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Oncology Reports Oct 2023The ubiquitin‑proteasome system is a major degradation pathway for >80% of proteins . Deubiquitylases, which remove ubiquitinated tags to stabilize substrate proteins,... (Review)
Review
The ubiquitin‑proteasome system is a major degradation pathway for >80% of proteins . Deubiquitylases, which remove ubiquitinated tags to stabilize substrate proteins, are important components involved in regulating the degradation of ubiquitinated proteins. In addition, they serve multiple roles in tumor development by participating in physiological processes such as protein metabolism, cell cycle regulation, DNA damage repair and gene transcription. The present review systematically summarized the role of ubiquitin‑specific protease 2 (USP2) in malignant tumors and the specific molecular mechanisms underlying the involvement of in tumor‑associated pathways. reverses ubiquitin‑mediated degradation of proteins and is involved in aberrant proliferation, migration, invasion, apoptosis and drug resistance of tumors. Additionally, the present review summarized studies reporting on the use of as a therapeutic target for malignancies such as breast, liver, ovarian, colorectal, bladder and prostate cancers and glioblastoma and highlights the current status of pharmacological research on . The clinical significance of as a therapeutic target for malignant tumors warrants further investigation.
Topics: Humans; Apoptosis; Deubiquitinating Enzymes; Glioblastoma; Ubiquitin; Ubiquitin Thiolesterase
PubMed: 37594087
DOI: 10.3892/or.2023.8613 -
The Journal of Biological Chemistry Nov 2023Ubiquitin-specific proteases (USPs) are crucial for controlling cellular proteostasis and signaling pathways but how deubiquitination is selective remains poorly...
Ubiquitin-specific proteases (USPs) are crucial for controlling cellular proteostasis and signaling pathways but how deubiquitination is selective remains poorly understood, in particular between paralogues. Here, we developed a fusion tag method by mining the Protein Data Bank and trapped USP11, a key regulator of DNA double-strand break repair, in complex with a novel engineered substrate mimetic. Together, this enabled structure determination of USP11 as a Michaelis-like complex that revealed key S1 and S1' binding site interactions with a substrate. Combined mutational, enzymatic, and binding experiments identified Met in linear diubiquitin as a significant residue that leads to substrate discrimination. We identified an aspartate "gatekeeper" residue in the S1' site of USP11 as a contributing feature for discriminating against linear diubiquitin. When mutated to a glycine, the corresponding residue in paralog USP15, USP11 acquired elevated activity toward linear diubiquitin in-gel shift assays, but not controls. The reverse mutation in USP15 confirmed that this position confers paralog-specific differences impacting diubiquitin cleavage rates. The results advance our understanding of the molecular basis for the higher selectivity of USP11 compared to USP15 and may aid targeted inhibitor development. Moreover, the reported carrier-based crystallization strategy may be applicable to other challenging targets.
Topics: Binding Sites; Ubiquitin-Specific Proteases; Humans; Ubiquitination; Models, Molecular; Protein Structure, Tertiary; Crystallography, X-Ray; Substrate Specificity
PubMed: 37777157
DOI: 10.1016/j.jbc.2023.105300 -
Clinical and Translational Medicine Dec 2023Abelson tyrosine kinase (c-Abl) is frequently mutated and highly expressed, and promotes non-small-cell lung cancer (NSCLC) survival, metastasis and tumorigenesis. c-Abl...
BACKGROUND
Abelson tyrosine kinase (c-Abl) is frequently mutated and highly expressed, and promotes non-small-cell lung cancer (NSCLC) survival, metastasis and tumorigenesis. c-Abl could also be modified through ubiquitination, but the underlying mechanism is not well understood.
METHODS
Mass spectrometry assays were performed to search c-Abl deubiquitination enzymes. The molecular mechanism was determined using Co-IP assays, pull-down assays, Western blotting upon gene knockdown or overexpression. Cell lines and animal models were used to investigate the role of c-Abl and USP7 in NSCLC. EdU staining assay and Transwell assay were performed to evaluate the proliferation and migration ability of NSCLC cells, respectively.
RESULTS
Ubiquitin-specific protease 7 (USP7) is found to upregulate c-Abl via the deubiquitinase screen. USP7 interacts with c-Abl and decreases its K48-linked polyubiquitination, thereby increasing the stability of c-Abl. In addition to the wild-type one, c-Abl mutants can also be deubiquitinated and stabilized by USP7. Moreover, USP7 promotes c-Abl accumulation in cytoplasm by increasing its binding to 14-3-3α/β and activates the oncogenic c-Abl signalling pathway. Furthermore, the USP7/c-Abl axis promotes NSCLC cell glycolysis by direct phosphorylating and stabilizing hexokinase-2 (HK2). Knockdown of USP7 or c-Abl suppresses NSCLC cell glycolysis and reduces lactate production. Further studies revealed that overexpression of USP7 facilitates NSCLC cell growth and metastasis as well as xenograft growth in nude mice, while these activities are suppressed with USP7 or c-Abl being knocked down.
CONCLUSIONS
USP7 is a deubiquitinase of c-Abl and upregulates its oncogenic activity. USP7 promotes NSCLC cell metabolism by activating c-Abl and HK2. Targeting the USP7/c-Abl/HK2 axis might be a potential strategy to the precision therapy of NSCLC.
Topics: Animals; Mice; Humans; Carcinoma, Non-Small-Cell Lung; Lung Neoplasms; Ubiquitin-Specific Peptidase 7; Mice, Nude; Glycolysis
PubMed: 38082439
DOI: 10.1002/ctm2.1509 -
Cell Death & Disease Jul 2023The cytokine tumor necrosis factor (TNF) critically regulates the intertwined cell death and pro-inflammatory signaling pathways of dendritic cells (DCs) via ubiquitin...
The cytokine tumor necrosis factor (TNF) critically regulates the intertwined cell death and pro-inflammatory signaling pathways of dendritic cells (DCs) via ubiquitin modification of central effector molecules, but the intrinsic molecular switches deciding on either pathway are incompletely defined. Here, we uncover that the ovarian tumor deubiquitinating enzyme 7b (OTUD7b) prevents TNF-induced apoptosis of DCs in infection, resulting in efficient priming of pathogen-specific CD8 T cells. Mechanistically, OTUD7b stabilizes the E3 ligase TNF-receptor-associated factor 2 (TRAF2) in human and murine DCs by counteracting its K48-ubiquitination and proteasomal degradation. TRAF2 in turn facilitates K63-linked polyubiquitination of RIPK1, which mediates activation of NF-κB and MAP kinases, IL-12 production, and expression of anti-apoptotic cFLIP and Bcl-xL. We show that mice with DC-specific OTUD7b-deficiency displayed DC apoptosis and a failure to induce CD8 T cell-mediated brain pathology, experimental cerebral malaria, in a murine malaria infection model. Together, our data identify the deubiquitinating enzyme OTUD7b as a central molecular switch deciding on survival of human and murine DCs and provides a rationale to manipulate DC responses by targeting their ubiquitin network downstream of the TNF receptor pathway.
Topics: Animals; Humans; Mice; Apoptosis; CD8-Positive T-Lymphocytes; Dendritic Cells; Deubiquitinating Enzymes; TNF Receptor-Associated Factor 2; Tumor Necrosis Factor-alpha; Ubiquitin-Protein Ligases; Ubiquitins
PubMed: 37516734
DOI: 10.1038/s41419-023-06014-5 -
Frontiers in Molecular Biosciences 2023Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignant tumor of the digestive system, characterized by rapid progression and being prone to metastasis. Few... (Review)
Review
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignant tumor of the digestive system, characterized by rapid progression and being prone to metastasis. Few effective treatment options are available for PDAC, and its 5-year survival rate is less than 9%. Many cell biological and signaling events are involved in the development of PDAC, among which protein post-translational modifications (PTMs), such as ubiquitination, play crucial roles. Catalyzed mostly by a three-enzyme cascade, ubiquitination induces changes in protein activity mainly by altering their stability in PDAC. Due to their role in substrate recognition, E3 ubiquitin ligases (E3s) dictate the outcome of the modification. Ubiquitination can be reversed by deubiquitylases (DUBs), which, in return, modified proteins to their native form. Dysregulation of E3s or DUBs that disrupt protein homeostasis is involved in PDAC. Moreover, the ubiquitination system has been exploited to develop therapeutic strategies, such as proteolysis-targeting chimeras (PROTACs). In this review, we summarize recent progress in our understanding of the role of ubiquitination in the development of PDAC and offer perspectives in the design of new therapies against this highly challenging disease.
PubMed: 38174069
DOI: 10.3389/fmolb.2023.1304639 -
Molecular Cancer Research : MCR Dec 2023Lysine-specific demethylase 1 (LSD1), a critical chromatin modulator, functions as an oncogene by demethylation of H3K4me1/2. The stability of LSD1 is governed by a...
UNLABELLED
Lysine-specific demethylase 1 (LSD1), a critical chromatin modulator, functions as an oncogene by demethylation of H3K4me1/2. The stability of LSD1 is governed by a complex and intricate process involving ubiquitination and deubiquitination. Several deubiquitinases preserve LSD1 protein levels. However, the precise mechanism underlying the degradation of LSD1, which could mitigate its oncogenic function, remains unknown. To gain a better understanding of LSD1 degradation, we conducted an unbiased siRNA screening targeting all the human SCF family E3 ligases. Our screening identified FBXO24 as a genuine E3 ligase that ubiquitinates and degrades LSD1. As a result, FBXO24 inhibits LSD1-induced tumorigenesis and functions as a tumor suppressor in breast cancer cells. Moreover, FBXO24 exhibits an inverse correlation with LSD1 and is associated with a favorable prognosis in breast cancer patient samples. Taken together, our study uncovers the significant role of FBXO24 in impeding breast tumor progression by targeting LSD1 for degradation.
IMPLICATIONS
Our study provides comprehensive characterization of the significant role of FBXO24 in impeding breast tumor progression by targeting LSD1 for degradation.
Topics: Female; Humans; Breast Neoplasms; Carcinogenesis; Cell Line, Tumor; Cell Transformation, Neoplastic; Histone Demethylases; Ubiquitin-Protein Ligases; Ubiquitination
PubMed: 37540490
DOI: 10.1158/1541-7786.MCR-23-0169 -
The Journal of Cell Biology Feb 2024Metastasis is the main cause of colorectal cancer (CRC)-related death, and the 5-year relative survival rate for CRC patients with distant metastasis is only 14%....
Metastasis is the main cause of colorectal cancer (CRC)-related death, and the 5-year relative survival rate for CRC patients with distant metastasis is only 14%. X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1) is a zinc-rich protein belonging to the interferon (IFN)-induced gene family. Here, we report a metastasis-promoting role of XAF1 in CRC by acting as a novel adaptor of valosin-containing protein (VCP). XAF1 facilitates VCP-mediated deubiquitination of the E3 ligase RING finger protein 114 (RNF114), which promotes K48-linked ubiquitination and subsequent degradation of junction plakoglobin (JUP). The XAF1-VCP-RNF114-JUP axis is critical for the migration and metastasis of CRC cells. Moreover, we observe correlations between the protein levels of XAF1, RNF114, and JUP in clinical samples. Collectively, our findings reveal an oncogenic function of XAF1 in mCRC and suggest that the XAF1-VCP-RNF114-JUP axis is a potential therapeutic target for CRC treatment.
Topics: Humans; Adaptor Proteins, Signal Transducing; Apoptosis; Apoptosis Regulatory Proteins; Colorectal Neoplasms; gamma Catenin; Intracellular Signaling Peptides and Proteins; Neoplasm Proteins; Valosin Containing Protein
PubMed: 38095639
DOI: 10.1083/jcb.202303015 -
MBio Aug 2023The histone acetyltransferase general control non-depressible 5 (Gcn5) plays a critical role in the epigenetic landscape and chromatin modification for regulating a wide...
The histone acetyltransferase general control non-depressible 5 (Gcn5) plays a critical role in the epigenetic landscape and chromatin modification for regulating a wide variety of biological events. However, the post-translational regulation of Gcn5 itself is poorly understood. Here, we found that Gcn5 was ubiquitinated and deubiquitinated by E3 ligase Tom1 and deubiquitinating enzyme Ubp14, respectively, in the important plant pathogenic fungus . Tom1 interacted with Gcn5 in the nucleus and subsequently ubiquitinated Gcn5 mainly at K252 to accelerate protein degradation. Conversely, Ubp14 deubiquitinated Gcn5 and enhanced its stability. In the deletion mutant Δ, protein level of Gcn5 was significantly reduced and resulted in attenuated virulence in the fungus by affecting the mycotoxin production, autophagy process, and the penetration ability. Our findings indicate that Tom1 and Ubp14 show antagonistic functions in the control of the protein stability of Gcn5 via post-translational modification and highlight the importance of Tom1-Gcn5-Ubp14 circuit in the fungal virulence. IMPORTANCE Post-translational modification (PTM) enzymes have been reported to be involved in regulating numerous cellular processes. However, the modification of these PTM enzymes themselves is largely unknown. In this study, we found that the E3 ligase Tom1 and deubiquitinating enzyme Ubp14 contributed to the regulation of ubiquitination and deubiquitination of acetyltransferase Gcn5, respectively, in , the causal agent of Fusarium head blight of cereals. Our findings provide deep insights into the modification of acetyltransferase Gcn5 and its dynamic regulation via ubiquitination and deubiquitination. To our knowledge, this work is the most comprehensive analysis of a regulatory network of ubiquitination that impinges on acetyltransferase in filamentous pathogens. Moreover, our findings are important because we present the novel roles of the Tom1-Gcn5-Ubp14 circuit in fungal virulence, providing novel possibilities and targets to control fungal diseases.
Topics: Fusarium; Virulence; Ubiquitination; Histone Acetyltransferases; Ubiquitin-Protein Ligases; Deubiquitinating Enzymes; Fungal Proteins; Plant Diseases; Spores, Fungal
PubMed: 37504517
DOI: 10.1128/mbio.01499-23 -
Journal of Experimental & Clinical... Sep 2023Tumors have evolved in various mechanisms to evade the immune system, hindering the antitumor immune response and facilitating tumor progression. Immunotherapy has... (Review)
Review
Tumors have evolved in various mechanisms to evade the immune system, hindering the antitumor immune response and facilitating tumor progression. Immunotherapy has become a potential treatment strategy specific to different cancer types by utilizing multifarious molecular mechanisms to enhance the immune response against tumors. Among these mechanisms, the ubiquitin-proteasome system (UPS) is a significant non-lysosomal pathway specific to protein degradation, regulated by deubiquitinating enzymes (DUBs) that counterbalance ubiquitin signaling. Ubiquitin-specific proteases (USPs), the largest DUB family with the strongest variety, play critical roles in modulating immune cell function, regulating immune response, and participating in antigen processing and presentation during tumor progression. According to recent studies, the expressions of some USP family members in tumor cells are involved in tumor immune escape and immune microenvironment. This review explores the potential of targeting USPs as a new approach for cancer immunotherapy, highlighting recent basic and preclinical studies investigating the applications of USP inhibitors. By providing insights into the structure and function of USPs in cancer immunity, this review aims at assisting in developing new therapeutic approaches for enhancing the immunotherapy efficacy.
Topics: Humans; Immunotherapy; Cytoplasm; Proteasome Endopeptidase Complex; Ubiquitin; Ubiquitin-Specific Proteases; Neoplasms
PubMed: 37658402
DOI: 10.1186/s13046-023-02805-y -
Frontiers in Bioscience (Landmark... Feb 2024The mitochondrial antiviral-signaling protein (MAVS), a core adaptor protein in the retinoic-acid-inducible gene-I-like receptors (RLRs)-MAVS pathway, has been... (Review)
Review
The mitochondrial antiviral-signaling protein (MAVS), a core adaptor protein in the retinoic-acid-inducible gene-I-like receptors (RLRs)-MAVS pathway, has been demonstrated to play an important role in antiviral immune response and tumor immunology. Previous studies revealed that ubiquitylation is a key mechanism in the regulation of the RLRs-MAVS axis and immune response. Multiple E3 ubiquitin ligases and deubiquitinating enzymes control MAVS ubiquitylation and changes in MAVS function. In this review, we summarize the biological function of ubiquitylation in MAVS-related signaling and provide new insight into immunotherapy approaches that target MAVS.
Topics: Ubiquitination; Signal Transduction; Ubiquitin-Protein Ligases; Carrier Proteins
PubMed: 38420830
DOI: 10.31083/j.fbl2902072