IMPROVED SYSTEMS FOR SENSITIVE DETECTION OF G-PROTEIN COUPLED RECEPTOR AND ORPHAN RECEPTOR FUNCTION USING REPORTER ENZYME MUTANT COMPLEMENTATION
Methods of detecting G-protein coupled receptor (GPCR) signal activation by employing a GPCR fusion protein comprising an inactive form of an enzyme and an interacting protein partner fusion protein comprising a complementary inactive form of the enzyme contained in the GPCR fusion protein. When the GPCR fusion protein and the protein partner fusion protein bind to one another the two forms of the inactive enzyme associate and produce an active heterodimeric enzyme which is active, permitting detection of the interaction of the GPCR fusion protein with the interacting protein partner fusion protein by measuring the enzyme activity.