cDNA cloning, functional characterization, and tissue distribution of an alternatively spliced variant of organic cation transporter hOCT2 predominantly expressed in the human kidney.
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Urakami Y, Akazawa M, Saito H, Okuda M, Inui K
cDNA cloning, functional characterization, and tissue distribution of an alternatively spliced variant of organic cation transporter hOCT2 predominantly expressed in the human kidney.
J Am Soc Nephrol. 2002 Jul;13(7):1703-10.
- PubMed ID
- 12089365 [ View in PubMed]
- Abstract
A cDNA coding a novel organic cation transporter, hOCT2-A, was isolated from human kidney. The hOCT2-A cDNA is an alternatively spliced variant of hOCT2 with an insertion of 1169 bp. The open reading frame encodes a 483-amino acid protein that has 81% amino acid identity with hOCT2. From hydropathy analysis, hOCT2-A is predicted to have nine transmembrane domains. hOCT2-A mRNA is expressed mainly in kidney and weakly in brain, liver, colon, skeletal muscle, bone marrow, spinal cord, testis, and placenta. When expressed in HEK293 cells, hOCT2-A stimulated the uptake of tetraethylammonium (TEA) in an electrogenic manner. The transport of TEA by hOCT2-A-transfected cells was saturable with the apparent Km value of 63 microM. hOCT2-A stimulated the uptake of TEA, 1-methyl-4-phenylpyridinium, and cimetidine as well as did hOCT2. The uptake of guanidine and choline by hOCT2-transfected cells also increased markedly but not that by hOCT2-A-transfected cells. The uptake of TEA mediated by hOCT2-A but not by hOCT2 was inhibited significantly by organic cations such as procainamide, N-acetylprocainamide, and levofloxacin, indicating that hOCT2-A differs from hOCT2 in its affinity for several compounds. These findings suggested that hOCT2-A contributes to the renal clearance of endogenous and exogenous organic cations.
DrugBank Data that Cites this Article
- Drug Transporters
- Polypeptides
Name UniProt ID Solute carrier family 22 member 2 O15244 Details