888 www.sbsonline.org © 2008 Society for Biomolecular Sciences Demonstration of Improvements to the Bioluminescence Resonance Energy Transfer (BRET) Technology for the Monitoring of G Protein–Coupled Receptors in Live Cells

The bioluminescence resonance energy transfer (BRET) technique has become extremely popular for studying protein-protein interactions in living cells and real time. Of particular interest is the ability to monitor interactions between G protein–coupled receptors, such as the thyrotropin-releasing hormone receptor (TRHR), and proteins critical for regulating their function, such as β-arrestin. Using TRHR/β-arrestin interactions, we have demonstrated improvements to all 3 genera-tions of BRET (BRET1, BRET2, and eBRET) by using the novel forms of luciferase, Rluc2 and Rluc8, developed by the Gambhir laboratory. Furthermore, for the 1st time it was possible to use the BRET2 system to detect ligand-induced G protein–coupled receptor/β-arrestin interactions over prolonged periods (on the scale of hours rather than seconds) with a very stable signal. As demonstrated by our Z′-factor data, these luciferases increase the sensitivity of BRET to such an extent that they substantially increase the potential applicability of this technology for effective drug discovery high-throughput screening. (Journal of Biomolecular Screening 2008:888-898) Key words: bioluminescence resonance energy transfer (BRET), cell-based assays, G protein–coupled receptor, arrestin, luciferas