Abstract
Most of NF-κB (nuclear factor kappa B) signaling molecules have various types of post-translational modifications. In this study, we focused on ubiquitination and designed a siRNA library including most ubiquitin-binding domains. With this library, we identified several candidate regulators of canonical NF-κB pathway, including RNF4. Overexpression of RNF4 impaired NF-κB activation in a dose-dependent manner, whereas RNF4 knockdown potentiated NF-κB activation. We showed that RNF4 interacts with the TAK1-TAB2-TAB3 complex, but not TAB1. Further, we found that RNF4 specifically down-regulated TAB2 through a lysosomal pathway, and knockdown of RNF4 impaired endogenous TAB2 degradation. Therefore, our findings will provide new insights into the negative regulation of NF-κB signaling.
Keywords:
IL-1β; NF-κB; RNF4; TAB2; TNFα.
Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing / metabolism*
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Animals
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Cell Line, Tumor
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Down-Regulation* / drug effects
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Gene Knockdown Techniques
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Humans
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Interleukin-1beta / pharmacology
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Lysosomes / drug effects
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Lysosomes / metabolism
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MAP Kinase Kinase Kinases / metabolism
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Mice
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NF-kappa B / metabolism*
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Nuclear Proteins / chemistry
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Nuclear Proteins / deficiency
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Protein Structure, Tertiary
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Proteolysis / drug effects
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RNA, Small Interfering / genetics
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Signal Transduction* / drug effects
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Transcription Factors / chemistry
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Transcription Factors / deficiency
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Ubiquitin / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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Interleukin-1beta
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NF-kappa B
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Nuclear Proteins
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RNA, Small Interfering
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RNF4 protein, human
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Tab2 protein, mouse
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Transcription Factors
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Ubiquitin
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MAP Kinase Kinase Kinases
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MAP kinase kinase kinase 7