Transports arginine, lysine, homoarginine, methylarginine and, to a much lesser extent, ornithine and histidine. Does not transport carnitine nor acylcarnitines. Functions by both counter-exchange and uniport mechanisms (By similarity). Can restore ornithine transport in cells lacking the primary mitochondrial ornithine transporter SLC25A15 (PubMed:19287344). Widely expressed, with highest levels in the brain, including cortex, cerebellum, hippocampus and hypothalamus, and moderate levels in liver, kidney, heart and testis. By partial hepactectomy and fasting. Belongs to the mitochondrial carrier (TC 2.A.29) family. Was initially proposed to transport palmitoylcarnitine, based on complementation experiments in yeast mutants lacking CRC1 and CIT2 and release of radiolabeled carnitine from mitochondria incubated with radiolabeled palmitoylcarnithine (PubMed:12882971). Later experiments done primarily with human indicate the protein functions instead as transporter of basic amino acids.