CODA-RET Assay

Cells were harvested, washed twice, and resuspended in PBS. Approximately 200 000 cells per well were distributed in 96-well plates and stimulated by indicated drugs dissolved in prewarmed PBS for 5 min at 37 °C. A concentration of 5 µM coelenterazine H (the substrate for luciferase) was added to each well (Dalton Pharma Services). Two minutes after the addition of coelenterazine H, the fluorescence and luminescence was quantified (Pherastar, BMG Labtech) and the BRET signal was determined by calculating the ratio of the emission of mVenus (510–540 nm) over the emission of Rluc8 (485 nm).