Mediates both influx and efflux of nucleosides across the membrane (equilibrative transporter). It is sensitive (ES) to low concentrations of the inhibitor nitrobenzylmercaptopurine riboside (NBMPR) and is sodium-independent. It has a higher affinity for adenosine. Resistant to dipyridamole and dilazep inhibition (anticancer chemotherapeutics drugs). Identified in a complex with STOM. Predominantly localized in the basolateral membrane in polarized MDCK cells. Highly expressed in heart, spleen, lung, liver and testis. Lower level of expression in brain and kidney. Belongs to the SLC29A/ENT transporter (TC 2.A.57) family.