Fig. 5. MEKK1 localizes to focal adhesions. MEKK1–/– fibroblasts were transfected with EGFP–MEKK1, incubated in serum-free media for 12 h, then processed as described in Materials and methods and subjected to immunofluorescence analysis. (A) An MEKK1–/– MEF transfected with EGFP–MEKK1 and treated with anti-FAK antibodies (FAK displayed as red fluorescence). Bar = 10 µm. (B) Displayed are two representative examples of co-localization of EGFP–MEKK1 with endogenous FAK (purple) and actin (red). Bar = 1 µm.