Sodium-dependent, pyrimidine- and purine-selective (  ). Involved in the homeostasis of endogenous nucleosides (, ). Exhibits the transport characteristics of the nucleoside transport system cib or N3 subtype (N3/cib) (with marked transport of both thymidine and inosine) . Employs a 2:1 sodium/nucleoside ratio . Transports uridine . Also able to transport gemcitabine, 3'-azido-3'-deoxythymidine (AZT), ribavirin and 3-deazauridine (, ).
Subcellular locations: Cell membrane
Subcellular locations: Endoplasmic reticulum membrane
Expressed in pancreas, bone marrow, trachea, mammary gland, liver, prostate, and regions of intestine, brain, lung, placenta, testis, kidney, and heart.