Fig. 9. S1P-induced HUVEC migration is inhibited by PP2. (A) Confluent monolayers of HUVECs were scraped with a 26G needle and the effect of 0.5 µM S1P or 10 nM thrombin on cell migration into the wounded area was observed in the presence or absence of 5 µM PP2 or 10 µM U0126. Two hours after agonist addition, cultures were fixed and the actin cytoskeleton was stained with phalloidin-FITC (bar, 40 µm). (B) Serum-starved HUVECs were treated with 0.5 µM S1P for the indicated times prior to analysis of Erk activation by western blotting using an anti-phospho Erk antibody (pErk1/2).