Figure 6.

Function of actin cytoskeleton in the force-induced growth of focal contacts. To probe the role of actin cytoskeleton integrity, SV-80 cells were pretreated with 5 μM latrunculin A (Lat A) (A–B′); to block actomyosin-driven contractility, the cells were pretreated with 30 mM BDM (C–D′) or cotransfected with nonmuscle caldesmon (E–F′). Positions of the pipette tips, immediately after shift, are indicated by blue drawings. B′, D′ and F′ represent enlarged parts of B, D, and F, respectively. Images labeled before and after were taken 1–8 min before and 3–7 min after the pipette shift, respectively. Bars: (B, D, and F) 20 μm; (B′, D′, F′) 5 μm. Note that latrunculin A prevented formation of focal adhesions, whereas neither BDM nor caldesmon transfection interfered with this process.