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ClC-3-like chloride channel proteins. This CD includes ClC-3, ClC-4, ClC-5 and ClC-Y1. ClC-3 was initially cloned from rat kidney. Expression of ClC-3 produces outwardly-rectifying Cl currents that are inhibited by protein kinase C activation. It has been suggested that ClC-3 may be a ubiquitous swelling-activated Cl channel that has very similar characteristics to those of native volume-regulated Cl currents. The function of ClC-4 is unclear. Studies of human ClC-4 have revealed that it gives rise to Cl currents that rapidly activate at positive voltages, and are sensitive to extracellular pH, with currents decreasing when pH falls below 6.5. ClC-4 is broadly distributed, especially in brain and heart. ClC-5 is predominantly expressed in the kidney, but can be found in the brain and liver. Mutations in the ClC-5 gene cause certain hereditary diseases, including Dent's disease, an X-chromosome linked syndrome characterised by proteinuria, hypercalciuria, and kidney stones (nephrolithiasis), leading to progressive renal failure. 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. This domain is found in the eukaryotic halogen ion (Cl- and I-) channel proteins, that perform a variety of functions including cell volume regulation, the membrane potential stabilization, transepithelial chloride transport and charge compensation necessary for the acidification of intracellular organelles.
Jiyao W et al.(2023). "The conserved domain database in 2023.",