Sodium permeable non-voltage-sensitive ion channel inhibited by the diuretic amiloride. Mediates the electrodiffusion of the luminal sodium (and water, which follows osmotically) through the apical membrane of epithelial cells. Plays an essential role in electrolyte and blood pressure homeostasis, but also in airway surface liquid homeostasis, which is important for proper clearance of mucus. Controls the reabsorption of sodium in kidney, colon, lung and eccrine sweat glands. Also plays a role in taste perception.
Subcellular locations: Apical cell membrane, Cell projection, Cilium, Cytoplasmic granule, Cytoplasm, Cytoplasmic vesicle, Secretory vesicle, Acrosome, Cell projection, Cilium, Flagellum
In the oviduct and bronchus, located on cilia in multi-ciliated cells. In endometrial non-ciliated epithelial cells, restricted to apical surfaces. In epidermis, located nearly uniformly in the cytoplasm in a granular distribution. In sebaceous glands, observed only in the cytoplasmic space in between the lipid vesicles. In eccrine sweat glands, mainly located at the apical surface of the cells facing the lumen. In skin, in arrector pili muscle cells and in adipocytes, located in the cytoplasm and colocalized with actin fibers. In spermatogonia, spermatocytes and round spermatids, located in the cytoplasm. Prior to spermiation, location shifts from the cytoplasm to the spermatid tail. In spermatozoa, localizes at the acrosome and the central region of the sperm flagellum.