Regulation of NF-kB signalling through the PR55β-RelA interaction in osteoblasts

Background/Aim: Nuclear factor kappa B (NFkB) signalling including the RelA subunit is activated upon fibroblast growth factor (FGF) stimulation. A clear understanding of the mechanisms underlying this action will provide insights into molecular targeting therapy. Furthermore, protein phosphatase 2A (PP2A) is involved in RelA dephosphorylation, but little is known about the underlying mechanism. Materials and Methods: Because the regulatory subunits of PP2A drive NF-kB signalling via RelA, we used qRT-PCR and immunoblot analysis to investigate the expression of these subunits in MC3T3-E1 cells. We examined weather FGF2 interacts with NF-kB using immunocytochemistry (IC), immunoprecipitation (IP), and pull-down assay (PD) using recombinant proteins. Results: PR55β expression was increased, whereas activated RelA was dephosphorylated upon FGF2 stimulation. Further, the interaction of PR55β with RelA was confirmed by IC, IP, and PD. Conclusion: FGF2-induced PR55β directly interacts with RelA and regulates NF-kB signalling.