Differential effects of PKCα and Rho inhibitors on Stx1B- and Stx2B-induced VWF secretion and PLD activation. HUVECs were preincubated with buffer or ROCK inhibitor Y27632 (100μM), Rho family GTPase inhibitor exoenzyme C3 (1 μg/mL), or PKCα inhibitor Gö6976 (2μM) before stimulation with Stx1B (A) or Stx2B (B) for 10 minutes. PLD activity was quantified as described in “Methods.” Graphs represent the average results of 3-5 independent experi-ments. HUVECs were treated with inhibitors before stimulation with Stx1B (C) or Stx2B (D). Cell-surface VWF under each condition was quantified as described in “Methods.” Values for each condition were normalized to the amount of VWF secreted by unstimulated cells. Data reflect the average results of 4 independent experiments. Comparisons with the reference condition are significantly different as indicated: *P < .05; **P < .01.