TY - JOUR
T1 - A novel human amino acid transporter, hNAT3
T2 - cDNA cloning, chromosomal mapping, genomic structure, expression, and functional characterization
AU - Gu, Sumin
AU - Adan-Rice, Delhi
AU - Leach, Robin J.
AU - Jiang, Jean X.
N1 - Funding Information:
We are grateful to J. M. Chirgwin at UTHSCSA for generously providing human cell lines. We also thank X. T. Reveles, Director of the UTHSCSA Genetics Resource Core, for assistance with FISH analysis, and V. C. Frohlich, Director of the Confocal Imaging Core Facility, for assistance with imaging. The work is supported by a National Institutes of Health grant (to J.X.J.) and a San Antonio Cancer Institute Shared Resource grant (to R.J.L.).
PY - 2001/6/15
Y1 - 2001/6/15
N2 - Amino acid transporters are proteins that transport amino acids across the membrane. We report here the isolation and characterization of a novel human cDNA clone encoding a protein of 547 amino acids. This protein shares ∼50% amino acid sequence homology with the amino acid transporters mouse mNAT and its orthologs, rat SN1 and human g17, and mouse GlnT/ATA1 and ATA2. Expression of this cRNA in Xenopus oocytes revealed that the strongest transport activities were specific for L-alanine. In addition, hNAT3 is a Na+- and pH-dependent, low-affinity transporter and partially tolerates substitution of Na+ by Li+. Since this protein has sequence and functional similarities to the previously identified system N amino acid transporters, we named this protein hNAT3. The genomic DNA sequence encoding the transcript of hNAT3 spans over 14 kb with 16 exons and 15 introns. Using fluorescence in situ hybridization, we mapped the hNAT3 gene to human chromosome 12q12-q13. By RT-PCR of embryonic and adult human tissues, hNAT3 was detected to be predominately expressed in the liver and to a much lesser extent in the muscle, kidney, and pancreas. The data obtained in this study are likely to offer critical clues for identification of amino acid transporter-associated diseases.
AB - Amino acid transporters are proteins that transport amino acids across the membrane. We report here the isolation and characterization of a novel human cDNA clone encoding a protein of 547 amino acids. This protein shares ∼50% amino acid sequence homology with the amino acid transporters mouse mNAT and its orthologs, rat SN1 and human g17, and mouse GlnT/ATA1 and ATA2. Expression of this cRNA in Xenopus oocytes revealed that the strongest transport activities were specific for L-alanine. In addition, hNAT3 is a Na+- and pH-dependent, low-affinity transporter and partially tolerates substitution of Na+ by Li+. Since this protein has sequence and functional similarities to the previously identified system N amino acid transporters, we named this protein hNAT3. The genomic DNA sequence encoding the transcript of hNAT3 spans over 14 kb with 16 exons and 15 introns. Using fluorescence in situ hybridization, we mapped the hNAT3 gene to human chromosome 12q12-q13. By RT-PCR of embryonic and adult human tissues, hNAT3 was detected to be predominately expressed in the liver and to a much lesser extent in the muscle, kidney, and pancreas. The data obtained in this study are likely to offer critical clues for identification of amino acid transporter-associated diseases.
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U2 - 10.1006/geno.2001.6567
DO - 10.1006/geno.2001.6567
M3 - Article
C2 - 11414754
AN - SCOPUS:0035874932
SN - 0888-7543
VL - 74
SP - 262
EP - 272
JO - Genomics
JF - Genomics
IS - 3
ER -