Fig. 3

Acetylated STAT1 inhibited STAT3 nuclear translocation. Pseudoacetylated STAT1 mutant (K410/413Q) decreased total STAT3 in the nuclear fraction (b) but had no effect on the total STAT3 level in the whole extracts of HEK293 cells (a) detected by Western blotting and quantitative analysis (c). c One-way analysis of variance (ANOVA) followed by the Bonferroni’s post hoc test, nuclear STAT3 level [K410/413Q] p = 0.027, n = 4. The unacetylated (K410R, K413R, K410/413R) STAT1 mutant did not change STAT3 levels in total extracts (d) or the nuclear fraction (e), as determined by Western blotting and quantitative analysis (f). K410/K413R-STAT1 (K410/413R) restored P301L-induced reduction of decreased STAT3 in the nuclear fraction, as determined by Western blotting (g, h) and quantitative analysis (i). i Two-tailed Student’s t test, nuclear STAT3 level p = 0.044, n = 4. j K410/K413Q-STAT1 decreased the luciferase activity of STAT3. One-way analysis of variance (ANOVA) followed by the Bonferroni’s post hoc test, STAT3 luciferase activity [K410Q] p = 0.002; [K410/413Q] p < 0.001, n = 4. k Unacetylated (K410R, K413R, K410/413R) STAT1 mutant did not affect the luciferase activity of STAT3. l STAT1KR (K410/413R) rescued the decreased luciferase activity of STAT3 induced by P301L-hTau. Two-tailed Student’s t test, p = 0.007, n = 4. Data were presented as mean ± SEM