Cloning and functional expression of ATA1, a subtype of amino acid transporter A, from human placenta

Biochem Biophys Res Commun. 2000 Jul 14;273(3):1175-9. doi: 10.1006/bbrc.2000.3061.

Abstract

This report describes the primary structure and functional characteristics of human ATA1, a subtype of the amino acid transport system A. The human ATA1 cDNA was isolated from a placental cDNA library. The cDNA codes for a protein of 487 amino acids with 11 putative transmembrane domains. The transporter mRNA ( approximately 9.0 kb) is expressed most prominently in the placenta and heart, but detectable level of expression is evident in other tissues including the brain. When expressed heterologously in mammalian cells, the cloned transporter mediates Na(+)-coupled transport of the system A-specific model substrate alpha-(methylamino)isobutyric acid. The transport process is saturable with a Michaelis-Menten constant of 0. 89 +/- 0.12 mM. The Na(+):amino acid stoichiometry is 1:1 as deduced from the Na(+)-activation kinetics. The transporter is specific for small short-chain neutral amino acids. The gene for the transporter is located on human chromosome 12.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Transport Systems
  • Base Sequence
  • Blotting, Northern
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism
  • DNA, Complementary
  • Female
  • Humans
  • Molecular Sequence Data
  • Placenta / metabolism*
  • RNA, Messenger / genetics
  • Sequence Homology, Amino Acid

Substances

  • Amino Acid Transport Systems
  • Carrier Proteins
  • DNA, Complementary
  • RNA, Messenger