Nucleoside transport protein

Nucleoside transport proteins are integral membrane transporters responsible for mediating the movement of natural nucleosides and analog drugs across cellular membranes. In humans, two major families exist: concentrative nucleoside transporters (CNTs; SLC28A1, SLC28A2, SLC28A3) that use sodium or proton gradients for active uptake, and equilibrative nucleoside transporters (ENTs; SLC29A1, SLC29A2, SLC29A3, SLC29A4) that enable passive facilitated diffusion. These proteins are broadly expressed, with tissue-specific patterns, and play critical roles in nucleotide salvage pathways and in determining the effectiveness of nucleoside analog-based therapies for cancers and infectious diseases. Differences in substrate specificity, localization, and regulation between CNT and ENT subtypes influence their biological and pharmacological importance. Because of their central role in drug uptake and resistance, nucleoside transport proteins are important targets in drug development and in precision medicine approaches.

Other names

Concentrative nucleoside transporter (CNT)Equilibrative nucleoside transporter (ENT)SLC28 family (CNT1, CNT2, CNT3)SLC29 family (ENT1, ENT2, ENT3, ENT4)

Facilitate cellular uptake of therapeutic nucleoside analogs, enabling their phosphorylation and incorporation into DNA/RNA, leading to cytotoxic or antiviral effects. Specific inhibitors block nucleoside entry, modulating drug sensitivity or resistance.