mRNA distribution and membrane localization of the OAT-K1 organic anion transporter in rat renal tubules

FEBS Lett. 1997 Apr 28;407(2):127-31. doi: 10.1016/s0014-5793(97)00314-1.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Anions
  • Biological Transport
  • Blotting, Western
  • Carrier Proteins / genetics
  • Carrier Proteins / isolation & purification*
  • Dissection
  • In Vitro Techniques
  • Kidney Tubules, Proximal / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / isolation & purification*
  • Methotrexate / metabolism
  • Microvilli / chemistry*
  • Molecular Sequence Data
  • Nephrons / chemistry*
  • Organic Anion Transporters*
  • Polymerase Chain Reaction
  • RNA, Messenger / isolation & purification*
  • Rats


  • Anions
  • Carrier Proteins
  • Membrane Proteins
  • Organic Anion Transporters
  • RNA, Messenger
  • Slc21a4 protein, rat
  • Methotrexate