Fig. 6: IKKβ phosphorylates ARID1A and promotes ARID1A destruction via β-TRCP.

a IB analysis of the WCL and immunoprecipitates derived from C4-2 cells treated with TNFα with or without λ-phosphatase or IKKβ oligonucleotides. b In vitro kinase assays indicated that the phosphorylation of IKKβ was required for ARID1A phosphorylation. c Sequence alignment of the putative IKKβ phosphorylation sites and β-TRCP binding motif at S1316 and S1320 of ARID1A. d In vitro kinase assays to examine the phosphorylation of S1316 and S1320 sites in ARID1A by IKKβ. e WT and mutant ARID1A cell lysates were subjected to IP with anti-ARID1A antibody and IB with anti-ubiquitin (anti-Ub) and anti-p-Ser antibody. f IB analysis of WT and mutant ARID1A cells with or without IKKβ-SD overexpression. g, h FVB mice were inoculated with WT or Arid1a^Mut Myc-CaP cells, and tumor volume (g, n = 5) and quantification of each tumor-infiltrating immune cell population (h, n = 5) were measured by FACS. i IB analysis of the WCL and immunoprecipitates derived from WT and ARID1A^Mut C4-2 cells treated with or without TNFα. j IB analysis of WT and ARID1A^Mut C4-2 cells transfected with scramble or β-TRCP oligonucleotides with or without TNFα stimulation. g, h Data represent the mean ± SEM. Statistical significance was determined by two-way ANOVA followed by multiple comparison (g) and two-tailed unpaired t-test (h). a, b, d–f, i, j Experiments were repeated three times independently with similar results; data from one representative experiment are shown. Source data are provided as a Source Data file.