casein-kinase-ii and Arthritis

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.

Topics: Animals; Arthritis; Arthritis, Experimental; Casein Kinase II; Cell Line; Chromatography, Liquid; Fusion Proteins, bcr-abl; Genes, abl; Humans; Interleukin-6; Mice; Mice, Inbred C57BL; NF-kappa B; Philadelphia Chromosome; Proto-Oncogene Proteins c-bcr; RNA, Small Interfering; Tandem Mass Spectrometry; Tumor Necrosis Factor-alpha

The physiological interaction between glycyrrhizin (GL) and serum complement C3, and the inhibitory effects of GL, glycyrrhetinic acid (GA), and a GA derivative (oGA) on the phosphorylation of C3 by casein kinase 2 (CK-2), were investigated in vitro. C3 was found to be a GL-binding protein (gbP), because (i) of its high affinity for a GL-affinity HPLC column; and (ii) both GL and GA induce conformational changes in C3. At least four trypsin-resistant fragments (p30, p25, p18, and p15) were detected when the (32)P-labeled C3alpha was digested with trypsin in the presence of 100 micro M GA. Two of these (p25 and p15) were immuno-precipitated with anti-C3a serum. Furthermore, it was found that C3a contains GL-binding domains, because (i) C3a (anaphylatoxin) could be selectively purified from the synovial fluids of patients with rheumatoid arthritis by GL-affinity column chromatography (HPLC); and (ii) purified human C3a has a high affinity for a GL-affinity column. In addition, C3alpha (p115) of C3 was effectively phosphorylated by CK-2 in the presence of poly-Arg (a CK-2 activator) in vitro. This phosphorylation was completely inhibited by 10 micro M oGA, 30 micro M GA, or 100 micro M GL. Taken together, these results suggest that the GL-induced inhibition of the physiological activities of C3a and C3alpha may be involved in the anti-inflammatory effect of GL in vivo.

Topics: Arthritis; Binding Sites; Casein Kinase II; Complement C3; Complement C3a; Glycyrrhetinic Acid; Glycyrrhiza; Glycyrrhizic Acid; Humans; Phosphorylation; Protein Binding; Protein Conformation; Protein Serine-Threonine Kinases; Synovial Fluid