Uniporter that mediates the facilitative transport of nucleoside across lysosomal and mitochondrial membranes (PubMed:15701636, PubMed:19164483, PubMed:20595384, PubMed:28729424). Functions as a non-electrogenic Na(+)-independent transporter (PubMed:15701636, PubMed:19164483, PubMed:28729424). Substrate transport is pH-dependent and enhanced under acidic condition, probably reflecting the location of the transporter in acidic intracellular compartments (PubMed:15701636, PubMed:19164483, PubMed:28729424). Proton is not a cotransporting ion but most likely change the ionization state of the transporter which dictates transport-permissible/impermissible conformation for nucleoside translocation (PubMed:28729424). May direct the nucleoside transport from lysosomes to cytosol or cytosol to mitochondria to facilitate the fundamental function of salvage synthesis of nucleic acids (PubMed:28729424). Involved in the transport of nucleosides (adenosine, guanosine, uridine, thymidine, cytidine and inosine) and deoxynucleosides (deoxyadenosine, deoxycytidine) (PubMed:15701636, PubMed:19164483, PubMed:20595384, PubMed:28729424). Also mediates transport of purine nucleobases (adenine, guanine) and pyrimidine nucleobases (uracil) (PubMed:15701636, PubMed:19164483). Also able to transport monoamine neurotransmitters dopamine, serotonin, noradrenaline and tyramine (PubMed:19164483). Capable of transporting ATP (PubMed:19164483). Mediates nucleoside export from lysosomes in macrophages, which regulates macrophage functions and numbers (By similarity).
