Multidrug efflux pump that functions as a H(+)/organic cation antiporter. Plays a physiological role in the excretion of cationic compounds including endogenous metabolites, drugs, toxins through the kidney and liver, into urine and bile respectively. Mediates the efflux of endogenous compounds such as creatinine, vitamin B1/thiamine, agmatine and estrone-3-sulfate. May also contribute to regulate the transport of cationic compounds in testis across the blood-testis-barrier.
Subcellular locations: Cell membrane, Apical cell membrane
Localizes to the plasma membrane; at the brush border membranes of the proximal tubules (kidney) and at the bile caniculi (liver).