Direct activation of protein kinases by unanchored polyubiquitin chains

Xia, Zong Ping; Sun, Lijun; Chen, Xiang; Pineda, Gabriel; Jiang, Xiaomo; Adhikari, Anirban; Zeng, Wenwen; Chen, Zhijian J.

doi:10.1038/nature08247

Cited by 491 publications

(522 citation statements)

References 30 publications

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“…Although ATM is predominantly a nuclear kinase, a small quantity of ATM can be detected in the cytosol (Fig. 4D) (29). When TAK1 was immunoprecipitated from the cytosolic fractions, we found that etoposide treatment induced interactions between TAK1 and cytosolic ATM (Fig.…”

Section: Resultsmentioning

confidence: 84%

“…Treatment with proinflammatory cytokine TNF-␣ or IL-1␤ has been shown to stimulate TAK1 kinase activity, which can be detected using an in vitro kinase assay or by probing cell lysates with an anti-phospho-TAK1 antibody to measure TAK1 autophosphorylation (21,29). To determine whether DNA damage stimulates TAK1 kinase activity, we treated the human tumor cell line U2OS with TNF-␣, doxorubicin, etoposide, or gamma irradiation for the time periods indicated in Fig.…”

Section: Resultsmentioning

confidence: 99%

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A Cytosolic ATM/NEMO/RIP1 Complex Recruits TAK1 To Mediate the NF-κB and p38 Mitogen-Activated Protein Kinase (MAPK)/MAPK-Activated Protein 2 Responses to DNA Damage

Yang

Xia

Hermance

et al. 2011

Molecular and Cellular Biology

123

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In multiple tumor types, activation of the transcription factor NF-B increases the resistance of tumor cells to anticancer therapies and contributes to tumor progression. Genotoxic stress induced by chemotherapy or radiation therapy triggers the ATM-dependent translocation of NF-B essential modifier (NEMO), also designated I B kinase ␥ (IKK␥), from the nucleus to the cytosol, resulting in I B kinase activation by mechanisms not yet fully understood. RIP1 has been implicated in this response and found to be modified in cells with damaged DNA; however, the nature of the RIP1 modification and its precise role in the pathway remain unclear. Here, we show that DNA damage stimulates the formation of a cytosolic complex containing ATM, NEMO (IKK␥), RIP1, and TAK1. We find that RIP1 is modified by SUMO-1 and ubiquitin in response to DNA damage and demonstrate that modified RIP1 is required for NF-B activation and tumor cell survival. We show that ATM activates TAK1 in a manner dependent on RIP1 and NEMO. We also reveal TAK1 as a central mediator of the alternative DNA damage response pathway mediated by the p38 mitogen-activated protein kinase (MAPK)/MAPK-activated protein 2 (MAPKAP-2) kinases. These findings have translational implications and reveal RIP1 and TAK1 as potential therapeutic targets in chemoresistance.The DNA damage response activates cell cycle checkpoint and survival pathways that function to prevent DNA replication until damaged DNA is repaired. These pathways include the well-characterized ATM (ataxia telangiectasia mutated)/ CHK2 and ATR (ataxia telangiectasia and Rad-3 related)/ CHK1 pathways and the more recently identified ATM/ ATR/p38 mitogen-activated protein kinase (MAPK)/MAPKactivated protein 2 (MAPKAP-2; hereinafter called MK2) checkpoint that is active in p53-deficient tumor cells (15,19). The transcription factor NF-B regulates apoptosis induced by genotoxic stress and is an attractive therapeutic target in tumor cells whose response to DNA-damaging agents is impaired due to compromised p53 function. Moreover, constitutive NF-B activity is a hallmark of several cancers, and mutations in NF-B pathway components have been associated with the activated B cell (ABC) subtype of diffuse large B cell lymphoma (DLBCL), breast cancer, and multiple myeloma (3, 6). Thus, the inclusion of NF-B inhibitors in cancer therapy could have antioncogenic activities as well as augment the tumor chemotherapeutic response.NF-B is normally held in the cytoplasm in an inactive form bound to inhibitor proteins, such as I B␣. Diverse stimuli, such as infection, proinflammatory cytokine production, or treatment with agents that induce DNA damage elicit NF-B-mediated transcriptional activity by activating the cytosolic I B kinase (IKK) complex, consisting of IKK␣ and IKK␤ and a regulatory subunit designated IKK␥ or NF-B essential modifier (NEMO) (hereinafter referred to as NEMO). IKK activation results in I B␣ phosphorylation, ubiquitination, and subsequent degradation. The NF-B (p65/p50) heterodimer is then free to en...

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

A Cytosolic ATM/NEMO/RIP1 Complex Recruits TAK1 To Mediate the NF-κB and p38 Mitogen-Activated Protein Kinase (MAPK)/MAPK-Activated Protein 2 Responses to DNA Damage

Yang

Xia

Hermance

et al. 2011

Molecular and Cellular Biology

123

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“…[66][67][68] Alternatively, TAK1 might be activated by autophosphorylation induced by binding of TAB2 to free Lys63-linked ubiquitin chains synthesized by TRAF6. 69 NEMO (NF-kB essential modulator), through similar Lys63-linked ubiquitin chain binding properties, might also be recruited to TRAF6, resulting in its ubiquitination. 70,71 Another example for self-ubiquitination-dependent recruitment of substrates was reported for NEDD4: its self-catalyzed monoubiquitination serves to recruit EPS15, which is subsequently also monoubiquitinated by NEDD4.…”

Section: Non-proteolytic Functions Of Self-ubiquitination Of E3smentioning

confidence: 99%

Ubiquitination of E3 ligases: self-regulation of the ubiquitin system via proteolytic and non-proteolytic mechanisms

2011

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Ubiquitin modification of many cellular proteins targets them for proteasomal degradation, but in addition can also serve non-proteolytic functions. Over the last years, a significant progress has been made in our understanding of how modification of the substrates of the ubiquitin system is regulated. However, little is known on how the ubiquitin system that is comprised of B1500 components is regulated. Here, we discuss how the biggest subfamily within the system, that of the E3 ubiquitin ligases that endow the system with its high specificity towards the numerous substrates, is regulated and in particular via self-regulation mediated by ubiquitin modification. Ligases can be targeted for degradation in a self-catalyzed manner, or through modification mediated by an external ligase(s). In addition, non-proteolytic functions of self-ubiquitination, for example activation of the ligase, of E3s are discussed. Cell Death and Differentiation (2011) 18, 1393-1402 doi:10.1038/cdd.2011; published online 4 March 2011One of the major roles of the covalent modification of cellular proteins by ubiquitin is signaling them for proteasomal degradation ( Figure 1). The first step of the modification is catalyzed by the ubiquitin-activating enzyme, E1, which generates a high-energy thiol ester intermediate that is subsequently transferred to the second enzyme, a ubiquitinconjugating enzyme, E2. The third step ascertains substrate specificity, and is catalyzed by one of the numerous (B650) ubiquitin ligases, E3s. Typically, it results in the formation of an isopeptide bond between the C-terminal Gly of ubiquitin and an e-NH 2 group of an internal Lys of the substrate. Less frequently, it can generate a linear peptide bond with the a-NH 2 group, a thiol ester bond with an internal Cys, or an ester bond with a Thr or Ser. The three-step cascade of reactions is repeated, where additional ubiquitin moieties are attached sequentially to one another in an isopeptide bond involving one of the seven internal Lys residues in the ubiquitin moiety, thus generating a polyubiquitin chain. Lys48-based chains serve as a signal for proteasomal degradation, whereas chains based on other internal Lys residues, or modification by single moiety(ies) can serve non-proteolytic functions.Ligases fall into two main families: RING (really interesting new gene) and HECT (homologous to the E6-AP carboxy terminus) domain-containing E3s. RING ligases serve as scaffolds that facilitate direct transfer of ubiquitin from the E2 to the target protein. HECT E3s contain an active Cys residue to which ubiquitin binds prior to its transfer to the substrate (Figure 1). There are B600 RING finger and B30 HECT ligases in humans. Smaller families of ligases (U-box, plant homology domain, and zinc finger) have also been described.An important problem relates to regulation of the ubiquitin system components, and in particular to that of the ligases that are the specific substrate-recognizing elements. 1,2 Phosphorylation of an E3 can activate the protein, such as the ca...

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“…In the MyD88-dependent pathway, an E3 ubiquitin ligase TRAF6, generates K63-linked polyubiquitin (K63-pUb) chains, which activate the protein kinase TAK1 (4,5). These K63-pUb chains also interact with NFκB essential modulator (NEMO), a component of the canonical IKK complex (6, 7), inducing a conformational change that facilitates the activation of this complex by TAK1 and by autophosphorylation (8,9). Subsequently, the canonical IKKs (IKKα and IKKβ) activate downstream targets, which include the protein kinase Tpl2 (10,11) and the transcription factor NFκB (12) stimulating the production and secretion of inflammatory mediators, such as TNFα, IL-6, and IL-12.…”

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confidence: 99%

The TRAF-associated protein TANK facilitates cross-talk within the IκB kinase family during Toll-like receptor signaling

Clark

Takeuchi

Akira

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

113

107

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Toll-like receptor (TLR) ligands that signal via TIR-domain-containing adapter-inducing IFNβ (TRIF) activate the IκB kinase (IKK)-related kinases, TRAF associated NFκB activator (TANK)-binding kinase-1 (TBK1) and IKKε, which then phosphorylate IRF3 and induce the production of IFNβ. Here we show that TBK1 and IKKε are also activated by TLR ligands that signal via MyD88. Notably, the activation of IKKε is rapid, transient, and it precedes a more prolonged activation of TBK1. The MyD88-and TRIF-dependent signaling pathways activate the IKK-related kinases by two signaling pathways. One is mediated by the canonical IKKs, whereas the other culminates in the autoactivation of the IKK-related kinases. Once activated, TBK1/IKKε then phosphorylate and inhibit the canonical IKKs. The negative regulation of the canonical IKKs by the IKK-related kinases occurs in both the TRIF-and MyD88-dependent TLR pathways, whereas IRF3 phosphorylation is restricted to the TRIF-dependent signaling pathway. We have discovered that the activation of IKKε is abolished, the activation of TBK1 is reduced, and the interaction between the IKK-related kinases and the canonical IKKs is suppressed in TANK −/− macrophages, preventing the IKK-related kinases from negatively regulating the canonical IKKs. In contrast, IRF3 phosphorylation and IFNβ production was normal in TANK −/− macrophages. Our results demonstrate a key role for TANK in enabling the canonical IKKs and the IKK-related kinases to regulate each other, which is required to limit the strength of TLR signaling and ultimately, prevent autoimmunity.

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Direct activation of protein kinases by unanchored polyubiquitin chains

Cited by 491 publications

References 30 publications

A Cytosolic ATM/NEMO/RIP1 Complex Recruits TAK1 To Mediate the NF-κB and p38 Mitogen-Activated Protein Kinase (MAPK)/MAPK-Activated Protein 2 Responses to DNA Damage

A Cytosolic ATM/NEMO/RIP1 Complex Recruits TAK1 To Mediate the NF-κB and p38 Mitogen-Activated Protein Kinase (MAPK)/MAPK-Activated Protein 2 Responses to DNA Damage

Ubiquitination of E3 ligases: self-regulation of the ubiquitin system via proteolytic and non-proteolytic mechanisms

The TRAF-associated protein TANK facilitates cross-talk within the IκB kinase family during Toll-like receptor signaling

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