Fig. 4.

CB₁-stimulated FAK phosphorylation at tyrosines 397 and 576/577 involves activation of Src and inhibition of Protein Kinase A in N18TG2 cells. Cells were pretreated for 15 min with the Src inhibitor PP2 (2 μM) or Protein Kinase A activator Sp-cAMPS (10 μM) prior to treatment with 0.01 μM WIN55212-2 (WIN) for 1 or 2 min at 37°C. Immunoblot analysis was performed and data are reported as mean ± SEM of the % change over basal (A,C) pFAK tyrosine 576/577 levels and (B,D) pFAK tyrosine 397 levels (normalized to total FAK at each time point) from three separate experiments. WIN55212-2-stimulated values are expressed as 100%, and inhibitor-treated values are expressed as a percent of WIN55212-2-treated pFAK/FAK levels. * p < 0.001, # p < 0.05 indicates significantly different from WIN55212-2-stimulated at the same time point using Student's t-test.