Ang-1-dependent modulation of Rac1 and RhoA in ECs carrying N17Rac1 or N19RhoA, and LY294002 effect on activation in ECs. (A) Rho GTPase activities were evaluated in chemokinesis assay by using cells carrying N17Rac1, N19RhoA, or vector. (B) Starved, subconfluent ECs were preincubated (5 minutes) with or without LY294002 (25 μM) and then stimulated for 2 minutes with Ang-1 (50 ng/mL). PI 3-kinase was measured on antiphosphotyrosine mAb immunopreciptates (the level of PI(3,4,5)P in unstimulated cells was 26.2 ± 1.2 pmol, n = 3). (C) ECs were preincubated with LY294002 as detailed in panel B and then stimulated for the indicated times with Ang-1 (20 ng/mL) in chemokinesis assay. Densitometric analysis was evaluated as in Figure 4 (mean ± SD of 5 experiments; ^*P < .05 versus unstimulated cells by Student t test). (D) EC chemokinesis induced by Ang-1 in the presence or absence of LY294002 (25 μM). Mean ± SD of 3 experiments.