Priming IKKβ kinase for action

2014 ◽  
Vol 463 (1) ◽  
pp. e1-e2 ◽  
Author(s):  
Steven C. Ley ◽  
Rudi Beyaert
Keyword(s):  
Transforming Growth Factor ◽  
Interleukin 1 ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Kinase Domain ◽  
Activation Loop ◽  
Iκb Kinase ◽  
Biochemical Journal ◽  
Upstream Kinase

IKKβ (IκB kinase β) is a core component of signalling pathways that control the activation of NF-κB (nuclear factor κB) transcription factors, which regulate many physiological processes, including cell survival, immunity and DNA-damage responses. Like many kinases, activation of IKKβ requires phosphorylation of the activation loop of its kinase domain. Different upstream protein kinases, and IKKβ itself, have been reported to directly phosphorylate and activate IKKβ in vitro, but the exact molecular mechanism of IKKβ activation in cells has remained unclear. In a recent article in the Biochemical Journal, Zhang and co-workers showed that IKKβ is activated by two sequential phosphorylations of its activation loop in response to TNF (tumour necrosis factor), IL-1 (interleukin-1) and TLR (Toll-like receptor) ligands. Using a combination of biochemical and genetic approaches, they demonstrate that IKKβ is first phosphorylated by the upstream kinase TAK1 [TGFβ (transforming growth factor β)-activated kinase-1] at Ser177, which then serves as a priming signal for subsequent IKKβ autophosphorylation at Ser181. This study resolves two apparently conflicting earlier models of IKKβ activation into a single unified model, and suggests that the IKKβ activation loop may integrate distinct ‘upsteam’ signals to activate NF-κB.

scholarly journals TAK1 Is Essential for Osteoclast Differentiation and Is an Important Modulator of Cell Death by Apoptosis and Necroptosis

2012 ◽  
Vol 33 (3) ◽  
pp. 582-595 ◽  
Author(s):  
Betty Lamothe ◽  
YunJu Lai ◽  
Min Xie ◽  
Michael D. Schneider ◽  
Bryant G. Darnay
Keyword(s):  
Cell Death ◽  
Transforming Growth Factor ◽  
Interleukin 1 ◽  
Osteoclast Differentiation ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Interacting Protein ◽  
Iκb Kinase ◽  
Mitogen Activated Protein ◽  
Macrophage Colony

ABSTRACTTransforming growth factor β (TGF-β)-activated kinase 1 (TAK1), a mitogen-activated protein 3 (MAP3) kinase, plays an essential role in inflammation by activating the IκB kinase (IKK)/nuclear factor κB (NF-κB) and stress kinase (p38 and c-Jun N-terminal kinase [JNK]) pathways in response to many stimuli. The tumor necrosis factor (TNF) superfamily member receptor activator of NF-κB ligand (RANKL) regulates osteoclastogenesis through its receptor, RANK, and the signaling adaptor TRAF6. Because TAK1 activation is mediated through TRAF6 in the interleukin 1 receptor (IL-1R) and toll-like receptor (TLR) pathways, we sought to investigate the consequence of TAK1 deletion in RANKL-mediated osteoclastogenesis. We generated macrophage colony-stimulating factor (M-CSF)-derived monocytes from the bone marrow of mice with TAK1 deletion in the myeloid lineage. Unexpectedly, TAK1-deficient monocytes in culture died rapidly but could be rescued by retroviral expression of TAK1, inhibition of receptor-interacting protein 1 (RIP1) kinase activity with necrostatin-1, or simultaneous genetic deletion of TNF receptor 1 (TNFR1). Further investigation using TAK1-deficient mouse embryonic fibroblasts revealed that TNF-α-induced cell death was abrogated by the simultaneous inhibition of caspases and knockdown of RIP3, suggesting that TAK1 is an important modulator of both apoptosis and necroptosis. Moreover, TAK1-deficient monocytes rescued from programmed cell death did not form mature osteoclasts in response to RANKL, indicating that TAK1 is indispensable to RANKL-induced osteoclastogenesis. To our knowledge, we are the first to report that mice in which TAK1 has been conditionally deleted in osteoclasts develop osteopetrosis.

A mechanism for the suppression of interleukin-1-induced nuclear factor κB activation by protein phosphatase 2Cη-2

2009 ◽  
Vol 423 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Takeaki Henmi ◽  
Kazutaka Amano ◽  
Yuko Nagaura ◽  
Kunihiro Matsumoto ◽  
Seishi Echigo ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Interleukin 1 ◽  
Ectopic Expression ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Signalling Pathway ◽  
Nuclear Factor ◽  
Interfering Rna ◽  
Signalling Cascade

IL-1 (interleukin-1) is a pro-inflammatory cytokine that has a variety of effects during the process of inflammation. Stimulating cells with IL-1 initiates a signalling cascade that includes the activation of NF-κB (nuclear factor κB), and subsequently induces a variety of inflammatory genes. Although the molecular mechanism for the IL-1-induced activation of NF-κB has been well documented, much less is known about the mechanism by which protein phosphatases down-regulate this pathway. Here we show that mouse PP2Cη-2 (protein serine/threonine phosphatase 2Cη-2), a novel member of the protein serine/threonine phosphatase 2C family, inhibits the IL-1–NF-κB signalling pathway. Ectopic expression of PP2Cη-2 in human embryonic kidney HEK293IL-1RI cells inhibited the IL-1-induced activation of NF-κB. TAK1 (transforming-growth-factor-β-activated kinase 1) mediates the IL-1 signalling pathway to NF-κB, and we observed that the TAK1-induced activation of NF-κB was suppressed by PP2Cη-2 expression. Expression of IKKβ [IκB (inhibitory κB) kinase β], which lies downstream of TAK1, activates NF-κB, and this activation was also readily reversed by PP2Cη-2 co-expression. Additionally, PP2Cη-2 knockdown with small interfering RNA further stimulated the IL-1-enhanced phosphorylation of IKKβ and destabilization of IκBα in HeLa cells. PP2Cη-2 knockdown also increased the IL-1-induced expression of IL-6 mRNA. Furthermore, IKKβ was readily dephosphorylated by PP2Cη-2 in vitro. These results suggest that PP2Cη-2 inhibits the IL-1–NF-κB signalling pathway by selectively dephosphorylating IKKβ.

scholarly journals TAB1 regulates glycolysis and activation of macrophages in diabetic nephropathy

2020 ◽  
Vol 69 (12) ◽  
pp. 1215-1234
Author(s):  
Hanxu Zeng ◽  
Xiangming Qi ◽  
Xingxin Xu ◽  
Yonggui Wu
Keyword(s):  
Diabetic Nephropathy ◽  
Transforming Growth Factor ◽  
Lentiviral Vector ◽  
Hypoxia Inducible Factor ◽  
Damage Index ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Inflammatory Factors

Abstract Objective and design Macrophages exhibit strong phenotypic plasticity and can mediate renal inflammation by polarizing into an M1 phenotype. They play a pivotal role in diabetic nephropathy (DN). Here, we have investigated the regulatory role of transforming growth factor β-activated kinase 1-binding protein 1 (TAB1) in glycolysis and activation of macrophages during DN. Methods TAB1 was inhibited using siRNA in high glucose (HG)-stimulated bone marrow-derived macrophages (BMMs) and lentiviral vector-mediated TAB1 knockdown was used in streptozotocin (STZ)-induced diabetic mice. Western blotting, flow cytometry, qRT-PCR, ELISA, PAS staining and immunohistochemical staining were used for assessment of TAB1/nuclear factor-κB (NF-κB)/hypoxia-inducible factor-1α (HIF-1α), iNOS, glycolysis, inflammation and the clinical and pathological manifestations of diabetic nephropathy. Results We found that TAB1/NF-κB/HIF-1α, iNOS and glycolysis were up-regulated in BMMs under HG conditions, leading to release of further inflammatory factors, Downregulation of TAB1 could inhibit glycolysis/polarization of macrophages and inflammation in vivo and in vitro. Furthermore, albuminuria, the tubulointerstitial damage index and glomerular mesangial expansion index of STZ-induced diabetic nephropathy mice were decreased by TAB1 knockdown. Conclusions Our results suggest that the TAB1/NF-κB/HIF-1α signaling pathway regulates glycolysis and activation of macrophages in DN.

scholarly journals Distinct Mutations in IRAK-4 Confer Hyporesponsiveness to Lipopolysaccharide and Interleukin-1 in a Patient with Recurrent Bacterial Infections

2003 ◽  
Vol 198 (4) ◽  
pp. 521-531 ◽  
Author(s):  
Andrei E. Medvedev ◽  
Arnd Lentschat ◽  
Douglas B. Kuhns ◽  
Jorge C.G. Blanco ◽  
Cindy Salkowski ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Interleukin 1 ◽  
Nuclear Factor Κb ◽  
Kinase Domain ◽  
Compound Heterozygous ◽  
Activator Protein 1 ◽  
Death Domain ◽  
Aseptic Inflammation

We identified previously a patient with recurrent bacterial infections who failed to respond to gram-negative LPS in vivo, and whose leukocytes were profoundly hyporesponsive to LPS and IL-1 in vitro. We now demonstrate that this patient also exhibits deficient responses in a skin blister model of aseptic inflammation. A lack of IL-18 responsiveness, coupled with diminished LPS and/or IL-1–induced nuclear factor–κB and activator protein-1 translocation, p38 phosphorylation, gene expression, and dysregulated IL-1R–associated kinase (IRAK)–1 activity in vitro support the hypothesis that the defect lies within the signaling pathway common to toll-like receptor 4, IL-1R, and IL-18R. This patient expresses a “compound heterozygous” genotype, with a point mutation (C877T in cDNA) and a two-nucleotide, AC deletion (620–621del in cDNA) encoded by distinct alleles of the IRAK-4 gene (GenBank/EMBL/DDBJ accession nos. AF445802 and AY186092). Both mutations encode proteins with an intact death domain, but a truncated kinase domain, thereby precluding expression of full-length IRAK-4 (i.e., a recessive phenotype). When overexpressed in HEK293T cells, neither truncated form augmented endogenous IRAK-1 kinase activity, and both inhibited endogenous IRAK-1 activity modestly. Thus, IRAK-4 is pivotal in the development of a normal inflammatory response initiated by bacterial or nonbacterial insults.

scholarly journals The IKKβ Subunit of IκB Kinase (IKK) is Essential for Nuclear Factor κB Activation and Prevention of Apoptosis

1999 ◽  
Vol 189 (11) ◽  
pp. 1839-1845 ◽  
Author(s):  
Zhi-Wei Li ◽  
Wenming Chu ◽  
Yinling Hu ◽  
Mireille Delhase ◽  
Tom Deerinck ◽  
...  
Keyword(s):  
Interleukin 1 ◽  
Nuclear Factor Κb ◽  
Regulatory Subunit ◽  
Nuclear Factor ◽  
Catalytic Subunits ◽  
Iκb Kinase ◽  
Ikk Complex ◽  
Factor Α ◽  
Necrosis Factor

The IκB kinase (IKK) complex is composed of three subunits, IKKα, IKKβ, and IKKγ (NEMO). While IKKα and IKKβ are highly similar catalytic subunits, both capable of IκB phosphorylation in vitro, IKKγ is a regulatory subunit. Previous biochemical and genetic analyses have indicated that despite their similar structures and in vitro kinase activities, IKKα and IKKβ have distinct functions. Surprisingly, disruption of the Ikkα locus did not abolish activation of IKK by proinflammatory stimuli and resulted in only a small decrease in nuclear factor (NF)-κB activation. Now we describe the pathophysiological consequence of disruption of the Ikkβ locus. IKKβ-deficient mice die at mid-gestation from uncontrolled liver apoptosis, a phenotype that is remarkably similar to that of mice deficient in both the RelA (p65) and NF-κB1 (p50/p105) subunits of NF-κB. Accordingly, IKKβ-deficient cells are defective in activation of IKK and NF-κB in response to either tumor necrosis factor α or interleukin 1. Thus IKKβ, but not IKKα, plays the major role in IKK activation and induction of NF-κB activity. In the absence of IKKβ, IKKα is unresponsive to IKK activators.

Modelling the dynamics of signalling pathways

2008 ◽  
Vol 45 ◽  
pp. 1-28 ◽  
Author(s):  
Sree N. Sreenath ◽  
Kwang-Hyun Cho ◽  
Peter Wellstead
Keyword(s):  
Chemical Kinetics ◽  
Transforming Growth Factor ◽  
Interleukin 1 ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Stochastic Chemical Kinetics ◽  
Discrete State ◽  
Explicit Mention ◽  
Decision Making Processes ◽  
The Right

In the present chapter we discuss methodologies for the modelling, calibration and validation of cellular signalling pathway dynamics. The discussion begins with the typical range of techniques for modelling that might be employed to go from the chemical kinetics to a mathematical model of biochemical pathways. In particular, we consider the decision-making processes involved in selecting the right mechanism and level of detail of representation of the biochemical interactions. These include the choice between (i) deterministic and stochastic chemical kinetics representations, (ii) discrete and continuous time models and (iii) representing continuous and discrete state processes. We then discuss the task of calibrating the models using information available in web-based databases. For situations in which the data are not available from existing sources we discuss model calibration based upon measured data and system identification methods. Such methods, together with mathematical modelling databases and computational tools, are often available in standard packages. We therefore make explicit mention of a range of popular and useful sites. As an example of the whole modelling and calibration process, we discuss a study of the cross-talk between the IL-1 (interleukin-1)-stimulated NF-κB (nuclear factor κB) pathway and the TGF-β (transforming growth factor β)-stimulated Smad2 pathway.

scholarly journals IκB Kinase γ/Nuclear Factor-κB-Essential Modulator (IKKγ/NEMO) Facilitates RhoA GTPase Activation, which, in Turn, Activates Rho-associated Kinase (ROCK) to Phosphorylate IKKβ in Response to Transforming Growth Factor (TGF)-β1

2013 ◽  
Vol 289 (3) ◽  
pp. 1429-1440 ◽  
Author(s):  
Hee-Jun Kim ◽  
Jae-Gyu Kim ◽  
Mi-Young Moon ◽  
Seol-Hye Park ◽  
Jae-Bong Park
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Nuclear Factor Κb ◽  
Exchange Factor ◽  
Rhoa Activation ◽  
Gtp Binding ◽  
Iκb Kinase ◽  
Gtpase Activation ◽  
Tgf Β1

Transforming growth factor (TGF)-β1 plays several roles in a variety of cellular functions. TGF-β1 transmits its signal through Smad transcription factor-dependent and -independent pathways. It was reported that TGF-β1 activates NF-κB and RhoA, and RhoA activates NF-κB in several kinds of cells in a Smad-independent pathway. However, the activation molecular mechanism of NF-κB by RhoA upon TGF-β1 has not been clearly elucidated. We observed that RhoA-GTP level was increased by TGF-β1 in RAW264.7 cells. RhoA-GDP and RhoGDI were bound to N- and C-terminal domains of IKKγ, respectively. Purified IKKγ facilitated GTP binding to RhoA complexed with RhoGDI. Furthermore, Dbs, a guanine nucletotide exchange factor of RhoA much more enhanced GTP binding to RhoA complexed with RhoGDI in the presence of IKKγ. Indeed, si-IKKγ abolished RhoA activation in response to TGF-β1 in cells. However, TGF-β1 stimulated the release of RhoA-GTP from IKKγ and Rho-associated kinase (ROCK), an active RhoA effector protein, directly phosphorylated IKKβ in vitro, whereas TGF-β1-activated kinase 1 activated RhoA upon TGF-β1 stimulation. Taken together, our data indicate that IKKγ facilitates RhoA activation via a guanine nucletotide exchange factor, which in turn activates ROCK to phosphorylate IKKβ, leading to NF-κB activation that induced the chemokine expression and cell migration upon TGF-β1.

USP4 deficiency exacerbates hepatic ischaemia/reperfusion injury via TAK1 signalling

2019 ◽  
Vol 133 (2) ◽  
pp. 335-349 ◽  
Author(s):  
Jiangqiao Zhou ◽  
Tao Qiu ◽  
Tianyu Wang ◽  
Zhongbao Chen ◽  
Xiaoxiong Ma ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Transforming Growth Factor ◽  
Gene Knockout ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Pathological Process ◽  
Signalling Pathways ◽  
Ischaemia Reperfusion Injury ◽  
Ischaemia Reperfusion

Abstract Ubiquitin-specific peptidase 4 (USP4) protein is a type of deubiquitination enzyme that is correlated with many important biological processes. However, the function of USP4 in hepatic ischaemia/reperfusion (I/R) injury remains unknown. The aim of the present study was to explore the role of USP4 in hepatic I/R injury. USP4 gene knockout mice and primary hepatocytes were used to construct hepatic I/R models. The effect of USP4 on hepatic I/R injury was examined via pathological and molecular analyses. Our results indicated that USP4 was significantly up-regulated in liver of mice subjected to hepatic I/R injury. USP4 knockout mice exhibited exacerbated hepatic I/R injury, as evidenced by enhanced liver inflammation via the nuclear factor κB (NF-κB) signalling pathway and increased hepatocyte apoptosis. Additionally, USP4 overexpression inhibited hepatocyte inflammation and apoptosis on hepatic I/R stimulation. Mechanistically, our study demonstrates that USP4 deficiency exerts its detrimental effects on hepatic I/R injury by inducing activation of the transforming growth factor β-activated kinase 1 (TAK1)/JNK signalling pathways. TAK1 was required for USP4 function in hepatic I/R injury as TAK1 inhibition abolished USP4 function in vitro. In conclusion, our study demonstrates that USP4 deficiency plays a detrimental role in hepatic I/R injury by promoting activation of the TAK1/JNK signalling pathways. Modulation of this axis may be a novel strategy to alleviate the pathological process of hepatic I/R injury.

Abstract 32: Investigating the Autoactivation of p38α Mitogen-Activated Protein Kinase Mediated by Transforming Growth Factor-β-Activated Protein Kinase Binding Protein 1

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Gian Felice De Nicola ◽  
E D Martin ◽  
Rekha Bassi ◽  
Sharwari Verma ◽  
Maria Conte ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Transforming Growth Factor ◽  
Binding Protein ◽  
Transforming Growth Factor Β ◽  
Mitogen Activated Protein Kinase ◽  
Scaffolding Protein ◽  
Titration Calorimetry ◽  
Activation Loop

Activation of p38α MAPK (p38α), by phosphorylation of two residues in the TGY motif of the activation loop, can occur independently of upstream kinases. One such mechanism involves the scaffolding protein Transforming Growth Factor-β-activated protein kinase binding protein 1 (TAB1). Under certain circumstances, such as myocardial ischemia, this activation can aggravate lethal injury. It is one of a few examples of activating autophosphorylation and poses a conundrum. How does an inactive kinase, and therefore with low affinity for ATP, phosphorylate its own activation loop when ATP binding is a prerequisite step for phosphotransfer? The aim of this study was to characterize the TAB1 binding of p38α. The binding characteristics of p38α and TAB1 were determined by Isothermal Titration Calorimetry, followed by the binding of p38α and ATPγS, a slowly hydrolysable form of ATP, in the presence and absence of TAB1. The binding of TAB1 to p38α increased significantly the affinity of p38α for ATP. Following the identification of a key region in TAB1 responsible for p38α binding, a synthetic peptide encompassing this region was used to analyze the biophysical and biological consequences of TAB1 binding. In vitro kinase assays were used to test the biochemical characteristics using a combination of wildtype kinase, kinase dead (K53M) or both in the absence or presence of TAB1(371-416). Using an antibody specific to the dual phosphorylation of the TGY motif as a readout, TAB1 binding to p38α increased p38α autophosphorylation in cis . NMR was employed to map the interaction surfaces between of p38α and TAB1 and to analyze the effect of TAB1-binding on p38α. The residues identified as important for the interaction between TAB1 and p38α were mutated and tested in cell free and biological systems to confirm their role as critical determinants for binding. In conclusion, we have further elucidated a mechanism whereby TAB1 binding to p38α alters the conformation of p38α, increasing its affinity for ATP and thereby facilitating autophosphorylation. We have identified the binding contacts of TAB1 and p38α that may be important in the design of therapeutics enabling selective and circumstance-specific inhibition of p38α activation.

Sign in / Sign up

Export Citation Format

Share Document