FIGURE 2.

Membrane deformation of substrate-anchored endothelial cells under control conditions and after being exposed to latrunculin A. (Inset) The effect of latrunculin A on F-actin filaments visualized with rhodamine phalloidin. The bright spots in phalloidin staining were observed in most of the images suggesting that the treatment may result in collapse and condensation of actin fibers. The bar is 25 μm. (A) Progressive deformation of control cells compared to that of cells exposed to 2μM latrunculin A for 10 minutes. The edges of the cells have dimmer fluorescence than cell centers because in the cell center fluorescent signal comes not only from the plasma membrane but also from endocytosed vesicles. (B) Time course of membrane deformation where L is the aspirated length of the membrane projection and 2a is the inner diameter of the pipette. Cells were aspirated at −10 mm Hg (♦), −15 mm Hg (▪), and −20 mm Hg (▴). (C) Maximal membrane deformation as a function of applied pressure. Maximal deformation was determined by taking the values at which the aspiration length plateaued for each pressure. The maximal normalized length in latrunculin treated cells was significantly greater than control cells for all pressures (P < 0.05).