|Name:||solute carrier family 36 (proton/amino acid symporter), member 2|
|Aliases:||PAT2, tramdorin, TRAMD1|
|PubMed (11959859):|| Boll M, Foltz M, Rubio-Aliaga I, Kottra G, Daniel H. Functional characterization of two novel mammalian electrogenicproton-dependent amino acid cotransporters.J Biol Chem. 2002 Jun 21;277(25):22966-73. Epub 2002 Apr 16. PMID: 11959859 [PubMed - indexed for MEDLINE]|
We cloned two cDNAs encoding proton/amino acid cotransporters, designated as mPAT1 and mPAT2, from murine tissues. They were identified by sequence similarity to the amino acid/auxin permease family member of lower eukaryotes. We functionally characterized both transporters by flux studies and electrophysiology after expression in Xenopus laevis oocytes. Both mPAT1 and mPAT2 induced a pH-dependent electrogenic transport activity for small amino acids (glycine, alanine, and proline) that is altered by membrane potential. Direct evidence for amino acid/H(+)-symport was shown by intracellular acidification, and a flux coupling stoichiometry for proline/H(+)-symport of 1:1 was determined for both transporters. Besides small apolar L-amino acids, the transporters also recognize their D-enantiomers and selected amino acid derivatives such as gamma-aminobutyric acid. The mPAT1 transporter, the murine orthologue of the recently cloned rat LYAAT-1 transporter, can be considered as a low affinity system when compared with mPAT2. The mRNA of mPAT1 is highly expressed in small intestine, colon, kidney, and brain; the mPAT2-mRNA is mainly found in heart and lung. Phenotypically, the PAT1 transporter possesses the same functional characteristics as the previously described proton-dependent amino acid transport process in apical membranes of intestinal and renal epithelial cells.