RT Journal Article SR Electronic T1 Molecular Cloning and Functional Characterization of a Polyspecific Organic Anion Transporter from Caenorhabditis elegans JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 596 OP 603 VO 291 IS 2 A1 George, Ronald L. A1 Wu, Xiang A1 Huang, Wei A1 Fei, You-Jun A1 Leibach, Frederick H. A1 Ganapathy, Vadivel YR 1999 UL http://jpet.aspetjournals.org/content/291/2/596.abstract AB We have cloned a polyspecific organic anion transporter fromCaenorhabditis elegans and elucidated its functional characteristics. The C. elegans anion transporter (CeOAT1) codes for a protein of 526 amino acids containing 12 putative transmembrane domains. It exhibits significant homology at the level of amino acid sequence to the C. elegans organic cation transporter and to the mammalian organic cation and anion transporters. The function of CeOAT1 was investigated by expressing the transporter heterologously in mammalian cells. CeOAT1 transportsp-aminohippurate (PAH) in a Na+-independent manner. The transport mechanism appears to involve anion exchange because CeOAT1-mediated PAH transport is stimulated by a cell-to-medium concentration gradient of α-ketoglutarate or fumarate generated by coexpression in the cells of a mammalian Na+-coupled dicarboxylate transporter. CeOAT1 exhibits broad specificity, accepting anions such as folate, indomethacin, furosemide, probenecid, and benzylpenicillin as substrates. The Michaelis-Menten constant for the prototypical organic anion PAH is 0.43 ± 0.07 mM. This constitutes the first report of the molecular and functional identification of a polyspecific organic anion transporter in C. elegans. The American Society for Pharmacology and Experimental Therapeutics