Fig. 3. S1P induces co-localization of cortactin and actin in lamellipodia. Serum-starved HUVECs were treated, or not (control), with S1P (0.5 µM) or thrombin (10 nM) for 2 minutes. After fixation and permeabilization, cells were stained with anti-cortactin antibody (left panels) and phalloidin-FITC (middle panels) and analyzed by confocal microscopy. Merged image pairs (right) highlight regions of co-localization (orange).