Exp Mol Med.  2007 Dec;39(6):787-795.

Identification of a kidney-specific mouse organic cation transporter like-1 (mOCTL1)

• Lee WK
• Hwang JS
• Yun CH
• Cha SH

Abstract

Organic ion transporters are expressed in various tissues that transport endogenous and exogenous compounds including their metabolites. There are organic anion transporter (OAT), organic cation transporter (OCT), organic anion transporter like protein (OATLP) and organic cation transporter like (OCTL). Considering the variety of charged organic ionic compounds, the existence of numerous isoforms of organic ion transporters can be assumed. In the present study, we have searched for a new isoform in the expressed sequence tag (EST) database using human organic anion transporter 4 (hOAT4) amino acid sequence as a "query". We found a candidate clone (BC021449) from the mouse kidney cDNA library. This clone was identified as an ortholog of ORCTL3 or OCTL-1. The mOCTL1 cDNA consists of 2016 base pairs encoding 551 amino acid residues with 12 putative transmembrane domains. The deduced amino acid sequence of mOCTL1 showed 35 to 40% identity to those of the other members of the OATs and OCTs. According to the tissue distribution, examined by Northern blot analysis, about a 2.4-kb transcript of mOCTL1 was observed in the kidney. About a 90-kDa band was detected when Western blot analysis in the mouse kidney was done by using antibody against synthesized oligopeptide of mOCTL1. The immunohistochemical result showed that mOCTL1 was stained at the glomerulus (the parietal epithelial cells and podocytes), pars recta of proximal tubule, distal convoluted tubules, connecting tubules and collecting tubules. From these results, we conclude that mOCTL1 may be a candidate for an organic ion transporter isoform in the mouse kidney.

Keyword

kidney; immunohistochemistry; organic anion transporters; organic cation transport proteins

MeSH Terms

Amino Acid Sequence
Animals
Blotting, Western
Gene Library
Humans
Immunohistochemistry
Kidney/*metabolism
Mice
Molecular Sequence Data
Organ Specificity
Organic Cation Transport Proteins/genetics/*isolation & purification
Organic Cation Transporter 1/genetics/*isolation & purification
Protein Isoforms/isolation & purification