ENaC is localized to the apical side of polarized epithelial cells like those in the kidney, lung, and distal colon and is responsible for maintaining proper Na+ balance. This channel is formed by oligomerization of three subunits, α, β, and γ usually with the α2β1γ1 combination. In addition, the α subunit which is essential for channel activity undergoes phosphorylation in its C-terminal by SGK1 (serum and glucocorticoid-induced kinase 1) which is known to activate the channel at the plasma membrane
