Inhibition of NF-κB Activation by Peptides Targeting NF-κB Essential Modulator (NEMO) Oligomerization (original) (raw)
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Journal of Biological Chemistry, 2004
NF-B essential modulator/IKK-␥ (NEMO/IKK-␥) plays a key role in the activation of the NF-B pathway in response to proinflammatory stimuli. Previous studies suggested that the signal-dependent activation of the IKK complex involves the trimerization of NEMO. The minimal oligomerization domain of this protein consists of two coiled-coil subdomains named Coiled-coil 2 (CC2) and leucine zipper (LZ) (Agou, F., Traincard, F., Vinolo, E., Courtois, G., Yamaoka, S., Israel, A., and Veron, M. (2004) J. Biol. Chem. 279, 27861-27869).
Direct inhibition of NF-κB activation by peptide targeting the NOA ubiquitin binding domain of NEMO
2011
Aberrant and constitutive NF-kB activation are frequently reported in numerous tumor types, making its inhibition an attractive target for the treatment of certain cancers. NEMO (NF-kB essential modulator) is the crucial component of the canonical NF-kB pathway that mediates IkB kinase (IKK) complex activation. IKK activation resides in the ability of the C-terminal domain of NEMO to properly dimerize and interact with linear and K63-linked polyubiquitin chains. Here, we have identified a new NEMO peptide inhibitor, termed UBI (ubiquitin binding inhibitor) that derives from the NOA/NUB/UBAN ubiquitin binding site located in the CC2-LZ domain of NEMO. UBI specifically inhibits the NF-kB pathway at the IKK level in different cell types stimulated by a variety of NF-kB signals. Circular dichroïsm and fluorescence studies showed that UBI exhibits an increased a-helix character and direct, good-affinity binding to the NOA-LZ region of NEMO. We also showed that UBI targets NEMO in cells but its mode of inhibition is completely different from the previously reported LZ peptide (herein denoted NOA-LZ). UBI does not promote dissociation of NEMO subunits in cells but impairs the interaction between the NOA UBD of NEMO and polyubiquitin chains. Importantly, we showed that UBI efficiently competes with the in vitro binding of K63-linked chains, but not with linear chains. The identification of this new NEMO inhibitor emphasizes the important contribution of K63-linked chains for IKK activation in NF-kB signaling and would provide a new tool for studying the complex role of NF-kB in inflammation and cancer.
Proceedings of the National Academy of Sciences, 2016
Significance Regulated activation of the NF-κB family of transcription factors is important for normal development, immune cell function, and inflammatory responses. NEMO, the NF-κB essential modulator, controls activation of the canonical IKK complex and NF-κB–mediated cellular responses, but details of how this is achieved are not fully known. Our results show that C-terminal mutations in NEMO can cause hyperactivation of inflammatory responses to Toll-like receptor and TNF ligands through impaired recruitment of the negative NF-κB regulator A20/TNFAIP3. Our results help to explain the inflammatory symptoms in patients harboring these NEMO mutations. Furthermore, our findings suggest that targeting this molecular interaction by enhancing A20 expression or its recruitment to the NEMO C-terminus may be a therapeutic strategy for human inflammatory disease.
Proteins that bind to IKKγ (NEMO) and down-regulate the activation of NF-κB
Biochemical and Biophysical Research Communications, 2010
Inhibitor of jB kinase (IKK) gamma (IKKc), also referred to as nuclear factor jB (NF-jB) essential modulator (NEMO), is an important component of the IKK complex. Following the exposure of cells to NF-jBinducing stimuli, the IKK complex catalyzes the phosphorylation of inhibitor of jB (IjB) proteins, which is a critical step that leads to the activation of NF-jB via the canonical pathway. The exact functions of IKKc as part of the IKK complex have not been fully elucidated. A number of proteins have been identified as directly interacting with IKKc and modulating the activity of the IKK complex. This mini review covers eight proteins that have been reported to bind to IKKc and lead to the suppression of the activities of the IKK complex and hence result in the down-regulation of the activation of NF-jB. The reported mechanisms by which these interactions suppress the activation of the IKK complex include the deubiquitination of IKKc and competition with upstream activators for binding to IKKc.
Development of novel NEMO-binding domain mimetics for inhibiting IKK/NF-κB activation
PLoS biology, 2018
Nuclear factor κB (NF-κB) is a transcription factor important for regulating innate and adaptive immunity, cellular proliferation, apoptosis, and senescence. Dysregulation of NF-κB and its upstream regulator IκB kinase (IKK) contributes to the pathogenesis of multiple inflammatory and degenerative diseases as well as cancer. An 11-amino acid peptide containing the NF-κB essential modulator (NEMO)-binding domain (NBD) derived from the C-terminus of β subunit of IKK, functions as a highly selective inhibitor of the IKK complex by disrupting the association of IKKβ and the IKKγ subunit NEMO. A structure-based pharmacophore model was developed to identify NBD mimetics by in silico screening. Two optimized lead NBD mimetics, SR12343 and SR12460, inhibited tumor necrosis factor α (TNF-α)- and lipopolysaccharide (LPS)-induced NF-κB activation by blocking the interaction between IKKβ and NEMO and suppressed LPS-induced acute pulmonary inflammation in mice. Chronic treatment of a mouse model...
Involvement of linear polyubiquitylation of NEMO in NF-κB activation
Nature Cell Biology, 2009
Nuclear factor-κB (NF-κB) is a key transcription factor in inflammatory, anti-apoptotic and immune processes. The ubiquitin pathway is crucial in regulating the NF-κB pathway. We have found that the LUBAC ligase complex, composed of the two RING finger proteins HOIL-1L and HOIP, conjugates a head-to-tail-linked linear polyubiquitin chain to substrates. Here, we demonstrate that LUBAC activates the canonical NF-κB pathway by binding to NEMO (NF-κB essential modulator, also called IKKγ) and conjugates linear polyubiquitin chains onto specific Lys residues in the CC2-LZ domain of NEMO in a Ubc13-independent manner. Moreover, in HOIL-1 knockout mice and cells derived from these mice, NF-κB signalling induced by pro-inflammatory cytokines such as TNF-α and IL-1β was suppressed, resulting in enhanced TNF-α-induced apoptosis in hepatocytes of HOIL-1 knockout mice. These results indicate that LUBAC is involved in the physiological regulation of the canonical NF-κB activation pathway through linear polyubiquitylation of NEMO.
IKKα, IKKβ, and NEMO/IKKγ Are Each Required for the NF-κB-mediated Inflammatory Response Program
Journal of Biological Chemistry, 2002
The IKK and NEMO/IKK␥ subunits of the NF-B-activating signalsome complex are known to be essential for activating NF-B by inflammatory and other stresslike stimuli. However, the IKK␣ subunit is believed to be dispensable for the latter responses and instead functions as an in vivo mediator of other novel NF-B-dependent and-independent functions. In contrast to this generally accepted view of IKK␣'s physiological functions, we demonstrate in mouse embryonic fibroblasts (MEFs) that, akin to IKK and NEMO/IKK␥, IKK␣ is also a global regulator of tumor necrosis factor ␣and IL-1responsive IKK signalsome-dependent target genes including many known NF-B targets such as serum amyloid A3, C3, interleukin (IL)-6, IL-11, IL-1 receptor antagonist, vascular endothelial growth factor, Ptx3,  2microglobulin, IL-1␣, Mcp-1 and-3, RANTES (regulated on activation normal T cell expressed and secreted), Fas antigen, Jun-B, c-Fos, macrophage colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor. Only a small number of NF-B-dependent target genes were preferentially dependent on IKK␣ or IKK. Constitutive expression of a trans-dominant IB␣ superrepressor (IB␣SR) in wild type MEFs confirmed that these signalsome-dependent target genes were also dependent on NF-B. A subset of NF-B target genes were IKK-dependent in the absence of exogenous stimuli, suggesting that the signalsome was also required to regulate basal levels of activated NF-B in established MEFs. Overall, a sizable number of novel NF-B/IKK-dependent genes were identified including Secreted Frizzled, cadherin 13, protocadherin 7, CCAAT/enhancer-binding protein- and-␦, osteoprotegerin, FOXC2 and FOXF2, BMP-2, p75 neurotrophin receptor, caspase-11, guanylate-binding proteins 1 and 2, ApoJ/clusterin, interferon (␣ and ) receptor 2, decorin, osteoglycin, epiregulin, proliferins 2 and 3, stromal cell-derived factor, and cathepsins B, F, and Z. SOCS-3, a negative effector of STAT3 signaling, was found to be an NF-B/IKK-induced gene, suggesting that IKKmediated NF-B activation can coordinately illicit negative effects on STAT signaling.
N4BP1 negatively regulates NF-κB by binding and inhibiting NEMO oligomerization
Nature Communications, 2021
Many immune responses depend upon activation of NF-κB, an important transcription factor in the elicitation of a cytokine response. Here we show that N4BP1 inhibits TLR-dependent activation of NF-κB by interacting with the NF-κB signaling essential modulator (NEMO, also known as IκB kinase γ) to attenuate NEMO–NEMO dimerization or oligomerization. The UBA-like (ubiquitin associated-like) and CUE-like (ubiquitin conjugation to ER degradation-like) domains in N4BP1 mediate interaction with the NEMO COZI domain. Both in vitro and in mice, N4bp1 deficiency specifically enhances TRIF-independent (TLR2, TLR7, or TLR9-mediated) but not TRIF-dependent (TLR3 or TLR4-mediated) NF-κB activation, leading to increased production of proinflammatory cytokines. In response to TLR4 or TLR3 activation, TRIF causes activation of caspase-8, which cleaves N4BP1 distal to residues D424 and D490 and abolishes its inhibitory effect. N4bp1−/− mice also have diminished numbers of T cells in the peripheral bl...