Nine voltage-gated sodium channels (Navs) are expressed in complex patterns in mammalian nerve and muscle. These channels mediate the influx of Na+ ions in response to local depolarising stimuli. Nav channels are composed of a pore-forming alpha-subunit associated with one or more auxiliary beta-subunits. The pore-forming alpha subunit is sufficient for functional expression, but the localisation, kinetics and voltage dependence of channel gating are modified by the beta subunits [, ].Sodium channel protein type 9 subunit alpha (also known as Nav1.7 or SCN9A) is strongly expressed in nociceptive neurons and plays a role in pain mechanisms, especially in the development of inflammatory pain [, , ]. It interacts with the ubiquitin-protein ligases Nedd4 and Nedd4-2, known to regulate receptors and ion transporters [].
