Protein Domain : Voltage gated sodium channel, alpha-5 subunit IPR008053

Type	Family
Description	Voltage-dependent sodium channels are transmembrane (TM) proteins responsible for the depolarising phase of the action potential in most electrically excitable cells []. They may exist in 3 states []: 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 [ , , ].The SCN5A gene encodes the NaH1 channel and is expressed in cardiac muscle, foetal skeletal muscle and denervated adult skeletal muscle. Mutationsin the SCN5A gene affect the function of NaH1 channels in the heart and areone of the three causes of Long QT syndrome, an inherited cardiac arrhythmia that can cause abrupt loss of consciousness, seizures and sudden death []; it is also associated with Brugada syndrome [ ] and conduction systemdisease [ ].
Short Name	Na_channel_a5su