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 (PubMed:10903140, PubMed:11311135, PubMed:14603368, PubMed:15756301, PubMed:16785209, PubMed:17329401, PubMed:19562367, PubMed:31705628, PubMed:9829974). Also exchanges L-arginine with L-lysine in a sodium-independent manner (PubMed:10903140). The transport mechanism is electroneutral and operates with a stoichiometry of 1:1 (PubMed:10903140). 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 (PubMed:17197568). May also transport glycine betaine in a sodium dependent manner from the cumulus granulosa into the enclosed oocyte (By similarity).
