Figure 3.

RGS4 accelerates the deactivation of Gαi1 proteins following receptor activation. (A) HEK 293 cells were transfected with 200 ng of α2A‐adrenergic receptor, 200 ng of Venus‐Gβ1, 200 ng of Venus‐Gγ2, 25 ng of mas‐GRK3ct‐Luc, and 400 ng of Gαi1 and monitored for kinetic BRET as in Figure 1. Average whole traces of BRET signal over time are shown from cells expressing Gαi1 alone and 3, 10, 30, or 100 ng of HA‐RGS4 (n = 3). (B) Maximum ΔBRET observed from data presented in (A). (C) Deactivation curves normalized to Maximum BRET and fit using a single exponential decay function. (D) Deactivation rates (k _deactivation) determined from curves fit in (C). Error bars represent ± S.E. Statistical analysis was performed using a one‐way analysis of variance (ANOVA) with Tukey's post hoc test (*P < 0.05, **P < 0.01).