Breakpoint Cluster Region–Mediated Inflammation Is Dependent on Casein Kinase II

Abstract The breakpoint cluster region (BCR) is known as a kinase and cause of leukemia upon fusing to Abl kinase. In this study, we demonstrate that BCR associated with the α subunit of casein kinase II (CK2α), rather than BCR itself, is required for inflammation development. We found that BCR knockdown inhibited NF-κB activation in vitro and in vivo. Computer simulation, however, suggested that the putative BCR kinase domain has an unstable structure with minimal enzymatic activity. Liquid chromatography–tandem mass spectrometry analysis showed that CK2α associated with BCR. We found the BCR functions are mediated by CK2α. Indeed, CK2α associated with adaptor molecules of TNF-αR and phosphorylated BCR at Y177 to establish a p65 binding site after TNF-α stimulation. Notably, p65 S529 phosphorylation by CK2α creates a p300 binding site and increased p65-mediated transcription followed by inflammation development in vivo. These results suggest that BCR-mediated inflammation is dependent on CK2α, and the BCR–CK2α complex could be a novel therapeutic target for various inflammatory diseases.