Figure 2.

Integrin-mediated translocation of Rac1 to the membrane involves the polybasic domain of Rac1. (A) HeLa cells expressing the indicated GFP-tagged Rac1 wild-type (wt) or mutant variants were incubated with FN-coated beads for 20 min (shown in the phase-contrast image; DIC). Cells were fixed and stained with appropriate antibodies to visualize endogenous PIPKI-α (Iα) and with Alexa Fluor 647–conjugated phalloidin to visualize actin. GFP fluorescence was recorded directly. Fluorescence intensity profiles showing the extent of GFP (green), PIPKI-α (red), and F-actin (blue) colocalization were determined along the lines drawn and are shown to the right. (B) HeLa cells were incubated with FN-coated beads for 20 min. Cells were fixed and immunostained for endogenous RhoGDI. Actin was visualized with Alexa Fluor 647–conjugated phalloidin. (right) Line scans of fluorescence intensity of RhoGDI (green) and F-actin (blue) signals are shown. Images are representative examples of three separate experiments. Bars, 10 µm.