Multiple signaling pathways leading to the activation of interferon regulatory factor 3.
Virus infection of susceptible cells activates multiple signaling pathways that orchestrate the activation of genes, such as cytokines, involved in the antiviral and innate immune response. Among the kinases induced are the mitogen-activated protein (MAP) kinases, Jun-amino terminal kinases (JNK) and p38, the IkappaB kinase (IKK) and DNA-PK. In addition, virus infection also activates an uncharacterized VAK responsible for the C-terminal phosphorylation and subsequent activation of interferon regulatory factor 3 (IRF-3). Virus-mediated activation of IRF-3 through VAK is dependent on viral entry and transcription, since replication deficient virus failed to induce IRF-3 activity. The pathways leading to VAK activation are not well characterized, but IRF-3 appears to represent a novel cellular detection pathway that recognizes viral nucleocapsid (N) structure. Recently, the range of inducers responsible for IRF-3 activation has increased. In addition to virus infection, recognition of bacterial infection mediated through lipopolysaccharide by Toll-like receptor 4 has also been reported. Furthermore, MAP kinase kinase kinase (MAP KKK)-related pathways and DNA-PK induce N-terminal phosphorylation of IRF-3. This review summarizes recent observations in the identification of novel signaling pathways leading to IRF-3 activation.
Servant
Marc J
MJ
Terry Fox Molecular Oncology Group, Lady Davis Institute-Jewish General Hospital, McGill University, 3755 Cote Ste., Catherine Montreal, Que., Canada.
Grandvaux
Nathalie
N
Hiscott
John
J
D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D050838:Interferon Regulatory Factor-3; D008070:Lipopolysaccharides / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D012330:RNA, Double-Stranded / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013312:Stress, Physiological / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014777:Virus Diseases / Q000378:metabolism; D014780:Viruses / Q000378:metabolism
D004268:DNA-Binding Proteins; C494232:IRF3 protein, human; D050838:Interferon Regulatory Factor-3; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012330:RNA, Double-Stranded; D014157:Transcription Factors