Current Progress on Equilibrative Nucleoside Transporter Function and Inhibitor Design.

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Physiological nucleosides are vital for DNA, RNA, and ATP synthesis and act as signaling molecules.
• Nucleoside transporters, specifically SLC28 (CNTs) and SLC29 (ENTs), mediate the uptake of both physiological nucleosides and nucleoside-based drugs.
• The four human equilibrative nucleoside transporter (hENT) paralogs exhibit distinct tissue expression, subcellular localization, and substrate specificities.

Purpose of the Study:

• To provide an overview of structure-function relationships within the equilibrative nucleoside transporter (ENT) family.
• To highlight ligand binding and transport mechanisms, referencing a new hENT1 homology model.
• To discuss recent advancements in discovering paralog-selective small-molecule ENT inhibitors for therapeutic development.

Main Methods:

• Review of existing literature on ENT structure-function relationships.
• Analysis of ligand binding and transport data in the context of a new hENT1 homology model.
• Discussion of recent developments in small-molecule ENT inhibitor discovery, including natural product-inspired compounds.

Main Results:

• A generic residue numbering system for ENTs has been established to standardize the interpretation of mutational data.
• Recent progress has been made in identifying new paralog-selective small-molecule ENT inhibitors.
• Advances in heterologous production of functional ENTs are enabling deeper insights into their structure and function.

Conclusions:

• Understanding ENT structure-function is key to developing targeted therapies.
• The discovery of selective ENT inhibitors holds significant therapeutic potential for cancer and viral diseases.
• Continued research, aided by functional ENT production, will drive the rational design of highly selective inhibitors.