1
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Xu M, Neelands T, Powers AS, Liu Y, Miller SD, Pintilie GD, Bois JD, Dror RO, Chiu W, Maduke M. CryoEM structures of the human CLC-2 voltage-gated chloride channel reveal a ball-and-chain gating mechanism. eLife 2024; 12:RP90648. [PMID: 38345841 PMCID: PMC10942593 DOI: 10.7554/elife.90648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024] Open
Abstract
CLC-2 is a voltage-gated chloride channel that contributes to electrical excitability and ion homeostasis in many different tissues. Among the nine mammalian CLC homologs, CLC-2 is uniquely activated by hyperpolarization, rather than depolarization, of the plasma membrane. The molecular basis for the divergence in polarity of voltage gating among closely related homologs has been a long-standing mystery, in part because few CLC channel structures are available. Here, we report cryoEM structures of human CLC-2 at 2.46 - 2.76 Å, in the presence and absence of the selective inhibitor AK-42. AK-42 binds within the extracellular entryway of the Cl--permeation pathway, occupying a pocket previously proposed through computational docking studies. In the apo structure, we observed two distinct conformations involving rotation of one of the cytoplasmic C-terminal domains (CTDs). In the absence of CTD rotation, an intracellular N-terminal 15-residue hairpin peptide nestles against the TM domain to physically occlude the Cl--permeation pathway. This peptide is highly conserved among species variants of CLC-2 but is not present in other CLC homologs. Previous studies suggested that the N-terminal domain of CLC-2 influences channel properties via a "ball-and-chain" gating mechanism, but conflicting data cast doubt on such a mechanism, and thus the structure of the N-terminal domain and its interaction with the channel has been uncertain. Through electrophysiological studies of an N-terminal deletion mutant lacking the 15-residue hairpin peptide, we support a model in which the N-terminal hairpin of CLC-2 stabilizes a closed state of the channel by blocking the cytoplasmic Cl--permeation pathway.
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Affiliation(s)
- Mengyuan Xu
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Torben Neelands
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Alexander S Powers
- Department of Chemistry, Stanford UniversityStanfordUnited States
- Department of Computer Science, Stanford UniversityStanfordUnited States
- Department of Structural Biology, Stanford UniversityStanfordUnited States
- Institute for Computational and Mathematical Engineering, Stanford UniversityStanfordUnited States
| | - Yan Liu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford UniversityStanfordUnited States
| | - Steven D Miller
- Department of Chemistry, Stanford UniversityStanfordUnited States
| | - Grigore D Pintilie
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford UniversityStanfordUnited States
| | - J Du Bois
- Department of Chemistry, Stanford UniversityStanfordUnited States
| | - Ron O Dror
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
- Department of Computer Science, Stanford UniversityStanfordUnited States
- Department of Structural Biology, Stanford UniversityStanfordUnited States
- Institute for Computational and Mathematical Engineering, Stanford UniversityStanfordUnited States
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford UniversityStanfordUnited States
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford UniversityStanfordUnited States
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
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2
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Sapio MR, King DM, Staedtler ES, Maric D, Jahanipour J, Kurochkina NA, Manalo AP, Ghetti A, Mannes AJ, Iadarola MJ. Expression pattern analysis and characterization of the hereditary sensory and autonomic neuropathy 2 A (HSAN2A) gene with no lysine kinase (WNK1) in human dorsal root ganglion. Exp Neurol 2023; 370:114552. [PMID: 37793538 DOI: 10.1016/j.expneurol.2023.114552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/20/2023] [Accepted: 09/27/2023] [Indexed: 10/06/2023]
Abstract
Inherited painless neuropathies arise due to genetic insults that either block the normal signaling of or destroy the sensory afferent neurons in the dorsal root ganglion (DRG) responsible for transducing noxious stimuli. Complete loss of these neurons leads to profound insensitivity to all sensory modalities including pain. Hereditary sensory and autonomic neuropathy type 2 (HSNAII) is a rare genetic neuropathy characterized by a progressive distal early onset sensory loss. This syndrome is caused by autosomal recessive mutations in the with-no-lysine protein kinase 1 (WNK1) serine-threonine kinase gene. Of interest, disease-associated mutations are found in the large exon, termed "HSN2," which encodes a 498 amino acid domain C-terminal to the kinase domain. These mutations lead to truncation of the HSN2-containing proteins through the addition of an early stop codon (nonsense mutation) leading to loss of the C-terminal domains of this large protein. The present study evaluates the transcripts, gene structure, and protein structure of HSN2-containing WNK1 splice variants in DRG and spinal cord in order to establish the basal expression patterns of WNK1 and HSN2-containing WNK1 splice variants using multiplex fluorescent situ hybridization. We hypothesized that these transcripts would be enriched in pain-sensing DRG neurons, and, potentially, that enrichment in nociceptive neurons was responsible for the painless phenotypes observed. However, our in-depth analyses revealed that the HSN2-WNK1 splice variants were ubiquitously expressed but were not enriched in tachykinin 1-expressing C-fiber neurons, a class of neurons with a highly nociceptive character. We subsequently identified other subpopulations of DRG neurons with higher levels of HSN2-WNK1 expression, including mechanosensory large fibers. These data are inconsistent with the hypothesis that this transcript is enriched in nociceptive fibers, and instead suggest it may be related to general axon maintenance, or that nociceptive fibers are more sensitive to the genetic insult. These findings clarify the molecular and cellular expression pattern of this painless neuropathy gene in human tissue.
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Affiliation(s)
- Matthew R Sapio
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Diana M King
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ellen S Staedtler
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dragan Maric
- National Institute of Neurological Disorders and Stroke, Flow and Imaging Cytometry Core Facility, Bethesda, MD 20892, USA
| | - Jahandar Jahanipour
- National Institute of Neurological Disorders and Stroke, Flow and Imaging Cytometry Core Facility, Bethesda, MD 20892, USA
| | | | - Allison P Manalo
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Andrew J Mannes
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael J Iadarola
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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3
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Xu M, Neelands T, Powers AS, Liu Y, Miller SD, Pintilie G, Bois JD, Dror RO, Chiu W, Maduke M. CryoEM structures of the human CLC-2 voltage gated chloride channel reveal a ball and chain gating mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.13.553136. [PMID: 37645939 PMCID: PMC10462068 DOI: 10.1101/2023.08.13.553136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
CLC-2 is a voltage-gated chloride channel that contributes to electrical excitability and ion homeostasis in many different mammalian tissues and cell types. Among the nine mammalian CLC homologs, CLC-2 is uniquely activated by hyperpolarization, rather than depolarization, of the plasma membrane. The molecular basis for the divergence in polarity of voltage gating mechanisms among closely related CLC homologs has been a long-standing mystery, in part because few CLC channel structures are available, and those that exist exhibit high conformational similarity. Here, we report cryoEM structures of human CLC-2 at 2.46 - 2.76 Å, in the presence and absence of the potent and selective inhibitor AK-42. AK-42 binds within the extracellular entryway of the Cl--permeation pathway, occupying a pocket previously proposed through computational docking studies. In the apo structure, we observed two distinct apo conformations of CLC-2 involving rotation of one of the cytoplasmic C-terminal domains (CTDs). In the absence of CTD rotation, an intracellular N-terminal 15-residue hairpin peptide nestles against the TM domain to physically occlude the Cl--permeation pathway from the intracellular side. This peptide is highly conserved among species variants of CLC-2 but is not present in any other CLC homologs. Previous studies suggested that the N-terminal domain of CLC-2 influences channel properties via a "ball-and-chain" gating mechanism, but conflicting data cast doubt on such a mechanism, and thus the structure of the N-terminal domain and its interaction with the channel has been uncertain. Through electrophysiological studies of an N-terminal deletion mutant lacking the 15-residue hairpin peptide, we show that loss of this short sequence increases the magnitude and decreases the rectification of CLC-2 currents expressed in mammalian cells. Furthermore, we show that with repetitive hyperpolarization WT CLC-2 currents increase in resemblance to the hairpin-deleted CLC-2 currents. These functional results combined with our structural data support a model in which the N-terminal hairpin of CLC-2 stabilizes a closed state of the channel by blocking the cytoplasmic Cl--permeation pathway.
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Affiliation(s)
- Mengyuan Xu
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Torben Neelands
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Alexander S. Powers
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Department of Computer Science, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA 94305
| | - Yan Liu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park 94025
| | - Steven D. Miller
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Grigore Pintilie
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford University, Stanford, 94305
| | - J. Du Bois
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Ron O. Dror
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
- Department of Computer Science, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA 94305
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park 94025
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford University, Stanford, 94305
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
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Mura-Escorche G, Perdomo-Ramírez A, Ramos-Trujillo E, Trujillo-Frías CJ, Claverie-Martín F. Characterization of pre-mRNA Splicing Defects Caused by CLCN5 and OCRL Mutations and Identification of Novel Variants Associated with Dent Disease. Biomedicines 2023; 11:3082. [PMID: 38002082 PMCID: PMC10669864 DOI: 10.3390/biomedicines11113082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
Dent disease (DD) is an X-linked renal tubulopathy characterized by low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis and progressive renal failure. Two-thirds of cases are associated with inactivating variants in the CLCN5 gene (Dent disease 1, DD1) and a few present variants in the OCRL gene (Dent disease 2, DD2). The aim of the present study was to test the effect on the pre-mRNA splicing process of DD variants, described here or in the literature, and describe the clinical and genotypic features of thirteen unrelated patients with suspected DD. All patients presented tubular proteinuria, ten presented hypercalciuria and five had nephrolithiasis or nephrocalcinosis. CLCN5 and OCRL genes were analyzed by Sanger sequencing. Nine patients showed variants in CLCN5 and four in OCRL; eight of these were new. Bioinformatics tools were used to select fifteen variants with a potential effect on pre-mRNA splicing from our patients' group and from the literature, and were experimentally tested using minigene assays. Results showed that three exonic missense mutations and two intronic variants affect the mRNA splicing process. Our findings widen the genotypic spectrum of DD and provide insight into the impact of variants causing DD.
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Affiliation(s)
- Glorián Mura-Escorche
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
- Departamento de Medicina Interna, Dermatología y Psiquiatría, Facultad de Medicina, Universidad de la Laguna, 38071 Santa Cruz de Tenerife, Spain
| | - Ana Perdomo-Ramírez
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
| | - Elena Ramos-Trujillo
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
- Departamento de Medicina Física y Farmacología, Facultad de Medicina, Universidad de la Laguna, 38071 Santa Cruz de Tenerife, Spain
| | - Carmen Jane Trujillo-Frías
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
| | - Félix Claverie-Martín
- Unidad de Investigación, Grupo RenalTube, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (G.M.-E.); (A.P.-R.); (C.J.T.-F.)
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5
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Zhang B, Zhang S, Polovitskaya MM, Yi J, Ye B, Li R, Huang X, Yin J, Neuens S, Balfroid T, Soblet J, Vens D, Aeby A, Li X, Cai J, Song Y, Li Y, Tartaglia M, Li Y, Jentsch TJ, Yang M, Liu Z. Molecular basis of ClC-6 function and its impairment in human disease. SCIENCE ADVANCES 2023; 9:eadg4479. [PMID: 37831762 PMCID: PMC10575590 DOI: 10.1126/sciadv.adg4479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 09/08/2023] [Indexed: 10/15/2023]
Abstract
ClC-6 is a late endosomal voltage-gated chloride-proton exchanger that is predominantly expressed in the nervous system. Mutated forms of ClC-6 are associated with severe neurological disease. However, the mechanistic role of ClC-6 in normal and pathological states remains largely unknown. Here, we present cryo-EM structures of ClC-6 that guided subsequent functional studies. Previously unrecognized ATP binding to cytosolic ClC-6 domains enhanced ion transport activity. Guided by a disease-causing mutation (p.Y553C), we identified an interaction network formed by Y553/F317/T520 as potential hotspot for disease-causing mutations. This was validated by the identification of a patient with a de novo pathogenic variant p.T520A. Extending these findings, we found contacts between intramembrane helices and connecting loops that modulate the voltage dependence of ClC-6 gating and constitute additional candidate regions for disease-associated gain-of-function mutations. Besides providing insights into the structure, function, and regulation of ClC-6, our work correctly predicts hotspots for CLCN6 mutations in neurodegenerative disorders.
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Affiliation(s)
- Bing Zhang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Sensen Zhang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Maya M. Polovitskaya
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), 13125 Berlin, Germany
| | - Jingbo Yi
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Binglu Ye
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Ruochong Li
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Xueying Huang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Jian Yin
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Sebastian Neuens
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Tom Balfroid
- Department of Pediatric Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Julie Soblet
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Department of Genetics, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Daphné Vens
- Pediatric Intensive Care Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Alec Aeby
- Department of Pediatric Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Xiaoling Li
- Wuya College of Innovation, Shenyang Pharmaceutical University, 110016 Shenyang, China
| | - Jinjin Cai
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203 Shanghai, China
| | - Yingcai Song
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Yuanxi Li
- Institute for Cognitive Neurodynamics, School of Mathematics, East China University of Science and Technology, 200237 Shanghai, China
| | - Marco Tartaglia
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Yang Li
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203 Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), 13125 Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
- Cryo-EM Facility Center, Southern University of Science & Technology, 518055 Shenzhen, Guangdong, China
| | - Zhiqiang Liu
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
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6
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Coppola MA, Pusch M, Imbrici P, Liantonio A. Small Molecules Targeting Kidney ClC-K Chloride Channels: Applications in Rare Tubulopathies and Common Cardiovascular Diseases. Biomolecules 2023; 13:biom13040710. [PMID: 37189456 DOI: 10.3390/biom13040710] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/15/2023] [Accepted: 04/19/2023] [Indexed: 05/17/2023] Open
Abstract
Given the key role played by ClC-K chloride channels in kidney and inner ear physiology and pathology, they can be considered important targets for drug discovery. Indeed, ClC-Ka and ClC-Kb inhibition would interfere with the urine countercurrent concentration mechanism in Henle's loop, which is responsible for the reabsorption of water and electrolytes from the collecting duct, producing a diuretic and antihypertensive effect. On the other hand, ClC-K/barttin channel dysfunctions in Bartter Syndrome with or without deafness will require the pharmacological recovery of channel expression and/or activity. In these cases, a channel activator or chaperone would be appealing. Starting from a brief description of the physio-pathological role of ClC-K channels in renal function, this review aims to provide an overview of the recent progress in the discovery of ClC-K channel modulators.
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Affiliation(s)
| | - Michael Pusch
- Institute of Biophysics, National Research Council, 16149 Genova, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", 70125 Bari, Italy
| | - Antonella Liantonio
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", 70125 Bari, Italy
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7
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Ni J, Zhu Y, Lin F, Guan W, Jin J, Li Y, Guo G. A novel CLCN5 frame shift mutation responsible for Dent disease 1: Case report. Front Pediatr 2022; 10:1043502. [PMID: 36452359 PMCID: PMC9702988 DOI: 10.3389/fped.2022.1043502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Dent disease is a group of inherited X-linked recessive renal tubular disorders. This group of disorders is characterized by low molecular weight proteinuria (LMWP), nephrocalcinosis, hypercalciuria and renal failure. CASE PRESENTATION Here we report one 11-year-old Chinese boy (proband) and one 13-year-old Chinese boy who was proband's cousin, both presented with massive proteinuria. Further laboratory examinations revealed a lack of nephrocalcinosis, nor any other signs of tubular dysfunction, but only LMWP and hypercalciuria. There was no abnormality in growth, renal function or mineral density of the bones. A novel deletion (c.1448delG) in the CLCN5 gene was identified, resulting in a frame shift mutation (p.Gly483fs). The proband's and his cousin's mothers were found to be the carrier of this mutation. CONCLUSIONS In this study, we have found a novel frameshift mutation (c. 1448delG) at exon 11 of the CLCN5 gene which leads to Dent disease 1, expanding the spectrum of CLCN5 mutations.
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Affiliation(s)
- Jiajia Ni
- Department of Pediatric Nephrology, Rheumatology and Immunology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yaju Zhu
- Department of Pediatric Nephrology, Rheumatology and Immunology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Fujun Lin
- Department of Nephrology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Wenbin Guan
- Department of Pathology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Jin
- Department of Pediatric Nephrology, Rheumatology and Immunology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yufeng Li
- Department of Pediatric Nephrology, Rheumatology and Immunology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Guimei Guo
- Department of Pediatric Nephrology, Rheumatology and Immunology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
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8
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Kouyoumdzian NM, Kim G, Rudi MJ, Rukavina Mikusic NL, Fernández BE, Choi MR. Clues and new evidences in arterial hypertension: unmasking the role of the chloride anion. Pflugers Arch 2021; 474:155-176. [PMID: 34966955 DOI: 10.1007/s00424-021-02649-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 02/06/2023]
Abstract
The present review will focus on the role of chloride anion in cardiovascular disease, with special emphasis in the development of hypertensive disease and vascular inflammation. It is known that acute and chronic overload of sodium chloride increase blood pressure and have pro-inflammatory and pro-fibrotic effects on different target organs, but it is unknown how chloride may influence these processes. Chloride anion is the predominant anion in the extracellular fluid and its intracellular concentration is dynamically regulated. As the queen of the electrolytes, it is of crucial importance to understand the physiological mechanisms that regulate the cellular handling of this anion including the different transporters and cellular chloride channels, which exert a variety of functions, such as regulation of cellular proliferation, differentiation, migration, apoptosis, intracellular pH and cellular redox state. In this article, we will also review the relationship between dietary, serum and intracellular chloride and how these different sources of chloride in the organism are affected in hypertension and their impact on cardiovascular disease. Additionally, we will discuss the approach of potential strategies that affect chloride handling and its potential effect on cardiovascular system, including pharmacological blockade of chloride channels and non-pharmacological interventions by replacing chloride by another anion.
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Affiliation(s)
- Nicolás Martín Kouyoumdzian
- Universidad de Buenos Aires, CONICET, Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional (IATIMET), Buenos Aires, Argentina.
| | - Gabriel Kim
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Julieta Rudi
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Natalia Lucía Rukavina Mikusic
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Marcelo Roberto Choi
- Universidad de Buenos Aires, CONICET, Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional (IATIMET), Buenos Aires, Argentina.,Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto Universitario de Ciencias de La Salud, Fundación H.A. Barceló, Buenos Aires, Argentina
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9
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Hao Q, Yang Y, Shan Z, Chen H, Zhang C, Chen L, Yuan S, Zhang X, Chen S, Yang Z, Qiu D, Zhou X. Genome-Wide Investigation and Expression Profiling Under Abiotic Stresses of a Soybean Unknown Function (DUF21) and Cystathionine-β-Synthase (CBS) Domain-Containing Protein Family. Biochem Genet 2021; 59:83-113. [PMID: 32778975 PMCID: PMC7846513 DOI: 10.1007/s10528-020-09991-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 07/27/2020] [Indexed: 01/26/2023]
Abstract
Cystathionine-β-synthase (CBS) domain-containing proteins (CDCPs) constitute a large family in plants, and members of this family have been implicated in a variety of biological processes. However, the precise functions and the underlying mechanisms of most members of this family in plants remain to be elucidated. CBSDUF proteins belong to the CDCP superfamily, which contains one domain of unknown function (DUF21) and an N terminus that is adjacent to two intracellular CBS domains. In this study, a comprehensive genome database analysis of soybean was performed to investigate the role(s) of these CBSDUFs and to explore their nomenclature, classification, chromosomal distribution, exon-intron organization, protein structure, and phylogenetic relationships; the analysis identified a total of 18 putative CBSDUF genes. Using specific protein domains and phylogenetic analysis, the CBSDUF gene family was subdivided into eight groups. The soybean CBSDUF genes showed an uneven distribution on 12 chromosomes of Glycine max. RNA-seq transcriptome data from different tissues in public databases revealed tissue-specific and differential expression profiles of the GmCBSDUFs, and qPCR analysis revealed that certain groups of soybean CBSDUFs are likely involved in specific stress responses. In addition, GmCBSDUF3 transgenic Arabidopsis was subjected to phenotypic analysis under NaCl, PEG, and ABA stress treatments. The overexpression of GmCBSDUF3 could enhance tolerance to drought and salt stress in Arabidopsis. This study presents a first comprehensive look at soybean CBSDUF proteins and provides valuable resources for functionally elucidating this protein subgroup within the CBS domain-containing protein family.
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Affiliation(s)
- Qingnan Hao
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Yanyan Yang
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Zhihui Shan
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Haifeng Chen
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Chanjuan Zhang
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Limiao Chen
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Songli Yuan
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Xiaojuan Zhang
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Shuilian Chen
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Zhonglu Yang
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Dezhen Qiu
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China
| | - Xinan Zhou
- Key Laboratory of Oil Crop Biology, Ministry of Agriculture, Wuhan, 430062, China.
- Oil Crops Research Institute of Chinese Academy of Agriculture Sciences, Wuhan, China.
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10
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Park C, Sakurai Y, Sato H, Kanda S, Iino Y, Kunitomo H. Roles of the ClC chloride channel CLH-1 in food-associated salt chemotaxis behavior of C. elegans. eLife 2021; 10:e55701. [PMID: 33492228 PMCID: PMC7834019 DOI: 10.7554/elife.55701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 01/04/2021] [Indexed: 01/19/2023] Open
Abstract
The ability of animals to process dynamic sensory information facilitates foraging in an ever-changing environment. However, molecular and neural mechanisms underlying such ability remain elusive. The ClC anion channels/transporters play a pivotal role in cellular ion homeostasis across all phyla. Here, we find a ClC chloride channel is involved in salt concentration chemotaxis of Caenorhabditis elegans. Genetic screening identified two altered-function mutations of clh-1 that disrupt experience-dependent salt chemotaxis. Using genetically encoded fluorescent sensors, we demonstrate that CLH-1 contributes to regulation of intracellular anion and calcium dynamics of salt-sensing neuron, ASER. The mutant CLH-1 reduced responsiveness of ASER to salt stimuli in terms of both temporal resolution and intensity, which disrupted navigation strategies for approaching preferred salt concentrations. Furthermore, other ClC genes appeared to act redundantly in salt chemotaxis. These findings provide insights into the regulatory mechanism of neuronal responsivity by ClCs that contribute to modulation of navigation behavior.
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Affiliation(s)
- Chanhyun Park
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Yuki Sakurai
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Hirofumi Sato
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Shinji Kanda
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of TokyoChibaJapan
| | - Yuichi Iino
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Hirofumi Kunitomo
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
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11
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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12
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Garcia DCG, Longden TA. Ion channels in capillary endothelium. CURRENT TOPICS IN MEMBRANES 2020; 85:261-300. [PMID: 32402642 DOI: 10.1016/bs.ctm.2020.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vascular beds are anatomically and functionally compartmentalized into arteries, capillaries, and veins. The bulk of the vasculature consists of the dense, anastomosing capillary network, composed of capillary endothelial cells (cECs) that are intimately associated with the parenchyma. Despite their abundance, the ion channel expression and function and Ca2+ signaling behaviors of capillaries have only recently begun to be explored in detail. Here, we discuss the established and emerging roles of ion channels and Ca2+ signaling in cECs. By mining a publicly available RNA-seq dataset, we outline the wide variety of ion channel genes that are expressed in these cells, which potentially imbue capillaries with a broad range of sensing and signal transduction capabilities. We also underscore subtle but critical differences between cEC and arteriolar EC ion channel expression that likely underlie key functional differences in ECs at these different levels of the vascular tree. We focus our discussion on the cerebral vasculature, but the findings and principles being elucidated in this area likely generalize to other vascular beds.
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Affiliation(s)
- Daniela C G Garcia
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States.
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13
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Ye Q, Shen Q, Rao J, Zhang A, Zheng B, Liu X, Shen Y, Chen Z, Wu Y, Hou L, Jian S, Wei M, Ma M, Sun S, Li Q, Dang X, Wang Y, Xu H, Mao J. Multicenter study of the clinical features and mutation gene spectrum of Chinese children with Dent disease. Clin Genet 2020; 97:407-417. [PMID: 31674016 DOI: 10.1111/cge.13663] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/07/2019] [Accepted: 10/12/2019] [Indexed: 01/21/2023]
Abstract
Dent disease is a rare X-linked recessive inherited tubular disease. In this multicenter study, the clinical presentation and genetic background of Chinese children with Dent disease are studied to improve the cognition and diagnostic ability of pediatricians. In this prospective cohort, we described the genotype and phenotype of a national cohort composed of 45 pediatric probands with Dent disease belonging to 45 families from 12 different regions of China recruited from 2014 to 2018 by building up the multicenter registration system. The CLCN5 gene from 32 affected families revealed 28 different mutations. The OCRL gene from 13 affected families revealed 13 different mutations. The incidence of low-molecular-weight proteinuria (LMWP) in both Dent disease type 1 populations and Dent disease type 2 populations was 100.0%; however, the incidence of other manifestations was not high, which was similar to previously reported data. Therefore, LMWP is a key clinical feature that should alert clinicians to the possibility of Dent disease. A high amount of LMWP combined with positive gene test results can be used as the diagnostic criteria for this disease. The diagnostic criteria are helpful in reducing the missed diagnosis of this disease and are beneficial for protecting the renal function of these patients through early diagnosis and early intervention.
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Affiliation(s)
- Qing Ye
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National clinical research center for child health, Hangzhou, China
| | - Qian Shen
- Department of Nephrology, Children's Hospital of Fudan University, Shanghai, China.,Shanghai Kidney Development and Pediatric Kidney Disease Research Center, Shanghai, China.,Shanghai Key Lab of Birth Defect, Children's Hospital of Fudan University, Shanghai, China
| | - Jia Rao
- Department of Nephrology, Children's Hospital of Fudan University, Shanghai, China.,Shanghai Kidney Development and Pediatric Kidney Disease Research Center, Shanghai, China.,Shanghai Key Lab of Birth Defect, Children's Hospital of Fudan University, Shanghai, China
| | - Aihua Zhang
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University Nanjing, China
| | - Xiaorong Liu
- Department of Nephrology, Bejing Children's Hospital Affiliated to Capital University of Medical Science, Beijing, China.,Beijing Children's Key Laboratory of Chronic Kidney Disease and Blood Purification, Beijing, China
| | - Ying Shen
- Department of Nephrology, Bejing Children's Hospital Affiliated to Capital University of Medical Science, Beijing, China.,Beijing Children's Key Laboratory of Chronic Kidney Disease and Blood Purification, Beijing, China
| | - Zhi Chen
- Department of Nephrology, Bejing Children's Hospital Affiliated to Capital University of Medical Science, Beijing, China.,Beijing Children's Key Laboratory of Chronic Kidney Disease and Blood Purification, Beijing, China
| | - Yubing Wu
- Department of Pediatric Nephrology and Rheumatology, Shengfing Hospital of China Medical University, Shenyang, China
| | - Ling Hou
- Department of Pediatric Nephrology and Rheumatology, Shengfing Hospital of China Medical University, Shenyang, China
| | - Shan Jian
- Department of Pediatrics, Peking Union Medical College Hospital, Beijing, China
| | - Min Wei
- Department of Pediatrics, Peking Union Medical College Hospital, Beijing, China
| | - Mingsheng Ma
- Department of Pediatrics, Peking Union Medical College Hospital, Beijing, China
| | - Shuzhen Sun
- Department of Pediatric, Nephrology, Rheumatism and Immunology, Shandong Provincial Hospital, Jinan, China
| | - Qian Li
- Department of Pediatric, Nephrology, Rheumatism and Immunology, Shandong Provincial Hospital, Jinan, China
| | - Xiqiang Dang
- Department of Pediatric, Xiangya Hospital Central South University, Changsha, China
| | - Ying Wang
- Department of Pediatric, Xiangya Hospital Central South University, Changsha, China
| | - Hong Xu
- Department of Nephrology, Children's Hospital of Fudan University, Shanghai, China.,Shanghai Kidney Development and Pediatric Kidney Disease Research Center, Shanghai, China.,Shanghai Key Lab of Birth Defect, Children's Hospital of Fudan University, Shanghai, China
| | - Jianhua Mao
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National clinical research center for child health, Hangzhou, China
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14
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Milla CP, De Castro CP, Gómez-González C, Martínez-Montero P, Pascual Pascual SI, Molano Mateos J. Myotonia congenita: mutation spectrum of CLCN1 in Spanish patients. J Genet 2019; 98:71. [PMID: 31544778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Myotonia congenita (MC) is a Mendelian inherited genetic disease caused by the mutations in the CLCN1 gene, encoding the main skeletal muscle ion chloride channel (ClC-1). The clinical diagnosis of MC should be suspected in patients presenting myotonia, warm-up phenomenon, a characteristic electromyographic pattern, and/or family history. Here, we describe the largest cohort of MC Spanish patients including their relatives (up to 102 individuals). Genetic testing was performed by CLCN1 sequencing and multiplex ligation-dependent probe amplification (MLPA). Analysis of selected exons of the SCN4A gene, causing paramyotonia congenita, was also performed. Mutation spectrum and analysis of a likely founder effect of c.180+3A>T was achieved by haplotype analysis and association tests. Twenty-eight different pathogenic variants were found in the CLCN1 gene, of which 21 were known mutations and seven not described. Gross deletions/duplications were not detected. Four probands had a pathogenic variant in SCN4A. Two main haplotypes were detected in c.180+3A>T carriers and no statistically significant differences were detected between case and control groups regarding the type of haplotype and its frequencies. A diagnostic yield of 51% was achieved; of which 88% had pathogenic variants in CLCN1 and 12% in SCN4A. The existence of a c.180+3A>T founder effect remains unsolved.
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Affiliation(s)
- Carmen Palma Milla
- Instituto de Genética Médica y Molecular, CIBERER, IdiPAZ, Hospital Universitario La Paz, Madrid 28046, Spain.
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15
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Palma Milla C, Prior De Castro C, Gómez-González C, Martínez-Montero P, I. Pascual Pascual S, Molano Mateos J. Myotonia congenita: mutation spectrum of CLCN1 in Spanish patients. J Genet 2019. [DOI: 10.1007/s12041-019-1115-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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16
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Elorza-Vidal X, Gaitán-Peñas H, Estévez R. Chloride Channels in Astrocytes: Structure, Roles in Brain Homeostasis and Implications in Disease. Int J Mol Sci 2019; 20:ijms20051034. [PMID: 30818802 PMCID: PMC6429410 DOI: 10.3390/ijms20051034] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/15/2019] [Accepted: 02/17/2019] [Indexed: 12/29/2022] Open
Abstract
Astrocytes are the most abundant cell type in the CNS (central nervous system). They exert multiple functions during development and in the adult CNS that are essential for brain homeostasis. Both cation and anion channel activities have been identified in astrocytes and it is believed that they play key roles in astrocyte function. Whereas the proteins and the physiological roles assigned to cation channels are becoming very clear, the study of astrocytic chloride channels is in its early stages. In recent years, we have moved from the identification of chloride channel activities present in astrocyte primary culture to the identification of the proteins involved in these activities, the determination of their 3D structure and attempts to gain insights about their physiological role. Here, we review the recent findings related to the main chloride channels identified in astrocytes: the voltage-dependent ClC-2, the calcium-activated bestrophin, the volume-activated VRAC (volume-regulated anion channel) and the stress-activated Maxi-Cl−. We discuss key aspects of channel biophysics and structure with a focus on their role in glial physiology and human disease.
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Affiliation(s)
- Xabier Elorza-Vidal
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
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17
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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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Altamura C, Lucchiari S, Sahbani D, Ulzi G, Comi GP, D'Ambrosio P, Petillo R, Politano L, Vercelli L, Mongini T, Dotti MT, Cardani R, Meola G, Lo Monaco M, Matthews E, Hanna MG, Carratù MR, Conte D, Imbrici P, Desaphy JF. The analysis of myotonia congenita mutations discloses functional clusters of amino acids within the CBS2 domain and the C-terminal peptide of the ClC-1 channel. Hum Mutat 2018; 39:1273-1283. [PMID: 29935101 DOI: 10.1002/humu.23581] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 11/10/2022]
Abstract
Myotonia congenita (MC) is a skeletal-muscle hyperexcitability disorder caused by loss-of-function mutations in the ClC-1 chloride channel. Mutations are scattered over the entire sequence of the channel protein, with more than 30 mutations located in the poorly characterized cytosolic C-terminal domain. In this study, we characterized, through patch clamp, seven ClC-1 mutations identified in patients affected by MC of various severities and located in the C-terminal region. The p.Val829Met, p.Thr832Ile, p.Val851Met, p.Gly859Val, and p.Leu861Pro mutations reside in the CBS2 domain, while p.Pro883Thr and p.Val947Glu are in the C-terminal peptide. We showed that the functional properties of mutant channels correlated with the clinical phenotypes of affected individuals. In addition, we defined clusters of ClC-1 mutations within CBS2 and C-terminal peptide subdomains that share the same functional defect: mutations between 829 and 835 residues and in residue 883 induced an alteration of voltage dependence, mutations between 851 and 859 residues, and in residue 947 induced a reduction of chloride currents, whereas mutations on 861 residue showed no obvious change in ClC-1 function. This study improves our understanding of the mechanisms underlying MC, sheds light on the role of the C-terminal region in ClC-1 function, and provides information to develop new antimyotonic drugs.
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Affiliation(s)
- Concetta Altamura
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Sabrina Lucchiari
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy.,Neurology Unit, IRCCS Fondazione Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Dalila Sahbani
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Gianna Ulzi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy.,Neurology Unit, IRCCS Fondazione Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy.,Neurology Unit, IRCCS Fondazione Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Paola D'Ambrosio
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, University of Campania, Naples, Italy
| | - Roberta Petillo
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, University of Campania, Naples, Italy
| | - Luisa Politano
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, University of Campania, Naples, Italy
| | - Liliana Vercelli
- Neuromuscular Unit, Department of Neurosciences, Hospital Città della Salute e della Scienza of Torino, University of Torino, Turin, Italy
| | - Tiziana Mongini
- Neuromuscular Unit, Department of Neurosciences, Hospital Città della Salute e della Scienza of Torino, University of Torino, Turin, Italy
| | - Maria Teresa Dotti
- Unit of Neurology and Neurometabolic Disorders, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, IRCCS Policlinico San Donato, Milan, Italy
| | - Mauro Lo Monaco
- Institute of Neurology, Catholic University of Sacred Heart, Polyclinic Gemelli, Rome, Italy.,MiA Onlus ("Miotonici in Associazione"), Portici, Italy
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Maria Rosaria Carratù
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Polyclinic, Bari, Italy
| | - Diana Conte
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Polyclinic, Bari, Italy
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19
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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Park E, MacKinnon R. Structure of the CLC-1 chloride channel from Homo sapiens. eLife 2018; 7:36629. [PMID: 29809153 PMCID: PMC6019066 DOI: 10.7554/elife.36629] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/15/2018] [Indexed: 11/18/2022] Open
Abstract
CLC channels mediate passive Cl− conduction, while CLC transporters mediate active Cl− transport coupled to H+ transport in the opposite direction. The distinction between CLC-0/1/2 channels and CLC transporters seems undetectable by amino acid sequence. To understand why they are different functionally we determined the structure of the human CLC-1 channel. Its ‘glutamate gate’ residue, known to mediate proton transfer in CLC transporters, adopts a location in the structure that appears to preclude it from its transport function. Furthermore, smaller side chains produce a wider pore near the intracellular surface, potentially reducing a kinetic barrier for Cl− conduction. When the corresponding residues are mutated in a transporter, it is converted to a channel. Finally, Cl− at key sites in the pore appear to interact with reduced affinity compared to transporters. Thus, subtle differences in glutamate gate conformation, internal pore diameter and Cl− affinity distinguish CLC channels and transporters. Channels and transporters are two classes of proteins that transport molecules and ions – collectively referred to as “substrates” – across cell membranes. Channels form a pore in the membrane and the substrates diffuse through passively. Transporters, on the other hand, actively pump substrates across a membrane, consuming energy in the process. Thus, channels and transporters work in distinct ways. Channels and transporters most often have unrelated structures, but there are rare examples of both existing within the same family of structurally similar proteins. CLC proteins, for example, include both chloride ion channels and transporters that pump chloride ions in one direction by harnessing the energy from hydrogen ions flowing in the other direction. It remains unclear why some CLC proteins work as channels while others are transporters, especially since the two seem indistinguishable on the basis of the order of their amino acids – the building blocks of all proteins. The conservation of the amino acid sequences implies they are structurally very similar. How then can different members perform such energetically distinct processes? Park and MacKinnon now show that the answer to this question serves as a reminder of how subtle nature can be. Indeed, while the structure of a human CLC channel (called CLC-1) is indeed similar to those of CLC transporters, one amino acid adopts a unique shape that explains why the protein cannot act as a transporter. This specific amino acid, a glutamate, is central to the exchange of chloride and hydrogen ions in CLC transporters. Park and MacKinnon show that its conformation in the CLC-1 channel stops this exchange, while leaving the pore open for the passive transport of chloride ions. Also, two other amino acids along the ion diffusion pathway in the CLC channel are smaller than their counterparts in CLC transporters, and so allow chloride ions to diffuse through more quickly. Lastly, Park and MacKinnon also note that channels do not require a wide pore: instead ions can still flow rapidly through a narrow pore if the chemical environment inside permits it. CLC proteins perform a number of important roles in humans, and mutations in CLC-encoding genes underlie numerous heritable diseases. It remains too early to know how this mechanistic study may or may not impact treatments, yet the findings will likely interest scientists working on ion conduction mechanisms and the evolution of molecular function.
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Affiliation(s)
- Eunyong Park
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
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Gaitán-Peñas H, Armand-Ugón M, Macaya A, Estévez R. CLCN1 Myotonia congenita mutation with a variable pattern of inheritance suggests a novel mechanism of dominant myotonia. Muscle Nerve 2018; 58:157-160. [PMID: 29424939 DOI: 10.1002/mus.26098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2018] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Mutations in CLCN1 cause recessive or dominant forms of myotonia congenita (MC). Some mutations have been found to exhibit both patterns of inheritance but the mechanism explaining this behavior is unknown. METHODS A known recessive missense mutation, A493E, was identified in a family with dominant MC. The mutant p.A493E alone or in co-expression with wild-type (WT) ClC-1 was expressed in Xenopus oocytes. Currents were measured and biochemical assays were performed. RESULTS The mutant showed no significant activity and reduced total and plasma membrane (PM) protein levels. Co-expression with the mutant reduced the activity and PM levels of an engineered lower expression variant of ClC-1, whereas no effect was observed on a higher expression variant. DISCUSSION Our results suggest that the dominant effect of some CLCN1 mutations showing recessive or dominant inheritance patterns may be due to a dose-dependent defect in PM delivery of the WT channel. Muscle Nerve, 2018.
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Affiliation(s)
- Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Universitat de Barcelona (Institut de Neurociències), L'Hospitalet de Llobregat, Spain
- U-750, CIBERER, ISCIII, Barcelona, Spain
| | - Mercedes Armand-Ugón
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Universitat de Barcelona (Institut de Neurociències), L'Hospitalet de Llobregat, Spain
| | - Alfons Macaya
- Pediatric Neurology Research Group, Vall d'Hebron Research Institute, Hospital Universitari de Vall d'Hebron, Autonomous University of Barcelona, Barcelona, Spain
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, IDIBELL-Universitat de Barcelona (Institut de Neurociències), L'Hospitalet de Llobregat, Spain
- U-750, CIBERER, ISCIII, Barcelona, Spain
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Steinmann ME, Schmidt RS, Macêdo JP, Kunz Renggli C, Bütikofer P, Rentsch D, Mäser P, Sigel E. Identification and characterization of the three members of the CLC family of anion transport proteins in Trypanosoma brucei. PLoS One 2017; 12:e0188219. [PMID: 29244877 PMCID: PMC5731698 DOI: 10.1371/journal.pone.0188219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/02/2017] [Indexed: 11/19/2022] Open
Abstract
CLC type anion transport proteins are homo-dimeric or hetero-dimeric with an integrated transport function in each subunit. We have identified and partially characterized three members of this family named TbVCL1, TbVCL2 and TbVCL3 in Trypanosoma brucei. Among the human CLC family members, the T. brucei proteins display highest similarity to CLC-6 and CLC-7. TbVCL1, but not TbVCL2 and TbVCL3 is able to complement growth of a CLC-deficient Saccharomyces cerevisiae mutant. All TbVCL-HA fusion proteins localize intracellulary in procyclic form trypanosomes. TbVCL1 localizes close to the Golgi apparatus and TbVCL2 and TbVCL3 to the endoplasmic reticulum. Upon expression in Xenopus oocytes, all three proteins induce similar outward rectifying chloride ion currents. Currents are sensitive to low concentrations of DIDS, insensitive to the pH in the range 5.4 to 8.4 and larger in nitrate than in chloride medium.
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Affiliation(s)
- Michael E. Steinmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Remo S. Schmidt
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Juan P. Macêdo
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Christina Kunz Renggli
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Erwin Sigel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- * E-mail:
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Yamada T, Krzeminski M, Bozoky Z, Forman-Kay JD, Strange K. Role of CBS and Bateman Domains in Phosphorylation-Dependent Regulation of a CLC Anion Channel. Biophys J 2017; 111:1876-1886. [PMID: 27806269 DOI: 10.1016/j.bpj.2016.09.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 08/30/2016] [Accepted: 09/23/2016] [Indexed: 12/13/2022] Open
Abstract
Eukaryotic CLC anion channels and transporters are homodimeric proteins composed of multiple α-helical membrane domains and large cytoplasmic C-termini containing two cystathionine-β-synthase domains (CBS1 and CBS2) that dimerize to form a Bateman domain. The Bateman domains of adjacent CLC subunits interact to form a Bateman domain dimer. The functions of CLC CBS and Bateman domains are poorly understood. We utilized the Caenorhabditis elegans CLC-1/2/Ka/Kb anion channel homolog CLH-3b to characterize the regulatory roles of CLC cytoplasmic domains. CLH-3b activity is reduced by phosphorylation or deletion of a 14-amino-acid activation domain (AD) located on the linker connecting CBS1 and CBS2. We demonstrate here that phosphorylation-dependent reductions in channel activity require an intact Bateman domain dimer and concomitant phosphorylation or deletion of both ADs. Regulation of a CLH-3b AD deletion mutant is reconstituted by intracellular perfusion with recombinant 14-amino-acid AD peptides. The sulfhydryl reactive reagent 2-(trimethylammonium)ethyl methanethiosulfonate bromide (MTSET) alters in a phosphorylation-dependent manner the activity of channels containing single cysteine residues that are engineered into the short intracellular loop connecting membrane α-helices H and I (H-I loop), the AD, CBS1, and CBS2. In contrast, MTSET has no effect on channels in which cysteine residues are engineered into intracellular regions that are dispensable for regulation. These studies together with our previous work suggest that binding and unbinding of the AD to the Bateman domain dimer induces conformational changes that are transduced to channel membrane domains via the H-I loop. Our findings provide new, to our knowledge, insights into the roles of CLC Bateman domains and the structure-function relationships that govern the regulation of CLC protein activity by diverse ligands and signaling pathways.
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Affiliation(s)
- Toshiki Yamada
- MDI Biological Laboratory, Kathryn W. Davis Center for Regenerative Biology and Medicine, Salisbury Cove, Maine
| | - Mickael Krzeminski
- Department of Molecular Structure and Function, Hospital for Sick Kids, Toronto, Ontario
| | - Zoltan Bozoky
- Department of Molecular Structure and Function, Hospital for Sick Kids, Toronto, Ontario
| | - Julie D Forman-Kay
- Department of Molecular Structure and Function, Hospital for Sick Kids, Toronto, Ontario
| | - Kevin Strange
- MDI Biological Laboratory, Kathryn W. Davis Center for Regenerative Biology and Medicine, Salisbury Cove, Maine.
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Poroca DR, Pelis RM, Chappe VM. ClC Channels and Transporters: Structure, Physiological Functions, and Implications in Human Chloride Channelopathies. Front Pharmacol 2017; 8:151. [PMID: 28386229 PMCID: PMC5362633 DOI: 10.3389/fphar.2017.00151] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/09/2017] [Indexed: 02/04/2023] Open
Abstract
The discovery of ClC proteins at the beginning of the 1990s was important for the development of the Cl- transport research field. ClCs form a large family of proteins that mediate voltage-dependent transport of Cl- ions across cell membranes. They are expressed in both plasma and intracellular membranes of cells from almost all living organisms. ClC proteins form transmembrane dimers, in which each monomer displays independent ion conductance. Eukaryotic members also possess a large cytoplasmic domain containing two CBS domains, which are involved in transport modulation. ClC proteins function as either Cl- channels or Cl-/H+ exchangers, although all ClC proteins share the same basic architecture. ClC channels have two gating mechanisms: a relatively well-studied fast gating mechanism, and a slow gating mechanism, which is poorly defined. ClCs are involved in a wide range of physiological processes, including regulation of resting membrane potential in skeletal muscle, facilitation of transepithelial Cl- reabsorption in kidneys, and control of pH and Cl- concentration in intracellular compartments through coupled Cl-/H+ exchange mechanisms. Several inherited diseases result from C1C gene mutations, including myotonia congenita, Bartter's syndrome (types 3 and 4), Dent's disease, osteopetrosis, retinal degeneration, and lysosomal storage diseases. This review summarizes general features, known or suspected, of ClC structure, gating and physiological functions. We also discuss biophysical properties of mammalian ClCs that are directly involved in the pathophysiology of several human inherited disorders, or that induce interesting phenotypes in animal models.
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Affiliation(s)
- Diogo R Poroca
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
| | - Ryan M Pelis
- Department of Pharmacology, Dalhousie University, Halifax NS, Canada
| | - Valérie M Chappe
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
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Pedersen TH, Riisager A, de Paoli FV, Chen TY, Nielsen OB. Role of physiological ClC-1 Cl- ion channel regulation for the excitability and function of working skeletal muscle. ACTA ACUST UNITED AC 2016; 147:291-308. [PMID: 27022190 PMCID: PMC4810071 DOI: 10.1085/jgp.201611582] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/07/2016] [Indexed: 12/13/2022]
Abstract
Electrical membrane properties of skeletal muscle fibers have been thoroughly studied over the last five to six decades. This has shown that muscle fibers from a wide range of species, including fish, amphibians, reptiles, birds, and mammals, are all characterized by high resting membrane permeability for Cl− ions. Thus, in resting human muscle, ClC-1 Cl− ion channels account for ∼80% of the membrane conductance, and because active Cl− transport is limited in muscle fibers, the equilibrium potential for Cl− lies close to the resting membrane potential. These conditions—high membrane conductance and passive distribution—enable ClC-1 to conduct membrane current that inhibits muscle excitability. This depressing effect of ClC-1 current on muscle excitability has mostly been associated with skeletal muscle hyperexcitability in myotonia congenita, which arises from loss-of-function mutations in the CLCN1 gene. However, given that ClC-1 must be drastically inhibited (∼80%) before myotonia develops, more recent studies have explored whether acute and more subtle ClC-1 regulation contributes to controlling the excitability of working muscle. Methods were developed to measure ClC-1 function with subsecond temporal resolution in action potential firing muscle fibers. These and other techniques have revealed that ClC-1 function is controlled by multiple cellular signals during muscle activity. Thus, onset of muscle activity triggers ClC-1 inhibition via protein kinase C, intracellular acidosis, and lactate ions. This inhibition is important for preserving excitability of working muscle in the face of activity-induced elevation of extracellular K+ and accumulating inactivation of voltage-gated sodium channels. Furthermore, during prolonged activity, a marked ClC-1 activation can develop that compromises muscle excitability. Data from ClC-1 expression systems suggest that this ClC-1 activation may arise from loss of regulation by adenosine nucleotides and/or oxidation. The present review summarizes the current knowledge of the physiological factors that control ClC-1 function in active muscle.
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Affiliation(s)
| | - Anders Riisager
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Tsung-Yu Chen
- Center for Neuroscience and Department of Neurology, University of California, Davis, Davis, CA 95618 Center for Neuroscience and Department of Neurology, University of California, Davis, Davis, CA 95618
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Tincheva S, Georgieva B, Todorov T, Savov A, Tsaneva S, Litvinenko I, Mitev V, Todorova A. Myotonia congenita type Becker in Bulgaria: First genetically proven cases and mutation screening of two presumable endemic regions. Neuromuscul Disord 2016; 26:675-680. [PMID: 27614575 DOI: 10.1016/j.nmd.2016.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 11/30/2022]
Abstract
Myotonia congenita type Becker is an autosomal recessive nondystrophic skeletal muscle disorder, caused by mutations in the CLCN1 gene. The disease is characterized by muscle stiffness and an inability of the muscle to relax after voluntary contraction. Here we report the results from molecular genetic testing of 6 families, referred for sequencing of the CLCN1 gene. The disease causing mutations were detected in 5 of the cases, representing diverse type of nucleotide changes: nonsense (p.Arg894*), splice-site (c.1471+1G>A), missense (p.Val273Met; p.Tyr524Cys). Two additional changes were detected in an asymptomatic individual (c.2284+5C>T and p.Phe167Leu). Two of the detected mutations are interesting from population point of view. The novel missense mutation p.Tyr524Cys was found in a large Bulgarian family with affected individuals in both vertical and horizontal pedigree directions, all of them carrying the mutation in homozygous form. They populate a village located in the northwest part of the country. Endogamous marriages are very unusual for the Bulgarian population, supposing a high carrier frequency in this subpopulation. Screening of 154 residents of the corresponding region showed a significant carrier frequency for the p.Tyr524Cys mutation of about 0.65% (1/154). The second interesting region in the context of Myotonia congenita type Becker is the southwest part of the country, where we found a large family of Bulgarian Turkish origin. The disease causing missense mutation p.Val273Met was again present in homozygous state. Surprisingly, the genetic testing of newborns from southwest Bulgaria showed an even higher carrier status of about 2.6% (3/116), disproving our initial hypothesis of endogamous marriages (traditionally common in this subpopulation) being the cause of the disease in these patients. However the probability of consanguineous marriages being the cause for further exaggeration of the anyway very high carrier frequency cannot be excluded.
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Affiliation(s)
- Savina Tincheva
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria; Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria.
| | - Bilyana Georgieva
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria
| | - Tihomir Todorov
- Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria
| | - Alexey Savov
- Department of Obstetrics and Gynecology, Faculty of Medicine, National Genetic Laboratory, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria
| | - Slavena Tsaneva
- Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria
| | - Ivan Litvinenko
- Department of Neurology, University Pediatric Hospital, Medical University, 11 Acad. Ivan Evstatiev Geshov Str., Sofia, Bulgaria
| | - Vanyo Mitev
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria
| | - Albena Todorova
- Department of Medical Chemistry and Biochemistry, Medical University Sofia, 2 Zdrave Str., Sofia, Bulgaria; Genetic Medico-Diagnostic Laboratory "Genica", 90 Tsar Asen Str., Sofia, Bulgaria
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Riisager A, de Paoli FV, Yu WP, Pedersen TH, Chen TY, Nielsen OB. Protein kinase C-dependent regulation of ClC-1 channels in active human muscle and its effect on fast and slow gating. J Physiol 2016; 594:3391-406. [PMID: 26857341 DOI: 10.1113/jp271556] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/26/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Regulation of ion channel function during repeated firing of action potentials is commonly observed in excitable cells. Recently it was shown that muscle activity is associated with rapid, protein kinase C (PKC)-dependent ClC-1 Cl(-) channel inhibition in rodent muscle. While this PKC-dependent ClC-1 inhibition during muscle activity was shown to be important for the maintenance of contractile endurance in rat muscle it is unknown whether a similar regulation exists in human muscle. Also, the molecular mechanisms underlying the observed PKC-dependent ClC-1 inhibition are unclear. Here we present the first demonstration of ClC-1 inhibition in active human muscle fibres, and we determine the changes in ClC-1 gating that underlie the PKC-dependent ClC-1 inhibition in active muscle using human ClC-1 expressed in Xenopus oocytes. This activity-induced ClC-1 inhibition is suggested to represent a mechanism by which human muscle fibres maintain their excitability during sustained activity. ABSTRACT Repeated firing of action potentials (APs) is known to trigger rapid, protein kinase C (PKC)-dependent inhibition of ClC-1 Cl(-) ion channels in rodent muscle and this inhibition is important for contractile endurance. It is currently unknown whether similar regulation exists in human muscle, and the molecular mechanisms underlying PKC-dependent ClC-1 inhibition are unclear. This study first determined whether PKC-dependent ClC-1 inhibition exists in active human muscle, and second, it clarified how PKC alters the gating of human ClC-1 expressed in Xenopus oocytes. In human abdominal and intercostal muscles, repeated AP firing was associated with 30-60% reduction of ClC-1 function, which could be completely prevented by PKC inhibition (1 μm GF109203X). The role of the PKC-dependent ClC-1 inhibition was evaluated from rheobase currents before and after firing 1000 APs: while rheobase current was well maintained after activity under control conditions it rose dramatically if PKC-dependent ClC-1 inhibition had been prevented with the inhibitor. This demonstrates that the ClC-1 inhibition is important for maintenance of excitability in active human muscle fibres. Oocyte experiments showed that PKC activation lowered the overall open probability of ClC-1 in the voltage range relevant for AP initiation in muscle fibres. More detailed analysis of this reduction showed that PKC mostly affected the slow gate of ClC-1. Indeed, there was no effect of PKC activation in C277S mutated ClC-1 in which the slow gate is effectively locked open. It is concluded that regulation of excitability of active human muscle fibres relies on PKC-dependent ClC-1 inhibition via a gating mechanism.
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Affiliation(s)
- Anders Riisager
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark.,Centre for Neuroscience and Department of Neurology, University of California, Davis, CA, 95618, USA
| | - Frank Vincenzo de Paoli
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark.,Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Wei-Ping Yu
- Centre for Neuroscience and Department of Neurology, University of California, Davis, CA, 95618, USA
| | - Thomas Holm Pedersen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark
| | - Tsung-Yu Chen
- Centre for Neuroscience and Department of Neurology, University of California, Davis, CA, 95618, USA
| | - Ole Baekgaard Nielsen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark
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Kostantin E, Hardy S, Valinsky WC, Kompatscher A, de Baaij JHF, Zolotarov Y, Landry M, Uetani N, Martínez-Cruz LA, Hoenderop JGJ, Shrier A, Tremblay ML. Inhibition of PRL-2·CNNM3 Protein Complex Formation Decreases Breast Cancer Proliferation and Tumor Growth. J Biol Chem 2016; 291:10716-25. [PMID: 26969161 PMCID: PMC4865918 DOI: 10.1074/jbc.m115.705863] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Indexed: 11/06/2022] Open
Abstract
The oncogenic phosphatase of regenerating liver 2 (PRL-2) has been shown to regulate intracellular magnesium levels by forming a complex through an extended amino acid loop present in the Bateman module of the CNNM3 magnesium transporter. Here we identified highly conserved residues located on this amino acid loop critical for the binding with PRL-2. A single point mutation (D426A) of one of those critical amino acids was found to completely disrupt PRL-2·human Cyclin M 3 (CNNM3) complex formation. Whole-cell voltage clamping revealed that expression of CNNM3 influenced the surface current, whereas overexpression of the binding mutant had no effect, indicating that the binding of PRL-2 to CNNM3 is important for the activity of the complex. Interestingly, overexpression of the CNNM3 D426A-binding mutant in cancer cells decreased their ability to proliferate under magnesium-deprived situations and under anchorage-independent growth conditions, demonstrating a PRL-2·CNNM3 complex-dependent oncogenic advantage in a more stringent environment. We further confirmed the importance of this complex in vivo using an orthotopic xenograft breast cancer model. Finally, because molecular modeling showed that the Asp-426 side chain in CNNM3 buries into the catalytic cavity of PRL-2, we showed that a PRL inhibitor could abrogate complex formation, resulting in a decrease in proliferation of human breast cancer cells. In summary, we provide evidence that this fundamental regulatory aspect of PRL-2 in cancer cells could potentially lead to broadly applicable and innovative therapeutic avenues.
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Affiliation(s)
- Elie Kostantin
- From the Rosalind and Morris Goodman Cancer Research Centre, Montréal, Québec H3A 1A3, Canada, the Departments of Biochemistry and
| | - Serge Hardy
- From the Rosalind and Morris Goodman Cancer Research Centre, Montréal, Québec H3A 1A3, Canada
| | | | - Andreas Kompatscher
- the Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands, and
| | - Jeroen H F de Baaij
- the Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands, and
| | - Yevgen Zolotarov
- From the Rosalind and Morris Goodman Cancer Research Centre, Montréal, Québec H3A 1A3, Canada, the Departments of Biochemistry and
| | - Melissa Landry
- From the Rosalind and Morris Goodman Cancer Research Centre, Montréal, Québec H3A 1A3, Canada
| | - Noriko Uetani
- From the Rosalind and Morris Goodman Cancer Research Centre, Montréal, Québec H3A 1A3, Canada
| | - Luis Alfonso Martínez-Cruz
- the Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain
| | - Joost G J Hoenderop
- the Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands, and
| | - Alvin Shrier
- Physiology, McGill University, Montréal, Québec H3A 0G4, Canada
| | - Michel L Tremblay
- From the Rosalind and Morris Goodman Cancer Research Centre, Montréal, Québec H3A 1A3, Canada, the Departments of Biochemistry and
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Chapter Five - Ubiquitination of Ion Channels and Transporters. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:161-223. [DOI: 10.1016/bs.pmbts.2016.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Hu H, Haas SA, Chelly J, Van Esch H, Raynaud M, de Brouwer APM, Weinert S, Froyen G, Frints SGM, Laumonnier F, Zemojtel T, Love MI, Richard H, Emde AK, Bienek M, Jensen C, Hambrock M, Fischer U, Langnick C, Feldkamp M, Wissink-Lindhout W, Lebrun N, Castelnau L, Rucci J, Montjean R, Dorseuil O, Billuart P, Stuhlmann T, Shaw M, Corbett MA, Gardner A, Willis-Owen S, Tan C, Friend KL, Belet S, van Roozendaal KEP, Jimenez-Pocquet M, Moizard MP, Ronce N, Sun R, O'Keeffe S, Chenna R, van Bömmel A, Göke J, Hackett A, Field M, Christie L, Boyle J, Haan E, Nelson J, Turner G, Baynam G, Gillessen-Kaesbach G, Müller U, Steinberger D, Budny B, Badura-Stronka M, Latos-Bieleńska A, Ousager LB, Wieacker P, Rodríguez Criado G, Bondeson ML, Annerén G, Dufke A, Cohen M, Van Maldergem L, Vincent-Delorme C, Echenne B, Simon-Bouy B, Kleefstra T, Willemsen M, Fryns JP, Devriendt K, Ullmann R, Vingron M, Wrogemann K, Wienker TF, Tzschach A, van Bokhoven H, Gecz J, Jentsch TJ, Chen W, Ropers HH, Kalscheuer VM. X-exome sequencing of 405 unresolved families identifies seven novel intellectual disability genes. Mol Psychiatry 2016; 21:133-48. [PMID: 25644381 PMCID: PMC5414091 DOI: 10.1038/mp.2014.193] [Citation(s) in RCA: 208] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 11/17/2014] [Accepted: 12/08/2014] [Indexed: 12/27/2022]
Abstract
X-linked intellectual disability (XLID) is a clinically and genetically heterogeneous disorder. During the past two decades in excess of 100 X-chromosome ID genes have been identified. Yet, a large number of families mapping to the X-chromosome remained unresolved suggesting that more XLID genes or loci are yet to be identified. Here, we have investigated 405 unresolved families with XLID. We employed massively parallel sequencing of all X-chromosome exons in the index males. The majority of these males were previously tested negative for copy number variations and for mutations in a subset of known XLID genes by Sanger sequencing. In total, 745 X-chromosomal genes were screened. After stringent filtering, a total of 1297 non-recurrent exonic variants remained for prioritization. Co-segregation analysis of potential clinically relevant changes revealed that 80 families (20%) carried pathogenic variants in established XLID genes. In 19 families, we detected likely causative protein truncating and missense variants in 7 novel and validated XLID genes (CLCN4, CNKSR2, FRMPD4, KLHL15, LAS1L, RLIM and USP27X) and potentially deleterious variants in 2 novel candidate XLID genes (CDK16 and TAF1). We show that the CLCN4 and CNKSR2 variants impair protein functions as indicated by electrophysiological studies and altered differentiation of cultured primary neurons from Clcn4(-/-) mice or after mRNA knock-down. The newly identified and candidate XLID proteins belong to pathways and networks with established roles in cognitive function and intellectual disability in particular. We suggest that systematic sequencing of all X-chromosomal genes in a cohort of patients with genetic evidence for X-chromosome locus involvement may resolve up to 58% of Fragile X-negative cases.
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Affiliation(s)
- H Hu
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - S A Haas
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - J Chelly
- University Paris Descartes, Paris, France,Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut National de la Santé et de la Recherche Médicale Unité 1016, Institut Cochin, Paris, France
| | - H Van Esch
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - M Raynaud
- Inserm U930 ‘Imaging and Brain', Tours, France,University François-Rabelais, Tours, France,Centre Hospitalier Régional Universitaire, Service de Génétique, Tours, France
| | - A P M de Brouwer
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - S Weinert
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany,Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - G Froyen
- Human Genome Laboratory, VIB Center for the Biology of Disease, Leuven, Belgium,Human Genome Laboratory, Department of Human Genetics, K.U. Leuven, Leuven, Belgium
| | - S G M Frints
- Department of Clinical Genetics, Maastricht University Medical Center, azM, Maastricht, The Netherlands,School for Oncology and Developmental Biology, GROW, Maastricht University, Maastricht, The Netherlands
| | - F Laumonnier
- Inserm U930 ‘Imaging and Brain', Tours, France,University François-Rabelais, Tours, France
| | - T Zemojtel
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - M I Love
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - H Richard
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - A-K Emde
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - M Bienek
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - C Jensen
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - M Hambrock
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - U Fischer
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - C Langnick
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - M Feldkamp
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - W Wissink-Lindhout
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - N Lebrun
- University Paris Descartes, Paris, France,Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut National de la Santé et de la Recherche Médicale Unité 1016, Institut Cochin, Paris, France
| | - L Castelnau
- University Paris Descartes, Paris, France,Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut National de la Santé et de la Recherche Médicale Unité 1016, Institut Cochin, Paris, France
| | - J Rucci
- University Paris Descartes, Paris, France,Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut National de la Santé et de la Recherche Médicale Unité 1016, Institut Cochin, Paris, France
| | - R Montjean
- University Paris Descartes, Paris, France,Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut National de la Santé et de la Recherche Médicale Unité 1016, Institut Cochin, Paris, France
| | - O Dorseuil
- University Paris Descartes, Paris, France,Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut National de la Santé et de la Recherche Médicale Unité 1016, Institut Cochin, Paris, France
| | - P Billuart
- University Paris Descartes, Paris, France,Centre National de la Recherche Scientifique Unité Mixte de Recherche 8104, Institut National de la Santé et de la Recherche Médicale Unité 1016, Institut Cochin, Paris, France
| | - T Stuhlmann
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany,Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - M Shaw
- School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia,Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
| | - M A Corbett
- School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia,Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
| | - A Gardner
- School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia,Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
| | - S Willis-Owen
- School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia,National Heart and Lung Institute, Imperial College London, London, UK
| | - C Tan
- School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia
| | - K L Friend
- SA Pathology, Women's and Children's Hospital, Adelaide, SA, Australia
| | - S Belet
- Human Genome Laboratory, VIB Center for the Biology of Disease, Leuven, Belgium,Human Genome Laboratory, Department of Human Genetics, K.U. Leuven, Leuven, Belgium
| | - K E P van Roozendaal
- Department of Clinical Genetics, Maastricht University Medical Center, azM, Maastricht, The Netherlands,School for Oncology and Developmental Biology, GROW, Maastricht University, Maastricht, The Netherlands
| | - M Jimenez-Pocquet
- Centre Hospitalier Régional Universitaire, Service de Génétique, Tours, France
| | - M-P Moizard
- Inserm U930 ‘Imaging and Brain', Tours, France,University François-Rabelais, Tours, France,Centre Hospitalier Régional Universitaire, Service de Génétique, Tours, France
| | - N Ronce
- Inserm U930 ‘Imaging and Brain', Tours, France,University François-Rabelais, Tours, France,Centre Hospitalier Régional Universitaire, Service de Génétique, Tours, France
| | - R Sun
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - S O'Keeffe
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - R Chenna
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - A van Bömmel
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - J Göke
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - A Hackett
- Genetics of Learning and Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - M Field
- Genetics of Learning and Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - L Christie
- Genetics of Learning and Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - J Boyle
- Genetics of Learning and Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - E Haan
- School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia,SA Pathology, Women's and Children's Hospital, Adelaide, SA, Australia
| | - J Nelson
- Genetic Services of Western Australia, King Edward Memorial Hospital, Perth, WA, Australia
| | - G Turner
- Genetics of Learning and Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - G Baynam
- Genetic Services of Western Australia, King Edward Memorial Hospital, Perth, WA, Australia,School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia,Institute for Immunology and Infectious Diseases, Murdoch University, Perth, WA, Australia,Telethon Kids Institute, Perth, WA, Australia
| | | | - U Müller
- Institut für Humangenetik, Justus-Liebig-Universität Giessen, Giessen, Germany,bio.logis Center for Human Genetics, Frankfurt a. M., Germany
| | - D Steinberger
- Institut für Humangenetik, Justus-Liebig-Universität Giessen, Giessen, Germany,bio.logis Center for Human Genetics, Frankfurt a. M., Germany
| | - B Budny
- Chair and Department of Endocrinology, Metabolism and Internal Diseases, Ponzan University of Medical Sciences, Poznan, Poland
| | - M Badura-Stronka
- Chair and Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - A Latos-Bieleńska
- Chair and Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - L B Ousager
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - P Wieacker
- Institut für Humangenetik, Universitätsklinikum Münster, Muenster, Germany
| | | | - M-L Bondeson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - G Annerén
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - A Dufke
- Institut für Medizinische Genetik und Angewandte Genomik, Tübingen, Germany
| | - M Cohen
- Kinderzentrum München, München, Germany
| | - L Van Maldergem
- Centre de Génétique Humaine, Université de Franche-Comté, Besançon, France
| | - C Vincent-Delorme
- Service de Génétique, Hôpital Jeanne de Flandre CHRU de Lilles, Lille, France
| | - B Echenne
- Service de Neuro-Pédiatrie, CHU Montpellier, Montpellier, France
| | - B Simon-Bouy
- Laboratoire SESEP, Centre hospitalier de Versailles, Le Chesnay, France
| | - T Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - M Willemsen
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - J-P Fryns
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - K Devriendt
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - R Ullmann
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - M Vingron
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - K Wrogemann
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany,Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada
| | - T F Wienker
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - A Tzschach
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - H van Bokhoven
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - J Gecz
- School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia,Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
| | - T J Jentsch
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany,Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - W Chen
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany,Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - H-H Ropers
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - V M Kalscheuer
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany,Max Planck Institute for Molecular Genetics, Ihnestrasse 73, Berlin 14195, Germany. E-mail:
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Vindas-Smith R, Fiore M, Vásquez M, Cuenca P, del Valle G, Lagostena L, Gaitán-Peñas H, Estevez R, Pusch M, Morales F. Identification and Functional Characterization ofCLCN1Mutations Found in Nondystrophic Myotonia Patients. Hum Mutat 2015; 37:74-83. [DOI: 10.1002/humu.22916] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 09/25/2015] [Indexed: 10/22/2022]
Affiliation(s)
- Rebeca Vindas-Smith
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
| | - Michele Fiore
- Istituto di Biofisica; CNR; Via De Marini 6 Genova Italy
| | - Melissa Vásquez
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
| | - Patricia Cuenca
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
- Escuela de Medicina; Universidad de Costa Rica; Curridabat San José Costa Rica
| | - Gerardo del Valle
- Laboratorio de Neurofisiología (Neurolab); Curridabat San José Costa Rica
| | | | - Héctor Gaitán-Peñas
- Departament de Ciències Fisiològiques II; Unitat de Fisiologia; Universitat de Barcelona; Carrer Feixa Llarga s/n, L'Hospitalet de Llobregat Barcelona Spain
- U-750, Centro de Investigación en red de enfermedades raras (CIBERER); ISCIII; Barcelona Spain
| | - Raúl Estevez
- Departament de Ciències Fisiològiques II; Unitat de Fisiologia; Universitat de Barcelona; Carrer Feixa Llarga s/n, L'Hospitalet de Llobregat Barcelona Spain
- U-750, Centro de Investigación en red de enfermedades raras (CIBERER); ISCIII; Barcelona Spain
| | - Michael Pusch
- Istituto di Biofisica; CNR; Via De Marini 6 Genova Italy
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
- Escuela de Medicina; Universidad de Costa Rica; Curridabat San José Costa Rica
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Jeworutzki E, Lagostena L, Elorza-Vidal X, López-Hernández T, Estévez R, Pusch M. GlialCAM, a CLC-2 Cl(-) channel subunit, activates the slow gate of CLC chloride channels. Biophys J 2015; 107:1105-1116. [PMID: 25185546 PMCID: PMC4156679 DOI: 10.1016/j.bpj.2014.07.040] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 07/18/2014] [Accepted: 07/25/2014] [Indexed: 01/17/2023] Open
Abstract
GlialCAM, a glial cell adhesion molecule mutated in megalencephalic leukoencephalopathy with subcortical cysts, targets the CLC-2 Cl(-) channel to cell contacts in glia and activates CLC-2 currents in vitro and in vivo. We found that GlialCAM clusters all CLC channels at cell contacts in vitro and thus studied GlialCAM interaction with CLC channels to investigate the mechanism of functional activation. GlialCAM slowed deactivation kinetics of CLC-Ka/barttin channels and increased CLC-0 currents opening the common gate and slowing its deactivation. No functional effect was seen for common gate deficient CLC-0 mutants. Similarly, GlialCAM targets the common gate deficient CLC-2 mutant E211V/H816A to cell contacts, without altering its function. Thus, GlialCAM is able to interact with all CLC channels tested, targeting them to cell junctions and activating them by stabilizing the open configuration of the common gate. These results are important to better understand the physiological role of GlialCAM/CLC-2 interaction.
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Affiliation(s)
- Elena Jeworutzki
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy; Departments of Anesthesia and Biomedizin, ZLF Lab 408, Universitätsspital Basel, Switzerland
| | - Laura Lagostena
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy
| | - Xabier Elorza-Vidal
- Physiology Section, Department of Physiological Sciences II, School of Medicine, Barcelona, Spain; U-750, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Tania López-Hernández
- Physiology Section, Department of Physiological Sciences II, School of Medicine, Barcelona, Spain; U-750, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain; Department of Molecular Pharmacology and Cell Biology, FMP, Berlin, Germany
| | - Raúl Estévez
- Physiology Section, Department of Physiological Sciences II, School of Medicine, Barcelona, Spain; U-750, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy.
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Jentsch TJ. Discovery of CLC transport proteins: cloning, structure, function and pathophysiology. J Physiol 2015; 593:4091-109. [PMID: 25590607 DOI: 10.1113/jp270043] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/11/2015] [Indexed: 02/06/2023] Open
Abstract
After providing a personal description of the convoluted path leading 25 years ago to the molecular identification of the Torpedo Cl(-) channel ClC-0 and the discovery of the CLC gene family, I succinctly describe the general structural and functional features of these ion transporters before giving a short overview of mammalian CLCs. These can be categorized into plasma membrane Cl(-) channels and vesicular Cl(-) /H(+) -exchangers. They are involved in the regulation of membrane excitability, transepithelial transport, extracellular ion homeostasis, endocytosis and lysosomal function. Diseases caused by CLC dysfunction include myotonia, neurodegeneration, deafness, blindness, leukodystrophy, male infertility, renal salt loss, kidney stones and osteopetrosis, revealing a surprisingly broad spectrum of biological roles for chloride transport that was unsuspected when I set out to clone the first voltage-gated chloride channel.
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Affiliation(s)
- Thomas J Jentsch
- Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
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34
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Accardi A. Structure and gating of CLC channels and exchangers. J Physiol 2015; 593:4129-38. [PMID: 26148215 DOI: 10.1113/jp270575] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 06/28/2015] [Indexed: 11/08/2022] Open
Abstract
Since their serendipitous discovery the CLC family of Cl(-) transporting proteins has been a never ending source of surprises. From their double-barrelled architecture to their complex structure and divergence as channels and transporters, the CLCs never cease to amaze biophysicists, biochemists and physiologists alike. These unusual functional properties allow the CLCs to fill diverse physiological niches, regulating processes that range from muscle contraction to acidification of intracellular organelles, nutrient accumulation and survival of bacteria to environmental stresses. Over the last 15 years, the availability of atomic-level information on the structure of the CLCs, coupled to the discovery that the family is divided into passive channels and secondary active transporters, has revolutionized our understanding of their function. These breakthroughs led to the identification of the key structural elements regulating gating, transport, selectivity and regulation by ligands. Unexpectedly, many lines of evidence indicate that the CLC exchangers function according to a non-conventional transport mechanism that defies the fundamental tenets of the alternating-access paradigm for exchange transport, paving the way for future unexpected insights into the principles underlying active transport and channel gating.
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Affiliation(s)
- Alessio Accardi
- Departments of Anaesthesiology, Physiology & Biophysics, and Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY, 10021, USA
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35
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Imbrici P, Maggi L, Mangiatordi GF, Dinardo MM, Altamura C, Brugnoni R, Alberga D, Pinter GL, Ricci G, Siciliano G, Micheli R, Annicchiarico G, Lattanzi G, Nicolotti O, Morandi L, Bernasconi P, Desaphy JF, Mantegazza R, Camerino DC. ClC-1 mutations in myotonia congenita patients: insights into molecular gating mechanisms and genotype-phenotype correlation. J Physiol 2015; 593:4181-99. [PMID: 26096614 DOI: 10.1113/jp270358] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 06/04/2015] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Loss-of-function mutations of the skeletal muscle ClC-1 channel cause myotonia congenita with variable phenotypes. Using patch clamp we show that F484L, located in the conducting pore, probably induces mild dominant myotonia by right-shifting the slow gating of ClC-1 channel, without exerting a dominant-negative effect on the wild-type (WT) subunit. Molecular dynamics simulations suggest that F484L affects the slow gate by increasing the frequency and the stability of H-bond formation between E232 in helix F and Y578 in helix R. Three other myotonic ClC-1 mutations are shown to produce distinct effects on channel function: L198P shifts the slow gate to positive potentials, V640G reduces channel activity, while L628P displays a WT-like behaviour (electrophysiology data only). Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function. ABSTRACT Myotonia congenita is an inherited disease caused by loss-of-function mutations of the skeletal muscle ClC-1 chloride channel, characterized by impaired muscle relaxation after contraction and stiffness. In the present study, we provided an in-depth characterization of F484L, a mutation previously identified in dominant myotonia, in order to define the genotype-phenotype correlation, and to elucidate the contribution of this pore residue to the mechanisms of ClC-1 gating. Patch-clamp recordings showed that F484L reduced chloride currents at every tested potential and dramatically right-shifted the voltage dependence of slow gating, thus contributing to the mild clinical phenotype of affected heterozygote carriers. Unlike dominant mutations located at the dimer interface, no dominant-negative effect was observed when F484L mutant subunits were co-expressed with wild type. Molecular dynamics simulations further revealed that F484L affected the slow gate by increasing the frequency and stability of the H-bond formation between the pore residue E232 and the R helix residue Y578. In addition, using patch-clamp electrophysiology, we characterized three other myotonic ClC-1 mutations. We proved that the dominant L198P mutation in the channel pore also right-shifted the voltage dependence of slow gating, recapitulating mild myotonia. The recessive V640G mutant drastically reduced channel function, which probably accounts for myotonia. In contrast, the recessive L628P mutant produced currents very similar to wild type, suggesting that the occurrence of the compound truncating mutation (Q812X) or other muscle-specific mechanisms accounted for the severe symptoms observed in this family. Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function.
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Affiliation(s)
- P Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - L Maggi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - G F Mangiatordi
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - M M Dinardo
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - C Altamura
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - R Brugnoni
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - D Alberga
- Department of Physics 'M. Merlin', INFN and TIRES, University of Bari, Bari, Italy
| | - G Lauria Pinter
- Neuroalgology and Headache Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - G Ricci
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - G Siciliano
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - R Micheli
- Unit of Child Neurology and Psychiatry, Spedali Civili, Brescia, Italy
| | - G Annicchiarico
- Regional Coordination for Rare Diseases, A. Re. S. Puglia, Bari, Italy
| | - G Lattanzi
- Department of Physics 'M. Merlin', INFN and TIRES, University of Bari, Bari, Italy
| | - O Nicolotti
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - L Morandi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - P Bernasconi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - J-F Desaphy
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - R Mantegazza
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - D Conte Camerino
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
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Andrini O, Keck M, Briones R, Lourdel S, Vargas-Poussou R, Teulon J. ClC-K chloride channels: emerging pathophysiology of Bartter syndrome type 3. Am J Physiol Renal Physiol 2015; 308:F1324-34. [DOI: 10.1152/ajprenal.00004.2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/23/2015] [Indexed: 02/08/2023] Open
Abstract
The mutations in the CLCNKB gene encoding the ClC-Kb chloride channel are responsible for Bartter syndrome type 3, one of the four variants of Bartter syndrome in the genetically based nomenclature. All forms of Bartter syndrome are characterized by hypokalemia, metabolic alkalosis, and secondary hyperaldosteronism, but Bartter syndrome type 3 has the most heterogeneous presentation, extending from severe to very mild. A relatively large number of CLCNKB mutations have been reported, including gene deletions and nonsense or missense mutations. However, only 20 CLCNKB mutations have been functionally analyzed, due to technical difficulties regarding ClC-Kb functional expression in heterologous systems. This review provides an overview of recent progress in the functional consequences of CLCNKB mutations on ClC-Kb chloride channel activity. It has been observed that 1) all ClC-Kb mutants have an impaired expression at the membrane; and 2) a minority of the mutants combines reduced membrane expression with altered pH-dependent channel gating. Although further investigation is needed to fully characterize disease pathogenesis, Bartter syndrome type 3 probably belongs to the large family of conformational diseases, in which the mutations destabilize channel structure, inducing ClC-Kb retention in the endoplasmic reticulum and accelerated channel degradation.
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Affiliation(s)
- Olga Andrini
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
| | - Mathilde Keck
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
| | - Rodolfo Briones
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stéphane Lourdel
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
| | - Rosa Vargas-Poussou
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Département de Génétique, Paris, France; and
- Université Paris-Descartes, Faculté de Médecine, Paris, France
| | - Jacques Teulon
- UPMC Université Paris 06, UMR_S 1138, Team 3, Paris, France
- INSERM, UMR_S 872, Paris, France
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Imbrici P, Altamura C, Pessia M, Mantegazza R, Desaphy JF, Camerino DC. ClC-1 chloride channels: state-of-the-art research and future challenges. Front Cell Neurosci 2015; 9:156. [PMID: 25964741 PMCID: PMC4410605 DOI: 10.3389/fncel.2015.00156] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/08/2015] [Indexed: 01/06/2023] Open
Abstract
The voltage-dependent ClC-1 chloride channel belongs to the CLC channel/transporter family. It is a homodimer comprising two individual pores which can operate independently or simultaneously according to two gating modes, the fast and the slow gate of the channel. ClC-1 is preferentially expressed in the skeletal muscle fibers where the presence of an efficient Cl(-) homeostasis is crucial for the correct membrane repolarization and propagation of action potential. As a consequence, mutations in the CLCN1 gene cause dominant and recessive forms of myotonia congenita (MC), a rare skeletal muscle channelopathy caused by abnormal membrane excitation, and clinically characterized by muscle stiffness and various degrees of transitory weakness. Elucidation of the mechanistic link between the genetic defects and the disease pathogenesis is still incomplete and, at this time, there is no specific treatment for MC. Still controversial is the subcellular localization pattern of ClC-1 channels in skeletal muscle as well as its modulation by some intracellular factors. The expression of ClC-1 in other tissues such as in brain and heart and the possible assembly of ClC-1/ClC-2 heterodimers further expand the physiological properties of ClC-1 and its involvement in diseases. A recent de novo CLCN1 truncation mutation in a patient with generalized epilepsy indeed postulates an unexpected role of this channel in the control of neuronal network excitability. This review summarizes the most relevant and state-of-the-art research on ClC-1 chloride channels physiology and associated diseases.
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Affiliation(s)
- Paola Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Concetta Altamura
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Mauro Pessia
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Renato Mantegazza
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | | | - Diana Conte Camerino
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
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Stölting G, Fischer M, Fahlke C. CLC channel function and dysfunction in health and disease. Front Physiol 2014; 5:378. [PMID: 25339907 PMCID: PMC4188032 DOI: 10.3389/fphys.2014.00378] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/12/2014] [Indexed: 01/01/2023] Open
Abstract
CLC channels and transporters are expressed in most tissues and fulfill diverse functions. There are four human CLC channels, ClC-1, ClC-2, ClC-Ka, and ClC-Kb, and five CLC transporters, ClC-3 through −7. Some of the CLC channels additionally associate with accessory subunits. Whereas barttin is mandatory for the functional expression of ClC-K, GlialCam is a facultative subunit of ClC-2 which modifies gating and thus increases the functional variability within the CLC family. Isoform-specific ion conduction and gating properties optimize distinct CLC channels for their cellular tasks. ClC-1 preferentially conducts at negative voltages, and the resulting inward rectification provides a large resting chloride conductance without interference with the muscle action potential. Exclusive opening at voltages negative to the chloride reversal potential allows for ClC-2 to regulate intracellular chloride concentrations. ClC-Ka and ClC-Kb are equally suited for inward and outward currents to support transcellular chloride fluxes. Every human CLC channel gene has been linked to a genetic disease, and studying these mutations has provided much information about the physiological roles and the molecular basis of CLC channel function. Mutations in the gene encoding ClC-1 cause myotonia congenita, a disease characterized by sarcolemmal hyperexcitability and muscle stiffness. Loss-of-function of ClC-Kb/barttin channels impairs NaCl resorption in the limb of Henle and causes hyponatriaemia, hypovolemia and hypotension in patients suffering from Bartter syndrome. Mutations in CLCN2 were found in patients with CNS disorders but the functional role of this isoform is still not understood. Recent links between ClC-1 and epilepsy and ClC-Ka and heart failure suggested novel cellular functions of these proteins. This review aims to survey the knowledge about physiological and pathophysiological functions of human CLC channels in the light of recent discoveries from biophysical, physiological, and genetic studies.
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Affiliation(s)
- Gabriel Stölting
- Institute of Complex Systems-Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich Jülich, Germany
| | - Martin Fischer
- Institut für Neurophysiologie, Medizinische Hochschule Hannover Hannover, Germany
| | - Christoph Fahlke
- Institute of Complex Systems-Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich Jülich, Germany
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Paroxysmal kinesigenic dyskinesia and myotonia congenita in the same family: coexistence of a PRRT2 mutation and two CLCN1 mutations. Neurosci Bull 2014; 30:1010-1016. [PMID: 25205014 DOI: 10.1007/s12264-014-1467-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 04/28/2014] [Indexed: 10/24/2022] Open
Abstract
Paroxysmal kinesigenic dyskinesia (PKD) and myotonia congenita (MC) are independent disorders that share some clinical features. We aimed to investigate the sequences of PRRT2 and CLCN1 in a proband diagnosed with PKD and suspected MC. Clinical evaluation and auxiliary examinations were performed. Direct sequencing of the entire coding regions of the PRRT2 and CLCN1 genes was conducted. Haplotype analysis confirmed the relationships among the family members. The proband suffered choreoathetosis attacks triggered by sudden movements, and lower-limb weakness and stiffness that worsened in cold weather. Carbamazepine monotherapy completely controlled his choreoathetosis and significantly relieved his limb weakness and stiffness. His father, when young, had similar limb stiffness, while his mother and brother were asymptomatic. Genetic analysis revealed that the proband and his father harbored a PRRT2 c.649dupC mutation, and CLCN1 c.1723C>T and c.2492A>G mutations. His brother carried only the two CLCN1 mutations. None of these mutations were identified in his mother and 150 unrelated controls. This is the first report showing the coexistence of PRRT2 and CLCN1 mutations. Our results also indicate that both the PRRT2 and CLCN1 genes need to be screened if we fail to identify PRRT2 mutations in PKD patients or CLCN1 mutations in MC patients.
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Coffey BM, Akhand SS, Anderson GG. MgtE is a dual-function protein in Pseudomonas aeruginosa. MICROBIOLOGY-SGM 2014; 160:1200-1213. [PMID: 24722909 DOI: 10.1099/mic.0.075275-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa causes a wide range of infections, including chronic biofilm infections in the lungs of individuals with cystic fibrosis. We previously found that the inner-membrane protein MgtE can function both as a magnesium transporter and a virulence modulator, although the exact mechanism governing these activities is unclear. To address this issue, we carried out an experimental characterization of P. aeruginosa MgtE and generated a computer-rendered model. Our in silico analysis demonstrated the structural similarity of P. aeruginosa MgtE to that of the crystal structure of MgtE in Thermus thermophilus. Experimentally, we verified that MgtE is not essential for growth and found that it may not be involved directly in biofilm formation, even under low-magnesium conditions. We demonstrated both magnesium transport and cytotoxicity-regulating functions, and showed that magnesium-binding sites in the connecting helix region of MgtE are vital in coupling these two functions. Furthermore, limiting magnesium environments stimulated mgtE transcriptional responses. Our results suggested that MgtE might play an important role in linking magnesium availability to P. aeruginosa pathogenesis.
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Affiliation(s)
- Barbara M Coffey
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Saeed S Akhand
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Gregory G Anderson
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
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Pusch M, Zifarelli G. Thermal sensitivity of CLC and TMEM16 chloride channels and transporters. CURRENT TOPICS IN MEMBRANES 2014; 74:213-31. [PMID: 25366238 DOI: 10.1016/b978-0-12-800181-3.00008-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cl(-) transport is of fundamental importance in the most diverse physiological contexts and it is mediated by a variety of ion channels and transporters belonging to different protein families. In particular, the recently identified TMEM16 protein family comprises the long sought Ca(2+)-activated Cl(-) channel (CaCC) and the activity of one of its members, TMEM16A, is highly dependent on temperature and is involved in thermal nociception. Among the other protein families mediating Cl(-) transport, CLC proteins are also regulated by temperature although so far the physiological implications of this dependence are unknown.
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42
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Stauber T, Weinert S, Jentsch TJ. Cell biology and physiology of CLC chloride channels and transporters. Compr Physiol 2013; 2:1701-44. [PMID: 23723021 DOI: 10.1002/cphy.c110038] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Proteins of the CLC gene family assemble to homo- or sometimes heterodimers and either function as Cl(-) channels or as Cl(-)/H(+)-exchangers. CLC proteins are present in all phyla. Detailed structural information is available from crystal structures of bacterial and algal CLCs. Mammals express nine CLC genes, four of which encode Cl(-) channels and five 2Cl(-)/H(+)-exchangers. Two accessory β-subunits are known: (1) barttin and (2) Ostm1. ClC-Ka and ClC-Kb Cl(-) channels need barttin, whereas Ostm1 is required for the function of the lysosomal ClC-7 2Cl(-)/H(+)-exchanger. ClC-1, -2, -Ka and -Kb Cl(-) channels reside in the plasma membrane and function in the control of electrical excitability of muscles or neurons, in extra- and intracellular ion homeostasis, and in transepithelial transport. The mainly endosomal/lysosomal Cl(-)/H(+)-exchangers ClC-3 to ClC-7 may facilitate vesicular acidification by shunting currents of proton pumps and increase vesicular Cl(-) concentration. ClC-3 is also present on synaptic vesicles, whereas ClC-4 and -5 can reach the plasma membrane to some extent. ClC-7/Ostm1 is coinserted with the vesicular H(+)-ATPase into the acid-secreting ruffled border membrane of osteoclasts. Mice or humans lacking ClC-7 or Ostm1 display osteopetrosis and lysosomal storage disease. Disruption of the endosomal ClC-5 Cl(-)/H(+)-exchanger leads to proteinuria and Dent's disease. Mouse models in which ClC-5 or ClC-7 is converted to uncoupled Cl(-) conductors suggest an important role of vesicular Cl(-) accumulation in these pathologies. The important functions of CLC Cl(-) channels were also revealed by human diseases and mouse models, with phenotypes including myotonia, renal loss of salt and water, deafness, blindness, leukodystrophy, and male infertility.
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Affiliation(s)
- Tobias Stauber
- Leibniz-Institut für Molekulare Pharmakologie FMP and Max-Delbrück-Centrum für Molekulare Medizin MDC, Berlin, Germany
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Molecular determinants of common gating of a ClC chloride channel. Nat Commun 2013; 4:2507. [DOI: 10.1038/ncomms3507] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 08/27/2013] [Indexed: 11/08/2022] Open
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Ludwig CF, Ullrich F, Leisle L, Stauber T, Jentsch TJ. Common gating of both CLC transporter subunits underlies voltage-dependent activation of the 2Cl-/1H+ exchanger ClC-7/Ostm1. J Biol Chem 2013; 288:28611-9. [PMID: 23983121 DOI: 10.1074/jbc.m113.509364] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
CLC anion transporters form dimers that function either as Cl(-) channels or as electrogenic Cl(-)/H(+) exchangers. CLC channels display two different types of "gates," "protopore" gates that open and close the two pores of a CLC dimer independently of each other and common gates that act on both pores simultaneously. ClC-7/Ostm1 is a lysosomal 2Cl(-)/1H(+) exchanger that is slowly activated by depolarization. This gating process is drastically accelerated by many CLCN7 mutations underlying human osteopetrosis. Making use of some of these mutants, we now investigate whether slow voltage activation of plasma membrane-targeted ClC-7/Ostm1 involves protopore or common gates. Voltage activation of wild-type ClC-7 subunits was accelerated by co-expressing an excess of ClC-7 subunits carrying an accelerating mutation together with a point mutation rendering these subunits transport-deficient. Conversely, voltage activation of a fast ClC-7 mutant could be slowed by co-expressing an excess of a transport-deficient mutant. These effects did not depend on whether the accelerating mutation localized to the transmembrane part or to cytoplasmic cystathionine-β-synthase (CBS) domains of ClC-7. Combining accelerating mutations in the same subunit did not speed up gating further. No currents were observed when ClC-7 was truncated after the last intramembrane helix. Currents and slow gating were restored when the C terminus was co-expressed by itself or fused to the C terminus of the β-subunit Ostm1. We conclude that common gating underlies the slow voltage activation of ClC-7. It depends on the CBS domain-containing C terminus that does not require covalent binding to the membrane domain of ClC-7.
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Affiliation(s)
- Carmen F Ludwig
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and
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45
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Functional characterization of ClC-1 mutations from patients affected by recessive myotonia congenita presenting with different clinical phenotypes. Exp Neurol 2013; 248:530-40. [PMID: 23933576 PMCID: PMC3781327 DOI: 10.1016/j.expneurol.2013.07.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 07/18/2013] [Accepted: 07/25/2013] [Indexed: 12/03/2022]
Abstract
Myotonia congenita (MC) is caused by loss-of-function mutations of the muscle ClC-1 chloride channel. Clinical manifestations include the variable association of myotonia and transitory weakness. We recently described a cohort of recessive MC patients showing, at a low rate repetitive nerves stimulation protocol, different values of compound muscle action potential (CMAP) transitory depression, which is considered the neurophysiologic counterpart of transitory weakness. From among this cohort, we studied the chloride currents generated by G190S (associated with pronounced transitory depression), F167L (little or no transitory depression), and A531V (variable transitory depression) hClC-1 mutants in transfected HEK293 cells using patch-clamp. While F167L had no effect on chloride currents, G190S dramatically shifts the voltage dependence of channel activation and A531V reduces channel expression. Such variability in molecular mechanisms observed in the hClC-1 mutants may help to explain the different clinical and neurophysiologic manifestations of each ClCN1 mutation. In addition we examined five different mutations found in compound heterozygosis with F167L, including the novel P558S, and we identified additional molecular defects. Finally, the G190S mutation appeared to impair acetazolamide effects on chloride currents in vitro. Myotonia congenita is a muscle disorder due to mutations in ClC-1 chloride channel. Eight ClC-1 channel mutants were studied using patch-clamp technique. Mutations induce a variety of molecular defects in ClC-1 channel function. We discuss the relationship between genotype and clinical phenotype.
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Bossus M, Charmantier G, Blondeau-Bidet E, Valletta B, Boulo V, Lorin-Nebel C. The ClC-3 chloride channel and osmoregulation in the European sea bass, Dicentrarchus labrax. J Comp Physiol B 2013; 183:641-62. [PMID: 23292336 DOI: 10.1007/s00360-012-0737-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/27/2012] [Accepted: 11/23/2012] [Indexed: 11/29/2022]
Abstract
Dicentrarchus labrax migrates between sea (SW), brackish and fresh water (FW) where chloride concentrations and requirements for chloride handling change: in FW, fish absorb chloride and restrict renal losses; in SW, they excrete chloride. In this study, the expression and localization of ClC-3 and Na(+)/K(+)-ATPase (NKA) were studied in fish adapted to SW, or exposed to FW from 10 min to 30 days. In gills, NKA-α1 subunit expression transiently increased from 10 min and reached a stabilized intermediate expression level after 24 h in FW. ClC-3 co-localized with NKA in the basolateral membrane of mitochondria-rich cells (MRCs) at all conditions. The intensity of MRC ClC-3 immunostaining was significantly higher (by 50 %) 1 h after the transfer to FW, whereas the branchial ClC-3 protein expression was 30 % higher 7 days after the transfer as compared to SW. This is consistent with the increased number of immunopositive MRCs (immunostained for NKA and ClC-3). However, the ClC-3 mRNA expression was significantly lower in FW gills. In the kidney, after FW transfer, a transient decrease in NKA-α1 subunit expression was followed by significantly higher stable levels from 24 h. The low ClC-3 protein expression detected at both salinities was not observed by immunocytochemistry in the SW kidney; ClC-3 was localized in the basal membrane of the collecting ducts and tubules 7 and 30 days after transfer to FW. Renal ClC-3 mRNA expression, however, seemed higher in SW than in FW. The potential role of this chloride channel ClC-3 in osmoregulatory and osmosensing mechanisms is discussed.
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Affiliation(s)
- Maryline Bossus
- Equipe Adaptation Ecophysiologique et Ontogenèse, UMR5119 - EcoSyM, UM2-UM1-CNRS-IRD-IFREMER, cc 092, Place E. Bataillon, 34095 Montpellier cedex 05, France.
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A large cohort of myotonia congenita probands: novel mutations and a high-frequency mutation region in exons 4 and 5 of the CLCN1 gene. J Hum Genet 2013; 58:581-7. [DOI: 10.1038/jhg.2013.58] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 04/30/2013] [Accepted: 05/01/2013] [Indexed: 11/08/2022]
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48
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Zhang Q, Hou M, Li Q, Han L, Yuan Z, Tan J, Du B, Zou X, Hou L. Expression patterns of As-ClC gene of Artemia sinica in early development and under salinity stress. Mol Biol Rep 2013; 40:3655-64. [PMID: 23277400 DOI: 10.1007/s11033-012-2441-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 12/18/2012] [Indexed: 01/05/2023]
Abstract
As-ClC (chloride channels protein from Artemia sinica), a member from the chloride channels protein family, is a α-helical membrane protein predicted to traverse the cell membrane 11 times. It is important for several physiological functions such as cell volume regulation, cell proliferation, growth and differentiation. In this paper, the complete cDNA sequence of As-CIC was cloned from A. sinica for the first time using RACE technology. The expression pattern and location of the As-CIC gene was investigated in different stages of the embryonic development by means of quantitative real-time PCR and in situ hybridization (ISH) assay. As-CLC was distributed throughout the whole body in cells of different embryonic development of A. sinica as shown by ISH. There was a low expression level of the As-ClC gene after 0 h and a higher expression level after 15 and 40 h when the embryo entered the next growth period and the environmental salinity changed. At adult stage, the As-ClC maintained a high expression level. The results of the real-time PCR assay showed an increasing trend of As-ClC transcripts with increasing salinity. The expression of As-ClC was higher in the control group (28) than in the experimental group except at a salinity of 200 PSU. It indicated that As-ClC functions as salinity-stress-related gene, probably participated in cell volume regulation and osmotic regulation during the early embryonic development of A. sinica.
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Affiliation(s)
- Qiaozhi Zhang
- College of Life Sciences, Liaoning Normal University, Dalian 116029, People's Republic of China
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Miyazaki H, Yamada T, Parton A, Morrison R, Kim S, Beth AH, Strange K. CLC anion channel regulatory phosphorylation and conserved signal transduction domains. Biophys J 2012; 103:1706-18. [PMID: 23083714 DOI: 10.1016/j.bpj.2012.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/20/2012] [Accepted: 09/04/2012] [Indexed: 12/01/2022] Open
Abstract
The signaling mechanisms that regulate CLC anion channels are poorly understood. Caenorhabditis elegans CLH-3b is a member of the CLC-1/2/Ka/Kb channel subfamily. CLH-3b is activated by meiotic cell-cycle progression and cell swelling. Inhibition is brought about by GCK-3 kinase-mediated phosphorylation of S742 and S747 located on a ∼176 amino acid disordered domain linking CBS1 and CBS2. Much of the inter-CBS linker is dispensable for channel regulation. However, deletion of a 14 amino acid activation domain encompassing S742 and S747 inhibits channel activity to the same extent as GCK-3. The crystal structure of CmCLC demonstrated that CBS2 interfaces extensively with an intracellular loop connecting membrane helices H and I, the C-terminus of helix D, and a short linker connecting helix R to CBS1. Point mutagenesis of this interface identified two highly conserved aromatic amino acid residues located in the H-I loop and the first α-helix (α1) of CBS2. Mutation of either residue to alanine rendered CLH-3b insensitive to GCK-3 inhibition. We suggest that the dephosphorylated activation domain normally interacts with CBS1 and/or CBS2, and that conformational information associated with this interaction is transduced through a conserved signal transduction module comprising the H-I loop and CBS2 α1.
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Affiliation(s)
- Hiroaki Miyazaki
- Boylan Center for Cellular and Molecular Physiology, Mount Desert Island Biological Laboratory, Salisbury Cove, Maine, USA
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50
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Raja Rayan DL, Haworth A, Sud R, Matthews E, Fialho D, Burge J, Portaro S, Schorge S, Tuin K, Lunt P, McEntagart M, Toscano A, Davis MB, Hanna MG. A new explanation for recessive myotonia congenita: exon deletions and duplications in CLCN1. Neurology 2012; 78:1953-8. [PMID: 22649220 DOI: 10.1212/wnl.0b013e318259e19c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE To assess whether exon deletions or duplications in CLCN1 are associated with recessive myotonia congenita (MC). METHODS We performed detailed clinical and electrophysiologic characterization in 60 patients with phenotypes consistent with MC. DNA sequencing of CLCN1 followed by multiplex ligation-dependent probe amplification to screen for exon copy number variation was undertaken in all patients. RESULTS Exon deletions or duplications in CLCN1 were identified in 6% of patients with MC. Half had heterozygous exonic rearrangements. The other 2 patients (50%), with severe disabling infantile onset myotonia, were identified with both a homozygous mutation, Pro744Thr, which functional electrophysiology studies suggested was nonpathogenic, and a triplication/homozygous duplication involving exons 8-14, suggesting an explanation for the severe phenotype. CONCLUSIONS These data indicate that copy number variation in CLCN1 may be an important cause of recessive MC. Our observations suggest that it is important to check for exon deletions and duplications as part of the genetic analysis of patients with recessive MC, especially in patients in whom sequencing identifies no mutations or only a single recessive mutation. These results also indicate that additional, as yet unidentified, genetic mechanisms account for cases not currently explained by either CLCN1 point mutations or exonic deletions or duplications.
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Affiliation(s)
- D L Raja Rayan
- Medical Research Council Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, University College London, London, UK
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