FIGURE 11.

ICL3-9 promotes G_s coupling to the β₂AR differently from a β-agonist. A, schematic of G_s engagement analysis by BRET. Upon β-agonist stimulation, RLucII-Gα_s is engaged by the β₂AR-GFP10 in a manner that causes a decrease in BRET signal. B, HEK 293 cells co-transfected with RLucII-Gα_s and β₂AR-GFP10 were preincubated with coelenterazine 400a for 2 min and stimulated with 10 μm pepducin or 10 μm isoproterenol. Changes in BRET were monitored over the indicated time points. 0.05% DMSO was included in non-pepducin-stimulated trials. The data are represented by the mean of three independent experiments ± S.D. In contrast to isoproterenol, ICL3-9 promoted an increase in BRET indicating a different mode of engagement of G_s by the pepducin-activated receptor that results in a different conformation of the complex.