The protein encoded by this gene is a system N sodium-coupled amino acid transporter. The encoded protein transports glutamine, asparagine, histidine, serine, alanine, and glycine across the cell membrane, but does not transport charged amino acids, imino acids, or N-alkylated amino acids. Alternative splicing results in multiple transcript variants, but the full-length nature of some of these variants has not been determined. [provided by RefSeq, Aug 2013]