A549 cells were transfected with mock or anti-PP1α siRNA for 48 h, incubated in serum-free medium for 16-18 h, treated with vehicle or cortisol (10 nM and 50 nM cortisol) for 1 h, followed by cell lysis and Western blot analysis. A representative Western blot image (A) and densitometry values (B) are presented. Levels of phosphorylated Ser211 from three independent experiments were normalized to total GR levels and are depicted as values normalized to mock siRNA control (mean ± SD, ***P < 0.001, **P < 0.01, ns not significant).