Chloride channel, ClC. These domains are found in the eukaryotic halogen ion (Cl-, Br- and I-) channel proteins that perform a variety of functions including cell volume regulation, membrane potential stabilization, charge compensation necessary for the acidification of intracellular organelles, signal transduction and transepithelial transport. They are also involved in many pathophysiological processes and are responsible for a number of human diseases. These proteins belong to the ClC superfamily of chloride ion channels, which share the unique double-barreled architecture and voltage-dependent gating mechanism. The gating is conferred by the permeating anion itself, acting as the gating charge. Some proteins possess long C-terminal cytoplasmic regions containing two CBS (cystathionine beta synthase) domains of putative regulatory function.