Voltage-gated sodium channels play an important role in the generation and propagation of action potentials in excitable cells. They are composed of a pore-forming α subunit and auxiliary β subunits. To date, nine subtypes of the α subunit, designated Nav1.1 to Nav1.9, have been shown to form functional sodium channels. In addition, four different mammalian subunits （β1-β4） isoforms have been cloned from the nervous system. The β subunits are structurally homologous and form single transmembrane glycoproteins with short intracellular loops and immunoglobulin-like extracellular segments. The association of the various α subtypes with different combinations of auxiliary β subunits creates the possibility of additional molecular and functional complexity for neuronal sodium channels.
WANG Ying-weiCHENG Zhi-junTAN HongXIA Yi-mengREN Rong-rongDING Yu-qiang
