Activation of βC is required for BMP-2–mediated hPASMC motility. (A) Levels of active βC in lysates obtained from 10 ng/ml BMP-2–stimulated cells over 6 h were measured by Western immunoblotting (top) and quantified using densitometry (bottom) expressed as the ratio of the OD of βC relative to α-tubulin. (B) RhoA (top) and Rac1 (bottom) activation was measured in lysates from cells transfected with either scrambled or two independent βC siRNAs stimulated with BMP-2 over a period of 6 h using the approach described in Materials and methods. Densitometry values are shown relative to total RhoA and Rac1 in whole cell lysates, which were run in different gels. (C) Boyden chamber assays were performed as previously described to measure the impact of two independent βC versus scrambled (SC) siRNA on hPASMC motility. Bars represent means ± SEM from n = 3. *, P < 0.01; and ***, P < 0.0001 versus control (CON) in A and B were determined using one-way ANOVA with Dunnett’s. ***, P < 0.0001 versus time 0; and ^##, P < 0.001 versus scrambled siRNA in C were determined using one-way ANOVA with Bonferroni’s.