scholarly journals p97 Negatively Regulates NRF2 by Extracting Ubiquitylated NRF2 from the KEAP1-CUL3 E3 Complex

2017 ◽  
Vol 37 (8) ◽  
Author(s):  
Shasha Tao ◽  
Pengfei Liu ◽  
Gang Luo ◽  
Montserrat Rojo de la Vega ◽  
Heping Chen ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Protein Complexes ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Proteasomal Degradation ◽  
Ubiquitin Ligase Complex ◽  
Ubiquitin Proteasome ◽  
Client Proteins

ABSTRACT Activation of the stress-responsive transcription factor NRF2 is the major line of defense to combat oxidative or electrophilic insults. Under basal conditions, NRF2 is continuously ubiquitylated by the KEAP1-CUL3-RBX1 E3 ubiquitin ligase complex and is targeted to the proteasome for degradation (the canonical mechanism). However, the path from the CUL3 complex to ultimate proteasomal degradation was previously unknown. p97 is a ubiquitin-targeted ATP-dependent segregase that extracts ubiquitylated client proteins from membranes, protein complexes, or chromatin and has an essential role in autophagy and the ubiquitin proteasome system (UPS). In this study, we show that p97 negatively regulates NRF2 through the canonical pathway by extracting ubiquitylated NRF2 from the KEAP1-CUL3 E3 complex, with the aid of the heterodimeric cofactor UFD1/NPL4 and the UBA-UBX-containing protein UBXN7, for efficient proteasomal degradation. Given the role of NRF2 in chemoresistance and the surging interest in p97 inhibitors to treat cancers, our results indicate that dual p97/NRF2 inhibitors may offer a more potent and long-term avenue of p97-targeted treatment.

Gfi1 ubiquitination and proteasomal degradation is inhibited by the ubiquitin ligase Triad1

Blood ◽  
2007 ◽  
Vol 110 (9) ◽  
pp. 3128-3135 ◽  
Author(s):  
Jurgen A. F. Marteijn ◽  
Laurens T. van der Meer ◽  
Liesbeth van Emst ◽  
Simon van Reijmersdal ◽  
Willemijn Wissink ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Proteasomal Degradation ◽  
Binding Domain ◽  
U937 Cells ◽  
Dna Binding Domain ◽  
Protein Levels ◽  
Ubiquitin Ligase Activity ◽  
Ubiquitin Proteasome

Abstract Growth factor independence 1 (Gfi1) is a transcriptional repressor essential for the function and development of many different hematopoietic lineages. The Gfi1 protein expression is regulated by the ubiquitin-proteasome system. In granulocytes, Gfi1 is rapidly degraded by the proteasome, while it is more stable in monocytes. How the ubiquitination and degradation of Gfi1 is regulated is unclear. Here, we show that the ubiquitin ligase Triad1 interacts with the DNA-binding domain of Gfi1. Unexpectedly, we found that Triad1 inhibited Gfi1 ubiquitination, resulting in a prolonged half-life. Down-regulation of endogenous Triad1 by siRNAs resulted in increased Gfi1 ubiquitination. In U937 cells, Triad1 caused an increase in endogenous Gfi1 protein levels and slowed cell proliferation in a similar manner when Gfi1 itself was expressed. A Triad1 mutant that lacks the Gfi1-binding domain did not affect Gfi1 levels and proliferation. Because neither proteasome-ubiquitin nor Triad1 ubiquitin ligase activity was required for the inhibition of Gfi1 ubiquitination, these data suggest that Triad1 competes for Gfi1 binding with as yet to be identified E3 ubiquitin ligases that do mark Gfi1 for proteasomal degradation. The finetuning of Gfi1 protein levels regulated by Triad1 defines an unexpected role for this protein in hematopoiesis.

scholarly journals The E3 ubiquitin ligase UBR5 regulates centriolar satellite stability and primary cilia

2018 ◽  
Vol 29 (13) ◽  
pp. 1542-1554 ◽  
Author(s):  
Robert F. Shearer ◽  
Kari-Anne Myrum Frikstad ◽  
Jessie McKenna ◽  
Rachael A. McCloy ◽  
Niantao Deng ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Developmental Disorders ◽  
Primary Cilia ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Interacting Protein ◽  
Robust Model ◽  
Cilia Formation ◽  
Cytoplasmic Organization ◽  
Ubiquitin Proteasome

Primary cilia are crucial for signal transduction in a variety of pathways, including hedgehog and Wnt. Disruption of primary cilia formation (ciliogenesis) is linked to numerous developmental disorders (known as ciliopathies) and diseases, including cancer. The ubiquitin–proteasome system (UPS) component UBR5 was previously identified as a putative positive regulator of ciliogenesis in a functional genomics screen. UBR5 is an E3 ubiquitin ligase that is frequently deregulated in tumors, but its biological role in cancer is largely uncharacterized, partly due to a lack of understanding of interacting proteins and pathways. We validated the effect of UBR5 depletion on primary cilia formation using a robust model of ciliogenesis, and identified CSPP1, a centrosomal and ciliary protein required for cilia formation, as a UBR5-interacting protein. We show that UBR5 ubiquitylates CSPP1, and that UBR5 is required for cytoplasmic organization of CSPP1-comprising centriolar satellites in centrosomal periphery, suggesting that UBR5-mediated ubiquitylation of CSPP1 or associated centriolar satellite constituents is one underlying requirement for cilia expression. Hence, we have established a key role for UBR5 in ciliogenesis that may have important implications in understanding cancer pathophysiology.

scholarly journals Altered ubiquitin-proteasome signaling in right ventricular hypertrophy and failure

2013 ◽  
Vol 305 (4) ◽  
pp. H551-H562 ◽  
Author(s):  
Viswanathan Rajagopalan ◽  
Mingming Zhao ◽  
Sushma Reddy ◽  
Giovanni Fajardo ◽  
Xuejun Wang ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Ubiquitin Ligase ◽  
Ventricular Hypertrophy ◽  
Ubiquitin Proteasome System ◽  
Left Ventricular ◽  
Percent Increase ◽  
Ubiquitin Proteasome ◽  
Pulmonary Artery Constriction ◽  
Heart Lesions

Alterations in the ubiquitin-proteasome system (UPS) have been described in left ventricular hypertrophy and failure, although results have been inconsistent. The role of the UPS in right ventricular (RV) hypertrophy (RVH) and RV failure (RVF) is unknown. Given the greater percent increase in RV mass associated with RV afterload stress, as present in many congenital heart lesions, we hypothesized that alterations in the UPS could play an important role in RVH/RVF. UPS expression and activity were measured in the RV from mice with RVH/RVF secondary to pulmonary artery constriction (PAC). Epoxomicin and MG132 were used to inhibit the proteasome, and overexpression of the 11S PA28α subunit was used to activate the proteasome. PAC mice developed RVH (109.3% increase in RV weight to body weight), RV dilation with septal shift, RV dysfunction, and clinical RVF. Proteasomal function (26S β5 chymotrypsin-like activity) was decreased 26% ( P < 0.05). Protein expression of 19S subunit Rpt5 ( P < 0.05), UCHL1 deubiquitinase ( P < 0.0001), and Smurf1 E3 ubiquitin ligase ( P < 0.01) were increased, as were polyubiquitinated proteins ( P < 0.05) and free-ubiquitins ( P = 0.05). Pro-apoptotic Bax was increased ( P < 0.0001), whereas anti-apoptotic Bcl-2 decreased ( P < 0.05), resulting in a sixfold increase in the Bax/Bcl-2 ratio. Proteasomal inhibition did not accelerate RVF. However, proteasome enhancement by cardiac-specific proteasome overexpression partially improved survival. Proteasome activity is decreased in RVH/RVF, associated with upregulation of key UPS regulators and pro-apoptotic signaling. Enhancement of proteasome function partially attenuates RVF, suggesting that UPS dysfunction contributes to RVF.

scholarly journals ZSCAN4 is negatively regulated by the ubiquitin-proteasome system and the E3 ubiquitin ligase RNF20

2018 ◽  
Vol 498 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Benjamin A. Portney ◽  
Raju Khatri ◽  
W. Alex Meltzer ◽  
Jennifer M. Mariano ◽  
Michal Zalzman
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Ubiquitin Proteasome

scholarly journals Defining the Interactions and Role of DCAF1/VPRBP in the DDB1-Cullin4A E3 Ubiquitin Ligase Complex Engaged by HIV-1 Vpr to Induce a G2 Cell Cycle Arrest

PLoS ONE ◽  
2014 ◽  
Vol 9 (2) ◽  
pp. e89195 ◽  
Author(s):  
Francine C. A. Gérard ◽  
Ruifeng Yang ◽  
Bizhan Romani ◽  
Alexis Poisson ◽  
Jean-Philippe Belzile ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Cycle Arrest ◽  
Ubiquitin Ligase Complex ◽  
G2 Cell Cycle Arrest ◽  
Hiv 1

scholarly journals E3 ubiquitin ligase HECTD2 mediates melanoma progression and immune evasion

Oncogene ◽  
2021 ◽  
Author(s):  
Eleonora Ottina ◽  
Veera Panova ◽  
Laura Doglio ◽  
Anastasiya Kazachenka ◽  
Georgina Cornish ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cancer Cell ◽  
Ubiquitin Ligase ◽  
Immune Evasion ◽  
Tumour Progression ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Tumour Immunity ◽  
Murine Melanoma

AbstractThe ubiquitin-proteasome system maintains protein homoeostasis, underpins the cell cycle, and is dysregulated in cancer. However, the role of individual E3 ubiquitin ligases, which mediate the final step in ubiquitin-mediated proteolysis, remains incompletely understood. Identified through screening for cancer-specific endogenous retroviral transcripts, we show that the little-studied E3 ubiquitin ligase HECTD2 exerts dominant control of tumour progression in melanoma. HECTD2 cell autonomously drives the proliferation of human and murine melanoma cells by accelerating the cell cycle. HECTD2 additionally regulates cancer cell production of immune mediators, initiating multiple immune suppressive pathways, which include the cyclooxygenase 2 (COX2) pathway. Accordingly, higher HECTD2 expression is associated with weaker anti-tumour immunity and unfavourable outcome of PD-1 blockade in human melanoma and counteracts immunity against a model tumour antigen in murine melanoma. This central, multifaceted role of HECTD2 in cancer cell-autonomous proliferation and in immune evasion may provide a single target for a multipronged therapy of melanoma.

scholarly journals Diabetic cardiomyopathy: role of the E3 ubiquitin ligase

2016 ◽  
Vol 310 (7) ◽  
pp. E473-E483 ◽  
Author(s):  
Tao Bai ◽  
Fan Wang ◽  
Nicholas Mellen ◽  
Yang Zheng ◽  
Lu Cai
Keyword(s):  
Insulin Receptor ◽  
Ubiquitin Ligase ◽  
Diabetic Cardiomyopathy ◽  
Ubiquitin Proteasome System ◽  
Insulin Metabolism ◽  
Insulin Receptor Substrates ◽  
Ubiquitin Proteasome ◽  
Novel Strategy ◽  
New Strategies

Diabetic cardiomyopathy (DCM) is the leading cause of mortality in diabetes. As the number of cases of diabetes continues to rise, it is urgent to develop new strategies to protect against DCM, which is characterized by cardiac hypertrophy, increased apoptosis, fibrosis, and altered insulin metabolism. The E3 ubiquitin ligases (E3s), one component of the ubiquitin-proteasome system, play vital roles in all of the features of DCM listed above. They also modulate the activity of several transcription factors involved in the pathogenesis of DCM. In addition, the E3s degrade both insulin receptor and insulin receptor substrates and also regulate insulin gene transcription, leading to insulin resistance and insulin deficiency. Therefore, the E3s may be a driving force for DCM. This review summarizes currently available studies to analyze the roles of the E3s in DCM, enriches our knowledge of how DCM develops, and provides a novel strategy to protect heart from diabetes.

SCFβ-TRCP Mediates Ubiquitination and Degradation of the Erythropoietin Receptor and Controls Cell Proliferation.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 464-464
Author(s):  
Frederique Verdier ◽  
Laure Meyer ◽  
Benedicte Deau ◽  
Hana Forejtnikova ◽  
Dominique Dumenil ◽  
...  
Keyword(s):  
Binding Site ◽  
Ubiquitin Ligase ◽  
Blood Cells ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Erythropoietin Receptor ◽  
Erythroid Progenitors ◽  
Ubiquitin Proteasome ◽  
Binding Sequence ◽  
Stimulation Of

Abstract Control of intensity and duration of erythropoietin (Epo) signalling is necessary to tightly regulate red blood cells production. After Epo stimulation of erythroid cells, 2 types of signal are transduced via the Epo receptor (Epo-R): positive signals involved in survival and proliferation, and negative signals involved in signal arrest. We have recently shown that the ubiquitin/ proteasome system plays a major role in the control of Epo-R signalling duration and desensitisation processes. Indeed, after Epo stimulation the Epo-R is ubiquitinated and its intracellular part is degraded by the proteasome, preventing further signal transduction. The remaining part of the receptor, together with associated Epo is internalised and degraded by the lysosomes (Walrafen et al 2005 Blood, 105, 600-608). Our aim was to identify the E3 ubiquitin ligase involved in Epo-R ubiquitination. The Epo-R contains a putative β-Trcp binding site in its intracellular domain. Interestingly, this putative binding sequence is located in a region of the Epo-R that is deleted in erythroid progenitors from patients with familial polycythemia. We show that β-Trcp is responsible for Epo-R ubiquitination upon Epo stimulation. After Epo stimulation, β-Trcp binds to the Epo-R and this binding is dependent on Jak2 activation. Mutation of the Ser 462 residue of the Epo-R, located in the consensus β-Trcp binding site abolished β-Trcp binding, Epo-R ubiquitination and EpoR cleavage by the proteasome. Activation of the mutated Epo-R is prolonged in comparaison with Epo-R WT and BaF3 cells expressing this mutated receptor unable to bind β-Trcp are hypersensitive to Epo. Whether the removal of the β-Trcp binding site contributes to the hypersensitivity to Epo in familial polycythemia is currently under study.]

scholarly journals The Molecular and Pathophysiological Functions of Members of the LNX/PDZRN E3 Ubiquitin Ligase Family

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5938
Author(s):  
Jeongkwan Hong ◽  
Minho Won ◽  
Hyunju Ro
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Ligases ◽  
Ubiquitin Proteasome System ◽  
E3 Ubiquitin Ligases ◽  
Intercellular Signaling ◽  
Cellular Functions ◽  
Ring Type ◽  
Ubiquitin Ligase Activity ◽  
Ubiquitin Proteasome

The ligand of Numb protein-X (LNX) family, also known as the PDZRN family, is composed of four discrete RING-type E3 ubiquitin ligases (LNX1, LNX2, LNX3, and LNX4), and LNX5 which may not act as an E3 ubiquitin ligase owing to the lack of the RING domain. As the name implies, LNX1 and LNX2 were initially studied for exerting E3 ubiquitin ligase activity on their substrate Numb protein, whose stability was negatively regulated by LNX1 and LNX2 via the ubiquitin-proteasome pathway. LNX proteins may have versatile molecular, cellular, and developmental functions, considering the fact that besides these proteins, none of the E3 ubiquitin ligases have multiple PDZ (PSD95, DLGA, ZO-1) domains, which are regarded as important protein-interacting modules. Thus far, various proteins have been isolated as LNX-interacting proteins. Evidence from studies performed over the last two decades have suggested that members of the LNX family play various pathophysiological roles primarily by modulating the function of substrate proteins involved in several different intracellular or intercellular signaling cascades. As the binding partners of RING-type E3s, a large number of substrates of LNX proteins undergo degradation through ubiquitin-proteasome system (UPS) dependent or lysosomal pathways, potentially altering key signaling pathways. In this review, we highlight recent and relevant findings on the molecular and cellular functions of the members of the LNX family and discuss the role of the erroneous regulation of these proteins in disease progression.

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