scholarly journals The Ubiquitin-Proteasome System Plays an Important Role during Various Stages of the Coronavirus Infection Cycle

2010 ◽  
Vol 84 (15) ◽  
pp. 7869-7879 ◽  
Author(s):  
Matthijs Raaben ◽  
Clara C. Posthuma ◽  
Monique H. Verheije ◽  
Eddie G. te Lintelo ◽  
Marjolein Kikkert ◽  
...  
Keyword(s):  
Protein Expression ◽  
Ubiquitin Proteasome System ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Infection Cycle ◽  
Protein Ubiquitination ◽  
Ubiquitin Proteasome ◽  
The Impact ◽  
In Cells

ABSTRACT The ubiquitin-proteasome system (UPS) is a key player in regulating the intracellular sorting and degradation of proteins. In this study we investigated the role of the UPS in different steps of the coronavirus (CoV) infection cycle. Inhibition of the proteasome by different chemical compounds (i.e., MG132, epoxomicin, and Velcade) appeared to not only impair entry but also RNA synthesis and subsequent protein expression of different CoVs (i.e., mouse hepatitis virus [MHV], feline infectious peritonitis virus, and severe acute respiratory syndrome CoV). MHV assembly and release were, however, not appreciably affected by these compounds. The inhibitory effect on CoV protein expression did not appear to result from a general inhibition of translation due to induction of a cellular stress response by the inhibitors. Stress-induced phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) generally results in impaired initiation of protein synthesis, but the sensitivity of MHV infection to proteasome inhibitors was unchanged in cells lacking a phosphorylatable eIF2α. MHV infection was affected not only by inhibition of the proteasome but also by interfering with protein ubiquitination. Viral protein expression was reduced in cells expressing a temperature-sensitive ubiquitin-activating enzyme E1 at the restrictive temperature, as well as in cells in which ubiquitin was depleted by using small interfering RNAs. Under these conditions, the susceptibility of the cells to virus infection was, however, not affected, excluding an important role of ubiquitination in virus entry. Our observations reveal an important role of the UPS in multiple steps of the CoV infection cycle and identify the UPS as a potential drug target to modulate the impact of CoV infection.

scholarly journals Foot-and-Mouth Disease Virus Viroporin 2B Antagonizes RIG-I-Mediated Antiviral Effects by Inhibition of Its Protein Expression

2016 ◽  
Vol 90 (24) ◽  
pp. 11106-11121 ◽  
Author(s):  
Zixiang Zhu ◽  
Guoqing Wang ◽  
Fan Yang ◽  
Weijun Cao ◽  
Ruoqing Mao ◽  
...  
Keyword(s):  
Protein Expression ◽  
Foot And Mouth Disease ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Translation ◽  
Mouth Disease Virus ◽  
2B Protein ◽  
Eukaryotic Translation Initiation ◽  
Cellular Apoptosis

ABSTRACTThe role of retinoic acid-inducible gene I (RIG-I) in foot-and-mouth disease virus (FMDV)-infected cells remains unknown. Here, we showed that RIG-I inhibits FMDV replication in host cells. FMDV infection increased the transcription of RIG-I, while it decreased RIG-I protein expression. A detailed analysis revealed that FMDV leader proteinase (Lpro), as well as 3C proteinase (3Cpro) and 2B protein, decreased RIG-I protein expression. Lproand 3Cproare viral proteinases that can cleave various host proteins and are responsible for several of the viral polyprotein cleavages. However, for the first time, we observed 2B-induced reduction of host protein. Further studies showed that 2B-mediated reduction of RIG-I is specific to FMDV, but not other picornaviruses, including encephalomyocarditis virus, enterovirus 71, and coxsackievirus A16. Moreover, we found the decreased protein level of RIG-I is independent of the cleavage of eukaryotic translation initiation factor 4 gamma, the induction of cellular apoptosis, or the association of proteasome, lysosome, and caspase pathways. A direct interaction was observed between RIG-I and 2B. The carboxyl-terminal amino acids 105 to 114 and amino acids 135 to 144 of 2B were essential for the reduction of RIG-I, while residues 105 to 114 were required for the interaction. These data suggest the antiviral role of RIG-I against FMDV and a novel antagonistic mechanism of FMDV that is mediated by 2B protein.IMPORTANCEThis study demonstrated that RIG-I could suppress FMDV replication during virus infection. FMDV infection increased the transcriptional expression of RIG-I, while it decreased RIG-I protein expression. FMDV 2B protein interacted with RIG-I and induced reduction of RIG-I. 2B-induced reduction of RIG-I was independent of the induction of the cleavage of eukaryotic translation initiation factor 4 gamma or cellular apoptosis. In addition, proteasome, lysosome, and caspase pathways were not involved in this process. This study provides new insight into the immune evasion mediated by FMDV and identifies 2B as an antagonistic factor for FMDV to evade the antiviral response.

scholarly journals Mammalian orthoreovirus Infection is Enhanced in Cells Pre-Treated with Sodium Arsenite

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 563 ◽  
Author(s):  
Michael M. Lutz ◽  
Megan P. Worth ◽  
Meleana M. Hinchman ◽  
John S.L. Parker ◽  
Emily D. Ledgerwood
Keyword(s):  
Protein Expression ◽  
Stress Responses ◽  
Viral Protein ◽  
Sodium Arsenite ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Viral Protein Expression ◽  
Viral Yield ◽  
Pre Treatment ◽  
In Cells

Following reovirus infection, cells activate stress responses that repress canonical translation as a mechanism to limit progeny virion production. Work by others suggests that these stress responses, which are part of the integrated stress response (ISR), may benefit rather than repress reovirus replication. Here, we report that compared to untreated cells, treating cells with sodium arsenite (SA) to activate the ISR prior to infection enhanced viral protein expression, percent infectivity, and viral titer. SA-mediated enhancement was not strain-specific, but was cell-type specific. While SA pre-treatment of cells offered the greatest enhancement, treatment within the first 4 h of infection increased the percent of cells infected. SA activates the heme-regulated eIF2α (HRI) kinase, which phosphorylates eukaryotic translation initiation factor 2 alpha (eIF2α) to induce stress granule (SG) formation. Heat shock (HS), another activator of HRI, also induced eIF2α phosphorylation and SGs in cells. However, HS had no effect on percent infectivity or viral yield but did enhance viral protein expression. These data suggest that SA pre-treatment perturbs the cell in a way that is beneficial for reovirus and that this enhancement is independent of SG induction. Understanding how to manipulate the cellular stress responses during infection to enhance replication could help to maximize the oncolytic potential of reovirus.

scholarly journals The Ubiquitin Proteasome System in Ischemic and Dilated Cardiomyopathy

2019 ◽  
Vol 20 (24) ◽  
pp. 6354 ◽  
Author(s):  
Sabine Spänig ◽  
Kristina Kellermann ◽  
Maja-Theresa Dieterlen ◽  
Thilo Noack ◽  
Sven Lehmann ◽  
...  
Keyword(s):  
Protein Expression ◽  
Ubiquitin Proteasome System ◽  
Translation Initiation Factor ◽  
Myocardial Tissue ◽  
Activation Markers ◽  
E3 Ligases ◽  
Proteasomal Activity ◽  
Ubiquitin Proteasome ◽  
Statistical Trends ◽  
And Control

Dilated (DCM) and ischemic cardiomyopathies (ICM) are associated with cardiac remodeling, where the ubiquitin–proteasome system (UPS) holds a central role. Little is known about the UPS and its alterations in patients suffering from DCM or ICM. The aim of this study is to characterize the UPS activity in human heart tissue from cardiomyopathy patients. Myocardial tissue from ICM (n = 23), DCM (n = 28), and control (n = 14) patients were used to quantify ubiquitinylated proteins, E3-ubiquitin-ligases muscle-atrophy-F-box (MAFbx)/atrogin-1, muscle-RING-finger-1 (MuRF1), and eukaryotic-translation-initiation-factor-4E (eIF4E), by Western blot. Furthermore, the proteasomal chymotrypsin-like and trypsin-like peptidase activities were determined fluorometrically. Enzyme activity of NAD(P)H oxidase was assessed as an index of reactive oxygen species production. The chymotrypsin- (p = 0.71) and caspase-like proteasomal activity (p = 0.93) was similar between the groups. Trypsin-like proteasomal activity was lower in ICM (0.78 ± 0.11 µU/mg) compared to DCM (1.06 ± 0.08 µU/mg) and control (1.00 ± 0.06 µU/mg; p = 0.06) samples. Decreased ubiquitin expression in both cardiomyopathy groups (ICM vs. control: p < 0.001; DCM vs. control: p < 0.001), as well as less ubiquitin-positive deposits in ICM-damaged tissue (ICM: 4.19% ± 0.60%, control: 6.28% ± 0.40%, p = 0.022), were detected. E3-ligase MuRF1 protein expression (p = 0.62), NADPH-oxidase activity (p = 0.63), and AIF-positive cells (p = 0.50). Statistical trends were detected for reduced MAFbx protein expression in the DCM-group (p = 0.07). Different levels of UPS components, E3 ligases, and UPS activation markers were observed in myocardial tissue from patients affected by DCM and ICM, suggesting differential involvement of the UPS in the underlying pathologies.

scholarly journals Translational control in the tumor microenvironment promotes lung metastasis: Phosphorylation of eIF4E in neutrophils

2018 ◽  
Vol 115 (10) ◽  
pp. E2202-E2209 ◽  
Author(s):  
Nathaniel Robichaud ◽  
Brian E. Hsu ◽  
Roman Istomine ◽  
Fernando Alvarez ◽  
Julianna Blagih ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Progression ◽  
Translational Control ◽  
Lung Metastases ◽  
Phosphorylation Site ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Metastatic Progression ◽  
The Impact ◽  
In Cells

The translation of mRNAs into proteins serves as a critical regulatory event in gene expression. In the context of cancer, deregulated translation is a hallmark of transformation, promoting the proliferation, survival, and metastatic capabilities of cancer cells. The best-studied factor involved in the translational control of cancer is the eukaryotic translation initiation factor 4E (eIF4E). We and others have shown that eIF4E availability and phosphorylation promote metastasis in mouse models of breast cancer by selectively augmenting the translation of mRNAs involved in invasion and metastasis. However, the impact of translational control in cell types within the tumor microenvironment (TME) is unknown. Here, we demonstrate that regulatory events affecting translation in cells of the TME impact cancer progression. Mice bearing a mutation in the phosphorylation site of eIF4E (S209A) in cells comprising the TME are resistant to the formation of lung metastases in a syngeneic mammary tumor model. This is associated with reduced survival of prometastatic neutrophils due to decreased expression of the antiapoptotic proteins BCL2 and MCL1. Furthermore, we demonstrate that pharmacological inhibition of eIF4E phosphorylation prevents metastatic progression in vivo, supporting the development of phosphorylation inhibitors for clinical use.

scholarly journals PARylation prevents the proteasomal degradation of topoisomerase I DNA-protein crosslinks and induces their deubiquitylation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yilun Sun ◽  
Jiji Chen ◽  
Shar-yin N. Huang ◽  
Yijun P. Su ◽  
Wenjie Wang ◽  
...  
Keyword(s):  
Single Molecule ◽  
Topoisomerase I ◽  
Ubiquitin Proteasome System ◽  
Live Cells ◽  
Ubiquitin Proteasome ◽  
Repair Factor ◽  
The Impact ◽  
Protein Crosslinks ◽  
Potential Regulatory Role

AbstractPoly(ADP)-ribosylation (PARylation) regulates chromatin structure and recruits DNA repair proteins. Using single-molecule fluorescence microscopy to track topoisomerase I (TOP1) in live cells, we found that sustained PARylation blocked the repair of TOP1 DNA-protein crosslinks (TOP1-DPCs) in a similar fashion as inhibition of the ubiquitin-proteasome system (UPS). PARylation of TOP1-DPC was readily revealed by inhibiting poly(ADP-ribose) glycohydrolase (PARG), indicating the otherwise transient and reversible PARylation of the DPCs. As the UPS is a key repair mechanism for TOP1-DPCs, we investigated the impact of TOP1-DPC PARylation on the proteasome and found that the proteasome is unable to associate with and digest PARylated TOP1-DPCs. In addition, PARylation recruits the deubiquitylating enzyme USP7 to reverse the ubiquitylation of PARylated TOP1-DPCs. Our work identifies PARG as repair factor for TOP1-DPCs by enabling the proteasomal digestion of TOP1-DPCs. It also suggests the potential regulatory role of PARylation for the repair of a broad range of DPCs.

scholarly journals S-Nitrosation and Ubiquitin-Proteasome System Interplay in Neuromuscular Disorders

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Salvatore Rizza ◽  
Costanza Montagna ◽  
Giuseppina Di Giacomo ◽  
Claudia Cirotti ◽  
Giuseppe Filomeni
Keyword(s):  
Posttranslational Modifications ◽  
Protein Quality ◽  
Neuromuscular Disorders ◽  
Ubiquitin Proteasome System ◽  
E3 Ligases ◽  
Protein Ubiquitination ◽  
Ubiquitin Proteasome ◽  
Protein Quality Control System ◽  
The Impact ◽  
Lines Of Evidence

ProteinS-nitrosation is deemed as a prototype of posttranslational modifications governing cell signaling. It takes place on specific cysteine residues that covalently incorporate a nitric oxide (NO) moiety to formS-nitrosothiol derivatives and depends on the ratio between NO produced by NO synthases and nitrosothiol removal catalyzed by denitrosating enzymes. A large number of cysteine-containing proteins are found to undergoS-nitrosation and, among them, the enzymes catalyzing ubiquitination, mainly the class of ubiquitin E3 ligases and the 20S component of the proteasome, have been reported to be redox modulated in their activity. In this review we will outline the processes regulatingS-nitrosation and try to debate whether and how it affects protein ubiquitination and degradation via the proteasome. In particular, since muscle and neuronal health largely depends on the balance between protein synthesis and breakdown, here we will discuss the impact ofS-nitrosation in the efficiency of protein quality control system, providing lines of evidence and speculating about its involvement in the onset and maintenance of neuromuscular dysfunctions.

scholarly journals Ubiquitin-mediated regulation of autophagy

2019 ◽  
Vol 26 (1) ◽  
Author(s):  
Ruey-Hwa Chen ◽  
Yu-Hsuan Chen ◽  
Tzu-Yu Huang
Keyword(s):  
Reciprocal Cross ◽  
Ubiquitin Proteasome System ◽  
Degradation Pathway ◽  
Degradation Pathways ◽  
Cell Homeostasis ◽  
Polyubiquitin Chains ◽  
Selective Autophagy ◽  
Protein Ubiquitination ◽  
Ubiquitin Proteasome

Abstract Autophagy is a major degradation pathway that utilizes lysosome hydrolases to degrade cellular constituents and is often induced under cellular stress conditions to restore cell homeostasis. Another prime degradation pathway in the cells is ubiquitin-proteasome system (UPS), in which proteins tagged by certain types of polyubiquitin chains are selectively recognized and removed by proteasome. Although the two degradation pathways are operated independently with different sets of players, recent studies have revealed reciprocal cross talks between UPS and autophagy at multiple layers. In this review, we summarize the roles of protein ubiquitination and deubiquitination in controlling the initiation, execution, and termination of bulk autophagy as well as the role of ubiquitination in signaling certain types of selective autophagy. We also highlight how dysregulation of ubiquitin-mediated autophagy pathways is associated with a number of human diseases and the potential of targeting these pathways for disease intervention.

scholarly journals Hypoxia-induced alterations in the lung ubiquitin proteasome system during pulmonary hypertension pathogenesis

2018 ◽  
Vol 8 (3) ◽  
pp. 204589401878826 ◽  
Author(s):  
Brandy E. Wade ◽  
Jingru Zhao ◽  
Jing Ma ◽  
C. Michael Hart ◽  
Roy L. Sutliff
Keyword(s):  
Mass Spectrometry ◽  
Pulmonary Hypertension ◽  
Ubiquitin Proteasome System ◽  
Global Changes ◽  
Clinical Disorder ◽  
Ubiquitinated Proteins ◽  
Protein Ubiquitination ◽  
Ubiquitin Proteasome ◽  
Protein Alterations

Pulmonary hypertension (PH) is a clinical disorder characterized by sustained increases in pulmonary vascular resistance and pressure that can lead to right ventricular (RV) hypertrophy and ultimately RV failure and death. The molecular pathogenesis of PH remains incompletely defined, and existing treatments are associated with suboptimal outcomes and persistent morbidity and mortality. Reports have suggested a role for the ubiquitin proteasome system (UPS) in PH, but the extent of UPS-mediated non-proteolytic protein alterations during PH pathogenesis has not been previously defined. To further examine UPS alterations, the current study employed C57BL/6J mice exposed to normoxia or hypoxia for 3 weeks. Lung protein ubiquitination was evaluated by mass spectrometry to identify differentially ubiquitinated proteins relative to normoxic controls. Hypoxia stimulated differential ubiquitination of 198 peptides within 131 proteins ( p < 0.05). These proteins were screened to identify candidates within pathways involved in PH pathogenesis. Some 51.9% of the differentially ubiquitinated proteins were implicated in at least one known pathway contributing to PH pathogenesis, and 13% were involved in three or more PH pathways. Anxa2, App, Jak1, Lmna, Pdcd6ip, Prkch1, and Ywhah were identified as mediators in PH pathways that undergo differential ubiquitination during PH pathogenesis. To our knowledge, this is the first study to report global changes in protein ubiquitination in the lung during PH pathogenesis. These findings suggest signaling nodes that are dynamically regulated by the UPS during PH pathogenesis. Further exploration of these differentially ubiquitinated proteins and related pathways can provide new insights into the role of the UPS in PH pathogenesis.

scholarly journals Evaluation of the impact of the proteasome inhibitor on calcium channel expression in cardiomyocytes treated with doxorubicin

2018 ◽  
Vol 31 (1) ◽  
pp. 18-21
Author(s):  
Agnieszka Korga ◽  
Milena Soroka ◽  
Karolina Wicha ◽  
Ewelina Humeniuk ◽  
Grzegorz Adamczuk ◽  
...  
Keyword(s):  
Protein Expression ◽  
Calcium Channel ◽  
Proteasome Inhibitor ◽  
Anthracycline Cardiomyopathy ◽  
Channel Expression ◽  
Embryonic Cardiomyocytes ◽  
Ubiquitin Proteasome ◽  
Mrna And Protein Expression ◽  
The Impact

AbstractOne of the less known mechanisms of doxorubicin action is the effect on the functioning of the ubiquitin-proteasome degradation system (UPS). So far, the role of impaired proteasome activity in the development of anthracycline cardiomyopathy has not been clarified. It has been shown, however, that doxorubicin decreases the expression of proteins, including the expression of the calcium channel. However, it has not been established whether the observed disturbances are due to the activation of the UPS system by doxorubicin, or due to inhibition of translation or transcription. Therefore, the aim of the study was to evaluate the mRNA and protein expression of plasmalemmal (NaCaX, L-type) and sarcoplasmic reticulum (SERCA2, RyR2) channels in rat embryonic cardiomyocytes treated with doxorubicin and the proteasome inhibitor – bortezomib. The study was conducted utilizing the rat cardiomyocyte H9C2 line that was treated with doxorubicin and bortezomib in different concentrations. After 24 hours incubation, mRNA and protein expression analysis followed. The study did not show any universal mechanism of doxorubicin influence on calcium channel expression. With regard to the Na/Ca exchanger, we saw that DOX decreased the protein level in a proteasome activitydependent manner. Moreover, we noted that the SERCA2 protein expression level was regulated by degradation intensity, however at the same time, no significant effect of doxorubicin on the level of this protein was demonstrated.

Glomerular epithelial cell injury associated with mutant α-actinin-4

2009 ◽  
Vol 297 (4) ◽  
pp. F987-F995 ◽  
Author(s):  
Andrey V. Cybulsky ◽  
Tomoko Takano ◽  
Joan Papillon ◽  
Krikor Bijian ◽  
Julie Guillemette ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Er Stress ◽  
Cell Injury ◽  
Proteasome Inhibition ◽  
Ubiquitin Proteasome System ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Glomerular Epithelial Cell ◽  
Cos Cells ◽  
Ubiquitin Proteasome

Focal segmental glomerulosclerosis (FSGS) may be associated with glomerular epithelial cell (GEC; podocyte) apoptosis due to acquired injury or mutations in α-actinin-4. This study addresses how FSGS-associated mutant α-actinin-4 may induce GEC injury, focusing on endoplasmic reticulum (ER) stress and metabolism of mutant α-actinin-4 via the ubiquitin-proteasome system. In a model of experimental FSGS induced by expression of an α-actinin-4 K256E transgene in podocytes, we show induction of ER stress, including upregulation of ER chaperones (bip, grp94), phosphorylation of the eukaryotic translation initiation factor-2α subunit, and induction of the proapop totic gene C/EBP homologous protein-10 (CHOP). To address mechanisms of ER stress, we studied signaling in cultured GEC and COS cells expressing α-actinin-4 K256E. Previously, we showed that expression of this α-actinin-4 mutant in GEC increased apoptosis. In the present study, we show that α-actinin-4 K256E upregulates grp94 and CHOP expression in COS cells and significantly exacerbates induction of bip and CHOP in GEC in the presence of tunicamycin. ER stress was associated with aggregation and ubiquitination of α-actinin-4 K256E and impairment of the ubiquitin-proteasome system. In addition, α-actinin-4 K256E exacerbated apoptosis in the context of mild proteasome inhibition. Thus α-actinin-4 K256E triggers several metabolic abnormalities, which may lead to GEC injury and glomerulosclerosis.

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