Effect of RhoA and RhoB on myosin light chain and paxillin phosphorylation. (A) Pull-down assays of RhoA, RhoB, and RhoC during acute contraction induced with thrombin in HUVECs pretreated with TNF for 8 h. Graphs show active Rho normalized to total Rho levels from three different experiments. (B) TNF-pretreated, siRNA-transfected HUVECs were stimulated with thrombin for the indicated times and immunoblotted for the indicated proteins. (C and D) Quantification of phosphorylation of the indicated proteins from at least three experiments. **, P < 0.005.