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Yuan L, Tang Y, Yin L, Lin X, Luo Z, Wang S, Li J, Liang P, Jiang B. The role of Transmembrane Protein 16A (TMEM16A) in pulmonary hypertension. Cardiovasc Pathol 2023; 65:107525. [PMID: 36781068 DOI: 10.1016/j.carpath.2023.107525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/13/2023] Open
Abstract
Transmembrane protein 16A (TMEM16A), a member of the TMEM16 family, is the molecular basis of Ca2+-activated chloride channels (CaCCs) and is involved in a variety of physiological and pathological processes. Previous studies have focused more on respiratory-related diseases and tumors. However, recent studies have identified an important role for TMEM16A in cardiovascular diseases, especially in pulmonary hypertension. TMEM16A is expressed in both pulmonary artery smooth muscle cells and pulmonary artery endothelial cells and is involved in the development of pulmonary hypertension. This paper presents the structure and function of TMEM16A, the pathogenesis of pulmonary hypertension, and highlights the role and mechanism of TMEM16A in pulmonary hypertension, summarizing the controversies in this field and taking into account hypertension and portal hypertension, which have similar pathogenesis. It is hoped that the unique role of TMEM16A in pulmonary hypertension will be illustrated and provide ideas for research in this area.
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Affiliation(s)
- Ludong Yuan
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Yuting Tang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Leijing Yin
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Xiaofang Lin
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Zhengyang Luo
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Shuxin Wang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Jing Li
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Pengfei Liang
- Department of Burns and Plastic Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bimei Jiang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China.
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Polymodal Control of TMEM16x Channels and Scramblases. Int J Mol Sci 2022; 23:ijms23031580. [PMID: 35163502 PMCID: PMC8835819 DOI: 10.3390/ijms23031580] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
The TMEM16A/anoctamin-1 calcium-activated chloride channel (CaCC) contributes to a range of vital functions, such as the control of vascular tone and epithelial ion transport. The channel is a founding member of a family of 10 proteins (TMEM16x) with varied functions; some members (i.e., TMEM16A and TMEM16B) serve as CaCCs, while others are lipid scramblases, combine channel and scramblase function, or perform additional cellular roles. TMEM16x proteins are typically activated by agonist-induced Ca2+ release evoked by Gq-protein-coupled receptor (GqPCR) activation; thus, TMEM16x proteins link Ca2+-signalling with cell electrical activity and/or lipid transport. Recent studies demonstrate that a range of other cellular factors—including plasmalemmal lipids, pH, hypoxia, ATP and auxiliary proteins—also control the activity of the TMEM16A channel and its paralogues, suggesting that the TMEM16x proteins are effectively polymodal sensors of cellular homeostasis. Here, we review the molecular pathophysiology, structural biology, and mechanisms of regulation of TMEM16x proteins by multiple cellular factors.
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Ji W, Shi D, Shi S, Yang X, Chen Y, An H, Pang C. TMEM16A protein: calcium binding site and its activation mechanism. Protein Pept Lett 2021; 28:1338-1348. [PMID: 34749600 DOI: 10.2174/0929866528666211105112131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/08/2021] [Accepted: 09/18/2021] [Indexed: 11/22/2022]
Abstract
TMEM16A mediates calcium-activated transmembrane flow of chloride ion and a variety of physiological functions. The binding of cytoplasmic calcium ions of TMEM16A and the consequent conformational changes of it are the key issues to explore the relationship between its structure and function. In recent years, researchers have explored this issue through electrophysiological experiment, structure resolving, molecular dynamic simulation and other methods. The structures of TMEM16 family members resolved by cryo-Electron microscopy (cryo-EM) and X-ray crystallization provide the primarily basis for the investigation of the molecular mechanism of TMEM16A. However, the binding and activation mechanism of calcium ions in TMEM16A are still unclear and controversial. This review discusses four Ca2+ sensing sites of TMEM16A and analyze activation properties of TMEM16A by them, which will help to understand the structure-function relationship of TMEM16A and throw light on the molecular design targeting TMEM16A channel.
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Affiliation(s)
- Wanying Ji
- Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin 300401. China
| | - Donghong Shi
- Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin 300401. China
| | - Sai Shi
- Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin 300401. China
| | - Xiao Yang
- Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin 300401. China
| | - Yafei Chen
- Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin 300401. China
| | - Hailong An
- Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin 300401. China
| | - Chunli Pang
- Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin 300401. China
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Luo S, Wang H, Bai L, Chen Y, Chen S, Gao K, Wang H, Wu S, Song H, Ma K, Liu M, Yao F, Fang Y, Xiao Q. Activation of TMEM16A Ca 2+-activated Cl - channels by ROCK1/moesin promotes breast cancer metastasis. J Adv Res 2021; 33:253-264. [PMID: 34603794 PMCID: PMC8463928 DOI: 10.1016/j.jare.2021.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/28/2021] [Accepted: 03/13/2021] [Indexed: 12/01/2022] Open
Abstract
Introduction Transmembrane protein 16A (TMEM16A) is a Ca2+-activated chloride channel that plays a role in cancer cell proliferation, migration, invasion, and metastasis. However, whether TMEM16A contributes to breast cancer metastasis remains unknown. Objective In this study, we investigated whether TMEM16A channel activation by ROCK1/moesin promotes breast cancer metastasis. Methods Wound healing assays and transwell migration and invasion assays were performed to study the migration and invasion of MCF-7 and T47D breast cancer cells. Western blotting was performed to evaluate the protein expression, and whole-cell patch clamp recordings were used to record TMEM16A Cl− currents. A mouse model of breast cancer lung metastasis was generated by injecting MCF-7 cells via the tail vein. Metastatic nodules in the lung were assessed by hematoxylin and eosin staining. Lymph node metastasis, overall survival, and metastasis-free survival of breast cancer patients were assessed using immunohistochemistry and The Cancer Genome Atlas dataset. Results TMEM16A activation promoted breast cancer cell migration and invasion in vitro as well as breast cancer metastasis in mice. Patients with breast cancer who had higher TMEM16A levels showed greater lymph node metastasis and shorter survival. Mechanistically, TMEM16A promoted migration and invasion by activating EGFR/STAT3/ROCK1 signaling, and the role of the TMEM16A channel activity was important in this respect. ROCK1 activation by RhoA enhanced the TMEM16A channel activity via the phosphorylation of moesin at T558. The cooperative action of TMEM16A and ROCK1 was supported through clinical findings indicating that breast cancer patients with high levels of TMEM16A/ROCK1 expression showed greater lymph node metastasis and poor survival. Conclusion Our findings revealed a novel mechanism underlying TMEM16A-mediated breast cancer metastasis, in which ROCK1 increased TMEM16A channel activity via moesin phosphorylation and the increase in TMEM16A channel activities promoted cell migration and invasion. TMEM16A inhibition may be a novel strategy for treating breast cancer metastasis.
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Key Words
- Cl− channel
- EGFR, epidermal growth factor receptor
- ER, estrogen receptor
- FBS, fetal bovine serum
- H&E, hematoxylin and eosin
- HNSCC, head and neck squamous cell carcinoma
- IHC, immunohistochemical
- MFS, metastasis-free survival
- Metastasis
- Moesin
- OS, overall survival
- PR, progesterone receptor
- ROCK1
- ROCK1, Rho-associated, coiled-coil containing protein kinase 1
- STAT3, signal transducers and activators of transcription 3
- TCGA, The Cancer Genome Atlas
- TMEM16A
- shRNAs, small hairpin RNAs
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Affiliation(s)
- Shuya Luo
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Hui Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Lichuan Bai
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Yiwen Chen
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Si Chen
- Department of Microbial and Biochemical Pharmacy, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Kuan Gao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Huijie Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Shuwei Wu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Hanbin Song
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Ke Ma
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Mei Liu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Fan Yao
- Department of Breast Surgery and Surgical Oncology, Research Unit of General Surgery, The First Affiliated Hospital of China Medical University, Shenyang 110001, China
| | - Yue Fang
- Department of Microbial and Biochemical Pharmacy, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
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Wang T, Wang H, Yang F, Gao K, Luo S, Bai L, Ma K, Liu M, Wu S, Wang H, Chen Z, Xiao Q. Honokiol inhibits proliferation of colorectal cancer cells by targeting anoctamin 1/TMEM16A Ca 2+ -activated Cl - channels. Br J Pharmacol 2021; 178:4137-4154. [PMID: 34192810 DOI: 10.1111/bph.15606] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 05/25/2021] [Accepted: 06/06/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Ca2+ -activated Cl- channels (Ano1 channels) contribute to the pathogenesis of colorectal cancer. Honokiol is known to inhibit cell proliferation and tumour growth in colorectal cancer. However, the molecular target of honokiol remains unclear. This study aimed to investigate whether honokiol inhibited cell proliferation of colorectal cancer by targeting Ano1 channels. EXPERIMENTAL APPROACH Patch-clamp techniques were performed to study the effect of honokiol on Ca2+ -activated Cl- currents in HEK293 cells overexpressing Ano1- or Ano2-containing plasmids or in human colorectal carcinoma SW620 cells. Site-directed mutagenesis was used to identify the critical residues for honokiol-induced Ano1 inhibition. Proliferation of SW620 cells or human intestinal epithelial NCM460 cells by CCK-8 assays. KEY RESULTS Honokiol blocked Ano1 currents in Ano1-overexpressing HEK293 cells and SW620 cells. Honokiol more potently inhibited Ano1 currents than Ano2 currents. Three amino acids (R429, K430 and N435) were critical for honokiol-induced Ano1 inhibition. The R429A/K430L/N435G mutation reduced the sensitivity of Ano1 to honokiol. Honokiol inhibited SW620 cell proliferation, and this effect was reduced by Ano1-shRNAs. Furthermore, Ano1 overexpression promoted proliferation in NCM460 cells with low Ano1 endogenous expression and resulted in an increased sensitivity to honokiol. Overexpression of the R429A/K430L/N435G mutation reduced WT Ano1-induced increase in the sensitivity of NCM460 cells to honokiol. CONCLUSION AND IMPLICATIONS We identified a new anticancer mechanism of honokiol, through the inhibition of cell proliferation, by targeting Ano1 Ca2+ -activated Cl- channels.
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Affiliation(s)
- Tianyu Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Hui Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Fan Yang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Kuan Gao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Shuya Luo
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Lichuan Bai
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Ke Ma
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Mei Liu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Shuwei Wu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Huijie Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
| | - Zaixing Chen
- Pharmaceutical Teaching and Experimental Center, School of Pharmacy, China Medical University, Shenyang, China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, China
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Wang H, Wang T, Zhang Z, Fan Y, Zhang L, Gao K, Luo S, Xiao Q, Sun C. Simvastatin inhibits oral squamous cell carcinoma by targeting TMEM16A Ca 2+-activated chloride channel. J Cancer Res Clin Oncol 2021; 147:1699-1711. [PMID: 33755783 DOI: 10.1007/s00432-021-03575-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/18/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE Ca2+-activated chloride channel TMEM16A has been found to be overexpressed in many cancers including head and neck squamous cell carcinoma (HNSCC). Nevertheless, the role of TMEM16A in oral squamous cell carcinoma (OSCC) remains unclear. Although simvastatin is known to produce anti-tumor effect, the mechanisms by which simvastatin inhibits cancer remain unclear. METHODS In this study, we explored the role of TMEM16A expression in human OSCC tissues using both TCGA dataset and immunohistochemistry. CCK-8 assay was applied to evaluate cell proliferation. Patch clamp technique was applied to record TMEM16A Cl- currents. RESULTS We found that high TMEM16A expression is related with large tumor size, lymph node metastasis, and poor clinical outcome in patients with OSCC. In addition, TMEM16A overexpression could promote cell proliferation, and inhibition of TMEM16A channel activities could suppress cell proliferation in OSCC cells. Furthermore, simvastatin could suppress TMEM16A channel activities, and inhibited cell proliferation in OSCC cells via TMEM16A. CONCLUSION Our findings identify a novel anti-tumor mechanism of simvastatin by targeting TMEM16A. Simvastatin may represent an innovative strategy for treating OSCC with high TMEM16A expression.
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Affiliation(s)
- Hechen Wang
- Liaoning Provincial Key Laboratory of Oral Diseases, Department of Oromaxillofacial-Head and Neck Surgery, School and Hospital of Stomatology, China Medical University, 117 Nanjing Bei Jie, Heping District, Shenyang,, 110002, Liaoning, China.,Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, China
| | - Tianyu Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, China
| | - Zeying Zhang
- Liaoning Provincial Key Laboratory of Oral Diseases, Department of Oromaxillofacial-Head and Neck Surgery, School and Hospital of Stomatology, China Medical University, 117 Nanjing Bei Jie, Heping District, Shenyang,, 110002, Liaoning, China
| | - Yu Fan
- Liaoning Provincial Key Laboratory of Oral Diseases, Department of Pathology, School and Hospital of Stomatology, China Medical University, Shenyang, China
| | - Lan Zhang
- Liaoning Provincial Key Laboratory of Oral Diseases, Hospital Infection Management Office, School and Hospital of Stomatology, China Medical University, Shenyang, China
| | - Kuan Gao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, China
| | - Shuya Luo
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, China.
| | - Changfu Sun
- Liaoning Provincial Key Laboratory of Oral Diseases, Department of Oromaxillofacial-Head and Neck Surgery, School and Hospital of Stomatology, China Medical University, 117 Nanjing Bei Jie, Heping District, Shenyang,, 110002, Liaoning, China.
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The Groovy TMEM16 Family: Molecular Mechanisms of Lipid Scrambling and Ion Conduction. J Mol Biol 2021; 433:166941. [PMID: 33741412 DOI: 10.1016/j.jmb.2021.166941] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/09/2021] [Accepted: 03/09/2021] [Indexed: 12/28/2022]
Abstract
The TMEM16 family of membrane proteins displays a remarkable functional dichotomy - while some family members function as Ca2+-activated anion channels, the majority of characterized TMEM16 homologs are Ca2+-activated lipid scramblases, which catalyze the exchange of phospholipids between the two membrane leaflets. Furthermore, some TMEM16 scramblases can also function as channels. Due to their involvement in important physiological processes, the family has been actively studied ever since their molecular identity was unraveled. In this review, we will summarize the recent advances in the field and how they influenced our view of TMEM16 family function and evolution. Structural, functional and computational studies reveal how relatively small rearrangements in the permeation pathway are responsible for the observed functional duality: while TMEM16 scramblases can adopt both ion- and lipid conductive conformations, TMEM16 channels can only populate the former. Recent data further provides the molecular details of a stepwise activation mechanism, which is initiated by Ca2+ binding and modulated by various cellular factors, including lipids. TMEM16 function and the surrounding membrane properties are inextricably intertwined, with the protein inducing bilayer deformations associated with scrambling, while the surrounding lipids modulate TMEM16 conformation and activity.
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Shin DH, Kim M, Kim Y, Jun I, Jung J, Nam JH, Cheng MH, Lee MG. Bicarbonate permeation through anion channels: its role in health and disease. Pflugers Arch 2020; 472:1003-1018. [PMID: 32621085 DOI: 10.1007/s00424-020-02425-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/19/2020] [Accepted: 06/26/2020] [Indexed: 12/31/2022]
Abstract
Many anion channels, frequently referred as Cl- channels, are permeable to different anions in addition to Cl-. As the second-most abundant anion in the human body, HCO3- permeation via anion channels has many important physiological roles. In addition to its classical role as an intracellular pH regulator, HCO3- also controls the activity and stability of dissolved proteins in bodily fluids such as saliva, pancreatic juice, intestinal fluid, and airway surface liquid. Moreover, HCO3- permeation through these channels affects membrane potentials that are the driving forces for transmembrane transport of solutes and water in epithelia and affect neuronal excitability in nervous tissue. Consequently, aberrant HCO3- transport via anion channels causes a number of human diseases in respiratory, gastrointestinal, genitourinary, and neuronal systems. Notably, recent studies have shown that the HCO3- permeabilities of several anion channels are not fixed and can be altered by cellular stimuli, findings which may have both physiological and pathophysiological significance. In this review, we summarize recent progress in understanding the molecular mechanisms and the physiological roles of HCO3- permeation through anion channels. We hope that the present discussions can stimulate further research into this very important topic, which will provide the basis for human disorders associated with aberrant HCO3- transport.
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Affiliation(s)
- Dong Hoon Shin
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Minjae Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Yonjung Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Ikhyun Jun
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Jinsei Jung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Kyungju, 780-714, Republic of Korea
| | - Mary Hongying Cheng
- Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea.
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Wang Q, Bai L, Luo S, Wang T, Yang F, Xia J, Wang H, Ma K, Liu M, Wu S, Wang H, Guo S, Sun X, Xiao Q. TMEM16A Ca 2+-activated Cl - channel inhibition ameliorates acute pancreatitis via the IP 3R/Ca 2+/NFκB/IL-6 signaling pathway. J Adv Res 2020; 23:25-35. [PMID: 32071789 PMCID: PMC7016042 DOI: 10.1016/j.jare.2020.01.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/14/2020] [Accepted: 01/18/2020] [Indexed: 02/08/2023] Open
Abstract
TMEM16A Ca2+-activated Cl- channels are expressed in pancreatic acinar cells and participate in inflammation-associated diseases. Whether TMEM16A contributes to the pathogenesis of acute pancreatitis (AP) remains unknown. Here, we found that increased TMEM16A expression in the pancreatic tissue was correlated with the interleukin-6 (IL-6) level in the pancreatic tissue and in the serum of a cerulein-induced AP mouse model. IL-6 treatment promoted TMEM16A expression in AR42J pancreatic acinar cells via the IL-6 receptor (IL-6R)/signal transducers and activators of transcription 3 (STAT3) signaling pathway. In addition, TMEM16A was co-immunoprecipitated with the inositol 1,4,5-trisphosphate receptor (IP3R) and was activated by IP3R-mediated Ca2+ release. TMEM16A inhibition reduced the IP3R-mediated Ca2+ release induced by cerulein. Furthermore, TMEM16A overexpression activated nuclear factor-κB (NFκB) and increased IL-6 release by increasing intracellular Ca2+. TMEM16A knockdown by shRNAs reduced the cerulein-induced NFκB activation by Ca2+. TMEM16A inhibitors inhibited NFκB activation by decreasing channel activity and reducing TMEM16A protein levels in AR42J cells, and it ameliorated pancreatic damage in cerulein-induced AP mice. This study identifies a novel mechanism underlying the pathogenesis of AP by which IL-6 promotes TMEM16A expression via IL-6R/STAT3 signaling activation, and TMEM16A overexpression increases IL-6 secretion via IP3R/Ca2+/NFκB signaling activation in pancreatic acinar cells. TMEM16A inhibition may be a new potential strategy for treating AP.
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Key Words
- AP, acute pancreatitis
- Acute pancreatitis
- BAPTA-AM, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid-acetyloxymethyl ester
- CCK, cholesystokinin
- CFBE, cystic fibrosis bronchial epithelial
- CaCCinh-A01, Ca2+-activated Cl− channel inhibitor-A01
- EDTA, ethylenediaminetetraacetic acid
- EGF, epidermal growth factor
- EGFP, green fluorescent protein
- EGFR, epidermal growth factor receptor
- EGTA, ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid
- ELISA, enzyme-linked immunosorbent assay
- ER, endoplasmic reticulum
- FBS, fetal bovine serum
- HEPES, N-2-hydroxyethil-piperazine-N'-2-ethanesulfonic acid
- IL-6, interleukin 6
- IL-6R, interleukin 6 receptor
- IP3R, inositol 1,4,5-trisphosphate receptor
- Inositol 1,4,5-trisphosphate receptor
- Interleukin-6
- NFκB
- NFκB, nuclear factor-κB
- NMDG, N-methyl-D-glucamine
- NP-40, Nonidet P-40
- PACs, pancreatic acinar cells
- RIPA, radio immunoprecipitation assay
- SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis
- STAT3, signal transducers and activators of transcription 3
- T16Ainh-A01, TMEM16A inhibitor-A01
- TMEM16A
- Tris, tris(hydroxymethyl)aminomethane
- WT, wild type
- shRNAs, short hairpin RNAs
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Affiliation(s)
- Qinghua Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China.,Department of Experimental Center, The Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, Shenyang 110032, China
| | - Lichuan Bai
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Shuya Luo
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Tianyu Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Fan Yang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Jialin Xia
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Hui Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Ke Ma
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Mei Liu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Shuwei Wu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Huijie Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Shibin Guo
- Department of Gastroenterological Endoscopy, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, China
| | - Xiaohong Sun
- Department of Neurology, The Fourth Affiliated Hospital of China Medical University, Shenyang 110032, China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
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10
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Tak MH, Jang Y, Son WS, Yang YD, Oh U. EF-hand like Region in the N-terminus of Anoctamin 1 Modulates Channel Activity by Ca 2+ and Voltage. Exp Neurobiol 2019; 28:658-669. [PMID: 31902154 PMCID: PMC6946113 DOI: 10.5607/en.2019.28.6.658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 11/30/2019] [Indexed: 11/28/2022] Open
Abstract
Anoctamin1 (ANO1) also known as TMEM16A is a transmembrane protein that functions as a Ca2+ activated chloride channel. Recently, the structure determination of a fungal Nectria haematococca TMEM16 (nhTMEM16) scramblase by X-ray crystallography and a mouse ANO1 by cryo-electron microscopy has provided the insight in molecular architecture underlying phospholipid scrambling and Ca2+ binding. Because the Ca2+ binding motif is embedded inside channel protein according to defined structure, it is still unclear how intracellular Ca2+ moves to its deep binding pocket effectively. Here we show that EF-hand like region containing multiple acidic amino acids at the N-terminus of ANO1 is a putative site regulating the activity of ANO1 by Ca2+ and voltage. The EF-hand like region of ANO1 is highly homologous to the canonical EF hand loop in calmodulin that contains acidic residues in key Ca2+-coordinating positions in the canonical EF hand. Indeed, deletion and Ala-substituted mutation of this region resulted in a significant reduction in the response to Ca2+ and changes in its key biophysical properties evoked by voltage pulses. Furthermore, only ANO1 and ANO2, and not the other TMEM16 isoforms, contain the EF-hand like region and are activated by Ca2+. Moreover, the molecular modeling analysis supports that EF-hand like region could play a key role during Ca2+ transfer. Therefore, these findings suggest that EF-hand like region in ANO1 coordinates with Ca2+ and modulate the activation by Ca2+ and voltage.
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Affiliation(s)
- Min Ho Tak
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 08826, Korea
| | - Yongwoo Jang
- Department of Biomedical Engineering, Hanyang University, Seoul 04763, Korea
| | - Woo Sung Son
- College of Pharmacy, CHA University, Seongnam 13488, Korea
| | - Young Duk Yang
- College of Pharmacy, CHA University, Seongnam 13488, Korea
| | - Uhtaek Oh
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 08826, Korea.,Sensory Research Center, Brain Science Institute, Korea Institute of Science & Technology (KIST), Seoul 02792, Korea
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11
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Ji Q, Guo S, Wang X, Pang C, Zhan Y, Chen Y, An H. Recent advances in TMEM16A: Structure, function, and disease. J Cell Physiol 2018; 234:7856-7873. [PMID: 30515811 DOI: 10.1002/jcp.27865] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/13/2018] [Indexed: 12/13/2022]
Abstract
TMEM16A (also known as anoctamin 1, ANO1) is the molecular basis of the calcium-activated chloride channels, with ten transmembrane segments. Recently, atomic structures of the transmembrane domains of mouse TMEM16A (mTMEM16A) were determined by single-particle electron cryomicroscopy. This gives us a solid ground to discuss the electrophysiological properties and functions of TMEM16A. TMEM16A is reported to be dually regulated by Ca2+ and voltage. In addition, the dysfunction of TMEM16A has been found to be involved in many diseases including cystic fibrosis, various cancers, hypertension, and gastrointestinal motility disorders. TMEM16A is overexpressed in many cancers, including gastrointestinal stromal tumors, gastric cancer, head and neck squamous cell carcinoma (HNSCC), colon cancer, pancreatic ductal adenocarcinoma, and esophageal cancer. Furthermore, overexpression of TMEM16A is related to the occurrence, proliferation, and migration of tumor cells. To date, several studies have shown that many natural compounds and synthetic compounds have regulatory effects on TMEM16A. These small molecule compounds might be novel drugs for the treatment of diseases caused by TMEM16A dysfunction in the future. In addition, recent studies have shown that TMEM16A plays different roles in different diseases through different signal transduction pathways. This review discusses the topology, electrophysiological properties, modulators and functions of TMEM16A in mediates nociception, gastrointestinal dysfunction, hypertension, and cancer and focuses on multiple regulatory mechanisms regarding TMEM16A.
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Affiliation(s)
- Qiushuang Ji
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Shuai Guo
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Xuzhao Wang
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Chunli Pang
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Yong Zhan
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Yafei Chen
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Hailong An
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
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12
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Medrano-Soto A, Moreno-Hagelsieb G, McLaughlin D, Ye ZS, Hendargo KJ, Saier MH. Bioinformatic characterization of the Anoctamin Superfamily of Ca2+-activated ion channels and lipid scramblases. PLoS One 2018; 13:e0192851. [PMID: 29579047 PMCID: PMC5868767 DOI: 10.1371/journal.pone.0192851] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/31/2018] [Indexed: 01/01/2023] Open
Abstract
Our laboratory has developed bioinformatic strategies for identifying distant phylogenetic relationships and characterizing families and superfamilies of transport proteins. Results using these tools suggest that the Anoctamin Superfamily of cation and anion channels, as well as lipid scramblases, includes three functionally characterized families: the Anoctamin (ANO), Transmembrane Channel (TMC) and Ca2+-permeable Stress-gated Cation Channel (CSC) families; as well as four families of functionally uncharacterized proteins, which we refer to as the Anoctamin-like (ANO-L), Transmembrane Channel-like (TMC-L), and CSC-like (CSC-L1 and CSC-L2) families. We have constructed protein clusters and trees showing the relative relationships among the seven families. Topological analyses suggest that the members of these families have essentially the same topologies. Comparative examination of these homologous families provides insight into possible mechanisms of action, indicates the currently recognized organismal distributions of these proteins, and suggests drug design potential for the disease-related channel proteins.
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Affiliation(s)
- Arturo Medrano-Soto
- Department of Molecular Biology, University of California at San Diego, La Jolla, California, United States of America
| | | | - Daniel McLaughlin
- Department of Molecular Biology, University of California at San Diego, La Jolla, California, United States of America
| | - Zachary S. Ye
- Department of Molecular Biology, University of California at San Diego, La Jolla, California, United States of America
| | - Kevin J. Hendargo
- Department of Molecular Biology, University of California at San Diego, La Jolla, California, United States of America
| | - Milton H. Saier
- Department of Molecular Biology, University of California at San Diego, La Jolla, California, United States of America
- * E-mail:
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13
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Strege PR, Gibbons SJ, Mazzone A, Bernard CE, Beyder A, Farrugia G. EAVK segment "c" sequence confers Ca 2+-dependent changes to the kinetics of full-length human Ano1. Am J Physiol Gastrointest Liver Physiol 2017; 312:G572-G579. [PMID: 28336549 PMCID: PMC5495914 DOI: 10.1152/ajpgi.00429.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/07/2017] [Accepted: 03/15/2017] [Indexed: 01/31/2023]
Abstract
Anoctamin1 (Ano1 and TMEM16A) is a calcium-activated chloride channel specifically expressed in the interstitial cells of Cajal (ICC) of the gastrointestinal tract muscularis propria. Ano1 is necessary for normal electrical slow waves and ICC proliferation. The full-length human Ano1 sequence includes an additional exon, exon "0," at the NH2 terminus. Ano1 with exon 0 [Ano1(0)] had a lower EC50 for intracellular calcium ([Ca2+]i) and faster chloride current (ICl) kinetics. The Ano1 alternative splice variant with segment "c" encoding exon 13 expresses on the first intracellular loop four additional amino acid residues, EAVK, which alter ICl at low [Ca2+]i Exon 13 is expressed in 75-100% of Ano1 transcripts in most human tissues but only 25% in the human stomach. Our aim was to determine the effect of EAVK deletion on Ano1(0)ICl parameters. By voltage-clamp electrophysiology, we examined ICl in HEK293 cells transiently expressing Ano1(0) with or without the EAVK sequence [Ano1(0)ΔEAVK]. The EC50 values of activating and deactivating ICl for [Ca2+]i were 438 ± 7 and 493 ± 9 nM for Ano1(0) but higher for Ano1(0)ΔEAVK at 746 ± 47 and 761 ± 26 nM, respectively. Meanwhile, the EC50 values for the ratio of instantaneous to steady-state ICl were not different between variants. Congruently, the time constant of activation was slower for Ano1(0)ΔEAVK than Ano1(0) currents at intermediate [Ca2+]i These results suggest that EAVK decreases the calcium sensitivity of Ano1(0) current activation and deactivation by slowing activation kinetics. Differential expression of EAVK in the human stomach may function as a switch to increase sensitivity to [Ca2+]i via faster gating of Ano1.NEW & NOTEWORTHY Calcium-activated chloride channel anoctamin1 (Ano1) is necessary for normal slow waves in the gastrointestinal interstitial cells of Cajal. Exon 0 encodes the NH2 terminus of full-length human Ano1 [Ano1(0)], while exon 13 encodes residues EAVK on its first intracellular loop. Splice variants lack EAVK more often in the stomach than other tissues. Ano1(0) without EAVK [Ano1(0)ΔEAVK] has reduced sensitivity for intracellular calcium, attributable to slower kinetics. Differential expression of EAVK may function as a calcium-sensitive switch in the human stomach.
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14
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Ma K, Wang H, Yu J, Wei M, Xiao Q. New Insights on the Regulation of Ca 2+ -Activated Chloride Channel TMEM16A. J Cell Physiol 2016; 232:707-716. [PMID: 27682822 DOI: 10.1002/jcp.25621] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 09/27/2016] [Indexed: 12/16/2022]
Abstract
TMEM16A, also known as anoctamin 1, is a recently identified Ca2+ -activated chloride channel and the first member of a 10-member TMEM16 family. TMEM16A dysfunction is implicated in many diseases such as cancer, hypertension, and cystic fibrosis. TMEM16A channels are well known to be dually regulated by voltage and Ca2+ . In addition, recent studies have revealed that TMEM16A channels are regulated by many molecules such as calmodulin, protons, cholesterol, and phosphoinositides, and a diverse range of stimuli such as thermal and mechanical stimuli. A better understanding of the regulatory mechanisms of TMEM16A is important to understand its physiological and pathological role. Recently, the crystal structure of a TMEM16 family member from the fungus Nectria haematococcaten (nhTMEM16) is discovered, and provides valuable information for studying the structure and function of TMEM16A. In this review, we discuss the structure and function of TMEM16A channels based on the crystal structure of nhTMEM16A and focus on the regulatory mechanisms of TMEM16A channels. J. Cell. Physiol. 232: 707-716, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ke Ma
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, P. R. China
| | - Hui Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, P. R. China
| | - Jiankun Yu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, P. R. China
| | - Minjie Wei
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, P. R. China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang, P. R. China
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15
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Ishihara K, Suzuki J, Nagata S. Role of Ca(2+) in the Stability and Function of TMEM16F and 16K. Biochemistry 2016; 55:3180-8. [PMID: 27227820 DOI: 10.1021/acs.biochem.6b00176] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
There are 10 transmembrane protein (TMEM) 16-family proteins in humans and mice. Among them, TMEM16F acts as a Ca(2+)-dependent phospholipid scramblase at the plasma membrane. However, how Ca(2+) activates TMEM16F's phospholipid-scramblase activity has not been elucidated. Here we found that in the presence of Ca(2+), TMEM16K (whose function is unknown) directly binds Ca(2+) to form a stable complex that can be detected by blue-native polyacrylamide gel electrophoresis. In the absence of Ca(2+), TMEM16K and TMEM16F aggregated, suggesting that their structure is stabilized by Ca(2+). Comprehensive mutagenesis of acidic residues in TMEM16K's cytoplasmic and transmembrane regions identified five residues that are critical for binding Ca(2+). These residues were well conserved between TMEM16F and 16K, and point mutations of these residues in TMEM16F reduced its ability to support Ca(2+)-dependent phospholipid scrambling. Our results suggest that Ca(2+) binds TMEM16F directly and induces conformational changes that support its stability and function.
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Affiliation(s)
- Kenji Ishihara
- Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University , 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Jun Suzuki
- Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University , 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Shigekazu Nagata
- Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University , 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
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16
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Two Ca(2+)-Binding Sites Cooperatively Couple Together in TMEM16A Channel. J Membr Biol 2015; 249:57-63. [PMID: 26708576 DOI: 10.1007/s00232-015-9846-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/18/2015] [Indexed: 02/07/2023]
Abstract
TMEM16A is the molecular basis of calcium-activated chloride channels and shows Ca(2+)-dependent gating. It is critical to understand how the Ca(2+) sensors dynamically control the gate of TMEM16A. However, the detailed mechanism by which the calcium ions bind and open the channel is still obscure. In this study, the authors confirmed that there are two Ca(2+) sensors which cooperatively couple together in TMEM16A. Our data show that mutations at both Ca(2+)-sensitive domains, E447Y and E702Q-E705Q, weaken the Ca(2+) affinity for TMEM16A channel. The EC50 for WT, E447Y, and E702Q-E705Q are 0.53 ± 0.11, 14.5 ± 0.3, and 26.5 ± 3.6 μM, respectively. The triple mutation, including both of the Ca(2+) sensors, E447Y-E702Q-E705Q, with EC50 as 55.6 ± 5.1 μM, results in much further right-shifted dose response curve than the single sensor's mutations (E447Y, E702Q-E705Q) do, which indicates that there is a cooperation between the two Ca(2+)-sensitive domains. We also found that the divalent cations, both Ca(2+) and Sr(2+), share common mechanism of gating the TMEM16A.
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17
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Cruz-Rangel S, De Jesús-Pérez JJ, Contreras-Vite JA, Pérez-Cornejo P, Hartzell HC, Arreola J. Gating modes of calcium-activated chloride channels TMEM16A and TMEM16B. J Physiol 2015; 593:5283-98. [PMID: 26728431 DOI: 10.1113/jp271256] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/12/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Calcium-activated chloride channels TMEM16A and TMEM16B support important physiological processes such as fast block of polyspermy, fluid secretion, control of blood pressure and sensory transduction. Given the physiological importance of TMEM16 channels, it is important to study how incoming stimuli activate these channels. Here we study how channels open and close and how the process of gating is regulated. We show that TMEM16A and TMEM16B display fast and slow gating. These gating modes are regulated by voltage and external chloride. Dual gating explains the complex time course of the anion current. Residues within the first intracellular loop of the channel influence the slow gating mode. Dual gating is an intrinsic property observed in endogenous calcium-activated chloride channels and could be relevant to physiological processes that require sustained chloride ion movement. ABSTRACT TMEM16A and TMEM16B are molecular components of the physiologically relevant calcium-activated chloride channels (CaCCs) present in many tissues. Their gating is dictated by membrane voltage (Vm ), intracellular calcium concentrations ([Ca(2+) ]i ) and external permeant anions. As a consequence, the chloride current (ICl ) kinetics is complex. For example, TMEM16A ICl activates slowly with a non-mono-exponential time course while TMEM16B ICl activates rapidly following a mono-exponential behaviour. To understand the underlying mechanism responsible for the complex activation kinetics, we recorded ICl from HEK-293 cells transiently transfected with either TMEM16A or TMEM16B as well as from mouse parotid acinar cells. Two distinct Vm -dependent gating modes were uncovered: a fast-mode on the millisecond time scale followed by a slow mode on the second time scale. Using long (20 s) depolarizing pulses both gating modes were activated, and a slowly rising ICl was recorded in whole-cell and inside-out patches. The amplitude of ICl at the end of the long pulse nearly doubled and was blocked by 100 μm tannic acid. The slow gating mode was strongly reduced by decreasing the [Cl(-) ]o from 140 to 30 mm and by altering the sequence of the first intracellular loop. Mutating 480 RSQ482 to AVK in the first intracellular loop of TMEM16B nearly abolished slow gating, but, mutating 448 AVK451 to RSQ in TMEM16A has little effect. Deleting 448 EAVK451 residues in TMEM16A reduced slow gating. We conclude that TMEM16 CaCCs have intrinsic Vm - and Cl(-) -sensitive dual gating that elicits complex ICl kinetics.
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Affiliation(s)
- Silvia Cruz-Rangel
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP, 78290, México
| | - José J De Jesús-Pérez
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP, 78290, México
| | - Juan A Contreras-Vite
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP, 78290, México
| | - Patricia Pérez-Cornejo
- Department of Physiology, Universidad Autónoma de San Luis Potosí School of Medicine, Ave. V. Carranza 2405, San Luis Potosí, SLP, 78290, Mexico
| | - H Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Jorge Arreola
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP, 78290, México
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18
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Strege PR, Bernard CE, Mazzone A, Linden DR, Beyder A, Gibbons SJ, Farrugia G. A novel exon in the human Ca2+-activated Cl- channel Ano1 imparts greater sensitivity to intracellular Ca2. Am J Physiol Gastrointest Liver Physiol 2015; 309:G743-9. [PMID: 26359375 PMCID: PMC4628966 DOI: 10.1152/ajpgi.00074.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 09/06/2015] [Indexed: 01/31/2023]
Abstract
Anoctamin 1 (Ano1; TMEM16A) is a Ca(2+)-activated Cl(-) channel (CACC) expressed in interstitial cells of Cajal. The mechanisms by which Ca(2+) regulates Ano1 are incompletely understood. In the gastrointestinal tract, Ano1 is required for normal slow wave activity and is involved in regulating cell proliferation. Splice variants of Ano1 have varying electrophysiological properties and altered expression in disease states. Recently, we identified a transcript for human Ano1 containing a novel exon-"exon 0" upstream of and in frame with exon 1. The electrophysiological properties of this longer Ano1 isoform are unknown. Our aim was to determine the functional contribution of the newly identified exon to the Ca(2+) sensitivity and electrophysiological properties of Ano1. Constructs with [Ano1(+0)] or without [Ano1(-0)] the newly identified exon were transfected into human embryonic kidney-293 cells. Voltage-clamp electrophysiology was used to determine voltage- and time-dependent parameters of whole cell Cl(-) currents between isoforms with varying concentrations of intracellular Ca(2+), extracellular anions, or Cl(-) channel inhibitors. We found that exon 0 did not change voltage sensitivity and had no impact on the relative permeability of Ano1 to most anions. Ano1(+0) exhibited greater changes in current density but lesser changes in kinetics than Ano1(-0) in response to varying intracellular Ca(2+). The CACC inhibitor niflumic acid inhibited current with greater efficacy and higher potency against Ano1(+0) compared with Ano1(-0). Likewise, the Ano1 inhibitor T16Ainh-A01 reduced Ano1(+0) more than Ano1(-0). In conclusion, human Ano1 containing exon 0 imparts its Cl(-) current with greater sensitivity to intracellular Ca(2+) and CACC inhibitors.
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19
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Pang CL, Yuan HB, Cao TG, Su JG, Chen YF, Liu H, Yu H, Zhang HL, Zhan Y, An HL, Han YB. Molecular simulation assisted identification of Ca(2+) binding residues in TMEM16A. J Comput Aided Mol Des 2015; 29:1035-43. [PMID: 26481648 DOI: 10.1007/s10822-015-9876-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/12/2015] [Indexed: 01/31/2023]
Abstract
Calcium-activated chloride channels (CaCCs) play vital roles in a variety of physiological processes. Transmembrane protein 16A (TMEM16A) has been confirmed as the molecular counterpart of CaCCs which greatly pushes the molecular insights of CaCCs forward. However, the detailed mechanism of Ca(2+) binding and activating the channel is still obscure. Here, we utilized a combination of computational and electrophysiological approaches to discern the molecular mechanism by which Ca(2+) regulates the gating of TMEM16A channels. The simulation results show that the first intracellular loop serves as a Ca(2+) binding site including D439, E444 and E447. The experimental results indicate that a novel residue, E447, plays key role in Ca(2+) binding. Compared with WT TMEM16A, E447Y produces a 30-fold increase in EC50 of Ca(2+) activation and leads to a 100-fold increase in Ca(2+) concentrations that is needed to fully activate the channel. The following steered molecular dynamic (SMD) simulation data suggests that the mutations at 447 reduce the Ca(2+) dissociation energy. Our results indicated that both the electrical property and the size of the side-chain at residue 447 have significant effects on Ca(2+) dependent gating of TMEM16A.
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Affiliation(s)
- Chun-Li Pang
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Hong-Bo Yuan
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Tian-Guang Cao
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Ji-Guo Su
- School of Sciences, Yanshan University, Qinhuangdao, China
| | - Ya-Fei Chen
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Hui Liu
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Hui Yu
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
| | - Hai-Ling Zhang
- Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China
- The Key Laboratory of Pharmacology and Toxicology for New Drug, Shijiazhuang, Hebei Province, China
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Yong Zhan
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China.
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China.
| | - Hai-Long An
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China.
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China.
| | - Yue-Bin Han
- Key laboratory of Molecular Biophysics, Tianjin, Hebei Province, China
- Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, China
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20
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Lee J, Jung J, Tak MH, Wee J, Lee B, Jang Y, Chun H, Yang DJ, Yang YD, Park SH, Han BW, Hyun S, Yu J, Cho H, Hartzell HC, Oh U. Two helices in the third intracellular loop determine anoctamin 1 (TMEM16A) activation by calcium. Pflugers Arch 2014; 467:1677-87. [PMID: 25231974 PMCID: PMC4502317 DOI: 10.1007/s00424-014-1603-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 11/24/2022]
Abstract
Anoctamin 1 (ANO1)/TMEM16A is a Cl− channel activated by intracellular Ca2+ mediating numerous physiological functions. However, little is known of the ANO1 activation mechanism by Ca2+. Here, we demonstrate that two helices, “reference” and “Ca2+ sensor” helices in the third intracellular loop face each other with opposite charges. The two helices interact directly in a Ca2+-dependent manner. Positively and negatively charged residues in the two helices are essential for Ca2+-dependent activation because neutralization of these charges change the Ca2+ sensitivity. We now predict that the Ca2+ sensor helix attaches to the reference helix in the resting state, and as intracellular Ca2+ rises, Ca2+ acts on the sensor helix, which repels it from the reference helix. This Ca2+-dependent push-pull conformational change would be a key electromechanical movement for gating the ANO1 channel. Because chemical activation of ANO1 is viewed as an alternative means of rescuing cystic fibrosis, understanding its gating mechanism would be useful in developing novel treatments for cystic fibrosis.
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Affiliation(s)
- Jesun Lee
- Sensory Research Center, Creative Research Initiatives, College of Pharmacy, Seoul National University, Seoul, South Korea
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