IRF11 enhances the inhibitory effect of IκBα on NF-κB activation in miiuy croaker.

NF-κB is a typical transcription factor that regulates expression of various genes involved in inflammatory and immune responses. Therefore, it is essential that NF-κB signaling tightly regulated to maintain immune balance. Compared with those of mammals, the regulatory mechanisms of NF-κB signaling is rarely reported in teleost fish. IκBα is a prominent negative feedback regulator in the NF-κB signaling system. In this study, we determined that IRF11 enhances the inhibitory effect of IκBα on NF-κB activation in teleost fish. Overexpression of IRF11 can inhibit IκBα degradation, whereas its knockdown has the opposite effect of IκBα. Our study further indicates that IκBα was regulated via ubiquitin-proteasome degradation pathway, IRF11 inhibits IκBα in ubiquitin-proteasome degradation. This study provides a novel evidence on the regulation of innate immune signaling pathways in teleost fish and thus provides new insights into the regulatory mechanisms in mammals.