GSK5182 blocks RANKL-stimulated NF-κB, JNK, and ERK activation. (A and B) BMMs were serum-starved for 6 h, pretreated with GSK5182 (10 μM) or vehicle (control) for 1 h, and then stimulated with RANKL (30 ng/ml). (A) We assayed total protein extracts by immunoblotting to detect phosphorylated and total MAPK (JNK, ERK, p38) proteins. (B) Cell lysates were immunoblotted with a phospho-IκBα antibody. (C) IκBα protein levels in GSK5182-treated cells. (D, E) RAW264.7 cells were transfected with NF-κB luciferase reporter alone (D) or co-transfected with NF-κB luciferase together with the ERRγ expression plasmid (E). After transfection, we treated cells with the indicated concentrations of GSK5182 or vehicle for 24 h and then stimulated them with RANKL (100 ng/ml) for 24 h. We measured NF-κB luciferase activity using a dual-luciferase reporter assay system. **P < 0.001.