Fig. 6. G3EGF expression increased and maintained FAK phosphorylation. Cells were cultured in DMEM containing 10% FBS for 24 hours followed by serum withdrawal and incubation in serum-free DMEM for different times. The cell lysate was prepared and immunoprecipitated with anti-FAK antibody, followed by western blotting probed with anti-phosphotyrosine antibody. U87 cells expressing G3EGF retained a prolonged FAK phosphorylation (p-FAK) compared with the vector-transfected cells. The same blot was also probed with anti-FAK antibody to assess equal protein loading. Additionally, the cell lysate was analysed on a western blot probed with anti-ß₁-integrin antibody. These experiments were repeated three times.