Abstract
Type I interferons are central mediators for antiviral responses. Using high-throughput functional screening of interferon inducers, we have identified here a molecule we call interferon-beta promoter stimulator 1 (IPS-1). Overexpression of IPS-1 induced type I interferon and interferon-inducible genes through activation of IRF3, IRF7 and NF-kappaB transcription factors. TBK1 and IKKi protein kinases were required for the IPS-1-mediated interferon induction. IPS-1 contained an N-terminal CARD-like structure that mediated interaction with the CARD of RIG-I and Mda5, which are cytoplasmic RNA helicases that sense viral infection. 'Knockdown' of IPS-1 by small interfering RNA blocked interferon induction by virus infection. Thus, IPS-1 is an adaptor involved in RIG-I- and Mda5-mediated antiviral immune responses.
MeSH terms
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / metabolism*
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Amino Acid Sequence
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Animals
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Cells, Cultured
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DEAD Box Protein 58
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DEAD-box RNA Helicases
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DNA-Binding Proteins / metabolism
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Humans
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I-kappa B Kinase
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Interferon Inducers / metabolism*
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Interferon Regulatory Factor-3
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Interferon Regulatory Factor-7
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Interferon Type I / biosynthesis*
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Interferon-Induced Helicase, IFIH1
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Interferon-beta / genetics
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Mice
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Molecular Sequence Data
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NF-kappa B / metabolism
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Protein Serine-Threonine Kinases / physiology
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Protein Structure, Tertiary
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RNA Helicases / metabolism*
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RNA, Messenger / genetics
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Receptors, Immunologic
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Sequence Alignment
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Transcription Factors / metabolism
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Vesicular stomatitis Indiana virus / immunology
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Vesicular stomatitis Indiana virus / physiology
Substances
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Adaptor Proteins, Signal Transducing
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DNA-Binding Proteins
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IRF3 protein, human
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IRF7 protein, human
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Interferon Inducers
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Interferon Regulatory Factor-3
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Interferon Regulatory Factor-7
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Interferon Type I
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Irf3 protein, mouse
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Irf7 protein, mouse
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MAVS protein, human
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NF-kappa B
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RNA, Messenger
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Receptors, Immunologic
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Transcription Factors
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Interferon-beta
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Tbk1 protein, mouse
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Protein Serine-Threonine Kinases
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TBK1 protein, human
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I-kappa B Kinase
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RIGI protein, human
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IFIH1 protein, human
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DEAD Box Protein 58
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DEAD-box RNA Helicases
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Interferon-Induced Helicase, IFIH1
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RNA Helicases