Identification of multifunctionality of grass carp (Ctenopharyngodon idella) TBK1 during bacterial infection

TBK1 is an atypical I kappa B kinase family member with a set of functions. It is involved in congenital immunization and autophagy in mammals. In this study, we reported that grass carp TBK1 gene expression could be upregu-lated by bacterial infection. Overexpression of TBK1 could decrease the number of adhesive bacteria in CIK cells. TBK1 could promote cellular migration, proliferation, vitality, and anti-apoptosis ability. Furthermore, the expression of TBK1 could activate the NF-kappa B signaling pathway by inducing inflammatory cytokines. In addition, we found that the grass carp TBK1 could cause the autophagy level of CIK cells within the decreasing level of p62 protein. Our finding indicated that TBK1 participated in grass carp innate immune progress and autophagy. This study provides evidence of the positive regulation of TBK1 in teleost innate immunity with its multiple functions. It thus may provide important information about the defense and immune mechanisms used by teleost against pathogens.