Uniporter that mediates the transport of the stereospecific L-phenylalanine, L-methionine and L-branched-chain amino acids, between the extracellular space and the cytoplasm and may control the transepithelial (re)absorption of neutral amino acid in kidney and small intestine (PubMed:15659399, PubMed:30379325). The transport activity is mediated through facilitated diffusion and is sodium ions-, chloride ions- and pH-independent (PubMed:15659399).