Functional characteristics and tissue distribution pattern of organic cation transporter 2 (OCTN2), an organic cation/carnitine transporter

Xiang Wu, Wei Huang, Puttur D. Prasad, Pankaj Seth, Deva P. Rajan, Frederick H. Leibach, Jinwen Chen, Simon J. Conway, Vadivel Ganapathy

Research output: Contribution to journalArticlepeer-review

295 Scopus citations

Abstract

We have demonstrated in the present study that novel organic cation transporter (OCTN) 2 is a transporter for organic cations as well as carnitine. OCTN2 transports organic cations without involving Na+, but it transports carnitine only in the presence of Na+. The ability to transport organic cations and carnitine is demonstrable with human, rat, and mouse OCTN2s. Na+ does not influence the affinity of OCTN2 for organic cations, but it increases the affinity severalfold for carnitine. The short-chain acyl esters of carnitine are also transported by OCTN2. Two mutations, M352R and P478L, in human OCTN2 are associated with loss of transport function, but the protein expression of these mutants is comparable to that of the wild-type human OCTN2. In situ hybridization in the rat shows that OCTN2 is expressed in the proximal and distal tubules and in the glomeruli in the kidney, in the myocardium, valves, and arterioles in the heart, in the labyrinthine layer of the placenta, and in the cortex, hippocampus, and cerebellum in the brain. This is the first report that OCTN2 is a Na+-independent organic cation transporter as well as a Na+-dependent carnitine transporter and that OCTN2 is expressed not only in the heart, kidney, and placenta but also in the brain.

Original languageEnglish (US)
Pages (from-to)1482-1492
Number of pages11
JournalJournal of Pharmacology and Experimental Therapeutics
Volume290
Issue number3
StatePublished - Sep 1999

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

Fingerprint Dive into the research topics of 'Functional characteristics and tissue distribution pattern of organic cation transporter 2 (OCTN2), an organic cation/carnitine transporter'. Together they form a unique fingerprint.

Cite this