Cezanne (<scp>OTUD</scp>7B) regulates <scp>HIF</scp>‐1α homeostasis in a proteasome‐independent manner

Bremm, Anja; Moniz, Sónia; Mader, Julia K.; Rocha, Sónia; Komander, David

doi:10.15252/embr.201438850

Cited by 79 publications

(90 citation statements)

References 47 publications

(59 reference statements)

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“…Flag-Myc-OTUB1, Flag-Myc-OTUB2, Flag-Myc-OTUD3, Flag-Myc-OTUD4, Flag-Myc-OTUD5, Flag-Myc-OTUD6A, Flag-Myc-OTUD6B, Flag-Myc-OTUD7A and Flag-Myc-OTUD7B constructs have been described previously 31 . The HA-GβL(K305R), HA-GβL (K313R), HA-GβL(K305R/K313R) (KRKR), HA-GβL(P265A/E267A) (PEAA), Flag-Myc-OTUD7B(C194A) mutants 29,32 were constructed using the Site-Directed Mutagenesis Kit (Stratagene) following the manufacturer’s instructions. His-Ub, His-Ub(K6R), His-Ub(K11R), His-Ub(K27R), His-Ub(K29R), His-Ub(K33R), His-Ub(K48R), His-Ub(K63R), His-Ub(K0), His-Ub(K48) only and His-Ub(K63) only vectors were provided by P. P. Pandolfi (Beth Israel Deaconess Medical Center, Harvard Medical School).…”

Section: Methodsmentioning

confidence: 99%

TRAF2 and OTUD7B govern a ubiquitin-dependent switch that regulates mTORC2 signalling

Wang

Jie

Joo

et al. 2017

Nature

150

181

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The mechanistic target of rapamycin (mTOR) has a key role in the integration of various physiological stimuli to regulate several cell growth and metabolic pathways1. mTOR primarily functions as a catalytic subunit in two structurally related but functionally distinct multi-component kinase complexes, mTOR complex 1 (mTORCl) and mTORC2 (refs 1, 2). Dysregulation of mTOR signalling is associated with a variety of human diseases, including metabolic disorders and cancer1. Thus, both mTORCl and mTORC2 kinase activity is tightly controlled in cells. mTORCl is activated by both nutrients3–6 and growth factors7, whereas mTORC2 responds primarily to extracellular cues such as growth-factor-triggered activation of PI3K signalling8–10. Although both mTOR and GβL (also known as MLST8) assemble into mTORC1 and mTORC2 (refs 11–15), it remains largely unclear what drives the dynamic assembly of these two functionally distinct complexes. Here we show, in humans and mice, that the K63-linked polyubiquitination status of GβL dictates the homeostasis of mTORC2 formation and activation. Mechanistically, the TRAF2 E3 ubiquitin ligase promotes K63-linked polyubiquitination of GβL, which disrupts its interaction with the unique mTORC2 component SIN1 (refs 12–14) to favour mTORC1 formation. By contrast, the OTUD7B deubiquitinase removes polyubiquitin chains from GβL to promote GβL interaction with SIN1, facilitating mTORC2 formation in response to various growth signals. Moreover, loss of critical ubiquitination residues in GβL, by either K305R/K313R mutations or a melanoma-associated GβL(ΔW297) truncation, leads to elevated mTORC2 formation, which facilitates tumorigenesis, in part by activating AKT oncogenic signalling. In support of a physiologically pivotal role for OTUD7B in the activation of mTORC2/AKT signalling, genetic deletion of Otud7b in mice suppresses Akt activation and Kras-driven lung tumorigenesis in vivo. Collectively, our study reveals a GβL-ubiquitination-dependent switch that fine-tunes the dynamic organization and activation of the mTORC2 kinase under both physiological and pathological conditions.

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Section: Methodsmentioning

confidence: 99%

TRAF2 and OTUD7B govern a ubiquitin-dependent switch that regulates mTORC2 signalling

Wang

Jie

Joo

et al. 2017

Nature

150

181

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“…It has been shown that the K11-linkage-specific DUB Cezanne (OTUD7B) (Bremm et al, 2010;Mevissen et al, 2013) regulates stability of the transcription factor HIF-1α (Bremm et al, 2014) and expression levels of HIF-2α (Moniz et al, 2015). However, in this context, the exact topology of the ubiquitin signal is not yet understood.…”

Section: K11 Linkages In Heterotypic Ubiquitin Conjugates -A Powerfulmentioning

confidence: 99%

Ubiquitin chain diversity at a glance

Akutsu

Đikić

Bremm

2016

Journal of Cell Science

Self Cite

422

367

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Ubiquitin plays an essential role in modulating protein functions, and deregulation of the ubiquitin system leads to the development of multiple human diseases. Owing to its molecular features, ubiquitin can form various homo-and heterotypic polymers on substrate proteins, thereby provoking distinct cellular responses. The concept of multifaceted ubiquitin chains encoding different functions has been substantiated in recent years. It has been established that all possible ubiquitin linkage types are utilized for chain assembly and propagation of specific signals in vivo. In addition, branched ubiquitin chains and phosphorylated ubiquitin molecules have been put under the spotlight recently. The development of novel technologies has provided detailed insights into the structure and function of previously poorly understood ubiquitin signals. In this Cell Science at a Glance article and accompanying poster, we provide an update on the complexity of ubiquitin chains and their physiological relevance.

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“…5 However, in some situations, this process can be reversed by Cezanne-a deubiquitinating cysteine protease that can remove polyubiquitin chains from HIF1α and other proteins. 6 Our study revealed that Cezanne was induced by disturbed flow, and loss-of-function approaches (siRNA, dominant-negative) revealed that it is essential for HIF1α protein expression under these conditions. Cezanne reduced the abundance of high molecular weight forms of HIF1α and coprecipitating polyubiquitin under conditions of disturbed flow suggesting that it stabilizes HIF1α via deubiquitination.…”

mentioning

confidence: 67%

Response by Feng et al to Letter Regarding Article, “Mechanical Activation of Hypoxia-Inducible Factor 1α Drives Endothelial Dysfunction at Atheroprone Sites”

Feng

Fragiadaki

Souilhol

et al. 2017

ATVB

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In Response:We welcome the letter from Wu et al on our recent study, which showed that disturbed flow can activate hypoxia-inducible factor (HIF1α) leading to enhanced endothelial glycolysis, proliferation, and vascular inflammation 1 . It is notable that Wu et al 2 independently recapitulated our observation in a series of elegant experiments. In both studies, unbiased transcriptome-based methods identified enriched expression of HIF1α, and its target genes, in endothelial cells exposed to disturbed flow. 1,2 It was also demonstrated, by both studies, that HIF1α-dependent glycolysis promotes vascular inflammation at atheroprone sites via induction of adhesion molecules and other inflammatory mediators. In contrast to Wu et al, 2 our study revealed that HIF1α additionally induces excessive rates of endothelial cell proliferation 1 -a phenotype that has been previously linked with vascular leakiness and atherogenesis. Taken together, the effects of HIF1α on inflammation and proliferation represent a plausible dual mechanism to explain its previously described proatherogenic effects. 3 We performed detailed biochemical studies to define the underlying molecular mechanism for HIF1α stabilization in the presence of oxygen in endothelial cells exposed to disturbed flow; dual regulation of HIF1α at both transcriptional and protein levels was identified. Evidence from multiple experiments led us to conclude that transcriptional upregulation of HIF1α mRNA in response to disturbed flow is under the control of NF-κB because (1) HIF1α expression was significantly reduced by overexpression of IκBα (an inhibitor of NF-κB), (2) silencing of RelA NF-κB subunits using siRNA reduced HIF1α expression, and (3) chromatin immunoprecipitation revealed that NF-κB interacts directly with HIF1α promoter sequences. Moreover, our results are in agreement with previous studies demonstrating that NF-κB can induce HIF1α in other contexts. 4 Wu et al 2 questioned our observation because they found that a peptide inhibitor of NF-κB did not alter HIF1α expression; however, we are uncertain of their conclusion because it seems to be based on data from a single Western blot that was not quantified. On the contrary, Wu et al 2 show convincingly that HIF1α can activate NF-κB in endothelium exposed to disturbed flow. Considering the data from both studies, we posit that NF-κB is positioned both upstream and downstream from HIF1α in cells exposed to disturbed flow, thereby forming a positive feedback loop in HIF1α activation.HIF1α is tightly regulated by enzymes that control the attachment of Lys48-linked polyubiquitin chains-a modification that targets proteins for degradation. In the presence of oxygen, HIF1α is modified with hydroxyl groups by prolyl hydroxylase domain (PHD) enzymes, and this modification is subsequently recognized by von Hippel-Lindau E3 ubiquitin ligase, which targets HIF1α for Lys48 polyubiquitination.5 However, in some situations, this process can be reversed by Cezanne-a deubiquitinating cysteine protease that can remove poly...

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Cezanne (OTUD7B) regulates HIF‐1α homeostasis in a proteasome‐independent manner

Cited by 79 publications

References 47 publications

TRAF2 and OTUD7B govern a ubiquitin-dependent switch that regulates mTORC2 signalling

TRAF2 and OTUD7B govern a ubiquitin-dependent switch that regulates mTORC2 signalling

Ubiquitin chain diversity at a glance

Response by Feng et al to Letter Regarding Article, “Mechanical Activation of Hypoxia-Inducible Factor 1α Drives Endothelial Dysfunction at Atheroprone Sites”

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