FIGURE 5.
Role of arrestin-3 SUMOylation on GPCR internalization. FLAG-β2AR (A) and FLAG-AT1aR (B) internalization was assessed in COS-1 cells co-transfected with HA-arrestin-3 WT, 4K/R, 2K/R, or empty vector (pcDNA) upon treatment with vehicle (0.01 mm ascorbic acid) and 10 μm isoproterenol for 30 min by ELISA. The data represent the averages from three independent experiments, and the error bars represent the standard error of the mean. The data were analyzed by a one-way analysis of variance followed by Bonferroni's post-hoc test. Wild-type arrestin-3, but not the SUMO-deficient mutants, was significantly different from pcDNA (p < 0.05). Shown in the insets are representative IBs to detect expression of HA-tagged arrestins.