FIGURE 2.

AFM images of endothelial cells showing VEGF induced cytoskeletal reorganization, (A) before adding VEGF and (B) 2 h after adding VEGF (25 nM). Cytoskeletal reorganization as well as a change in the elasticity is observed. Cell softness is reflected in a loss of fine ultrastructural details. (C–D) Immunofluorescence labeling of Flk-1 receptors in the plasma membrane. Endothelial cells show immunolabeling with a polyclonal anti-Flk-1 antibody followed by cy-3 conjugated secondary antibody. D shows a zoomed image of a portion of C. Receptors are distributed throughout the cell surface with a higher density along the cell periphery. (E) Endothelial cells show no immunolabeling with a nonspecific antibody followed by cy-3 conjugated secondary antibody.