Scn9a in combination with a regulatory beta subunit responds to depolarization by opening and passively transporting sodium ions according to the concentration gradient from the extracellular region to the cytosol (Gao et al. 2009). In mouse type II taste cells, initial depolarization at the apex of the cell is believed to cause an activation potential via Scn2a, Scn3a, and Scn9a located at the basolateral membrane (Gao et al. 2009). Beta units Scn1b, Scn2b, and Scn4b are expressed in taste cells (Shandilya et al. 2016).
sodium channel activity of Scn9a:Scn1b,2b,4b [plasma membrane]