Primary structure, functional characteristics and tissue expression pattern of human ATA2, a subtype of amino acid transport system A

Takahiro Hatanaka, Wei Huang, Haiping Wang, Mitsuru Sugawara, Puttur D. Prasad, Frederick H. Leibach, Vadivel Ganapathy

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We report here on the primary structure and functional characteristics of the protein responsible for the system A amino acid transport activity that is known to be expressed in most human tissues. This transporter, designated ATA2 for amino acid transporter A2, was cloned from the human hepatoma cell line HepG2. Human ATA2 (hATA2) consists of 506 amino acids and exhibits a high degree of homology to rat ATA2. hATA2-specific mRNA is ubiquitously expressed in human tissues. When expressed in mammalian cells, hATA2 mediates Na+-dependent transport of α-(methylamino)isobutyric acid, a specific model substrate for system A. The transporter is specific for neutral amino acids. It is pH-sensitive and Li+-intolerant. The Na+:amino acid stoichiometry is 1:1. (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)1-6
Number of pages6
JournalBiochimica et Biophysica Acta - Biomembranes
Issue number1
StatePublished - Jul 31 2000



  • Amino acid transport
  • Human
  • Primary structure
  • Stoichiometry
  • Substrate specificity
  • System A

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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