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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1999-4-20
pubmed:databankReference
pubmed:abstractText
We have isolated a cDNA coding a new organic anion transporter, OAT-K2, expressed specifically in rat kidney. The OAT-K2 cDNA had an open reading frame encoding a 498-amino acid protein (calculated molecular mass of 55 kDa) that shows 91% identity with the rat kidney-specific organic anion transporter, OAT-K1. Reverse transcription-coupled polymerase chain reaction analyses revealed that the OAT-K2 mRNA was expressed predominantly in the proximal convoluted tubules, proximal straight tubules, and cortical collecting ducts. When expressed in Xenopus oocytes, OAT-K2 stimulated the uptake of hydrophobic organic anions, such as taurocholate, methotrexate, folate, and prostaglandin E2, although its homolog OAT-K1 transported methotrexate and folate, but not taurocholate and prostaglandin E2. In MDCK cells stably transfected with the OAT-K1 and OAT-K2 cDNAs, each transporter was localized functionally to the apical membranes and showed transport activity similar to that in the oocyte. Moreover, the efflux of preloaded taurocholate was also enhanced across the apical membrane in OAT-K2 transfectant. The taurocholate transport by OAT-K2-expressing cells showed saturability (Km = 10.3 microM). Several organic anions, bile acids, cardiac glycosides, and steroids had potent inhibitory effects on the OAT-K2-mediated taurocholate transport in the transfectant. These findings suggest that the OAT-K2 participates in epithelial transport of hydrophobic anionic compounds in the kidney.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0026-895X
pubmed:author
pubmed:issnType
Print
pubmed:volume
55
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
743-52
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10101033-Amino Acid Sequence, pubmed-meshheading:10101033-Animals, pubmed-meshheading:10101033-Base Sequence, pubmed-meshheading:10101033-Carrier Proteins, pubmed-meshheading:10101033-Cloning, Molecular, pubmed-meshheading:10101033-DNA, Complementary, pubmed-meshheading:10101033-Kidney, pubmed-meshheading:10101033-Male, pubmed-meshheading:10101033-Membrane Proteins, pubmed-meshheading:10101033-Molecular Sequence Data, pubmed-meshheading:10101033-Multidrug Resistance-Associated Proteins, pubmed-meshheading:10101033-Oocytes, pubmed-meshheading:10101033-Organic Anion Transporters, pubmed-meshheading:10101033-RNA, Messenger, pubmed-meshheading:10101033-Rats, pubmed-meshheading:10101033-Rats, Wistar, pubmed-meshheading:10101033-Sequence Homology, Amino Acid, pubmed-meshheading:10101033-Sequence Homology, Nucleic Acid, pubmed-meshheading:10101033-Tissue Distribution, pubmed-meshheading:10101033-Transfection, pubmed-meshheading:10101033-Xenopus laevis
pubmed:year
1999
pubmed:articleTitle
Cloning and functional characterization of a new multispecific organic anion transporter, OAT-K2, in rat kidney.
pubmed:affiliation
Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't