Challenge: G protein-coupled receptors (GPCRs) are the largest target class for approved drugs. Identification of new drug candidates has relied exclusively on high-throughput assays which track binding properties and are limited to a restricted number of signaling pathways. GPCRs are highly dynamic proteins that undergo numerous conformational changes upon receptor association with ligands and related protein partners. The use of such drug-induced conformational changes to identify new therapeutics has so far been overlooked due to the difficulty in adapting structural approaches to high-throughput screening.

Solution: This project focuses on generating in vitro cell assays based on fluorescent and bioluminescent resonance energy transfer (FlAsH or BRET) to analyze conformational dynamics of receptor activation in real-time upon ligand binding, engagement of G proteins and other effectors. Hence, the “FlAsHwalk” strategy allows for the development of new drugs by guiding the design of candidates based on structural features and conformational dynamics of target receptors, in the receptor’s natural biological context. These interactions between GPCRs and their partners can be measured in real-time allowing cell-based assays to be used in high throughput screening and high content screening modes.

Expected Achievements/Impact: Results of proof of concept studies showed that receptor reporters produced unique FlAsHwalk signatures or “heat maps” that are characteristic for specific types of interactions with molecules or protein partners. Importantly, the team demonstrated that FlAsHwalk maps can be correlated with various phenotypic measures of drug effects, including signaling pathways and cellular changes. The “FlAsHwalk” approach can be used to directly assess and stratify new candidate molecules and existing drugs without necessarily knowing their full signaling phenotypes, in any cell type and for any potential GPCR drug target. The team is using the platform to develop a pipeline of proprietary drugs. They are also discussing with a biotech to adapt the FlAsHwalk technology to stem cells.