Fig. 3

A–F: The D427H mutation does not alter cytokine-induced nuclear translocation of STAT3. U3A cells were transfected with GFP- and SNAP-tagged STAT3 variants and stimulated with either 25 ng/ml of IL-6 or 50 ng/ml of IFNγ for the indicated times. A The fluorescence micrographs show the intracellular distribution of GFP/SNAP-tagged WT and mutant STAT3, as well as the localization of the corresponding Hoechst-stained nuclei in cells stimulated with IL-6 for 0, 20 and 30 min. Histograms demonstrating the unaltered kinetics of D427H-GFP (B) and D427H-SNAP (C) nuclear accumulation as compared to the WT upon stimulation with IL-6, as determined by the ratio of nuclear-to-total fluorescence intensity (n = 3 independent transfections). D The fluorescence micrographs show the intracellular distribution of GFP/SNAP-tagged WT and mutant STAT3, as well as the localization of the corresponding Hoechst-stained nuclei following IFNγ stimulation. Histograms demonstrating the unchanged kinetics of D427H-GFP (E) and D427H-SNAP (F) nuclear accumulation compared to the WT protein, as determined by the ratio of nuclear-to-total fluorescence intensity (n = 3 independent transfections). Means ± standard deviations from n = 20 cells with *p ≤ 0.05