FIG 4.

IcmS dependency is regulated by sites within the C-terminal 50 amino acids. THP-l cells were infected for 48 h with wild-type C. burnetii or the icmS mutant producing CyaA fused to the indicated amino acids. Histograms depict the fold change in cytosolic [cAMP] for cells infected with C. burnetii producing N-terminal truncated forms of CBU0794 (IcmS dependent) (A) or CBU1525 (IcmS inhibited) (B) or C-terminal truncated forms of both proteins (C). The cutoff for positive secretion is indicated by a dotted line at 2.5-fold change [cAMP]. Error bars indicate the standard deviations from the means for two independent experiments conducted in duplicate.