Cloning and expression of a PKC-regulated chloride channel.

The cDNA of a protein kinase C-regulated chloride channel (CIC-3) was cloned. CIC-3 encodes 760 amino acids, which has significant amino acid identity with the previously cloned CIC chloride channels. CIC-3 cRNA elicited the chloride currents in Xenopus oocytes, which was completely blocked by activation of protein kinase C by 12-O-tetradecanoylphorbol 13-acetate (TPA). The most abundant expression of CIC-3 mRNA was observed in rat brain, and the moderate level of CIC-3 expression was also observed in various rat tissues including adrenal gland, kidney, and lung. These findings suggest that CIC-3 may have important roles in various types of cells with regulation by protein kinase C.