Upregulation of c-Jun and JunB in ABC DLBCL cell lines is CARMA1-, MALT1-, MyD88-, IRAK1-, and TAK1-dependent. (A) Analysis of c-Jun, JunB, and JunD protein expression and c-Jun phosphorylation on Ser 63 in GCB and ABC cell lines by western blot. (B) Analysis of c-Jun, JunB, and JunD protein expression in lysates of HBL-1 (ABC) and BJAB (GCB) cell lines transduced with control small hairpin RNA (shRNA) or with CARMA1-, MALT1-, IRAK1-, or Myd88-specific shRNA. Silencing efficiency was assessed by western blot analysis using anti-CARMA1, anti-MALT1, anti-IRAK1, and anti-MyD88 antibodies. (C-D) Protein expression in GCB and ABC DLBCL cell lines was determined by western blot using the indicated antibodies. In panel C, we used lysates of Jurkat cells treated with PMA and ionomycin (PI) for 1 hour as a positive control for MAPK activation. In panel D, DLBCL cell lines of the GCB (BJAB), or ABC subtype (all others) were treated with the TAK1 inhibitor 5Z7 or with solvent alone for 24 hours. In all figure panels, blotting for tubulin served as a loading control. Data are representative of at least 3 (A-B) or 2 (C-D) independent experiments.