SLC15 family of peptide transporters

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).


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The SLC15 family of peptide transporters may be divided on the basis of structural and functional differences into two subfamilies: SLC15A1 (PepT1) and SLC15A2 (PepT2) transport di- and tripeptides, but not amino acids, whereas SLC15A3 (PHT2) and SLC15A4 (PHT1) transport L-histidine and some di- and tripeptides [5]. The transporters are 12 TM proteins with intracellular termini and an extended extracellular loop at TM 9/10. The crystal structure of PepTSo (a prokaryote homologue of PepT1 and PepT2 from Shewanella oneidensis) confirms many of the predicted structural features of mammalian PepT1 and PepT2 [15].

PHT1 has been suggested to be intracellular [16], while PHT2 protein is located on lysosomes in transfected cells [4,11,18]. PHT1 is hypothesised to mediate efflux of bacterial-derived peptides into the cytosol perhaps in the colon where SLC15A4 mRNA expression is increased in inflammatory bowel disease [13]. Transport via PHT1 may be important in immune responses as both Toll-like receptor- and NOD1-mediated responses are reduced in PHT1 knockout mice or mouse strains expressing mutations in PHT1 [3,19].


PepT1 (Peptide transporter 1 / SLC15A1) Show summary »

PepT2 (Peptide transporter 2 / SLC15A2) Show summary »

PHT2 (Peptide transporter 3 / SLC15A3) Show summary »

PHT1 (Peptide transporter 4 / SLC15A4) Show summary »


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Further reading

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How to cite this family page

Database page citation:

SLC15 family of peptide transporters. Accessed on 23/03/2017. IUPHAR/BPS Guide to PHARMACOLOGY,

Concise Guide to PHARMACOLOGY citation:

Alexander SPH, Kelly E, Marrion N, Peters JA, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Southan C, Davies JA and CGTP Collaborators (2015) The Concise Guide to PHARMACOLOGY 2015/16: Transporters. Br J Pharmacol. 172: 6110-6202.