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Primary structure and functional expression of a cDNA encoding the bile canalicular, purine-specific Na(+)-nucleoside cotransporter.
- Source :
- Journal of Biological Chemistry; June 1995, Vol. 270 Issue: 23 p13596-9, 4p
- Publication Year :
- 1995
-
Abstract
- We previously characterized a purine-specific Na(+)-nucleoside cotransport system in bile canalicular membrane. The function of this transport system may be related to conserving nucleosides and preventing cholestasis. We report here the isolation of a cDNA encoding a Na(+)-dependent nucleoside transporter from rat liver using an expression cloning strategy. The substrate specificities and kinetic characteristics of the cloned cotransporter are consistent with the properties of the Na(+)-dependent, purine-selective nucleoside transporter in bile canalicular membranes. The nucleotide sequence predicts a protein of 659 amino acids (72 kDa) with 14 putative membrane-spanning domains. Northern blot analysis showed that the transcripts are present in liver and several other tissues. Data base searches indicate significant sequence similarity to the pyrimidine-selective nucleoside transporter (cNT1) of rat jejunum. Although these two subtypes of Na(+)-nucleoside cotransporter have different substrate specificities and tissue localizations, they are members of a single gene family.
Details
- Language :
- English
- ISSN :
- 00219258 and 1083351X
- Volume :
- 270
- Issue :
- 23
- Database :
- Supplemental Index
- Journal :
- Journal of Biological Chemistry
- Publication Type :
- Periodical
- Accession number :
- ejs7056121