Voltage-gated sodium channels are transmembrane glycoprotein complexes composed of a large alpha subunit and one or more regulatory beta subunits. They are responsible for the generation and propagation of action potentials in neurons and muscle. This gene encodes one member of the sodium channel beta subunit gene family, and influences the inactivation kinetics of the sodium channel. Two alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Jul 2008].