Voltage gated sodium channel, alpha subunit
IPR001696
Definition
Voltage-dependent sodium channels are transmembrane (TM) proteins responsible for the depolarising phase of the action potential in most electrically excitable cells PMID:1317577. They may exist in 3 states PMID:1323284: the resting state, where the channel is closed; the activated state, where the channel is open; and the inactivated state, where the channel is closed and refractory to opening. Several different structurally and functionally distinct isoforms are found in mammals, coded for by a multigene family, these being responsible for the different types of sodium ion currents found in excitable tissues. There are nine pore-forming alpha subunit of voltage-gated sodium channels consisting of four membrane-embedded homologous domains (I-IV), each consisting of six α-helical segments (S1-S6), three cytoplasmic loops connecting the domains, and a cytoplasmic C-terminal tail. The S6 segments of the four domains form the inner surface of the pore, while the S4 segments bear clusters of basic residues that constitute the channel's voltage sensors [[cite:PMID:6209577], [cite:PMID:21947499], [cite:PMID:27143702]]. Cation channels are transport proteins responsible for the movement of cations through the membrane. These proteins contain 6 transmembrane helices in which the last two helices flank a loop which determines ion selectivity. In some sub-families (e.g. Na channels) the domain is repeated four times, whereas in others (e.g. K channels) the protein forms as a tetramer in the membrane.
10 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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