SLC38A4 is found predominantly in liver and transports both cationic and neutral amino acids. The transport of cationic amino acids by SLC38A4 is Na(+) and pH independent, while the transport of neutral amino acids is Na(+) and pH dependent (Hatanaka et al., 2001 [PubMed 11342143]).[supplied by OMIM, Mar 2008].
Function: Sodium-dependent amino acid transporter. Mediates electrogenic symport of neutral amino acids and sodium ions. Has a broad specificity, with a preference for Ala, followed by His, Cys, Asn, Ser, Gly, Val, Thr, Gln and Met. May mediate sodium-independent transport of cationic amino acids, such as Arg and Lys. Amino acid uptake is pH-dependent, with low transport activities at pH 6.5, intermediate at pH 7.0 and highest between pH 7.5 and 8.5.