Epithelial sodium channels

Epithelial sodium channels (ENaCs), also known as amiloride-sensitive sodium channels, are voltage-independent membrane-bound ion channels that are selectively permeable to sodium ions.  ENaCs exist as heterotrimers composed of three homologous subunits, α or δ, β, and γ, that contain two membrane-spanning segments per subunit and are responsible for the detection of a variety of sensory stimuli.  ENaCs are located in the apical membrane of epithelial cells, in particular in the kidney tubules, the lung and respiratory tract, skin, the male and female reproductive tracts, sweat and salivary glands, placenta and the colon, and play a crucial role in sodium ion transport and fluid reabsorption.  ENaCs are essential for the clearance of respiratory airways, transport of germ cells, fertilisation, implantation, and cell migration, and in the brain have an important role in the regulation of blood pressure.

Further reading

Hanukoglu and Hanukoglu (2016) Epithelial sodium channel (ENaC) family: Phylogeny, structure-function, tissue distribution, and associated inherited diseases. Gene 579(2) 95 PMID: 26772908

Baldin et al (2020) Epithelial Na+ Channel (ENaC) Formed by One or Two Subunits Forms Functional Channels That Respond to Shear Force. Front Physiol. 11:141 PMID: 32256376

Noreng et al (2020) Molecular principles of assembly, activation, and inhibition in epithelial sodium channel. Elife 9:e59038 PMID: 32729833

IUPHAR/BPS Guide to Pharmacology - Epithelial sodium channels