TY - JOUR T1 - The Human Concentrative Nucleoside Transporter-3 C602R Variant Shows Impaired Sorting to Lipid Rafts and Altered Specificity for Nucleoside-Derived Drugs JF - Molecular Pharmacology JO - Mol Pharmacol SP - 157 LP - 165 DO - 10.1124/mol.110.063552 VL - 78 IS - 2 AU - Ekaitz Errasti-Murugarren AU - Miriam Molina-Arcas AU - F. Javier Casado AU - Marçal Pastor-Anglada Y1 - 2010/08/01 UR - http://molpharm.aspetjournals.org/content/78/2/157.abstract N2 - The human concentrative nucleoside transporter-3 C602R (hCNT3C602R), a recently identified human concentrative nucleoside transporter-3 (hCNT3) variant, has been shown to interact with natural nucleosides with apparent Km values similar to those of the wild-type transporter, although binding of one of the two sodium ions required for nucleoside translocation is impaired, resulting in decreased Vmax values (Mol Pharmacol 73:379–386, 2008). We have further analyzed the properties of this hCNT3 variant by determining its localization in plasma membrane lipid domains and its interaction with nucleoside-derived drugs used in anticancer and antiviral therapies. When expressed heterologously in HeLa cells, wild-type hCNT3 localized to both lipid raft and nonlipid raft domains. Treatment of cells with the cholesterol-depleting agent methyl-β-cyclodextrin resulted in a marked decrease in hCNT3-related transport activity that was associated with the loss of wild-type hCNT3 from lipid rafts. It is noteworthy that although exogenously expressed hCNT3C602R was present in nonlipid raft domains at a level similar to that of the wild-type transporter, the mutant transporter was present at much lower amounts in lipid rafts. A substrate profile analysis showed that interactions with a variety of nucleoside-derived drugs were altered in the hCNT3C602R variant and revealed that sugar hydroxyl residues are key structural determinants for substrate recognition by the hCNT3C602R variant. ER -