Bcl-3 promotes Wnt signaling by regulating the K49 acetylation of β-catenin. a, b Immunoblot analyses of Bcl-3, Ac-K49-β-catenin, and β-catenin in control and Bcl-3-silenced HCT116 cells a and SW620 cells b. c Immunoblot analyses of Bcl-3, Ac-K49-β-catenin, and β-catenin in control and Bcl-3-silenced HCT116 cells treated with Wnt3a for 4 h (100 ng/ml). d, e Immunoblot analyses of Bcl-3, Ac-K49-β-catenin, and β-catenin in control, and Bcl-3-silenced HCT116 cells and SW620 cells treated with CHX for the indicated time points. f Immunofluorescence staining of Ac-K49-β-catenin (red) and β-catenin (green) in control, and Bcl-3-silenced HCT116 cells. The nuclei were stained using DAPI (blue). g Immunoblot analyses of Bcl-3, Ac-K49-β-catenin, and β-catenin in control, and Bcl-3-silenced HCT116 cells treated with or without different HDAC inhibitors for 24 h; (SAN, santacruzamate A, 1 μM; ENT, entinostat, 5 μM; TUB, tubacin, 5 μM; RES, resminostat, 1 μM; VOR, vorinostat, 10 μM; BEL, belinostat, 1 μM; and TSA, 1 μM). h Control and Bcl-3-silenced HCT116 cells were cotransfected with TOP/Flash or FOP/Flash reporter and Renilla luciferase normalization control. After HDAC inhibitor treatment for 24 h, total cell lysate was collected to measure the firefly and Renilla luciferase activities. Values are means ± SD for each cohort (n = 3). i Lysates from control and Bcl-3-silenced HCT116 cells were prepared, and anti-β-catenin antibody was used in IP followed by immunoblot using the indicated antibodies. The results were quantified by ImageJ software. The relative protein levels in the input group were normalized to GAPDH levels. The relative protein levels in the IP group were normalized to β-catenin levels. j HCT116 cells were cotransfected with the indicated siRNA and TOP/Flash or FOP/Flash reporter plasmid, and then total cell lysates were collected to measure the firefly and Renilla luciferase activities. Values are means ± SD for each cohort (n = 3). *p < 0.05, **p < 0.01, and ***p < 0.001 by two-tailed Student’s t-test