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. 2013 Mar 20;8(3):e60215. doi: 10.1371/journal.pone.0060215

Figure 1. Toxoplasma induces STAT1 phosphorylation and nuclear translocation in BMDC.

Figure 1

(A) BMDC were left in medium alone (Med), infected with type I (RH), II (PTG) or III (M774.1) strains of Toxoplasma (3∶1 ratio of parasites to cells), or treated with murine IFNγ (100 ng/ml), prior to fractionation into cytoplasmic (C) and nuclear (N) extracts at the time points indicated. Samples were subjected to immunoblot analysis for phospho-Tyr701-STAT1 (pY-STAT1) and phospho-Ser-STAT1 (pS-STAT1). PARP and Rab5a served as loading controls for nuclear and cytoplasmic fractions, respectively. (B) Cells were infected with live parasites of the three strains as in (A) or exposed to heat-inactivated (HI) tachyzoites for six hours. Cytoplasmic and nuclear fractions were collected and immunoblot analyis was performed as in (A). (C) RH parasites were pre-treated for 10 min on ice with 1 μM cytochalasin D (CytD) prior to infection in the continued presence of the drug. Cells treated with the solvent DMSO alone served as controls. Cells were fractionated after six hours and subjected to immunoblot analysis for pY-STAT1. (D and E) BMDC were treated with IFNγ or infected with RH in comparison with either the cps1-1 replication-deficient strain (D) or the ΔROP16 strain (E). Samples were fractionated after 6 and 20 hours and subjected to immunoblot analysis for pY-STAT1. All experiments were repeated at least three times with similar results.