High impact information on SLC15A3

• [(3)H]Carnosine uptake in neonatal rat astrocytes was inhibited by dipeptides but not by histidine (a substrate for the peptide/histidine transporters PHT1 and PHT2) and also showed saturable transport (V(max)=447+/-23 pmol/mg/min, K(m)=43+/-5.5 muM) [1].
• Recently, several new POT members, including Peptide/Histidine Transporter 1 (PHT1) and Peptide/Histidine Transporter 2 (PHT2) and their splice variants have been identified [2].
• In contrast, PEPT2 and PHT2 were expressed only in bovine and human retina, and PEPT1 could not be detected [3].
• In contrast, PTR3 and HPT-1 were widely expressed in the human GIT, with predominant expression in the different regions of the colon [4].
• Using sequence-specific primers designed to amplify regions of PepT1, PTR3, PHT1, and HPT-1, we were able to identify the expression of mRNA for each of these transporters in human cDNA panels (Clontech, Palo Alto, CA), the rat GIT, and in Caco-2 cDNA libraries by the polymerase chain reaction (PCR) and Southern Blot analysis [4].

Biological context of SLC15A3

• This contig served to identify a PAC clone containing deduced exons and introns of the likely human orthologue (termed hPHT2) [5].

Anatomical context of SLC15A3

• PHT1 and PHT2 were shown to transport free histidine and certain di- and tripeptides, but it is not yet clear whether they are located on the plasma membrane or represent lysosomal transporters for the proton-dependent export of histidine and dipeptides from lysosomal protein degradation into the cytosol [6].
• Northern analyses with EST clones indicated that hPHT1 is primarily expressed in skeletal muscle and spleen, whereas hPHT2 is found in spleen, placenta, lung, leukocytes, and heart [5].

Analytical, diagnostic and therapeutic context of SLC15A3

• The loci PTR3, PTR5, and PTR7 were found to be the most informative for genetic fingerprinting and differentiation of the clones [7].

References