| First Author | Boll M | Year | 2002 |
| Journal | J Biol Chem | Volume | 277 |
| Issue | 25 | Pages | 22966-73 |
| PubMed ID | 11959859 | Mgi Jnum | J:78797 |
| Mgi Id | MGI:2386191 | Doi | 10.1074/jbc.M200374200 |
| Citation | Boll M, et al. (2002) Functional characterization of two novel mammalian electrogenic proton-dependent amino acid cotransporters. J Biol Chem 277(25):22966-73 |
| abstractText | 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. |
