Human umbilical vein endothelial cells (HUVECS) labeled for focal adhesions (green) and F-actin (red). HUVECs were plated on polyacrilamide gels (1.5 Kpa) coated with 1.0 mg/ml fibronectin. After 24 hrs cells were fixed in 3% paraformaldehyde and stained with mouse antibody to Phosphotyrosine (4G10) monoclonal antibody detected with goat anti-mouse Alexa 565 and Alexa 488 phalloidin to stain for F-actin. Image was collected on a Nikon Eclipse with a cooled charge coupled device (CCD; Orca II; Hamamatsu Photonics) using a 60x 1.4 NA Plan Apo PH objective lens (Nikon). The exposure time was 320 msec each channel. A xenon arc lamp was used with a Semrock DA/FI/TR/Cy5-4x4M-B Sedat filter set.