8.A.17.1.4
Na⁺ channel SCN5A (see 1.A.1.10.3) regulatory subunit of 218 aas and 2 TMSs, N- and C-terminal.  It is a regulatory subunit of multiple voltage-gated sodium channel complexes that play important roles in excitable membranes in brain, heart and skeletal muscle. It enhances the presence of the pore-forming alpha subunit at the cell surface and modulates channel gating characteristics and the rate of channel inactivation. It modulates the activities of multiple pore-forming alpha subunits, such as SCN1A, SCN2A, SCN3A, SCN4A, SCN5A and SCN10A (the  β1 and β1B subunits) may be targets to treat and understand arrhythmias (Williams et al. 2024). A rare noncoding enhancer variant in SCN5A contributes to a high prevalence of Brugada Syndrome (Walsh et al. 2025).