Functional expression of pig renal organic anion transporter 3 (pOAT3).
With the cloning of pig renal organic anion transporter 1 (pOAT1) (Biochimie 84 (2002) 1219) we set up a model system for comparative studies of cloned and natively isolated membrane located transport proteins. Meanwhile, another transport protein involved in p-aminohippurate (PAH) uptake on the basolateral side of the proximal tubule cells was identified, designated organic anion transporter 3 (OAT3). To explore the contribution of pOAT1 to the PAH clearance in comparison to OAT3, it was the aim of this study to extend our model by cloning of the pig ortholog of OAT3. Sequence comparisons of human organic anion transporter 3 (hOAT3) with the expressed sequence tag (EST) database revealed a clone and partial sequence of the pig renal organic anion transporter 3 (pOAT3) ortholog. Sequencing of the entire open reading frame resulted in a protein of 543 amino acid residues encoded by 1632 base pairs (EMBL Acc. No. AJ587003). It showed high homologies of 81%, 80%, 76%, and 77% to the human, rabbit, rat, and mouse OAT3, respectively. A functional characterization of pOAT3 in Xenopus laevis oocytes yielded an apparent Km (Kt) for [3H]estrone sulfate of 7.8 +/- 1.3 microM. Moreover, pOAT3 mediated [3H]estrone sulfate uptake was almost abolished by 0.5 mM of glutarate, dehydroepiandosterone sulfate, or probenecid consistent with the hallmarks of OAT3 function.
Hagos
Yohannes
Y
Zentrum für Physiologie und Pathophysiologie, Abt. Vegetative Physiologie, Humboldtallee 23, 37073 Göttingen, Germany. hagos@veg-physiol.med.uni-goettingen.de
Braun
Isabella M
IM
Krick
Wolfgang
W
Burckhardt
Gerhard
G
Bahn
Andrew
A
D000595:Amino Acid Sequence; D000818:Animals; D018076:DNA, Complementary; D019314:Dehydroepiandrosterone Sulfate / Q000494:pharmacology; D004970:Estrone / Q000031:analogs & derivatives* / Q000378:metabolism; D005977:Glutarates / Q000494:pharmacology; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D029362:Organic Anion Transporters, Sodium-Independent / Q000235:genetics* / Q000378:metabolism; D011339:Probenecid / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013552:Swine; D014528:Uricosuric Agents / Q000494:pharmacology; D014982:Xenopus laevis / Q000378:metabolism; D010130:p-Aminohippuric Acid / Q000493:pharmacokinetics
D018076:DNA, Complementary; D005977:Glutarates; D029362:Organic Anion Transporters, Sodium-Independent; D014528:Uricosuric Agents; C114338:organic anion transport protein 3; D004970:Estrone; D019314:Dehydroepiandrosterone Sulfate; D011339:Probenecid; C017296:estrone sulfate; D010130:p-Aminohippuric Acid