Open AccessVoltage-gated sodium channels (Na<sub>V</sub>) in GtoPdb v.2021.3
Author(s) -
William A. Catterall,
Alan L. Goldin,
Stephen G. Waxman
Publication year - 2021
Publication title -
iuphar/bps guide to pharmacology cite
Language(s) - English
Resource type - Journals
ISSN - 2633-1020
DOI - 10.2218/gtopdb/f82/2021.3
Subject(s) - sodium channel , chemistry , transmembrane protein , transmembrane domain , sodium , biophysics , ion channel , gating , kcsa potassium channel , potassium channel , protein subunit , voltage gated ion channel , transmembrane channels , membrane potential , selectivity , extracellular , membrane , biochemistry , receptor , biology , gene , organic chemistry , catalysis
Sodium channels are voltage-gated sodium-selective ion channels present in the membrane of most excitable cells. Sodium channels comprise of one pore-forming α subunit, which may be associated with either one or two β subunits [177]. α-Subunits consist of four homologous domains (I-IV), each containing six transmembrane segments (S1-S6) and a pore-forming loop. The positively charged fourth transmembrane segment (S4) acts as a voltage sensor and is involved in channel gating. The crystal structure of the bacterial NavAb channel has revealed a number of novel structural features compared to earlier potassium channel structures including a short selectivity filter with ion selectivity determined by interactions with glutamate side chains [274]. Interestingly, the pore region is penetrated by fatty acyl chains that extend into the central cavity which may allow the entry of small, hydrophobic pore-blocking drugs [274]. Auxiliary β1, β2, β3 and β4 subunits consist of a large extracellular N-terminal domain, a single transmembrane segment and a shorter cytoplasmic domain.The nomenclature for sodium channels was proposed by Goldin et al., (2000) [144] and approved by the NC-IUPHAR Subcommittee on sodium channels (Catterall et al., 2005, [52]).