Fig. 3.

Voltage-gated Na⁺ channel auxiliary subunits. Voltage-gated Na⁺ channels (VGSCs) contain a conducting Na_vα subunit and auxiliary Na_vβ subunits. Na_vα consists of four domains (domains I-IV), each containing six segments (S1-S6). The voltage-sensing domain is found within S4 of each domain and the pore consists of the P-loop found between S5-6 of each domain. Na_vβs function as cell adhesion molecules via an extracellular immunoglobulin domain [238,239,332]. Na_vβs also induce neurite outgrowth and migration [245] and the intracellular domain of Na_vβ₂ has putative transcription regulation function [248].