Unlocking GPCR-ligand interactions: Measuring binding affinities with thermal shift assay

Area of Science:

• Biochemistry
• Pharmacology
• Structural Biology

Background:

• G protein-coupled receptors (GPCRs) are a large superfamily of transmembrane proteins, crucial for drug discovery.
• Current methods for measuring GPCR ligand binding are complex and expensive.
• Understanding receptor-ligand interactions is vital for developing new therapeutics.

Purpose of the Study:

• To introduce and validate the thermal shift assay (TSA) as a cost-effective and user-friendly method for determining GPCR ligand binding affinities.
• To assess the reproducibility and accuracy of the TSA method for GPCR research.

Main Methods:

• Application of the thermal shift assay (TSA) to measure ligand binding to the human A2A adenosine receptor.
• Utilized three mathematical models for TSA data approximation and analysis.
• Validated the method using antagonists for the cysteinyl leukotriene GPCR (CysLT1R).

Main Results:

• Determined binding constants for four orthosteric ligands and allosteric sodium for the human A2A adenosine receptor.
• The TSA method demonstrated high reproducibility and agreement with existing literature data.
• Successful validation using CysLT1R antagonists confirmed the assay's applicability.

Conclusions:

• The thermal shift assay (TSA) is a suitable and reliable method for investigating ligand interactions with GPCRs.
• This approach offers a cost-effective alternative for drug discovery and pharmacological research.
• The TSA method can be applied to various types of GPCR ligands, enhancing therapeutic development.