Skip to main content
. 2003 Feb 11;100(4):1740–1744. doi: 10.1073/pnas.262789099

Figure 4.

Figure 4

Effect of siRNA-inhibited expression of β-arrestin on ERK activation in response to AT1A-R stimulation. HEK293 cells transiently expressing AT1A-R (≈300 fmol per mg of protein) by cotransfection with either control RNA (CTL) or the β-arrestin 2 siRNA were serum-starved for 1–2 h and stimulated with the indicated concentrations of AngII for 5 min at 37°C. Phosphorylation of ERK in whole-cell lysates, normalized to equal amounts of proteins in each sample, was detected by immunoblotting with an antiphospho-ERK 1/2 antibody as described. Equal loading of total ERK proteins were also confirmed by immunoblotting with an anti-ERK 1/2 antibody (data not shown). Each data point is expressed as percent of the maximal phosphorylation of ERK in response to 10−6 M AngII in control cells and represents the mean ± SE from seven independent experiments. Dose–response curves and EC50s between control RNA- and β-arrestin 2 siRNA-treated samples were obtained and analyzed by a two-way ANOVA to determine statistical significance for shift of the curve (P < 0.001) by using PRISM software. A representative immunoblot is shown (Upper).