Electroneutral Na(+) /H(+) antiporter that extrudes Na(+) in exchange for external protons driven by the inward sodium ion chemical gradient, protecting cells from acidification that occurs from metabolism (     , ). Exchanges intracellular H(+) ions for extracellular Na(+) in 1:1 stoichiometry (By similarity). Plays a key role in maintening intracellular pH neutral and cell volume, and thus is important for cell growth, proliferation, migration and survival ( , ). In addition, can transport lithium Li(+) and functions also as a Na(+)/Li(+) antiporter . SLC9A1 also functions in membrane anchoring and organization of scaffolding complexes that coordinate signaling inputs .
Subcellular locations: Cell membrane, Basolateral cell membrane
Localized basolaterally in every epithelial cell, except in the choroid plexus where SLC9A1 is expressed luminally.
Kidney and intestine.