Figure 1

EGFR is activated by C. trachomatis infection. (A) MEFs EGFR^+/+ and MEFs EGFR ^-/- cells were infected with C. trachomatis (Ct). Note the small chlamydial inclusions (in apple green) formed in the MEFs EGFR^-/- cells in comparison to the inclusions formed in MEFs EGFR^+/+ cells. Red color is the counterstaining of the host cell. (B)-(F) Phosphorylation of EGFR in C. trachomatis-infected cells. Monolayers of MEFs EGFR^+/+ (B) and HeLa (D) with and without chlamydial infection were lysed at different hpi as indicated and immunoblotted with antibodies against pY1173-EGFR and EGFR antibodies. The immunoblots from three independent experiments were quantified for both MEFs (C) and HeLa cells (E) after normalization with β-actin used as loading control. A significant increase (P < 0.05) in phosphorylation of EGFR in MEFs EGFR^+/+ (C) and HeLa cells (E) was observed at 2.5 hpi. (F) HeLa cells with and without chlamydial infection were lysed at 2.5 hpi. Two biological replicates were subjected to immunoblotting for pPDGFRβ (Y751) and β-actin as loading control. An increase in PDGFRβ phosphorylation was observed in C. trachomatis-infected cells compared with non-infected cells. (G) MEFs EGFR^+/+ were infected with C. trachomatis for 2.5 h or 5 h. Western blotting was performed for comparing EGFR phosphorylation by C. trachomatis at various tyrosine residues. C. trachomatis induced phosphorylation was observed at all sites analyzed with the exception of Y1148 site.