FIGURE 7.

ARRDC3 modulates β₂AR-dependent Gα_s protein-mediated signal transduction on endosomes. A, forskolin-normalized β₂AR-mediated cAMP response in cells with or without ARRDC3 overexpression. More than six independent experiments were performed. Representative experimental data are shown. B, forskolin-normalized β₂AR-mediated cAMP response in the absence or presence of 30 μm Dyngo-4a in cells with or without ARRDC3 expression. Four independent experiments were performed. Representative experimental data are shown. C, average of 10 consecutive maximum values of each condition in B. The graph represents the mean ± S.E. from four independent experiments. Unpaired t test. D, calculated by using numerical values from C. % of inhibition = (1 − (maximum value of control or ARRDC3 + Dyngo/maximum value of control or ARRDC3)) × 100. The graph represents the mean ± S.E. from the four independent experiments in C. Unpaired t test. E, representative confocal live cell images and co-localization analysis of HEK293 cells overexpressing pEGFP-ARRDC3 and Nb37-mApple. Cells were stimulated with 10 μm ISO for 20 min. n = 11. F, fluorescent intensity of Nb37-mApple on β₂AR-occupied early endosomes in the presence or absence of pEGFP-ARRDC3. The graph represents the mean ± S.E. from >50 endosomes for each condition. Unpaired t test.