Novel β-arrestin Assays that Advance GPCR Screening

PathHunter™ β-Arrestin Assays are homogeneous, cell-based GPCR screening assays. They directly measure GPCR activation through ß-arrestin interaction—without a second messenger, imaging, or reporter gene. In addition, using the new PathHunter Flash Detection Kit, results can be obtained in as few as 30 seconds after adding chemiluminescent substrate. Select from DiscoveRx’s rapidly expanding portfolio of over 90 β-Arrestin biosensor cell products for a product demonstration, or develop specific assays of interest using custom services.

Simple and Fast
In PathHunter β-Arrestin assays, ligand binding is measured using ß-arrestin recruitment by an expressed GPCR following activation. The GPCR and ß-arrestin are each fused to a fragment of ß-galactosidase (ProLink™ and EA), so that the protein-protein interaction permits ß-gal complementation. The resulting enzyme activity is easily detected in a microplate with a standard luminometer. The PathHunter assays’ single-addition, no-wash format, short incubation, and large assay windows make them ideal for high-throughput screening.

Direct
Unlike calcium, cAMP or reporter gene assays, PathHunter β-Arrestin assays measure the primary GPCR activation event, offering a novel, more direct means to interrogate GPCR biology. The direct measurement reduces off-target effects because signal is generated quickly rather than after the long incubation needed in reporter gene assays. Furthermore, signal is generated only from the expressed GPCR rather than endogenous GPCRs, resulting in exceptional selectivity that promises improved hit identification and validation.

Universal
PathHunter β-Arrestin assays are universal for Gi-, Gs-, and Gq-coupled receptors, making them ideal for de-orphanizing GPCRs. Short incubation time and independence from the coupling mechanism also makes these assays suitable for profiling and secondary screening.