Recruitment of Dvl by BMP-2 requires Smads and is independent of BMPRII functional status. (A) Active RhoA and Rac1 pull-down experiments on hPAEC nucleofected with either vector or dominant-negative (Δ) Smad1 construct and incubated with 10 ng/ml BMP-2 were analyzed as described in Fig. 6. **, P < 0.001 (vs. control [CON]). (B) Microcarrier bead assay using hPAECs nucleofected with vector (V) or ΔSmad1 was performed as in Fig. 6 D. ***, P < 0.0001 (vs. control); ##, P < 0.001 (vs. vector only stimulated with BMP-2). (C) Western immunoblots of BMP-2–stimulated hPAECs transfected with BMPRII siRNA or nontargeting control siRNA. Blots were probed for phosphorylated and total Smad1 and -3. **, P < 0.001 and ***, P < 0.0001 (vs. control). (D) Western immunoblots of hPAECs transfected with siRNA for both BMPRII and ActRIIa followed by stimulation with 10 ng/ml BMP-2 for 1 h. Blots were probed for phosphorylated and total Smad1 and -3. **, P < 0.001 and ***, P < 0.0001 (vs. control). (E) Microcarrier bead assay using hPAECs nucleofected with BMPRII siRNA along with vector or dominant-negative Smad3 (ΔSmad3). **, P < 0.001 (BMP-2–stimulated vector or ΔSmad3 vs. respective unstimulated control RNAi); +++, P < 0.0001 (BMP-2–stimulated vs. unstimulated BMPRII RNAi vector or ΔSmad3); ###, P < 0.0001 (vector vs. ΔSmad3). Error bars denote mean ± SEM for three different experiments with triplicate assessments.