FIGURE 9.

NFκB signaling is reduced in βarr2^−/− SMCs. A, SMCs of the indicated genotype were transfected with siRNA targeting no mRNA (Control) or USP20 mRNA. Cells were stimulated with 100 ng/ml LPS at 37 °C for the indicated times. Lysates were resolved by SDS-PAGE on BisTris gels (10% polyacrylamide) and immunoblotted (IB) for the indicated proteins. Arrowheads indicate the electrophoretic mobility for USP20 (second panel) and βarr2 (fourth panel). B, band intensities for IκBα were normalized to corresponding β-actin band intensities. These ratios were normalized to those obtained from unstimulated WT SMCs transfected with control siRNA to obtain percent of control, plotted as mean ± S.E. from a total of nine independent siRNA transfections in three independent pairs of WT and βarr2^−/− SMC lines. From two-way analysis of variance with Tukey's multiple comparison test, we found p < 0.05 for the following comparisons, designated by SMC genotype/(siRNA transfected): *, compared with WT/(control); ‡, compared with βarr2^−/−/(control); and †, compared with βarr2^−/−/(USP20).