المؤلفون: Peng Zhang, Ze Hong, Juanjuan Zhu, Jin-fu Xu, Haiyang Hu, Ye Cui, Huansha Yu, Dong Qian, Chenhui Li, Quanyi Wang, Chen Wang, Lele Zhang, Mingxing Cheng, Wei Meng, Yi Sun

المصدر: PLoS Pathogens
PLoS Pathogens, Vol 17, Iss 3, p e1009401 (2021)

مصطلحات موضوعية: Small interfering RNA, NEDD8, Biochemistry, Physical Chemistry, Mice, 0302 clinical medicine, Interferon, Medicine and Health Sciences, Biology (General), Enzyme-Linked Immunoassays, Post-Translational Modification, Phosphorylation, Immune Response, 0303 health sciences, biology, Chemistry, Nucleotidyltransferases, Cell biology, Ubiquitin ligase, Precipitation Techniques, Nucleic acids, Virus Diseases, 030220 oncology & carcinogenesis, Physical Sciences, Dimerization, Signal Transduction, medicine.drug, Research Article, QH301-705.5, Ubiquitin-Protein Ligases, Immunology, Research and Analysis Methods, Transfection, Microbiology, Proinflammatory cytokine, 03 medical and health sciences, Immune Deficiency, Immune system, Virology, medicine, Genetics, Animals, Humans, Immunoprecipitation, Molecular Biology Techniques, Non-coding RNA, Immunoassays, Molecular Biology, 030304 developmental biology, Innate immune system, Biology and life sciences, Correction, Proteins, RC581-607, Immunity, Innate, Gene regulation, Chemical Properties, Ubiquitin-Conjugating Enzymes, biology.protein, Immunologic Techniques, RNA, Parasitology, Clinical Immunology, Neddylation, Gene expression, Immunologic diseases. Allergy, Clinical Medicine, Protein Processing, Post-Translational

الوصف: The cytosolic DNA sensor cyclic GMP-AMP (cGAMP) synthetase (cGAS) has emerged as a fundamental component fueling the anti-pathogen immunity. Because of its pivotal role in initiating innate immune response, the activity of cGAS must be tightly fine-tuned to maintain immune homeostasis in antiviral response. Here, we reported that neddylation modification was indispensable for appropriate cGAS-STING signaling activation. Blocking neddylation pathway using neddylation inhibitor MLN4924 substantially impaired the induction of type I interferon and proinflammatory cytokines, which was selectively dependent on Nedd8 E2 enzyme Ube2m. We further found that deficiency of the Nedd8 E3 ligase Rnf111 greatly attenuated DNA-triggered cGAS activation while not affecting cGAMP induced activation of STING, demonstrating that Rnf111 was the Nedd8 E3 ligase of cGAS. By performing mass spectrometry, we identified Lys231 and Lys421 as essential neddylation sites in human cGAS. Mechanistically, Rnf111 interacted with and polyneddylated cGAS, which in turn promoted its dimerization and enhanced the DNA-binding ability, leading to proper cGAS-STING pathway activation. In the same line, the Ube2m or Rnf111 deficiency mice exhibited severe defects in innate immune response and were susceptible to HSV-1 infection. Collectively, our study uncovered a vital role of the Ube2m-Rnf111 neddylation axis in promoting the activity of the cGAS-STING pathway and highlighted the importance of neddylation modification in antiviral defense.
Author summary The Cyclic GMP-AMP (cGAMP) synthase (cGAS) is a critical cytosolic DNA sensor by monitoring pathogens-derived DNA, while its aberrant activation leads to tissue damage. Thus, the activity of cGAS must be tightly regulated to keep immune homeostasis. Several post-translational modifications have been demonstrated to be important in fine-tuning activities of cGAS. However, the mechanism underlying how cGAS is precisely regulated remains not fully understood. In this study, we uncovered that cGAS was poly-neddylated by the Ube2m-Rnf111 axis, and the poly-NEDD8 chains played a role as nexus in linking the second cGAS, leading to the appropriate dimerization and the subsequent activation of cGAS. Our study revealed a novel and critical role of neddylation in the regulation of the cGAS-STING signaling pathway and provided a new perspective for restricting the infection of DNA pathogens.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::77e6a950e4c316465b673dd95d5d4ef4Test
http://europepmc.org/articles/PMC7959372Test

المؤلفون: Yongchao Zhao, Yi Sun, Xiufang Xiong

المصدر: Seminars in cancer biology. 67(Pt 2)

مصطلحات موضوعية: 0301 basic medicine, Cancer Research, Ubiquitin-Protein Ligases, Inflammation, Suppressor of Cytokine Signaling Proteins, medicine.disease_cause, Antiviral Agents, law.invention, 03 medical and health sciences, Viral Proteins, 0302 clinical medicine, law, Neoplasms, medicine, Humans, Molecular Targeted Therapy, Receptor, chemistry.chemical_classification, DNA ligase, biology, Signal transducing adaptor protein, Cullin Proteins, Cell biology, 030104 developmental biology, chemistry, 030220 oncology & carcinogenesis, Multiprotein Complexes, biology.protein, Suppressor, medicine.symptom, Carcinogenesis, Carrier Proteins, CUL5, Cullin

الوصف: Cullin-RING ligase 5 (CRL5) is a multi-protein complex and consists of a scaffold protien cullin 5, a RING protein RBX2 (also known as ROC2 or SAG), adaptor proteins Elongin B/C, and a substrate receptor protein SOCS. Through targeting a variety of substrates for proteasomal degradation or modulating various protein-protein interactions, CRL5 is involved in regulation of many biological processes, such as cytokine signal transduction, inflammation, viral infection, and oncogenesis. As many substrates of CRL5 are well-known oncoproteins or tumor suppressors, abnormal regulation of CRL5 is commonly found in human cancers. In this review, we first briefly introduce each of CRL5 components, and then discuss the biological processes regulated by four members of SOCS-box-containing substrate receptor family through substrate degradation. We next describe how CRL5 is hijacked by a variety of viral proteins to degrade host anti-viral proteins, which facilitates virus infection. We further discuss the regulation of CUL5 and its various roles in human cancers, acting as either a tumor suppressor or an oncoprotein in a context-dependent manner. Finally, we propose novel insights for future perspectives on the validation of cullin5 and other CRL5 components as potential targets, and possible targeting strategies to discover CRL5 inhibitors for anti-cancer and anti-virus therapies.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::44dc5e9be5156892fbec4bb6fe97b779Test
https://pubmed.ncbi.nlm.nih.gov/32334051Test

المؤلفون: Lisha Zhou, Wenjuan Zhang, Lijun Jia, Yi Sun

المصدر: Cellular Signalling. 44:92-102

مصطلحات موضوعية: 0301 basic medicine, Ubiquitin-Protein Ligases, Apoptosis, Context (language use), Cyclopentanes, Ubiquitin-Activating Enzymes, NEDD8, Article, 03 medical and health sciences, Protein neddylation, Ubiquitin, Neoplasms, Autophagy, Humans, Molecular Targeted Therapy, Cellular Senescence, biology, Chemistry, Cell Cycle Checkpoints, Cell Biology, Cell biology, Pyrimidines, 030104 developmental biology, Pevonedistat, biology.protein, Neddylation, Protein Processing, Post-Translational, Cullin

الوصف: Neddylation, a post-translational modification that conjugates an ubiquitin-like protein NEDD8 to substrate proteins, is an important biochemical process that regulates protein function. The best-characterized substrates of neddylation are the cullin subunits of Cullin-RING ligases (CRLs), which, as the largest family of E3 ubiquitin ligases, control many important biological processes, including tumorigenesis, through promoting ubiquitylation and subsequent degradation of a variety of key regulatory proteins. Recently, increasing pieces of experimental evidence strongly indicate that the process of protein neddylation modification is elevated in multiple human cancers, providing sound rationale for its targeting as an attractive anticancer therapeutic strategy. Indeed, neddylation inactivation by MLN4924 (also known as pevonedistat), a small molecule inhibitor of E1 NEDD8-activating enzyme currently in phase I/II clinical trials, exerts significant anticancer effects by inducing cell cycle arrest, apoptosis, senescence and autophagy in a cell-type and context dependent manner. Here, we summarize the latest progresses in the field with a major focus on preclinical studies in validation of neddylation modification as a promising anticancer target.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d5766eec66ed495e4ef7ed07e4c89182Test
https://doi.org/10.1016/j.cellsig.2018.01.009Test

المؤلفون: Weihua Zhou, Haomin Li, Zhijian J. Chen, Jie Xu, Wenyi Wei, Zhen-Qiang Pan, Yi Sun, Ming Xu

المصدر: Clinical Cancer Research. 23:1104-1116

مصطلحات موضوعية: 0301 basic medicine, Cancer Research, Lung Neoplasms, Cell Survival, Ubiquitin-Protein Ligases, Apoptosis, Article, Mice, 03 medical and health sciences, Protein neddylation, Ubiquitin, Cell Line, Tumor, hemic and lymphatic diseases, medicine, Animals, Humans, Gene silencing, Cell Proliferation, Gene knockdown, biology, Cell growth, Ubiquitination, Cancer, medicine.disease, Xenograft Model Antitumor Assays, Cell biology, Gene Expression Regulation, Neoplastic, 030104 developmental biology, Proto-Oncogene Proteins c-bcl-2, Oncology, Proteolysis, Ubiquitin-Conjugating Enzymes, biology.protein, Neddylation, Signal transduction, Signal Transduction

الوصف: Purpose: Recent studies have shown that the process of protein neddylation was abnormally activated in several human cancers. However, it is unknown whether and how UBE2F, a less characterized neddylation E2, regulates lung cancer cell survival, and whether and how NOXA, a proapoptotic protein, is ubiquitylated and degraded by which E3 and via which ubiquitin linkage. Experimental Design: Methods of immunohistochemistry and immunoblotting were utilized to examine UBE2F protein expression. The biological functions of UBE2F were evaluated by in vitro cell culture and in vivo xenograft models. The in vivo complex formation among UBE2F-SAG-CUL5-NOXA was measured by a pulldown assay. Polyubiquitylation of NOXA was evaluated by in vivo and in vitro ubiquitylation assays. Results: UBE2F is overexpressed in non–small cell lung cancer (NSCLC) and predicts poor patient survival. While UBE2F overexpression promotes lung cancer growth both in vitro and in vivo, UBE2F knockdown selectively inhibits tumor growth. By promoting CUL5 neddylation, UBE2F/SAG/CUL5 tri-complex activates CRL5 (Cullin-RING-ligase-5) to ubiquitylate NOXA via a novel K11, but not K48, linkage for targeted proteasomal degradation. CRL5 inactivation or forced expression of K11R ubiquitin mutant caused NOXA accumulation to induce apoptosis, which is rescued by NOXA knockdown. Notably, NOXA knockdown rescues the UBE2F silencing effect, indicating a causal role of NOXA in this process. In lung cancer tissues, high levels of UBE2F and CUL5 correlate with a low level of NOXA and poor patient survival. Conclusions: By ubiquitylating and degrading NOXA through activating CRL5, UBE2F selectively promotes lung cancer cell survival and could, therefore, serve as a novel cancer target. Clin Cancer Res; 23(4); 1104–16. ©2016 AACR.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fdae9f54939fba66306bdfd04abc746dTest
https://doi.org/10.1158/1078-0432.ccr-16-1585Test

المؤلفون: Xiufang Xiong, Nathan D. Mathewson, Hua Li, Mingjia Tan, Hideaki Fujiwara, Haomin Li, Pavan Reddy, Yi Sun

المصدر: Frontiers in Immunology, Vol 9 (2018)
Frontiers in Immunology

مصطلحات موضوعية: 0301 basic medicine, Lipopolysaccharides, Male, Myeloid, Neutrophils, SAG ubiquitin ligase, Mice, 0302 clinical medicine, Immunology and Allergy, Macrophage, Cells, Cultured, Escherichia coli Infections, Original Research, Mice, Knockout, biology, Chemistry, Elastase, neutrophil, Cell Differentiation, inflammatory response, Ubiquitin ligase, Cell biology, medicine.anatomical_structure, 030220 oncology & carcinogenesis, Myeloperoxidase, Cytokines, Female, lcsh:Immunologic diseases. Allergy, LPS, Ubiquitin-Protein Ligases, Immunology, Primary Cell Culture, macrophage, Proinflammatory cytokine, 03 medical and health sciences, parasitic diseases, medicine, Escherichia coli, Animals, Humans, Myeloid Progenitor Cells, Peroxidase, Innate immune system, Macrophages, Disease Models, Animal, 030104 developmental biology, Apoptosis, biology.protein, Leukocyte Elastase, lcsh:RC581-607

الوصف: Macrophages form an important component of the innate immune system and serve as first responders against invading pathogens. While pathways critical for initiation of inflammatory responses between macrophages and other LysM+ myeloid cells are largely similar, it remains unknown whether a specific pathway has differential effects on inflammatory responses mediated between these cells. Recent studies demonstrated that depletion of SAG (Sensitive to Apoptosis Gene), an E3 ubiquitin ligase, blocked inflammatory responses generated by macrophages and dendritic cells in response to LPS in cell culture settings. However, the in vivo role of Sag on modulation of macrophages and neutrophil is not known. Here we generated LysM-Cre/Sagfl/fl mice with selective Sag deletion in myeloid lineage, and found that in contrast to in vitro observations, LysM-Cre/Sagfl/fl mice showed increased serum levels of proinflammatory cytokines and enhanced mortality in response to LPS. Interestingly, while Sag-/- macrophages released less proinflammatory cytokines, Sag-/- neutrophils released more. Mechanistically, expression of a list of genes response to LPS was significantly altered in bone marrow cells from LysM-Cre+/Sagfl/fl mice after LPS challenge. Specifically, induction by LPS of myeloperoxidase (Mpo), a key neutrophil enzyme, and Elane, neutrophil expressed elastase, was significantly decreased upon Sag depletion. Collectively, our study revealed that Sag plays a differential role in the activation of macrophages and neutrophils.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4e52e08ca92c4b7e3b9ffb3a61e2d2b0Test
https://www.frontiersin.org/article/10.3389/fimmu.2018.02882/fullTest

المؤلفون: Xiufang Xiong, Shizhen Zhang, Wenyi Wei, Chao Bi, Yanwen Shen, Yi Sun, Hua Li, Yilun Sun

المصدر: Cell reports

مصطلحات موضوعية: 0301 basic medicine, Ubiquitin-Protein Ligases, Mutant, Drug Resistance, Cell Cycle Proteins, chemical and pharmacologic phenomena, Endogeny, Drug resistance, Transfection, Article, Anaphase-Promoting Complex-Cyclosome, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, 0302 clinical medicine, Ubiquitin, parasitic diseases, Humans, Mitosis, Gene knockdown, biology, Chemistry, Cell cycle, Ubiquitin ligase, Cell biology, body regions, 030104 developmental biology, Disease Progression, biology.protein, 030217 neurology & neurosurgery

الوصف: SUMMARY Anaphase-promoting complex/cyclosome (APC/C) is a well-characterized E3 ligase that couples with UBE2C and UBE2S E2s for substrate ubiquitylation by the K11 linkage. Our recent data show that SAG/RBX2/ROC2, a RING component of Cullin-RING E3 ligase, also complexes with these E2s for K11-linked substrate polyubiquitylation. Whether these two E3s cross-talk with each other was previously unknown. Here, we report that SAG competes with APC2 for UBE2C/UBE2S binding to act as a potential endogenous inhibitor of APC/C, thereby regulating the G2-to-M progression. As such, SAG knockdown triggers premature activation of APC/C, leading to mitotic slippage and resistance to anti-microtubule drugs. On the other hand, SAG itself is a substrate of APC/CCDH1 for targeted degradation at the G1 phase. The degradation-resistant mutant of SAG-R98A/L101A accelerates the G1-to-S progression. Our study reveals that the negative cross-talk between SAG and APC/C is likely a mechanism to ensure the fidelity of cell cycle progression.
Graphical Abstract
In Brief Zhang et al. provide a mechanistic insight of how negative cross-talk between E3 ligases SAG and APC/C ensures proper cell cycle progression. SAG knockdown prematurely activates APC/C to promote mitotic progression and trigger anti-microtubule drugs resistance, whereas SAG degradation by APC/CCDH1 mainly occurs in G1 phase for proper G1-to-S transition.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9cd51b694133989f57126e2ea046726eTest
https://doi.org/10.1016/j.celrep.2020.108102Test

المؤلفون: Theodore S. Lawrence, David Karnak, Qiang Zhang, Yi Sun, Mingjia Tan, Meredith A. Morgan

المصدر: Molecular Cell. 61(3):419-433

مصطلحات موضوعية: 0301 basic medicine, Genome instability, Radiation-Sensitizing Agents, DNA End-Joining Repair, F-Box-WD Repeat-Containing Protein 7, Time Factors, Cell Cycle Proteins, Ataxia Telangiectasia Mutated Proteins, DNA-Activated Protein Kinase, Ubiquitin-Activating Enzymes, Radiation Tolerance, F-box protein, Ubiquitin, DNA Breaks, Double-Stranded, Enzyme Inhibitors, Phosphorylation, Polyubiquitin, Mice, Knockout, Genetics, Ku70, biology, Nuclear Proteins, DNA repair protein XRCC4, Ubiquitin ligase, Cell biology, DNA-Binding Proteins, Non-homologous end joining, RNA Interference, Ubiquitin-Protein Ligases, Molecular Sequence Data, Cyclopentanes, Transfection, Article, 03 medical and health sciences, Animals, Humans, Amino Acid Sequence, Ubiquitins, Molecular Biology, F-Box Proteins, Lysine, Ubiquitination, Cell Biology, HCT116 Cells, Pancreatic Neoplasms, enzymes and coenzymes (carbohydrates), Pyrimidines, 030104 developmental biology, biology.protein, Protein Processing, Post-Translational

الوصف: FBXW7 is a haploinsufficient tumor suppressor with loss-of-function mutations occurring in human cancers. FBXW7 inactivation causes genomic instability, but the mechanism remains elusive. Here we show that FBXW7 facilitates nonhomologous end-joining (NHEJ) repair and that FBXW7 depletion causes radiosensitization. In response to ionizing radiation, ATM phosphorylates FBXW7 at serine 26 to recruit it to DNA double-strand break (DSB) sites, whereas activated DNA-PKcs phosphorylates XRCC4 at serines 325/326, which promotes binding of XRCC4 to FBXW7. SCF(FBXW7) E3 ligase then promotes polyubiquitylation of XRCC4 at lysine 296 via lysine 63 linkage for enhanced association with the Ku70/80 complex to facilitate NHEJ repair. Consistent with these findings, a small-molecule inhibitor that abrogates XRCC4 polyubiquitylation reduces NHEJ repair. Our study demonstrates one mechanism by which FBXW7 contributes to genome integrity and implies that inactivated FBXW7 in human cancers could be a strategy for increasing the efficacy of radiotherapy.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7c414e00f54614840478df66fc34fb3fTest

المؤلفون: Hua Li, Wenyi Wei, Weihua Zhou, Jie Xu, Yi Sun, Haomin Li, Mingjia Tan

المصدر: Molecular cell. 70(6)

مصطلحات موضوعية: 0301 basic medicine, Ubiquitin-activating enzyme, Ubiquitin-Protein Ligases, Mice, Nude, Cyclopentanes, Ubiquitin-Activating Enzymes, Ubiquitin-conjugating enzyme, Biology, Article, Cell Line, 03 medical and health sciences, Mice, Ubiquitin, Stress, Physiological, Cell Line, Tumor, Animals, Humans, Molecular Biology, Ubiquitins, Mice, Inbred BALB C, Cullin Proteins, Ubiquitination, Cell Biology, KEAP1, Cell biology, 030104 developmental biology, HEK293 Cells, Pyrimidines, Ubiquitin-Conjugating Enzymes, biology.protein, Female, Neddylation, Cullin

الوصف: UBE2M and UBE2F are two family members of neddylation E2 conjugating enzyme that, together with E3s, activate CRLs (Cullin-RING Ligases) by catalyzing cullin neddylation. However, whether and how two E2s cross-talk with each other are largely unknown. Here, we report that UBE2M is a stress-inducible gene subjected to cis-transactivation by HIF-1α and AP1, and MLN4924, a small molecule inhibitor of E1 NEDD8-activating enzyme (NAE), up-regulates UBE2M via blocking degradation of HIF-1α and AP1. UBE2M is a dual E2 for targeted ubiquitylation and degradation of UBE2F, acting as a neddylation E2 to activate CUL3-Keap1 E3 under physiological condition, but as an ubiquitylation E2 for Parkin-DJ-1 E3 under stressed conditions. UBE2M-induced UBE2F degradation leads to CRL5 inactivation and subsequent NOXA accumulation to suppress the growth of lung cancer cells. Collectively, our study establishes a negative regulatory axis between two neddylation E2s with UBE2M ubiquitylating UBE2F, and two CRLs with CRL3 inactivating CRL5.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c1294b3f7126a2ca4240a4c30d180683Test
https://pubmed.ncbi.nlm.nih.gov/29932898Test

المؤلفون: Lili Zhao, Hua Li, Jie Xu, Lijun Jia, Dafydd G. Thomas, Dongping Wei, Mingjia Tan, Yongchao Zhao, Guoan Chen, David G. Beer, Yi Sun

المصدر: Journal of Clinical Investigation. 124:835-846

مصطلحات موضوعية: Male, Lung Neoplasms, Genotype, Cell Survival, Ubiquitin-Protein Ligases, chemical and pharmacologic phenomena, DEPTOR, medicine.disease_cause, Proto-Oncogene Proteins p21(ras), Mice, Cell Line, Tumor, Proto-Oncogene Proteins, parasitic diseases, medicine, Animals, Humans, Gene silencing, Gene Silencing, RNA, Small Interfering, Lung cancer, PI3K/AKT/mTOR pathway, Proportional Hazards Models, Gene knockdown, biology, Oncogene, NF-kappa B, General Medicine, Prognosis, medicine.disease, Ubiquitin ligase, Gene Expression Regulation, Neoplastic, body regions, Cell Transformation, Neoplastic, Mutation, ras Proteins, biology.protein, Cancer research, Female, Carcinogenesis, Oxidation-Reduction, Gene Deletion, Research Article

الوصف: Cullin-RING ligases (CRLs) are a family of E3 ubiquitin ligase complexes that rely on either RING-box 1 (RBX1) or sensitive to apoptosis gene (SAG), also known as RBX2, for activity. RBX1 and SAG are both overexpressed in human lung cancer; however, their contribution to patient survival and lung tumorigenesis is unknown. Here, we report that overexpression of SAG, but not RBX1, correlates with poor patient prognosis and more advanced disease. We found that SAG is overexpressed in murine KrasG12D-driven lung tumors and that Sag deletion suppressed lung tumorigenesis and extended murine life span. Using cultured lung cancer cells, we showed that SAG knockdown suppressed growth and survival, inactivated both NF-κB and mTOR pathways, and resulted in accumulation of tumor suppressor substrates, including p21, p27, NOXA, and BIM. Importantly, growth suppression by SAG knockdown was partially rescued by simultaneous knockdown of p21 or the mTOR inhibitor DEPTOR. Treatment with MLN4924, a small molecule inhibitor of CRL E3s, also inhibited the formation of KrasG12D-induced lung tumors through a similar mechanism involving inactivation of NF-κB and mTOR and accumulation of tumor suppressor substrates. Together, our results demonstrate that Sag is a Kras-cooperating oncogene that promotes lung tumorigenesis and suggest that targeting SAG-CRL E3 ligases may be an effective therapeutic approach for Kras-driven lung cancers.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d8f70e3cc2d59d5b6fb07e41f8fe2d98Test
https://doi.org/10.1172/jci70297Test

المؤلفون: Peng Kuang, Weihua Zhou, Mingjia Tan, Yi Sun, Qiang Zhang

المصدر: Scientific Reports

مصطلحات موضوعية: 0301 basic medicine, Ubiquitin-Protein Ligases, RBX1, chemical and pharmacologic phenomena, Plasma protein binding, Article, Mice, 03 medical and health sciences, 0302 clinical medicine, Ubiquitin, Cell Line, Tumor, parasitic diseases, Animals, Humans, Protein Isoforms, RNA, Small Interfering, Regulation of gene expression, Multidisciplinary, biology, Chemistry, Lysine, HEK 293 cells, Ubiquitination, Epithelial Cells, Mouse Embryonic Stem Cells, Cullin Proteins, beta-Transducin Repeat-Containing Proteins, Ubiquitin ligase, Cell biology, body regions, HEK293 Cells, 030104 developmental biology, Gene Expression Regulation, 030220 oncology & carcinogenesis, Proteolysis, Ubiquitin-Conjugating Enzymes, biology.protein, CUL1, Carrier Proteins, CUL5, Half-Life, Protein Binding, Signal Transduction

الوصف: SAG/RBX2 and RBX1 are two family members of RING components of Cullin-RING ligases (CRLs), required for their enzymatic activity. Previous studies showed that SAG prefers to bind with CUL5, as well as CUL1, whereas RBX1 binds exclusively to CULs1–4. Detailed biochemical difference between SAG and RBX1, and whether SAG mediates cross-talk between CRL5 and CRL1 are previously unknown. Here we report that the levels of SAG and β-TrCP1 are inversely correlated, and SAG-CUL5-βTrCP1 forms a complex under physiological condition. SAG-CUL5, but not RBX1-CUL1, negatively modulates β-TrCP1 levels by shortening its protein half-life through promoting its ubiquitylation via atypical K11-linkage. Consistently, chemical inducers of SAG reduced β-TrCP1 level. Furthermore, SAG mainly binds to E2s UBCH10 and UBE2S known to mediate K11 linkage of ubiquitin, whereas RBX1 exclusively binds to E2s CDC34 and UBCH5C, known to mediate K48 linkage of ubiquitin. Finally, silencing of either UBCH10 or UBE2S, but not UBCH5C, caused accumulation of endogenous β-TrCP1, suggesting that β-TrCP1 is a physiological substrate of SAG-UBCH10C/UBE2S. Our study, for the first time, differentiates SAG and RBX1 biochemically via their respective binding to different E2s; and shows a negative cross-talk between CRL5 and CRL1 through SAG mediated ubiquitylation of β-TrCP1.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b093e75b64fd5488deb522c73591bfe8Test
https://doi.org/10.1038/srep37441Test