The innate immune response against viral infection is mainly relies on type I interferon, the production of which is mediated by TANK-binding kinase 1 (TBK1). It is revealed that the downstream TBK1 is activated by viral nucleic acid sensors RIG-I, cGAS and TLR3. The activity of TBK1 is complexly and precisely regulated by different type of protein modifications, including phosphorylation, ubiquitination and Sumolylation. This article focuses on the role of TBK1 in anti-viral innate immunity and the regulatory mechanism for the TBK1 activation.
Humans ; Immunity, Innate ; genetics ; physiology ; Interferon Type I ; Phosphorylation ; Protein Processing, Post-Translational ; immunology ; Protein-Serine-Threonine Kinases ; chemistry ; physiology ; Signal Transduction ; Ubiquitination ; Virus Diseases ; physiopathology

Tripartite motif (TRIM) family proteins are important effectors of innate immunity against viral infections. Here we identified TRIM35 as a regulator of TRAF3 activation. Deficiency in or inhibition of TRIM35 suppressed the production of type I interferon (IFN) in response to viral infection. Trim35-deficient mice were more susceptible to influenza A virus (IAV) infection than were wild-type mice. TRIM35 promoted the RIG-I-mediated signaling by catalyzing Lys63-linked polyubiquitination of TRAF3 and the subsequent formation of a signaling complex with VISA and TBK1. IAV PB2 polymerase countered the innate antiviral immune response by impeding the Lys63-linked polyubiquitination and activation of TRAF3. TRIM35 mediated Lys48-linked polyubiquitination and proteasomal degradation of IAV PB2, thereby antagonizing its suppression of TRAF3 activation. Our in vitro and in vivo findings thus reveal novel roles of TRIM35, through catalyzing Lys63- or Lys48-linked polyubiquitination, in RIG-I antiviral immunity and mechanism of defense against IAV infection.
A549 Cells ; Animals ; Apoptosis Regulatory Proteins/immunology* ; DEAD Box Protein 58/immunology* ; Dogs ; HEK293 Cells ; Humans ; Influenza A Virus, H1N1 Subtype/immunology* ; Madin Darby Canine Kidney Cells ; Mice ; Mice, Knockout ; Orthomyxoviridae Infections/pathology* ; Proteolysis ; RAW 264.7 Cells ; Signal Transduction/immunology* ; THP-1 Cells ; TNF Receptor-Associated Factor 3/immunology* ; Ubiquitination/immunology* ; Viral Proteins/immunology*