| Type: | Family | Name: | Voltage gated sodium channel, alpha-4 subunit |
| Description: | Voltage-dependent sodium channels are transmembrane (TM) proteins responsible for the depolarising phase of the action potential in mostelectrically excitable cells []. They may exist in 3 states []: theresting state, where the channel is closed; the activated state, where the channel is open; and the inactivated state, where the channel is closedand 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 currentsfound in excitable tissues. The structure of sodium channels is based on 4 internal repeats of a 6-helix bundle [] (in which 5 of the membrane-spanning segments are hydrophobic andthe other is positively charged), forming a 24-helical bundle. The charged segments are believed to be localised within clusters formed by their 5 hydrophobic neighbours: it is postulated that the charged domain may be the voltage sensor region, possibly moving outward on depolarisation, causing aconformational change. This model [] contrastswith another [], in which the TM segments are juxtaposedoctagonally. The basic structural motif (the 6-helix bundle) is also found in potassium and calcium channel alpha subunits.This entry represents the voltage-gated sodium channel alpha-4 subunit (Nav1.4, also known as SCN4A). Nav1.4 is expressed in skeletal muscle []. Mutations in Nav1.4 gene cause several diseases in humans, such as Paramyotonia congenita of von Eulenburg (PMC), Myotonia SCN4A-related (MYOSCN4A) and Periodic paralysis hyperkalemic (HYPP) [, , , , , ]. | Short Name: | Na_channel_a4su |
| DB identifier | Type | Name |
|---|---|---|
| IPR008052 | Family | Voltage gated sodium channel, alpha-4 subunit, mammalian |
| GO Term | Gene Name |
|---|---|
| GO:0005248 | IPR028826 |
| GO:0006814 | IPR028826 |
| GO:0001518 | IPR028826 |
| DB identifier | Type | Name |
|---|---|---|
| IPR001696 | Family | Voltage gated sodium channel, alpha subunit |
