Cloning and expression of a b0,+-like amino acid transporter functioning asa heterodimer with 4F2hc-instead of rBAT. A new candidate gene for cystinuria

D. Prasanna Rajan, Ramesh Kekuda, Wei Huang, Haiping Wang, Lawrence D Devoe, Frederick H. Leibach, Puttur D Prasad, Vadivel Ganapathy

Research output: Contribution to journalArticle

59 Scopus citations

Abstract

We have cloned a transporter protein from rabbit small intestine, which, when coexpressed with the 4F2 heavy chain (4F2hc) in mammalian cells, induces a b0,+-like amino acid transport activity. This protein (4F2-lc6 for the sixth member of the 4F2 light chain family) consists of 487 amino acids and has 12 putative transmembrane domains. At the level of amino acid sequence, 4F2-lc6 shows significant homology (44% identity) to the other five known members of the 4F2 light chain family, namely LAT1 (4F2-lc1), y+LAT1 (4F2- lc2), y+LAT2 (4F2-lc3), xCT (4F2-lc4), and LAT2 (4F2-lc5). The 4F2hc/4F2-lc6 complex-mediated transport process is Na+-independent and exhibits high affinity for neutral and cationic amino acids and cystine. These characteristics are similar to those of the b0,+-like amino acid transport activity previously shown to be associated with rBAT (protein related to b0,+ amino acid transport system). However, the newly cloned 4F2-lc6 does not interact with rBAT. This is the first report of the existence of ab0,+ like amino acid transport process that is independent of rBAT. 4F2-lc6 is expressed predominantly in the small intestine and kidney. Based on the characteristics of the transport process mediated by the 4F2hc/4F2-lc6 complex and the expression pattern of 4F2-lc6 in mammalian tissues, we suggest that 4F2-lc6 is a new candidate gene for cystinuria.

Original languageEnglish (US)
Pages (from-to)29005-29010
Number of pages6
JournalJournal of Biological Chemistry
Volume274
Issue number41
DOIs
StatePublished - Oct 8 1999

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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