| Type: | Family | Name: | Chloride channel, voltage-gated, ClcB |
| Description: | Chloride channels (CLCs) constitute an evolutionarily well-conserved family of voltage-gated channels that are structurally unrelated to the other known voltage-gated channels. They are found in organisms ranging from bacteria to yeasts and plants, and also to animals. Their functions in higher animals likely include the regulation of cell volume, control of electrical excitability and trans-epithelial transport [].The first member of the family (CLC-0) was expression-cloned from the electric organ of Torpedo marmorata [], and subsequently nine CLC-like proteins have been cloned from mammals. They are thought to function as multimers of two or more identical or homologous subunits, and they have varying tissue distributions and functional properties. To date, CLC-0, CLC-1, CLC-2, CLC-4 and CLC-5 have been demonstrated to form functional Cl- channels; whether the remaining isoforms do so is either contested or unproven. One possible explanation for the difficulty in expressing activatable Cl- channels is that some of the isoforms may function as Cl- channels of intracellular compartments, rather than of the plasma membrane. However, they are all thought to have a similar transmembrane (TM) topology, initial hydropathy analysis suggesting 13 hydrophobic stretches long enough to form putative TM domains []. Recently, the postulated TM topology has been revised, and it now seems likely that the CLCs have 10 (or possibly 12) TM domains, with both N- and C-termini residing in the cytoplasm [].This entry represents bacterial voltage-gated chloride channel of the ClcB type. ClcB probably acts as an electrical shunt for an outwardly-directed proton pump that is linked to amino acid decarboxylation, as part of the extreme acid resistance (XAR) response []. | Short Name: | Cl-channel_volt-gated_ClcB |
