p16^INK4a deficiency diminishes JAK2-STAT1 and NF-κB signaling and increases acetylation of STAT1 and IKKα,β. Total protein extracts of p16^+/+ and p16^−/− BMDM treated with 15 ng/mL IL-4 (A), 2.5 ng/mL IFNγ (B) and (E), and 100 ng/mL LPS (C) for the times indicated. Western blots were performed with the indicated Abs. (D) Total protein extracts from p16^+/+ and p16^−/− BMDM treated with 2.5 ng/mL IFNγ for 5 hours were then immunoprecipitated (IP) with an anti-Acetyl-Lys Ab and then immunoblotted with an anti-STAT1 Ab or with an anti-IKKα,β Ab, as indicated. Input corresponds to 5% of total protein extract used for immunoprecipitation.