Voltage-gated chloride channel. Chloride channels have several functions including the regulation of cell volume; membrane potential stabilization, signal transduction and transepithelial transport. May be important in urinary concentrating mechanisms. Activated by extracellular calcium and inhibited by extracellular protons. Homodimer (PubMed:17562318). Interacts with BSND. Forms heteromers with BSND in the thin ascending limb of Henle (By similarity). Expressed predominantly in the kidney. All nephron segments expressing BSND also express CLCNK proteins. The disease is caused by variants affecting distinct genetic loci, including the gene represented in this entry. Loss-of-function of both CLCNKA and CLCNKB results in the disease phenotype (PubMed:18310267). Belongs to the chloride channel (TC 2.A.49) family. CLCNKA subfamily.