A Structural Basis for IκB Kinase 2 Activation Via Oligomerization-Dependent Trans Auto-Phosphorylation

Polley, Smarajit; Huang, De-Bin; Hauenstein, Arthur V.; Fusco, Amanda J.; Zhong, Xiang-Yang; Vu, Don; Schröfelbauer, Bärbel; Kim, Young Chang; Hoffmann, Alexander; Verma, Inder M.; Ghosh, Gourisankar; Huxford, Tom

doi:10.1371/journal.pbio.1001581

Cited by 98 publications

(156 citation statements)

References 39 publications

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“…In some cases, as exemplified by ASK2, the MAP3Ks themselves may lose their catalytic activity and become obligate dimerization partners that enhance the activation of other related MAP3Ks (38,39). MAP3K full activation also requires activation loop autophosphorylation, presumably in trans, through a transient tetrameric complex (similar to the IB kinases [IKKs]) (40,41). This phosphorylation of MAP3Ks increases and stabilizes their activity, removing the requirement of a dimeric state for substrate phosphorylation.…”

Section: Figmentioning

confidence: 99%

JNK Signaling: Regulation and Functions Based on Complex Protein-Protein Partnerships

Zeke

Misheva

Reményi

et al. 2016

Microbiol Mol Biol Rev

386

350

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SUMMARYThe c-Jun N-terminal kinases (JNKs), as members of the mitogen-activated protein kinase (MAPK) family, mediate eukaryotic cell responses to a wide range of abiotic and biotic stress insults. JNKs also regulate important physiological processes, including neuronal functions, immunological actions, and embryonic development, via their impact on gene expression, cytoskeletal protein dynamics, and cell death/survival pathways. Although the JNK pathway has been under study for >20 years, its complexity is still perplexing, with multiple protein partners of JNKs underlying the diversity of actions. Here we review the current knowledge of JNK structure and isoforms as well as the partnerships of JNKs with a range of intracellular proteins. Many of these proteins are direct substrates of the JNKs. We analyzed almost 100 of these target proteins in detail within a framework of their classification based on their regulation by JNKs. Examples of these JNK substrates include a diverse assortment of nuclear transcription factors (Jun, ATF2, Myc, Elk1), cytoplasmic proteins involved in cytoskeleton regulation (DCX, Tau, WDR62) or vesicular transport (JIP1, JIP3), cell membrane receptors (BMPR2), and mitochondrial proteins (Mcl1, Bim). In addition, because upstream signaling components impact JNK activity, we critically assessed the involvement of signaling scaffolds and the roles of feedback mechanisms in the JNK pathway. Despite a clarification of many regulatory events in JNK-dependent signaling during the past decade, many other structural and mechanistic insights are just beginning to be revealed. These advances open new opportunities to understand the role of JNK signaling in diverse physiological and pathophysiological states.

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Section: Figmentioning

confidence: 99%

JNK Signaling: Regulation and Functions Based on Complex Protein-Protein Partnerships

Zeke

Misheva

Reményi

et al. 2016

Microbiol Mol Biol Rev

386

350

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“…However, the F305A NEMO mutation, which abolishes NEMO binding to both linear and Lys63-linked chains almost completely (24), strongly suppressed IL-1␤-induced NF-B activation, confirming the importance of ubiquitin binding by NEMO for NF-B activation. These results suggested that IKK2, a crucial kinase within the IKK complex that phosphorylates IB␣, homodimerizes via its kinase domain (KD), leading to activation of IKK via trans autophosphorylation (30). We examined the involvement of KD homodimerization of IKK2 in the activation of IKK provoked by linearly ubiquitinated NEMO.…”

Section: Ikk Is Effectively Activated By Linear Polyubiquitin Conjugamentioning

confidence: 99%

“…We examined the involvement of KD homodimerization of IKK2 in the activation of IKK provoked by linearly ubiquitinated NEMO. Val229, His232, Tyr294, Gly295, and Pro296 of human IKK2 are involved in the KD-KD interaction of IKK2 (30). Therefore, we mutated Val229 and His232 to Ala (V229A/H232A); in another construct, Tyr294, Gly295, and Pro296 were mutated to Leu, Lys, and Gln, respectively, the corresponding amino acids in IKK1 (Y294L/G295K/P296Q) (30).…”

Section: Ikk Is Effectively Activated By Linear Polyubiquitin Conjugamentioning

confidence: 99%

Mechanism Underlying IκB Kinase Activation Mediated by the Linear Ubiquitin Chain Assembly Complex

Fujita

Rahighi

Akita

et al. 2014

Molecular and Cellular Biology

110

122

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N uclear factor B (NF-B) is a family of transcription factors that play essential roles in many biological phenomena, including inflammatory responses, cell survival, and innate and acquired immune responses (1). Because aberrant activation of NF-B signaling is associated with many pathological conditions, such as autoinflammatory diseases and malignancies (2, 3), signalinduced activation of NF-B has been studied extensively (4). In resting cells, inactive NF-B resides in the cytoplasm bound to its inhibitor proteins, the inhibitors of B (IBs). Stimulation by inflammatory cytokines activates the IB kinase (IKK) complex, composed of IKK1, IKK2, and NF-B essential modulator (NEMO). Following phosphorylation by activated IKK, IBs are degraded by the proteasome, leading to the release of NF-B, which then translocates to the nucleus to induce transcription of its target genes (5).The ubiquitin (Ub) conjugation system is deeply involved in the regulation of NF-B pathway (6). Recent studies showed that the linear ubiquitin chain assembly complex (LUBAC) ligase, which specifically generates linear polyubiquitin chains, is involved in NF-B activation (7,8). LUBAC is composed of three subunits: HOIP, HOIL-1L, and SHARPIN. Patients lacking HOIL-1L and mice lacking SHARPIN exhibit immunodeficiency and chronic inflammation, demonstrating the physiological significance of LUBAC-mediated linear polyubiquitination (9-12). In cells from mice lacking HOIL-1L or SHARPIN, the level of the residual LUBAC complex (consisting of the remaining two components) is reduced, and tumor necrosis factor alpha (TNF-␣)-induced NF-B activation is sharply attenuated (9-12). Although NEMO is a target of linear polyubiquitination by LUBAC, it is not yet clear how linear polyubiquitination of NEMO triggers IKK activation.In this study, using an in vitro LUBAC-mediated IKK activation assay, we found that linear diubiquitin conjugation to NEMO potently induces IKK activation. We then dissected the molecular mechanism underlying linear polyubiquitination of NEMO by LUBAC and found that the NPL4 zinc finger 1 (NZF1) domain of HOIP is responsible for recognition of a region in the coiled-coil 2 and leucine zipper (CoZi) domains of NEMO. Mutational analyses based on a cocrystal structure of HOIP NZF1 and NEMO CoZi revealed that HOIP NZF1 binds to NEMO and ubiquitin simultaneously and that both interactions are involved in linear polyubiquitination of NEMO, IKK activation, and subsequent activation of NF-B. Finally, we showed that homodimerization of IKK2 is involved in linear ubiquitin chain-mediated IKK activation. Taken together, our results suggest that recognition of linear polyubiquitins conjugated to NEMO, possibly by NEMO in another IKK complex, triggers activation of IKK2 by trans autophosphorylation. MATERIALS AND METHODS RT-PCR and plasmids.The open reading frames (ORFs) of mouse HOIP and NEMO were amplified by reverse transcription-PCR (RT-PCR) of total RNA from C57BL/6 mouse liver. Other cDNAs used in this study were described previously (8, 1...

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“…In general, phosphorylation of kinases is mediated either by trans-autophosphorylation or by upstream kinases [ 18 ]. The crystal structural analyses of human IKK2 revealed that homotypic interaction of the IKK2 kinase domain is crucial for IKK2 activation [ 19 ]. Moreover, NEMO possesses the ubiquitin binding activity that prefers linear di-ubiquitin, and NEMO's ubiquitin binding activity is critical for IKK activation [ 20 ].…”

Section: Mechanism Underlying Linear Ubiquitin Chain-mediated Nf-κb Amentioning

confidence: 99%

Linear Polyubiquitination: A Crucial Regulator of NF-κB Activation

Iwaï

2015

Innovative Medicine

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NF-κB is a transcription factor known to be involved in pleomorphic biological phenomena such as infl ammation and immune responses. Abnormal activation of NF-κB has been reported in many pathological conditions, including malignant tumors. Therefore, the NF-κB activation pathway has been extensively studied and involvement of the ubiquitin conjugation system in the NF-κB activation pathways has been revealed. Although the ubiquitin conjugation system was discovered as a part of a protein degradation pathway, non-degradable roles of the ubiquitin system have been revealed recently. Several types of polyubiquitin chains exist in cells and the type of chain seems to determine how ubiquitinated proteins are regulated. We have identifi ed that a new type of polyubiquitin chain, the linear polyubiquitin chain, plays a crucial role in regulating the NF-κB activation pathway in non-degradable manner. In this chapter, the discovery, roles in NF-κB activation, and involvement in the pathogenesis of cancers of linear ubiquitination will be discussed. Keywords NF-κB • Ubiquitin • LUBAC • Linear ubiquitin chain • cpdm • B cell lymphoma The Ubiquitin Conjugation SystemThe ubiquitin system, which is one of the most extensively studied post-translational protein modifi cation systems, has been identifi ed as part of an energy-dependent degradation system [ 1 ]. Ubiquitin is a protein-based modifi er composed of 76 amino acids. Through the function of three enzymes called the ubiquitin-activating enzyme (E1), the ubiquitin conjugating enzyme (E2) and the ubiquitin ligase (E3), ubiquitin is conjugated to the substrate proteins that are recognized by E3s. Ubiquitin is added onto ubiquitin pre-conjugated to the substrates to generate polyubiquitin chains-polymer of ubiquitin. The proteasome recognizes the polyubiquitin chains

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A Structural Basis for IκB Kinase 2 Activation Via Oligomerization-Dependent Trans Auto-Phosphorylation

Abstract: Conformational change in human IKK2 permits dimers to form higher-order oligomers that support interaction between kinase domains and promote activation through trans auto-phosphorylation.

Cited by 98 publications

References 39 publications

JNK Signaling: Regulation and Functions Based on Complex Protein-Protein Partnerships

JNK Signaling: Regulation and Functions Based on Complex Protein-Protein Partnerships

Mechanism Underlying IκB Kinase Activation Mediated by the Linear Ubiquitin Chain Assembly Complex

Linear Polyubiquitination: A Crucial Regulator of NF-κB Activation

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