Abstract
Signals and posttranslational modifications regulating the decapping step in mRNA degradation pathways are poorly defined. In this study we reveal the importance of K63-linked ubiquitylation for the assembly of decapping factors, P-body formation, and constitutive decay of instable mRNAs encoding mediators of inflammation by various experimental approaches. K63-branched ubiquitin chains also regulate IL-1-inducible phosphorylation of the P-body component DCP1a. The E3 ligase TRAF6 binds to DCP1a and indirectly regulates DCP1a phosphorylation, expression of decapping factors, and gene-specific mRNA decay. Mutation of six C-terminal lysines of DCP1a suppresses decapping activity and impairs the interaction with the mRNA decay factors DCP2, EDC4, and XRN1, but not EDC3, thus remodeling P-body architecture. The usage of ubiquitin chains for the proper assembly and function of the decay-competent mammalian decapping complex suggests an additional layer of control to allow a coordinated function of decapping activities and mRNA metabolism in higher eukaryotes.
Keywords:
DCP1a; IL-1; K63R ubiquitin; P-body; TRAF6; ubiquitin.
Copyright © 2016 Elsevier Inc. All rights reserved.
MeSH terms
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Animals
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Cell Line, Tumor
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Endoribonucleases / genetics
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Endoribonucleases / metabolism*
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Exoribonucleases / metabolism
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HEK293 Cells
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Humans
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Interleukin-1alpha / pharmacology
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Intracellular Signaling Peptides and Proteins
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Lysine / metabolism*
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Mice
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Microtubule-Associated Proteins / metabolism
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Mutation
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Phosphorylation
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Protein Binding
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Protein Interaction Domains and Motifs
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Proteins / metabolism
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RNA Caps / genetics
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RNA Caps / metabolism*
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RNA Stability* / drug effects
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RNA, Messenger / genetics
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RNA, Messenger / metabolism*
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Receptors, Interleukin-1 / agonists
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Receptors, Interleukin-1 / genetics
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Receptors, Interleukin-1 / metabolism
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TNF Receptor-Associated Factor 6 / genetics
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TNF Receptor-Associated Factor 6 / metabolism*
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Time Factors
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Trans-Activators / genetics
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Trans-Activators / metabolism*
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Transfection
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Ubiquitination* / drug effects
Substances
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EDC4 protein, human
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IL1A protein, human
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Interleukin-1alpha
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Intracellular Signaling Peptides and Proteins
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Microtubule-Associated Proteins
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Proteins
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RNA Caps
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RNA, Messenger
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Receptors, Interleukin-1
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TNF Receptor-Associated Factor 6
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Tifab protein, human
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Trans-Activators
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Endoribonucleases
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Exoribonucleases
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XRN1 protein, human
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DCP1A protein, human
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DCP2 protein, human
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Lysine