Conformationally selective RNA aptamers allosterically modulate the β2-adrenoceptor.

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• G-protein-coupled receptors (GPCRs) are crucial drug targets, mediating cellular responses through various signaling pathways.
• Ligands stabilize distinct GPCR conformations, enabling biased agonism but posing challenges for structural studies.
• There is a need for novel allosteric modulators to probe GPCR conformational dynamics.

Purpose of the Study:

• To identify and characterize novel RNA aptamers as allosteric modulators of GPCRs.
• To investigate the ability of RNA aptamers to stabilize distinct GPCR conformations.
• To expand the toolkit for studying GPCR structure and function.

Main Methods:

• High-throughput RNA library screening coupled with next-generation sequencing and bioinformatics.
• Biochemical, pharmacological, and biophysical assays to characterize aptamer-GPCR interactions.
• Focus on the prototypical beta-2 adrenoceptor (β2AR) as a model system.

Main Results:

• Identification of high-affinity (nanomolar) RNA aptamers binding to the β2AR.
• Demonstration of allosteric stabilization of active, inactive, and ligand-specific β2AR conformations by aptamers.
• Validation of RNA aptamers as functional allosteric GPCR modulators.

Conclusions:

• RNA aptamers represent a new class of allosteric GPCR modulators.
• These aptamers provide valuable tools for dissecting GPCR conformational landscapes.
• The discovery broadens ligand diversity for GPCR structural biology and drug discovery.