A novel human organic anion transporting polypeptide localized to the basolateral hepatocyte membrane.

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Konig J, Cui Y, Nies AT, Keppler D

A novel human organic anion transporting polypeptide localized to the basolateral hepatocyte membrane.

Am J Physiol Gastrointest Liver Physiol. 2000 Jan;278(1):G156-64.

PubMed ID

10644574 [ View in PubMed

]

Abstract

We cloned and expressed a new organic anion transporting polypeptide (OATP), termed human OATP2, (OATP-C, LST-1; symbol SLC21A6), involved in the uptake of various lipophilic anions into human liver. The cDNA encoding OATP2 comprised 2073 base pairs, corresponding to a protein of 691 amino acids, which were 44% identical to the known human OATP. An antibody directed against the carboxy terminus localized OATP2 to the basolateral membrane of human hepatocytes. Northern blot analysis indicated a strong expression of OATP2 only in human liver. Transport mediated by recombinant OATP2 and its localization were studied in stably transfected Madin-Darby canine kidney strain II (MDCKII) and HEK293 cells. Confocal microscopy localized recombinant OATP2 protein to the lateral membrane of MDCKII cells. Substrates included 17beta-glucuronosyl estradiol, monoglucuronosyl bilirubin, dehydroepiandrosterone sulfate, and cholyltaurine. 17beta-Glucuronosyl estradiol was a preferred substrate, with a Michaelis-Menten constant value of 8.2 microM; its uptake was Na(+) independent and was inhibited by sulfobromophthalein, with a inhibition constant value of 44 nM. Our results indicate that OATP2 is important for the uptake of organic anions, including bilirubin conjugates and sulfobromophthalein, in human liver.

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Cholic Acid	Solute carrier organic anion transporter family member 1B1	Protein	Humans	Unknown	Substrate Inhibitor Inducer	Details

Polypeptides

Name	UniProt ID
Solute carrier organic anion transporter family member 1B1	Q9Y6L6	Details