Functions as a permease involved in the transport of the cationic amino acids (L-arginine, L-lysine, L-ornithine and L-homoarginine); the affinity for its substrates differs between isoforms created by alternative splicing (, ). May play a role in classical or alternative activation of macrophages via its role in arginine transport (By similarity).
Functions as a permease that mediates the transport of the cationic amino acids (L-arginine, L-lysine, L-ornithine and L-homoarginine). Shows a much higher affinity for L-arginine and L-homoarginine than isoform 2.
Functions as a low-affinity, high capacity permease involved in the transport of the cationic amino acids (L-arginine, L-lysine, L-ornithine and L-homoarginine).
Subcellular locations: Cell membrane
Expressed at high levels in the skeletal muscle, placenta and ovary. Expressed at intermediate levels in the liver and pancreas and at low levels in the kidney and heart.