Cl- interference with the epithelial Na+ channel ENaC

被引:43
作者
Bachhuber, T [1 ]
König, J [1 ]
Voelcker, T [1 ]
Mürle, B [1 ]
Schreiber, R [1 ]
Kunzelmann, K [1 ]
机构
[1] Univ Regensburg, Inst Physiol, Univ Str 31, D-93053 Regensburg, Germany
关键词
D O I
10.1074/jbc.M504347200
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The cystic fibrosis transmembrane conductance regulator (CFTR) is a protein kinase A and ATP-regulated Cl- channel that also controls the activity of other membrane transport proteins, such as the epithelial Na+ channel ENaC. Previous studies demonstrated that cytosolic domains of ENaC are critical for down-regulation of ENaC by CFTR, whereas others suggested a role of cytosolic Cl- ions. We therefore examined in detail the anion dependence of ENaC and the role of its cytosolic domains for the inhibition by CFTR and the Cl- channel CLC-0. Coexpression of rat ENaC with human CFTR or the human Cl- channel CLC-0 caused inhibition of amiloride-sensitive Na+ currents after cAMP-dependent stimulation and in the presence of a 100 mM bath Cl- concentration. After activation of CFTR by 3-isobutyl-1-methylxanthine and forskolin or expression of CLC-0, the intracellular Cl- concentration was increased in Xenopus oocytes in the presence of a high bath Cl- concentration, which inhibited ENaC without changing surface expression of alpha beta gamma ENaC. In contrast, a 5 mM bath Cl- concentration reduced the cytosolic Cl- concentration and enhanced ENaC activity. ENaC was also inhibited by injection of Cl- into oocytes and in inside/out macropatches by exposure to high cytosolic Cl- concentrations. The effect of Cl- was mimicked by Br-, NO3-, and I-. Inhibition by Cl- was reduced in trimeric channels with a truncated COOH terminus of beta ENaC and gamma ENaC, and it was no longer detected in dimeric alpha beta gamma ENaC channels. Deletion of the NH2 terminus of alpha-, beta-, or gamma ENaC, mutations in the NH2-terminal phosphatidylinositol bisphosphate-binding domain of beta ENaC and gamma EnaC, and activation of phospholipase C, all reduced ENaC activity but allowed for Cl--dependent inhibition of the remaining ENaC current. The results confirm a role of the carboxyl terminus of beta ENaC for Cl-- dependent inhibition of the Na+ channel, which, however, may only be part of a complex regulation of ENaC by CFTR.
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页码:31587 / 31594
页数:8
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共 64 条
[1]   Increase in intracellular Cl- concentration by cAMP- and Ca2+-dependent stimulation of M1 collecting duct cells [J].
Adam, G ;
Ousingsawat, J ;
Schreiber, R ;
Kunzelmann, K .
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, 2005, 449 (05) :470-478
[2]   Gating of amiloride-sensitive Na+ channels:: Subunit-subunit interactions and inhibition by the cystic fibrosis transmembrane conductance regulator [J].
Berdiev, BK ;
Shlyonsky, VG ;
Karlson, KH ;
Stanton, BA ;
Ismailov, II .
BIOPHYSICAL JOURNAL, 2000, 78 (04) :1881-1894
[3]   NA+ TRANSPORT IN CYSTIC-FIBROSIS RESPIRATORY EPITHELIA - ABNORMAL BASAL RATE AND RESPONSE TO ADENYLATE-CYCLASE ACTIVATION [J].
BOUCHER, RC ;
STUTTS, MJ ;
KNOWLES, MR ;
CANTLEY, L ;
GATZY, JT .
JOURNAL OF CLINICAL INVESTIGATION, 1986, 78 (05) :1245-1252
[4]   Molecular insights into the physiology of the 'thin film' of airway surface liquid [J].
Boucher, RC .
JOURNAL OF PHYSIOLOGY-LONDON, 1999, 516 (03) :631-638
[5]   EVIDENCE FOR REDUCED CL- AND INCREASED NA+ PERMEABILITY IN CYSTIC-FIBROSIS HUMAN PRIMARY-CELL CULTURES [J].
BOUCHER, RC ;
COTTON, CU ;
GATZY, JT ;
KNOWLES, MR ;
YANKASKAS, JR .
JOURNAL OF PHYSIOLOGY-LONDON, 1988, 405 :77-103
[6]   Role of CFTR's PDZ1-binding domain, NBF1 and Cl- conductance in inhibition of epithelial Na+ channels in Xenopus oocytes [J].
Boucherot, A ;
Schreiber, R ;
Kunzelmann, K .
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES, 2001, 1515 (01) :64-71
[7]   Cl- transport by cystic fibrosis transmembrane conductance regulator (CFTR) contributes to the inhibition of epithelial Na+ channels (ENaCs) in Xenopus oocytes co-expressing CFTR and ENaC [J].
Briel, M ;
Greger, R ;
Kunzelmann, K .
JOURNAL OF PHYSIOLOGY-LONDON, 1998, 508 (03) :825-836
[8]   Epithelial sodium channel inhibition by AMP-activated protein kinase in oocytes and polarized renal epithelial cells [J].
Carattino, MD ;
Edinger, RS ;
Grieser, HJ ;
Wise, R ;
Neumann, D ;
Schlattner, U ;
Johnson, JP ;
Kleyman, TR ;
Hallows, KR .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2005, 280 (18) :17608-17616
[9]   Downregulation of epithelial sodium channel (ENaC) by CFTR co-expressed in Xenopus oocytes is independent of Cl- conductance [J].
Chabot, H ;
Vives, MF ;
Dagenais, A ;
Grygorczyk, C ;
Berthiaume, Y ;
Grygorczyk, R .
JOURNAL OF MEMBRANE BIOLOGY, 1999, 169 (03) :175-188
[10]   The NH2 terminus of the epithelial sodium channel contains an endocytic motif [J].
Chalfant, ML ;
Denton, JS ;
Langloh, AL ;
Karlson, KH ;
Loffing, J ;
Benos, DJ ;
Stanton, BA .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1999, 274 (46) :32889-32896