Expression and regulation of ClC-5 chloride channels: effects of antisense and oxidants

T. X. Weng, L. Mo, H. L. Hellmich, A. S. L. Yu, T. Wood, N. K. Wills
2001 American Journal of Physiology - Cell Physiology  
Expression and regulation of ClC-5 chloride channels: effects of antisense and oxidants. Am J Physiol Cell Physiol 280: C1511-C1520, 2001.-Genetic mutations of the Cl Ϫ channel ClC-5 cause Dent's disease in humans. We recently cloned an amphibian ortholog of Xenopus ClC-5 (xClC-5) from the A6 cell line. We now compare the properties and regulation of ClC-5 currents expressed in mammalian (COS-7) cells and Xenopus oocytes. Whole cell currents in COS-7 cells transfected with xClC-5 cDNA had
more » ... lC-5 cDNA had strong outward rectification, Cl Ϫ Ͼ I Ϫ anion sensitivity, and were inhibited at low pH, similar to previous results in oocytes. In oocytes, antisense xClC-5 cRNA injection had no effect on endogenous membrane currents or the heterologous expression of human ClC-5. Activators of cAMP and protein kinase C inhibitors had no significant effects on ClC-5 currents expressed in either COS-7 cells or oocytes, whereas H-89, a cAMP-dependent protein kinase (PKA) inhibitor, and hydrogen peroxide decreased the currents. We conclude that the basic properties of ClC-5 currents were independent of the host cell type used for expression. In addition, ClC-5 channels may be modulated by PKA and reactive oxygen species. Dent's disease; Xenopus oocytes; mammalian COS-7 cells; patch clamp; hydrogen peroxide CLC CHANNELS are a rapidly growing and large family of voltage-gated Cl Ϫ channels that are found in a wide variety of organisms including bacteria, yeast, plants, fish, amphibians, and mammals (11, 21, 23). To date, at least nine different human ClC genes have been isolated. Loss of function mutations of one member of this family, ClC-5, have been linked to the human hereditary renal disorder, Dent's disease (18). Recently, we isolated a homologue of the Xenopus ClC-5 channel (xClC-5) from the amphibian cultured renal cell line A6 (16, 22). When expressed in Xenopus oocytes (22, 26), xClC-5 currents showed strong outward rectification and were inhibited by acidic extracellular pH. These conductance properties were essentially identical to those of human ClC-5 (hClC-5) or rat ClC-5 (rClC-5) expressed in Xenopus oocytes (18, 27) .
doi:10.1152/ajpcell.2001.280.6.c1511 pmid:11350746 fatcat:y6jumoxkmbbtlkuz7a6s26kdv4