1
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Luo L, Wu X, Fan J, Dong L, Wang M, Zeng Y, Li S, Yang W, Jiang J, Wang K. FBXO7 ubiquitinates PRMT1 to suppress serine synthesis and tumor growth in hepatocellular carcinoma. Nat Commun 2024; 15:4790. [PMID: 38839752 PMCID: PMC11153525 DOI: 10.1038/s41467-024-49087-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 05/23/2024] [Indexed: 06/07/2024] Open
Abstract
Cancer cells are often addicted to serine synthesis to support growth. How serine synthesis is regulated in cancer is not well understood. We recently demonstrated protein arginine methyltransferase 1 (PRMT1) is upregulated in hepatocellular carcinoma (HCC) to methylate and activate phosphoglycerate dehydrogenase (PHGDH), thereby promoting serine synthesis. However, the mechanisms underlying PRMT1 upregulation and regulation of PRMT1-PHGDH axis remain unclear. Here, we show the E3 ubiquitin ligase F-box-only protein 7 (FBXO7) inhibits serine synthesis in HCC by binding PRMT1, inducing lysine 37 ubiquitination, and promoting proteosomal degradation of PRMT1. FBXO7-mediated PRMT1 downregulation cripples PHGDH arginine methylation and activation, resulting in impaired serine synthesis, accumulation of reactive oxygen species (ROS), and inhibition of HCC cell growth. Notably, FBXO7 is significantly downregulated in human HCC tissues, and inversely associated with PRMT1 protein and PHGDH methylation level. Overall, our study provides mechanistic insights into the regulation of cancer serine synthesis by FBXO7-PRMT1-PHGDH axis, and will facilitate the development of serine-targeting strategies for cancer therapy.
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Affiliation(s)
- Li Luo
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China
- Center for Reproductive Medicine, Department of Gynecology and Obstetrics, West China Second University Hospital, Sichuan University, 610041, Chengdu, P. R. China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, 610041, Chengdu, P. R. China
| | - Xingyun Wu
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Jiawu Fan
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Lixia Dong
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Mao Wang
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Yan Zeng
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Sijia Li
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Wenyong Yang
- Department of Neurosurgery, Medical Research Center, The Third People's Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, 610014, Chengdu, P.R. China
| | - Jingwen Jiang
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China.
| | - Kui Wang
- West China School of Basic Medical Sciences & Forensic Medicine, State Key Laboratory of Biotherapy, West China Hospital, West China School of Public Health and West China Fourth Hospital, Sichuan University, 610041, Chengdu, P. R. China.
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2
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Al Rawi S, Simpson L, Agnarsdóttir G, McDonald NQ, Chernuha V, Elpeleg O, Zeviani M, Barker RA, Spiegel R, Laman H. Study of an FBXO7 patient mutation reveals Fbxo7 and PI31 co-regulate proteasomes and mitochondria. FEBS J 2024; 291:2565-2589. [PMID: 38466799 DOI: 10.1111/febs.17114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/18/2024] [Accepted: 02/29/2024] [Indexed: 03/13/2024]
Abstract
Mutations in FBXO7 have been discovered to be associated with an atypical parkinsonism. We report here a new homozygous missense mutation in a paediatric patient that causes an L250P substitution in the dimerisation domain of Fbxo7. This alteration selectively ablates the Fbxo7-PI31 interaction and causes a significant reduction in Fbxo7 and PI31 levels in patient cells. Consistent with their association with proteasomes, patient fibroblasts have reduced proteasome activity and proteasome subunits. We also show PI31 interacts with the MiD49/51 fission adaptor proteins, and unexpectedly, PI31 acts to facilitate SCFFbxo7-mediated ubiquitination of MiD49. The L250P mutation reduces the SCFFbxo7 ligase-mediated ubiquitination of a subset of its known substrates. Although MiD49/51 expression was reduced in patient cells, there was no effect on the mitochondrial network. However, patient cells show reduced levels of mitochondrial function and mitophagy, higher levels of ROS and are less viable under stress. Our study demonstrates that Fbxo7 and PI31 regulate proteasomes and mitochondria and reveals a new function for PI31 in enhancing the SCFFbxo7 E3 ubiquitin ligase activity.
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Affiliation(s)
- Sara Al Rawi
- Department of Pathology, University of Cambridge, UK
| | - Lorna Simpson
- Department of Pathology, University of Cambridge, UK
| | | | - Neil Q McDonald
- Signalling and Structural Biology Laboratory, The Francis Crick Institute, London, UK
- Department of Biological Sciences, Institute of Structural and Molecular Biology, London, UK
| | - Veronika Chernuha
- Pediatric Neurology Institute, Dana-Dwek Children's Hospital, Tel Aviv Medical Centre and Sackler Faculty of Medicine, Israel
| | - Orly Elpeleg
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Massimo Zeviani
- Mitochondrial Biology Unit, The MRC and University of Cambridge, UK
| | - Roger A Barker
- John van Geest Centre for Brain Repair, Cambridge, UK
- Wellcome-MRC Cambridge Stem Cell Institute, UK
| | - Ronen Spiegel
- Pediatric Department, Emek Medical Center, Afula, Israel
| | - Heike Laman
- Department of Pathology, University of Cambridge, UK
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3
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Webster NJG, Kumar D, Wu P. Dysregulation of RNA splicing in early non-alcoholic fatty liver disease through hepatocellular carcinoma. Sci Rep 2024; 14:2500. [PMID: 38291075 PMCID: PMC10828381 DOI: 10.1038/s41598-024-52237-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/16/2024] [Indexed: 02/01/2024] Open
Abstract
While changes in RNA splicing have been extensively studied in hepatocellular carcinoma (HCC), no studies have systematically investigated changes in RNA splicing during earlier liver disease. Mouse studies have shown that disruption of RNA splicing can trigger liver disease and we have shown that the splicing factor SRSF3 is decreased in the diseased human liver, so we profiled RNA splicing in liver samples from twenty-nine individuals with no-history of liver disease or varying degrees of non-alcoholic fatty liver disease (NAFLD). We compared our results with three publicly available transcriptome datasets that we re-analyzed for splicing events (SEs). We found many changes in SEs occurred during early liver disease, with fewer events occurring with the onset of inflammation and fibrosis. Many of these early SEs were enriched for SRSF3-dependent events and were associated with SRSF3 binding sites. Mapping the early and late changes to gene ontologies and pathways showed that the genes harboring these early SEs were involved in normal liver metabolism, whereas those harboring late SEs were involved in inflammation, fibrosis and proliferation. We compared the SEs with HCC data from the TCGA and observed that many of these early disease SEs are found in HCC samples and, furthermore, are correlated with disease survival. Changes in splicing factor expression are also observed, which may be associated with distinct subsets of the SEs. The maintenance of these SEs through the multi-year oncogenic process suggests that they may be causative. Understanding the role of these splice variants in metabolic liver disease progression may shed light on the triggers of liver disease progression and the pathogenesis of HCC.
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Affiliation(s)
- Nicholas J G Webster
- Jennifer Moreno VA Medical Center, San Diego, CA, 92161, USA.
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, CA, 92093, USA.
- Moores Cancer Center, University of California, San Diego, CA, 92093, USA.
| | - Deepak Kumar
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, CA, 92093, USA
| | - Panyisha Wu
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, CA, 92093, USA
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Li S, Chen Y, Xie Y, Zhan H, Zeng Y, Zeng K, Wang L, Zhan Z, Li C, Zhao L, Chen X, Tan Y, Wang Z, Bu J, Song Y, Deng F, Zhou A. FBXO7 Confers Mesenchymal Properties and Chemoresistance in Glioblastoma by Controlling Rbfox2-Mediated Alternative Splicing. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303561. [PMID: 37822160 PMCID: PMC10667838 DOI: 10.1002/advs.202303561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/06/2023] [Indexed: 10/13/2023]
Abstract
Mesenchymal glioblastoma (GBM) is highly resistant to radio-and chemotherapy and correlates with worse survival outcomes in GBM patients; however, the underlying mechanism determining the mesenchymal phenotype remains largely unclear. Herein, it is revealed that FBXO7, a substrate-recognition component of the SCF complex implicated in the pathogenesis of Parkinson's disease, confers mesenchymal properties and chemoresistance in GBM by controlling Rbfox2-mediated alternative splicing. Specifically, FBXO7 ubiquitinates Rbfox2 Lys249 through K63-linked ubiquitin chains upon arginine dimethylation at Arg341 and Arg441 by PRMT5, leading to Rbfox2 stabilization. FBXO7 controls Rbfox2-mediated splicing of mesenchymal genes, including FoxM1, Mta1, and Postn. FBXO7-induced exon Va inclusion of FoxM1 promotes FoxM1 phosphorylation by MEK1 and nuclear translocation, thereby upregulates CD44, CD9, and ID1 levels, resulting in GBM stem cell self-renewal and mesenchymal transformation. Moreover, FBXO7 is stabilized by temozolomide, and FBXO7 depletion sensitizes tumor xenografts in mice to chemotherapy. The findings demonstrate that the FBXO7-Rbfox2 axis-mediated splicing contributes to mesenchymal transformation and tumorigenesis, and targeting FBXO7 represents a potential strategy for GBM treatment.
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Affiliation(s)
- Shangbiao Li
- Department of Radiation OncologyZhujiang HospitalSouthern Medical UniversityGuangzhou510280China
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Yanwen Chen
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Yuxin Xie
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Hongchao Zhan
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Yu Zeng
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Kunlin Zeng
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Li Wang
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Ziling Zhan
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Cuiying Li
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Liqian Zhao
- Department of NeurosurgeryNanfang HospitalSouthern Medical UniversityGuangzhou510515China
| | - Xiaoxia Chen
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Yujing Tan
- Department of Radiation OncologyZhujiang HospitalSouthern Medical UniversityGuangzhou510280China
| | - Zhongyong Wang
- Department of NeurosurgeryThe Second Affiliated Hospital of Soochow UniversitySuzhou215004China
| | - Junguo Bu
- Department of Radiation OncologyZhujiang HospitalSouthern Medical UniversityGuangzhou510280China
| | - Ye Song
- Department of NeurosurgeryNanfang HospitalSouthern Medical UniversityGuangzhou510515China
| | - Fan Deng
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
| | - Aidong Zhou
- Department of Radiation OncologyZhujiang HospitalSouthern Medical UniversityGuangzhou510280China
- Department of Cell BiologySchool of Basic Medical ScienceSouthern Medical UniversityGuangzhou510515China
- Guangdong Province Key Laboratory of Molecular Tumor PathologySouthern Medical UniversityGuangzhou510515China
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5
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The characteristics of FBXO7 and its role in human diseases. Gene X 2023; 851:146972. [DOI: 10.1016/j.gene.2022.146972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/26/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022] Open
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6
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Lei T, Zhang Y, Wang X, Liu W, Feng W, Song W. A Diagnostic Model Using Exosomal Genes for Colorectal Cancer. Front Genet 2022; 13:863747. [PMID: 35910195 PMCID: PMC9334773 DOI: 10.3389/fgene.2022.863747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/19/2022] [Indexed: 12/24/2022] Open
Abstract
Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. Exosomes have great potential as liquid biopsy specimens due to their presence and stability in body fluids. However, the function and diagnostic values of exosomal genes in CRC are poorly understood. In the present study, exosomal data of CRC and healthy samples from the exoRBase 2.0 and Gene Expression Omnibus (GEO) databases were used, and 38 common exosomal genes were identified. Through the least absolute shrinkage and selection operator (Lasso) analysis, support vector machine recursive feature elimination (SVM-RFE) analysis, and logistic regression analysis, a diagnostic model of the training set was constructed based on 6 exosomal genes. The diagnostic model was internally validated in the test and exoRBase 2.0 database and externally validated in the GEO database. In addition, the co-expression analysis was used to cluster co-expression modules, and the enrichment analysis was performed on module genes. Then a protein–protein interaction and competing endogenous RNA network were constructed and 10 hub genes were identified using module genes. In conclusion, the results provided a comprehensive understanding of the functions of exosomal genes in CRC as well as a diagnostic model related to exosomal genes.
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Affiliation(s)
- Tianxiang Lei
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yongxin Zhang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaofeng Wang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Wenwei Liu
- Center for Digestive Disease, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Wei Feng
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Wu Song
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- *Correspondence: Wu Song,
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7
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Harris R, Yang M, Schmidt C, Royet C, Singh S, Natarajan A, Morris M, Frezza C, Laman H. Fbxo7 promotes Cdk6 activity to inhibit PFKP and glycolysis in T cells. J Cell Biol 2022; 221:e202203095. [PMID: 35670764 PMCID: PMC9178409 DOI: 10.1083/jcb.202203095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 12/24/2022] Open
Abstract
Fbxo7 is associated with cancer and Parkinson's disease. Although Fbxo7 recruits substrates for SCF-type ubiquitin ligases, it also promotes Cdk6 activation in a ligase-independent fashion. We discovered PFKP, the gatekeeper of glycolysis, in a screen for Fbxo7 substrates. PFKP is an essential Cdk6 substrate in some T-ALL cells. We investigated the molecular relationship between Fbxo7, Cdk6, and PFKP, and the effect of Fbxo7 on T cell metabolism, viability, and activation. Fbxo7 promotes Cdk6-independent ubiquitination and Cdk6-dependent phosphorylation of PFKP. Importantly, Fbxo7-deficient cells have reduced Cdk6 activity, and hematopoietic and lymphocytic cells show high expression and significant dependency on Fbxo7. CD4+ T cells with reduced Fbxo7 show increased glycolysis, despite lower cell viability and activation levels. Metabolomic studies of activated CD4+ T cells confirm increased glycolytic flux in Fbxo7-deficient cells, alongside altered nucleotide biosynthesis and arginine metabolism. We show Fbxo7 expression is glucose-responsive at the mRNA and protein level and propose Fbxo7 inhibits PFKP and glycolysis via its activation of Cdk6.
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Affiliation(s)
- Rebecca Harris
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Ming Yang
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Christina Schmidt
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Chloe Royet
- Pôle Chimie Balard Recherche, Institut des Biomolécules Max Mousseron-UMR5247, Montpellier, France
| | - Sarbjit Singh
- Eppley Institute for Cancer Research, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE
| | - Amarnath Natarajan
- Eppley Institute for Cancer Research, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE
| | - May Morris
- Pôle Chimie Balard Recherche, Institut des Biomolécules Max Mousseron-UMR5247, Montpellier, France
| | - Christian Frezza
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Heike Laman
- Department of Pathology, University of Cambridge, Cambridge, UK
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8
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McPhedran S, Lum JJ. Ubiquitinating the way to T cell metabolism. J Cell Biol 2022; 221:e202206006. [PMID: 35695892 PMCID: PMC9198946 DOI: 10.1083/jcb.202206006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In this issue, Harris et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202203095) show that phosphofructokinase is a substrate for ubiquitination by Fbxo7, a key protein in the ubiquitination pathway. Their findings point to a new interplay between metabolic enzyme degradation in the regulation of T cells.
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Affiliation(s)
- Sarah McPhedran
- Trev and Joyce Deeley Research Centre, BC Cancer, Victoria, BC, Canada
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Julian J. Lum
- Trev and Joyce Deeley Research Centre, BC Cancer, Victoria, BC, Canada
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
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9
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Wu M, Qiu Q, Zhou Q, Li J, Yang J, Zheng C, Luo A, Li X, Zhang H, Cheng X, Lu W, Liu P, Lu B, Lu Y. circFBXO7/miR-96-5p/MTSS1 axis is an important regulator in the Wnt signaling pathway in ovarian cancer. Mol Cancer 2022; 21:137. [PMID: 35768865 PMCID: PMC9241180 DOI: 10.1186/s12943-022-01611-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 06/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND CircRNAs are a novel class of evolutionarily conserved noncoding RNA molecules that form covalently closed continuous loop structures without 5' caps and 3' poly(A) tails. Accumulating evidence suggests that circRNAs play important regulatory roles in cancer and are promising biomarkers for cancer diagnosis and prognosis, as well as targets for cancer therapy. In this study, we identify and explore the role of a novel circRNA, circFBXO7, in ovarian cancer. METHODS rRNA-depleted RNA-sequencing was performed to identify differentially expressed circRNAs between ovarian cancerous and normal tissues. qRT-PCR and single-molecule RNA in-situ hybridization was used to quantify circFBXO7 expression in tumor tissues. The association of circFBXO7 expression with patient prognosis was evaluated by Kaplan-Meier survival analysis. The biological function of circFBXO7 was also investigated using loss-of-function and gain-of-function assays in vivo and in vitro. Luciferase reporter and TOP/FOP-Flash reporter assays were then conducted together with RNA immunoprecipitation and western blot to assess the circFBXO7/miR-96-5p/MTSS1/Wnt/β-catenin axis. RESULTS circFBXO7 was downregulated in ovarian cancer which was associated with poor prognosis. Biologically, circFBXO7 overexpression significantly suppressed ovarian cancer cell proliferation, migration, and invasion in vitro, and inhibited tumor growth and metastasis in vivo, whereas its knockdown exerted an opposite role. Mechanistically, circFBXO7 functioned as a competing endogenous RNA for miR-96-5p to regulate the expression of MTSS1. Consequently, downregulation of MTSS1 led to excessive accumulation of β-catenin and increased phosphorylation of GSK3β, leading to the translocation of β-catenin to the nucleus, thereby activating the Wnt/β-catenin signaling pathway and ultimately promoting ovarian cancer progression. CONCLUSIONS Our findings indicate that circFBXO7 acts as a bone fide tumor suppressor in ovarian cancer and that the circFBXO7/miR-96-5p/MTSS1 axis is an important regulator in the Wnt/β-catenin signaling pathway which may provide a promising target for ovarian cancer therapy.
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Affiliation(s)
- Mengting Wu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Qiongzi Qiu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Qing Zhou
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Jia Li
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Juze Yang
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Chengcai Zheng
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Aoran Luo
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Xufan Li
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Honghe Zhang
- Department of Pathology, Research Unit of Intelligence Classification of Tumor Pathology and Precision Therapy, Chinese Academy of Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China.,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China
| | - Xiaodong Cheng
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China.,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China
| | - Weiguo Lu
- Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.,Women's Reproductive Health Key Laboratory of Zhejiang Province, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China
| | - Pengyuan Liu
- Key Laboratory of Precision Medicine in Diagnosis and Monitoring Research of Zhejiang Province, Sir Run Run Shaw Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China. .,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.
| | - Bingjian Lu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China. .,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.
| | - Yan Lu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310006, Zhejiang, China. .,Cancer Center, Zhejiang University, Hangzhou, 310013, Zhejiang, China.
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10
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Lee SH, Jung S, Lee YJ, Hyun M, Chung KC. FBXO7 triggers caspase 8-mediated proteolysis of the transcription factor FOXO4 and exacerbates neuronal cytotoxicity. J Biol Chem 2021; 297:101426. [PMID: 34800438 PMCID: PMC8665361 DOI: 10.1016/j.jbc.2021.101426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/05/2021] [Accepted: 11/15/2021] [Indexed: 01/26/2023] Open
Abstract
Parkinson's disease (PD) is characterized by the progressive loss of midbrain dopamine neurons in the substantia nigra. Mutations in the F-box only protein 7 gene (Fbxo7) have been reported to cause an autosomal recessive form of early-onset familial PD. FBXO7 is a part of the SKP1-Cullin1-F-box (SCF) E3 ubiquitin ligase complex, which mediates ubiquitination of numerous substrates. FBXO7 also regulates mitophagy, cell growth, and proteasome activity. A member of the FOXO family, the transcription factor FOXO4, is also known to modulate several cellular responses, including cell cycle progression and apoptosis; however, the relationship between FBXO7 and FOXO4 has not been investigated. In this study, we determined that FBXO7 binds to FOXO4 and negatively regulates intracellular FOXO4 levels. Interestingly, we also found that FBXO7-mediated degradation of FOXO4 did not occur through either of two major proteolysis systems, the ubiquitin-proteasome system or the lysosome-autophagy pathway, although it was blocked by a caspase 8-specific inhibitor and caspase 8-knockdown. Moreover, intracellular FOXO4 levels were greatly reduced in dopaminergic MN9D cells following treatment with neurotoxic 6-hydroxydopamine (6-OHDA), which was produced upon FBXO7-mediated and caspase 8-mediated proteolysis. Taken together, these results suggest that FOXO4 is negatively regulated in FBXO7-linked PD through caspase 8 activation, suppressing the cytoprotective effect of FOXO4 during 6-OHDA-induced neuronal cell death.
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Affiliation(s)
- Su Hyoun Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Sungyeon Jung
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Yun Ju Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Minju Hyun
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Kwang Chul Chung
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
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11
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Palmer MCL, Neudorf NM, Farrell AC, Razi T, Lichtensztejn Z, McManus KJ. The F-box protein, FBXO7 is required to maintain chromosome stability in humans. Hum Mol Genet 2021; 31:1471-1486. [PMID: 34791250 PMCID: PMC9071473 DOI: 10.1093/hmg/ddab330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 11/19/2022] Open
Abstract
Despite the high morbidity and mortality rates associated with colorectal cancer (CRC), the aberrant genes and mechanisms driving CRC pathogenesis remain poorly understood. Chromosome instability (CIN), or ongoing changes in chromosome numbers, is a predominant form of genome instability associated with ~85% of CRCs, suggesting it may be a key mechanism driving CRC oncogenesis. CIN enables the acquisition of copy number alterations conferring selective growth, proliferation and survival advantages that promote cellular transformation. Despite these associations, the aberrant genes underlying CIN remain largely unknown. Candidate CIN gene FBXO7 encodes an F-box protein, a subunit of the SKP1-CUL1-FBOX (SCF) complex that confers substrate specificity to the complex and targets proteins for subsequent degradation by the 26S proteasome. Recently, the genes encoding the three core SCF complex members were identified as CIN genes; however, it is unknown whether F-box proteins exhibit similar integral roles in maintaining chromosome stability. Using short- small interfering RNA (siRNA) and long- (CRISPR/Cas9) term approaches, we show that reduced FBXO7 expression induces CIN in various colonic epithelial cell contexts, whereas FBXO7 knockout clones also exhibit hallmarks associated with cellular transformation, namely increased clonogenic and anchorage-independent growth. Collectively, these data demonstrate that FBXO7 is required to maintain genome stability identifying FBXO7 a novel CIN gene whose reduced expression may contribute to CRC development and progression.
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Affiliation(s)
- Michaela C L Palmer
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Biochemistry & Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Nicole M Neudorf
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Biochemistry & Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Ally C Farrell
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Biochemistry & Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Tooba Razi
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Biochemistry & Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Zelda Lichtensztejn
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Biochemistry & Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Kirk J McManus
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Biochemistry & Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
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12
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Harris R, Randle S, Laman H. Analysis of the FBXO7 promoter reveals overlapping Pax5 and c-Myb binding sites functioning in B cells. Biochem Biophys Res Commun 2021; 554:41-48. [PMID: 33774278 PMCID: PMC8082276 DOI: 10.1016/j.bbrc.2021.03.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 03/10/2021] [Indexed: 02/03/2023]
Abstract
Fbxo7 is a key player in the differentiation and function of numerous blood cell types, and in neurons, oligodendrocytes and spermatocytes. In an effort to gain insight into the physiological and pathological settings where Fbxo7 is likely to play a key role, we sought to define the transcription factors which direct FBXO7 expression. Using sequence alignments across 28 species, we defined the human FBXO7 promoter and found that it contains two conserved regions enriched for multiple transcription factor binding sites. Many of these have roles in either neuronal or haematopoietic development. Using various FBXO7 promoter reporters, we found ELF4, Pax5 and c-Myb have functional binding sites that activate transcription. We find endogenous Pax5 is bound to the FBXO7 promoter in pre-B cells, and that the exogenous expression of Pax5 represses Fbxo7 transcription in early pro-B cells.
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Affiliation(s)
- Rebecca Harris
- University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom
| | - Suzanne Randle
- University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom
| | - Heike Laman
- University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom.
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13
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Huang T, Fang L, He R, Weng H, Chen X, Ye Q, Qu D. Fbxo7 and Pink1 play a reciprocal role in regulating their protein levels. Aging (Albany NY) 2020; 13:77-88. [PMID: 33291077 PMCID: PMC7835017 DOI: 10.18632/aging.202236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022]
Abstract
Pink1, Parkin and Fbxo7, three autosomal recessive familial genes of Parkinson’s disease (PD), have been implicated in mitophagy pathways for quality control and clearance of damaged mitochondria, but the interplay of these three genes still remains unclear. Here we present that Fbxo7 and Pink1 play a reciprocal role in the regulation of their protein levels. Regardless of the genotypes of Fbxo7, the wild type and the PD familial mutants of Fbxo7 stabilize the processed form of Pink1, supporting the prior study that none of the PD familial mutations in Fbxo7 have an effect on the interaction with Pink1. On the other hand, the interaction of Fbxo7 with Bag2 further facilitates its capability to stabilize Pink1. Intriguingly, the stabilization of Fbxo7 by Pink1 is specifically observed in substantial nigra pars compacta but striatum and cerebral cortex. Taken together, our findings support the notion that Fbxo7 as a scaffold protein has a chaperon activity in the stabilization of proteins.
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Affiliation(s)
- Tianwen Huang
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Lijun Fang
- Department of Ophthalmology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Raoli He
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Huidan Weng
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Xiaochun Chen
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Qinyong Ye
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Dianbo Qu
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China.,Hotchkiss Brain Institute, Department of Clinical Neurosciences, University of Calgary, Calgary T2N 4N1, Alberta, Canada
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14
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Sturchio A, Dwivedi AK, Vizcarra JA, Chirra M, Keeling EG, Mata IF, Kauffman MA, Pandey MK, Roviello G, Comi C, Versino M, Marsili L, Espay AJ. Genetic parkinsonisms and cancer: a systematic review and meta-analysis. Rev Neurosci 2020; 32:159-167. [PMID: 33151182 DOI: 10.1515/revneuro-2020-0083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/20/2020] [Indexed: 12/11/2022]
Abstract
Genes associated with parkinsonism may also be implicated in carcinogenesis, but their interplay remains unclear. We systematically reviewed studies (PubMed 1967-2019) reporting gene variants associated with both parkinsonism and cancer. Somatic variants were examined in cancer samples, whereas germline variants were examined in cancer patients with both symptomatic and asymptomatic (carriers) genetic parkinsonisms. Pooled proportions were calculated with random-effects meta-analyses. Out of 9,967 eligible articles, 60 were included. Of the 28 genetic variants associated with parkinsonism, six were also associated with cancer. In cancer samples, SNCA was predominantly associated with gastrointestinal cancers, UCHL1 with breast cancer, and PRKN with head-and-neck cancers. In asymptomatic carriers, LRRK2 was predominantly associated with gastrointestinal and prostate cancers, PRKN with prostate and genitourinary tract cancers, GBA with sarcoma, and 22q11.2 deletion with leukemia. In symptomatic genetic parkinsonism, LRRK2 was associated with nonmelanoma skin cancers and breast cancers, and PRKN with head-and-neck cancers. Cancer was more often manifested in genetic parkinsonisms compared to asymptomatic carriers. These results suggest that intraindividual genetic contributions may modify the co-occurrence of cancer and neurodegeneration.
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Affiliation(s)
- Andrea Sturchio
- Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, 260 Stetson St., Cincinnati, OH45219, USA
| | - Alok K Dwivedi
- Division of Biostatistics & Epidemiology, Department of Molecular and Translational Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA
| | - Joaquin A Vizcarra
- Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, 260 Stetson St., Cincinnati, OH45219, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Martina Chirra
- Department of Oncology, Medical Oncology Unit, University of Siena, Siena, Italy
| | - Elizabeth G Keeling
- Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, 260 Stetson St., Cincinnati, OH45219, USA
| | - Ignacio F Mata
- Lerner Research Institute, Genomic Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Marcelo A Kauffman
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología José María Ramos Mejía, Buenos Aires, Argentina
| | - Manoj K Pandey
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center and Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | | | - Cristoforo Comi
- Neurology Unit, Department of Translational Medicine, Interdisciplinary Research Centre of Autoimmune Diseases, Movement Disorders Centre, University of Piemonte Orientale, Novara, Italy
| | | | - Luca Marsili
- Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, 260 Stetson St., Cincinnati, OH45219, USA
| | - Alberto J Espay
- Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, 260 Stetson St., Cincinnati, OH45219, USA
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15
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Hynes-Smith RW, Wittorf KJ, Buckley SM. Regulation of Normal and Malignant Hematopoiesis by FBOX Ubiquitin E3 Ligases. Trends Immunol 2020; 41:1128-1140. [PMID: 33160841 DOI: 10.1016/j.it.2020.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/13/2022]
Abstract
Hematopoiesis is responsible for numerous functions, ranging from oxygen transportation to host defense, to injury repair. This process of hematopoiesis is maintained throughout life by hematopoietic stem cells and requires a controlled balance between self-renewal, differentiation, and quiescence. Disrupting this balance can result in hematopoietic malignancies, including anemia, immune deficiency, leukemia, and lymphoma. Recent work has shown that FBOX E3 ligases, a substrate recognition component of the ubiquitin proteasome system (UPS), have an integral role in maintaining this balance. In this review, we detail how FBOX proteins target specific proteins for degradation to regulate hematopoiesis through cell processes, such as cell cycle, development, and apoptosis.
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Affiliation(s)
- R Willow Hynes-Smith
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Karli J Wittorf
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shannon M Buckley
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.
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16
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The E3 ubiquitin ligase SCF(Fbxo7) mediates proteasomal degradation of UXT isoform 2 (UXT-V2) to inhibit the NF-κB signaling pathway. Biochim Biophys Acta Gen Subj 2020; 1865:129754. [PMID: 33010352 PMCID: PMC8063000 DOI: 10.1016/j.bbagen.2020.129754] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 12/18/2022]
Abstract
Background Ubiquitously eXpressed Transcript isoform 2 (UXT—V2) is a prefoldin-like protein involved in NF-κB signaling, apoptosis, and the androgen and estrogen response. UXT-V2 is a cofactor in the NF-κB transcriptional enhanceosome, and its knockdown inhibits TNF-α -induced NF-κB activation. Fbxo7 is an F-box protein that interacts with SKP1, Cullin1 and RBX1 proteins to form an SCF(Fbxo7) E3 ubiquitin ligase complex. Fbxo7 negatively regulates NF-κB signaling through TRAF2 and cIAP1 ubiquitination. Methods We combine co-immunoprecipitation, ubiquitination in vitro and in vivo, cycloheximide chase assay, ubiquitin chain restriction analysis and microscopy to investigate interaction between Fbxo7 and overexpressed UXT-V2-HA. Results The Ubl domain of Fbxo7 contributes to interaction with UXT—V2. This substrate is polyubiquitinated by SCF(Fbxo7) with K48 and K63 ubiquitin chain linkages in vitro and in vivo. This post-translational modification decreases UXT-V2 stability and promotes its proteasomal degradation. We further show that UXT—V1, an alternatively spliced isoform of UXT, containing 12 additional amino acids at the N-terminus as compared to UXT—V2, also interacts with and is ubiquitinated by Fbxo7. Moreover, FBXO7 knockdown promotes UXT-V2 accumulation, and the overexpression of Fbxo7-ΔF-box protects UXT-V2 from proteasomal degradation and enhances the responsiveness of NF-κB reporter. We find that UXT-V2 colocalizes with Fbxo7 in the cell nucleus. Conclusions Together, our study reveals that SCF(Fbxo7) mediates the proteasomal degradation of UXT-V2 causing the inhibition of the NF-κB signaling pathway. General significance Discovering new substrates of E3 ubiquitin-ligase SCF(Fbxo7) contributes to understand its function in different diseases such as cancer and Parkinson. UXT-V2 is a canonical substrate of SCF(Fbxo7) E3 ubiquitin ligase. Fbxo7 interacts with both UXT-V1 and UXT—V2. UXT-V2 recruits Fbxo7 to the cell nuclei. Fbxo7 inhibit NF-kB pathway through degradation of UXT-V2.
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17
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Trinh D, Israwi AR, Arathoon LR, Gleave JA, Nash JE. The multi-faceted role of mitochondria in the pathology of Parkinson's disease. J Neurochem 2020; 156:715-752. [PMID: 33616931 DOI: 10.1111/jnc.15154] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022]
Abstract
Mitochondria are essential for neuronal function. They produce ATP to meet energy demands, regulate homeostasis of ion levels such as calcium and regulate reactive oxygen species that cause oxidative cellular stress. Mitochondria have also been shown to regulate protein synthesis within themselves, as well as within the nucleus, and also influence synaptic plasticity. These roles are especially important for neurons, which have higher energy demands and greater susceptibility to stress. Dysfunction of mitochondria has been associated with several neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, Huntington's disease, Glaucoma and Amyotrophic Lateral Sclerosis. The focus of this review is on how and why mitochondrial function is linked to the pathology of Parkinson's disease (PD). Many of the PD-linked genetic mutations which have been identified result in dysfunctional mitochondria, through a wide-spread number of mechanisms. In this review, we describe how susceptible neurons are predisposed to be vulnerable to the toxic events that occur during the neurodegenerative process of PD, and how mitochondria are central to these pathways. We also discuss ways in which proteins linked with familial PD control mitochondrial function, both physiologically and pathologically, along with their implications in genome-wide association studies and risk assessment. Finally, we review potential strategies for disease modification through mitochondrial enhancement. Ultimately, agents capable of both improving and/or restoring mitochondrial function, either alone, or in conjunction with other disease-modifying agents may halt or slow the progression of neurodegeneration in Parkinson's disease.
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Affiliation(s)
- Dennison Trinh
- Department of Biological Sciences, University of Toronto Scarborough, Centre for Neurobiology of Stress, Toronto, ON, Canada
| | - Ahmad R Israwi
- Department of Biological Sciences, University of Toronto Scarborough, Centre for Neurobiology of Stress, Toronto, ON, Canada
| | - Lindsay R Arathoon
- Department of Biological Sciences, University of Toronto Scarborough, Centre for Neurobiology of Stress, Toronto, ON, Canada
| | - Jacqueline A Gleave
- Department of Biological Sciences, University of Toronto Scarborough, Centre for Neurobiology of Stress, Toronto, ON, Canada
| | - Joanne E Nash
- Department of Biological Sciences, University of Toronto Scarborough, Centre for Neurobiology of Stress, Toronto, ON, Canada
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18
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Udasin RG, Gottfried Y, Fabre B, Bercovich B, Ziv T, Ciechanover A. The p105 NF-ĸB precursor is a pseudo substrate of the ubiquitin ligase FBXO7, and its binding to the ligase stabilizes it and results in stimulated cell proliferation. Biochem Biophys Res Commun 2020; 558:224-230. [PMID: 32933748 DOI: 10.1016/j.bbrc.2020.08.098] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 08/25/2020] [Indexed: 01/11/2023]
Abstract
The NF-κB transcription factor is involved in inflammation and cell proliferation, survival, and transformation. It is a heterodimer made of p50 or p52 and a member of the Rel family of proteins. p50 and p52 are derived from limited ubiquitin- and proteasome-mediated proteolytic processing of the larger precursors p105 and p100, respectively. Both precursors can be either processed or completely degraded by the ubiquitin-proteasome system. Previous work in our laboratory identified KPC1 as a ubiquitin ligase that mediates processing of p105 to the p50 subunit. Overexpression of the ligase leads to increased level of p50 with a resultant marked tumor-suppressive effect. In the present study, we identify FBXO7, a known ubiquitin ligase that binds to p105 and ubiquitinates it, but surprisingly, leads to its accumulation and to that of p65 - the Rel partner of p50 - and to increased cell proliferation. Importantly, a ΔF-Box mutant of FBXO7 which is inactive has similar effects on accumulation of p105 and cell proliferation, strongly suggesting that p105 is a pseudo substrate of FBXO7.
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Affiliation(s)
- Ronald G Udasin
- The Technion Rappaport Integrated Cancer Center (T-RICC), The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, 3109601, Israel
| | - Yossi Gottfried
- The Technion Rappaport Integrated Cancer Center (T-RICC), The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, 3109601, Israel
| | - Bertrand Fabre
- The Technion Rappaport Integrated Cancer Center (T-RICC), The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, 3109601, Israel
| | - Beatrice Bercovich
- The Technion Rappaport Integrated Cancer Center (T-RICC), The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, 3109601, Israel
| | - Tamar Ziv
- The Smoler Proteomics Center, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Aaron Ciechanover
- The Technion Rappaport Integrated Cancer Center (T-RICC), The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, 3109601, Israel.
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19
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Tekcham DS, Chen D, Liu Y, Ling T, Zhang Y, Chen H, Wang W, Otkur W, Qi H, Xia T, Liu X, Piao HL, Liu H. F-box proteins and cancer: an update from functional and regulatory mechanism to therapeutic clinical prospects. Am J Cancer Res 2020; 10:4150-4167. [PMID: 32226545 PMCID: PMC7086354 DOI: 10.7150/thno.42735] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/04/2020] [Indexed: 12/16/2022] Open
Abstract
E3 ubiquitin ligases play a critical role in cellular mechanisms and cancer progression. F-box protein is the core component of the SKP1-cullin 1-F-box (SCF)-type E3 ubiquitin ligase and directly binds to substrates by various specific domains. According to the specific domains, F-box proteins are further classified into three sub-families: 1) F-box with leucine rich amino acid repeats (FBXL); 2) F-box with WD 40 amino acid repeats (FBXW); 3) F-box only with uncharacterized domains (FBXO). Here, we summarize the substrates of F-box proteins, discuss the important molecular mechanism and emerging role of F-box proteins especially from the perspective of cancer development and progression. These findings will shed new light on malignant tumor progression mechanisms, and suggest the potential role of F-box proteins as cancer biomarkers and therapeutic targets for future cancer treatment.
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20
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Yan L, Lin M, Pan S, Assaraf YG, Wang ZW, Zhu X. Emerging roles of F-box proteins in cancer drug resistance. Drug Resist Updat 2019; 49:100673. [PMID: 31877405 DOI: 10.1016/j.drup.2019.100673] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 12/24/2022]
Abstract
Chemotherapy continues to be a major treatment strategy for various human malignancies. However, the frequent emergence of chemoresistance compromises chemotherapy efficacy leading to poor prognosis. Thus, overcoming drug resistance is pivotal to achieve enhanced therapy efficacy in various cancers. Although increased evidence has revealed that reduced drug uptake, increased drug efflux, drug target protein alterations, drug sequestration in organelles, enhanced drug metabolism, impaired DNA repair systems, and anti-apoptotic mechanisms, are critically involved in drug resistance, the detailed resistance mechanisms have not been fully elucidated in distinct cancers. Recently, F-box protein (FBPs), key subunits in Skp1-Cullin1-F-box protein (SCF) E3 ligase complexes, have been found to play critical roles in carcinogenesis, tumor progression, and drug resistance through degradation of their downstream substrates. Therefore, in this review, we describe the functions of FBPs that are involved in drug resistance and discuss how FBPs contribute to the development of cancer drug resistance. Furthermore, we propose that targeting FBPs might be a promising strategy to overcome drug resistance and achieve better treatment outcome in cancer patients. Lastly, we state the limitations and challenges of using FBPs to overcome chemotherapeutic drug resistance in various cancers.
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Affiliation(s)
- Linzhi Yan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Min Lin
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Shuya Pan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Yehuda G Assaraf
- The Fred Wyszkowski Cancer Research Lab, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 3200003, Israel.
| | - Zhi-Wei Wang
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Xueqiong Zhu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China.
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21
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Myelinating Glia-Specific Deletion of Fbxo7 in Mice Triggers Axonal Degeneration in the Central Nervous System Together with Peripheral Neuropathy. J Neurosci 2019; 39:5606-5626. [PMID: 31085610 DOI: 10.1523/jneurosci.3094-18.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/10/2019] [Accepted: 04/24/2019] [Indexed: 12/25/2022] Open
Abstract
Myelination of axons facilitates the rapid propagation of electrical signals and the long-term integrity of axons. The ubiquitin-proteasome system is essential for proper protein homeostasis, which is particularly crucial for interactions of postmitotic cells. In our study, we examined how the E3 ubiquitin ligase FBXO7-SCF (SKP1, Cul1, F-box protein) expressed in myelinating cells affects the axon-myelin unit. Deletion of Fbxo7 in oligodendrocytes and Schwann cells in mice using the Cnp1-Cre driver line led to motor impairment due to hindlimb paresis. It did not result in apoptosis of myelinating cells, nor did it affect the proper myelination of axons or lead to demyelination. It however triggered axonal degeneration in the CNS and resulted in the severe degeneration of axons in the PNS, inducing a full-blown neuropathy. Both the CNS and PNS displayed inflammation, while the PNS was also characterized by fibrosis, massive infiltration of macrophages, and edema. Tamoxifen-induced deletion of Fbxo7, after myelination using the Plp1-CreERT2 line, led to a small number of degenerated axons and hence a very mild peripheral neuropathy. Interestingly, loss of Fbxo7 also resulted in reduced proteasome activity in Schwann cells but not in cerebellar granule neurons, indicating a specific sensitivity of the former cell type. Together, our results demonstrate an essential role for FBXO7 in myelinating cells to support associated axons, which is fundamental to the proper developmental establishment and the long-term integrity of the axon-myelin unit.SIGNIFICANCE STATEMENT The myelination of axons facilitates the fast propagation of electrical signals and the trophic support of the myelin-axon unit. Here, we report that deletion of Fbxo7 in myelinating cells in mice triggered motor impairment but had no effect on myelin biogenesis. Loss of Fbxo7 in myelinating glia, however, led to axonal degeneration in the CNS and peripheral neuropathy of the axonal type. In addition, we found that Schwann cells were particularly sensitive to Fbxo7 deficiency reflected by reduced proteasome activity. Based on these findings, we conclude that Fbxo7 is essential for the support of the axon-myelin unit and long-term axonal health.
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22
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FBXO7 sensitivity of phenotypic traits elucidated by a hypomorphic allele. PLoS One 2019; 14:e0212481. [PMID: 30840666 PMCID: PMC6402633 DOI: 10.1371/journal.pone.0212481] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 02/04/2019] [Indexed: 11/19/2022] Open
Abstract
FBXO7 encodes an F box containing protein that interacts with multiple partners to facilitate numerous cellular processes and has a canonical role as part of an SCF E3 ubiquitin ligase complex. Mutation of FBXO7 is responsible for an early onset Parkinsonian pyramidal syndrome and genome-wide association studies have linked variants in FBXO7 to erythroid traits. A putative orthologue in Drosophila, nutcracker, has been shown to regulate the proteasome, and deficiency of nutcracker results in male infertility. Therefore, we reasoned that modulating Fbxo7 levels in a murine model could provide insights into the role of this protein in mammals. We used a targeted gene trap model which retained 4-16% residual gene expression and assessed the sensitivity of phenotypic traits to gene dosage. Fbxo7 hypomorphs showed regenerative anaemia associated with a shorter erythrocyte half-life, and male mice were infertile. Alterations to T cell phenotypes were also observed, which intriguingly were both T cell intrinsic and extrinsic. Hypomorphic mice were also sensitive to infection with Salmonella, succumbing to a normally sublethal challenge. Despite these phenotypes, Fbxo7 hypomorphs were produced at a normal Mendelian ratio with a normal lifespan and no evidence of neurological symptoms. These data suggest that erythrocyte survival, T cell development and spermatogenesis are particularly sensitive to Fbxo7 gene dosage.
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Georges A, Coyaud E, Marcon E, Greenblatt J, Raught B, Frappier L. USP7 Regulates Cytokinesis through FBXO38 and KIF20B. Sci Rep 2019; 9:2724. [PMID: 30804394 PMCID: PMC6389929 DOI: 10.1038/s41598-019-39368-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/18/2019] [Indexed: 01/13/2023] Open
Abstract
The ubiquitin specific protease 7 (USP7 or HAUSP) is known to regulate a variety of cellular processes by binding and deubiquitylating specific target proteins. To gain a more comprehensive understanding of its interactions and functions, we used affinity purification coupled to mass spectrometry to profile USP7 interactions. This revealed a novel interaction with FBXO38, a poorly characterized F-box protein. We showed that USP7 stabilizes FBXO38 dependent on its catalytic activity by protecting FBXO38 from proteasomal degradation. We used a BioID approach to profile the protein interactions (and putative functions) of FBXO38, revealing an interaction with KIF20B, a Kinesin-6 protein required for efficient cytokinesis. FBXO38 was shown to function independently from an SCF complex to stabilize KIF20B. Consequently, depletion of either FBXO38 or USP7 led to dramatic decreases in KIF20B levels and KIF20B at the midbody, which were manifested in cytokinetic defects. Furthermore, cytokinetic defects associated with USP7 silencing were rescued by restoring FBXO38 or KIF20B. The results indicate a novel mechanism of regulating cytokinesis through USP7 and FBXO38.
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Affiliation(s)
- Anna Georges
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Etienne Coyaud
- The Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, M5G 1L7, Canada
| | - Edyta Marcon
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Jack Greenblatt
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Donnelly Centre, University of Toronto, Toronto, Canada
| | - Brian Raught
- The Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Lori Frappier
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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Zhou ZD, Lee JCT, Tan EK. Pathophysiological mechanisms linking F-box only protein 7 (FBXO7) and Parkinson's disease (PD). MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 778:72-78. [PMID: 30454685 DOI: 10.1016/j.mrrev.2018.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/11/2018] [Accepted: 10/12/2018] [Indexed: 12/12/2022]
Abstract
Mutations of F-box only protein 7 (FBXO7) gene are associated with a severe form of autosomal recessive juvenile Parkinson's disease (PD) (PARK15) with clinical features of Parkinsonian-Pyramidal syndrome (PPS). FBXO7 is an adaptor protein in SCFFBXO7 ubiquitin E3 ligase complex that recognizes and mediates degradative or non-degradative ubiquitination of substrates. The FBXO7 protein can regulate cell cycle, proliferation, mitochondrial and proteasome functions via interactions with multiple target proteins. Five PARK15-linked FBXO7 gene mutations and several PD-associated single nucleotide polymorphisms (SNP) have been identified so far. WT FBXO7 proteins possess dual protective and deleterious functions, whereas PARK15-linked FBXO7 mutants are toxic. FBXO7 is a stress response protein and stress challenges can promote translocation of FBXO7 protein from nucleus into mitochondria and even form deleterious protein aggregate in mitochondria. FBXO7 mutants aggravate protein aggregation in mitochondria and inhibit mitophagy. The pathological mechanisms concerning FBXO7-relevant protein aggregation, mitochondria impairment, reactive oxygen species (ROS) generation and mitophagy modulation in PARK15 pathogenesis are highlighted and discussed in the current review.
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Affiliation(s)
- Zhi Dong Zhou
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, 308433, Singapore; Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, 8 College Road, 169857, Singapore.
| | - Ji Chao Tristan Lee
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, 308433, Singapore.
| | - Eng King Tan
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, 308433, Singapore; Department of Neurology, Singapore General Hospital, Outram Road, 169608, Singapore; Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, 8 College Road, 169857, Singapore.
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25
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Ubiquitin and Parkinson's disease through the looking glass of genetics. Biochem J 2017; 474:1439-1451. [PMID: 28408429 PMCID: PMC5390927 DOI: 10.1042/bcj20160498] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 02/20/2017] [Accepted: 02/20/2017] [Indexed: 12/12/2022]
Abstract
Biochemical alterations found in the brains of Parkinson's disease (PD) patients indicate that cellular stress is a major driver of dopaminergic neuronal loss. Oxidative stress, mitochondrial dysfunction, and ER stress lead to impairment of the homeostatic regulation of protein quality control pathways with a consequent increase in protein misfolding and aggregation and failure of the protein degradation machinery. Ubiquitin signalling plays a central role in protein quality control; however, prior to genetic advances, the detailed mechanisms of how impairment in the ubiquitin system was linked to PD remained mysterious. The discovery of mutations in the α-synuclein gene, which encodes the main protein misfolded in PD aggregates, together with mutations in genes encoding ubiquitin regulatory molecules, including PTEN-induced kinase 1 (PINK1), Parkin, and FBX07, has provided an opportunity to dissect out the molecular basis of ubiquitin signalling disruption in PD, and this knowledge will be critical for developing novel therapeutic strategies in PD that target the ubiquitin system.
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26
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Patel SP, Randle SJ, Gibbs S, Cooke A, Laman H. Opposing effects on the cell cycle of T lymphocytes by Fbxo7 via Cdk6 and p27. Cell Mol Life Sci 2016; 74:1553-1566. [PMID: 27915416 PMCID: PMC5357273 DOI: 10.1007/s00018-016-2427-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/28/2016] [Accepted: 11/21/2016] [Indexed: 11/30/2022]
Abstract
G1 phase cell cycle proteins, such as cyclin-dependent kinase 6 (Cdk6) and its activating partners, the D-type cyclins, are important regulators of T-cell development and function. An F-box protein, called F-box only protein 7 (Fbxo7), acts as a cell cycle regulator by enhancing cyclin D-Cdk6 complex formation and stabilising levels of p27, a cyclin-dependent kinase inhibitor. We generated a murine model of reduced Fbxo7 expression to test its physiological role in multiple tissues and found that these mice displayed a pronounced thymic hypoplasia. Further analysis revealed that Fbxo7 differentially affected proliferation and apoptosis of thymocytes at various stages of differentiation in the thymus and also mature T-cell function and proliferation in the periphery. Paradoxically, Fbxo7-deficient immature thymocytes failed to undergo expansion in the thymus due to a lack of Cdk6 activity, while mature T cells showed enhanced proliferative capacity upon T-cell receptor engagement due to reduced p27 levels. Our studies reveal differential cell cycle regulation by Fbxo7 at different stages in T-cell development.
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Affiliation(s)
- Shachi P Patel
- Department of Pathology, University of Cambridge, Cambridge, UK
| | | | - Sarah Gibbs
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Anne Cooke
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Heike Laman
- Department of Pathology, University of Cambridge, Cambridge, UK.
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27
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Gsk3β and Tomm20 are substrates of the SCFFbxo7/PARK15 ubiquitin ligase associated with Parkinson's disease. Biochem J 2016; 473:3563-3580. [PMID: 27503909 PMCID: PMC5260939 DOI: 10.1042/bcj20160387] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/08/2016] [Indexed: 12/15/2022]
Abstract
Fbxo7 is a clinically relevant F-box protein, associated with both cancer and Parkinson's disease (PD). Additionally, SNPs within FBXO7 are correlated with alterations in red blood cell parameters. Point mutations within FBXO7 map within specific functional domains, including near its F-box domain and its substrate recruiting domains, suggesting that deficiencies in SCFFbxo7/PARK15 ubiquitin ligase activity are mechanistically linked to early-onset PD. To date, relatively few substrates of the ligase have been identified. These include HURP (hepatoma up-regulated protein), whose ubiquitination results in proteasome-mediated degradation, and c-IAP1 (inhibitor of apoptosis protein 1), TNF receptor-associated factor 2 (TRAF2), and NRAGE, which are not destabilized as a result of ubiquitination. None of these substrates have been linked directly to PD, nor has it been determined whether they would directly engage neuronal cell death pathways. To discover ubiquitinated substrates of SCFFbxo7 implicated more directly in PD aetiology, we conducted a high-throughput screen using protein arrays to identify new candidates. A total of 338 new targets were identified and from these we validated glycogen synthase kinase 3β (Gsk3β), which can phosphorylate α-synuclein, and translocase of outer mitochondrial membrane 20 (Tomm20), a mitochondrial translocase that, when ubiquitinated, promotes mitophagy, as SCFFbxo7 substrates both in vitro and in vivo. Ubiquitin chain restriction analyses revealed that Fbxo7 modified Gsk3β using K63 linkages. Our results indicate that Fbxo7 negatively regulates Gsk3β activity, rather than its levels or localization. In addition, Fbxo7 ubiquitinated Tomm20, and its levels correlated with Fbxo7 expression, indicating a stabilizing effect. None of the PD-associated mutations in Fbxo7 impaired Tomm20 ubiquitination. Our findings demonstrate that SCFFbxo7 has an impact directly on two proteins implicated in pathological processes leading to PD.
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Vingill S, Brockelt D, Lancelin C, Tatenhorst L, Dontcheva G, Preisinger C, Schwedhelm-Domeyer N, Joseph S, Mitkovski M, Goebbels S, Nave KA, Schulz JB, Marquardt T, Lingor P, Stegmüller J. Loss of FBXO7 (PARK15) results in reduced proteasome activity and models a parkinsonism-like phenotype in mice. EMBO J 2016; 35:2008-25. [PMID: 27497298 DOI: 10.15252/embj.201593585] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 07/07/2016] [Indexed: 11/09/2022] Open
Abstract
Mutations in the FBXO7 (PARK15) gene have been implicated in a juvenile form of parkinsonism termed parkinsonian pyramidal syndrome (PPS), characterized by Parkinsonian symptoms and pyramidal tract signs. FBXO7 (F-box protein only 7) is a subunit of the SCF (SKP1/cullin-1/F-box protein) E3 ubiquitin ligase complex, but its relevance and function in neurons remain to be elucidated. Here, we report that the E3 ligase FBXO7-SCF binds to and ubiquitinates the proteasomal subunit PSMA2. In addition, we show that FBXO7 is a proteasome-associated protein involved in proteasome assembly. In FBXO7 knockout mice, we find reduced proteasome activity and early-onset motor deficits together with premature death. In addition, we demonstrate that NEX (neuronal helix-loop-helix protein-1)-Cre-induced deletion of the FBXO7 gene in forebrain neurons or the loss of FBXO7 in tyrosine hydroxylase (TH)-positive neurons results in motor defects, reminiscent of the phenotype in PARK15 patients. Taken together, our study establishes a vital role for FBXO7 in neurons, which is required for proper motor control and accentuates the importance of FBXO7 in proteasome function.
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Affiliation(s)
- Siv Vingill
- Cellular and Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany Neuroscience, International Max Planck Research School, Göttingen, Germany
| | - David Brockelt
- Cellular and Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany Neuroscience, International Max Planck Research School, Göttingen, Germany
| | | | - Lars Tatenhorst
- Neurology, University Medical Center, Göttingen, Germany Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CMPB), Göttingen, Germany
| | - Guergana Dontcheva
- Cellular and Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany Neuroscience, International Max Planck Research School, Göttingen, Germany Department of Neurology, University Hospital, RWTH Aachen, Aachen, Germany
| | - Christian Preisinger
- Proteomics Facility, Interdisciplinary Center for Clinical Research (IZKF) Aachen, Medical Faculty, RWTH Aachen, Aachen, Germany
| | - Nicola Schwedhelm-Domeyer
- Cellular and Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sabitha Joseph
- Cellular and Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany Neuroscience, International Max Planck Research School, Göttingen, Germany Department of Neurology, University Hospital, RWTH Aachen, Aachen, Germany
| | - Miso Mitkovski
- Light Microscopy Facility, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sandra Goebbels
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CMPB), Göttingen, Germany Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jörg B Schulz
- Department of Neurology, University Hospital, RWTH Aachen, Aachen, Germany
| | - Till Marquardt
- European Neuroscience Institute (ENI), Göttingen, Germany Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CMPB), Göttingen, Germany Section Neurobiological Research, Department of Neurology, University Hospital, RWTH Aachen, Aachen, Germany
| | - Paul Lingor
- Neurology, University Medical Center, Göttingen, Germany Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CMPB), Göttingen, Germany
| | - Judith Stegmüller
- Cellular and Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CMPB), Göttingen, Germany Department of Neurology, University Hospital, RWTH Aachen, Aachen, Germany
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Hussain M, Lu Y, Liu YQ, Su K, Zhang J, Liu J, Zhou GB. Skp1: Implications in cancer and SCF-oriented anti-cancer drug discovery. Pharmacol Res 2016; 111:34-42. [PMID: 27238229 DOI: 10.1016/j.phrs.2016.05.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 04/28/2016] [Accepted: 05/25/2016] [Indexed: 12/29/2022]
Abstract
In the last decade, the ubiquitin proteasome system (UPS), in general, and E3 ubiquitin ligases, in particular, have emerged as valid drug targets for the development of novel anti-cancer therapeutics. Cullin RING Ligases (CRLs), which can be classified into eight groups (CRL1-8) and comprise approximately 200 members, represent the largest family of E3 ubiquitin ligases which facilitate the ubiquitination-derived proteasomal degradation of a myriad of functionally and structurally diverse substrates. S phase kinase-associated protein 1 (Skp1)-Cullin1-F-Box protein (SCF) complexes are the best characterized among CRLs, which play crucial roles in numerous cellular processes and physiological dysfunctions, such as in cancer biology. Currently, there is growing interest in developing SCF-targeting anti-cancer therapies for clinical application. Indeed, the research in this field has seen some progress in the form of cullin neddylation- and Skp2-inhibitors. However, it still remains an underdeveloped area and needs to design new strategies for developing improved form of therapy. In this review, we venture a novel strategy that rational pharmacological targeting of Skp1, a central regulator of SCF complexes, may provide a novel avenue for SCF-oriented anti-cancer therapy, expected: (i) to simultaneously address the critical roles that multiple SCF oncogenic complexes play in cancer biology, (ii) to selectively target cancer cells with minimal normal cell toxicity, and (iii) to offer multiple chemical series, via therapeutic interventions at the Skp1 binding interfaces in SCF complex, thereby maximizing chances of success for drug discovery. In addition, we also discuss the challenges that might be posed regarding rational pharmacological interventions against Skp1.
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Affiliation(s)
- Muzammal Hussain
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangzhou, 510530, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Yongzhi Lu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangzhou, 510530, PR China
| | - Yong-Qiang Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Kai Su
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangzhou, 510530, PR China; School of Life Sciences, University of Science and Technology of China, Hefei, 230000, PR China
| | - Jiancun Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangzhou, 510530, PR China; State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, PR China
| | - Jinsong Liu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangzhou, 510530, PR China.
| | - Guang-Biao Zhou
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China.
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Zheng N, Zhou Q, Wang Z, Wei W. Recent advances in SCF ubiquitin ligase complex: Clinical implications. Biochim Biophys Acta Rev Cancer 2016; 1866:12-22. [PMID: 27156687 DOI: 10.1016/j.bbcan.2016.05.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/09/2022]
Abstract
F-box proteins, which are subunit recruiting modules of SCF (SKP1-Cullin 1-F-box protein) E3 ligase complexes, play critical roles in the development and progression of human malignancies through governing multiple cellular processes including cell proliferation, apoptosis, invasion and metastasis. Moreover, there are emerging studies that lead to the development of F-box proteins inhibitors with promising therapeutic potential. In this article, we describe how F-box proteins including but not restricted to well-established Fbw7, Skp2 and β-TRCP, are involved in tumorigenesis. However, in-depth investigation is required to further explore the mechanism and the physiological contribution of undetermined F-box proteins in carcinogenesis. Lastly, we suggest that targeting F-box proteins could possibly open new avenues for the treatment and prevention of human cancers.
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Affiliation(s)
- Nana Zheng
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Quansheng Zhou
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Zhiwei Wang
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China; Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA 02215, USA.
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA 02215, USA.
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31
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Zhou ZD, Sathiyamoorthy S, Angeles DC, Tan EK. Linking F-box protein 7 and parkin to neuronal degeneration in Parkinson's disease (PD). Mol Brain 2016; 9:41. [PMID: 27090516 PMCID: PMC4835861 DOI: 10.1186/s13041-016-0218-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 04/06/2016] [Indexed: 02/01/2023] Open
Abstract
Mutations of F-box protein 7 (FBXO7) and Parkin, two proteins in ubiquitin-proteasome system (UPS), are both implicated in pathogenesis of dopamine (DA) neuron degeneration in Parkinson's disease (PD). Parkin is a HECT/RING hybrid ligase that physically receives ubiquitin on its catalytic centre and passes ubiquitin onto its substrates, whereas FBXO7 is an adaptor protein in Skp-Cullin-F-box (SCF) SCF(FBXO7) ubiquitin E3 ligase complex to recognize substrates and mediate substrates ubiquitination by SCF(FBXO7) E3 ligase. Here, we discuss the overlapping pathophysiologic mechanisms and clinical features linking Parkin and FBXO7 with autosomal recessive PD. Both proteins play an important role in neuroprotective mitophagy to clear away impaired mitochondria. Parkin can be recruited to impaired mitochondria whereas cellular stress can promote FBXO7 mitochondrial translocation. PD-linked FBXO7 can recruit Parkin into damaged mitochondria and facilitate its aggregation. WT FBXO7, but not PD-linked FBXO7 mutants can rescue DA neuron degeneration in Parkin null Drosophila. A better understanding of the common pathophysiologic mechanisms of these two proteins could unravel specific pathways for targeted therapy in PD.
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Affiliation(s)
- Zhi Dong Zhou
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore. .,Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857, Singapore.
| | - Sushmitha Sathiyamoorthy
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
| | - Dario C Angeles
- Department of Neurology, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore
| | - Eng King Tan
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore. .,Department of Neurology, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore. .,Signature Research Program in Neuroscience and Behavioural Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857, Singapore.
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Zheng N, Wang Z, Wei W. Ubiquitination-mediated degradation of cell cycle-related proteins by F-box proteins. Int J Biochem Cell Biol 2016; 73:99-110. [PMID: 26860958 PMCID: PMC4798898 DOI: 10.1016/j.biocel.2016.02.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 02/06/2023]
Abstract
F-box proteins, subunits of SKP1-cullin 1-F-box protein (SCF) type of E3 ubiquitin ligase complexes, have been validated to play a crucial role in governing various cellular processes such as cell cycle, cell proliferation, apoptosis, migration, invasion and metastasis. Recently, a wealth of evidence has emerged that F-box proteins is critically involved in tumorigenesis in part through governing the ubiquitination and subsequent degradation of cell cycle proteins, and dysregulation of this process leads to aberrant cell cycle progression and ultimately, tumorigenesis. Therefore, in this review, we describe the critical role of F-box proteins in the timely regulation of cell cycle. Moreover, we discuss how F-box proteins involve in tumorigenesis via targeting cell cycle-related proteins using biochemistry studies, engineered mouse models, and pathological gene alternations. We conclude that inhibitors of F-box proteins could have promising therapeutic potentials in part through controlling of aberrant cell cycle progression for cancer therapies.
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Affiliation(s)
- Nana Zheng
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, The First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Zhiwei Wang
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, The First Affiliated Hospital, Soochow University, Suzhou 215123, China; Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, USA.
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, USA.
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33
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Uddin S, Bhat AA, Krishnankutty R, Mir F, Kulinski M, Mohammad RM. Involvement of F-BOX proteins in progression and development of human malignancies. Semin Cancer Biol 2016; 36:18-32. [PMID: 26410033 DOI: 10.1016/j.semcancer.2015.09.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 09/15/2015] [Accepted: 09/15/2015] [Indexed: 12/13/2022]
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Heo J, Eki R, Abbas T. Deregulation of F-box proteins and its consequence on cancer development, progression and metastasis. Semin Cancer Biol 2015; 36:33-51. [PMID: 26432751 DOI: 10.1016/j.semcancer.2015.09.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 09/25/2015] [Accepted: 09/25/2015] [Indexed: 01/28/2023]
Abstract
F-box proteins are substrate receptors of the SCF (SKP1-Cullin 1-F-box protein) E3 ubiquitin ligase that play important roles in a number of physiological processes and activities. Through their ability to assemble distinct E3 ubiquitin ligases and target key regulators of cellular activities for ubiquitylation and degradation, this versatile group of proteins is able to regulate the abundance of cellular proteins whose deregulated expression or activity contributes to disease. In this review, we describe the important roles of select F-box proteins in regulating cellular activities, the perturbation of which contributes to the initiation and progression of a number of human malignancies.
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Affiliation(s)
- Jinho Heo
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, USA
| | - Rebeka Eki
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, USA; Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Tarek Abbas
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, USA; Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA; Center for Cell Signaling, University of Virginia, Charlottesville, VA, USA.
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Randle SJ, Laman H. F-box protein interactions with the hallmark pathways in cancer. Semin Cancer Biol 2015; 36:3-17. [PMID: 26416465 DOI: 10.1016/j.semcancer.2015.09.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 09/18/2015] [Accepted: 09/23/2015] [Indexed: 12/24/2022]
Abstract
F-box proteins (FBP) are the substrate specifying subunit of Skp1-Cul1-FBP (SCF)-type E3 ubiquitin ligases and are responsible for directing the ubiquitination of numerous proteins essential for cellular function. Due to their ability to regulate the expression and activity of oncogenes and tumour suppressor genes, FBPs themselves play important roles in cancer development and progression. In this review, we provide a comprehensive overview of FBPs and their targets in relation to their interaction with the hallmarks of cancer cell biology, including the regulation of proliferation, epigenetics, migration and invasion, metabolism, angiogenesis, cell death and DNA damage responses. Each cancer hallmark is revealed to have multiple FBPs which converge on common signalling hubs or response pathways. We also highlight the complex regulatory interplay between SCF-type ligases and other ubiquitin ligases. We suggest six highly interconnected FBPs affecting multiple cancer hallmarks, which may prove sensible candidates for therapeutic intervention.
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Affiliation(s)
- Suzanne J Randle
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Heike Laman
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom.
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36
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Zhou ZD, Xie SP, Sathiyamoorthy S, Saw WT, Sing TY, Ng SH, Chua HPH, Tang AMY, Shaffra F, Li Z, Wang H, Ho PGH, Lai MKP, Angeles DC, Lim TM, Tan EK. F-box protein 7 mutations promote protein aggregation in mitochondria and inhibit mitophagy. Hum Mol Genet 2015; 24:6314-30. [PMID: 26310625 DOI: 10.1093/hmg/ddv340] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 08/17/2015] [Indexed: 11/14/2022] Open
Abstract
The mutations of F-box protein 7 (FBXO7) gene (T22M, R378G and R498X) are associated with a severe form of autosomal recessive juvenile-onset Parkinson's disease (PD) (PARK 15). Here we demonstrated that wild-type (WT) FBXO7 is a stress response protein and it can play both cytoprotective and neurotoxic roles. The WT FBXO7 protein is vital to cell mitophagy and can facilitate mitophagy to protect cells, whereas mutant FBXO7 inhibits mitophagy. Upon stress, the endogenous WT FBXO7 gets up-regulated, concentrates into mitochondria and forms FBXO7 aggregates in mitochondria. However, FBXO7 mutations aggravate deleterious FBXO7 aggregation in mitochondria. The FBXO7 aggregation and toxicity can be alleviated by Proline, glutathione (GSH) and coenzyme Q10, whereas deleterious FBXO7 aggregation in mitochondria can be aggravated by prohibitin 1 (PHB1), a mitochondrial protease inhibitor. The overexpression of WT FBXO7 could lead to FBXO7 protein aggregation and dopamine neuron degeneration in transgenic Drosophila heads. The elevated FBXO7 expression and aggregation were identified in human fibroblast cells from PD patients. FBXO7 can also form aggregates in brains of PD and Alzheimer's disease. Our study provides novel pathophysiologic insights and suggests that FBXO7 may be a potential therapeutic target in FBXO7-linked neuron degeneration in PD.
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Affiliation(s)
- Zhi Dong Zhou
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore, Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, Singapore
| | - Shao Ping Xie
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | | | - Wuan Ting Saw
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Tan Ye Sing
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Shin Hui Ng
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Heidi Pek Hup Chua
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Alyssa Mei Yan Tang
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Fathima Shaffra
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Zeng Li
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Hongyan Wang
- Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, Singapore
| | - Patrick Ghim Hoe Ho
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore
| | - Mitchell Kim Peng Lai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Dario C Angeles
- Department of Neurology, Singapore General Hospital, Outram Road, Singapore, Singapore and
| | - Tit Meng Lim
- Department of Biological Science, National University of Singapore, 14 Science Drive 4, Singapore, Singapore
| | - Eng-King Tan
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, Singapore, Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, Singapore, Department of Neurology, Singapore General Hospital, Outram Road, Singapore, Singapore and
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Liu QX, Zheng H, Deng XF, Zhou D, Dai JG. Status of the Parkinson's disease gene family expression in non-small-cell lung cancer. World J Surg Oncol 2015; 13:238. [PMID: 26245297 PMCID: PMC4527104 DOI: 10.1186/s12957-015-0646-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 07/14/2015] [Indexed: 02/08/2023] Open
Abstract
Background The purpose of this study is to detect the Parkinson’s disease gene family mRNA relative expression in the non-small-cell lung cancer (NSCLC) tumor tissue and analyze the association between tumor characteristics and the Parkinson’s disease gene family. Methods Tumor tissue and tumor-adjacent tissue of 114 NSCLC patients were collected and SYBR quantitative analysis was used to detect the relative expression level of nine Parkinson’s disease gene mRNAs. Then, paired sample test, two-sided Student’s t-test, or two-sided Wilcoxon rank sum test was performed to analyze the mRNA relative expression level of nine Parkinson’s disease gene mRNAs in different gender, tumor histology, and tumor stage. Results Overexpression in the tumors was detected in 46/114 (40.35 %) PARK1/4, 74/114 (64.91 %) PARK2, 104/114 (91.23 %) PARK5, 95/114 (83.33 %) PARK6, 80/114 (70.18 %) PARK7, 55/114 (48.25 %) PARK8, 100/114 (87.72 %) PARK9, 55/114 (48.25 %) PARK15, and 99/114 (86.84 %) glucocerebrosidase (GBA). Five genes PARK5 (91.23 %), PARK6 (83.33 %), PARK7 (70.18 %), PARK9 (87.72 %), and GBA (86.84 %) were supposed to be overexpressed in the lung tumor tissues compared with tumor-adjacent tissues. There was no significant difference in PARK1/4, PARK2, PARK5, PARK9, and GBA mRNA expression by different tumor stage, whereas, PARK6, PARK7, PARK8, and PARK15 mRNA expression were found to have significant difference in the comparison of different tumor stages. The expression of PARK6 (P = 0.01, P = 0.03) and PARK15 (P < 0.001, P < 0.001) were significantly higher in stages I and II when compared with stage III, respectively. NSCLC patients in stage I showed the higher expression PARK7 compared to the patients in stage II (P = 0.003). Conclusions The high expression of PARK6, PARK7, and PARK15 might lead to the occurrence of a primary NSCLC tumor, and the tumor with a decreasing expression of these three genes tends to be stages II and III. The results of our study indicate that the Parkinson’s disease gene family may be a potential marker for the prediction of NSCLC. Electronic supplementary material The online version of this article (doi:10.1186/s12957-015-0646-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Quan Xing Liu
- Department of Thoracic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
| | - Hong Zheng
- Institute of Immunology of PLA, Third Military Medical University, Chongqing, 400037, China.
| | - Xu Feng Deng
- Department of Thoracic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
| | - Dong Zhou
- Department of Thoracic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
| | - Ji Gang Dai
- Department of Thoracic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
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38
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Randle SJ, Nelson DE, Patel SP, Laman H. Defective erythropoiesis in a mouse model of reduced Fbxo7 expression due to decreased p27 expression. J Pathol 2015; 237:263-72. [PMID: 26095538 PMCID: PMC4583784 DOI: 10.1002/path.4571] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/26/2015] [Accepted: 06/09/2015] [Indexed: 01/04/2023]
Abstract
During the final stages of erythropoiesis, lineage-restricted progenitors mature over three to five cell divisions, culminating with withdrawal from the cell cycle and the loss of most organelles, including mitochondria and nuclei. Recent genome-wide association studies in human populations have associated several SNPs near or within FBXO7 with erythrocyte phenotypes. Fbxo7 encodes a multi-functional F-box protein known to bind p27 and participate in selective mitophagy. One SNP causes an amino acid substitution (Met115Ile) and is associated with smaller erythrocytes. We find that the less common IIe115 allele of Fbxo7 binds less efficiently to p27, and cells expressing this allele proliferate faster than cells expressing Met115. We show that an erythroleukaemic cell line with reduced Fbxo7 expression fails to stabilize p27 levels, exit the cell cycle, and produce haemoglobin. In addition, mice deficient in Fbxo7 expression are anaemic due to a reduction in erythrocyte numbers, and this is associated with lower p27 levels, increased numbers of late-stage erythroblasts with greater than 2N DNA content, and delayed mitophagy during terminal differentiation. Collectively, these data support an important physiological, cell cycle regulatory role for Fbxo7 during erythropoiesis. © 2015 Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
| | - David E Nelson
- University of Cambridge, Department of Pathology, Cambridge, UK
| | - Shachi P Patel
- University of Cambridge, Department of Pathology, Cambridge, UK
| | - Heike Laman
- University of Cambridge, Department of Pathology, Cambridge, UK
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39
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Dikopoltsev E, Foltyn VN, Zehl M, Jensen ON, Mori H, Radzishevsky I, Wolosker H. FBXO22 protein is required for optimal synthesis of the N-methyl-D-aspartate (NMDA) receptor coagonist D-serine. J Biol Chem 2014; 289:33904-15. [PMID: 25336657 DOI: 10.1074/jbc.m114.618405] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
d-Serine is a physiological activator of NMDA receptors (NMDARs) in the nervous system that mediates several NMDAR-mediated processes ranging from normal neurotransmission to neurodegeneration. d-Serine is synthesized from l-serine by serine racemase (SR), a brain-enriched enzyme. However, little is known about the regulation of d-serine synthesis. We now demonstrate that the F-box only protein 22 (FBXO22) interacts with SR and is required for optimal d-serine synthesis in cells. Although FBXO22 is classically associated with the ubiquitin system and is recruited to the Skip1-Cul1-F-box E3 complex, SR interacts preferentially with free FBXO22 species. In vivo ubiquitination and SR half-life determination indicate that FBXO22 does not target SR to the proteasome system. FBXO22 primarily affects SR subcellular localization and seems to increase d-serine synthesis by preventing the association of SR to intracellular membranes. Our data highlight an atypical role of FBXO22 in enhancing d-serine synthesis that is unrelated to its classical effects as a component of the ubiquitin-proteasome degradation pathway.
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Affiliation(s)
- Elena Dikopoltsev
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Veronika N Foltyn
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Martin Zehl
- the Department of Pharmacognosy, University of Vienna, 1090 Vienna, Austria
| | - Ole N Jensen
- the Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark, and
| | - Hisashi Mori
- the Department of Molecular Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan
| | - Inna Radzishevsky
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Herman Wolosker
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel,
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40
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Shang J, Huang X, Du Z. The FP domains of PI31 and Fbxo7 have the same protein fold but very different modes of protein-protein interaction. J Biomol Struct Dyn 2014; 33:1528-38. [PMID: 25266262 DOI: 10.1080/07391102.2014.963675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Fbxo7 and PI31 contain a conserved FP domain that mediates the homo-/hetero-dimerization of the proteins. The PI31 FP domain may also interact with the F-box motif in Fbxo7. The FP domain-mediated protein-protein interactions are important for the functions of Fbxo7 and PI31. The crystal structures of the Fbxo7 and PI31 FP domains were determined previously, showing that a C-terminal helix in the Fbxo7 FP domain was not present in the PI31 FP domain. Here, we determine the crystal structure of the PI31 FP domain using a longer protein construct. The structure is comparable to the Fbxo7 FP domain (including the C-terminal helix), indicating that the two FP domains share the same global fold. However, the FP domains also harbor their own characteristic structural features, mainly in the longest loop (which has a largely fixed conformation due to extensive hydrogen bonding and hydrophobic interactions) and the C-terminal end regions. The crystal structures also reveal fundamental differences in the modes of protein-protein interactions mediated by the two FP domains: the PI31 FP domain utilizes either an α interface or β interface for homodimeric interaction, whereas the Fbxo7 FP domain utilizes an αβ interface. We perform modeling studies to show that the domain-specific structural features may dictate specific modes of inter-domain interactions. We propose that a heterodimeric interaction would be mediated by an αβ interface consisting of the α-helical and β-sheet surfaces of the Fbxo7 and PI31 FP domains, respectively. We also discuss the structural/functional significance of various modes of FP domain-mediated protein-protein interactions.
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Affiliation(s)
- Jinsai Shang
- a Department of Chemistry and Biochemistry , Southern Illinois University at Carbondale , Carbondale , IL 62901 , USA
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41
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Li LP, Wu WJ, Sun DAY, Xie ZY, Ma YC, Zhao YG. miR-449a and CDK6 in gastric carcinoma. Oncol Lett 2014; 8:1533-1538. [PMID: 25202363 PMCID: PMC4156198 DOI: 10.3892/ol.2014.2370] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 04/03/2014] [Indexed: 01/05/2023] Open
Abstract
The present study aimed to identify the association between microRNA (miR/miRNA)-449a, the cyclin-dependent kinase (CDK)6 protein and gastric carcinoma, and discuss the effect of miR-449a on the expression of the CDK6 protein. Quantitative (q)PCR and western blot analysis were used to analyze the expression of the miR-449a and the CDK6 protein in gastric carcinoma and tumor-adjacent normal tissues. The real-time cell analyzer and the DAPI staining test were used to monitor the different miR-449a levels regulating the proliferation and apoptosis of the MGC-803 cell line. Immunofluorescence and western blot analyses were used to detect the expression level of the CDK6 protein in the cells of the miR-449a upregulation and downregulation groups, and a control group. A scratch test was used to study the effects of miR-449a expression on migration and invasion. It was found that the expression of miR-449a was downregulated and the expression of CDK6 protein was upregulated in gastric carcinoma tissue. The level of MGC-803 cell proliferation was decreased and the apoptosis level was increased by the upregulation of miR-449a expression, and the opposite effect was shown by the downregulation of expression. The expression of the CDK6 protein in the MGC-803 cells was downregulated by upregulating the expression of miR-449a. The distance of the scratch was shortened markedly after 12 h by downregulating the expression of miR-449a in the MGC-803 cells. The present study identified that a lower expression level of miR-449 and a higher expression level of CDK6 may contribute to the occurrence and development of gastric cancer. Furthermore, it was shown that miR-449a is able to regulate the expression of the CDK6 protein.
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Affiliation(s)
- Li-Ping Li
- Department of Gastroenterology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Wei-Jing Wu
- Department of Respiratory Medicine, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian 362000, P.R. China
| | - DA-Yong Sun
- Department of Gastroenterology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Zi-Ying Xie
- Department of Gastroenterology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Yan-Chun Ma
- Department of Gastroenterology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Ya-Gang Zhao
- Department of Gastroenterology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
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42
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Abstract
F-box proteins, which are the substrate-recognition subunits of SKP1-cullin 1-F-box protein (SCF) E3 ligase complexes, have pivotal roles in multiple cellular processes through ubiquitylation and subsequent degradation of target proteins. Dysregulation of F-box protein-mediated proteolysis leads to human malignancies. Notably, inhibitors that target F-box proteins have shown promising therapeutic potential, urging us to review the current understanding of how F-box proteins contribute to tumorigenesis. As the physiological functions for many of the 69 putative F-box proteins remain elusive, additional genetic and mechanistic studies will help to define the role of each F-box protein in tumorigenesis, thereby paving the road for the rational design of F-box protein-targeted anticancer therapies.
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Affiliation(s)
- Zhiwei Wang
- 1] Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA. [2] The Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, P. R. China. [3]
| | - Pengda Liu
- 1] Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA. [2]
| | - Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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43
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Shang J, Wang G, Yang Y, Huang X, Du Z. Structure of the FP domain of Fbxo7 reveals a novel mode of protein-protein interaction. ACTA ACUST UNITED AC 2013; 70:155-64. [PMID: 24419388 DOI: 10.1107/s1399004713025820] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 09/18/2013] [Indexed: 01/17/2023]
Abstract
The FP (Fbxo7/PI31) domains found in the F-box protein Fbxo7 and the proteasome inhibitor PI31 mediate the homodimerization and heterodimerization of Fbxo7 and PI31. Fbxo7 is the substrate-recognition subunit of the SCF(Fbxo7) (Skp1-Cul1-F-box protein) E3 ubiquitin ligase that catalyzes the ubiquitination of hepatoma up-regulated protein (HURP) and inhibitor of apoptosis protein (IAP). Fbxo7 also interacts with proteins that are not substrates of the ubiquitin proteasome system, such as Cdk6 and PI31. Here, the crystal structure of the Fbxo7 FP domain is reported at 2.0 Å resolution. The Fbxo7 FP domain adopts an α/β-fold similar to that of the PI31 FP domain. However, an α-helix and three β-strands in the Fbxo7 FP domain are longer than their counterparts in the PI31 FP domain. The differences in these secondary-structural elements are spatially clustered to define a more structured and extended C-terminal end of the Fbxo7 FP domain. The two FP domains also differ substantially in the length and conformation of the longest connecting loop. More importantly, structural differences between the two FP domains lead to drastically different modes of inter-domain protein-protein interaction. The inter-domain interface of the Fbxo7 FP domain is defined by the α-helical surface in one protomer and the β-sheet surface in the other protomer, whereas for the PI31 domain it is defined by either the α-helical surfaces or the β-sheet surfaces in both protomers. The inter-domain interaction of the Fbxo7 FP domain is much more extensive, featuring a larger contact surface area, better shape complementarity and more hydrophobic and hydrogen-bonding interactions. The Fbxo7 FP domain also has the potential to bind two protein partners simultaneously using the α-helical and β-sheet surfaces. The results of this structural study provide critical insights into how Fbxo7 may dimerize (or multimerize) and interact with other regulatory proteins via the FP domain.
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Affiliation(s)
- Jinsai Shang
- Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL 62901, USA
| | - Guan Wang
- Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL 62901, USA
| | - Yang Yang
- Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL 62901, USA
| | - Xiaolan Huang
- Computer Science, Southern Illinois University, 1000 Faner Drive, Carbondale, IL 62901, USA
| | - Zhihua Du
- Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL 62901, USA
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44
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Kohrt D, Crary J, Zimmer M, Patrick AN, Ford HL, Hinds PW, Grossel MJ. CDK6 binds and promotes the degradation of the EYA2 protein. Cell Cycle 2013; 13:62-71. [PMID: 24196439 PMCID: PMC3925736 DOI: 10.4161/cc.26755] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cyclin-dependent kinase 6 (Cdk6) is a D-Cyclin-activated kinase that is directly involved in driving the cell cycle through inactivation of pRB in G1 phase. Increasingly, evidence suggests that CDK6, while directly driving the cell cycle, may only be essential for proliferation of specialized cell types, agreeing with the notion that CDK6 also plays an important role in differentiation. Here, evidence is presented that CDK6 binds to and promotes degradation of the EYA2 protein. The EYA proteins are a family of proteins that activate genes essential for the development of multiple organs, regulate cell proliferation, and are misregulated in several types of cancer. This interaction suggests that CDK6 regulates EYA2 activity, a mechanism that could be important in development and in cancer.
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Affiliation(s)
- Dawn Kohrt
- Department of Biology; Connecticut College; New London, CT USA
| | - Jennifer Crary
- Department of Biology; Connecticut College; New London, CT USA; Department of Developmental, Molecular, and Chemical Biology; Tufts University School of Medicine, and Molecular Oncology Research Institute; Tufts Medical Center; Boston, MA USA
| | - Marc Zimmer
- Department of Chemistry; Connecticut College; New London, CT USA
| | - Aaron N Patrick
- Department of Pharmacology; University of Colorado School of Medicine; Aurora, CO USA
| | - Heide L Ford
- Department of Pharmacology; University of Colorado School of Medicine; Aurora, CO USA
| | - Philip W Hinds
- Department of Developmental, Molecular, and Chemical Biology; Tufts University School of Medicine, and Molecular Oncology Research Institute; Tufts Medical Center; Boston, MA USA
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45
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Nelson DE, Randle SJ, Laman H. Beyond ubiquitination: the atypical functions of Fbxo7 and other F-box proteins. Open Biol 2013; 3:130131. [PMID: 24107298 PMCID: PMC3814724 DOI: 10.1098/rsob.130131] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
F-box proteins (FBPs) are substrate-recruiting subunits of Skp1-cullin1-FBP (SCF)-type E3 ubiquitin ligases. To date, 69 FBPs have been identified in humans, but ubiquitinated substrates have only been identified for a few, with the majority of FBPs remaining ‘orphans’. In recent years, a growing body of work has identified non-canonical, SCF-independent roles for about 12% of the human FBPs. These atypical FBPs affect processes as diverse as transcription, cell cycle regulation, mitochondrial dynamics and intracellular trafficking. Here, we provide a general review of FBPs, with a particular emphasis on these expanded functions. We review Fbxo7 as an exemplar of this special group as it has well-defined roles in both SCF and non-SCF complexes. We review its function as a cell cycle regulator, via its ability to stabilize p27 protein and Cdk6 complexes, and as a proteasome regulator, owing to its high affinity binding to PI31. We also highlight recent advances in our understanding of Fbxo7 function in Parkinson's disease, where it functions in the regulation of mitophagy with PINK1 and Parkin. We postulate that a few extraordinary FBPs act as platforms that seamlessly segue their canonical and non-canonical functions to integrate different cellular pathways and link their regulation.
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Affiliation(s)
- David E Nelson
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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46
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Shang J, Wang G, Yang Y, Huang X, Du Z. Expression, purification and crystallization of the FP domain of the human F-box protein Fbxo7. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1097-9. [PMID: 24100556 DOI: 10.1107/s1744309113023154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 08/17/2013] [Indexed: 11/11/2022]
Abstract
Fbxo7 is a conserved protein in higher eukaryotes that belongs to the F-box protein family. Fbxo7 is the substrate-recognition component of the SCFFbxo7 (Skp1-Cul1-Fbox protein) E3 ubiquitin ligase. Besides the F-box motif, Fbxo7 also contains a C-terminal proline-rich region, an N-terminal ubiquitin-like domain and a novel FP (Fbxo7/PI31) domain preceding the F-box motif. The FP domains of Fbxo7 and the PI31 proteasome inhibitor mediate interaction between the two proteins. For structure determination of the FP domain of Fxbo7, a protein construct (amino acids 181-335) corresponding to the FP domain was expressed, purified and crystallized. The native and selenomethionine-labeled proteins crystallized in different crystal forms. Native and single-wavelength anomalous dispersion data sets with diffraction to 2.1 and 2.0 Å resolution, respectively, have been collected and structure determination is in progress.
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Affiliation(s)
- Jinsai Shang
- Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL 62901, USA
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47
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Teixeira FR, Manfiolli AO, Soares CS, Baqui MMA, Koide T, Gomes MD. The F-box protein FBXO25 promotes the proteasome-dependent degradation of ELK-1 protein. J Biol Chem 2013; 288:28152-62. [PMID: 23940030 DOI: 10.1074/jbc.m113.504308] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
FBXO25 is one of the 69 known human F-box proteins that serve as specificity factors for a family of ubiquitin ligases composed of SKP1, Rbx1, Cullin1, and F-box protein (SCF1) that are involved in targeting proteins for degradation across the ubiquitin proteasome system. However, the substrates of most SCF E3 ligases remain unknown. Here, we applied an in chip ubiquitination screen using a human protein microarray to uncover putative substrates for the FBXO25 protein. Among several novel putative targets identified, the c-fos protooncogene regulator ELK-1 was characterized as the first endogenous substrate for SCF1(FBXO25) E3 ligase. FBXO25 interacted with and mediated the ubiquitination and proteasomal degradation of ELK-1 in HEK293T cells. In addition, FBXO25 overexpression suppressed induction of two ELK-1 target genes, c-fos and egr-1, in response to phorbol 12-myristate 13-acetate. Together, our findings show that FBXO25 mediates ELK-1 degradation through the ubiquitin proteasome system and thereby plays a role in regulating the activation of ELK-1 pathway in response to mitogens.
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48
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The Parkinson's disease-linked proteins Fbxo7 and Parkin interact to mediate mitophagy. Nat Neurosci 2013; 16:1257-65. [PMID: 23933751 PMCID: PMC3827746 DOI: 10.1038/nn.3489] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/05/2013] [Indexed: 01/03/2023]
Abstract
Compelling evidence indicates that two autosomal recessive Parkinson’s disease genes, PINK1 (PARK6) and Parkin (PARK2), co-operate to mediate the autophagic clearance of damaged mitochondria (mitophagy). Mutations in the F-box domain containing protein Fbxo7 (PARK15) also cause early onset autosomal recessive Parkinson’s disease by an unknown mechanism. Here we show that Fbxo7 participates in mitochondrial maintenance through direct interaction with PINK1 and Parkin and plays a role in Parkin-mediated mitophagy. Cells with reduced Fbxo7 expression show deficiencies in Parkin mitochondrial translocation, ubiquitination of mitofusin 1 and mitophagy. In Drosophila, ectopic overexpression of Fbxo7 rescued loss of Parkin supporting a functional relationship between the two proteins. Parkinson’s disease-causing mutations in Fbxo7 interfere with this process, emphasising the importance of mitochondrial dysfunction in Parkinson’s disease pathogenesis.
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Kuiken HJ, Egan DA, Laman H, Bernards R, Beijersbergen RL, Dirac AM. Identification of F-box only protein 7 as a negative regulator of NF-kappaB signalling. J Cell Mol Med 2013; 16:2140-9. [PMID: 22212761 PMCID: PMC3822984 DOI: 10.1111/j.1582-4934.2012.01524.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The nuclear factor κB (NF-κB) signalling pathway controls important cellular events such as cell proliferation, differentiation, apoptosis and immune responses. Pathway activation occurs rapidly upon TNFα stimulation and is highly dependent on ubiquitination events. Using cytoplasmic to nuclear translocation of the NF-κB transcription factor family member p65 as a read-out, we screened a synthetic siRNA library targeting enzymes involved in ubiquitin conjugation and de-conjugation for modifiers of regulatory ubiquitination events in NF-κB signalling. We identified F-box protein only 7 (FBXO7), a component of Skp, Cullin, F-box (SCF)-ubiquitin ligase complexes, as a negative regulator of NF-κB signalling. F-box protein only 7 binds to, and mediates ubiquitin conjugation to cIAP1 and TRAF2, resulting in decreased RIP1 ubiquitination and lowered NF-κB signalling activity.
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Affiliation(s)
- Hendrik J Kuiken
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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Maeda Y, Tsuchiya T, Hao H, Tompkins DH, Xu Y, Mucenski ML, Du L, Keiser AR, Fukazawa T, Naomoto Y, Nagayasu T, Whitsett JA. Kras(G12D) and Nkx2-1 haploinsufficiency induce mucinous adenocarcinoma of the lung. J Clin Invest 2012; 122:4388-400. [PMID: 23143308 DOI: 10.1172/jci64048] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 09/06/2012] [Indexed: 12/16/2022] Open
Abstract
Mucinous adenocarcinoma of the lung is a subtype of highly invasive pulmonary tumors and is associated with decreased or absent expression of the transcription factor NK2 homeobox 1 (NKX2-1; also known as TTF-1). Here, we show that haploinsufficiency of Nkx2-1 in combination with oncogenic Kras(G12D), but not with oncogenic EGFR(L858R), caused pulmonary tumors in transgenic mice that were phenotypically similar to human mucinous adenocarcinomas. Gene expression patterns distinguished tumor goblet (mucous) cells from nontumorigenic airway and intestinal goblet cells. Expression of NKX2-1 inhibited urethane and oncogenic Kras(G12D)-induced tumorigenesis in vivo. Haploinsufficiency of Nkx2-1 enhanced Kras(G12D)-mediated tumor progression, but reduced EGFR(L858R)-mediated progression. Genome-wide analysis of gene expression demonstrated that a set of genes induced in mucinous tumors was shared with genes induced in a nontumorigenic chronic lung disease, while a distinct subset of genes was specific to mucinous tumors. ChIP with massively parallel DNA sequencing identified a direct association of NKX2-1 with the genes induced in mucinous tumors. NKX2-1 associated with the AP-1 binding element as well as the canonical NKX2-1 binding element. NKX2-1 inhibited both AP-1 activity and tumor colony formation in vitro. These data demonstrate that NKX2-1 functions in a context-dependent manner in lung tumorigenesis and inhibits Kras(G12D)-driven mucinous pulmonary adenocarcinoma.
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Affiliation(s)
- Yutaka Maeda
- Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, USA
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