Involved in pH regulation to eliminate acids generated by active metabolism or to counter adverse environmental conditions. Major proton extruding system driven by the inward sodium ion chemical gradient. Plays an important role in signal transduction.
Belongs to the monovalent cation:proton antiporter 1 (CPA1) transporter (TC 2.A.36) family.
Phosphorylated by PKA, which inhibits activity.
Membrane. In intestinal epithelial cells, localizes to the ileal brush border.