Syx and RhoA colocalized in response to VEGF. A, there was little colocalization of Syx and RhoA in quiescent ECs. B, Syx and RhoA colocalized on endocytic vesicles within 2 min of stimulation by 20 ng/ml VEGF-A164. C, Syx and RhoA polarized in the direction of the VEGF-A164 gradient (0–20 ng/m) and colocalized on endocytic vesicles. D, quantification of the extent and angular distribution of Syx and RhoA colocalization in ECs subjected to a VEGF-A164 gradient (0–20 ng/m). The gradient direction is 0 degrees (mean ± S.D., n = 10; p < 0.0001). Bars, 10 μm.