Fig. 2. Polarization of caveolin-1 in response to fluid shear stress. Primary endothelial cells were either cultured on coverslips (unstressed) or exposed to a fluid shear stress at a force of 20 dynes/cm² (stressed) in a parallel-plate flow chamber for 24 hours as described. Cells were then processed for colocalization of the indicated protein by indirect immunofluorescence. White arrows indicate regions in stressed cells that were rich in caveolin-1 staining. These arrows also point in the direction of fluid flow. The yellow asterisk marks a cell extension that is rich in caveolin-1. Bar, 20 µm.