Expression cloning and characterization of a renal organic anion transporter from winter flounder

The cDNA coding for a renal p-aminohippurate (PAH) transporter from winter flounder (Pseudopleuronectes americanus), designated fROAT, was cloned by functional expression in Xenopus laevis oocytes, fROAT is approximately 2.8 kbp in length and encodes a protein of 562 amino acids, related to the rat renal organic anion transporter ROAT1/OAT1 and the organic cation transporters OCT1 and OCT2, In oocytes, fROAT mediated probenecid-sensitive PAH uptake, with a K-m for PAH of about 20 mu M, and inhibited by external glutarate (GA) (1 mM). The functional characteristics suggest that fROAT is the basolateral PAH/dicarboxylate exchanger of the flounder kidney. (C) 1997 Federation of European Biochemical Societies.