Importance of FAK, EGFR, PDGFR and PI3-kinase activities for C. jejuni -induced activation of Cdc42 and bacterial invasion. (A) INT-407 monolayers were pre-incubated for 30 min with the indicated pharmacological inhibitors and infected with C. jejuni for 6 hours. Intracellular C. jejuni were quantified by gentamicin protection assays. The presence of active Cdc42-GTP was quantified by CRIB-GST pulldowns. One hundred % of activity corresponds to the highest amount of detected Cdc42-GTP level (lane 2). (B) Effect of overexpression of dominant-negative forms of PDGFR and EGFR on C. jejuni uptake. 48 hours post transfection INT-407 cells were infected with C. jejuni for 6 hours. Intracellular bacteria were quantified by gentamicin protection assays. Expression of the individual constructs was verified by Western blotting. GAPDH expression levels were determined as control. (*) P ≤ 0.05 and (**) P ≤ 0.005 were considered as statistically significant.