Swelling-activated Chloride and Potassium Conductance in Primary Cultures of Mouse Proximal Tubules. Implication of KCNE1 Protein |
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Authors: | H?Barrière I?Rubera R?Belfodil M?Tauc N?Tonnerieux Email author" target="_blank">C?PoujeolEmail author J?Barhanin P?Poujeol |
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Institution: | (1) UMR CNRS 6548, Université de Nice-Sophia Antipolis, 06108 Nice Cedex 2, France;(2) UMR CNRS 6097, IPMC, Sophia Antipolis, 06560 Valbonne, France |
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Abstract: | Volume-sensitive chloride and potassium currents were studied, using the whole-cell clamp technique, in cultured wild-type mouse proximal convoluted tubule (PCT) epithelial cells and compared with those measured in PCT cells from null mutant kcne1 –/– mice. In wild-type PCT cells in primary culture, a Cl– conductance activated by cell swelling was identified. The initial current exhibited an outwardly rectifying current-voltage (I-V) relationship, whereas steady-state current showed decay at depolarized membrane potentials. The ion selectivity was I– > Br– > Cl– >> gluconate. This conductance was sensitive to 1 mM 4,4 -Diisothiocyanostilbene-2,2 -disulfonic acid (DIDS), 0.1 mM 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and 1 mM diphenylamine-2-carboxylate (DPC). Osmotic stress also activated K+ currents. These currents are time-independent, activated at depolarized potentials, and inhibited by 0.5 mM quinidine, 5 mM barium, and 10 µM clofilium but are insensitive to 1 mM tetraethylammonium (TEA), 10 nM charybdotoxin (CTX), and 10 µM 293B. In contrast, the null mutation of kcne1 completely impaired volume-sensitive chloride and potassium currents in PCT. The transitory transfection of kcne1 restores both Cl– and K+ swelling-activated currents, confirming the implication of KCNE1 protein in the cell-volume regulation in PCT cells in primary cultures. |
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Keywords: | Cell volume kcne1 Kidney Chloride conductance Potassium conductance |
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