Fig. 2

Tyrosine-phosphorylated STAT1-E169A shows prolonged nuclear accumulation. HeLa cells expressing fusion proteins of STAT1-WT (A) or the H158A (B) and E169A (C) mutants were either left unstimulated or stimulated with 50 ng/ml IFNγ for 45 min, this being followed by incubation with staurosporine (1 µM) for the indicated times (scale bar corresponds to 50 µm). D Quantification of the results from Fig. 2A–C. STAT1-GFP fluorescence intensity data from n = 20 cells are shown as the ratio of nuclear-to-total STAT1. Asterisks indicate significant differences between the WT protein and the respective mutant