<Tr> <Th> TCDB </Th> <Td> 1. A. 1 </Td> </Tr> <Tr> <Th> OPM superfamily </Th> <Td> 8 </Td> </Tr> <Tr> <Th> OPM protein </Th> <Td> 2a79 </Td> </Tr> <P> Voltage - gated ion channels are a class of transmembrane proteins that form ion channels that are activated by changes in the electrical membrane potential near the channel . The membrane potential alters the conformation of the channel proteins, regulating their opening and closing . Cell membranes are generally impermeable to ions, thus they must diffuse through the membrane through transmembrane protein channels . They have a crucial role in excitable cells such as neuronal and muscle tissues, allowing a rapid and co-ordinated depolarization in response to triggering voltage change . Found along the axon and at the synapse, voltage - gated ion channels directionally propagate electrical signals . Voltage - gated ion - channels are usually ion - specific, and channels specific to sodium (Na), potassium (K), calcium (Ca), and chloride (Cl) ions have been identified . The opening and closing of the channels are triggered by changing ion concentration, and hence charge gradient, between the sides of the cell membrane . </P>

How is a leak channel different from a chemically gated channel and voltage-gated channel