Fig. 2.

Progesterone and 17OHP binding induced conformational changes within GPR126 extracellular domains. (A) Schematic representation of the FlAsH-BRET assay design. NanoLuc (Nluc) was inserted at the N terminus of GPR126-β, and the FlAsH motif (CCPGCC) was incorporated in the designated positions at the ECLs of the receptor. (B) The maximal response of GPR126 FlAsH-BRET sensor S4 (annotated as WT) and the sensor-based CCPGCC mutants upon progesterone stimulation. Data are derived from the dose–response curves in SI Appendix, Fig. S4E, normalized to the maximal response of sensor S4. Values are the mean ± SEM from three independent experiments performed in triplicate. Data information: (B) ***P < 0.001; ND, not detectable; FlAsH-BRET sensors stimulated with progesterone were compared with those stimulated with control vehicle.