Hydrogen Ion/Peptide Transporter 2 (HPEPT2)

This transporter, SLC15A2, belongs to the same gene family as SLC15A1, the proton-coupled peptide transporter found in the small intestine.The SLC15A2 cDNA encodes a predicted 729-amino acid protein that contains 12 transmembrane domains and a long hydrophilic segment between transmembrane domains 9 and 10.

The amino acid sequence of SLC15A2 shows 50% identity and 70% similarity with that of SLC15A1. Functional expression of the SLC15A2 cDNA in HeLa cells resulted in the induction of a proton-dependent transport system that was able to transport dipeptides, tripeptides, and beta-lactam antibiotics; free amino acids were not accepted as substrates. RT-PCR showed that SLC15A2 is expressed in kidney but not in intestine.