Figure 5.

Protein kinase A is differentially activated during C. burnetii infection. Equal amounts of total lysate protein from THP-1 cells infected for the indicated times were analyzed by immunoblotting for PKA substrates phosphorylated at distinct serine or threonine residues, indicative of overall kinase activity. Molecular weight is given on the left of the blot. Asterisks represent proteins with increased phosphorylation levels at 24–96 hpi and circles denote proteins with decreased phosphorylation levels after 48 hpi. At least seven PKA substrates showed altered phosphorylation levels during infection, with increased phosphorylation of three proteins sustained through 96 hpi. C = uninfected cells.