Molecular biology and regulation of nucleoside and nucleobase transporter proteins in eukaryotes and prokaryotes.
The molecular cloning of cDNAs encoding nucleoside transporter proteins has greatly advanced understanding of how nucleoside permeants are translocated across cell membranes. The nucleoside transporter proteins identified thus far have been categorized into five distinct superfamilies. Two of these superfamilies, the equilibrative and concentrative nucleoside transporters, have human members and these will be examined in depth in this review. The human equilibrative nucleoside transporters translocate nucleosides and nucleobases bidirectionally down their concentration gradients and are important in the uptake of anticancer and antiviral nucleoside drugs. The human concentrative nucleoside transporters cotranslocate nucleosides and sodium unidirectionally against the nucleoside concentration gradients and play a vital role in certain tissues. The regulation of nucleoside and nucleobase transporters is being studied more intensely now that more tools are available. This review provides an overview of recent advances in the molecular biology and regulation of the nucleoside and nucleobase transporters.
Cabrita
Miguel A
MA
Department of Biochemistry, Cross Cancer Institute, University of Alberta, Edmonton, Canada.
Baldwin
Stephen A
SA
Young
James D
JD
Cass
Carol E
CE
D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism; D000998:Antiviral Agents / Q000378:metabolism; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D005057:Eukaryotic Cells / Q000502:physiology*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008967:Molecular Biology; D033703:Nucleoside Transport Proteins / Q000502:physiology*; D009705:Nucleosides / Q000378:metabolism*; D011387:Prokaryotic Cells / Q000502:physiology*
D000970:Antineoplastic Agents; D000998:Antiviral Agents; D033703:Nucleoside Transport Proteins; D009705:Nucleosides