FIGURE 6.

Recruitment of β-arrestin 2 by CCR2 and CCR5 upon stimulation by J113863 or UCB35625. Real-time measurement of BRET signal in HEK293T cells expressing either β-arrestin2-RLuc8 and CCR2-Venus (A and B) or β-arrestin2-RLuc8 and CCR5-Venus (C and D) and stimulated with CCL2 (▴), CCL4 (■), UCB35625 (●), or J113863 (○). For kinetics, BRET signals were measured after the addition of 100 nm of chemokine or 100 μm J113863 or UCB35625. For dose-response curves, BRET was recorded 30 min after stimulation with various concentrations of ligands. Results are expressed as net BRET, corresponding to the difference in BRET signal between cells expressing arrestin plus receptor and cells expressing arrestin only. Data represent the mean ± S.E. of three independent experiments.