Abstract
The serine/threonine kinase RIPK1 is recruited to TNFR1 to mediate proinflammatory signaling and to regulate TNF-induced cell death. A RIPK1 deficiency results in perinatal lethality, impaired NFκB and MAPK signaling, and sensitivity to TNF-induced apoptosis. Chemical inhibitor and in vitro-reconstitution studies suggested that RIPK1 displays distinct kinase activity-dependent and -independent functions. To determine the contribution of RIPK1 kinase to inflammation in vivo, we generated knock-in mice endogenously expressing catalytically inactive RIPK1 D138N. Unlike Ripk1(-/-) mice, which die shortly after birth, Ripk1(D138N/D138N) mice are viable. Cells expressing RIPK1 D138N are resistant to TNF- and polyinosinic-polycytidylic acid-induced necroptosis in vitro, and Ripk1(D138N/D138N) mice are protected from TNF-induced shock in vivo. Moreover, Ripk1(D138N/D138N) mice fail to control vaccinia virus replication in vivo. This study provides genetic evidence that the kinase activity of RIPK1 is not required for survival but is essential for TNF-, TRIF-, and viral-initiated necroptosis.
Copyright © 2014 by The American Association of Immunologists, Inc.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Vesicular Transport / immunology
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Animals
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Apoptosis / drug effects
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Apoptosis / immunology*
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Cells, Cultured
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Gene Knock-In Techniques
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Hypothermia / chemically induced
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Hypothermia / mortality*
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Inflammation / genetics
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Inflammation / immunology
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MAP Kinase Signaling System / immunology
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Macrophages / immunology
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Mice
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Mice, Inbred C57BL
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NF-kappa B / immunology
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Necrosis / chemically induced
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Necrosis / immunology*
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Poly I-C / pharmacology
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Receptor-Interacting Protein Serine-Threonine Kinases / genetics*
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Receptor-Interacting Protein Serine-Threonine Kinases / immunology
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Receptors, Tumor Necrosis Factor, Type I / immunology
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Tumor Necrosis Factor-alpha / immunology
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Tumor Necrosis Factor-alpha / pharmacology*
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Vaccinia / immunology
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Vaccinia virus / growth & development
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Vaccinia virus / immunology
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Virus Replication / immunology
Substances
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Adaptor Proteins, Vesicular Transport
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NF-kappa B
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Receptors, Tumor Necrosis Factor, Type I
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TICAM-1 protein, mouse
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Tnfrsf1a protein, mouse
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Tumor Necrosis Factor-alpha
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Receptor-Interacting Protein Serine-Threonine Kinases
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Ripk1 protein, mouse
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Ripk3 protein, mouse
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Poly I-C