Nucleoside transporter protein (NT)

Nucleoside transporter proteins are integral membrane proteins responsible for the selective uptake of nucleosides, nucleobases, and nucleoside-derived drugs into cells[2][5][8]. In humans, there are two main molecular families: equilibrative nucleoside transporters (ENTs, SLC29) and concentrative nucleoside transporters (CNTs, SLC28)[2][5]. ENTs operate via facilitated diffusion (passive transport, sodium-independent), while CNTs use sodium or proton gradients to drive active, unidirectional uptake[2][3][7]. Both types are critical for nucleic acid synthesis, salvage pathways, and cellular homeostasis of nucleosides, and also play major roles in the pharmacokinetics and efficacy of anticancer and antiviral drugs[5][8]. They are highly relevant as therapeutic targets and biomarkers, especially in cancers and viral infections where nucleoside analogues are used as drugs[3]. In addition, by regulating extracellular adenosine concentrations, nucleoside transporter proteins modulate cardiovascular, neurological, and immunological functions[5][8]. Dysfunction or altered expression of these transporters impacts disease susceptibility, drug efficacy, and toxicity profiles.

Other names

Nucleoside transporterEquilibrative nucleoside transporter (ENT, SLC29 family)Concentrative nucleoside transporter (CNT, SLC28 family)SLC28 and SLC29 transportersNTNucleoside carrier protein(For individual family members: hENT1, hENT2, hCNT1, etc.)

Facilitate or inhibit cellular uptake of nucleoside analogues (for chemotherapy and antiviral agents); Inhibition of ENT (e.g., by dipyridamole) elevates extracellular adenosine, mediating vasodilation and neuromodulation; Modulate efficacy of nucleoside-based drugs through transporter-dependent entry into cells; Alter adenosine signaling by regulating available adenosine levels