Fig. 6

Model of the CPAP/HBx interaction in hepatocarcinogenesis. HBV infection triggers immune responses and later develops into chronic liver diseases, such as hepatitis, fibrosis or cirrhosis. The further production of inflammatory cytokines induced by HBx can modulate the SUMO modification of CPAP and subsequently enhance IKK-mediated NF-κB activation. a In this study, we demonstrate that HBx associates with the transcription factor CREB to up-regulate CPAP transcription. HBx promotes NF-κB activity to enhance the production of inflammatory cytokines. b Meanwhile, inflammatory cytokines increases HBx stabilization, which is enhanced by CPAP expression and dependent on NF-κB activity. c CPAP interacts with HBx to further promote HBx-induced NF-κB activation and hepatocellular transformation, finally resulting in hepatocarcinogenesis