FAK activation influences caveolin-1 induction. (A) FAK and Src phosphorylation increases over time in culture. Blocking FAK phosphorylation with PF573228 (4 μM) culminates in reduced phospho-Src and N-Cadherin expression as well as attenuated caveolin-1 upregulation. E-Cadherin expression is unchanged. Caveolin-1 expression was densitometrically analyzed. A significant downregulation was observed at day 3 (p = 0.002) and day 4 (p = 0.011) (B) Blocking FAK (PF573228, 4 μM) leads to reduced AKT and ERK phosphorylation. Inhibition of Src kinases results in attenuated AKT and ERK phosphorylation. SU6656 (15 μM) additionally affects FAK phosphorylation, whereas PP2 (10 μM) does not. These data indicate that FAK signals via Src/ERK/AKT.