Fig. 4. Aberrant lamellipodia formation in cells treated with FAK siRNAs. Cells treated with either luciferase siRNA (A) or FAK siRNA (B) were allowed to spread on fibronectin and analyzed by time-lapse microscopy. Arrows in A indicate ruffling edge of the control cells; arrowheads in B indicate the formation of a projection in the FAK knockdown cells. (C) FAK knockdown cells were allowed to spread on fibronectin for 1 hour, then fixed and stained for paxillin. The white outline in the enlarged inset represents the plasma membrane.