Fig. 2. FAK siRNA knockdown results in abnormal cell spreading on fibronectin. REF52 cells were treated with either luciferase siRNA (A-C, G-I) or FAK siRNA (D-F, J-L). The cells were plated on fibronectin for the indicated times either in the absence (A-F) or presence (G-L) of 10% serum and stained for actin (green) and paxillin (red). Arrows in C and I indicate the smooth membrane of the control cells; arrowheads in L indicate the projections in the knockdown cells.