1
|
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.
Collapse
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
| |
Collapse
|
2
|
Satoh N, Suzuki M, Nakamura M, Suzuki A, Horita S, Seki G, Moriya K. Functional coupling of V-ATPase and CLC-5. World J Nephrol 2017; 6:14-20. [PMID: 28101447 PMCID: PMC5215204 DOI: 10.5527/wjn.v6.i1.14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/04/2016] [Accepted: 11/02/2016] [Indexed: 02/06/2023] Open
Abstract
Dent’s disease is an X-linked renal tubulopathy characterized by low molecular weight proteinuria, hypercalciuria and progressive renal failure. Disease aetiology is associated with mutations in the CLCN5 gene coding for the electrogenic 2Cl-/H+ antiporter chloride channel 5 (CLC-5), which is expressed in the apical endosomes of renal proximal tubules with the vacuolar type H+-ATPase (V-ATPase). Initially identified as a member of the CLC family of Cl- channels, CLC-5 was presumed to provide Cl- shunt into the endosomal lumen to dissipate H+ accumulation by V-ATPase, thereby facilitating efficient endosomal acidification. However, recent findings showing that CLC-5 is in fact not a Cl- channel but a 2Cl-/H+ antiporter challenged this classical shunt model, leading to a renewed and intense debate on its physiological roles. Cl- accumulation via CLC-5 is predicted to play a critical role in endocytosis, as illustrated in mice carrying an artificial Cl- channel mutation E211A that developed defective endocytosis but normal endosomal acidification. Conversely, a recent functional analysis of a newly identified disease-causing Cl- channel mutation E211Q in a patient with typical Dent’s disease confirmed the functional coupling between V-ATPase and CLC-5 in endosomal acidification, lending support to the classical shunt model. In this editorial, we will address the current recognition of the physiological role of CLC-5 with a specific focus on the functional coupling of V-ATPase and CLC-5.
Collapse
|
3
|
Nanami M, Lazo-Fernandez Y, Pech V, Verlander JW, Agazatian D, Weinstein AM, Bao HF, Eaton DC, Wall SM. ENaC inhibition stimulates HCl secretion in the mouse cortical collecting duct. I. Stilbene-sensitive Cl- secretion. Am J Physiol Renal Physiol 2015; 309:F251-8. [PMID: 25925258 DOI: 10.1152/ajprenal.00471.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 04/27/2015] [Indexed: 11/22/2022] Open
Abstract
Inhibition of the epithelial Na(+) channel (ENaC) reduces Cl(-) absorption in cortical collecting ducts (CCDs) from aldosterone-treated rats and mice. Since ENaC does not transport Cl(-), the purpose of the present study was to explore how ENaC modulates Cl(-) absorption in mouse CCDs perfused in vitro. Therefore, we measured transepithelial Cl(-) flux and transepithelial voltage in CCDs perfused in vitro taken from mice that consumed a NaCl-replete diet alone or the diet with aldosterone administered by minipump. We observed that application of an ENaC inhibitor [benzamil (3 μM)] to the luminal fluid unmasks conductive Cl(-) secretion. During ENaC blockade, this Cl(-) secretion fell with the application of a nonselective Cl(-) channel blocker [DIDS (100 μM)] to the perfusate. While single channel recordings of intercalated cell apical membranes in split-open CCDs demonstrated a Cl(-) channel with properties that resemble the ClC family of Cl(-) channels, ClC-5 is not the primary pathway for benzamil-sensitive Cl(-) flux. In conclusion, first, in CCDs from aldosterone-treated mice, most Cl(-) absorption is benzamil sensitive, and, second, benzamil application stimulates stilbene-sensitive conductive Cl(-) secretion, which occurs through a ClC-5-independent pathway.
Collapse
Affiliation(s)
- Masayoshi Nanami
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | | | - Vladimir Pech
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Jill W Verlander
- Department of Medicine, The University of Florida, Gainesville, Florida
| | - Diana Agazatian
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York; Department of Medicine, Weill Medical College of Cornell University, Ithaca, New York; and
| | - Hui-Fang Bao
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Douglas C Eaton
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Susan M Wall
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University School of Medicine, Atlanta, Georgia;
| |
Collapse
|
4
|
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.
Collapse
Affiliation(s)
- Tobias Stauber
- Leibniz-Institut für Molekulare Pharmakologie FMP and Max-Delbrück-Centrum für Molekulare Medizin MDC, Berlin, Germany
| | | | | |
Collapse
|
5
|
Ochoa-de la Paz LD, Espino-Saldaña AE, Arellano-Ostoa R, Reyes JP, Miledi R, Martinez-Torres A. Characterization of an outward rectifying chloride current of Xenopus tropicalis oocytes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1743-53. [PMID: 23524227 DOI: 10.1016/j.bbamem.2013.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 03/08/2013] [Accepted: 03/13/2013] [Indexed: 12/19/2022]
Abstract
Here, we describe an outward rectifying current in Xenopus tropicalis oocytes that we have called xtClC-or. The current has two components; the major component is voltage activated and independent of intracellular or extracellular Ca(2+), whereas the second is a smaller component that is Ca(2+) dependent. The properties of the Ca(2+)-independent current, such as voltage dependence and outward rectification, resemble those of ClC anion channels/transporters. This current is sensitive to NPPB and NFA, insensitive to 9AC and DIDS, and showed a whole-cell conductance sequence of SCN(-)>I(-)>Br(-)>CI(-). RT-PCR revealed the expression in oocytes of ClC-2 to ClC-7, and major reductions of current amplitudes were observed when a ClC-5 antisense oligonucleotide was injected into oocytes. The Ca(2+)-dependent component was abated after injection of 10mM BAPTA or EGTA, whereas 10mMMg(2+) inhibited the current to 26±3.1%. This component was blocked by 9-AC, NFA, and NPPB, whereas DIDS did not elicit any evident effect. The ion sequence selectivity was SCN=I(-)>Br(-)>Cl(-). To try to determine the molecular identity that gives rise to this component we assessed by RT-PCR the expression of the Ca(2+)-dependent Cl(-) channel TMEM16A, which was found to be present in the oocytes. However, injection of antisense TMEM16A oligonucleotides did not inhibit the transient outward current. This result fits well with the electrophysiological data. Together, these results suggest that ClC-5 is a major, but not the sole channel responsible for this outwardly rectifying Cl(-) current.
Collapse
Affiliation(s)
- Lenin David Ochoa-de la Paz
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM Juriquilla, Mexico
| | | | | | | | | | | |
Collapse
|
6
|
Carr G, Sayer JA, Simmons NL. Expression and Localisation of the Pyrophosphate Transporter, ANK, in Murine Kidney Cells. Cell Physiol Biochem 2008; 20:507-16. [PMID: 17762177 DOI: 10.1159/000107534] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Mutation of the pyrophosphate transporter, ANK, results in progressive arthritis in mice. ANK is expressed in non-skeletal tissues including kidney. The aim was therefore to investigate ANK location at the cellular and subcellular level in renal cells. METHODS RT-PCR identified a murine cell-line, mIMCD3, expressing ANK. The intra-renal distribution of ANK was determined by immunohistochemistry and the subcellular distribution in mIMCD3 cells by transfection of an ANK-NT-GFP fusion protein. Furthermore, an inactivating mutation of murine ank, Glu440X, and a gain of function mutation, Met48Thr, were tested to determine whether membrane traffic contributed to a transport defect. RESULTS ANK is expressed in cells of the cortical collecting duct, as assessed by colocalisation with aquaporin 2 and at the lateral and apical plasma membranes of mIMCD-3 epithelial cells, as assessed by colocalisation with wheat germ agglutinin lectin (WGA). ANK-NT-GFP was also present in endoplasmic reticulum, Golgi, acidic endosomes and mitochondria. mIMCD3 expression of Glu440X ANK-NT-GFP shows evidence of Golgi retention whereas Met48Thr ANK-NT-GFP is unaltered at the plasma membrane compared to wild type. CONCLUSION The intra-renal and subcellular localisation of ANK is consistent with pyrophosphate export from collecting duct cells and supports a role for ANK in limiting intra-renal calcium-crystal formation.
Collapse
Affiliation(s)
- Georgina Carr
- Epithelial Transport Research Group, Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, UK
| | | | | |
Collapse
|
7
|
Ludwig M, Utsch B, Monnens LAH. Recent advances in understanding the clinical and genetic heterogeneity of Dent's disease. Nephrol Dial Transplant 2006; 21:2708-17. [PMID: 16861240 DOI: 10.1093/ndt/gfl346] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Michael Ludwig
- Department of Clinical Biochemistry, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn, Germany.
| | | | | |
Collapse
|
8
|
Reyes JP, Hernandez-Carballo CY, Pérez-Cornejo P, Meza U, Espinosa-Tanguma R, Arreola J. Novel outwardly rectifying anion conductance in Xenopus oocytes. Pflugers Arch 2005; 449:271-7. [PMID: 15452709 DOI: 10.1007/s00424-004-1324-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We describe a novel, strongly outwardly rectifying anion current in Xenopus laevis oocytes, that we have named I(Cl,Or)- The properties of I(Cl,Or) are different from those of any other anion conductance previously described in these cells. Typically, I(Cl,Or) amplitude was small when extracellular Cl- (Cle) was the permeant anion. However, when Cle was replaced by lyotropic anions I(Cl,Or) became evident as a time-independent current. (ICl,Or) was voltage dependent and showed a remarkable outwards rectification with little or no inwards tail current. The relative selectivity sequence determined from current amplitudes was: SCN- > or = ClO4- > I- > Br- > or = NO3- > Cl- x I(Cl,Or) was insensitive to Gd3+ but was blocked by micromolar concentrations of niflumic acid, DIDS or Zn2+. Furthermore, I(Cl,Or) was not affected by buffering intracellular Ca2+ with BAPTA. Low extracellular pH inhibited I(Cl,Or) with a pK of 5.8. We propose that I(Cl,Or) might result from activation of endogenous ClC-5-like Cl- channels present in Xenopus oocytes.
Collapse
Affiliation(s)
- Juan P Reyes
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava 6, Zona Universitaria, SLP 78290 San Luis Potosí, México
| | | | | | | | | | | |
Collapse
|
9
|
Sayer JA, Carr G, Simmons NL. Calcium phosphate and calcium oxalate crystal handling is dependent upon CLC-5 expression in mouse collecting duct cells. Biochim Biophys Acta Mol Basis Dis 2004; 1689:83-90. [PMID: 15158917 DOI: 10.1016/j.bbadis.2004.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Revised: 02/03/2004] [Accepted: 02/27/2004] [Indexed: 10/26/2022]
Abstract
Defects in an intracellular chloride channel CLC-5 cause Dent's disease, an inherited kidney stone disorder. Using a collecting duct model, mIMCD-3 cells, we show expression of dimeric mCLC-5. Transient transfection of antisense CLC-5 reduces CLC-5 protein expression. Binding of both calcium phosphate (hydroxyapatite) and calcium oxalate monohydrate (COM) crystals overlaid onto mIMCD-3 cultures was affected by altered CLC-5 expression. Calcium phosphate crystal agglomerations (>10 microm) were minimal in control (9%) and sense (13%) CLC-5-transfected cells, compared to 66% of antisense CLC-5-transfected cells (P<0.001). Small calcium phosphate crystals (<10 microm) were found associated with 45% of sense CLC-5-treated cells, of which the majority (11/14 cells) appeared to be internalised within the cell. Calcium oxalate agglomerations (>10 microm) were also largely absent for controls or sense mCLC-5 transfectants (11% and 9% of cells, respectively) with COM crystal agglomerates predominating in antisense CLC-5 transfectants (66%, P<0.0001). We conclude that collecting duct cells with reduced CLC-5 expression lead to a tendency to form calcium crystal agglomeration, which may help explain the nephrocalcinosis and nephrolithiasis seen in Dent's disease.
Collapse
Affiliation(s)
- J A Sayer
- School of Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, NE2 4HH, UK.
| | | | | |
Collapse
|
10
|
Pham PC, Devuyst O, Pham PT, Matsumoto N, Shih RNG, Jo OD, Yanagawa N, Sun AM. Hypertonicity increases CLC-5 expression in mouse medullary thick ascending limb cells. Am J Physiol Renal Physiol 2004; 287:F747-52. [PMID: 15161605 DOI: 10.1152/ajprenal.00229.2003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Genetic studies indicated that mutations of the chloride channel CLC-5 in the kidney are responsible for a group of clinical disorders, collectively called Dent's disease. In the kidney, CLC-5 was found to be expressed in the proximal tubule, medullary thick ascending limb (mTAL) of loop of Henle, and intercalated cells of the collecting tubule. In proximal tubular cells, CLC-5 was found to play an important role in receptor-mediated endocytosis. However, the functional roles of CLC-5 in mTAL and collecting tubules remain unclear. Because mTAL is normally exposed to a hypertonic environment, we aimed to examine the effect of hypertonicity on CLC-5 expression in this nephron segment. Our studies revealed that exposure to hypertonicity (up to 550 mosM) increased CLC-5 mRNA and protein levels in a murine mTAL cell line (MTAL) but not in an opossum kidney (OK) proximal tubular cell line. A similar effect was also found in mouse kidneys, where CLC-5 expression was enhanced in renal medulla, but not cortex, after 48 h of water deprivation. We also tested the effect of hypertonicity on endocytotic activity and found that exposure to hypertonicity caused a significant decrease in cellular uptake of FITC-labeled albumin in OK but not in MTAL cells. Our results suggest that CLC-5 expression is upregulated by hypertonicity in mTAL cells but not in proximal tubular cells. We speculate that the increased CLC-5 levels in mTAL may serve to maintain the endocytotic activity in a hypertonic environment.
Collapse
Affiliation(s)
- Phuong-Chi Pham
- Renal Division, Department of Medicine, Olive View-UCLA Medical Center, Sylmar, CA 91342, USA.
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Carr G, Simmons N, Sayer J. A role for CBS domain 2 in trafficking of chloride channel CLC-5. Biochem Biophys Res Commun 2003; 310:600-5. [PMID: 14521953 DOI: 10.1016/j.bbrc.2003.09.057] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
CLC-5 is a member of the CLC family of voltage-gated chloride channels. Mutations disrupting CLC-5 lead to Dent's disease, an X-linked renal tubular disorder, characterised by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, and renal stones. Sequence analysis of CLC-5 reveals a 746 amino acid protein with an intracellular amino-terminus, transmembrane spanning domains, and two CBS domains within its intracellular carboxy-terminus. CBS domains have been implicated in intracellular targetting and trafficking as well as protein-protein interactions. We investigate subcellular localisation of three naturally occurring CLC-5 mutants which all lead to a truncated protein, disrupting the second CBS domain. These mutants are unable to traffic normally to acidic endosomes but are retained in perinuclear compartments, colocalising with the Golgi complex. This is the first identification of the cellular pathogenesis of CBS domain mutations of CLC-5.
Collapse
Affiliation(s)
- Georgina Carr
- School of Cell and Molecular Biosciences, University of Newcastle, Framlington Place, Newcastle Upon Tyne NE2 4HH, UK
| | | | | |
Collapse
|
12
|
Sayer JA, Carr G, Pearce SHS, Goodship THJ, Simmons NL. Disordered calcium crystal handling in antisense CLC-5-treated collecting duct cells. Biochem Biophys Res Commun 2003; 300:305-10. [PMID: 12504084 DOI: 10.1016/s0006-291x(02)02837-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Dent's disease, an X-linked tubulopathy secondary to defects in chloride channel CLC-5, is characterised by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, and renal stones. Mechanisms leading to nephrocalcinosis are unknown. Using a murine collecting duct cell line (mIMCD-3), we confirm endogenous expression of mCLC-5. During transfection of antisense CLC-5, we observe a reduction in CLC-5 protein expression that correlates with a reduction in the number of acidic endosomal compartments, as determined by quantitative analysis of confocal microscope images using LysoTracker Red. Using wheat germ agglutinin-lectin as an endocytic marker, an arrest of endocytosis is observed in antisense CLC-5 treated cells. Exposure of the cell surface to calcium oxalate crystals results in crystal agglomeration in a minority of sense CLC-5 transfectants (45%) and all antisense CLC-5 transfectants. We conclude that expression of CLC-5 in mIMCD-3 cells allows acidification of endosomes and endocytosis, and that disruption of CLC-5 expression causes abnormal crystal agglomeration.
Collapse
Affiliation(s)
- John A Sayer
- Department of Medicine, University of Newcastle Upon Tyne, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
| | | | | | | | | |
Collapse
|
13
|
Isnard-Bagnis C, Da Silva N, Beaulieu V, Yu ASL, Brown D, Breton S. Detection of ClC-3 and ClC-5 in epididymal epithelium: immunofluorescence and RT-PCR after LCM. Am J Physiol Cell Physiol 2003; 284:C220-32. [PMID: 12475763 DOI: 10.1152/ajpcell.00374.2001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epithelial cells of the epididymis and vas deferens establish an optimum luminal environment in which spermatozoa mature and are stored. This is achieved by active transepithelial transport of various ions including Cl(-) and H(+). We investigated the localization of three closely related members of the ClC family, ClC-3, ClC-4, and ClC-5, in the epididymis and vas deferens. RT-PCR using mRNA isolated by laser capture microdissection (LCM)-detected ClC-3 and ClC-5 transcripts but did not detect any ClC-4-specific transcript. Western blot and immunofluorescence analysis demonstrated that ClC-3 and ClC-5 proteins are present in all regions of the epididymis and in the vas deferens. ClC-5 is expressed exclusively in H(+)-ATPase-rich cells (narrow and clear cells). Confocal microscopy showed that ClC-5 partially colocalizes with the H(+)-ATPase in the subapical pole of clear cells. ClC-3 is strongly expressed in the apical membrane of principal cells of the caput epididymidis and the vas deferens and is less abundant in principal cells of the body and cauda epididymidis. These findings are consistent with a potential role for ClC-3 in transepithelial chloride transport by principal cells and for ClC-5 in the acidification of H(+)-ATPase-containing vesicles in narrow and clear cells. ClC-5 might facilitate endosome trafficking in the epididymis, as has been proposed in the kidney.
Collapse
Affiliation(s)
- Corinne Isnard-Bagnis
- Renal Unit and Program in Membrane Biology, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129, USA
| | | | | | | | | | | |
Collapse
|
14
|
Schmieder S, Lindenthal S, Ehrenfeld J. Cloning and characterisation of amphibian ClC-3 and ClC-5 chloride channels. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1566:55-66. [PMID: 12421537 DOI: 10.1016/s0005-2736(02)00594-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Amphibians have provided important model systems to study transepithelial transport, acid-base balance and cell volume regulation. Several families of chloride channels and transporters are involved in these functions. The purpose of this review is to report briefly on some of the characteristics of the chloride channels so far reported in amphibian epithelia, and to focus on recently cloned members of the ClC family and their possible physiological roles. The electrophysiological characterisation, distribution, localisation and possible functions are reviewed and compared to their mammalian orthologs.
Collapse
Affiliation(s)
- S Schmieder
- Laboratoire de Physiologie des Membranes Cellulaires, Université de Nice-Sophia Antipolis, UMR 6078/CNRS, 284 Chemin du Lazaret, BP 68, Villefranche sur Mer, France
| | | | | |
Collapse
|
15
|
Renal expression of Ca2+-activated Cl− channels. CURRENT TOPICS IN MEMBRANES 2002. [DOI: 10.1016/s1063-5823(02)53038-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|