Amino acid-proton symporter. Stereospecific transporter with a broad specificity for glutamate, aspartate and neutral and acidic amino acids. Expressed in flower buds, siliques, developing seeds and funiculi. Found in young seeds 2 to 5 days after fertilization, but not expressed in mature seeds. Reduced seed number and silique size correlated with a specifically altered amino acid composition of young siliques. Belongs to the amino acid/polyamine transporter 2 family. Amino acid/auxin permease (AAAP) (TC 2.A.18.2) subfamily.