scholarly journals The Ubiquitin-Proteasome System Is Necessary for Efficient Replication of Human Astrovirus

2017 ◽  
Vol 92 (2) ◽  
Author(s):  
Luis A. Casorla-Pérez ◽  
Tomás López ◽  
Susana López ◽  
Carlos F. Arias
Keyword(s):  
Protein Synthesis ◽  
Viral Protein ◽  
Proteasome Inhibitors ◽  
Ubiquitin Proteasome System ◽  
Progeny Production ◽  
Viral Protein Synthesis ◽  
Viral Progeny ◽  
Efficient Replication ◽  
Ubiquitin Proteasome ◽  
Human Astrovirus

ABSTRACT Astroviruses, members of the family Astroviridae, represent an important cause of human gastroenteritis in the world. The cellular factors required for astrovirus replication have been poorly studied. In this work, we evaluated the relevance of the ubiquitin-proteasome system (UPS) in the replication of Yuc8, a human astrovirus serotype 8 strain. We found that proteasome inhibitors decrease the production of infectious viral progeny at a step in the replication cycle subsequent to virus entry. The inhibition of proteasome activity decreases viral RNA levels and viral protein synthesis; similarly, the inhibition of ubiquitination by chemical inhibitors or RNA interference (RNAi) reduces the production of viral progeny as well as viral protein synthesis. The effect on viral progeny production induced by proteasome inhibitors is not explained by a reduction in the pool of monoubiquitin or the induction of early apoptosis or autophagy. Our observations are consistent with the need of the proteolytic activity of the UPS for the efficient replication of the virus and suggest that UPS is necessary for the production of genomic and subgenomic RNA but not for antigenomic RNA. IMPORTANCE Astroviruses are a major cause of gastroenteritis in young humans and animals, and recently, it was associated with fatal encephalitis in humans. The role of the ubiquitin-proteasome system in the replication of these viruses has not been studied previously. In this work, we present evidence that supports that the proteolytic activity of the proteasome is necessary for efficient viral progeny production and that this proteolytic system is required for the accumulation of both genomic and subgenomic viral RNAs.

scholarly journals Asparagine Is a Critical Limiting Metabolite for Vaccinia Virus Protein Synthesis during Glutamine Deprivation

2019 ◽  
Vol 93 (13) ◽  
Author(s):  
Anil Pant ◽  
Shuai Cao ◽  
Zhilong Yang
Keyword(s):  
Protein Synthesis ◽  
Vaccinia Virus ◽  
Virus Replication ◽  
Viral Protein ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Host Cells ◽  
Viral Protein Synthesis ◽  
Animal Pathogens ◽  
Efficient Replication

ABSTRACTViruses actively interact with host metabolism because viral replication relies on host cells to provide nutrients and energy. Vaccinia virus (VACV; the prototype poxvirus) prefers glutamine to glucose for efficient replication to the extent that VACV replication is hindered in glutamine-free medium. Remarkably, our data show that VACV replication can be fully rescued from glutamine depletion by asparagine supplementation. By global metabolic profiling, as well as genetic and chemical manipulation of the asparagine supply, we provide evidence demonstrating that the production of asparagine, which exclusively requires glutamine for biosynthesis, accounts for VACV’s preference of glutamine to glucose rather than glutamine’s superiority over glucose in feeding the tricarboxylic acid (TCA) cycle. Furthermore, we show that sufficient asparagine supply is required for efficient VACV protein synthesis. Our study highlights that the asparagine supply, the regulation of which has been evolutionarily tailored in mammalian cells, presents a critical barrier to VACV replication due to a high asparagine content of viral proteins and a rapid demand of viral protein synthesis. The identification of asparagine availability as a critical limiting factor for efficient VACV replication suggests a new direction of antiviral strategy development.IMPORTANCEViruses rely on their infected host cells to provide nutrients and energy for replication. Vaccinia virus, the prototypic member of the poxviruses, which comprise many significant human and animal pathogens, prefers glutamine to glucose for efficient replication. Here, we show that the preference is not because glutamine is superior to glucose as the carbon source to fuel the tricarboxylic acid cycle for vaccinia virus replication. Rather interestingly, the preference is because the asparagine supply for efficient viral protein synthesis becomes limited in the absence of glutamine, which is necessary for asparagine biosynthesis. We provide further genetic and chemical evidence to demonstrate that asparagine availability plays a critical role in efficient vaccinia virus replication. This discovery identifies a weakness of vaccinia virus and suggests a possible direction to intervene in poxvirus infection.

scholarly journals A Functional Ubiquitin-Proteasome System is Required for Efficient Replication of New World Mayaro and Una Alphaviruses

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 370 ◽  
Author(s):  
Yessica Y. Llamas-González ◽  
Dalkiria Campos ◽  
Juan M. Pascale ◽  
Juan Arbiza ◽  
José González-Santamaría
Keyword(s):  
Plaque Assay ◽  
Proteasome Inhibitors ◽  
Ubiquitin Proteasome System ◽  
Assay Method ◽  
Efficient Replication ◽  
Serological Studies ◽  
Ubiquitin Proteasome ◽  
Dose Dependent Decrease ◽  
Dose Dependent

Mayaro (MAYV) and Una (UNAV) are emerging arboviruses belonging to the Alphavirus genus of the Togaviridae family. These viruses can produce febrile disease with symptoms such as fever, headache, myalgia, skin rash and incapacitating poly-arthralgia. Serological studies indicate that both viruses are circulating in different countries in Latin America. Viruses need the host cell machinery and resources to replicate effectively. One strategy to find new antivirals consists of identifying key cellular pathways or factors that are essential for virus replication. In this study, we analyzed the role of the ubiquitin-proteasome system (UPS) in MAYV and UNAV replication. Vero-E6 or HeLa cells were treated with the proteasome inhibitors MG132 or Lactacystin, and viral progeny production was quantified using a plaque assay method. In addition, the synthesis of viral proteins was analyzed by Western blot and confocal microscopy. Our results indicate that treatment with proteasome inhibitors decreases MAYV and UNAV protein synthesis, and also causes a significant dose-dependent decrease in MAYV and UNAV replication. Proteasome activity seems to be important at the early stages of MAYV replication. These findings suggest that the ubiquitin-proteasome system is a possible pharmacological target to inhibit these neglected alphaviruses.

Initiation of Mammalian Viral Protein Synthesis

1971 ◽  
Vol 229 (8) ◽  
pp. 239-241 ◽  
Author(s):  
HANS CAFFIER ◽  
HESCHEL J. RASKAS ◽  
J. THOMAS PARSONS ◽  
MAURICE GREEN
Keyword(s):  
Protein Synthesis ◽  
Viral Protein ◽  
Viral Protein Synthesis

scholarly journals Effect of the Viral Hemorrhagic Septicemia Virus Nonvirion Protein on Translation via PERK-eIF2α Pathway

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 499 ◽  
Author(s):  
Shelby Powell Kesterson ◽  
Jeffery Ringiesn ◽  
Vikram N. Vakharia ◽  
Brian S. Shepherd ◽  
Douglas W. Leaman ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Viral Protein ◽  
Molecular Mechanisms ◽  
Freshwater Ecosystems ◽  
Innate Immune ◽  
Host Cells ◽  
Initiation Factor ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Viral Protein Synthesis ◽  
Viral Hemorrhagic Septicemia

Viral hemorrhagic septicemia virus (VHSV) is one of the most deadly infectious fish pathogens, posing a serious threat to the aquaculture industry and freshwater ecosystems worldwide. Previous work showed that VHSV sub-genotype IVb suppresses host innate immune responses, but the exact mechanism by which VHSV IVb inhibits antiviral response remains incompletely characterized. As with other novirhabdoviruses, VHSV IVb contains a unique and highly variable nonvirion (NV) gene, which is implicated in viral replication, virus-induced apoptosis and regulating interferon (IFN) production. However, the molecular mechanisms underlying the role of IVb NV gene in regulating viral or cellular processes is poorly understood. Compared to the wild-type recombinant (rWT) VHSV, mutant VHSV lacking a functional IVb NV reduced IFN expression and compromised innate immune response of the host cells by inhibiting translation. VHSV IVb infection increased phosphorylated eukaryotic initiation factor 2α (p-eIF2α), resulting in host translation shutoff. However, VHSV IVb protein synthesis proceeds despite increasing phosphorylation of eIF2α. During VHSV IVb infection, eIF2α phosphorylation was mediated via PKR-like endoplasmic reticulum kinase (PERK) and was required for efficient viral protein synthesis, but shutoff of host translation and IFN signaling was independent of p-eIF2α. Similarly, IVb NV null VHSV infection induced less p-eIF2α, but exhibited decreased viral protein synthesis despite increased levels of viral mRNA. These findings show a role for IVb NV in VHSV pathogenesis by utilizing the PERK-eIF2α pathway for viral-mediated host shutoff and interferon signaling to regulate host cell response.

scholarly journals Ubiquitination and Ubiquitin-Like Modifications in Multiple Myeloma: Biology and Therapy

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3764
Author(s):  
Matthias Wirth ◽  
Markus Schick ◽  
Ulrich Keller ◽  
Jan Krönke
Keyword(s):  
Multiple Myeloma ◽  
Translational Regulation ◽  
Proteasome Inhibitors ◽  
Ubiquitin Proteasome System ◽  
Organ Damage ◽  
Post Translational Modifications ◽  
Damage Repair ◽  
Ubiquitin Proteasome ◽  
New Treatments ◽  
Effective Drugs

Multiple myeloma is a genetically heterogeneous plasma cell malignancy characterized by organ damage and a massive production of (in-)complete monoclonal antibodies. Coping with protein homeostasis and post-translational regulation is therefore essential for multiple myeloma cells to survive. Furthermore, post-translational modifications such as ubiquitination and SUMOylation play key roles in essential pathways in multiple myeloma, including NFκB signaling, epigenetic regulation, as well as DNA damage repair. Drugs modulating the ubiquitin–proteasome system, such as proteasome inhibitors and thalidomide analogs, are approved and highly effective drugs in multiple myeloma. In this review, we focus on ubiquitin and ubiquitin-like modifications in the biology and current developments of new treatments for multiple myeloma.

scholarly journals Regulation of Ubiquitin-Proteasome System–mediated Degradation by Cytosolic Stress

2007 ◽  
Vol 18 (11) ◽  
pp. 4279-4291 ◽  
Author(s):  
Sean M. Kelly ◽  
Judy K. VanSlyke ◽  
Linda S. Musil
Keyword(s):  
Heat Shock ◽  
Secretory Pathway ◽  
Proteasome Inhibitors ◽  
Ubiquitin Proteasome System ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Junction Protein ◽  
Ubiquitin Proteasome ◽  
Gap Junction Protein ◽  
Cystic Fibrosis Transmembrane

ER-associated, ubiquitin-proteasome system (UPS)-mediated degradation of the wild-type (WT) gap junction protein connexin32 (Cx32) is inhibited by mild forms of cytosolic stress at a step before its dislocation into the cytosol. We show that the same conditions (a 30-min, 42°C heat shock or oxidative stress induced by arsenite) also reduce the endoplasmic reticulum (ER)-associated turnover of disease-causing mutants of Cx32 and the cystic fibrosis transmembrane conductance regulator (CFTR), as well as that of WT CFTR and unassembled Ig light chain. Stress-stabilized WT Cx32 and CFTR, but not the mutant/unassembled proteins examined, could traverse the secretory pathway. Heat shock also slowed the otherwise rapid UPS-mediated turnover of the cytosolic proteins myoD and GFPu, but not the degradation of an ubiquitination-independent construct (GFP-ODC) closely related to the latter. Analysis of mutant Cx32 from cells exposed to proteasome inhibitors and/or cytosolic stress indicated that stress reduces degradation at the level of substrate polyubiquitination. These findings reveal a new link between the cytosolic stress-induced heat shock response, ER-associated degradation, and polyubiquitination. Stress-denatured proteins may titer a limiting component of the ubiquitination machinery away from pre-existing UPS substrates, thereby sparing the latter from degradation.

Inhibition of viral protein synthesis in monkey cells treated with interferon late in simian virus 40 lytic cycle

Cell ◽  
1977 ◽  
Vol 12 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Emanuel Yakobson ◽  
Carol Prives ◽  
Jacob R. Hartman ◽  
Ernest Winocour ◽  
Michel Revel
Keyword(s):  
Protein Synthesis ◽  
Viral Protein ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Lytic Cycle ◽  
Viral Protein Synthesis

scholarly journals Proteasome activity is altered in skeletal muscle tissue of tumour-bearing rats a leucine-rich diet

2004 ◽  
Vol 11 (4) ◽  
pp. 887-895 ◽  
Author(s):  
G Ventrucci ◽  
M A R Mello ◽  
M C C Gomes-Marcondes
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Tumour Growth ◽  
Ubiquitin Proteasome System ◽  
Protein Breakdown ◽  
Pregnant Rats ◽  
Α Subunit ◽  
Proteasome Subunit ◽  
Tumour Bearing ◽  
Ubiquitin Proteasome

Leucine can modulate skeletal muscle metabolism by enhancing protein synthesis and decreasing proteolysis. In this study, we investigated the effects of leucine on the ubiquitin–proteasome system in skeletal muscle of pregnant tumour-bearing rats fed a leucine-rich diet. Pregnant Wistar rats were distributed into three groups that were fed a semi-purified control diet (C, control; W, Walker tumour-bearing; P, pair-fed) and three other groups of pregnant rats fed a semi-purified leucine-rich diet (L, leucine; WL, Walker tumour-bearing; PL, pair-fed). The tumour-bearing rats were injected subcutaneously with a suspension of Walker 256 tumour cells. Protein synthesis and degradation were measured in gastrocnemius muscle; the total protein content and tissue chymotrypsin-like and alkaline phosphatase enzyme activities were also determined. Muscle protein extracts were run on SDS-PAGE to assess the expression of the myosin heavy chain (MHC), 20S α proteasome subunit, 19S MSSI ATPase regulator subunit and 11S α subunit. Although tumour growth decreased the incorporation of [3H]-Phe, the concomitant feeding of a leucine-rich diet increased the rate of protein synthesis. Muscle proteolysis in both tumour-bearing groups was increased more than in the respective control groups. Conversely, the leucine-rich diet caused less protein breakdown in the WL group than in the W group. Only the W group showed a significant reduction (71%) in the myosin content. In WL rats, the 20S proteasome content (32 kDa band) was reduced, while the expression of the 19S subunit was 3-fold less than in the W group and the 11S proteasome subunit reduced, to around 32% less than in the W group. These findings clearly indicate that leucine can stimulate protein synthesis and inhibit protein breakdown in pregnant rats, probably by modulating the activation of the ubiquitin–proteasome system during tumour growth.

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