SCN5A Variants: Association With Cardiac Disorders

Figures

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  Figure 1. Nav1.5 protein structure and some typical variants associated with gain- or loss- of the sodium channel function. Nav1.5 is a large transmembrane protein with four internally homologous domains (DI-DIV), each containing six spanning segments (S1–S6) which are indicated by numbered cylinders. The four domains are interconnected by intracellular peptide chains, with N-terminal and C-end both located in the intracellular side. S4 segment works as a critical voltage-sensor because of its ample positive charge residues; S5 and S6 segments are lined by extracellular loops (P-loops) which are considered to determine the ion selectivity of the channel (S4 segments are depicted in yellow while the rest segments being blue). The transmembrane segment resembles one of the beta-subunits, which is depicted in purple. The location of the gain-of-function SCN5A variants are shown in blue circle while location of the loss-of-function SCN5A variants are shown in red rhombus.