1
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Moran O, Tammaro P. Identification of determinants of lipid and ion transport in TMEM16/anoctamin proteins through a Bayesian statistical analysis. Biophys Chem 2024; 308:107194. [PMID: 38401241 DOI: 10.1016/j.bpc.2024.107194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 01/17/2024] [Accepted: 01/28/2024] [Indexed: 02/26/2024]
Abstract
The TMEM16/Anoctamin protein family (TMEM16x) is composed of members with different functions; some members form Ca2+-activated chloride channels, while others are lipid scramblases or combine the two functions. TMEM16x proteins are typically activated in response to agonist-induced rises of intracellular Ca2+; thus, they couple Ca2+-signalling with cell electrical activity or plasmalemmal lipid homeostasis. The structural domains underlying these functions are not fully defined. We used a Naïve Bayes classifier to gain insights into these domains. The method enabled identification of regions involved in either ion or lipid transport, and suggested domains for possible pharmacological exploitation. The method allowed the prediction of the transport property of any given TMEM16x. We envisage this strategy could be exploited to illuminate the structure-function relationship of any protein family composed of members playing different molecular roles.
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Affiliation(s)
- Oscar Moran
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche (CNR), Via De Marini 6, 16149 Genova, Italy
| | - Paolo Tammaro
- Department Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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2
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Han Y, Zhou Z, Jin R, Dai F, Ge Y, Ju X, Ma X, He S, Yuan L, Wang Y, Yang W, Yue X, Chen Z, Sun Y, Corry B, Cox CD, Zhang Y. Mechanical activation opens a lipid-lined pore in OSCA ion channels. Nature 2024; 628:910-918. [PMID: 38570680 DOI: 10.1038/s41586-024-07256-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 02/28/2024] [Indexed: 04/05/2024]
Abstract
OSCA/TMEM63 channels are the largest known family of mechanosensitive channels1-3, playing critical roles in plant4-7 and mammalian8,9 mechanotransduction. Here we determined 44 cryogenic electron microscopy structures of OSCA/TMEM63 channels in different environments to investigate the molecular basis of OSCA/TMEM63 channel mechanosensitivity. In nanodiscs, we mimicked increased membrane tension and observed a dilated pore with membrane access in one of the OSCA1.2 subunits. In liposomes, we captured the fully open structure of OSCA1.2 in the inside-in orientation, in which the pore shows a large lateral opening to the membrane. Unusually for ion channels, structural, functional and computational evidence supports the existence of a 'proteo-lipidic pore' in which lipids act as a wall of the ion permeation pathway. In the less tension-sensitive homologue OSCA3.1, we identified an 'interlocking' lipid tightly bound in the central cleft, keeping the channel closed. Mutation of the lipid-coordinating residues induced OSCA3.1 activation, revealing a conserved open conformation of OSCA channels. Our structures provide a global picture of the OSCA channel gating cycle, uncover the importance of bound lipids and show that each subunit can open independently. This expands both our understanding of channel-mediated mechanotransduction and channel pore formation, with important mechanistic implications for the TMEM16 and TMC protein families.
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Affiliation(s)
- Yaoyao Han
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- Shanghai Key Laboratory of Aging Studies, Shanghai, China
| | - Zijing Zhou
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales, Sydney, New South Wales, Australia
| | - Ruitao Jin
- Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia
| | - Fei Dai
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- Shanghai Key Laboratory of Aging Studies, Shanghai, China
| | - Yifan Ge
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Xisan Ju
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- Shanghai Key Laboratory of Aging Studies, Shanghai, China
| | - Xiaonuo Ma
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- Shanghai Key Laboratory of Aging Studies, Shanghai, China
| | - Sitong He
- Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia
| | - Ling Yuan
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yingying Wang
- Department of Biophysics, and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Yang
- Department of Biophysics, and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaomin Yue
- Department of Biophysics, and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhongwen Chen
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Yadong Sun
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ben Corry
- Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia.
| | - Charles D Cox
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia.
- School of Biomedical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.
| | - Yixiao Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
- Shanghai Key Laboratory of Aging Studies, Shanghai, China.
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
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3
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Ousingsawat J, Centeio R, Schreiber R, Kunzelmann K. Niclosamide, but not ivermectin, inhibits anoctamin 1 and 6 and attenuates inflammation of the respiratory tract. Pflugers Arch 2024; 476:211-227. [PMID: 37979051 DOI: 10.1007/s00424-023-02878-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/19/2023]
Abstract
Inflammatory airway diseases like cystic fibrosis, asthma and COVID-19 are characterized by high levels of pulmonary cytokines. Two well-established antiparasitic drugs, niclosamide and ivermectin, are intensively discussed for the treatment of viral inflammatory airway infections. Here, we examined these repurposed drugs with respect to their anti-inflammatory effects in airways in vivo and in vitro. Niclosamide reduced mucus content, eosinophilic infiltration and cell death in asthmatic mouse lungs in vivo and inhibited release of interleukins in the two differentiated airway epithelial cell lines CFBE and BCi-NS1.1 in vitro. Cytokine release was also inhibited by the knockdown of the Ca2+-activated Cl- channel anoctamin 1 (ANO1, TMEM16A) and the phospholipid scramblase anoctamin 6 (ANO6, TMEM16F), which have previously been shown to affect intracellular Ca2+ levels near the plasma membrane and to facilitate exocytosis. At concentrations around 200 nM, niclosamide inhibited inflammation, lowered intracellular Ca2+, acidified cytosolic pH and blocked activation of ANO1 and ANO6. It is suggested that niclosamide brings about its anti-inflammatory effects at least in part by inhibiting ANO1 and ANO6, and by lowering intracellular Ca2+ levels. In contrast to niclosamide, 1 µM ivermectin did not exert any of the effects described for niclosamide. The present data suggest niclosamide as an effective anti-inflammatory treatment in CF, asthma, and COVID-19, in addition to its previously reported antiviral effects. It has an advantageous concentration-response relationship and is known to be well tolerated.
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Affiliation(s)
- Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, Germany University Street 31, 93053, Regensburg, Germany
| | - Raquel Centeio
- Physiological Institute, University of Regensburg, Germany University Street 31, 93053, Regensburg, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Germany University Street 31, 93053, Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Germany University Street 31, 93053, Regensburg, Germany.
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4
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Ye Z, Galvanetto N, Puppulin L, Pifferi S, Flechsig H, Arndt M, Triviño CAS, Di Palma M, Guo S, Vogel H, Menini A, Franz CM, Torre V, Marchesi A. Structural heterogeneity of the ion and lipid channel TMEM16F. Nat Commun 2024; 15:110. [PMID: 38167485 PMCID: PMC10761740 DOI: 10.1038/s41467-023-44377-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
Transmembrane protein 16 F (TMEM16F) is a Ca2+-activated homodimer which functions as an ion channel and a phospholipid scramblase. Despite the availability of several TMEM16F cryogenic electron microscopy (cryo-EM) structures, the mechanism of activation and substrate translocation remains controversial, possibly due to restrictions in the accessible protein conformational space. In this study, we use atomic force microscopy under physiological conditions to reveal a range of structurally and mechanically diverse TMEM16F assemblies, characterized by variable inter-subunit dimerization interfaces and protomer orientations, which have escaped prior cryo-EM studies. Furthermore, we find that Ca2+-induced activation is associated to stepwise changes in the pore region that affect the mechanical properties of transmembrane helices TM3, TM4 and TM6. Our direct observation of membrane remodelling in response to Ca2+ binding along with additional electrophysiological analysis, relate this structural multiplicity of TMEM16F to lipid and ion permeation processes. These results thus demonstrate how conformational heterogeneity of TMEM16F directly contributes to its diverse physiological functions.
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Affiliation(s)
- Zhongjie Ye
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China
| | - Nicola Galvanetto
- Department of Physics, University of Zurich, 8057, Zurich, Switzerland
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Leonardo Puppulin
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, I-30172 Mestre, Venice, Italy
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan
| | - Simone Pifferi
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, 60126, Ancona, Italy
| | - Holger Flechsig
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan
| | - Melanie Arndt
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | | | - Michael Di Palma
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, 60126, Ancona, Italy
| | - Shifeng Guo
- Shenzhen Key Laboratory of Smart Sensing and Intelligent Systems, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- Guangdong Provincial Key Lab of Robotics and Intelligent System, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Horst Vogel
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China
- Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Anna Menini
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy
| | - Clemens M Franz
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan
| | - Vincent Torre
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy.
- Institute of Materials (ION-CNR), Area Science Park, Basovizza, 34149, Trieste, Italy.
- BIoValley Investments System and Solutions (BISS), 34148, Trieste, Italy.
| | - Arin Marchesi
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan.
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, 60126, Ancona, Italy.
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5
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Ferreira-Santos L, Ramirez-Perez FI, Foote CA, Augenreich MA, McMillan NJ, Williams MB, Gonzalez-Vallejo JD, Power G, Wheeler AA, Manrique-Acevedo C, Martinez-Lemus LA, Padilla J. Neuraminidase-induced externalization of phosphatidylserine activates ADAM17 and impairs insulin signaling in endothelial cells. Am J Physiol Heart Circ Physiol 2024; 326:H270-H277. [PMID: 37999645 DOI: 10.1152/ajpheart.00638.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/08/2023] [Accepted: 11/08/2023] [Indexed: 11/25/2023]
Abstract
Endothelial insulin resistance represents a causal factor in the pathogenesis of type 2 diabetes (T2D) and vascular disease, thus the need to identify molecular mechanisms underlying defects in endothelial insulin signaling. We previously have shown that a disintegrin and metalloproteinase-17 (ADAM17) is increased while insulin receptor α-subunit (IRα) is decreased in the vasculature of patients with T2D, leading to impaired insulin-induced vasodilation. We have also demonstrated that ADAM17 sheddase activity targets IRα; however, the mechanisms driving endothelial ADAM17 activity in T2D are largely unknown. Herein, we report that externalization of phosphatidylserine (PS) to the outer leaflet of the plasma membrane causes ADAM17-mediated shedding of IRα and blunting of insulin signaling in endothelial cells. Furthermore, we demonstrate that endothelial PS externalization is mediated by the phospholipid scramblase anoctamin-6 (ANO6) and that this process can be stimulated by neuraminidase, a soluble enzyme that cleaves sialic acid residues. Of note, we demonstrate that men and women with T2D display increased levels of neuraminidase activity in plasma, relative to age-matched healthy individuals, and this occurs in conjunction with increased ADAM17 activity and impaired leg blood flow responses to endogenous insulin. Collectively, this work reveals the neuraminidase-ANO6-ADAM17 axis as a novel potential target for restoring endothelial insulin sensitivity in T2D.NEW & NOTEWORTHY This work provides the first evidence that neuraminidase, an enzyme increased in the circulation of men and women with type 2 diabetes (T2D), promotes anoctamin-6 (ANO6)-dependent externalization of phosphatidylserine in endothelial cells, which in turn leads to activation of a disintegrin and metalloproteinase-17 (ADAM17) and consequent shedding of the insulin receptor-α from the cell surface. Hence, this work supports that consideration should be given to the neuraminidase-ANO6-ADAM17 axis as a novel potential target for restoring endothelial insulin sensitivity in T2D.
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Affiliation(s)
| | | | - Christopher A Foote
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, United States
| | - Marc A Augenreich
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
| | - Neil J McMillan
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
| | - Morgan B Williams
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
| | | | - Gavin Power
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
| | - Andrew A Wheeler
- Department of Surgery, University of Missouri, Columbia, Missouri, United States
| | - Camila Manrique-Acevedo
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri, Columbia, Missouri, United States
- Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri, United States
| | - Luis A Martinez-Lemus
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, United States
- Center for Precision Medicine, Department of Medicine, University of Missouri, Columbia, Missouri, United States
| | - Jaume Padilla
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
- Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri, United States
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6
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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Feng S, Puchades C, Ko J, Wu H, Chen Y, Figueroa EE, Gu S, Han TW, Ho B, Cheng T, Li J, Shoichet B, Jan YN, Cheng Y, Jan LY. Identification of a drug binding pocket in TMEM16F calcium-activated ion channel and lipid scramblase. Nat Commun 2023; 14:4874. [PMID: 37573365 PMCID: PMC10423226 DOI: 10.1038/s41467-023-40410-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 07/23/2023] [Indexed: 08/14/2023] Open
Abstract
The dual functions of TMEM16F as Ca2+-activated ion channel and lipid scramblase raise intriguing questions regarding their molecular basis. Intrigued by the ability of the FDA-approved drug niclosamide to inhibit TMEM16F-dependent syncytia formation induced by SARS-CoV-2, we examined cryo-EM structures of TMEM16F with or without bound niclosamide or 1PBC, a known blocker of TMEM16A Ca2+-activated Cl- channel. Here, we report evidence for a lipid scrambling pathway along a groove harboring a lipid trail outside the ion permeation pore. This groove contains the binding pocket for niclosamide and 1PBC. Mutations of two residues in this groove specifically affect lipid scrambling. Whereas mutations of some residues in the binding pocket of niclosamide and 1PBC reduce their inhibition of TMEM16F-mediated Ca2+ influx and PS exposure, other mutations preferentially affect the ability of niclosamide and/or 1PBC to inhibit TMEM16F-mediated PS exposure, providing further support for separate pathways for ion permeation and lipid scrambling.
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Affiliation(s)
- Shengjie Feng
- Department of Physiology, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Cristina Puchades
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Juyeon Ko
- Department of Physiology, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Hao Wu
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Yifei Chen
- Howard Hughes Medical Institute; UCSF, San Francisco, CA, USA
| | - Eric E Figueroa
- Department of Physiology, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Shuo Gu
- BioDuro-Sundia Inc., Irvine, CA, USA
| | - Tina W Han
- Department of Physiology, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
- Dewpoint Therapeutics, Boston, MA, USA
| | - Brandon Ho
- Department of Physiology, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Tong Cheng
- Howard Hughes Medical Institute; UCSF, San Francisco, CA, USA
| | - Junrui Li
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Brian Shoichet
- Department of Pharmaceutical Chemistry, University of California San Francisco (UCSF) School of Pharmacy, San Francisco, CA, USA
| | - Yuh Nung Jan
- Department of Physiology, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
- Howard Hughes Medical Institute; UCSF, San Francisco, CA, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA.
- Howard Hughes Medical Institute; UCSF, San Francisco, CA, USA.
| | - Lily Yeh Jan
- Department of Physiology, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA.
- Howard Hughes Medical Institute; UCSF, San Francisco, CA, USA.
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8
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Kim H, Kim H, Nguyen LT, Ha T, Lim S, Kim K, Kim SH, Han K, Hyeon SJ, Ryu H, Park YS, Kim SH, Kim IB, Hong GS, Lee SE, Choi Y, Cohen LB, Oh U. Amplification of olfactory signals by Anoctamin 9 is important for mammalian olfaction. Prog Neurobiol 2022; 219:102369. [PMID: 36330924 DOI: 10.1016/j.pneurobio.2022.102369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
Sensing smells of foods, prey, or predators determines animal survival. Olfactory sensory neurons in the olfactory epithelium (OE) detect odorants, where cAMP and Ca2+ play a significant role in transducing odorant inputs to electrical activity. Here we show Anoctamin 9, a cation channel activated by cAMP/PKA pathway, is expressed in the OE and amplifies olfactory signals. Ano9-deficient mice had reduced olfactory behavioral sensitivity, electro-olfactogram signals, and neural activity in the olfactory bulb. In line with the difference in olfaction between birds and other vertebrates, chick ANO9 failed to respond to odorants, whereas chick CNGA2, a major transduction channel, showed greater responses to cAMP. Thus, we concluded that the signal amplification by ANO9 is important for mammalian olfactory transduction.
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Affiliation(s)
- Hyungsup Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyesu Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Luan Thien Nguyen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Taewoong Ha
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Sujin Lim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyungmin Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Soon Ho Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Kyungreem Han
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Seung Jae Hyeon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hoon Ryu
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Yong Soo Park
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Sang Hyun Kim
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - In-Beom Kim
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Gyu-Sang Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Seung Eun Lee
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Yunsook Choi
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Lawrence B Cohen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Uhtaek Oh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
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9
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Jia Z, Huang J, Chen J. Activation of TMEM16F by inner gate charged mutations and possible lipid/ion permeation mechanisms. Biophys J 2022; 121:3445-3457. [PMID: 35978550 PMCID: PMC9515230 DOI: 10.1016/j.bpj.2022.08.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/24/2022] [Accepted: 08/12/2022] [Indexed: 11/19/2022] Open
Abstract
Transmembrane protein 16F (TMEM16F) is a ubiquitously expressed Ca2+-activated phospholipid scramblase that also functions as a largely non-selective ion channel. Though recent structural studies have revealed the closed and intermediate conformations of mammalian TMEM16F (mTMEM16F), the open and conductive state remains elusive. Instead, it has been proposed that an open hydrophilic pathway may not be required for lipid scrambling. We previously identified an inner activation gate, consisting of F518, Y563, and I612, and showed that charged mutations of the inner gate residues led to constitutively active mTMEM16F scrambling. Herein, atomistic simulations show that lysine substitution of F518 and Y563 can indeed lead to spontaneous opening of the permeation pore in the Ca2+-bound state of mTMEM16F. Dilation of the pore exposes hydrophilic patches in the upper pore region, greatly increases the pore hydration level, and enables lipid scrambling. The putative open state of mTMEM16F resembles the active state of fungal scramblases and is a meta-stable state for the wild-type protein in the Ca2+-bound state. Therefore, mTMEM16F may be capable of supporting the canonical in-groove scrambling mechanism in addition to the out-of-groove one. Further analysis reveals that the in-groove phospholipid and ion transduction pathways of mTMEM16F overlap from the intracellular side up to the inner gate but diverge from each other with different exits to the extracellular side of membrane.
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Affiliation(s)
- Zhiguang Jia
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts
| | - Jian Huang
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts; Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts.
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10
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Fukami T, Shiozaki A, Kosuga T, Kudou M, Shimizu H, Ohashi T, Arita T, Konishi H, Komatsu S, Kubota T, Fujiwara H, Okamoto K, Kishimoto M, Morinaga Y, Konishi E, Otsuji E. Anoctamin 5 regulates the cell cycle and affects prognosis in gastric cancer. World J Gastroenterol 2022; 28:4649-4667. [PMID: 36157935 PMCID: PMC9476871 DOI: 10.3748/wjg.v28.i32.4649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/10/2022] [Accepted: 07/27/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Anoctamin 5 (ANO5)/transmembrane protein 16E belongs to the ANO/ transmembrane protein 16 anion channel family. ANOs comprise a family of plasma membrane proteins that mediate ion transport and phospholipid scrambling and regulate other membrane proteins in numerous cell types. Previous studies have elucidated the roles and mechanisms of ANO5 activation in various cancer types. However, it remains unclear whether ANO5 acts as a plasma membrane chloride channel, and its expression and functions in gastric cancer (GC) have not been investigated.
AIM To examine the role of ANO5 in the regulation of tumor progression and clinicopathological significance of its expression in GC.
METHODS Knockdown experiments using ANO5 small interfering RNA were conducted in human GC cell lines, and changes in cell proliferation, cell cycle progression, apoptosis, and cellular movement were assessed. The gene expression profiles of GC cells were investigated following ANO5 silencing by microarray analysis. Immunohistochemical staining of ANO5 was performed on 195 primary tumor samples obtained from patients with GC who underwent curative gastrectomy between 2011 and 2013 at our department.
RESULTS Reverse transcription-quantitative polymerase chain reaction (PCR) and western blotting demonstrated high ANO5 mRNA and protein expression, respectively, in NUGC4 and MKN45 cells. In these cells, ANO5 silencing inhibited cell proliferation and induced apoptosis. In addition, the knockdown of ANO5 inhibited G1-S phase progression, invasion, and migration. The results of the microarray analysis revealed changes in the expression levels of several cyclin-associated genes, such as CDKN1A, CDK2/4/6, CCNE2, and E2F1, in ANO5-depleted NUGC4 cells. The expression of these genes was verified using reverse transcription-quantitative PCR. Immunohistochemical staining revealed that high ANO5 expression levels were associated with a poor prognosis. Multivariate analysis identified high ANO5 expression as an independent prognostic factor for 5-year survival in patients with GC (P = 0.0457).
CONCLUSION ANO5 regulates the cell cycle progression by regulating the expression of cyclin-associated genes and affects the prognosis of patients with GC. These results may provide insights into the role of ANO5 as a key mediator in tumor progression and/or promising prognostic biomarker for GC.
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Affiliation(s)
- Tomoyuki Fukami
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Atsushi Shiozaki
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Toshiyuki Kosuga
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Michihiro Kudou
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Hiroki Shimizu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Takuma Ohashi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Tomohiro Arita
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Hirotaka Konishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Shuhei Komatsu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Takeshi Kubota
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Hitoshi Fujiwara
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Kazuma Okamoto
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Mitsuo Kishimoto
- Department of Pathology, Kyoto City Hospital, Kyoto 604-8845, Japan
| | - Yukiko Morinaga
- Department of Pathology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Eiichi Konishi
- Department of Pathology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Eigo Otsuji
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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11
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Zhang Y, Liang P, Yang L, Shan KZ, Feng L, Chen Y, Liedtke W, Coyne CB, Yang H. Functional coupling between TRPV4 channel and TMEM16F modulates human trophoblast fusion. eLife 2022; 11:e78840. [PMID: 35670667 PMCID: PMC9236608 DOI: 10.7554/elife.78840] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/05/2022] [Indexed: 11/15/2022] Open
Abstract
TMEM16F, a Ca2+-activated phospholipid scramblase (CaPLSase), is critical for placental trophoblast syncytialization, HIV infection, and SARS-CoV2-mediated syncytialization, however, how TMEM16F is activated during cell fusion is unclear. Here, using trophoblasts as a model for cell fusion, we demonstrate that Ca2+ influx through the Ca2+ permeable transient receptor potential vanilloid channel TRPV4 is critical for TMEM16F activation and plays a role in subsequent human trophoblast fusion. GSK1016790A, a TRPV4 specific agonist, robustly activates TMEM16F in trophoblasts. We also show that TRPV4 and TMEM16F are functionally coupled within Ca2+ microdomains in a human trophoblast cell line using patch-clamp electrophysiology. Pharmacological inhibition or gene silencing of TRPV4 hinders TMEM16F activation and subsequent trophoblast syncytialization. Our study uncovers the functional expression of TRPV4 and one of the physiological activation mechanisms of TMEM16F in human trophoblasts, thus providing us with novel strategies to regulate CaPLSase activity as a critical checkpoint of physiologically and disease-relevant cell fusion events.
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Affiliation(s)
- Yang Zhang
- Department of Biochemistry, Duke University Medical CenterDurhamUnited States
| | - Pengfei Liang
- Department of Biochemistry, Duke University Medical CenterDurhamUnited States
| | - Liheng Yang
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Ke Zoe Shan
- Department of Biochemistry, Duke University Medical CenterDurhamUnited States
| | - Liping Feng
- Department of Obstetrics and Gynecology, Duke University Medical CentreDurhamUnited States
- MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua HospitalShanghaiChina
| | - Yong Chen
- Department of Neurology, Duke University Medical CenterDurhamUnited States
| | - Wolfgang Liedtke
- Department of Neurology, Duke University Medical CenterDurhamUnited States
- Department of Anesthesiology, Duke University Medical CenterDurhamUnited States
- Department of Neurobiology, Duke University Medical CenterDurhamUnited States
- College of Dentistry, Department of Molecular Pathobiology, NYUNew YorkUnited States
| | - Carolyn B Coyne
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
- Duke Human Vaccine Institute, Duke UniversityDurhamUnited States
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical CenterDurhamUnited States
- Department of Neurobiology, Duke University Medical CenterDurhamUnited States
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12
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Yu H, Wang Z, Li Z, An Y, Yan M, Ji S, Xu M, Wang L, Dong W, Shi J, Gao C. Hyperuricemia enhances procoagulant activity of vascular endothelial cells through TMEM16F regulated phosphatidylserine exposure and microparticle release. FASEB J 2021; 35:e21808. [PMID: 34390515 DOI: 10.1096/fj.202100426r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/12/2021] [Accepted: 07/06/2021] [Indexed: 12/15/2022]
Abstract
The link between serum uric acid (SUA) and the risk of venous thromboembolism (VTE) is well established. Recent data suggested a causative role of UA in endothelial cells (ECs) dysfunction. However, the molecular mechanism of high UA on thrombogenesis is unknown. We investigate whether high UA induce phosphatidylserine (PS) externalization and microparticle (MP) shedding in cultured EC, and contribute to UA-induced hypercoagulable state. In the present study, we demonstrate that UA induces PS exposure and EMP release of EC in a concentration- and time-dependent manner, which enhances the procoagulant activity (PCA) of EC and inhibited over 90% by lactadherin in vitro. Furthermore, hyperuricemic rat model was used to evaluate the development of thrombi following by flow stasis in the inferior vena cava (IVC). Hyperuricemia group is more likely to form large and hard thrombi compared with control. Importantly, we found that TMEM16F expression is significantly upregulated in UA-treated EC, which is crucial for UA-induced PS exposure and MP formation. Additionally, UA increases the generation of reactive oxygen species (ROS), lipid peroxidation, and cytosolic Ca2+ concentration in EC, which might contribute to increased TMEM16F expression. Using confocal microscopy, we also observed disruption of the actin cytoskeleton, suggesting that depolymerization of actin filaments might be required for TMEM16F activation and followed by PS exposure and membrane blebbing in UA-treated EC. Our results demonstrate a thrombotic role of EC in hyperuricemia through TMEM16F-mediated PS exposure and MPs release.
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Affiliation(s)
- Hongyin Yu
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
| | - Zelong Wang
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
| | - Zhanni Li
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
| | - Yao An
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
| | - Meishan Yan
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
| | - Shuting Ji
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
| | - Minghui Xu
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
| | - Liqiu Wang
- Department of Clinical Laboratory, The Fifth Hospital, Harbin Medical University, Daqing, China
| | - Weijun Dong
- Department of General Surgery, The Fifth Hospital, Harbin Medical University, Daqing, China
| | - Jialan Shi
- Department of Hematology, The First Hospital, Harbin Medical University, Harbin, China
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Chunyan Gao
- Department of Medical Laboratory Science and Technology, Harbin Medical University-Daqing, Daqing, China
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13
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Abstract
Cells can expand their plasma membrane laterally by unfolding membrane undulations and by exocytosis. Here, we describe a third mechanism involving invaginations held shut by the membrane adapter, dynamin. Compartments open when Ca activates the lipid scramblase, TMEM16F, anionic phospholipids escape from the cytoplasmic monolayer in exchange for neutral lipids, and dynamins relax. Deletion of TMEM16F or dynamins blocks expansion, with loss of dynamin expression generating a maximally expanded basal plasma membrane state. Re-expression of dynamin2 or its GTPase-inactivated mutant, but not a lipid binding mutant, regenerates reserve compartments and rescues expansion. Dynamin2-GFP fusion proteins form punctae that rapidly dissipate from these compartments during TMEM16F activation. Newly exposed compartments extend deeply into the cytoplasm, lack numerous organellar markers, and remain closure-competent for many seconds. Without Ca, compartments open slowly when dynamins are sequestered by cytoplasmic dynamin antibodies or when scrambling is mimicked by neutralizing anionic phospholipids and supplementing neutral lipids. Activation of Ca-permeable mechanosensitive channels via cell swelling or channel agonists opens the compartments in parallel with phospholipid scrambling. Thus, dynamins and TMEM16F control large plasma membrane reserves that open in response to lateral membrane stress and Ca influx.
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Affiliation(s)
- Christine Deisl
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, TX, USA
| | - Donald W Hilgemann
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, TX, USA.
| | - Ruhma Syeda
- University of Texas Southwestern Medical Center, Department of Neuroscience, Dallas, TX, USA
| | - Michael Fine
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, TX, USA.
- University of Texas Southwestern Medical Center, Department of Molecular Genetics, Dallas, TX, USA.
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14
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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: 246] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Kolesnikov D, Perevoznikova A, Gusev K, Glushankova L, Kaznacheyeva E, Shalygin A. Electrophysiological Properties of Endogenous Single Ca 2+ Activated Cl - Channels Induced by Local Ca 2+ Entry in HEK293. Int J Mol Sci 2021; 22:4767. [PMID: 33946319 PMCID: PMC8124839 DOI: 10.3390/ijms22094767] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 12/19/2022] Open
Abstract
Microdomains formed by proteins of endoplasmic reticulum and plasma membrane play a key role in store-operated Ca2+ entry (SOCE). Ca2+ release through inositol 1,4,5-trisphosphate receptor (IP3R) and subsequent Ca2+ store depletion activate STIM (stromal interaction molecules) proteins, sensors of intraluminal Ca2+, which, in turn, open the Orai channels in plasma membrane. Downstream to this process could be activated TRPC (transient receptor potential-canonical) calcium permeable channels. Using single channel patch-clamp technique we found that a local Ca2+ entry through TRPC1 channels activated endogenous Ca2+-activated chloride channels (CaCCs) with properties similar to Anoctamin6 (TMEM16F). Our data suggest that their outward rectification is based on the dependence from membrane potential of both the channel conductance and the channel activity: (1) The conductance of active CaCCs highly depends on the transmembrane potential (from 3 pS at negative potentials till 60 pS at positive potentials); (2) their activity (NPo) is enhanced with increasing Ca2+ concentration and/or transmembrane potential, conversely lowering of intracellular Ca2+ concentration reduced the open state dwell time; (3) CaCC amplitude is only slightly increased by intracellular Ca2+ concentration. Experiments with Ca2+ buffering by EGTA or BAPTA suggest close local arrangement of functional CaCCs and TRPC1 channels. It is supposed that Ca2+-activated chloride channels are involved in Ca2+ entry microdomains.
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Affiliation(s)
| | | | | | | | - Elena Kaznacheyeva
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, 194064 St. Petersburg, Russia; (D.K.); (A.P.); (K.G.); (L.G.)
| | - Alexey Shalygin
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, 194064 St. Petersburg, Russia; (D.K.); (A.P.); (K.G.); (L.G.)
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16
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Connolly A, Panes R, Tual M, Lafortune R, Bellemare-Pelletier A, Gagnon E. TMEM16F mediates bystander TCR-CD3 membrane dissociation at the immunological synapse and potentiates T cell activation. Sci Signal 2021; 14:eabb5146. [PMID: 33758060 DOI: 10.1126/scisignal.abb5146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Electrostatic interactions regulate many aspects of T cell receptor (TCR) activity, including enabling the dynamic binding of the TCR-associated CD3ε and CD3ζ chains to anionic lipids in the plasma membrane to prevent spontaneous phosphorylation. Substantial changes in the electrostatic potential of the plasma membrane occur at the immunological synapse, the interface between a T cell and an antigen-presenting cell. Here, we investigated how the electrostatic interactions that promote dynamic membrane binding of the TCR-CD3 cytoplasmic domains are modulated during signaling and affect T cell activation. We found that Ca2+-dependent activation of the phosphatidylserine scramblase TMEM16F, which was previously implicated in T cell activation, reduced the electrostatic potential of the plasma membrane during immunological synapse formation by locally redistributing phosphatidylserine. This, in turn, increased the dissociation of bystander TCR-CD3 cytoplasmic domains from the plasma membrane and enhanced TCR-dependent signaling and consequently T cell activation. This study establishes the molecular basis for the role of TMEM16F in bystander TCR-induced signal amplification and identifies enhancement of TMEM16F function as a potential therapeutic strategy for promoting T cell activation.
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Affiliation(s)
- Audrey Connolly
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Rébecca Panes
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Margaux Tual
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Raphaël Lafortune
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Angélique Bellemare-Pelletier
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
| | - Etienne Gagnon
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada.
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
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17
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Seidel J, Leitzke S, Ahrens B, Sperrhacke M, Bhakdi S, Reiss K. Role of ADAM10 and ADAM17 in Regulating CD137 Function. Int J Mol Sci 2021; 22:2730. [PMID: 33800462 PMCID: PMC7962946 DOI: 10.3390/ijms22052730] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/01/2021] [Accepted: 03/05/2021] [Indexed: 12/20/2022] Open
Abstract
Human CD137 (4-1BB), a member of the TNF receptor family, and its ligand CD137L (4-1BBL), are expressed on immune cells and tumor cells. CD137/CD137L interaction mediates bidirectional cellular responses of potential relevance in inflammatory diseases, autoimmunity and oncology. A soluble form of CD137 exists, elevated levels of which have been reported in patients with rheumatoid arthritis and various malignancies. Soluble CD137 (sCD137) is considered to represent a splice variant of CD137. In this report, however, evidence is presented that A Disintegrin and Metalloproteinase (ADAM)10 and potentially also ADAM17 are centrally involved in its generation. Release of sCD137 by transfected cell lines and primary T cells was uniformly inhibitable by ADAM10 inhibition. The shedding function of ADAM10 can be blocked through inhibition of its interaction with surface exposed phosphatidylserine (PS), and this effectively inhibited sCD137 generation. The phospholipid scramblase Anoctamin-6 (ANO6) traffics PS to the outer membrane and thus modifies ADAM10 function. Overexpression of ANO6 increased stimulated shedding, and hyperactive ANO6 led to maximal constitutive shedding of CD137. sCD137 was functionally active and augmented T cell proliferation. Our findings shed new light on the regulation of CD137/CD137L immune responses with potential impact on immunotherapeutic approaches targeting CD137.
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Affiliation(s)
- Jana Seidel
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (J.S.); (S.L.); (B.A.); (M.S.)
| | - Sinje Leitzke
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (J.S.); (S.L.); (B.A.); (M.S.)
| | - Björn Ahrens
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (J.S.); (S.L.); (B.A.); (M.S.)
| | - Maria Sperrhacke
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (J.S.); (S.L.); (B.A.); (M.S.)
| | | | - Karina Reiss
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (J.S.); (S.L.); (B.A.); (M.S.)
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18
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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19
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Roh JW, Hwang GE, Kim WK, Nam JH. Ca 2+ Sensitivity of Anoctamin 6/TMEM16F Is Regulated by the Putative Ca 2+-Binding Reservoir at the N-Terminal Domain. Mol Cells 2021; 44:88-100. [PMID: 33658434 PMCID: PMC7941003 DOI: 10.14348/molcells.2021.2203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/05/2021] [Accepted: 01/26/2021] [Indexed: 11/27/2022] Open
Abstract
Anoctamin 6/TMEM16F (ANO6) is a dual-function protein with Ca2+-activated ion channel and Ca2+-activated phospholipid scramblase activities, requiring a high intracellular Ca2+ concentration (e.g., half-maximal effective Ca2+ concentration [EC50] of [Ca2+]i > 10 μM), and strong and sustained depolarization above 0 mV. Structural comparison with Anoctamin 1/TMEM16A (ANO1), a canonical Ca2+- activated chloride channel exhibiting higher Ca2+ sensitivity (EC50 of 1 μM) than ANO6, suggested that a homologous Ca2+-transferring site in the N-terminal domain (Nt) might be responsible for the differential Ca2+ sensitivity and kinetics of activation between ANO6 and ANO1. To elucidate the role of the putative Ca2+-transferring reservoir in the Nt (Nt-CaRes), we constructed an ANO6-1-6 chimera in which Nt-CaRes was replaced with the corresponding domain of ANO1. ANO6- 1-6 showed higher sensitivity to Ca2+ than ANO6. However, neither the speed of activation nor the voltage-dependence differed between ANO6 and ANO6-1-6. Molecular dynamics simulation revealed a reduced Ca2+ interaction with Nt- CaRes in ANO6 than ANO6-1-6. Moreover, mutations on potentially Ca2+-interacting acidic amino acids in ANO6 Nt- CaRes resulted in reduced Ca2+ sensitivity, implying direct interactions of Ca2+ with these residues. Based on these results, we cautiously suggest that the net charge of Nt- CaRes is responsible for the difference in Ca2+ sensitivity between ANO1 and ANO6.
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Affiliation(s)
- Jae Won Roh
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea
| | - Ga Eun Hwang
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea
| | - Woo Kyung Kim
- Department of Internal Medicine, Graduate School of Medicine, Dongguk University, Goyang 10326, Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Korea
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20
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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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21
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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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22
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Lu S, Dai M, Hu X, Yi H, Zhang Y. A new survival model based on ion channel genes for prognostic prediction in hepatocellular carcinoma. Genomics 2020; 113:171-182. [PMID: 33340691 DOI: 10.1016/j.ygeno.2020.12.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/30/2020] [Accepted: 12/15/2020] [Indexed: 01/05/2023]
Abstract
Accumulating studies revealed the vital role of ion channels in cancers, but the prognosis role of ion channels in hepatocellular carcinoma (HCC) remains limited. Here, we developed and validated an ion channel signature for prognostic prediction of HCC patients. In total, 35 differential expressed ion channel genes (DEChannelGs) were identified in HCC and a novel ion channel risk model was established for HCC prognosis prediction using the TCGA cohort, which was validated using the ICGC cohort. Moreover, this risk model was an independent prognostic factor and was associated with the immune microenvironment in HCC. Finally, the mRNA and protein levels of ANO10 and CLCN2 were prominently up-regulated and were related to the poor prognosis of HCC patients. Taken together, these results indicated a novel ion channel risk model as a prognostic biomarker for HCC patients and provided further insight into its immunoregulatory mechanism in HCC progression.
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Affiliation(s)
- Shanshan Lu
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, 87# Xiangya Road, Changsha, Hunan 410008, China; The Higher Educational Key Laboratory for Cancer Proteomics and Translational Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Minhui Dai
- Department of Ophthalmology, Xiangya Hospital, Central South University, 87# Xiangya Road, Changsha, Hunan 410008, China
| | - Xingwang Hu
- Department of Infectious Diseases/ Key Laboratory of Viral Hepatitis, Xiangya Hospital, Central South University, 87# Xiangya Road, Changsha, Hunan 41008, China.
| | - Hong Yi
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, 87# Xiangya Road, Changsha, Hunan 410008, China; The Higher Educational Key Laboratory for Cancer Proteomics and Translational Medicine of Hunan Province, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Yiya Zhang
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
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23
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Abstract
Communication between organelles is essential for their cellular homeostasis. Neurodegeneration reflects the declining ability of neurons to maintain cellular homeostasis over a lifetime, where the endolysosomal pathway plays a prominent role by regulating protein and lipid sorting and degradation. Here we report that TMEM16K, an endoplasmic reticulum lipid scramblase causative for spinocerebellar ataxia (SCAR10), is an interorganelle regulator of the endolysosomal pathway. We identify endosomal transport as a major functional cluster of TMEM16K in proximity biotinylation proteomics analyses. TMEM16K forms contact sites with endosomes, reconstituting split-GFP with the small GTPase RAB7. Our study further implicates TMEM16K lipid scrambling activity in endosomal sorting at these sites. Loss of TMEM16K function led to impaired endosomal retrograde transport and neuromuscular function, one of the symptoms of SCAR10. Thus, TMEM16K-containing ER-endosome contact sites represent clinically relevant platforms for regulating endosomal sorting.
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Affiliation(s)
- Maja Petkovic
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA.
| | - Juan Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Lily Yeh Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Yuh Nung Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA.
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA.
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24
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Öhlinger T, Müllner EW, Fritz M, Sauer T, Werning M, Baron DM, Salzer U. Lysophosphatidic acid-induced pro-thrombotic phosphatidylserine exposure and ionophore-induced microvesiculation is mediated by the scramblase TMEM16F in erythrocytes. Blood Cells Mol Dis 2020; 83:102426. [PMID: 32222693 DOI: 10.1016/j.bcmd.2020.102426] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/12/2020] [Accepted: 03/12/2020] [Indexed: 12/31/2022]
Abstract
Recent studies indicate that erythrocytes actively modulate blood clotting and thrombus formation. The lipid mediator lysophosphatidic acid (LPA) is produced by activated platelets, and triggers a signaling process in erythrocytes. This results in cellular calcium uptake and exposure of phosphatidylserine (PS) at the cell surface, thereby generating activated membrane binding sites for factors of the clotting cascade. Moreover, erythrocytes of patients with a bleeding disorder and mutations in the scramblase TMEM16F show impaired PS exposure and microvesiculation upon treatment with calcium ionophore. We report that TMEM16F inhibitors tannic acid (TA) and epigallocatechin-3-gallate (EGCG) inhibit LPA-induced PS exposure and calcium uptake at low micromolar concentrations; fluoxetine, an antidepressant and a known activator of TMEM16F, enhances these processes. These effectors likewise modulate erythrocyte PS exposure and microvesicle shedding induced by calcium ionophore treatment. Further, LPA-treated erythrocytes triggered thrombin generation in platelet-free plasma which was partially impaired in the presence of TA and EGCG. Thus, this study suggests that LPA activates the scramblase TMEM16F in erythrocytes, thereby possibly mediating a pro-thrombotic function in these cells. EGCG as well as fluoxetine, substances with potentially high plasma concentrations due to alimentation or medical treatment, should be considered as potential effectors of systemic hemostatic regulation.
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Affiliation(s)
- Thomas Öhlinger
- Center for Medical Biochemistry, Max Perutz Laboratories, Medical University of Vienna, Vienna, Austria; Department of Anaesthesia, Intensive Care Medicine and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Ernst W Müllner
- Center for Medical Biochemistry, Max Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Magdalena Fritz
- Center for Medical Biochemistry, Max Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Thomas Sauer
- Center for Medical Biochemistry, Max Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Maike Werning
- Center for Medical Biochemistry, Max Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - David M Baron
- Department of Anaesthesia, Intensive Care Medicine and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Ulrich Salzer
- Center for Medical Biochemistry, Max Perutz Laboratories, Medical University of Vienna, Vienna, Austria.
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25
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Zhang Y, Le T, Grabau R, Mohseni Z, Kim H, Natale DR, Feng L, Pan H, Yang H. TMEM16F phospholipid scramblase mediates trophoblast fusion and placental development. Sci Adv 2020; 6:eaba0310. [PMID: 32494719 PMCID: PMC7202889 DOI: 10.1126/sciadv.aba0310] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 02/19/2020] [Indexed: 05/12/2023]
Abstract
Cell-cell fusion or syncytialization is fundamental to the reproduction, development, and homeostasis of multicellular organisms. In addition to various cell type-specific fusogenic proteins, cell surface externalization of phosphatidylserine (PS), a universal eat-me signal in apoptotic cells, has been observed in different cell fusion events. Nevertheless, the molecular underpinnings of PS externalization and cellular mechanisms of PS-facilitated cell-cell fusion are unclear. Here, we report that TMEM16F, a Ca2+-activated phospholipid scramblase (CaPLSase), plays an essential role in placental trophoblast fusion by translocating PS to cell surface independent of apoptosis. The placentas from the TMEM16F knockout mice exhibit deficiency in trophoblast syncytialization and placental development, which lead to perinatal lethality. We thus identified a new biological function of TMEM16F CaPLSase in trophoblast fusion and placental development. Our findings provide insight into understanding cell-cell fusion mechanism of other cell types and on mitigating pregnancy complications such as miscarriage, intrauterine growth restriction, and preeclampsia.
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Affiliation(s)
- Yang Zhang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC, USA
| | - Trieu Le
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Ryan Grabau
- The USF Health Heart Institute, University of South Florida, Tampa, FL, USA
| | - Zahra Mohseni
- Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, USA
| | - Hoejeong Kim
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Diego, La Jolla, CA, USA
| | - David R. Natale
- Departments of Obstetrics and Gynaecology and Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Liping Feng
- Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, USA
- MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Hua Pan
- The USF Health Heart Institute, University of South Florida, Tampa, FL, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC, USA
- Corresponding author.
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26
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Nguyen DM, Chen LS, Jeng G, Yu WP, Chen TY. Cobalt ion interaction with TMEM16A calcium-activated chloride channel: Inhibition and potentiation. PLoS One 2020; 15:e0231812. [PMID: 32302365 PMCID: PMC7164836 DOI: 10.1371/journal.pone.0231812] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/01/2020] [Indexed: 11/22/2022] Open
Abstract
TMEM16A, a Ca2+-sensitive Cl- channel, plays key roles in many physiological functions related to Cl- transport across lipid membranes. Activation of this channel is mediated via binding intracellular Ca2+ to the channel with a relatively high apparent affinity, roughly in the sub-μM to low μM concentration range. Recently available high-resolution structures of TMEM16 molecules reveal that the high-affinity Ca2+ activation sites are formed by several acidic amino acids, using their negatively charged sidechain carboxylates to coordinate the bound Ca2+. In this study, we examine the interaction of TMEM16A with a divalent cation, Co2+, which by itself cannot activate current in TMEM16A. This divalent cation, however, has two effects when applied intracellularly. It inhibits the Ca2+-induced TMEM16A current by competing with Ca2+ for the aforementioned high-affinity activation sites. In addition, Co2+ also potentiates the Ca2+-induced current with a low affinity. This potentiation effect requires high concentration (mM) of Co2+, similar to our previous findings that high concentrations (mM) of intracellular Ca2+ ([Ca2+]i) can induce more TMEM16A current after the Ca2+-activation sites are saturated by tens of μM [Ca2+]i. The degrees of potentiation by Co2+ and Ca2+ also roughly correlate with each other. Interestingly, mutating a pore residue of TMEM16A, Y589, alters the degree of potentiation in that the smaller the sidechain of the replaced residue, the larger the potentiation induced by divalent cations. We suggest that the Co2+ potentiation and the Ca2+ potentiation share a similar mechanism by increasing Cl- flux through the channel pore, perhaps due to an increase of positive pore potential after the binding of divalent cations to phospholipids in the pore. A smaller sidechain of a pore residue may allow the pore to accommodate more phospholipids, thus enhancing the current potentiation caused by high concentrations of divalent cations.
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Affiliation(s)
- Dung M. Nguyen
- Center for Neuroscience, University of California, Davis, California, United States of America
| | - Louisa S. Chen
- Center for Neuroscience, University of California, Davis, California, United States of America
| | - Grace Jeng
- Center for Neuroscience, University of California, Davis, California, United States of America
| | - Wei-Ping Yu
- Center for Neuroscience, University of California, Davis, California, United States of America
| | - Tsung-Yu Chen
- Center for Neuroscience, University of California, Davis, California, United States of America
- Department of Neurology, University of California, Davis, California, United States of America
- * E-mail:
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27
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Khelashvili G, Cheng X, Falzone ME, Doktorova M, Accardi A, Weinstein H. Membrane lipids are both the substrates and a mechanistically responsive environment of TMEM16 scramblase proteins. J Comput Chem 2020; 41:538-551. [PMID: 31750558 PMCID: PMC7261202 DOI: 10.1002/jcc.26105] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/04/2019] [Accepted: 10/17/2019] [Indexed: 12/21/2022]
Abstract
Recent discoveries about functional mechanisms of proteins in the TMEM16 family of phospholipid scramblases have illuminated the dual role of the membrane as both the substrate and a mechanistically responsive environment in the wide range of physiological processes and genetic disorders in which they are implicated. This is highlighted in the review of recent findings from our collaborative investigations of molecular mechanisms of TMEM16 scramblases that emerged from iterative functional, structural, and computational experimentation. In the context of this review, we present new MD simulations and trajectory analyses motivated by the fact that new structural information about the TMEM16 scramblases is emerging from cryo-EM determinations in lipid nanodiscs. Because the functional environment of these proteins in in vivo and in in vitro is closer to flat membranes, we studied comparatively the responses of the membrane to the TMEM16 proteins in flat membranes and nanodiscs. We find that bilayer shapes in the nanodiscs are very different from those observed in the flat membrane systems, but the function-related slanting of the membrane observed at the nhTMEM16 boundary with the protein is similar in the nanodiscs and in the flat bilayers. This changes, however, in the bilayer composed of longer-tail lipids, which is thicker near the phospholipid translocation pathway, which may reflect an enhanced tendency of the long tails to penetrate the pathway and create, as shown previously, a nonconductive environment. These findings support the correspondence between the mechanistic involvement of the lipid environment in the flat membranes, and the nanodiscs. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, 10065
- Institute for Computational Biomedicine, Weill Cornell Medical College of Cornell University, New York, New York, 10065
| | - Xiaolu Cheng
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, 10065
| | - Maria E Falzone
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, New York, 10065
| | - Milka Doktorova
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, 77030
| | - Alessio Accardi
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, 10065
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, New York, 10065
- Department of Anesthesiology, Weill Cornell Medical College of Cornell University, New York, New York, 10065
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, 10065
- Institute for Computational Biomedicine, Weill Cornell Medical College of Cornell University, New York, New York, 10065
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28
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Wu N, Cernysiov V, Davidson D, Song H, Tang J, Luo S, Lu Y, Qian J, Gyurova IE, Waggoner SN, Trinh VQH, Cayrol R, Sugiura A, McBride HM, Daudelin JF, Labrecque N, Veillette A. Critical Role of Lipid Scramblase TMEM16F in Phosphatidylserine Exposure and Repair of Plasma Membrane after Pore Formation. Cell Rep 2020; 30:1129-1140.e5. [PMID: 31995754 PMCID: PMC7104872 DOI: 10.1016/j.celrep.2019.12.066] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/25/2019] [Accepted: 12/17/2019] [Indexed: 01/01/2023] Open
Abstract
Plasma membrane damage and cell death during processes such as necroptosis and apoptosis result from cues originating intracellularly. However, death caused by pore-forming agents, like bacterial toxins or complement, is due to direct external injury to the plasma membrane. To prevent death, the plasma membrane has an intrinsic repair ability. Here, we found that repair triggered by pore-forming agents involved TMEM16F, a calcium-activated lipid scramblase also mutated in Scott's syndrome. Upon pore formation and the subsequent influx of intracellular calcium, TMEM16F induced rapid "lipid scrambling" in the plasma membrane. This response was accompanied by membrane blebbing, extracellular vesicle release, preserved membrane integrity, and increased cell viability. TMEM16F-deficient mice exhibited compromised control of infection by Listeria monocytogenes associated with a greater sensitivity of neutrophils to the pore-forming Listeria toxin listeriolysin O (LLO). Thus, the lipid scramblase TMEM16F is critical for plasma membrane repair after injury by pore-forming agents.
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Affiliation(s)
- Ning Wu
- Laboratory of Molecular Oncology, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W1R7, Canada; Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, China; Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology (HUST), Wuhan, China.
| | - Vitalij Cernysiov
- Laboratory of Molecular Oncology, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W1R7, Canada
| | - Dominique Davidson
- Laboratory of Molecular Oncology, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W1R7, Canada
| | - Hua Song
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Jianlong Tang
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Shanshan Luo
- Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Yan Lu
- Laboratory of Molecular Oncology, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W1R7, Canada
| | - Jin Qian
- Laboratory of Molecular Oncology, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W1R7, Canada
| | - Ivayla E Gyurova
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Pathobiology and Molecular Medicine Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Stephen N Waggoner
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Pathobiology and Molecular Medicine Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Vincent Quoc-Huy Trinh
- Department of Pathology and Cellular Biology, University of Montreal, Montreal, QC, Canada
| | - Romain Cayrol
- Department of Pathology and Cellular Biology, University of Montreal, Montreal, QC, Canada
| | - Ayumu Sugiura
- Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - Heidi M McBride
- Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | | | - Nathalie Labrecque
- Maisonneuve-Rosemont Hospital Research Center, Montréal, QC, Canada; Department of Medicine, University of Montréal, Montréal, QC H3C3J7, Canada; Department of Microbiology, Infectious Diseases and Immunology, University of Montréal, Montréal, QC H3C3J7, Canada
| | - André Veillette
- Laboratory of Molecular Oncology, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W1R7, Canada; Maisonneuve-Rosemont Hospital Research Center, Montréal, QC, Canada; Department of Medicine, McGill University, Montréal, QC H3G 1Y6, Canada.
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29
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Abstract
Single-particle cryo-electron microscopy has become an indispensable technique in structural biology. In particular when studying membrane proteins, it allows the use of membrane-mimicking tools, which can be crucial for a comprehensive understanding of the structure-function relationship of the protein in its native environment. In this chapter we focus on the application of nanodiscs and use our recent studies on the TMEM16 family as an example.
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Affiliation(s)
- Valeria Kalienkova
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Carolina Alvadia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Vanessa Clerico Mosina
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Cristina Paulino
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
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Cabrita I, Benedetto R, Schreiber R, Kunzelmann K. Niclosamide repurposed for the treatment of inflammatory airway disease. JCI Insight 2019; 4:128414. [PMID: 31391337 DOI: 10.1172/jci.insight.128414] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/02/2019] [Indexed: 12/22/2022] Open
Abstract
Inflammatory airway diseases, such as asthma, cystic fibrosis (CF), and chronic obstructive pulmonary disease (COPD), are characterized by mucus hypersecretion and airway plugging. In both CF and asthma, enhanced expression of the Ca2+-activated Cl- channel TMEM16A is detected in mucus-producing club/goblet cells and airway smooth muscle. TMEM16A contributes to mucus hypersecretion and bronchoconstriction, which are both inhibited by blockers of TMEM16A, such as niflumic acid. Here we demonstrate that the FDA-approved drug niclosamide, a potent inhibitor of TMEM16A identified by high-throughput screening, is an inhibitor of both TMEM16A and TMEM16F. In asthmatic mice, niclosamide reduced mucus production and secretion, as well as bronchoconstriction, and showed additional antiinflammatory effects. Using transgenic asthmatic mice, we found evidence that TMEM16A and TMEM16F are required for normal mucus production/secretion, which may be due to their effects on intracellular Ca2+ signaling. TMEM16A and TMEM16F support exocytic release of mucus and inflammatory mediators, both of which are blocked by niclosamide. Thus, inhibition of mucus and cytokine release, bronchorelaxation, and reported antibacterial effects make niclosamide a potentially suitable drug for the treatment of inflammatory airway diseases, such as CF, asthma, and COPD.
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31
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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32
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Tsuji T, Cheng J, Tatematsu T, Ebata A, Kamikawa H, Fujita A, Gyobu S, Segawa K, Arai H, Taguchi T, Nagata S, Fujimoto T. Predominant localization of phosphatidylserine at the cytoplasmic leaflet of the ER, and its TMEM16K-dependent redistribution. Proc Natl Acad Sci U S A 2019; 116:13368-13373. [PMID: 31217287 PMCID: PMC6613088 DOI: 10.1073/pnas.1822025116] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
TMEM16K, a membrane protein carrying 10 transmembrane regions, has phospholipid scramblase activity. TMEM16K is localized to intracellular membranes, but whether it actually scrambles phospholipids inside cells has not been demonstrated, due to technical difficulties in studying intracellular lipid distributions. Here, we developed a freeze-fracture electron microscopy method that enabled us to determine the phosphatidylserine (PtdSer) distribution in the individual leaflets of cellular membranes. Using this method, we found that the endoplasmic reticulum (ER) of mammalian cells harbored abundant PtdSer in its cytoplasmic leaflet and much less in the luminal leaflet, whereas the outer and inner nuclear membranes (NMs) had equivalent amounts of PtdSer in both leaflets. The ER and NMs of budding yeast also harbored PtdSer in their cytoplasmic leaflet, but asymmetrical distribution in the ER was not observed. Treating mouse embryonic fibroblasts with the Ca2+ ionophore A23187 compromised the cytoplasmic leaflet-dominant PtdSer asymmetry in the ER and increased PtdSer in the NMs, especially in the nucleoplasmic leaflet of the inner NM. This Ca2+-induced PtdSer redistribution was not observed in TMEM16K-null fibroblasts, but was recovered in these cells by reexpressing TMEM16K. These results indicate that, similar to the plasma membrane, PtdSer in the ER of mammalian cells is predominantly localized to the cytoplasmic leaflet, and that TMEM16K directly or indirectly mediates Ca2+-dependent phospholipid scrambling in the ER.
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Affiliation(s)
- Takuma Tsuji
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 466-8550 Nagoya, Japan
| | - Jinglei Cheng
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 466-8550 Nagoya, Japan
| | - Tsuyako Tatematsu
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 466-8550 Nagoya, Japan
| | - Aoi Ebata
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 466-8550 Nagoya, Japan
| | - Hiroki Kamikawa
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 466-8550 Nagoya, Japan
| | - Akikazu Fujita
- Field of Veterinary Pathobiology, Joint Faculty of Veterinary Medicine, Kagoshima University, 890-0065 Kagoshima, Japan
| | - Sayuri Gyobu
- Biochemistry and Immunology, Immunology Frontier Research Center, Osaka University, Suita 565-0871, Japan
| | - Katsumori Segawa
- Biochemistry and Immunology, Immunology Frontier Research Center, Osaka University, Suita 565-0871, Japan
| | - Hiroyuki Arai
- Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 113-0033 Tokyo, Japan
| | - Tomohiko Taguchi
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, 980-8578 Sendai, Japan
| | - Shigekazu Nagata
- Biochemistry and Immunology, Immunology Frontier Research Center, Osaka University, Suita 565-0871, Japan
| | - Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 466-8550 Nagoya, Japan;
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Benedetto R, Ousingsawat J, Cabrita I, Pinto M, Lérias JR, Wanitchakool P, Schreiber R, Kunzelmann K. Plasma membrane-localized TMEM16 proteins are indispensable for expression of CFTR. J Mol Med (Berl) 2019; 97:711-722. [PMID: 30915480 DOI: 10.1007/s00109-019-01770-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 02/22/2019] [Accepted: 03/05/2019] [Indexed: 10/27/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is the secretory chloride channel in epithelial tissues that has a central role in cystic fibrosis (CF) lung and gastrointestinal disease. A recent publication demonstrates a close association between CFTR and TMEM16A, the calcium-activated chloride channel. Thus, no CFTR chloride currents could be detected in airways and large intestine from mice lacking epithelial expression of TMEM16A. Here, we demonstrate that another plasma membrane-localized TMEM16 paralogue, TMEM16F, can compensate for the lack of TMEM16A. Using TMEM16 knockout mice, human lymphocytes, and a number of human cell lines with endogenous protein expression or heterologous expression, we demonstrate that CFTR can only function in the presence of either TMEM16A or TMEM16F. Double knockout of intestinal epithelial TMEM16A/F expression did not produce offsprings, suggesting a lethal phenotype in utero. Plasma membrane-localized TMEM16A or TMEM16F is required for exocytosis and expression of CFTR in the plasma membrane. TMEM16A/F proteins may therefore have an impact on disease severity in CF. KEY MESSAGES: • Cystic fibrosis is caused by the defective Cl- channel cystic fibrosis transmembrane conductance regulator (CFTR). • A close relationship exists between CFTR and the calcium-activated chloride channels TMEM16A/TMEM16F. • In conditional airway and intestinal knockout mice, lymphocytes from Scott disease patients and in overexpressing cells, CFTR is not functional in the absence of TMEM16A and TMEM16F. • TMEM16A and TMEM16F support membrane exocytosis and are essential for plasma membrane insertion of CFTR.
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Affiliation(s)
- Roberta Benedetto
- 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
| | - Inês Cabrita
- Physiological Institute, University of Regensburg, University Street 31, D-93053, Regensburg, Germany
| | - Madalena Pinto
- Physiological Institute, University of Regensburg, University Street 31, D-93053, Regensburg, Germany
| | - Joana R Lérias
- Physiological Institute, University of Regensburg, University Street 31, D-93053, Regensburg, Germany
| | - Podchanart Wanitchakool
- 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
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, University Street 31, D-93053, Regensburg, Germany.
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Lin H, Jun I, Woo JH, Lee MG, Kim SJ, Nam JH. Temperature-dependent increase in the calcium sensitivity and acceleration of activation of ANO6 chloride channel variants. Sci Rep 2019; 9:6706. [PMID: 31040335 PMCID: PMC6491614 DOI: 10.1038/s41598-019-43162-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 04/12/2019] [Indexed: 02/08/2023] Open
Abstract
Anoctamin-6 (ANO6) belongs to a family of calcium (Ca2+)-activated chloride channels (CaCCs), with three splicing variants (V1, V2, and V5) showing plasma membrane expression. Unlike other CaCCs, ANO6 requires a non-physiological intracellular free calcium concentration ([Ca2+]i > 1 μM) and several minutes for full activation under a whole-cell patch clamp. Therefore, its physiological role as an ion channel is uncertain and it is more commonly considered a Ca2+-dependent phospholipid scramblase. Here, we demonstrate that physiological temperature (37 °C) increases ANO6 Ca2+ sensitivity under a whole-cell patch clamp; V1 was activated by 1 μM [Ca2+]i, whereas V2 and V5 were activated by 300 nM [Ca2+]i. Increasing the temperature to 42 °C led to activation of all ANO6 variants by 100 nM [Ca2+]i. The delay time for activation of the three variants was significantly shortened at 37 °C. Notably, the temperature-dependent Ca2+-sensitisation of ANO6 became insignificant under inside-out patch clamp, suggesting critical roles of unknown cytosolic factors. Unlike channel activity, 27 °C but not 37 °C (physiological temperature) induced the scramblase activity of ANO6 at submicromolar [Ca2+]i (300 nM), irrespective of variant type. Our results reveal a physiological ion conducting property of ANO6 at 37 °C and suggest that ANO6 channel function acts separately from its scramblase activity.
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Affiliation(s)
- Haiyue Lin
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Ikhyun Jun
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Joo Han Woo
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju, 38066, Republic of Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang, Gyeonggi-do, 10326, Republic of Korea
| | - Min Goo Lee
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju, 38066, Republic of Korea.
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang, Gyeonggi-do, 10326, Republic of Korea.
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35
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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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36
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Tong JJ, Acharya P, Ebihara L. Calcium-Activated Chloride Channels in Newly Differentiating Mouse Lens Fiber Cells and Their Role in Volume Regulation. Invest Ophthalmol Vis Sci 2019; 60:1621-1629. [PMID: 30995319 PMCID: PMC6736345 DOI: 10.1167/iovs.19-26626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/14/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose Chloride channels have been proposed to play an important role in the regulation of lens volume. Unfortunately, little information is available about the molecular identity of these channels or how they are regulated in the lens due to the difficulties in isolating mouse fiber cells. Recently, our laboratory has developed a new technique for isolating these cells by using transgenic mouse lenses that lack both Cx50 and Cx46. The purpose of this study was to test the hypothesis that newly differentiating mouse fiber cells express calcium-activated chloride channels (CaCCs) by using this technique. Methods Differentiating fiber cells were isolated from lenses of double knockout mice that lack both Cx50 and Cx46 by using collagenase. Membrane currents were studied using the whole-cell patch clamp technique. The molecular identity and distribution of CaCCs were investigated using RT-PCR and immunofluorescence. Results Our electrophysiologic experiments suggest that peripheral fiber cells express a calcium-activated chloride current. The voltage gating properties, calcium sensitivity, and pharmacologic properties of this current resembled those of TMEM16 CaCCs. RT-PCR analysis demonstrated the presence of TMEM16A and TMEM16B transcripts in wild-type and double knockout mouse lenses. Both TMEM16A and TMEM16B proteins were detected in the differentiating epithelial cells and newly elongating fiber cells near the equator of the lens by immunohistochemistry. Conclusions Our results demonstrate that membrane conductance of peripheral fiber cells contain CaCCs that can be attributed to TMEM16A and TMEM16B. Given their critical role in volume regulation in other tissues, we speculate that these channels play a similar role in the lens.
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Affiliation(s)
- Jun-Jie Tong
- Department of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, Chicago, Illinois, United States
| | - Pooja Acharya
- Department of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, Chicago, Illinois, United States
| | - Lisa Ebihara
- Department of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, Chicago, Illinois, United States
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37
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Kim JH, Kim K, Kim I, Seong S, Kim SW, Kim N. Role of anoctamin 5, a gene associated with gnathodiaphyseal dysplasia, in osteoblast and osteoclast differentiation. Bone 2019; 120:432-438. [PMID: 30557634 DOI: 10.1016/j.bone.2018.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/04/2018] [Accepted: 12/13/2018] [Indexed: 12/16/2022]
Abstract
Anoctamin 5 (Ano5) mutations are responsible for gnathodiaphyseal dysplasia, a rare skeletal syndrome. Despite the close linkage of Ano5 to bone remodeling, the molecular mechanisms underlying the role of Ano5 in bone remodeling remain unknown. In this study, we investigated whether Ano5 regulates osteoblast or osteoclast differentiation to maintain normal bone remodeling. Downregulation of Ano5 expression did not affect osteoblast differentiation and mineralization, while ectopic expression of Ano5 significantly enhanced receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation. Furthermore, Ano5-mediated Akt phosphorylation resulted in nuclear factor of activated T-cells c1 (NFATc1) activation, indicating that Ano5 regulates osteoclast differentiation through activation of the Akt-NFATc1 signaling pathway. Thus, our results suggest a possibility that Ano5 is involved in bone remodeling through regulating the function of osteoclasts rather than that of osteoblasts.
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Affiliation(s)
- Jung Ha Kim
- Department of Pharmacology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea
| | - Kabsun Kim
- Department of Pharmacology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea
| | - Inyoung Kim
- Department of Pharmacology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea
| | - Semun Seong
- Department of Pharmacology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea; Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju 61469, Republic of Korea
| | - Sang Wan Kim
- Department of Internal Medicine, Seoul National University College of Medicine and Boramae Medical Center, Seoul 07061, Republic of Korea
| | - Nacksung Kim
- Department of Pharmacology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea; Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju 61469, Republic of Korea.
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Bricogne C, Fine M, Pereira PM, Sung J, Tijani M, Wang Y, Henriques R, Collins MK, Hilgemann DW. TMEM16F activation by Ca 2+ triggers plasma membrane expansion and directs PD-1 trafficking. Sci Rep 2019; 9:619. [PMID: 30679690 PMCID: PMC6345885 DOI: 10.1038/s41598-018-37056-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/03/2018] [Indexed: 12/22/2022] Open
Abstract
TMEM16F is a Ca2+ -gated ion channel that is required for Ca2+ -activated phosphatidylserine exposure on the surface of many eukaryotic cells. TMEM16F is widely expressed and has roles in platelet activation during blood clotting, bone formation and T cell activation. By combining microscopy and patch clamp recording we demonstrate that activation of TMEM16F by Ca2+ ionophores in Jurkat T cells triggers large-scale surface membrane expansion in parallel with phospholipid scrambling. With continued ionophore application,TMEM16F-expressing cells then undergo extensive shedding of ectosomes. The T cell co-receptor PD-1 is selectively incorporated into ectosomes. This selectivity depends on its transmembrane sequence. Surprisingly, cells lacking TMEM16F not only fail to expand surface membrane in response to elevated cytoplasmic Ca2+, but instead undergo rapid massive endocytosis with PD-1 internalisation. These results establish a new role for TMEM16F as a regulator of Ca2+ activated membrane trafficking.
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Affiliation(s)
| | - Michael Fine
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, Texas, USA
| | - Pedro M Pereira
- MRC Laboratory for Molecular Cell Biology, University College London, Gower St, London, UK
| | - Julia Sung
- National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Herts, UK
| | - Maha Tijani
- National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Herts, UK
| | - Youxue Wang
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, Texas, USA
| | - Ricardo Henriques
- MRC Laboratory for Molecular Cell Biology, University College London, Gower St, London, UK
| | - Mary K Collins
- UCL Cancer Institute, University College London, Gower St, London, UK.
- National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Herts, UK.
- Okinawa Institute of Science and Technology, Onna-son, Okinawa, Japan.
| | - Donald W Hilgemann
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, Texas, USA.
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Han TW, Ye W, Bethel NP, Zubia M, Kim A, Li KH, Burlingame AL, Grabe M, Jan YN, Jan LY. Chemically induced vesiculation as a platform for studying TMEM16F activity. Proc Natl Acad Sci U S A 2019; 116:1309-1318. [PMID: 30622179 PMCID: PMC6347726 DOI: 10.1073/pnas.1817498116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Calcium-activated phospholipid scramblase mediates the energy-independent bidirectional translocation of lipids across the bilayer, leading to transient or, in the case of apoptotic scrambling, sustained collapse of membrane asymmetry. Cells lacking TMEM16F-dependent lipid scrambling activity are deficient in generation of extracellular vesicles (EVs) that shed from the plasma membrane in a Ca2+-dependent manner, namely microvesicles. We have adapted chemical induction of giant plasma membrane vesicles (GPMVs), which require both TMEM16F-dependent phospholipid scrambling and calcium influx, as a kinetic assay to investigate the mechanism of TMEM16F activity. Using the GPMV assay, we identify and characterize both inactivating and activating mutants that elucidate the mechanism for TMEM16F activation and facilitate further investigation of TMEM16F-mediated lipid translocation and its role in extracellular vesiculation.
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Affiliation(s)
- Tina W Han
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Wenlei Ye
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Neville P Bethel
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94143
| | - Mario Zubia
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Andrew Kim
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Kathy H Li
- Mass Spectrometry Facility, University of California, San Francisco, CA 94143
| | - Alma L Burlingame
- Mass Spectrometry Facility, University of California, San Francisco, CA 94143
| | - Michael Grabe
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94143
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Lily Y Jan
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143;
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
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40
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Abstract
The distribution of different lipid species between the two leaflets is tightly regulated and underlies the concerted action of distinct catalytic entities. While flippases and floppases establish membrane asymmetry, scramblases randomize the lipid distribution and play pivotal roles during blood clotting, apoptosis, and in processes such as N-linked glycosylation of proteins. The recent discovery of TMEM16 family members acting as scramblases has led to an increasing demand for developing protocols tailored for TMEM16 proteins to enable functional investigations of their scrambling activity. Here we describe a protocol for the expression, purification, and functional reconstitution of TMEM16 proteins into preformed liposomes and measurement of their scrambling activity using fluorescence-labeled lipid derivatives. The reconstitution involves extrusion of liposomes through a membrane, destabilization of liposomes using Triton X-100, and stepwise detergent removal by adsorption on styryl-beads. The scrambling assay is based on the selective bleaching of nitrobenzoxadiazol fluorescent lipids on the outer leaflet of liposomes by the membrane-impermeant reducing agent sodium dithionite. The assay allows conclusions on the substrate specificity and on the kinetics of the transported lipids as shown with the example of a Ca2+-activated TMEM16 scramblase from the fungus Nectria haematococca (nhTMEM16).
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Affiliation(s)
- Janine Denise Brunner
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen, Switzerland.
| | - Stephan Schenck
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen, Switzerland
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41
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Wang L, Iwasaki Y, Andra KK, Pandey K, Menon AK, Bütikofer P. Scrambling of natural and fluorescently tagged phosphatidylinositol by reconstituted G protein-coupled receptor and TMEM16 scramblases. J Biol Chem 2018; 293:18318-18327. [PMID: 30287690 PMCID: PMC6254352 DOI: 10.1074/jbc.ra118.004213] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 10/03/2018] [Indexed: 12/12/2022] Open
Abstract
Members of the G protein-coupled receptor and TMEM16 (transmembrane protein 16) protein families are phospholipid scramblases that facilitate rapid, bidirectional movement of phospholipids across a membrane bilayer in an ATP-independent manner. On reconstitution into large unilamellar vesicles, these proteins scramble more than 10,000 lipids/protein/s as measured with co-reconstituted fluorescent nitrobenzoxadiazole (NBD)-labeled phospholipids. Although NBD-labeled phospholipids are ubiquitously used as reporters of scramblase activity, it remains unclear whether the NBD modification influences the quantitative outcomes of the scramblase assay. We now report a refined biochemical approach for measuring the activity of scramblase proteins with radiolabeled natural phosphatidylinositol ([3H]PI) and exploiting the hydrolytic activity of bacterial PI-specific phospholipase C (PI-PLC) to detect the transbilayer movement of PI. PI-PLC rapidly hydrolyzed 50% of [3H]PI in large symmetric, unilamellar liposomes, corresponding to the lipid pool in the outer leaflet. On reconstitution of a crude preparation of yeast endoplasmic reticulum scramblase, purified bovine opsin, or purified Nectria haematococca TMEM16, the extent of [3H]PI hydrolysis increased, indicating that [3H]PI from the inner leaflet had been scrambled to the outer leaflet. Using transphosphatidylation, we synthesized acyl-NBD-PI and used it to compare our PI-PLC-based assay with conventional fluorescence-based methods. Our results revealed quantitative differences between the two assays that we attribute to the specific features of the assays themselves rather than to the nature of the phospholipid. In summary, we have developed an assay that measures scrambling of a chemically unmodified phospholipid by a reconstituted scramblase.
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Affiliation(s)
- Lei Wang
- From the Institute of Biochemistry and Molecular Medicine and; Graduate School for Cellular and Biochemical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Yugo Iwasaki
- the Laboratory of Molecular Biotechnology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Nagoya 464-8601, Japan, and
| | - Kiran K Andra
- the Department of Biochemistry, Weill Cornell Medical College, New York, New York 10065
| | - Kalpana Pandey
- the Department of Biochemistry, Weill Cornell Medical College, New York, New York 10065
| | - Anant K Menon
- the Department of Biochemistry, Weill Cornell Medical College, New York, New York 10065.
| | - Peter Bütikofer
- From the Institute of Biochemistry and Molecular Medicine and.
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42
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Veit M, Koyro KI, Ahrens B, Bleibaum F, Munz M, Rövekamp H, Andrä J, Schreiber R, Kunzelmann K, Sommer A, Bhakdi S, Reiss K. Anoctamin-6 regulates ADAM sheddase function. Biochim Biophys Acta Mol Cell Res 2018; 1865:1598-1610. [PMID: 30327201 DOI: 10.1016/j.bbamcr.2018.08.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 08/17/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
ADAM17, a prominent member of the "Disintegrin and Metalloproteinase" (ADAM) family, controls vital cellular functions through cleavage of transmembrane substrates including TGF-alpha, Amphiregulin (AREG) and TNF-Receptor 1 (TNFR1). We recently presented evidence that surface exposure of phosphatidylserine (PS) is pivotal for ADAM17 to exert sheddase activity. Anoctamin-6 (ANO6) has Ca2+-dependent phospholipid scramblase activity and it followed that the functions of ANO6 and ADAM17 might be linked. We report that overexpression of ANO6 in HEK293T cells led to increased Ca2+-mediated PS-exposure that was indeed accompanied by enhanced release of AREG and TGF-alpha. The effect was not observed when cells were treated with the PKC-dependent ADAM17 activator PMA. Transformation of cells with a constitutively active ANO6 mutant led to spontaneous PS-exposure and to the release of ADAM17-substrates in the absence of any stimuli. Inhibitor experiments indicated that ANO6-mediated enhancement of substrate cleavage simultaneously broadened the spectrum of participating metalloproteinases. In complementary experiments, siRNA-mediated downregulation of ANO6 was shown to decrease ionophore-mediated release of TNFR1 in human umbilical vein endothelial cells (HUVECs). We conclude that ANO6, by virtue of its scramblase activity, may play a role as an important regulator of the ADAM-network in the plasma membrane.
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Affiliation(s)
- Martin Veit
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Björn Ahrens
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Martin Munz
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Hagen Rövekamp
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Jörg Andrä
- Hamburg University of Applied Science, Ulmenliet 20, 21033 Hamburg, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Anselm Sommer
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Sucharit Bhakdi
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Karina Reiss
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany.
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43
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Lin H, Roh J, Woo JH, Kim SJ, Nam JH. TMEM16F/ANO6, a Ca 2+-activated anion channel, is negatively regulated by the actin cytoskeleton and intracellular MgATP. Biochem Biophys Res Commun 2018; 503:2348-2354. [PMID: 29964013 DOI: 10.1016/j.bbrc.2018.06.160] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 06/28/2018] [Indexed: 01/08/2023]
Abstract
Anoctamin 6 (ANO6/TMEM16F) is a recently identified membrane protein that has both phospholipid scramblase activity and anion channel function activated by relatively high [Ca2+]i. In addition to the low sensitivity to Ca2+, the activation of ANO6 Cl- conductance is very slow (>3-5 min to reach peak level at 10 μM [Ca2+]i), with subsequent inactivation. In a whole-cell patch clamp recording of ANO6 current (IANO6,w-c), disruption of the actin cytoskeleton with cytochalasin-D (cytoD) significantly accelerated the activation kinetics, while actin filament-stabilizing agents (phalloidin and jasplakinolide) commonly inhibited IANO6,w-c. Inside-out patch clamp recording of ANO6 (IANO6,i-o) showed immediate activation by raising [Ca2+]i. We also found that intracellular ATP (3 mM MgATP in pipette solution) decelerated the activation of IANO6,w-c, and also prevented the inactivation of IANO6,w-c. However, the addition of cytoD still accelerated both activation and inactivation of IANO6,w-c. We conclude that the actin cytoskeleton and intracellular ATP play major roles in the Ca2+-dependent activation and inactivation of IANO6,w-c, respectively.
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Affiliation(s)
- Haiyue Lin
- Department of Physiology, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Jaewon Roh
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju, 38066, Republic of Korea
| | - Joo Han Woo
- Department of Physiology, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju, 38066, Republic of Korea; Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang, Gyeonggi-do, 10326, Republic of Korea.
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44
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Malvezzi M, Andra KK, Pandey K, Lee BC, Falzone ME, Brown A, Iqbal R, Menon AK, Accardi A. Out-of-the-groove transport of lipids by TMEM16 and GPCR scramblases. Proc Natl Acad Sci U S A 2018; 115:E7033-E7042. [PMID: 29925604 PMCID: PMC6065010 DOI: 10.1073/pnas.1806721115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phospholipid scramblases externalize phosphatidylserine to facilitate numerous physiological processes. Several members of the structurally unrelated TMEM16 and G protein-coupled receptor (GPCR) protein families mediate phospholipid scrambling. The structure of a TMEM16 scramblase shows a membrane-exposed hydrophilic cavity, suggesting that scrambling occurs via the ‟credit-card" mechanism where lipid headgroups permeate through the cavity while their tails remain associated with the membrane core. Here we show that afTMEM16 and opsin, representatives of the TMEM16 and GCPR scramblase families, transport phospholipids with polyethylene glycol headgroups whose globular dimensions are much larger than the width of the cavity. This suggests that transport of these large headgroups occurs outside rather than within the cavity. These large lipids are scrambled at rates comparable to those of normal phospholipids and their presence in the reconstituted vesicles promotes scrambling of normal phospholipids. This suggests that both large and small phospholipids can move outside the cavity. We propose that the conformational rearrangements underlying TMEM16- and GPCR-mediated credit-card scrambling locally deform the membrane to allow transbilayer lipid translocation outside the cavity and that both mechanisms underlie transport of normal phospholipids.
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Affiliation(s)
- Mattia Malvezzi
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065
| | - Kiran K Andra
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Kalpana Pandey
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Byoung-Cheol Lee
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065
| | - Maria E Falzone
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Ashley Brown
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Rabia Iqbal
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Alessio Accardi
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065;
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10065
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45
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Stewart SE, Ashkenazi A, Williamson A, Rubinsztein DC, Moreau K. Transbilayer phospholipid movement facilitates the translocation of annexin across membranes. J Cell Sci 2018; 131:jcs217034. [PMID: 29930080 PMCID: PMC6080606 DOI: 10.1242/jcs.217034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/06/2018] [Indexed: 02/03/2023] Open
Abstract
Annexins are cytosolic phospholipid-binding proteins that can be found on the outer leaflet of the plasma membrane. The extracellular functions of annexin include modulating fibrinolysis activity and cell migration. Despite having well-described extracellular functions, the mechanism of annexin transport from the cytoplasmic inner leaflet to the extracellular outer leaflet of the plasma membrane remains unclear. Here, we show that the transbilayer movement of phospholipids facilitates the transport of annexins A2 and A5 across membranes in cells and in liposomes. We identified TMEM16F (also known as anoctamin-6, ANO6) as a lipid scramblase required for transport of these annexins to the outer leaflet of the plasma membrane. This work reveals a mechanism for annexin translocation across membranes which depends on plasma membrane phospholipid remodelling.
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Affiliation(s)
- Sarah E Stewart
- University of Cambridge, Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Cambridge, CB2 0QQ, UK
| | - Avraham Ashkenazi
- University of Cambridge, Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
| | - Athena Williamson
- University of Cambridge, Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Cambridge, CB2 0QQ, UK
| | - David C Rubinsztein
- University of Cambridge, Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK
- UK Dementia Research Institute, Cambridge Biomedical Campus, Hills Road, Cambridge, UK
| | - Kevin Moreau
- University of Cambridge, Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Cambridge, CB2 0QQ, UK
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46
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Schenk LK, Ousingsawat J, Skryabin BV, Schreiber R, Pavenstädt H, Kunzelmann K. Regulation and Function of TMEM16F in Renal Podocytes. Int J Mol Sci 2018; 19:ijms19061798. [PMID: 29912162 PMCID: PMC6032267 DOI: 10.3390/ijms19061798] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 06/12/2018] [Accepted: 06/14/2018] [Indexed: 12/13/2022] Open
Abstract
The Ca2+-activated phospholipid scramblase and ion channel TMEM16F is expressed in podocytes of renal glomeruli. Podocytes are specialized cells that form interdigitating foot processes as an essential component of the glomerular filter. These cells, which participate in generation of the primary urine, are often affected during primary glomerular diseases, such as glomerulonephritis and secondary hypertensive or diabetic nephropathy, which always leads to proteinuria. Because the function of podocytes is known to be controlled by intracellular Ca2+ signaling, it is important to know about the role of Ca2+-activated TMEM16F in these cells. To that end, we generated an inducible TMEM16F knockdown in the podocyte cell line AB8, and produced a conditional mouse model with knockout of TMEM16F in podocytes and renal epithelial cells of the nephron. We found that knockdown of TMEM16F did not produce proteinuria or any obvious phenotypic changes. Knockdown of TMEM16F affected cell death of tubular epithelial cells but not of glomerular podocytes when analyzed in TUNEL assays. Surprisingly, and in contrast to other cell types, TMEM16F did not control intracellular Ca2+ signaling and was not responsible for Ca2+-activated whole cell currents in podocytes. TMEM16F levels in podocytes were enhanced after inhibition of the endolysosomal pathway and after treatment with angiotensin II. Renal knockout of TMEM16F did not compromise renal morphology and serum electrolytes. Taken together, in contrast to other cell types, such as platelets, bone cells, and immune cells, TMEM16F shows little effect on basal properties of podocytes and does not appear to be essential for renal function.
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Affiliation(s)
- Laura K Schenk
- Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, 48149 Muenster, Germany.
| | - Jiraporn Ousingsawat
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
| | - Boris V Skryabin
- Transgenic Animal and Genetic Engineering Models (TRAM), Department of Medicine, Westfälischen, Wilhelms⁻Universität Münster, 48149 Münster, Germany.
| | - Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
| | - Hermann Pavenstädt
- Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, 48149 Muenster, Germany.
| | - Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
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47
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Pelz T, Drose DR, Fleck D, Henkel B, Ackels T, Spehr M, Neuhaus EM. An ancestral TMEM16 homolog from Dictyostelium discoideum forms a scramblase. PLoS One 2018; 13:e0191219. [PMID: 29444117 PMCID: PMC5812556 DOI: 10.1371/journal.pone.0191219] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 12/29/2017] [Indexed: 01/11/2023] Open
Abstract
TMEM16 proteins are a recently identified protein family comprising Ca2+-activated Cl- channels that generate outwardly rectifying ionic currents in response to intracellular Ca2+ elevations. Some TMEM16 family members, such as TMEM16F/ANO6 are also essential for Ca2+-dependent phospholipid scrambling. TMEM16-like genes are present in the genomes of most eukaryotic species, the function(s) of TMEM16 family members from evolutionary ancient eukaryotes is not completely clear. Here, we provide insight into the evolution of these TMEM16 proteins by similarity searches for ancestral sequences. All eukaryotic genomes contain TMEM16 homologs, but only vertebrates have the full repertoire of ten distinct subtypes. TMEM16 homologs studied so far belong to the opisthokont branch of the phylogenetic tree, which includes the animal and fungal kingdoms. An organism outside this group is Dictyostelium discoideum, a representative of the amoebozoa group that diverged from the metazoa before fungi. We here functionally investigated the TMEM16 family member from Dictyostelium discoideum. When recombinantly expressed in HEK293 cells, DdTMEM16 induces phospholipid scrambling. However, in several electrophysiological experiments we did not find evidence for a Ca2+-activated Cl- channel function of DdTMEM16.
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Affiliation(s)
- Thomas Pelz
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Daniela R. Drose
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Bastian Henkel
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tobias Ackels
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Eva M. Neuhaus
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
- * E-mail:
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48
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Schreiber R, Ousingsawat J, Wanitchakool P, Sirianant L, Benedetto R, Reiss K, Kunzelmann K. Regulation of TMEM16A/ANO1 and TMEM16F/ANO6 ion currents and phospholipid scrambling by Ca 2+ and plasma membrane lipid. J Physiol 2018; 596:217-229. [PMID: 29134661 PMCID: PMC5767690 DOI: 10.1113/jp275175] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/08/2017] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS TMEM16 proteins can operate as Ca2+ -activated Cl- channels or scramble membrane phospholipids, which are both highly relevant mechanisms during disease. Overexpression of TMEM16A and TMEM16F were found to be partially active at 37°C and at resting intracellular Ca2+ concentrations. We show that TMEM16 Cl- currents and phospholipid scrambling can be activated by modification of plasma membrane phospholipids, through reactive oxygen species and phospholipase A2. While phospholipids and Cl- ions are likely to use the same pore within TMEM16F, TMEM16A only conducts Cl- ions. Lipid regulation of TMEM16 proteins is highly relevant during inflammation and regulated cell death such as apoptosis and ferroptosis. ABSTRACT TMEM16/anoctamin (ANO) proteins form Ca2+ -activated ion channels or phospholipid scramblases. We found that both TMEM16A/ANO1 and TMEM16F/ANO6 produced Cl- currents when activated by intracellular Ca2+ , but only TMEM16F was able to expose phosphatidylserine to the outer leaflet of the plasma membrane. Mutations within TMEM16F or TMEM16A/F chimeras similarly changed Cl- currents and phospholipid scrambling, suggesting the same intramolecular pathway for Cl- and phospholipids. When overexpressed, TMEM16A and TMEM16F produced spontaneous Cl- currents at 37°C even at resting intracellular Ca2+ levels, which was abolished by inhibition of phospholipase A2 (PLA2 ). Connversely, activation of PLA2 or application of active PLA2 , as well as lipid peroxidation induced by reactive oxygen species (ROS) using staurosporine or tert-butyl hydroperoxide, enhanced ion currents by TMEM16A/F and in addition activated phospholipid scrambling by TMEM16F. Thus, TMEM16 proteins are activated by an increase in intracellular Ca2+ , or independent of intracellular Ca2+ , by modifications occurring in plasma and intracellular membrane phospholipids. These results may help to explain why regions distant to the TMEM16 pore and the Ca2+ binding sites control Cl- currents and phospholipid scrambling. Regulation of TMEM16 proteins through modification of membrane phospholipids occurs during regulated cell death such as apoptosis and ferroptosis. It contributes to inflammatory and nerve injury-induced hypersensitivity and generation of pain and therefore provides a regulatory mechanism that is particularly relevant during disease.
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Affiliation(s)
- Rainer Schreiber
- Institut für PhysiologieUniversität RegensburgUniversitätsstraße 31D‐93053RegensburgGermany
| | - Jiraporn Ousingsawat
- Institut für PhysiologieUniversität RegensburgUniversitätsstraße 31D‐93053RegensburgGermany
| | | | - Lalida Sirianant
- Institut für PhysiologieUniversität RegensburgUniversitätsstraße 31D‐93053RegensburgGermany
| | - Roberta Benedetto
- Institut für PhysiologieUniversität RegensburgUniversitätsstraße 31D‐93053RegensburgGermany
| | - Karina Reiss
- Department of DermatologyUniversity of KielSchittenhelmstrasse 7Kiel24105Germany
| | - Karl Kunzelmann
- Institut für PhysiologieUniversität RegensburgUniversitätsstraße 31D‐93053RegensburgGermany
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49
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Muratori C, Pakhomov AG, Gianulis E, Meads J, Casciola M, Mollica PA, Pakhomova ON. Activation of the phospholipid scramblase TMEM16F by nanosecond pulsed electric fields (nsPEF) facilitates its diverse cytophysiological effects. J Biol Chem 2017; 292:19381-19391. [PMID: 28982976 PMCID: PMC5702676 DOI: 10.1074/jbc.m117.803049] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/20/2017] [Indexed: 12/17/2022] Open
Abstract
Nanosecond pulsed electric fields (nsPEF) are emerging as a novel modality for cell stimulation and tissue ablation. However, the downstream protein effectors responsible for nsPEF bioeffects remain to be established. Here we demonstrate that nsPEF activate TMEM16F (or Anoctamin 6), a protein functioning as a Ca2+-dependent phospholipid scramblase and Ca2+-activated chloride channel. Using confocal microscopy and patch clamp recordings, we investigated the relevance of TMEM16F activation for several bioeffects triggered by nsPEF, including phosphatidylserine (PS) externalization, nanopore-conducted currents, membrane blebbing, and cell death. In HEK 293 cells treated with a single 300-ns pulse of 25.5 kV/cm, Tmem16f expression knockdown and TMEM16F-specific inhibition decreased nsPEF-induced PS exposure by 49 and 42%, respectively. Moreover, the Tmem16f silencing significantly decreased Ca2+-dependent chloride channel currents activated in response to the nanoporation. Tmem16f expression also affected nsPEF-induced cell blebbing, with only 20% of the silenced cells developing blebs compared with 53% of the control cells. This inhibition of cellular blebbing correlated with a 25% decrease in cytosolic free Ca2+ transient at 30 s after nanoporation. Finally, in TMEM16F-overexpressing cells, a train of 120 pulses (300 ns, 20 Hz, 6 kV/cm) decreased cell survival to 34% compared with 51% in control cells (*, p < 0.01). Taken together, these results indicate that TMEM16F activation by nanoporation mediates and enhances the diverse cellular effects of nsPEF.
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Affiliation(s)
| | | | - Elena Gianulis
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Jade Meads
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Maura Casciola
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Peter A Mollica
- the Department of Medical Diagnostics and Translational Sciences, Old Dominion University, Norfolk, Virginia 23508
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50
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Zaitseva E, Zaitsev E, Melikov K, Arakelyan A, Marin M, Villasmil R, Margolis LB, Melikyan GB, Chernomordik LV. Fusion Stage of HIV-1 Entry Depends on Virus-Induced Cell Surface Exposure of Phosphatidylserine. Cell Host Microbe 2017; 22:99-110.e7. [PMID: 28704658 PMCID: PMC5558241 DOI: 10.1016/j.chom.2017.06.012] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 03/13/2017] [Accepted: 06/22/2017] [Indexed: 12/18/2022]
Abstract
HIV-1 entry into host cells starts with interactions between the viral envelope glycoprotein (Env) and cellular CD4 receptors and coreceptors. Previous work has suggested that efficient HIV entry also depends on intracellular signaling, but this remains controversial. Here we report that formation of the pre-fusion Env-CD4-coreceptor complexes triggers non-apoptotic cell surface exposure of the membrane lipid phosphatidylserine (PS). HIV-1-induced PS redistribution depends on Ca2+ signaling triggered by Env-coreceptor interactions and involves the lipid scramblase TMEM16F. Externalized PS strongly promotes Env-mediated membrane fusion and HIV-1 infection. Blocking externalized PS or suppressing TMEM16F inhibited Env-mediated fusion. Exogenously added PS promoted fusion, with fusion dependence on PS being especially strong for cells with low surface density of coreceptors. These findings suggest that cell-surface PS acts as an important cofactor that promotes the fusogenic restructuring of pre-fusion complexes and likely focuses the infection on cells conducive to PS signaling.
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Affiliation(s)
- Elena Zaitseva
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Eugene Zaitsev
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Kamran Melikov
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anush Arakelyan
- Section on Intercellular Interactions, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Mariana Marin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Rafael Villasmil
- Flow Cytometry Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leonid B Margolis
- Section on Intercellular Interactions, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Gregory B Melikyan
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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