Figure 4

C. trachomatis -induced activation of PLCγ1, STAT5 and Akt is EGFR-dependent. (A) and (B) MEFs EGFR^+/+ were treated with either scrambled (control) or EGFR siRNA and then infected with C. trachomatis. Cells were lysed after 2.5 hpi and immunoblotted with antibodies against phosphorylated and total PLCγ1, STAT5 and Akt (A). Western blots from three independent experiments were quantified. (B). (C-E) HeLa and MEFs EGFR^+/+ were treated with Cetuximab (an anti-EGFR antibody that blocks the binding of EGF to EGFR thus blocking receptor activation) followed by C. trachomatis infection. At 2.5 hpi the lysates were immunoblotted with antibodies against phosphorylated and total EGFR, PLCγ1, STAT5 and Akt (C). Western blots from three independent experiments were quantified for both HeLa (D) and MEFs (E). C. trachomatis-induced phosphorylation of PLCγ1, STAT5 and Akt was completely or partially abrogated in cells that were either depleted of EGFR (A and B; P < 0.01) or treated with Cetuximab (C-E; P < 0.05). β-actin was used as loading control.