Last December we published an Article by Simon Davis and colleagues challenging the conventional methodology being used in BRET studies that detect dimerization of G protein coupled receptors. The conclusions were contested in a Correspondence by Michel Bouvier and colleagues. In a new Correspondence, a former member of the Bouvier lab further argues against the results and conclusions of the Davis study with experimental results using the ‘Type 2’ BRET assay of Davis and colleagues.
It is difficult to draw firm conclusions regarding the accuracy of the disparate results. Both sides have reasonable arguments. The use of known dimerizing and non-dimerizing controls to validate their method in the original report by Davis and colleagues argues for the accuracy of their method in general. Unfortunately, the ‘Type 1′ assay which is the basis of their conclusions is difficult to set up properly compared to conventional or ‘Type 2′ BRET assays.
Regardless of whether or not GPCRs dimerize in vivo, it is clear from the arguments being made that great care must be taken to ensure that BRET experiments are set up properly and expression levels of the putative interacting proteins are carefully validated.
What are your experiences using BRET to detect receptor dimerization? Is there a simple explanation for these disparate results that is being overlooked? Are further developments of the assay needed to easily ensure that receptor expression is at endogenous levels while still providing a strong signal? Share your thoughts.