Heterodimer with SLC3A2, that functions as an antiporter which operates as an efflux route by exporting cationic amino acids such as L-arginine from inside the cells in exchange with neutral amino acids like L-leucine, L-glutamine and isoleucine, plus sodium ions and may participate in nitric oxide synthesis (    ). Also exchanges L-arginine with L-lysine in a sodium-independent manner . The transport mechanism is electroneutral and operates with a stoichiometry of 1:1 . Contributes to ammonia-induced increase of L-arginine uptake in cerebral cortical astrocytes leading to ammonia-dependent increase of nitric oxide (NO) production via inducible nitric oxide synthase (iNOS) induction, and protein nitration (By similarity). May mediate transport of ornithine in retinal pigment epithelial (RPE) cells . May also transport glycine betaine in a sodium dependent manner from the cumulus granulosa into the enclosed oocyte (By similarity).
Subcellular locations: Cell membrane
Expressed in normal fibroblasts and those from LPI patients . Also expressed in HUVECs, monocytes, RPE cells, and various carcinoma cell lines (  ). Expressed in brain, heart, testis, kidney, small intestine and parotis . Highly expressed in T lymphocytes .