Wednesday, September 17, 2014

Measuring GPCR signaling with a fast kinetic BRET assay.

G-protein coupled receptors or GPCR's remain a very important subject of study due to their integral role in a variety of physiological processes. For example, the dopamine receptor is a GPCR that is a major target of drugs designed to assist in conditions such as Parkinsons disease. Therefore, continued efforts are being made to monitor the activity of GPCR's in order to identify new treatment options.

In a recent paper in the journal PLOS ONE the authors describe an approach based on bioluminescence resonance energy transfer or BRET to monitor dopamine receptor activation. As with other BRET approaches this assay monitors a protein-protein interaction which in this case is indicative of dopamine receptor activation. A binding peptide was linked to the recently engineered NanoLuc luciferase and a protein that binds to this peptide was linked to the Venus fluorophore. Treatment with agonist leads to association between the peptide and protein which brings NanoLuc into proximity of the Venus leading to a BRET signal.

"Dopamine Electron Map" by Jaelkoury - Rendered on Spartan.
Licensed under Creative Commons Attribution-Share Alike 3.0
via Wikimedia Commons
To achieve detection of the BRET signal the authors used a POLARstar Omega plate reader from BMG LABTECH to detect light emitted by Venus and NanoLuc. Furthermore, they were able to perform detection with a 50 millisecond resolution which enabled detailed analysis of activation kinetics in response to dopamine as well as deactivation kinetics.

For more information on the POLARstar Omega and other microplate readers from BMG LABTECH please visit:

Article citation: J.C. Octeau, et al. "G Protein Beta 5 Is Targeted to D2-Dopamine Receptor-Containing Biochemical Compartments and Blocks Dopamine-Dependent Receptor Internalization" PLoS One20149(8)