid cells were detected not only in the primary tumor, but also in the circulation of patients as so-called circulating hybrid cells, where they often correlated with a worse outcome. Although some data are available, the questions of how and especially why cancer cells fuse with other cells are still not fully answered.
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Affiliation(s)
- Mareike Sieler
- Institute of Immunology, Center for Biomedical Education and Research (ZBAF), University of Witten/Herdecke, Witten, Germany.
| | - Thomas Dittmar
- Institute of Immunology, Center for Biomedical Education and Research (ZBAF), University of Witten/Herdecke, Witten, Germany
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8
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Nguyen DM, Chen TY. Structure and Function of Calcium-Activated Chloride Channels and Phospholipid Scramblases in the TMEM16 Family. Handb Exp Pharmacol 2024; 283:153-180. [PMID: 35792944 DOI: 10.1007/164_2022_595] [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] [Indexed: 06/15/2023]
Abstract
The transmembrane protein 16 (TMEM16) family consists of Ca2+-activated chloride channels and phospholipid scramblases. Ten mammalian TMEM16 proteins, TMEM16A-K (with no TMEM16I), and several non-mammalian TMEM16 proteins, such as afTMEM16 and nhTMEM16, have been discovered. All known TMEM16 proteins are homodimeric proteins containing two subunits. Each subunit consists of ten transmembrane helices with Ca2+-binding sites and a single ion-permeation/phospholipid transport pathway. The ion-permeation pathway and the phospholipid transport pathway of TMEM16 proteins have a wide intracellular vestibule, a narrow neck, and a smaller extracellular vestibule. Interestingly, the lining wall of the ion-permeation/phospholipid transport pathway may be formed, at least partially, by membrane phospholipids, though the degree of pore-wall forming by phospholipids likely varies among TMEM16 proteins. Thus, the biophysical properties and activation mechanisms of TMEM16 proteins could differ from each other accordingly. Here we review the current understanding of the structure and function of TMEM16 molecules.
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Affiliation(s)
- Dung Manh Nguyen
- Center for Neuroscience, University of California, Davis, CA, USA.
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Tsung-Yu Chen
- Department of Neurology, Center for Neuroscience, University of California, Davis, CA, USA.
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9
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Doktorova M, Levental I, Heberle FA. Seeing the Membrane from Both Sides Now: Lipid Asymmetry and Its Strange Consequences. Cold Spring Harb Perspect Biol 2023; 15:a041393. [PMID: 37604588 PMCID: PMC10691478 DOI: 10.1101/cshperspect.a041393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Almost all biomembranes are constructed as lipid bilayers and, in almost all of these, the two opposing monolayers (leaflets) have distinct lipid compositions. This lipid asymmetry arises through the concerted action of a suite of energy-dependent enzymes that maintain living bilayers in a far-from-equilibrium steady-state. Recent discoveries reveal that lipid compositional asymmetry imparts biophysical asymmetries and that this dualistic organization may have major consequences for cellular physiology. Importantly, while transbilayer asymmetry appears to be an essential, near-ubiquitous characteristic of biological membranes, it has been challenging to reproduce in reconstituted or synthetic systems. Although recent methodological developments have overcome some critical challenges, it remains difficult to extrapolate results from available models to biological systems. Concurrently, there are few experimental approaches for targeted, controlled manipulation of lipid asymmetry in living cells. Thus, the biophysical and functional consequences of membrane asymmetry remain almost wholly unexplored. This perspective summarizes the current state of knowledge and highlights emerging themes that are beginning to make inroads into the fundamental question of why life tends toward asymmetry in its bilayers.
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Affiliation(s)
- Milka Doktorova
- Department of Molecular Physiology and Pharmacology, University of Virginia, Center for Membrane and Cell Physiology, Charlottesville, Virginia 22908, USA
| | - Ilya Levental
- Department of Molecular Physiology and Pharmacology, University of Virginia, Center for Membrane and Cell Physiology, Charlottesville, Virginia 22908, USA
| | - Frederick A Heberle
- Department of Chemistry, University of Tennessee Knoxville, Knoxville, Tennessee 37996, USA
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10
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Shan KZ, Le T, Liang P, Dong P, Yang H. Endothelial TMEM16F lipid scramblase regulates angiogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.17.553724. [PMID: 37645870 PMCID: PMC10462142 DOI: 10.1101/2023.08.17.553724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Dynamic loss of lipid asymmetry through the activation of TMEM16 Ca2+-activated lipid scramblases (CaPLSases) has been increasingly recognized as an essential membrane event in a wide range of physiological and pathological processes, including blood coagulation, microparticle release, bone development, pain sensation, cell-cell fusion, and viral infection. Despite the recent implications of TMEM16F CaPLSase in vascular development and endothelial cell-mediated coagulation, its signaling role in endothelial biology remains to be established. Here, we show that endothelial TMEM16F regulates in vitro and in vivo angiogenesis through intracellular signaling. Developmental retinal angiogenesis is significantly impaired in TMEM16F deficient mice, as evidenced by fewer vascular loops and larger loop areas. Consistent with our in vivo observation, TMEM16F siRNA knockdown in human umbilical vein endothelial cells compromises angiogenesis in vitro. We further discovered that TMEM16F knockdown enhances VE-cadherin phosphorylation and reduces its expression. Moreover, TMEM16F knockdown also promotes Src kinase phosphorylation at tyrosine 416, which may be responsible for downregulating VE-cadherin expression. Our study thus uncovers a new biological function of TMEM16F in angiogenesis and provides a potential mechanism for how the CaPLSase regulates angiogenesis through intracellular signaling.
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Affiliation(s)
- Ke Zoe Shan
- Department of Biochemistry, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Trieu Le
- Department of Biochemistry, Duke University, School of Medicine, Durham, NC 27710, USA
- Curreent address: Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Pengfei Liang
- Department of Biochemistry, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Ping Dong
- Department of Biochemistry, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University, School of Medicine, Durham, NC 27710, USA
- Curreent address: Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
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11
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Filep JG. Two to tango: endothelial cell TMEM16 scramblases drive coagulation and thrombosis. J Clin Invest 2023; 133:170643. [PMID: 37259922 DOI: 10.1172/jci170643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
Endothelial cells form a constitutively anticoagulant surface under homeostasis. While loss of this anticoagulant property is a hallmark of many cardiovascular diseases, the molecular mechanisms underlying the procoagulant transition remain incompletely understood. In this issue of the JCI, Schmaier et al. identify the phospholipid scramblases TMEM16E and TMEM16F, which support endothelial procoagulant activity through phosphatidylserine (PS) externalization. Genetic deletion of TMEM16E or TMEM16F or treatment with TMEM16 inhibitors prevented PS externalization and reduced fibrin formation in the vessel wall independently of platelets in a murine laser-injury model of thrombosis. These findings reveal a role for endothelial TMEM16E in thrombosis and identify TMEM16E as a potential therapeutic target for preventing thrombus formation.
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Affiliation(s)
- János G Filep
- Department of Pathology and Cell Biology, University of Montreal, Montreal, Quebec, Canada
- Research Center, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada
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12
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Schmaier AA, Anderson PF, Chen SM, El-Darzi E, Aivasovsky I, Kaushik MP, Sack KD, Hartzell HC, Parikh SM, Flaumenhaft R, Schulman S. TMEM16E regulates endothelial cell procoagulant activity and thrombosis. J Clin Invest 2023; 133:e163808. [PMID: 36951953 PMCID: PMC10231993 DOI: 10.1172/jci163808] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/22/2023] [Indexed: 03/24/2023] Open
Abstract
Endothelial cells (ECs) normally form an anticoagulant surface under physiological conditions, but switch to support coagulation following pathogenic stimuli. This switch promotes thrombotic cardiovascular disease. To generate thrombin at physiologic rates, coagulation proteins assemble on a membrane containing anionic phospholipid, most notably phosphatidylserine (PS). PS can be rapidly externalized to the outer cell membrane leaflet by phospholipid "scramblases," such as TMEM16F. TMEM16F-dependent PS externalization is well characterized in platelets. In contrast, how ECs externalize phospholipids to support coagulation is not understood. We employed a focused genetic screen to evaluate the contribution of transmembrane phospholipid transport on EC procoagulant activity. We identified 2 TMEM16 family members, TMEM16F and its closest paralog, TMEM16E, which were both required to support coagulation on ECs via PS externalization. Applying an intravital laser-injury model of thrombosis, we observed, unexpectedly, that PS externalization was concentrated at the vessel wall, not on platelets. TMEM16E-null mice demonstrated reduced vessel-wall-dependent fibrin formation. The TMEM16 inhibitor benzbromarone prevented PS externalization and EC procoagulant activity and protected mice from thrombosis without increasing bleeding following tail transection. These findings indicate the activated endothelial surface is a source of procoagulant phospholipid contributing to thrombus formation. TMEM16 phospholipid scramblases may be a therapeutic target for thrombotic cardiovascular disease.
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Affiliation(s)
- Alec A. Schmaier
- Division of Cardiovascular Medicine and
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | | | | | - Emale El-Darzi
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | | | | | - Kelsey D. Sack
- Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - H. Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Samir M. Parikh
- Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
- Division of Nephrology and Departments of Internal Medicine and Pharmacology, University of Texas Southwestern Medical School, Dallas, Texas, USA
| | - Robert Flaumenhaft
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
- Division of Hematology and Hematologic Malignancies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Sol Schulman
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
- Division of Hematology and Hematologic Malignancies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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13
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Dittmar T, Hass R. Intrinsic signalling factors associated with cancer cell-cell fusion. Cell Commun Signal 2023; 21:68. [PMID: 37016404 PMCID: PMC10071245 DOI: 10.1186/s12964-023-01085-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/21/2023] [Indexed: 04/06/2023] Open
Abstract
Cellular fusion e.g. between cancer cells and normal cells represents a stepwise process that is tightly regulated. During a pre-hybrid preparation program somatic cells and/or cancer cells are promoted to a pro-fusogenic state as a prerequisite to prepare a fusion process. A pro-fusogenic state requires significant changes including restructure of the cytoskeleton, e.g., by the formation of F-actin. Moreover, distinct plasma membrane lipids such as phosphatidylserine play an important role during cell fusion. In addition, the expression of distinct fusogenic factors such as syncytins and corresponding receptors are of fundamental importance to enable cellular mergers. Subsequent hybrid formation and fusion are followed by a post-hybrid selection process. Fusion among normal cells is important and often required during organismal development. Cancer cells fusion appears more rarely and is associated with the generation of new cancer hybrid cell populations. These cancer hybrid cells contribute to an elevated tumour plasticity by altered metastatic behaviour, changes in therapeutic and apoptotic responses, and even in the formation of cancer stem/ initiating cells. While many parts within this multi-step cascade are still poorly understood, this review article predominantly focusses on the intracellular necessities for fusion among cancer cells or with other cell populations of the tumour microenvironment. Video Abstract.
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Affiliation(s)
- Thomas Dittmar
- Institute of Immunology, Centre for Biomedical Education and Research (ZBAF), Witten/Herdecke University, Stockumer Str. 10, 58448, Witten, Germany.
| | - Ralf Hass
- Biochemistry and Tumor Biology Laboratory, Department of Obstetrics and Gynaecology, Hannover Medical School, 30625, Hannover, Germany.
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14
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Cell surface-bound La protein regulates the cell fusion stage of osteoclastogenesis. Nat Commun 2023; 14:616. [PMID: 36739273 PMCID: PMC9899215 DOI: 10.1038/s41467-023-36168-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/16/2023] [Indexed: 02/06/2023] Open
Abstract
Multinucleated osteoclasts, essential for skeletal remodeling in health and disease, are formed by the fusion of osteoclast precursors, where each fusion event raises their bone-resorbing activity. Here we show that the nuclear RNA chaperone, La protein has an additional function as an osteoclast fusion regulator. Monocyte-to-osteoclast differentiation starts with a drastic decrease in La levels. As fusion begins, La reappears as a low molecular weight species at the osteoclast surface, where it promotes fusion. La's role in promoting osteoclast fusion is independent of canonical La-RNA interactions and involves direct interactions between La and Annexin A5, which anchors La to transiently exposed phosphatidylserine at the surface of fusing osteoclasts. Disappearance of cell-surface La, and the return of full length La to the nuclei of mature, multinucleated osteoclasts, acts as an off switch of their fusion activity. Targeting surface La in a novel explant model of fibrous dysplasia inhibits excessive osteoclast formation characteristic of this disease, highlighting La's potential as a therapeutic target.
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15
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Savarese M, Jokela M, Udd B. Distal myopathy. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:497-519. [PMID: 37562883 DOI: 10.1016/b978-0-323-98818-6.00002-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Distal myopathies are a group of genetic, primary muscle diseases. Patients develop progressive weakness and atrophy of the muscles of forearm, hands, lower leg, or feet. Currently, over 20 different forms, presenting a variable age of onset, clinical presentation, disease progression, muscle involvement, and histological findings, are known. Some of them are dominant and some recessive. Different variants in the same gene are often associated with either dominant or recessive forms, although there is a lack of a comprehensive understanding of the genotype-phenotype correlations. This chapter provides a description of the clinicopathologic and genetic aspects of distal myopathies emphasizing known etiologic and pathophysiologic mechanisms.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Manu Jokela
- Neuromuscular Research Center, Department of Neurology, Tampere University and University Hospital, Tampere, Finland; Division of Clinical Neurosciences, Department of Neurology, Turku University Hospital, Turku, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland; Neuromuscular Research Center, Department of Neurology, Tampere University and University Hospital, Tampere, Finland; Department of Neurology, Vaasa Central Hospital, Vaasa, Finland.
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16
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Arndt M, Alvadia C, Straub MS, Clerico Mosina V, Paulino C, Dutzler R. Structural basis for the activation of the lipid scramblase TMEM16F. Nat Commun 2022; 13:6692. [PMID: 36335104 PMCID: PMC9637102 DOI: 10.1038/s41467-022-34497-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022] Open
Abstract
TMEM16F, a member of the conserved TMEM16 family, plays a central role in the initiation of blood coagulation and the fusion of trophoblasts. The protein mediates passive ion and lipid transport in response to an increase in intracellular Ca2+. However, the mechanism of how the protein facilitates both processes has remained elusive. Here we investigate the basis for TMEM16F activation. In a screen of residues lining the proposed site of conduction, we identify mutants with strongly activating phenotype. Structures of these mutants determined herein by cryo-electron microscopy show major rearrangements leading to the exposure of hydrophilic patches to the membrane, whose distortion facilitates lipid diffusion. The concomitant opening of a pore promotes ion conduction in the same protein conformation. Our work has revealed a mechanism that is distinct for this branch of the family and that will aid the development of a specific pharmacology for a promising drug target.
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Affiliation(s)
- Melanie Arndt
- grid.7400.30000 0004 1937 0650Department of Biochemistry University of Zurich, Winterthurer Str. 190, CH-8057 Zurich, Switzerland
| | - Carolina Alvadia
- grid.7400.30000 0004 1937 0650Department of Biochemistry University of Zurich, Winterthurer Str. 190, CH-8057 Zurich, Switzerland
| | - Monique S. Straub
- grid.7400.30000 0004 1937 0650Department of Biochemistry University of Zurich, Winterthurer Str. 190, CH-8057 Zurich, Switzerland
| | - Vanessa Clerico Mosina
- grid.4830.f0000 0004 0407 1981Department of Structural Biology and Membrane Enzymology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Cristina Paulino
- grid.4830.f0000 0004 0407 1981Department of Structural Biology and Membrane Enzymology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Raimund Dutzler
- grid.7400.30000 0004 1937 0650Department of Biochemistry University of Zurich, Winterthurer Str. 190, CH-8057 Zurich, Switzerland
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17
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Li X, Wang L, Wang H, Qin A, Qin X. Ano5 modulates calcium signaling during bone homeostasis in gnathodiaphyseal dysplasia. NPJ Genom Med 2022; 7:48. [PMID: 35982081 PMCID: PMC9388649 DOI: 10.1038/s41525-022-00312-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 06/29/2022] [Indexed: 11/22/2022] Open
Abstract
ANO5 encodes transmembrane protein 16E (TMEM16E), an intracellular calcium-activated chloride channel in the endoplasmic reticulum. Mutations in ANO5 are associated with gnathodiaphyseal dysplasia (GDD), a skeletal disorder causing the jaw deformity and long bone fractures. However, the coordinated mechanism by which ANO5 mediates bone homeostasis in GDD remains poorly defined. Here, we show that ablation of Ano5 reduced intracellular calcium transients, leading to defects in osteogenesis and osteoclastogenesis and thus bone dysplasia. We found a causative de novo ANO5 frameshift insertion mutation (p.L370_A371insDYWRLNSTCL) in a GDD family with osteopenia, accompanied by a decrease in TMEM16E expression and impaired RANKL-induced intracellular calcium ([Ca2+]i) oscillations in osteoclasts. Moreover, using Ano5 knockout (KO) mice, we found that they exhibited low bone volume, abnormal calcium deposits, and defective osteoblast and osteoclast differentiation. We also showed that Ano5 deletion in mice significantly diminished [Ca2+]i oscillations in both osteoblasts and osteoclasts, which resulted in reduced WNT/β-Catenin and RANKL-NFATc1 signaling, respectively. Osteoanabolic treatment of parathyroid hormone was effective in enhancing bone strength in Ano5 KO mice. Consequently, these data demonstrate that Ano5 positively modulates bone homeostasis via calcium signaling in GDD.
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Affiliation(s)
- Xin Li
- Department of Oral and Maxillofacial Head and Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology and Shanghai Research Institute of Stomatology, 200011, Shanghai, China
| | - Lei Wang
- Department of Oral and Maxillofacial Surgery, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, 510182, Guangzhou, Guangdong, China
| | - Hongwei Wang
- Department of Oral and Craniomaxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
| | - An Qin
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China.
| | - Xingjun Qin
- Department of Oral and Maxillofacial Head and Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology and Shanghai Research Institute of Stomatology, 200011, Shanghai, China.
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18
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Rodriguez TC, Zhong L, Simpson H, Gleason E. Reduced Expression of TMEM16A Impairs Nitric Oxide-Dependent Cl− Transport in Retinal Amacrine Cells. Front Cell Neurosci 2022; 16:937060. [PMID: 35966201 PMCID: PMC9363626 DOI: 10.3389/fncel.2022.937060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
Postsynaptic cytosolic Cl− concentration determines whether GABAergic and glycinergic synapses are inhibitory or excitatory. We have shown that nitric oxide (NO) initiates the release of Cl− from acidic internal stores into the cytosol of retinal amacrine cells (ACs) thereby elevating cytosolic Cl−. In addition, we found that cystic fibrosis transmembrane conductance regulator (CFTR) expression and Ca2+ elevations are necessary for the transient effects of NO on cytosolic Cl− levels, but the mechanism remains to be elucidated. Here, we investigated the involvement of TMEM16A as a possible link between Ca2+ elevations and cytosolic Cl− release. TMEM16A is a Ca2+-activated Cl− channel that is functionally coupled with CFTR in epithelia. Both proteins are also expressed in neurons. Based on this and its Ca2+ dependence, we test the hypothesis that TMEM16A participates in the NO-dependent elevation in cytosolic Cl− in ACs. Chick retina ACs express TMEM16A as shown by Western blot analysis, single-cell PCR, and immunocytochemistry. Electrophysiology experiments demonstrate that TMEM16A functions in amacrine cells. Pharmacological inhibition of TMEM16A with T16inh-AO1 reduces the NO-dependent Cl− release as indicated by the diminished shift in the reversal potential of GABAA receptor-mediated currents. We confirmed the involvement of TMEM16A in the NO-dependent Cl− release using CRISPR/Cas9 knockdown of TMEM16A. Two different modalities targeting the gene for TMEM16A (ANO1) were tested in retinal amacrine cells: an all-in-one plasmid vector and crRNA/tracrRNA/Cas9 ribonucleoprotein. The all-in-one CRISPR/Cas9 modality did not change the expression of TMEM16A protein and produced no change in the response to NO. However, TMEM16A-specific crRNA/tracrRNA/Cas9 ribonucleoprotein effectively reduces both TMEM16A protein levels and the NO-dependent shift in the reversal potential of GABA-gated currents. These results show that TMEM16A plays a role in the NO-dependent Cl− release from retinal ACs.
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19
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Depuydt CE, Goosens V, Janky R, D’Hondt A, De Bleecker JL, Noppe N, Derveaux S, Thal DR, Claeys KG. Unraveling the Molecular Basis of the Dystrophic Process in Limb-Girdle Muscular Dystrophy LGMD-R12 by Differential Gene Expression Profiles in Diseased and Healthy Muscles. Cells 2022; 11:cells11091508. [PMID: 35563815 PMCID: PMC9104122 DOI: 10.3390/cells11091508] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/19/2022] [Accepted: 04/29/2022] [Indexed: 11/28/2022] Open
Abstract
Limb-girdle muscular dystrophy R12 (LGMD-R12) is caused by two mutations in anoctamin-5 (ANO5). Our aim was to identify genes and pathways that underlie LGMD-R12 and explain differences in the molecular predisposition and susceptibility between three thigh muscles that are severely (semimembranosus), moderately (vastus lateralis) or mildly (rectus femoris) affected in this disease. We performed transcriptomics on these three muscles in 16 male LGMD-R12 patients and 15 age-matched male controls. Our results showed that LGMD-R12 dystrophic muscle is associated with the expression of genes indicative of fibroblast and adipocyte replacement, such as fibroadipogenic progenitors and immune cell infiltration, while muscle protein synthesis and metabolism were downregulated. Muscle degeneration was associated with an increase in genes involved in muscle injury and inflammation, and muscle repair/regeneration. Baseline differences between muscles in healthy individuals indicated that muscles that are the most affected by LGMD-R12 have the lowest expression of transcription factor networks involved in muscle (re)generation and satellite stem cell activation. Instead, they show relative high levels of fetal/embryonic myosins, all together indicating that muscles differ in their baseline regenerative potential. To conclude, we profiled the gene expression landscape in LGMD-R12, identified baseline differences in expression levels between differently affected muscles and characterized disease-associated changes.
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Affiliation(s)
- Christophe E. Depuydt
- Laboratory for Muscle Diseases and Neuropathies, Department of Neurosciences, KU Leuven, and Leuven Brain Institute (LBI), Herestraat 49, 3000 Leuven, Belgium;
| | - Veerle Goosens
- Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium; (V.G.); (N.N.)
| | - Rekin’s Janky
- VIB Nucleomics Core, Herestraat 49, 3000 Leuven, Belgium; (R.J.); (S.D.)
| | - Ann D’Hondt
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium;
| | - Jan L. De Bleecker
- Department of Neurology, University Hospital Gent, Corneel Heymanslaan 10, 9000 Gent, Belgium;
| | - Nathalie Noppe
- Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium; (V.G.); (N.N.)
| | - Stefaan Derveaux
- VIB Nucleomics Core, Herestraat 49, 3000 Leuven, Belgium; (R.J.); (S.D.)
| | - Dietmar R. Thal
- Department of Pathology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium;
- Laboratory for Neuropathology, Department of Imaging and Pathology, KU Leuven, and Leuven Brain Institute (LBI), Herestraat 49, 3000 Leuven, Belgium
| | - Kristl G. Claeys
- Laboratory for Muscle Diseases and Neuropathies, Department of Neurosciences, KU Leuven, and Leuven Brain Institute (LBI), Herestraat 49, 3000 Leuven, Belgium;
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium;
- Correspondence: ; Tel.: +32-16-344280; Fax: +32-16-344285
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20
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Grifell-Junyent M, Baum JF, Välimets S, Herrmann A, Paulusma CC, López-Marqués RL, Günther Pomorski T. CDC50A is required for aminophospholipid transport and cell fusion in mouse C2C12 myoblasts. J Cell Sci 2022; 135:jcs258649. [PMID: 34664668 PMCID: PMC10405909 DOI: 10.1242/jcs.258649] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 09/02/2021] [Indexed: 11/20/2022] Open
Abstract
Myoblast fusion is essential for the formation of multinucleated muscle fibers and is promoted by transient changes in the plasma membrane lipid distribution. However, little is known about the lipid transporters regulating these dynamic changes. Here, we show that proliferating myoblasts exhibit an aminophospholipid flippase activity that is downregulated during differentiation. Deletion of the P4-ATPase flippase subunit CDC50A (also known as TMEM30A) results in loss of the aminophospholipid flippase activity and compromises actin remodeling, RAC1 GTPase membrane targeting and cell fusion. In contrast, deletion of the P4-ATPase ATP11A affects aminophospholipid uptake without having a strong impact on cell fusion. Our results demonstrate that myoblast fusion depends on CDC50A and may involve multiple CDC50A-dependent P4-ATPases that help to regulate actin remodeling.
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Affiliation(s)
- Marta Grifell-Junyent
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Julia F. Baum
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Silja Välimets
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Andreas Herrmann
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
| | - Coen C. Paulusma
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Amsterdam Gastroenterology and Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Rosa L. López-Marqués
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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21
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Scramblases as Regulators of Proteolytic ADAM Function. MEMBRANES 2022; 12:membranes12020185. [PMID: 35207106 PMCID: PMC8880048 DOI: 10.3390/membranes12020185] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/25/2022] [Accepted: 02/02/2022] [Indexed: 11/16/2022]
Abstract
Proteolytic ectodomain release is a key mechanism for regulating the function of many cell surface proteins. The sheddases ADAM10 and ADAM17 are the best-characterized members of the family of transmembrane disintegrin-like metalloproteinase. Constitutive proteolytic activities are low but can be abruptly upregulated via inside-out signaling triggered by diverse activating events. Emerging evidence indicates that the plasma membrane itself must be assigned a dominant role in upregulation of sheddase function. Data are discussed that tentatively identify phospholipid scramblases as central players during these events. We propose that scramblase-dependent externalization of the negatively charged phospholipid phosphatidylserine (PS) plays an important role in the final activation step of ADAM10 and ADAM17. In this manuscript, we summarize the current knowledge on the interplay of cell membrane changes, PS exposure, and proteolytic activity of transmembrane proteases as well as the potential consequences in the context of immune response, infection, and cancer. The novel concept that scramblases regulate the action of ADAM-proteases may be extendable to other functional proteins that act at the cell surface.
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22
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Foltz S, Wu F, Ghazal N, Kwong JQ, Hartzell HC, Choo HJ. Sex differences in the involvement of skeletal and cardiac muscles in myopathic Ano5-/- mice. Am J Physiol Cell Physiol 2022; 322:C283-C295. [PMID: 35020501 PMCID: PMC8836717 DOI: 10.1152/ajpcell.00350.2021] [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: 09/22/2021] [Revised: 12/14/2021] [Accepted: 01/07/2022] [Indexed: 02/03/2023]
Abstract
Limb-girdle muscular dystrophy R12 (LGMD-R12) is caused by recessive mutations in the Anoctamin-5 gene (ANO5, TMEM16E). Although ANO5 myopathy is not X-chromosome linked, we performed a meta-analysis of the research literature and found that three-quarters of patients with LGMD-R12 are males. Females are less likely to present with moderate to severe skeletal muscle and/or cardiac pathology. Because these sex differences could be explained in several ways, we compared males and females in a mouse model of LGMD-R12. This model recapitulates the sex differences in human LGMD-R12. Only male Ano5-/- mice had elevated serum creatine kinase after exercise and exhibited defective membrane repair after laser injury. In contrast, by these measures, female Ano5-/- mice were indistinguishable from wild type. Despite these differences, both male and female Ano5-/- mice exhibited exercise intolerance. Although exercise intolerance of male mice can be explained by skeletal muscle dysfunction, echocardiography revealed that Ano5-/- female mice had features of cardiomyopathy that may be responsible for their exercise intolerance. These findings heighten concerns that mutations of ANO5 in humans may be linked to cardiac disease.
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Affiliation(s)
- Steven Foltz
- Department of Cell Biology, School of Medicine, Emory University, Atlanta, Georgia
| | - Fang Wu
- Department of Cell Biology, School of Medicine, Emory University, Atlanta, Georgia
| | - Nasab Ghazal
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia
| | - Jennifer Q Kwong
- Department of Cell Biology, School of Medicine, Emory University, Atlanta, Georgia
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia
- Division of Pediatric Cardiology, Department of Pediatrics, School of Medicine, Emory University and Children's Healthcare of Atlanta, Atlanta, Georgia
| | - H Criss Hartzell
- Department of Cell Biology, School of Medicine, Emory University, Atlanta, Georgia
| | - Hyojung J Choo
- Department of Cell Biology, School of Medicine, Emory University, Atlanta, Georgia
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23
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Polymodal Control of TMEM16x Channels and Scramblases. Int J Mol Sci 2022; 23:ijms23031580. [PMID: 35163502 PMCID: PMC8835819 DOI: 10.3390/ijms23031580] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
The TMEM16A/anoctamin-1 calcium-activated chloride channel (CaCC) contributes to a range of vital functions, such as the control of vascular tone and epithelial ion transport. The channel is a founding member of a family of 10 proteins (TMEM16x) with varied functions; some members (i.e., TMEM16A and TMEM16B) serve as CaCCs, while others are lipid scramblases, combine channel and scramblase function, or perform additional cellular roles. TMEM16x proteins are typically activated by agonist-induced Ca2+ release evoked by Gq-protein-coupled receptor (GqPCR) activation; thus, TMEM16x proteins link Ca2+-signalling with cell electrical activity and/or lipid transport. Recent studies demonstrate that a range of other cellular factors—including plasmalemmal lipids, pH, hypoxia, ATP and auxiliary proteins—also control the activity of the TMEM16A channel and its paralogues, suggesting that the TMEM16x proteins are effectively polymodal sensors of cellular homeostasis. Here, we review the molecular pathophysiology, structural biology, and mechanisms of regulation of TMEM16x proteins by multiple cellular factors.
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24
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Leitzke S, Seidel J, Ahrens B, Schreiber R, Kunzelmann K, Sperrhacke M, Bhakdi S, Reiss K. Influence of Anoctamin-4 and -9 on ADAM10 and ADAM17 Sheddase Function. MEMBRANES 2022; 12:membranes12020123. [PMID: 35207044 PMCID: PMC8879676 DOI: 10.3390/membranes12020123] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/04/2023]
Abstract
Ca2+-activated Cl− channels (TMEM16, also known as anoctamins) perform important functions in cell physiology, including modulation of cell proliferation and cancer growth. Many members, including TMEM16F/ANO6, additionally act as Ca2+-activated phospholipid scramblases. We recently presented evidence that ANO6-dependent surface exposure of phosphatidylserine (PS) is pivotal for the disintegrin-like metalloproteases ADAM10 and ADAM17 to exert their sheddase function. Here, we compared the influence of seven ANO family members (ANO1, 4, 5, 6, 7, 9, and 10) on ADAM sheddase activity. Similar to ANO6, overexpression of ANO4 and ANO9 led to increased release of ADAM10 and ADAM17 substrates, such as betacellulin, TGFα, and amphiregulin (AREG), upon ionophore stimulation in HEK cells. Inhibitor experiments indicated that ANO4/ANO9-mediated enhancement of TGFα-cleavage broadened the spectrum of participating metalloproteinases. Annexin V-staining demonstrated increased externalisation of PS in ANO4/ANO9-overexpressing cells. Competition experiments with the soluble PS-headgroup phosphorylserine indicated that the ANO4/ANO9 effects were due to increased PS exposure. Overexpression of ANO4 or ANO9 in human cervical cancer cells (HeLa), enhanced constitutive shedding of the growth factor AREG and increased cell proliferation. We conclude that ANO4 and ANO9, by virtue of their scramblase activity, may play a role as important regulators of ADAM-dependent cellular functions.
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Affiliation(s)
- Sinje Leitzke
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | - Jana Seidel
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | - Björn Ahrens
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany; (R.S.); (K.K.)
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany; (R.S.); (K.K.)
| | - Maria Sperrhacke
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | | | - Karina Reiss
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
- Correspondence:
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25
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Sharma M, Mahajan S, Dhall A, Jassal B, Saluja A, Faruq M, Suri V, Rajan R, Vishnu V. Anoctamin-5 Muscular Dystrophy: Report of Two Cases with Different Phenotypes and Genotypes from the Indian Subcontinent. Neurol India 2022; 70:2169-2173. [DOI: 10.4103/0028-3886.359155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Li H, Xu L, Gao Y, Zuo Y, Yang Z, Zhao L, Chen Z, Guo S, Han R. BVES is a novel interactor of ANO5 and regulates myoblast differentiation. Cell Biosci 2021; 11:222. [PMID: 34963485 PMCID: PMC8715634 DOI: 10.1186/s13578-021-00735-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/17/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anoctamin 5 (ANO5) is a membrane protein belonging to the TMEM16/Anoctamin family and its deficiency leads to the development of limb girdle muscular dystrophy R12 (LGMDR12). However, little has been known about the interactome of ANO5 and its cellular functions. RESULTS In this study, we exploited a proximal labeling approach to identify the interacting proteins of ANO5 in C2C12 myoblasts stably expressing ANO5 tagged with BioID2. Mass spectrometry identified 41 unique proteins including BVES and POPDC3 specifically from ANO5-BioID2 samples, but not from BioID2 fused with ANO6 or MG53. The interaction between ANO5 and BVES was further confirmed by co-immunoprecipitation (Co-IP), and the N-terminus of ANO5 mediated the interaction with the C-terminus of BVES. ANO5 and BVES were co-localized in muscle cells and enriched at the endoplasmic reticulum (ER) membrane. Genome editing-mediated ANO5 or BVES disruption significantly suppressed C2C12 myoblast differentiation with little impact on proliferation. CONCLUSIONS Taken together, these data suggest that BVES is a novel interacting protein of ANO5, involved in regulation of muscle differentiation.
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Affiliation(s)
- Haiwen Li
- Division of Cardiac Surgery, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Li Xu
- Division of Cardiac Surgery, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Yandi Gao
- Division of Cardiac Surgery, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Yuanbojiao Zuo
- Division of Cardiac Surgery, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.,Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Zuocheng Yang
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Lingling Zhao
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Zhiheng Chen
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Shuliang Guo
- Division of Cardiac Surgery, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Renzhi Han
- Division of Cardiac Surgery, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
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27
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Le SC, Liang P, Lowry AJ, Yang H. Gating and Regulatory Mechanisms of TMEM16 Ion Channels and Scramblases. Front Physiol 2021; 12:787773. [PMID: 34867487 PMCID: PMC8640346 DOI: 10.3389/fphys.2021.787773] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/29/2021] [Indexed: 12/30/2022] Open
Abstract
The transmembrane protein 16 (TMEM16) family consists of Ca2+-activated ion channels and Ca2+-activated phospholipid scramblases (CaPLSases) that passively flip-flop phospholipids between the two leaflets of the membrane bilayer. Owing to their diverse functions, TMEM16 proteins have been implicated in various human diseases, including asthma, cancer, bleeding disorders, muscular dystrophy, arthritis, epilepsy, dystonia, ataxia, and viral infection. To understand TMEM16 proteins in health and disease, it is critical to decipher their molecular mechanisms of activation gating and regulation. Structural, biophysical, and computational characterizations over the past decade have greatly advanced the molecular understanding of TMEM16 proteins. In this review, we summarize major structural features of the TMEM16 proteins with a focus on regulatory mechanisms and gating.
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Affiliation(s)
- Son C. Le
- Department of Biochemistry, Duke University Medical Center, Durham, NC, United States
| | - Pengfei Liang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, United States
| | - Augustus J. Lowry
- Department of Biochemistry, Duke University Medical Center, Durham, NC, United States
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, United States
- Department of Neurobiology, Duke University Medical Center, Durham, NC, United States
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28
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Dittmar T, Weiler J, Luo T, Hass R. Cell-Cell Fusion Mediated by Viruses and HERV-Derived Fusogens in Cancer Initiation and Progression. Cancers (Basel) 2021; 13:5363. [PMID: 34771528 PMCID: PMC8582398 DOI: 10.3390/cancers13215363] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/22/2021] [Accepted: 10/24/2021] [Indexed: 12/13/2022] Open
Abstract
Cell fusion is a well-known, but still scarcely understood biological phenomenon, which might play a role in cancer initiation, progression and formation of metastases. Although the merging of two (cancer) cells appears simple, the entire process is highly complex, energy-dependent and tightly regulated. Among cell fusion-inducing and -regulating factors, so-called fusogens have been identified as a specific type of proteins that are indispensable for overcoming fusion-associated energetic barriers and final merging of plasma membranes. About 8% of the human genome is of retroviral origin and some well-known fusogens, such as syncytin-1, are expressed by human (cancer) cells. Likewise, enveloped viruses can enable and facilitate cell fusion due to evolutionarily optimized fusogens, and are also capable to induce bi- and multinucleation underlining their fusion capacity. Moreover, multinucleated giant cancer cells have been found in tumors derived from oncogenic viruses. Accordingly, a potential correlation between viruses and fusogens of human endogenous retroviral origin in cancer cell fusion will be summarized in this review.
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Affiliation(s)
- Thomas Dittmar
- Institute of Immunology, Center for Biomedical Education and Research (ZBAF), Witten/Herdecke University, 58448 Witten, Germany;
| | - Julian Weiler
- Institute of Immunology, Center for Biomedical Education and Research (ZBAF), Witten/Herdecke University, 58448 Witten, Germany;
| | - Tianjiao Luo
- Biochemistry and Tumor Biology Laboratory, Department of Obstetrics and Gynecology, Hannover Medical School, 30625 Hannover, Germany;
| | - Ralf Hass
- Biochemistry and Tumor Biology Laboratory, Department of Obstetrics and Gynecology, Hannover Medical School, 30625 Hannover, Germany;
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29
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Thiruvengadam G, Sreetama SC, Charton K, Hogarth M, Novak JS, Suel-Petat L, Chandra G, Allard B, Richard I, Jaiswal JK. Anoctamin 5 Knockout Mouse Model Recapitulates LGMD2L Muscle Pathology and Offers Insight Into in vivo Functional Deficits. J Neuromuscul Dis 2021; 8:S243-S255. [PMID: 34633328 PMCID: PMC8673513 DOI: 10.3233/jnd-210720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mutations in the Anoctamin 5 (Ano5) gene that result in the lack of expression or function of ANO5 protein, cause Limb Girdle Muscular Dystrophy (LGMD) 2L/R12, and Miyoshi Muscular Dystrophy (MMD3). However, the dystrophic phenotype observed in patient muscles is not uniformly recapitulated by ANO5 knockout in animal models of LGMD2L. Here we describe the generation of a mouse model of LGMD2L generated by targeted out-of-frame deletion of the Ano5 gene. This model shows progressive muscle loss, increased muscle weakness, and persistent bouts of myofiber regeneration without chronic muscle inflammation, which recapitulates the mild to moderate skeletal muscle dystrophy reported in the LGMD2L patients. We show that these features of ANO5 deficient muscle are not associated with a change in the calcium-activated sarcolemmal chloride channel activity or compromised in vivo regenerative myogenesis. Use of this mouse model allows conducting in vivo investigations into the functional role of ANO5 in muscle health and for preclinical therapeutic development for LGMD2L.
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Affiliation(s)
- Girija Thiruvengadam
- Center of Genetic Medicine Research, Children's National Health System, MW Washington, DC
| | - Sen Chandra Sreetama
- Center of Genetic Medicine Research, Children's National Health System, MW Washington, DC
| | - Karine Charton
- Généthon INSERM, U951, INTEGRARE Research Unit, University Paris-Saclay, Evry, France
| | - Marshall Hogarth
- Center of Genetic Medicine Research, Children's National Health System, MW Washington, DC
| | - James S Novak
- Center of Genetic Medicine Research, Children's National Health System, MW Washington, DC.,Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington DC
| | - Laurence Suel-Petat
- Généthon INSERM, U951, INTEGRARE Research Unit, University Paris-Saclay, Evry, France
| | - Goutam Chandra
- Center of Genetic Medicine Research, Children's National Health System, MW Washington, DC
| | - Bruno Allard
- Université Lyon, Université Claude Bernard Lyon 1, Institut NeuroMyoGene, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Lyon, France
| | - Isabelle Richard
- Généthon INSERM, U951, INTEGRARE Research Unit, University Paris-Saclay, Evry, France
| | - Jyoti K Jaiswal
- Center of Genetic Medicine Research, Children's National Health System, MW Washington, DC.,Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington DC
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30
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Hybrid Formation and Fusion of Cancer Cells In Vitro and In Vivo. Cancers (Basel) 2021; 13:cancers13174496. [PMID: 34503305 PMCID: PMC8431460 DOI: 10.3390/cancers13174496] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Cell fusion as a fundamental biological process is required for various physiological processes, including fertilization, placentation, myogenesis, osteoclastogenesis, and wound healing/tissue regeneration. However, cell fusion is also observed during pathophysiological processes like tumor development. Mesenchymal stroma/stem-like cells (MSC) which play an important role within the tumor microenvironment like other cell types such as macrophages can closely interact and hybridize with cancer cells. The formation of cancer hybrid cells can involve various different mechanisms whereby the genomic parts of the hybrid cells require rearrangement to form a new functional hybrid cell. The fusion of cancer cells with neighboring cell types may represent an important mechanism during tumor development since cancer hybrid cells are detectable in various tumor tissues. During this rare event with resulting genomic instability the cancer hybrid cells undergo a post-hybrid selection process (PHSP) to reorganize chromosomes of the two parental nuclei whereby the majority of the hybrid population undergoes cell death. The remaining cancer hybrid cells survive by displaying altered properties within the tumor tissue. Abstract The generation of cancer hybrid cells by intra-tumoral cell fusion opens new avenues for tumor plasticity to develop cancer stem cells with altered properties, to escape from immune surveillance, to change metastatic behavior, and to broaden drug responsiveness/resistance. Genomic instability and chromosomal rearrangements in bi- or multinucleated aneuploid cancer hybrid cells contribute to these new functions. However, the significance of cell fusion in tumorigenesis is controversial with respect to the low frequency of cancer cell fusion events and a clonal advantage of surviving cancer hybrid cells following a post-hybrid selection process. This review highlights alternative processes of cancer hybrid cell development such as entosis, emperipolesis, cannibalism, therapy-induced polyploidization/endoreduplication, horizontal or lateral gene transfer, and focusses on the predominant mechanisms of cell fusion. Based upon new properties of cancer hybrid cells the arising clinical consequences of the subsequent tumor heterogeneity after cancer cell fusion represent a major therapeutic challenge.
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31
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Anion and Cation Permeability of the Mouse TMEM16F Calcium-Activated Channel. Int J Mol Sci 2021; 22:ijms22168578. [PMID: 34445284 PMCID: PMC8395294 DOI: 10.3390/ijms22168578] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/31/2021] [Accepted: 08/04/2021] [Indexed: 12/27/2022] Open
Abstract
TMEM16F is involved in several physiological processes, such as blood coagulation, bone development and virus infections. This protein acts both as a Ca2+-dependent phospholipid scramblase and a Ca2+-activated ion channel but several studies have reported conflicting results about the ion selectivity of the TMEM16F-mediated current. Here, we have performed a detailed side-by-side comparison of the ion selectivity of TMEM16F using the whole-cell and inside-out excised patch configurations to directly compare the results. In inside-out configuration, Ca2+-dependent activation was fast and the TMEM16F-mediated current was activated in a few milliseconds, while in whole-cell recordings full activation required several minutes. We determined the relative permeability between Na+ and Cl¯ (PNa/PCl) using the dilution method in both configurations. The TMEM16F-mediated current was highly nonselective, but there were differences depending on the configuration of the recordings. In whole-cell recordings, PNa/PCl was approximately 0.5, indicating a slight preference for Cl¯ permeation. In contrast, in inside-out experiments the TMEM16F channel showed a higher permeability for Na+ with PNa/PCl reaching 3.7. Our results demonstrate that the time dependence of Ca2+ activation and the ion selectivity of TMEM16F depend on the recording configuration.
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32
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Vázquez J, Lefeuvre C, Escobar RE, Luna Angulo AB, Miranda Duarte A, Delia Hernandez A, Brisset M, Carlier RY, Leturcq F, Durand-Canard MC, Nicolas G, Laforet P, Malfatti E. Phenotypic Spectrum of Myopathies with Recessive Anoctamin-5 Mutations. J Neuromuscul Dis 2021; 7:443-451. [PMID: 32925086 DOI: 10.3233/jnd-200515] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Biallelic variants in Anoctamin 5 (ANO5) gene are causative of limb-girdle muscular dystrophy (LGMD) R12 anoctamin5-related, non-dysferlin Miyoshi-like distal myopathy (MMD3), and asymptomatic hyperCKemia. OBJECTIVE To describe clinic, histologic, genetic and imaging features, of ANO5 mutated patients. METHODS Five patients, four from France (P1, P2, P3 and P4) and one from Mexico (P5), from four families were included. P1 and P2, belonging to group 1, had normal muscle strength; Group 2, P3, P4 and P5, presented with muscular weakness. Muscle strength was measured by manual muscle testing, Medical Research Council (MRC) grades 1/5 to 5/5. Laboratory exams included serum CK levels, nerve conduction studies (NCS)/needle electromyography (EMG), pulmonary function tests, EKG and cardiac ultrasound. ANO5 molecular screening was performed with different approaches. RESULTS Group 1 patients showed myalgias with hyperCKemia or isolated hyperCKemia. Group 2 patients presented with limb-girdle or proximo-distal muscular weakness. Serum CK levels ranged from 897 to 5000 UI/L. Muscle biopsy analysis in P4 and P5 showed subsarcolemmal mitochondrial aggregates. Electron microscopy confirmed mitochondrial proliferation and revealed discontinuity of the sarcolemmal membrane. Muscle MRI showed asymmetrical fibro-fatty substitution predominant in the lower limbs.P1 and P2 were compound heterozygous for c.191dupA (p.Asn64Lysfs*15) and c.1898 + G>A; P3 was homozygous for the c.692G>T. (p.Gly231Val); P4 harbored a novel biallelic homozygous exons 1-7 ANO5 gene deletion, and P5 was homozygous for a c.172 C > T (p.(Arg 58 Trp)) ANO5 pathogenic variant. CONCLUSIONS Our cohort confirms the wide clinical variability and enlarge the genetic spectrum of ANO5-related myopathies.
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Affiliation(s)
- José Vázquez
- Department of Medical Genetics, National Rehabilitation Institute, "Luis Guillermo Ibarra Ibarra", México.,APHP, Department of Neurology, Raymond Poincaré Hospital, North-East-Ile-de-France Neuromuscular Pathology Reference Center, U 1179 INSERM, University Saint Quentin en Yvelines Versailles; Paris-Saclay, France
| | - Claire Lefeuvre
- APHP, Department of Neurology, Raymond Poincaré Hospital, North-East-Ile-de-France Neuromuscular Pathology Reference Center, U 1179 INSERM, University Saint Quentin en Yvelines Versailles; Paris-Saclay, France
| | - Rosa Elena Escobar
- Department of Electromyography and Muscle Dystrophies, National Rehabilitation Institute, "Luis Guillermo Ibarra Ibarra", México
| | | | - Antonio Miranda Duarte
- Department of Medical Genetics, National Rehabilitation Institute, "Luis Guillermo Ibarra Ibarra", México
| | - Alma Delia Hernandez
- Department of Pathology, National Rehabilitation Institute, "Luis Guillermo Ibarra Ibarra", México
| | - Marion Brisset
- APHP, Department of Neurology, Raymond Poincaré Hospital, North-East-Ile-de-France Neuromuscular Pathology Reference Center, U 1179 INSERM, University Saint Quentin en Yvelines Versailles; Paris-Saclay, France
| | - Robert-Yves Carlier
- APHP, GH U. Paris Saclay, DMU Smart Imaging, Department of Radiology, Raymond Poincaré teaching Hospital, 104 Bld R. Poincaré, 92380 Garches, France; U 1179 INSERM, Université Paris-Saclay
| | - France Leturcq
- APHP, Department of Genetics, Cochin Hospital, Paris, France
| | - Marie-Christine Durand-Canard
- APHP, Service of Physiological Explorations Raymond Poincaré Hospital, 104 Bld Raymond Poincaré, 92380 Garches, France
| | - Guillaume Nicolas
- APHP, Department of Neurology, Raymond Poincaré Hospital, North-East-Ile-de-France Neuromuscular Pathology Reference Center, U 1179 INSERM, University Saint Quentin en Yvelines Versailles; Paris-Saclay, France
| | - Pascal Laforet
- APHP, Department of Neurology, Raymond Poincaré Hospital, North-East-Ile-de-France Neuromuscular Pathology Reference Center, U 1179 INSERM, University Saint Quentin en Yvelines Versailles; Paris-Saclay, France
| | - Edoardo Malfatti
- APHP, Department of Neurology, Raymond Poincaré Hospital, North-East-Ile-de-France Neuromuscular Pathology Reference Center, U 1179 INSERM, University Saint Quentin en Yvelines Versailles; Paris-Saclay, France
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33
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Marago I, Roberts M, Roncaroli F, DuPlessis D, Sewry C, Nagaraju S, Limbada F, Marini-Bettolo C, Hudson J, Banerjee S, Newton L, Bukhari M, Chinoy H, Lilleker JB. Limb girdle muscular dystrophy R12 (LGMD 2L, anoctaminopathy) mimicking idiopathic inflammatory myopathy: key points to prevent misdiagnosis. Rheumatology (Oxford) 2021; 61:1645-1650. [PMID: 34264321 DOI: 10.1093/rheumatology/keab553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Diagnosing the idiopathic inflammatory myopathies (IIMs) can be challenging as several conditions, including genetic myopathies such as limb girdle muscular dystrophy type R12 (LGMD 2 l, anoctaminopathy), mimic the presentation. Here we describe learning points identified from review of four patients with LGMD 2 l who were initially incorrectly diagnosed with IIM. Our aim is to provide clinicians working in adult rheumatology services with a toolkit to help identify non-inflammatory presentations of myopathy. METHODS We performed retrospective review of medical notes, laboratory results, muscle imaging and histological findings of four patients with LGMD 2 l who were previously misdiagnosed with IIM. We focused on clinical presentation and progression, therapeutic agents used, and events leading to revision of the diagnosis. RESULTS Three males and one female patients with a mean age of 51 years at presentation were reviewed. In each case treatment with immunosuppressants, in one case for >15 years, was observed without a clear therapeutic response. All patients were negative for anti-nuclear antibodies and available myositis-associated/specific autoantibodies and associated connective tissue disease features were absent. Prominent fatty infiltration and selective muscle involvement on thigh muscle magnetic resonance imaging was a common. CONCLUSIONS Adult-onset genetic myopathies, particularly LGMD R12, can mimic IIM. Accurate diagnosis is crucial to avoid use of potentially harmful immunosuppressive therapies, allow appropriate genetic counselling, and facilitate involvement in research studies.
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Affiliation(s)
- Italo Marago
- Manchester Centre for Clinical Neuroscience, Salford Royal NHS Foundation Trust, Salford, UK
| | - Mark Roberts
- Manchester Centre for Clinical Neuroscience, Salford Royal NHS Foundation Trust, Salford, UK
| | - Federico Roncaroli
- Geoffrey Jefferson Brain Research Centre, Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Daniel DuPlessis
- Department of Cellular Pathology, Northern Care Alliance, Salford Royal NHS Foundation Trust, Salford, UK
| | - Caroline Sewry
- Department of Cellular Pathology, Northern Care Alliance, Salford Royal NHS Foundation Trust, Salford, UK
| | - Santhosh Nagaraju
- Department of Cellular Pathology, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Faheema Limbada
- Department of Cellular Pathology, Northern Care Alliance, Salford Royal NHS Foundation Trust, Salford, UK
| | - Chiara Marini-Bettolo
- The John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle, UK
| | - Judith Hudson
- The John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle, UK
| | - Siwalik Banerjee
- Department of Rheumatology, University Hospitals Coventry & Warwickshire NHS Trust, Coventry, UK
| | - Laura Newton
- Department of Rheumatology, Burnley General Teaching Hospital, East Lancashire Hospitals NHS Trust, Burnley, UK
| | - Marwan Bukhari
- Department of Rheumatology, University Hospitals of Morecambe Bay NHS Foundation Trust, Lancaster, UK
| | - Hector Chinoy
- Centre for Musculoskeletal Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,National Institute for Health Research Manchester Biomedical Research Centre, Manchester University NHS Foundation Trust, The University of Manchester, Manchester, UK.,Department of Rheumatology, Salford Royal NHS Foundation Trust, Manchester Academic Health Science Centre, Salford, UK
| | - James B Lilleker
- Manchester Centre for Clinical Neuroscience, Salford Royal NHS Foundation Trust, Salford, UK.,National Institute for Health Research Manchester Biomedical Research Centre, Manchester University NHS Foundation Trust, The University of Manchester, Manchester, UK
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Braga L, Ali H, Secco I, Chiavacci E, Neves G, Goldhill D, Penn R, Jimenez-Guardeño JM, Ortega-Prieto AM, Bussani R, Cannatà A, Rizzari G, Collesi C, Schneider E, Arosio D, Shah AM, Barclay WS, Malim MH, Burrone J, Giacca M. Drugs that inhibit TMEM16 proteins block SARS-CoV-2 spike-induced syncytia. Nature 2021; 594:88-93. [PMID: 33827113 PMCID: PMC7611055 DOI: 10.1038/s41586-021-03491-6] [Citation(s) in RCA: 253] [Impact Index Per Article: 84.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 03/25/2021] [Indexed: 02/01/2023]
Abstract
COVID-19 is a disease with unique characteristics that include lung thrombosis1, frequent diarrhoea2, abnormal activation of the inflammatory response3 and rapid deterioration of lung function consistent with alveolar oedema4. The pathological substrate for these findings remains unknown. Here we show that the lungs of patients with COVID-19 contain infected pneumocytes with abnormal morphology and frequent multinucleation. The generation of these syncytia results from activation of the SARS-CoV-2 spike protein at the cell plasma membrane level. On the basis of these observations, we performed two high-content microscopy-based screenings with more than 3,000 approved drugs to search for inhibitors of spike-driven syncytia. We converged on the identification of 83 drugs that inhibited spike-mediated cell fusion, several of which belonged to defined pharmacological classes. We focused our attention on effective drugs that also protected against virus replication and associated cytopathicity. One of the most effective molecules was the antihelminthic drug niclosamide, which markedly blunted calcium oscillations and membrane conductance in spike-expressing cells by suppressing the activity of TMEM16F (also known as anoctamin 6), a calcium-activated ion channel and scramblase that is responsible for exposure of phosphatidylserine on the cell surface. These findings suggest a potential mechanism for COVID-19 disease pathogenesis and support the repurposing of niclosamide for therapy.
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Affiliation(s)
- Luca Braga
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Hashim Ali
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Ilaria Secco
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Elena Chiavacci
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Guilherme Neves
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Daniel Goldhill
- Department of Infectious Diseases, Imperial College London, London, UK
| | - Rebecca Penn
- Department of Infectious Diseases, Imperial College London, London, UK
| | - Jose M Jimenez-Guardeño
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King's College London, London, UK
| | - Ana M Ortega-Prieto
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King's College London, London, UK
| | - Rossana Bussani
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Antonio Cannatà
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Giorgia Rizzari
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Chiara Collesi
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Edoardo Schneider
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Daniele Arosio
- Istituto di Biofisica (IBF), Consiglio Nazionale delle Ricerche (CNR), Trento, Italy
| | - Ajay M Shah
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Wendy S Barclay
- Department of Infectious Diseases, Imperial College London, London, UK
| | - Michael H Malim
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King's College London, London, UK
| | - Juan Burrone
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Mauro Giacca
- King's College London, British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, London, UK.
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.
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35
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Affiliation(s)
- Jarred M Whitlock
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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36
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The Groovy TMEM16 Family: Molecular Mechanisms of Lipid Scrambling and Ion Conduction. J Mol Biol 2021; 433:166941. [PMID: 33741412 DOI: 10.1016/j.jmb.2021.166941] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/09/2021] [Accepted: 03/09/2021] [Indexed: 12/28/2022]
Abstract
The TMEM16 family of membrane proteins displays a remarkable functional dichotomy - while some family members function as Ca2+-activated anion channels, the majority of characterized TMEM16 homologs are Ca2+-activated lipid scramblases, which catalyze the exchange of phospholipids between the two membrane leaflets. Furthermore, some TMEM16 scramblases can also function as channels. Due to their involvement in important physiological processes, the family has been actively studied ever since their molecular identity was unraveled. In this review, we will summarize the recent advances in the field and how they influenced our view of TMEM16 family function and evolution. Structural, functional and computational studies reveal how relatively small rearrangements in the permeation pathway are responsible for the observed functional duality: while TMEM16 scramblases can adopt both ion- and lipid conductive conformations, TMEM16 channels can only populate the former. Recent data further provides the molecular details of a stepwise activation mechanism, which is initiated by Ca2+ binding and modulated by various cellular factors, including lipids. TMEM16 function and the surrounding membrane properties are inextricably intertwined, with the protein inducing bilayer deformations associated with scrambling, while the surrounding lipids modulate TMEM16 conformation and activity.
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Foltz SJ, Cui YY, Choo HJ, Hartzell HC. ANO5 ensures trafficking of annexins in wounded myofibers. J Cell Biol 2021; 220:e202007059. [PMID: 33496727 PMCID: PMC7844426 DOI: 10.1083/jcb.202007059] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/20/2020] [Accepted: 12/23/2020] [Indexed: 12/14/2022] Open
Abstract
Mutations in ANO5 (TMEM16E) cause limb-girdle muscular dystrophy R12. Defective plasma membrane repair is a likely mechanism. Using myofibers from Ano5 knockout mice, we show that trafficking of several annexin proteins, which together form a cap at the site of injury, is altered upon loss of ANO5. Annexin A2 accumulates at the wound to nearly twice the level observed in WT fibers, while annexin A6 accumulation is substantially inhibited in the absence of ANO5. Appearance of annexins A1 and A5 at the cap is likewise diminished in the Ano5 knockout. These changes are correlated with an alteration in annexin repair cap fine structure and shedding of annexin-positive vesicles. We conclude that loss of annexin coordination during repair is disrupted in Ano5 knockout mice and underlies the defective repair phenotype. Although ANO5 is a phospholipid scramblase, abnormal repair is rescued by overexpression of a scramblase-defective ANO5 mutant, suggesting a novel, scramblase-independent role of ANO5 in repair.
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Affiliation(s)
| | | | - Hyojung J. Choo
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
| | - H. Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
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Flagging fusion: Phosphatidylserine signaling in cell-cell fusion. J Biol Chem 2021; 296:100411. [PMID: 33581114 PMCID: PMC8005811 DOI: 10.1016/j.jbc.2021.100411] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 02/06/2023] Open
Abstract
Formations of myofibers, osteoclasts, syncytiotrophoblasts, and fertilized zygotes share a common step, cell–cell fusion. Recent years have brought about considerable progress in identifying some of the proteins involved in these and other cell-fusion processes. However, even for the best-characterized cell fusions, we still do not know the mechanisms that regulate the timing of cell-fusion events. Are they fully controlled by the expression of fusogenic proteins or do they also depend on some triggering signal that activates these proteins? The latter scenario would be analogous to the mechanisms that control the timing of exocytosis initiated by Ca2+ influx and virus-cell fusion initiated by low pH- or receptor interaction. Diverse cell fusions are accompanied by the nonapoptotic exposure of phosphatidylserine at the surface of fusing cells. Here we review data on the dependence of membrane remodeling in cell fusion on phosphatidylserine and phosphatidylserine-recognizing proteins and discuss the hypothesis that cell surface phosphatidylserine serves as a conserved “fuse me” signal regulating the time and place of cell-fusion processes.
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Liang P, Yang H. Molecular underpinning of intracellular pH regulation on TMEM16F. J Gen Physiol 2021; 153:e202012704. [PMID: 33346788 PMCID: PMC7754671 DOI: 10.1085/jgp.202012704] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/29/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
TMEM16F, a dual-function phospholipid scramblase and ion channel, is important in blood coagulation, skeleton development, HIV infection, and cell fusion. Despite advances in understanding its structure and activation mechanism, how TMEM16F is regulated by intracellular factors remains largely elusive. Here we report that TMEM16F lipid scrambling and ion channel activities are strongly influenced by intracellular pH (pHi). We found that low pHi attenuates, whereas high pHi potentiates, TMEM16F channel and scramblase activation under physiological concentrations of intracellular Ca2+ ([Ca2+]i). We further demonstrate that TMEM16F pHi sensitivity depends on [Ca2+]i and exhibits a bell-shaped relationship with [Ca2+]i: TMEM16F channel activation becomes increasingly pHi sensitive from resting [Ca2+]i to micromolar [Ca2+]i, but when [Ca2+]i increases beyond 15 µM, pHi sensitivity gradually diminishes. The mutation of a Ca2+-binding residue that markedly reduces TMEM16F Ca2+ sensitivity (E667Q) maintains the bell-shaped relationship between pHi sensitivity and Ca2+ but causes a dramatic shift of the peak [Ca2+]i from 15 µM to 3 mM. Our biophysical characterizations thus pinpoint that the pHi regulatory effects on TMEM16F stem from the competition between Ca2+ and protons for the primary Ca2+-binding residues in the pore. Within the physiological [Ca2+]i range, the protonation state of the primary Ca2+-binding sites influences Ca2+ binding and regulates TMEM16F activation. Our findings thus uncover a regulatory mechanism of TMEM16F by pHi and shine light on our understanding of the pathophysiological roles of TMEM16F in diseases with dysregulated pHi, including cancer.
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Affiliation(s)
- Pengfei Liang
- Department of Biochemistry, Duke University Medical Center, Durham, NC
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC
- Department of Neurobiology, Duke University Medical Center, Durham, NC
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Le SC, Yang H. Structure-Function of TMEM16 Ion Channels and Lipid Scramblases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:87-109. [PMID: 35138612 PMCID: PMC11020148 DOI: 10.1007/978-981-16-4254-8_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The TMEM16 protein family comprises two novel classes of structurally conserved but functionally distinct membrane transporters that function as Ca2+-dependent Cl- channels (CaCCs) or dual functional Ca2+-dependent ion channels and phospholipid scramblases. Extensive functional and structural studies have advanced our understanding of TMEM16 molecular mechanisms and physiological functions. TMEM16A and TMEM16B CaCCs control transepithelial fluid transport, smooth muscle contraction, and neuronal excitability, whereas TMEM16 phospholipid scramblases mediate the flip-flop of phospholipids across the membrane to allow phosphatidylserine externalization, which is essential in a plethora of important processes such as blood coagulation, bone development, and viral and cell fusion. In this chapter, we summarize the major methods in studying TMEM16 ion channels and scramblases and then focus on the current mechanistic understanding of TMEM16 Ca2+- and voltage-dependent channel gating as well as their ion and phospholipid permeation.
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Affiliation(s)
- Son C Le
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
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Savarese M, Sarparanta J, Vihola A, Jonson PH, Johari M, Rusanen S, Hackman P, Udd B. Panorama of the distal myopathies. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2020; 39:245-265. [PMID: 33458580 PMCID: PMC7783427 DOI: 10.36185/2532-1900-028] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 11/11/2020] [Indexed: 12/15/2022]
Abstract
Distal myopathies are genetic primary muscle disorders with a prominent weakness at onset in hands and/or feet. The age of onset (from early childhood to adulthood), the distribution of muscle weakness (upper versus lower limbs) and the histological findings (ranging from nonspecific myopathic changes to myofibrillar disarrays and rimmed vacuoles) are extremely variable. However, despite being characterized by a wide clinical and genetic heterogeneity, the distal myopathies are a category of muscular dystrophies: genetic diseases with progressive loss of muscle fibers. Myopathic congenital arthrogryposis is also a form of distal myopathy usually caused by focal amyoplasia. Massive parallel sequencing has further expanded the long list of genes associated with a distal myopathy, and contributed identifying as distal myopathy-causative rare variants in genes more often related with other skeletal or cardiac muscle diseases. Currently, almost 20 genes (ACTN2, CAV3, CRYAB, DNAJB6, DNM2, FLNC, HNRNPA1, HSPB8, KHLH9, LDB3, MATR3, MB, MYOT, PLIN4, TIA1, VCP, NOTCH2NLC, LRP12, GIPS1) have been associated with an autosomal dominant form of distal myopathy. Pathogenic changes in four genes (ADSSL, ANO5, DYSF, GNE) cause an autosomal recessive form; and disease-causing variants in five genes (DES, MYH7, NEB, RYR1 and TTN) result either in a dominant or in a recessive distal myopathy. Finally, a digenic mechanism, underlying a Welander-like form of distal myopathy, has been recently elucidated. Rare pathogenic mutations in SQSTM1, previously identified with a bone disease (Paget disease), unexpectedly cause a distal myopathy when combined with a common polymorphism in TIA1. The present review aims at describing the genetic basis of distal myopathy and at summarizing the clinical features of the different forms described so far.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Jaakko Sarparanta
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Anna Vihola
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Neuromuscular Research Center, Department of Genetics, Fimlab Laboratories, Tampere, Finland
| | - Per Harald Jonson
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Mridul Johari
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Salla Rusanen
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Peter Hackman
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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Le T, Le SC, Zhang Y, Liang P, Yang H. Evidence that polyphenols do not inhibit the phospholipid scramblase TMEM16F. J Biol Chem 2020; 295:12537-12544. [PMID: 32709749 DOI: 10.1074/jbc.ac120.014872] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/23/2020] [Indexed: 01/06/2023] Open
Abstract
TMEM16 Ca2+-activated phospholipid scramblases (CaPLSases) mediate rapid transmembrane phospholipid flip-flop and as such play essential roles in various physiological and pathological processes such as blood coagulation, skeletal development, viral infection, cell-cell fusion, and ataxia. Pharmacological tools specifically targeting TMEM16 CaPLSases are urgently needed to understand these novel membrane transporters and their contributions to health and disease. Tannic acid (TA) and epigallocatechin gallate (EGCG) were recently reported as promising TMEM16F CaPLSase inhibitors. However, our present study shows that TA and EGCG do not inhibit the phospholipid-scrambling or ion conduction activities of the dual-functional TMEM16F. Instead, we found that TA and EGCG mainly acted as fluorescence quenchers that rapidly suppress the fluorophores conjugated to annexin V, a phosphatidylserine-binding probe commonly used to report on TMEM16 CaPLSase activity. These data demonstrate the false positive effects of TA and EGCG on inhibiting TMEM16F phospholipid scrambling and discourage the use of these polyphenols as CaPLSase inhibitors. Appropriate controls as well as a combination of both fluorescence imaging and electrophysiological validation are necessary in future endeavors to develop TMEM16 CaPLSase inhibitors.
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Affiliation(s)
- Trieu Le
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - Son C Le
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - Yang Zhang
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - Pengfei Liang
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA .,Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
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Yanay N, Rabie M, Nevo Y. Impaired Regeneration in Dystrophic Muscle-New Target for Therapy. Front Mol Neurosci 2020; 13:69. [PMID: 32523512 PMCID: PMC7261890 DOI: 10.3389/fnmol.2020.00069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 04/08/2020] [Indexed: 12/13/2022] Open
Abstract
Muscle stem cells (MuSCs), known as satellite cells (SCs) have an incredible ability to regenerate, which enables the maintenance and growth of muscle tissue. In response to damaging stimuli, SCs are activated, proliferate, differentiate, and fuse to repair or generate a new muscle fiber. However, dystrophic muscles are characterized by poor muscle regeneration along with chronic inflammation and fibrosis. Indications for SC involvement in muscular dystrophy pathologies are accumulating, but their contribution to muscle pathophysiology is not precisely understood. In congenital muscular dystrophy type 1A (LAMA2-CMD), mutations in Lama2 gene cause either complete or partial absence in laminin-211 protein. Laminin-211 functions as a link between muscle extracellular matrix (ECM) and two adhesion systems in the sarcolemma; one is the well-known dystrophin-glycoprotein complex (DGC), and the second is the integrin complex. Because of its protein interactions and location, laminin-211 has a crucial role in muscle function and survival by maintaining sarcolemma integrity. In addition, laminin-211 is expressed in SCs and suggested to have a role in SC proliferation and differentiation. Downstream to the primary defect in laminin-211, several secondary genes and pathways accelerate disease mechanism, while at the same time there are unsuccessful attempts to regenerate as compensation for the dystrophic process. Lately, next-generation sequencing platforms have advanced our knowledge about the secondary events occurring in various diseases, elucidate the pathophysiology, and characterize new essential targets for development of new treatment strategies. This review will mainly focus on SC contribution to impaired regeneration in muscular dystrophies and specifically new findings suggesting SC involvement in LAMA2-CMD pathology.
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Affiliation(s)
- Nurit Yanay
- Felsenstein Medical Research Center (FMRC), Tel-Aviv University, Tel-Aviv, Israel.,Institute of Neurology, Schneider Children's Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Malcolm Rabie
- Felsenstein Medical Research Center (FMRC), Tel-Aviv University, Tel-Aviv, Israel.,Institute of Neurology, Schneider Children's Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Yoram Nevo
- Felsenstein Medical Research Center (FMRC), Tel-Aviv University, Tel-Aviv, Israel.,Institute of Neurology, Schneider Children's Medical Center, Tel-Aviv University, Tel-Aviv, Israel
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44
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Di Zanni E, Gradogna A, Picco C, Scholz-Starke J, Boccaccio A. TMEM16E/ANO5 mutations related to bone dysplasia or muscular dystrophy cause opposite effects on lipid scrambling. Hum Mutat 2020; 41:1157-1170. [PMID: 32112655 DOI: 10.1002/humu.24006] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 02/21/2020] [Accepted: 02/25/2020] [Indexed: 12/14/2022]
Abstract
Mutations in the human TMEM16E/ANO5 gene are causative for gnathodiaphyseal dysplasia (GDD), a rare bone malformation and fragility disorder, and for two types of muscular dystrophy (MD). Previous studies have demonstrated that TMEM16E/ANO5 is a Ca2+ -activated phospholipid scramblase and that the mutation c.1538C>T (p.Thr513Ile) causing GDD leads to a gain-of-function phenotype. Here, using established HEK293-based functional assays, we investigated the effects of MD-related and further GDD-related amino acid exchanges on TMEM16E/ANO5 function in the same expression system. These experiments also revealed that the gradual changes in HEK293 cell morphology observed upon expression of TMEM16E/ANO5GDD mutants are a consequence of aberrant protein activity. Our results collectively demonstrate that, on the level of protein function, MD mutations are associated to loss-of-function and GDD mutations to gain-of-function phenotypes, confirming conjectures made on the basis of inheritance modes.
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Affiliation(s)
- Eleonora Di Zanni
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Antonella Gradogna
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Cristiana Picco
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | | | - Anna Boccaccio
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
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Phuong TTT, An J, Park SH, Kim A, Choi HB, Kang TM. Deficiency of Anoctamin 5/TMEM16E causes nuclear positioning defect and impairs Ca 2+ signaling of differentiated C2C12 myotubes. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:539-547. [PMID: 31680776 PMCID: PMC6819897 DOI: 10.4196/kjpp.2019.23.6.539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 09/30/2019] [Accepted: 09/30/2019] [Indexed: 12/05/2022]
Abstract
Anoctamin 5 (ANO5)/TMEM16E belongs to a member of the ANO/TMEM16 family member of anion channels. However, it is a matter of debate whether ANO5 functions as a genuine plasma membrane chloride channel. It has been recognized that mutations in the ANO5 gene cause many skeletal muscle diseases such as limb girdle muscular dystrophy type 2L (LGMD2L) and Miyoshi muscular dystrophy type 3 (MMD3) in human. However, the molecular mechanisms of the skeletal myopathies caused by ANO5 defects are poorly understood. To understand the role of ANO5 in skeletal muscle development and function, we silenced the ANO5 gene in C2C12 myoblasts and evaluated whether it impairs myogenesis and myotube function. ANO5 knockdown (ANO5-KD) by shRNA resulted in clustered or aggregated nuclei at the body of myotubes without affecting differentiation or myotube formation. Nuclear positioning defect of ANO5-KD myotubes was accompanied with reduced expression of Kif5b protein, a kinesin-related motor protein that controls nuclear transport during myogenesis. ANO5-KD impaired depolarization-induced [Ca2+]i transient and reduced sarcoplasmic reticulum (SR) Ca2+ storage. ANO5-KD resulted in reduced protein expression of the dihydropyridine receptor (DHPR) and SR Ca2+-ATPase subtype 1. In addition, ANO5-KD compromised co-localization between DHPR and ryanodine receptor subtype 1. It is concluded that ANO5-KD causes nuclear positioning defect by reduction of Kif5b expression, and compromises Ca2+ signaling by downregulating the expression of DHPR and SERCA proteins.
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Affiliation(s)
- Tam Thi Thanh Phuong
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Jieun An
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Sun Hwa Park
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Ami Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Hyun Bin Choi
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Tong Mook Kang
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
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Affiliation(s)
- Anna Boccaccio
- a Institute of Biophysics , Consiglio Nazionale delle Ricerche (CNR) , Genova , Italy
| | - Eleonora Di Zanni
- a Institute of Biophysics , Consiglio Nazionale delle Ricerche (CNR) , Genova , Italy
| | - Antonella Gradogna
- a Institute of Biophysics , Consiglio Nazionale delle Ricerche (CNR) , Genova , Italy
| | - Joachim Scholz-Starke
- a Institute of Biophysics , Consiglio Nazionale delle Ricerche (CNR) , Genova , Italy
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Stabilin Receptors: Role as Phosphatidylserine Receptors. Biomolecules 2019; 9:biom9080387. [PMID: 31434355 PMCID: PMC6723754 DOI: 10.3390/biom9080387] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 08/16/2019] [Accepted: 08/18/2019] [Indexed: 12/18/2022] Open
Abstract
Phosphatidylserine is a membrane phospholipid that is localized to the inner leaflet of the plasma membrane. Phosphatidylserine externalization to the outer leaflet of the plasma membrane is an important signal for various physiological processes, including apoptosis, platelet activation, cell fusion, lymphocyte activation, and regenerative axonal fusion. Stabilin-1 and stabilin-2 are membrane receptors that recognize phosphatidylserine on the cell surface. Here, we discuss the functions of Stabilin-1 and stabilin-2 as phosphatidylserine receptors in apoptotic cell clearance (efferocytosis) and cell fusion, and their ligand-recognition and signaling pathways.
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48
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Ye W, Han TW, He M, Jan YN, Jan LY. Dynamic change of electrostatic field in TMEM16F permeation pathway shifts its ion selectivity. eLife 2019; 8:e45187. [PMID: 31318330 PMCID: PMC6690719 DOI: 10.7554/elife.45187] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 07/17/2019] [Indexed: 12/11/2022] Open
Abstract
TMEM16F is activated by elevated intracellular Ca2+, and functions as a small-conductance ion channel and as a phospholipid scramblase. In contrast to its paralogs, the TMEM16A/B calcium-activated chloride channels, mouse TMEM16F has been reported as a cation-, anion-, or non-selective ion channel, without a definite conclusion. Starting with the Q559K mutant that shows no current rundown and less outward rectification in excised patch, we found that the channel shifted its ion selectivity in response to the change of intracellular Ca2+ concentration, with an increased permeability ratio of Cl- to Na+ (PCl-/PNa+) at a higher Ca2+ level. The gradual shift of relative ion permeability did not correlate with the channel activation state. Instead, it was indicative of an alteration of electrostatic field in the permeation pathway. The dynamic change of ion selectivity suggests a charge-screening mechanism for TMEM16F ion conduction, and it provides hints to further studies of TMEM16F physiological functions.
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Affiliation(s)
- Wenlei Ye
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Tina W Han
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Mu He
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Yuh Nung Jan
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
- Department of Biochemistry and BiophysicsUniversity of California, San FranciscoSan FranciscoUnited States
| | - Lily Yeh Jan
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
- Department of Biochemistry and BiophysicsUniversity of California, San FranciscoSan FranciscoUnited States
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Chandra G, Defour A, Mamchoui K, Pandey K, Mishra S, Mouly V, Sreetama S, Mahad Ahmad M, Mahjneh I, Morizono H, Pattabiraman N, Menon AK, Jaiswal JK. Dysregulated calcium homeostasis prevents plasma membrane repair in Anoctamin 5/TMEM16E-deficient patient muscle cells. Cell Death Discov 2019; 5:118. [PMID: 31341644 PMCID: PMC6639303 DOI: 10.1038/s41420-019-0197-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 06/10/2019] [Accepted: 06/13/2019] [Indexed: 01/30/2023] Open
Abstract
Autosomal recessive mutations in Anoctamin 5 (ANO5/TMEM16E), a member of the transmembrane 16 (TMEM16) family of Ca2+-activated ion channels and phospholipid scramblases, cause adult-onset muscular dystrophies (limb girdle muscular dystrophy 2L (LGMD2L) and Miyoshi Muscular Dystrophy (MMD3). However, the molecular role of ANO5 is unclear and ANO5 knockout mouse models show conflicting requirements of ANO5 in muscle. To study the role of ANO5 in human muscle cells we generated a myoblast line from a MMD3-patient carrying the c.2272C>T mutation, which we find causes the mutant protein to be degraded. The patient myoblasts exhibit normal myogenesis, but are compromised in their plasma membrane repair (PMR) ability. The repair deficit is linked to the poor ability of the endoplasmic reticulum (ER) to clear cytosolic Ca2+ increase caused by focal plasma membrane injury. Expression of wild-type ANO5 or pharmacological prevention of injury-triggered cytosolic Ca2+ overload enable injured patient muscle cells to repair. A homology model of ANO5 shows that several of the known LGMD2L/MMD3 patient mutations line the transmembrane region of the protein implicated in its channel activity. These results point to a role of cytosolic Ca2+ homeostasis in PMR, indicate a role for ANO5 in ER-mediated cytosolic Ca2+ uptake and identify normalization of cytosolic Ca2+ homeostasis as a potential therapeutic approach to treat muscular dystrophies caused by ANO5 deficit.
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Affiliation(s)
- Goutam Chandra
- 1Center of Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010 USA
| | - Aurelia Defour
- 1Center of Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010 USA.,7Present Address: Aix Marseille Université, UMR_S 910, Génétique Médicale et Génomique Fonctionnelle, 13385 Marseille, France
| | - Kamel Mamchoui
- 2Center for Research in Myology, Sorbonne Universités, UPMC Université Paris 06, INSERM UMRS974, 47 Boulevard de l'hôpital, 75013 Paris, France
| | - Kalpana Pandey
- 3Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065 USA
| | - Soumya Mishra
- 1Center of Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010 USA
| | - Vincent Mouly
- 2Center for Research in Myology, Sorbonne Universités, UPMC Université Paris 06, INSERM UMRS974, 47 Boulevard de l'hôpital, 75013 Paris, France
| | - SenChandra Sreetama
- 1Center of Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010 USA
| | - Mohammad Mahad Ahmad
- 1Center of Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010 USA
| | - Ibrahim Mahjneh
- 4Department of Neurology, MRC Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Hiroki Morizono
- 1Center of Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010 USA.,5Department of Genomics and Precision Medicine, George Washington University, Washington, DC 20037 USA
| | | | - Anant K Menon
- 3Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065 USA
| | - Jyoti K Jaiswal
- 1Center of Genetic Medicine Research, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010 USA.,5Department of Genomics and Precision Medicine, George Washington University, Washington, DC 20037 USA
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Le T, Jia Z, Le SC, Zhang Y, Chen J, Yang H. An inner activation gate controls TMEM16F phospholipid scrambling. Nat Commun 2019; 10:1846. [PMID: 31015464 PMCID: PMC6478717 DOI: 10.1038/s41467-019-09778-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/27/2019] [Indexed: 12/15/2022] Open
Abstract
Transmembrane protein 16F (TMEM16F) is an enigmatic Ca2+-activated phospholipid scramblase (CaPLSase) that passively transports phospholipids down their chemical gradients and mediates blood coagulation, bone development and viral infection. Despite recent advances in the structure and function understanding of TMEM16 proteins, how mammalian TMEM16 CaPLSases open and close, or gate their phospholipid permeation pathways remains unclear. Here we identify an inner activation gate, which is established by three hydrophobic residues, F518, Y563 and I612, in the middle of the phospholipid permeation pathway of TMEM16F-CaPLSase. Disrupting the inner gate profoundly alters TMEM16F phospholipid permeation. Lysine substitutions of F518 and Y563 even lead to constitutively active CaPLSases that bypass Ca2+-dependent activation. Strikingly, an analogous lysine mutation to TMEM16F-F518 in TMEM16A (L543K) is sufficient to confer CaPLSase activity to the Ca2+-activated Cl- channel (CaCC). The identification of an inner activation gate can help elucidate the gating and permeation mechanism of TMEM16 CaPLSases and channels.
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Affiliation(s)
- Trieu Le
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Zhiguang Jia
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
| | - Son C Le
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Yang Zhang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, 01003, MA, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA.
- Department of Neurobiology, Duke University Medical Center, Durham, 27710, NC, USA.
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