Voltage-Gated Sodium Channel Protein Alpha Subunit (VGSC alpha subunit)

The voltage-gated sodium channel protein alpha subunit is the principal pore-forming component of voltage-gated sodium channels (VGSCs), which are essential for the initiation and propagation of action potentials in excitable cells. The alpha subunit alone is sufficient to form a functional sodium channel, but its properties can be modulated by auxiliary beta subunits. It consists of four homologous domains (I–IV), each containing six transmembrane segments (S1–S6). The S4 segment in each domain acts as the voltage sensor. Segments S5 and S6, along with the intervening pore loop, form the ion-conducting pore and activation gate. A critical intracellular loop between domains III and IV forms the fast inactivation gate. Different isoforms exist with tissue-specific expression. Mutations or dysregulation can cause "sodium channelopathies."

Other names

Sodium channel alpha subunitNav alpha subunit

Blocks sodium channel, preventing sodium influx and inhibiting action potential firing