Abstract
ProIL-1beta is a proinflammatory cytokine that is proteolytically processed to its active form by caspase-1. Upon receipt of a proinflammatory stimulus, an upstream adaptor, RIP2, binds and oligomerizes caspase-1 zymogen, promoting its autoactivation. ICEBERG is a novel protein that inhibits generation of IL-1beta by interacting with caspase-1 and preventing its association with RIP2. ICEBERG is induced by proinflammatory stimuli, suggesting that it may be part of a negative feedback loop. Consistent with this, enforced retroviral expression of ICEBERG inhibits lipopolysaccharide-induced IL-1beta generation. The structure of ICEBERG reveals it to be a member of the death-domain-fold superfamily. The distribution of surface charge is complementary to the homologous prodomain of caspase-1, suggesting that charge-charge interactions mediate binding of ICEBERG to the prodomain of caspase-1.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence / physiology*
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Carrier Proteins / genetics*
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Caspase 1 / chemistry
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Caspase 1 / metabolism*
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Cells, Cultured
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Inflammation Mediators / metabolism*
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Interleukin-1 / antagonists & inhibitors*
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Interleukin-1 / biosynthesis*
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Intracellular Signaling Peptides and Proteins*
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Molecular Sequence Data
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Monomeric GTP-Binding Proteins / metabolism
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Monomeric GTP-Binding Proteins / pharmacology
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Protein Serine-Threonine Kinases / chemistry
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Protein Serine-Threonine Kinases / metabolism*
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Receptor-Interacting Protein Serine-Threonine Kinase 2
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Receptor-Interacting Protein Serine-Threonine Kinases
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Sequence Analysis, Protein
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Tumor Necrosis Factor-alpha / metabolism
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Tumor Necrosis Factor-alpha / pharmacology
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ran GTP-Binding Protein
Substances
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CARD18 protein, human
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Carrier Proteins
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Inflammation Mediators
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Interleukin-1
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Intracellular Signaling Peptides and Proteins
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Ran protein, mouse
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Tumor Necrosis Factor-alpha
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Protein Serine-Threonine Kinases
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RIPK2 protein, human
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Receptor-Interacting Protein Serine-Threonine Kinase 2
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Receptor-Interacting Protein Serine-Threonine Kinases
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Ripk2 protein, mouse
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Caspase 1
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Monomeric GTP-Binding Proteins
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ran GTP-Binding Protein
Associated data
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GENBANK/AF208005
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PDB/1DGN