Figure 4.

Identification of defects in FAK phosphorylation. A) CE cells were transfected with the RCAS empty vector (mock) or RCAS encoding wild type FAK or FAK mutants. Subconfluent cells growing in culture were lysed and immunoblotted with the indicated phospho-specific antibodies. In parallel lysates were blotted for FAK expression as a loading control. B) Phosphorylation of FAK variants was examined in cells growing in culture (cul)(lanes 1, 4, 7, 10, 13), after incubation in suspension for 30 minutes (sus)(lanes 2, 5, 8, 11, 14), and after plating on fibronectin for 45 minutes (FN)(lanes 3, 6, 9, 12, 15). Twenty-five μg of lysate was analyzed by immunoblotting using phospho-specific antibodies. Lysates were also blotted for FAK as a loading control.