GloSensor assay for discovery of GPCR-selective ligands.

G protein-coupled receptors (GPCRs) are modulators of almost every physiological process, and therefore, are most favorite therapeutic target for wide spectrum of diseases. Ideally, high-throughput functional assays should be implemented that allow the screening of large compound libraries in cost-effective manner to identify agonist, antagonist, and allosteric modulators in the same assay. Taking advantage of the increased understanding of the GPCR structure and signaling, several commercially available functional assays based on fluorescence or chemiluminescence detection are being used in both academia and industry. In this chapter, we provide step-by-step method and guidelines to perform cAMP measurement using GloSensor assay. Finally, we have also discussed the analysis and interpretation of results obtained using this assay by providing several examples of Gs- and Gi-coupled GPCRs.