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Journal of Virology Jan 2024SARS-CoV-2 belongs to the subgenus , which universally encodes the accessory protein ORF6. SARS-CoV-2 ORF6 is an antagonist of the interferon (IFN)-mediated antiviral...
SARS-CoV-2 belongs to the subgenus , which universally encodes the accessory protein ORF6. SARS-CoV-2 ORF6 is an antagonist of the interferon (IFN)-mediated antiviral response and plays an important role in viral infections. However, the mechanism by which the host counteracts the function of ORF6 to restrict viral replication remains unclear. In this study, we found that most ORF6 proteins encoded by sarbecoviruses could be ubiquitinated and subsequently degraded via the proteasome pathway. Through extensive screening, we identified that the deubiquitinase USP1, which effectively and broadly deubiquitinates sarbecovirus ORF6 proteins, stabilizes ORF6 proteins, resulting in enhanced viral replication. Therefore, ubiquitination and deubiquitination of ORF6 are important for antagonizing IFN-mediated antiviral signaling and influencing the virulence of SARS-CoV-2. These findings highlight an essential molecular mechanism and may provide a novel target for therapeutic interventions against viral infections.IMPORTANCEThe ORF6 proteins encoded by sarbecoviruses are essential for effective viral replication and infection and are important targets for developing effective intervention strategies. In this study, we confirmed that sarbecovirus ORF6 proteins are important antagonists of the host immune response and identified the regulatory mechanisms of ubiquitination and deubiquitination of most sarbecovirus ORF6 proteins. Moreover, we revealed that DUB USP1 prevents the proteasomal degradation of all ORF6 proteins, thereby promoting the virulence of SARS-CoV-2. Thus, impeding ORF6 function is helpful for attenuating the virulence of sarbecoviruses. Therefore, our findings provide a deeper understanding of the molecular mechanisms underlying sarbecovirus infections and offer potential new therapeutic targets for the prevention and treatment of these infections.
Topics: Humans; Deubiquitinating Enzymes; Interferons; SARS-CoV-2; Severe acute respiratory syndrome-related coronavirus; Ubiquitin-Specific Proteases; Viral Proteins; Virus Diseases
PubMed: 38084957
DOI: 10.1128/jvi.01437-23 -
Cell Death Discovery Sep 2023An essential protein regulatory system in cells is the ubiquitin-proteasome pathway. The substrate is modified by the ubiquitin ligase system (E1-E2-E3) in this pathway,... (Review)
Review
An essential protein regulatory system in cells is the ubiquitin-proteasome pathway. The substrate is modified by the ubiquitin ligase system (E1-E2-E3) in this pathway, which is a dynamic protein bidirectional modification regulation system. Deubiquitinating enzymes (DUBs) are tasked with specifically hydrolyzing ubiquitin molecules from ubiquitin-linked proteins or precursor proteins and inversely regulating protein degradation, which in turn affects protein function. The ubiquitin-specific peptidase 32 (USP32) protein level is associated with cell cycle progression, proliferation, migration, invasion, and other cellular biological processes. It is an important member of the ubiquitin-specific protease family. It is thought that USP32, a unique enzyme that controls the ubiquitin process, is closely linked to the onset and progression of many cancers, including small cell lung cancer, gastric cancer, breast cancer, epithelial ovarian cancer, glioblastoma, gastrointestinal stromal tumor, acute myeloid leukemia, and pancreatic adenocarcinoma. In this review, we focus on the multiple mechanisms of USP32 in various tumor types and show that USP32 controls the stability of many distinct proteins. Therefore, USP32 is a key and promising therapeutic target for tumor therapy, which could provide important new insights and avenues for antitumor drug development. The therapeutic importance of USP32 in cancer treatment remains to be further proven. In conclusion, there are many options for the future direction of USP32 research.
PubMed: 37679322
DOI: 10.1038/s41420-023-01629-1 -
Cell Death & Disease Aug 2023Accumulating evidence has shown that the quality of proteins must be tightly monitored and controlled to maintain cellular proteostasis. Misfolded proteins and protein...
Accumulating evidence has shown that the quality of proteins must be tightly monitored and controlled to maintain cellular proteostasis. Misfolded proteins and protein aggregates are targeted for degradation through the ubiquitin proteasome (UPS) and autophagy-lysosome systems. The ubiquitination and deubiquitinating enzymes (DUBs) have been reported to play pivotal roles in the regulation of the UPS system. However, the function of DUBs in the regulation of autophagy remain to be elucidated. In this study, we found that knockdown of Leon/USP5 caused a marked increase in the formation of autophagosomes and autophagic flux under well-fed conditions. Genetic analysis revealed that overexpression of Leon suppressed Atg1-induced cell death in Drosophila. Immunoblotting assays further showed a strong interaction between Leon/USP5 and the autophagy initiating kinase Atg1/ULK1. Depletion of Leon/USP5 led to increased levels of Atg1/ULK1. Our findings indicate that Leon/USP5 is an autophagic DUB that interacts with Atg1/ULK1, negatively regulating the autophagic process.
Topics: Animals; Autophagy; Autophagosomes; Cell Death; Drosophila; Lysosomes; Proteasome Endopeptidase Complex; Ubiquitin; Deubiquitinating Enzymes; Autophagy-Related Protein-1 Homolog; Drosophila Proteins; Ubiquitin-Specific Proteases
PubMed: 37607937
DOI: 10.1038/s41419-023-06062-x -
Cell Communication and Signaling : CCS Aug 2023Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal human malignancies, and with quite limited treatment alternatives. The proteasome is responsible...
Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal human malignancies, and with quite limited treatment alternatives. The proteasome is responsible for most of the protein degradation in eukaryotic cells and required for the maintenance of intracellular homeostasis. However, its potential role in HCC is largely unknown. In the current study, we identified eukaryotic translation initiation factor 3 subunit H (EIF3H), belonging to the JAB1/MPN/MOV34 (JAMM) superfamily, as a bona fide deubiquitylase of O-GlcNAc transferase (OGT) in HCC. We explored that EIF3H was positively associated with OGT in HCC and was related to the unfavorable prognosis. EIF3H could interact with, deubiquitylate, and stabilize OGT in a deubiquitylase-dependent manner. Specifically, EIF3H was associated with the GT domain of ERα via its JAB/MP domain, thus inhibiting the K48-linked ubiquitin chain on OGT. Besides, we demonstrated that the knockdown of EIF3H significantly reduced OGT protein expression, cell proliferation and invasion, and caused G1/S arrest of HCC. We also found that the deletion of EIF3H prompted ferroptosis in HCC cells. Finally, the effects of EIF3H depletion could be reversed by further OGT overexpression, implying that the OGT status is indispensable for EIF3H function in HCC carcinogenesis. In summary, our study described the oncogenic function of EIF3H and revealed an interesting post-translational mechanism between EIF3H, OGT, and ferroptosis in HCC. Targeting the EIF3H may be a promising approach in HCC. Video Abstract.
Topics: Humans; Carcinoma, Hepatocellular; Cell Line, Tumor; Deubiquitinating Enzymes; Ferroptosis; Liver Neoplasms; Eukaryotic Initiation Factor-3
PubMed: 37559097
DOI: 10.1186/s12964-023-01220-2 -
Nucleic Acids Research Oct 2023Plant pathogens are challenged by host-derived iron starvation or excess during infection, but the mechanism through which pathogens counteract iron stress is unclear....
Plant pathogens are challenged by host-derived iron starvation or excess during infection, but the mechanism through which pathogens counteract iron stress is unclear. Here, we found that Fusarium graminearum encounters iron excess during the colonization of wheat heads. Deletion of heme activator protein X (FgHapX), siderophore transcription factor A (FgSreA) or both attenuated virulence. Further, we found that FgHapX activates iron storage under iron excess by promoting histone H2B deubiquitination (H2B deub1) at the promoter of the responsible gene. Meanwhile, FgSreA is shown to inhibit genes mediating iron acquisition during iron excess by facilitating the deposition of histone variant H2A.Z and histone 3 lysine 27 trimethylation (H3K27 me3) at the first nucleosome after the transcription start site. In addition, the monothiol glutaredoxin FgGrx4 is responsible for iron sensing and control of the transcriptional activity of FgHapX and FgSreA via modulation of their enrichment at target genes and recruitment of epigenetic regulators, respectively. Taken together, our findings elucidated the molecular mechanisms for adaptation to iron excess mediated by FgHapX and FgSreA during infection in F. graminearum and provide novel insights into regulation of iron homeostasis at the chromatin level in eukaryotes.
Topics: Chromatin; Histones; Iron; Nucleosomes; Siderophores; Fusarium
PubMed: 37650633
DOI: 10.1093/nar/gkad708 -
The Biochemical Journal Aug 2023OTUD1 (Ovarian tumor domain-containing deubiquitinase 1) is a member of the OTU domain-containing deubiquitinase family of enzymes involved in immunoregulation and...
OTUD1 (Ovarian tumor domain-containing deubiquitinase 1) is a member of the OTU domain-containing deubiquitinase family of enzymes involved in immunoregulation and tumorigenesis pathways. OTUD1 consists of three distinct regions: an unstructured N-terminal region, an OTU-fold catalytic domain, and a ubiquitin-interacting motif (UIM) containing region. Enhanced enzymatic activity and a strong preference for K63-linked substrates are imparted by the UIM containing region. We used phage display with a ubiquitin variant (UbV) library to identify binders for OTUD1 lacking the unstructured N-terminal region (OTUD1OTU + UIM) in an attempt to identify inhibitors bridging the catalytic domain and the UIM containing region. Two UbVs were identified (UbVOD.1 and UbVOD.2) with high affinity and specificity for OTUD1. Of the UbVs identified, UbVOD.1 inhibited OTUD1 activity towards mono-Ub and K63-linked di-Ub substrates in vitro with single-digit nanomolar IC50 and potently inhibited deubiquitinase activity with poly-Ub chains of other linkages. In vivo expression of UbVOD.1 alone was unstable, however as a di-UbV, global deubiquitination and deubiquitinase activity with the OTUD1 substrate RIPK1 were inhibited. Herein we describe the development of molecular tools for exploring the activity of OTUD1 in a cellular context, towards protein-based therapeutics.
Topics: Humans; Carcinogenesis; Catalytic Domain; Deubiquitinating Enzymes; Ubiquitin; Ubiquitin-Specific Proteases
PubMed: 37589489
DOI: 10.1042/BCJ20230119 -
Expert Reviews in Molecular Medicine Mar 2024Deubiquitinases are a group of proteins that identify and digest monoubiquitin chains or polyubiquitin chains attached to substrate proteins, preventing the substrate... (Review)
Review
Deubiquitinases are a group of proteins that identify and digest monoubiquitin chains or polyubiquitin chains attached to substrate proteins, preventing the substrate protein from being degraded by the ubiquitin-proteasome system. Deubiquitinases regulate cellular autophagy, metabolism and oxidative stress by acting on different substrate proteins. Recent studies have revealed that deubiquitinases act as a critical regulator in various cardiac diseases, and control the onset and progression of cardiac disease through a board range of mechanism. This review summarizes the function of different deubiquitinases in cardiac disease, including cardiac hypertrophy, myocardial infarction and diabetes mellitus-related cardiac disease. Besides, this review briefly recapitulates the role of deubiquitinases modulators in cardiac disease, providing the potential therapeutic targets in the future.
Topics: Humans; Ubiquitin; Polyubiquitin; Proteasome Endopeptidase Complex; Myocardial Infarction; Deubiquitinating Enzymes
PubMed: 38525836
DOI: 10.1017/erm.2024.2 -
Cell Death & Disease Aug 2023Ubiquitination is a reversible process that not only controls protein synthesis and degradation, but also is essential for protein transport, localization and biological...
Ubiquitination is a reversible process that not only controls protein synthesis and degradation, but also is essential for protein transport, localization and biological activity. Deubiquitinating enzyme (DUB) dysfunction leads to various diseases, including cancer. In this study, we aimed to explore the functions and mechanisms of crucial DUBs in head and neck squamous cell carcinoma (HNSCC). Based on bioinformatic analysis and immunohistochemistry detection, YOD1 was identified to be significantly downregulated in HNSCC specimens compared with adjacent normal tissues. Further analysis revealed that reduced YOD1 expression was associated with the malignant progression of HNSCC and indicated poor prognosis. The results of the in vitro and in vivo experiments verified that YOD1 depletion significantly promoted growth, invasion, and epithelial-mesenchymal transition in HNSCC. Mechanistically, YOD1 inhibited the activation of the ERK/β-catenin pathway by suppressing the ubiquitination and degradation of TRIM33, leading to the constriction of HNSCC progression. Overall, our findings reveal the molecular mechanism underlying the role of YOD1 in tumor progression and provide a novel potential therapeutic target for HNSCC treatment.
Topics: Humans; Squamous Cell Carcinoma of Head and Neck; Ubiquitin-Protein Ligases; Head and Neck Neoplasms; Ubiquitination; Deubiquitinating Enzymes; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Epithelial-Mesenchymal Transition; Transcription Factors; Endopeptidases; Thiolester Hydrolases
PubMed: 37573347
DOI: 10.1038/s41419-023-06035-0 -
Advanced Science (Weinheim,... Mar 2024Various forms of programmed cell death (PCD) exhibit distinct characteristics depending on their specific molecular mechanisms, and there are interactions among these...
Various forms of programmed cell death (PCD) exhibit distinct characteristics depending on their specific molecular mechanisms, and there are interactions among these different forms. Ferroptosis, which is related to autophagy and apoptosis, has an unknown potential interaction with pyroptosis. This study revealed a mutually antagonistic relationship between ferroptosis and pyroptosis, with 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) playing a key role in their interaction. It is found that HMGCR predominantly localized to mitochondria during ferroptosis but shifted to the endoplasmic reticulum following treatment with a pyroptosis inducer. Furthermore, this study demonstrated that BRCC36 (BRCA1/BRCA2-containing complex subunit 36) deubiquitinated HMGCR in a manner dependent on deubiquitinating enzyme (DUB) activity, and inhibited ferroptosis and promoted pyroptosis. Moreover, as an oncogene in hepatocellular carcinoma (HCC), BRCC36 promoted cancer cell proliferation, migration, invasion, and tumor growth. Thiolutin, an inhibitor of BRCC36, effectively suppressed the interaction between BRCC36 and HMGCR, leading to the inhibition of HCC growth. Therefore, targeting BRCC36 can offer a novel and promising therapeutic strategy for HCC treatment. In conclusion, these findings provide new theoretical evidence for further characterizing tumor heterogeneity and offer new molecular targets for the diagnosis and treatment of HCC.
Topics: Humans; Pyroptosis; Carcinoma, Hepatocellular; Oxidoreductases; Ferroptosis; Liver Neoplasms; Hydroxymethylglutaryl CoA Reductases
PubMed: 38178583
DOI: 10.1002/advs.202304263 -
Cancer Letters Jul 2024Ubiquitination and related cellular processes control a variety of aspects in human cell biology, and defects in these processes contribute to multiple illnesses. In... (Review)
Review
Ubiquitination and related cellular processes control a variety of aspects in human cell biology, and defects in these processes contribute to multiple illnesses. In recent decades, our knowledge about the pathological role of ubiquitination in lymphoid cancers and therapeutic strategies to target the modified ubiquitination system has evolved tremendously. Here we review the altered signalling mechanisms mediated by the aberrant expression of cancer-associated E2s/E3s and deubiquitinating enzymes (DUBs), which result in the hyperactivation of oncoproteins or the frequently allied downregulation of tumour suppressors. We discuss recent highlights pertaining to the several different therapeutic interventions which are currently being evaluated to effectively block abnormal ubiquitin-proteasome pathway and the use of heterobifunctional molecules which recruit the ubiquitination system to degrade or stabilize non-cognate substrates. This review aids in comprehension of ubiquitination aberrance in lymphoid cancers and current targeting strategies and elicits further investigations to deeply understand the link between cellular ubiquitination and lymphoid pathogenesis as well as to ameliorate corresponding treatment interventions.
Topics: Humans; Ubiquitination; Signal Transduction; Ubiquitin; Animals; Lymphoma; Molecular Targeted Therapy; Antineoplastic Agents; Proteasome Endopeptidase Complex; Deubiquitinating Enzymes
PubMed: 38795760
DOI: 10.1016/j.canlet.2024.216978