title: mRNA distribution and membrane localization of the OAT-K1 organic anion transporter in rat renal tubules.
abstract: OAT-K1, a renal organic anion transporter, which mediates methotrexate uptake, was analyzed for mRNA distribution along microdissected nephron segments and the immunolocalization in isolated plasma membranes from rat kidney. By using a reverse transcription-coupled PCR, OAT-K1 mRNA was detected predominantly in the superficial and juxtamedullary proximal straight tubules. Western blotting with antiserum for OAT-K1 revealed that the transporter protein with the apparent molecular mass of 40 kDa was expressed exclusively in the brush-border membranes from rat kidney. These findings suggest that the OAT-K1 is localized in the brush-border membranes of the renal proximal straight tubules.
authors.affiliation: Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Sakyo-ku, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Masuda
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: H
authors.initials: H
authors.lastname: Nonoguchi
authors.forename: K
authors.initials: K
authors.lastname: Tomita
authors.forename: K
authors.initials: K
authors.lastname: Inui
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000838:Anions; D001692:Biological Transport; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification*; D004210:Dissection; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000737:chemistry; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification*; D008727:Methotrexate / Q000378:metabolism; D008871:Microvilli / Q000737:chemistry*; D008969:Molecular Sequence Data; D009399:Nephrons / Q000737:chemistry*; D027361:Organic Anion Transporters; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000302:isolation & purification*; D051381:Rats
chemical_list: D000838:Anions; D002352:Carrier Proteins; D008565:Membrane Proteins; D027361:Organic Anion Transporters; D012333:RNA, Messenger; C101140:Slc21a4 protein, rat; D008727:Methotrexate