Figure 4
CiaD is required for activation of the MAP kinase signaling cascade. (A) The amount of IL-8 in supernatants is significantly increased 4 hr post infection in the C. jejuni wild-type strain when compared to the ciaD mutant. (B) Maximal activation of p38 and Erk 1/2 requires CiaD, as judged by immunoblots. Immunoblots were probed with phospho-specific antibodies to Erk 1/2 (Mr = 42 and 44 kDa), p38 (Mr = 38 kDa), and NF-κB p65 subunit phospho-S536 (Mr = 65 kDa). All blots were stripped and re-probed with an anti-tubulin (Mr = 52 kDa) antibody. (C) Maximal activation of p38 and Erk 1/2 requires CiaD. Densitometry was performed on the immunoblots shown in Panel B. The value obtained for cells only was subtracted from all other values. The asterisks indicate a significant difference in values compared to the controls, as judged by one-way ANOVA followed by post-hoc Tukey’s analysis (P < 0.05). Error bars represent ± SEM of N = 6 samples from 6 independent experiments.