Amino acid-proton symporter. Stereospecific transporter with a broad specificity for glutamate and both neutral and basic amino acids. Reduced affinities for asparagine and valine. High affinity transport of the cationic amino acids arginine and lysine, but not of histidine. Inhibited by 2,4-dinitrophenol. Expressed in leaves, stems, roots, siliques and flowers. High expression in source leaves, but almost undetected in sink leaves. No visible phenotype, but decreased uptake of L-arginine and L-lysine. Basic amino acids are transported in their fully ionized form. Belongs to the amino acid/polyamine transporter 2 family. Amino acid/auxin permease (AAAP) (TC 2.A.18.2) subfamily.