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George M, Masamba P, Iwalokun BA, Kappo AP. Zooming into the structure-function of RING finger proteins for anti-cancer therapeutic applications. Am J Cancer Res 2023; 13:2773-2789. [PMID: 37559981 PMCID: PMC10408477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 05/22/2023] [Indexed: 08/11/2023] Open
Abstract
Cancer is one of the most common and widely diagnosed diseases worldwide. With an increase in prevalence and incidence, many studies in cancer biology have been looking at the role pro-cancer proteins play. One of these proteins is the Really Interesting New Gene (RING), which has been studied extensively due to its structure and functions such as apoptosis, neddylation, and its role in ubiquitination. The RING domain is a cysteine-rich domain known to bind Cysteine and Histidine residues. It also binds two zinc ions that help stabilize the protein in various patterns, often with a 'cross-brace' topology. Different RING finger proteins have been studied and found to have suitable targets for developing anti-cancer therapeutics. These identified candidate proteins include Parkin, COP1, MDM2, BARD1, BRCA-1, PIRH2, c-CBL, SIAH1, RBX1 and RNF8. Inhibiting these candidate proteins provides opportunities for shutting down pathways associated with tumour development and metastasis.
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Affiliation(s)
- Mary George
- Molecular Biophysics and Structural Biology (MBSB) Group, Department of Biochemistry, Faculty of Science, University of Johannesburg, Auckland Park Kingsway CampusAuckland Park, Johannesburg, South Africa
| | - Priscilla Masamba
- Molecular Biophysics and Structural Biology (MBSB) Group, Department of Biochemistry, Faculty of Science, University of Johannesburg, Auckland Park Kingsway CampusAuckland Park, Johannesburg, South Africa
| | - Bamidele Abiodun Iwalokun
- Department of Molecular Biology and Biotechnology, Nigerian Institute of Medical Research (NIMR)Yaba, Lagos, Nigeria
| | - Abidemi Paul Kappo
- Molecular Biophysics and Structural Biology (MBSB) Group, Department of Biochemistry, Faculty of Science, University of Johannesburg, Auckland Park Kingsway CampusAuckland Park, Johannesburg, South Africa
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2
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Shen J, Wang Q, Mao Y, Gao W, Duan S. Targeting the p53 signaling pathway in cancers: Molecular mechanisms and clinical studies. MedComm (Beijing) 2023; 4:e288. [PMID: 37256211 PMCID: PMC10225743 DOI: 10.1002/mco2.288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 04/25/2023] [Accepted: 05/08/2023] [Indexed: 06/01/2023] Open
Abstract
Tumor suppressor p53 can transcriptionally activate downstream genes in response to stress, and then regulate the cell cycle, DNA repair, metabolism, angiogenesis, apoptosis, and other biological responses. p53 has seven functional domains and 12 splice isoforms, and different domains and subtypes play different roles. The activation and inactivation of p53 are finely regulated and are associated with phosphorylation/acetylation modification and ubiquitination modification, respectively. Abnormal activation of p53 is closely related to the occurrence and development of cancer. While targeted therapy of the p53 signaling pathway is still in its early stages and only a few drugs or treatments have entered clinical trials, the development of new drugs and ongoing clinical trials are expected to lead to the widespread use of p53 signaling-targeted therapy in cancer treatment in the future. TRIAP1 is a novel p53 downstream inhibitor of apoptosis. TRIAP1 is the homolog of yeast mitochondrial intermembrane protein MDM35, which can play a tumor-promoting role by blocking the mitochondria-dependent apoptosis pathway. This work provides a systematic overview of recent basic research and clinical progress in the p53 signaling pathway and proposes that TRIAP1 is an important therapeutic target downstream of p53 signaling.
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Affiliation(s)
- Jinze Shen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang ProvinceSchool of MedicineHangzhou City UniversityHangzhouZhejiangChina
| | - Qurui Wang
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang ProvinceSchool of MedicineHangzhou City UniversityHangzhouZhejiangChina
| | - Yunan Mao
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang ProvinceSchool of MedicineHangzhou City UniversityHangzhouZhejiangChina
| | - Wei Gao
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang ProvinceSchool of MedicineHangzhou City UniversityHangzhouZhejiangChina
| | - Shiwei Duan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang ProvinceSchool of MedicineHangzhou City UniversityHangzhouZhejiangChina
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3
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Chen C, Yang Y, Pan L, Xia W, Xu L, Hua B, Zhang Z, Miao M. Genome-Wide Identification of WD40 Proteins in Cucurbita maxima Reveals Its Potential Functions in Fruit Development. Genes (Basel) 2023; 14:genes14010220. [PMID: 36672961 PMCID: PMC9859561 DOI: 10.3390/genes14010220] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 01/02/2023] [Accepted: 01/09/2023] [Indexed: 01/18/2023] Open
Abstract
WD40 proteins, a super gene family in eukaryotes, are involved in multiple biological processes. Members of this family have been identified in several plants and shown to play key roles in various development processes, including acting as scaffolding molecules with other proteins. However, WD40 proteins have not yet been systematically analyzed and identified in Cucurbita maxima. In this study, 231 WD40 proteins (CmWD40s) were identified in C. maxima and classified into five clusters. Eleven subfamilies were identified based on different conserved motifs and gene structures. The CmWD40 genes were distributed in 20 chromosomes; 5 and 33 pairs of CmWD40s were distinguished as tandem and segmental duplications, respectively. Overall, 58 pairs of orthologous WD40 genes in C. maxima and Arabidopsis thaliana, and 56 pairs of orthologous WD40 genes in C. maxima and Cucumis sativus were matched. Numerous CmWD40s had diverse expression patterns in fruits, leaf, stem, and root. Several genes were involved in responses to NaCl. The expression pattern of CmWD40s suggested their key role in fruit development and abiotic stress response. Finally, we identified 14 genes which might be involved in fruit development. Our results provide valuable basis for further functional verification of CmWD40s in C. maxima.
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Affiliation(s)
- Chen Chen
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Yating Yang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Liu Pan
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Wenhao Xia
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Lanruoyan Xu
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Bing Hua
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Zhiping Zhang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Minmin Miao
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
- Correspondence:
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4
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A COP1-GATA2 axis suppresses AR signaling and prostate cancer. Proc Natl Acad Sci U S A 2022; 119:e2205350119. [PMID: 36251994 PMCID: PMC9618149 DOI: 10.1073/pnas.2205350119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Androgen receptor (AR) signaling is crucial for driving prostate cancer (PCa), the most diagnosed and the second leading cause of death in male patients with cancer in the United States. Androgen deprivation therapy is initially effective in most instances of AR-positive advanced or metastatic PCa. However, patients inevitably develop lethal castration-resistant PCa (CRPC), which is also resistant to the next-generation AR signaling inhibitors. Most CRPCs maintain AR expression, and blocking AR signaling remains a main therapeutic approach. GATA2 is a pioneer transcription factor emerging as a key therapeutic target for PCa because it promotes AR expression and activation. While directly inhibiting GATA2 transcriptional activity remains challenging, enhancing GATA2 degradation is a plausible therapeutic strategy. How GATA2 protein stability is regulated in PCa remains unknown. Here, we show that constitutive photomorphogenesis protein 1 (COP1), an E3 ubiquitin ligase, drives GATA2 ubiquitination at K419/K424 for degradation. GATA2 lacks a conserved [D/E](x)xxVP[D/E] degron but uses alternate BR1/BR2 motifs to bind COP1. By promoting GATA2 degradation, COP1 inhibits AR expression and activation and represses PCa cell and xenograft growth and castration resistance. Accordingly, GATA2 overexpression or COP1 mutations that disrupt COP1-GATA2 binding block COP1 tumor-suppressing activities. We conclude that GATA2 is a major COP1 substrate in PCa and that COP1 promotion of GATA2 degradation is a direct mechanism for regulating AR expression and activation, PCa growth, and castration resistance.
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Hao R, Hu J, Liu Y, Liang D, Li YM, Wang R, Zhang S, Wang P, Li YJ, Xie S. RFWD2 Knockdown as a Blocker to Reverse the Oncogenic Role of TRIB2 in Lung Adenocarcinoma. Front Oncol 2021; 11:733175. [PMID: 34646775 PMCID: PMC8503262 DOI: 10.3389/fonc.2021.733175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
RFWD2, an E3 ubiquitin ligase, is overexpressed in numerous human cancers, including leukemia, lung cancer, breast cancer, renal cell carcinoma, and colorectal cancer. The roles of RFWD2 in cancer are related to the targeting of its substrates for ubiquitination and degradation. This study aimed to investigate the role of TRIB2 in relation to the regulation of protein degradation through RFWD2. inBio Discover™ results demonstrated that TRIB2 can perform its functions by interacting with RFWD2 or other factors. TRIB2 can interact with and regulate RFWD2, which further attends the proteasome-mediated degradation of the RFWD2 substrate p-IκB-α. TRIB2 colocalizes with RFWD2-related IκB-α to form a ternary complex and further affects the IκB-α degradation by regulating its phosphorylation. Specific domain analysis showed that TRIB2 may bind to RFWD2 via its C-terminus, whereas it binds to IκB via its pseudokinase domain. TRIB2 acts as an oncogene and promotes cancer cell proliferation and migration, whereas RFWD2 knockdown reversed the role of TRIB2 in promoting cancer cell growth and colony formation in vitro and in vivo. In summary, this study reveals that TRIB2 promotes the progression of cancer by affecting the proteasome-mediated degradation of proteins through the interaction with RFWD2.
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Affiliation(s)
- Ruimin Hao
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
| | - Jinxia Hu
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
| | - Yuemei Liu
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
| | - Dongmin Liang
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
| | - Yan-Mei Li
- Department of Immune Rheumatism, Yantaishan Hospital, Yantai, China
| | - Ranran Wang
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
| | - Shucui Zhang
- Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan, China
| | - Pingyu Wang
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
| | - You-Jie Li
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
| | - Shuyang Xie
- Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, China
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6
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Liu W, Zhan Z, Zhang M, Sun B, Shi Q, Luo F, Zhang M, Zhang W, Hou Y, Xiao X, Li Y, Feng H. KAT6A, a novel regulator of β-catenin, promotes tumorigenicity and chemoresistance in ovarian cancer by acetylating COP1. Theranostics 2021; 11:6278-6292. [PMID: 33995658 PMCID: PMC8120227 DOI: 10.7150/thno.57455] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/29/2021] [Indexed: 12/20/2022] Open
Abstract
Background: Ovarian cancer is a fatal gynecologic malignancy that is found worldwide and exhibits an insidious onset and a lack of early warning symptoms. Despite ongoing studies, the mechanistic basis of the aggressive phenotypes of ovarian cancer remains unclear. Lysine acetyltransferase 6A (KAT6A) is a MYST-type histone acetyltransferase (HAT) enzyme identified as an oncogene in breast cancer, glioblastoma and leukemia. However, the specific functions of KAT6A in ovarian cancer remain unclear. Methods: Immunohistochemistry (IHC) staining and western blotting were performed to characterize KAT6A protein expression in ovarian cancer tissues and cell lines. The biological functions of KAT6A in ovarian cancer were evaluated by cell proliferation, wound healing and transwell invasion assays in vitro. Tumorigenesis and metastasis assays were performed in nude mice to detect the role of KAT6A in vivo. Mass spectrometry and immunoprecipitation assays were performed to detect the KAT6A-COP1 interaction. An in vivo ubiquitination assay was performed to determine the regulation of β-catenin by KAT6A. Results: In the present study, we revealed that KAT6A expression is upregulated in ovarian cancer and is associated with patient overall survival. Downregulation of KAT6A markedly inhibited the proliferation and migration abilities of ovarian cancer cells in vivo and in vitro. Additionally, the inhibition of KAT6A induced apoptosis and enhanced the sensitivity of ovarian cancer cells to cisplatin. Furthermore, KAT6A bound to and acetylated COP1 at K294. The acetylation of COP1 impaired COP1 function as an E3 ubiquitin ligase and led to the accumulation and enhanced activity of β-catenin. Conclusions: Our findings suggest that the KAT6A/COP1/β-catenin signaling axis plays a critical role in ovarian cancer progression and that targeting the KAT6A/COP1/β-catenin signaling axis could be a novel strategy for treating ovarian cancer.
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Affiliation(s)
- Wenxue Liu
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Zhiyan Zhan
- Key Laboratory of Pediatric Hematology and Oncology Ministry of Health, Department of Hematology & Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
- Department of Clinical Nutrition, Shanghai Children's Medical Center, School of Medicine Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Meiying Zhang
- Department of Obstetrics and Gynecology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Bowen Sun
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Qiqi Shi
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Fei Luo
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Mingda Zhang
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Weiwei Zhang
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yanli Hou
- Department of Radiotherapy, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Xiuying Xiao
- Department of Oncology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yanxin Li
- Key Laboratory of Pediatric Hematology and Oncology Ministry of Health, Department of Hematology & Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Haizhong Feng
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
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7
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Sun YB, Zhang XJ, Zhong MC, Dong X, Yu DM, Jiang XD, Wang D, Cui WH, Chen JH, Hu JY. Genome-wide identification of WD40 genes reveals a functional diversification of COP1-like genes in Rosaceae. PLANT MOLECULAR BIOLOGY 2020; 104:81-95. [PMID: 32621166 DOI: 10.1007/s11103-020-01026-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
Genome-wide identification of WD40-like genes reveals a duplication of COP1-like genes, one of the key players involved in regulation of flowering time and photomorphogenesis, with strong functional diversification in Rosaceae. WD40 proteins play crucial roles in a broad spectrum of developmental and physiological processes. Here, we conducted a systematic characterization of this family of genes in Rosa chinensis 'Old Blush' (OB), a founder genotype for modern rose domestication. We identified 187 rose WD40 genes and classified them into 5 clusters and 15 subfamilies with 11 of RcWD40s presumably generated via tandem duplication. We found RcWD40 genes were expressed differentially following stages of vegetative and reproductive development. We detected a duplication of CONSTITUTIVE PHOTOMORPHOGENIC1-like genes in rose (RcCOP1 and RcCOP1L) and other Rosaceae plants. Featuring a distinct expression pattern and a different profile of cis-regulatory-elements in the transcriptional regulatory regions, RcCOP1 seemed being evolutionarily conserved while RcCOP1L did not dimerize with RcHY5 and RcSPA4. Our data thus reveals a functional diversification of COP1-like genes in Rosacaeae plants, and provides a valuable resource to explore the potential function and evolution of WD40-like genes in Rosaceae plants.
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Affiliation(s)
- Yi-Bo Sun
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao-Jia Zhang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, 650223, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mi-Cai Zhong
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xue Dong
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Dong-Mei Yu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Xiao-Dong Jiang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dan Wang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei-Hua Cui
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiang-Hua Chen
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, 650223, Yunnan, China
| | - Jin-Yong Hu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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Han X, Huang X, Deng XW. The Photomorphogenic Central Repressor COP1: Conservation and Functional Diversification during Evolution. PLANT COMMUNICATIONS 2020; 1:100044. [PMID: 33367240 PMCID: PMC7748024 DOI: 10.1016/j.xplc.2020.100044] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/19/2020] [Accepted: 04/07/2020] [Indexed: 05/23/2023]
Abstract
Green plants on the earth have evolved intricate mechanisms to acclimatize to and utilize sunlight. In Arabidopsis, light signals are perceived by photoreceptors and transmitted through divergent but overlapping signaling networks to modulate plant photomorphogenic development. COP1 (CONSTITUTIVE PHOTOMORPHOGENIC 1) was first cloned as a central repressor of photomorphogenesis in higher plants and has been extensively studied for over 30 years. It acts as a RING E3 ubiquitin ligase downstream of multiple photoreceptors to target key light-signaling regulators for degradation, primarily as part of large protein complexes. The mammalian counterpart of COP1 is a pluripotent regulator of tumorigenesis and metabolism. A great deal of information on COP1 has been derived from whole-genome sequencing and functional studies in lower green plants, which enables us to illustrate its evolutionary history. Here, we review the current understanding about COP1, with a focus on the conservation and functional diversification of COP1 and its signaling partners in different taxonomic clades.
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Affiliation(s)
- Xue Han
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
- Peking University-Southern University of Science and Technology Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xi Huang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Xing Wang Deng
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
- Peking University-Southern University of Science and Technology Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
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Erk1/2 inactivation promotes a rapid redistribution of COP1 and degradation of COP1 substrates. Proc Natl Acad Sci U S A 2020; 117:4078-4087. [PMID: 32041890 DOI: 10.1073/pnas.1913698117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Anthrax lethal toxin (LT) is a protease virulence factor produced by Bacillus anthracis that is required for its pathogenicity. LT treatment causes a rapid degradation of c-Jun protein that follows inactivation of the MEK1/2-Erk1/2 signaling pathway. Here we identify COP1 as the ubiquitin E3 ligase that is essential for LT-induced c-Jun degradation. COP1 knockdown using siRNA prevents degradation of c-Jun, ETV4, and ETV5 in cells treated with either LT or the MEK1/2 inhibitor, U0126. Immunofluorescence staining reveals that COP1 preferentially localizes to the nuclear envelope, but it is released from the nuclear envelope into the nucleoplasm following Erk1/2 inactivation. At baseline, COP1 attaches to the nuclear envelope via interaction with translocated promoter region (TPR), a component of the nuclear pore complex. Disruption of this COP1-TPR interaction, through Erk1/2 inactivation or TPR knockdown, leads to rapid COP1 release from the nuclear envelope into the nucleoplasm where it degrades COP1 substrates. COP1-mediated degradation of c-Jun protein, combined with LT-mediated blockade of the JNK1/2 signaling pathway, inhibits cellular proliferation. This effect on proliferation is reversed by COP1 knockdown and ectopic expression of an LT-resistant MKK7-4 fusion protein. Taken together, this study reveals that the nuclear envelope acts as a reservoir, maintaining COP1 poised for action. Upon Erk1/2 inactivation, COP1 is rapidly released from the nuclear envelope, promoting the degradation of its nuclear substrates, including c-Jun, a critical transcription factor that promotes cellular proliferation. This regulation allows mammalian cells to respond rapidly to changes in extracellular cues and mediates pathogenic mechanisms in disease states.
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10
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Song Y, Liu Y, Pan S, Xie S, Wang ZW, Zhu X. Role of the COP1 protein in cancer development and therapy. Semin Cancer Biol 2020; 67:43-52. [PMID: 32027978 DOI: 10.1016/j.semcancer.2020.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 01/29/2020] [Accepted: 02/01/2020] [Indexed: 12/31/2022]
Abstract
COP1, an E3 ubiquitin ligase, has been demonstrated to play a vital role in the regulation of cell proliferation, apoptosis and DNA repair. Accumulated evidence has revealed that COP1 is involved in carcinogenesis via targeting its substrates, including p53, c-Jun, ETS, β-catenin, STAT3, MTA1, p27, 14-3-3σ, and C/EBPα, for ubiquitination and degradation. COP1 can play tumor suppressive and oncogenic roles in human malignancies, urging us to summarize the functions of COP1 in tumorigenesis. In this review, we describe the structure of COP1 and its known substrates. Moreover, we dissect the function of COP1 by physiological (mouse models), pathological (human tumor specimens) and biochemical (ubiquitin substrates) Evidence. Furthermore, we discuss COP1 as a potential therapeutic target for cancer therapy.
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Affiliation(s)
- Yizuo Song
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
| | - Yi Liu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
| | - Shuya Pan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
| | - Shangdan Xie
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China
| | - Zhi-Wei Wang
- Center of Scientific Research, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027, Zhejiang, 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, 325027, Zhejiang, China.
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11
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Kung JE, Jura N. The pseudokinase TRIB1 toggles an intramolecular switch to regulate COP1 nuclear export. EMBO J 2019; 38:e99708. [PMID: 30692133 PMCID: PMC6376274 DOI: 10.15252/embj.201899708] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 12/18/2018] [Accepted: 12/20/2018] [Indexed: 01/17/2023] Open
Abstract
COP1 is a highly conserved ubiquitin ligase that regulates diverse cellular processes in plants and metazoans. Tribbles pseudokinases, which only exist in metazoans, act as scaffolds that interact with COP1 and its substrates to facilitate ubiquitination. Here, we report that, in addition to this scaffolding role, TRIB1 promotes nuclear localization of COP1 by disrupting an intramolecular interaction between the WD40 domain and a previously uncharacterized regulatory site within COP1. This site, which we have termed the pseudosubstrate latch (PSL), resembles the consensus COP1-binding motif present in known COP1 substrates. Our findings support a model in which binding of the PSL to the WD40 domain stabilizes a conformation of COP1 that is conducive to CRM1-mediated nuclear export, and TRIB1 displaces this intramolecular interaction to induce nuclear retention of COP1. Coevolution of Tribbles and the PSL in metazoans further underscores the importance of this role of Tribbles in regulating COP1 function.
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Affiliation(s)
- Jennifer E Kung
- Cardiovascular Research Institute, University of California-San Francisco, San Francisco, CA, USA
| | - Natalia Jura
- Cardiovascular Research Institute, University of California-San Francisco, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California-San Francisco, San Francisco, CA, USA
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12
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Kim JY, Song JT, Seo HS. COP1 regulates plant growth and development in response to light at the post-translational level. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4737-4748. [PMID: 28992300 DOI: 10.1093/jxb/erx312] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Photoreceptors perceive different wavelengths of light and transduce light signals downstream via a range of proteins. COP1, an E3 ubiquitin ligase, regulates light signaling by mediating the ubiquitination and subsequent proteasomal degradation of photoreceptors such as phytochromes and cryptochromes, as well as various development-related proteins including other light-responsive proteins. COP1 is itself regulated by direct interactions with several signaling molecules that modulate its activity. The control of photomorphogenesis by COP1 is also regulated by its localization to the cytoplasm in response to light. COP1 thus acts as a tightly regulated switch that determines whether development is skotomorphogenic or photomorphogenic. In this review, we discuss the effects of COP1 on the abundance and activity of various development-related proteins, including photoreceptors, and summarize the regulatory mechanisms that influence COP1 activity and stability in plants.
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Affiliation(s)
- Joo Yong Kim
- Department of Plant Science and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
| | - Jong Tae Song
- School of Applied Biosciences, Kyungpook National University, Daegu 702-701, Korea
| | - Hak Soo Seo
- Department of Plant Science and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea
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13
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HuCOP1 contributes to the regulation of DNA repair in keratinocytes. Mol Cell Biochem 2016; 427:103-109. [PMID: 27995412 DOI: 10.1007/s11010-016-2901-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/02/2016] [Indexed: 10/20/2022]
Abstract
We have previously demonstrated that the E3 ligase Human Constitutive Photomorphogenic Protein (huCOP1) is expressed in human keratinocytes and negatively regulates p53. The MutS homolog 2 (MSH2) protein plays a central role in DNA MMR mechanism and is implicated in the cellular response to anticancer agents, such as cisplatin. Our aim was to clarify whether huCOP1 plays a role in DNA MMR by affecting MSH2 protein level in human keratinocytes. To define the role of huCOP1 in DNA mismatch repair, we determined whether huCOP1 affects MSH2 abundance. MSH2 protein level was detected by immunocytochemical staining using a keratinocyte cell line in which the expression level of huCOP1 was stably decreased (siCOP1). To investigate whether huCOP1 silencing influences cisplatin-induced cell death, control and siCOP1 keratinocyte cells were treated with increasing concentrations of cisplatin and cell viability was recorded after 48 and 96 h. Stable silencing of huCOP1 in human keratinocytes resulted in a reduced level of MSH2 protein. huCOP1 silencing also sensitized keratinocytes to the interstrand crosslinking inducer cisplatin. Our results indicate that decreased huCOP1 correlates with lower MSH2 levels. These protein level changes lead to increased sensitivity toward cisplatin treatment, implicating that huCOP1 plays a positive role in maintaining genome integrity in human keratinocytes.
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Lamm CE, Scherer M, Reuter N, Amin B, Stamminger T, Sonnewald U. Human promyelocytic leukemia protein is targeted to distinct subnuclear domains in plant nuclei and colocalizes with nucleolar constituents in a SUMO-dependent manner. FEBS Open Bio 2016; 6:1141-1154. [PMID: 27833854 PMCID: PMC5095151 DOI: 10.1002/2211-5463.12134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/23/2016] [Accepted: 09/28/2016] [Indexed: 01/15/2023] Open
Abstract
Eukaryotic nuclei are subdivided into subnuclear structures. Among the most prominent of these structures are the nucleolus and the PML nuclear bodies (PML‐NBs). PML‐NBs are spherical multiprotein aggregates of varying size localized in the interchromosomal area. PML‐NB formation is dependent on the presence of the promyelocytic leukemia protein (PML) as well as on post‐translational modification of core components by covalent attachment of the small ubiquitin‐like modifier (SUMO). So far, PML‐NBs as well as PML have been described in mammalian cells only, whereas no orthologs are known in the plant kingdom. In order to investigate conserved mechanisms in PML targeting, we expressed human PML (hPML) fused to the GFP in Nicotiana benthamiana. Using confocal laser scanning microscopy and coimmunoprecipitation followed by mass spectrometric analysis, we found the fusion protein in association with nucleolar constituents. Importantly, mutants of hPML, which are no longer SUMOylated, showed altered localizations, implying SUMO‐dependent targeting of hPML in plants as has previously been shown for mammalian cells. Interestingly, in the presence of proteasome inhibitors, hPML could also be found in the nucleolus of mammalian cells suggesting conserved targeting mechanisms of PML across kingdoms. Finally, Solanum tuberosum COP1, a proposed PML‐like protein from plants, was fused to the red fluorescent protein (RFP) and coexpressed with hPML::eGFP. Microscopic analysis confirmed the localization of COP1::RFP in nuclear speckles. However, hPML::eGFP did not colocalize with COP1::RFP. Hence, we conclude that plants do not possess specialized PML‐NBs, but that their functions may be covered by other subnuclear structures like the nucleolus. Database Proteomics data have been deposited to the ProteomeXchange Consortium with the identifier PXD004254.
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Affiliation(s)
- Christian E Lamm
- Division of Biochemistry Department of Biology Friedrich-Alexander University Erlangen-Nuremberg Germany
| | - Myriam Scherer
- Institute for Clinical and Molecular Virology Friedrich-Alexander University Erlangen-Nuremberg Germany
| | - Nina Reuter
- Institute for Clinical and Molecular Virology Friedrich-Alexander University Erlangen-Nuremberg Germany
| | - Bushra Amin
- Division of Biochemistry Department of Biology Friedrich-Alexander University Erlangen-Nuremberg Germany; Present address: Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology Friedrich-Alexander University Erlangen-Nuremberg Germany
| | - Uwe Sonnewald
- Division of Biochemistry Department of Biology Friedrich-Alexander University Erlangen-Nuremberg Germany
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15
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Sanchez-Barcelo EJ, Mediavilla MD, Vriend J, Reiter RJ. Constitutive photomorphogenesis protein 1 (COP1) and COP9 signalosome, evolutionarily conserved photomorphogenic proteins as possible targets of melatonin. J Pineal Res 2016; 61:41-51. [PMID: 27121162 DOI: 10.1111/jpi.12340] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 04/26/2016] [Indexed: 12/18/2022]
Abstract
The ubiquitin proteasome system has been proposed as a possible mechanism involved in the multiple actions of melatonin. COP1 (constitutive photomorphogenesis protein 1), a RING finger-type ubiquitin E3 ligase formerly identified in Arabidopsis, is a central switch for the transition from plant growth underground in darkness (etiolation) to growth under light exposure (photomorphogenesis). In darkness, COP1 binds to photomorphogenic transcription factors driving its degradation via the 26S proteasome; blue light, detected by cryptochromes, and red and far-red light detected by phytochromes, negatively regulate COP1. Homologues of plant COP1 containing all the structural features present in Arabidopsis as well as E3 ubiquitin ligase activity have been identified in mice and humans. Substrates for mammalian (m) COP1 include p53, AP-1 and c-Jun, p27(Kip1) , ETV1, MVP, 14-3-3σ, C/EBPα, MTA1, PEA3, ACC, TORC2 and FOXO1. This mCOP1 target suggests functions related to tumorigenesis, gluconeogenesis, and lipid metabolism. The role of mCOP1 in tumorigenesis (either as a tumor promoter or tumor suppressor), as well as in glucose metabolism (inhibition of gluconeogenesis) and lipid metabolism (inhibition of fatty acid synthesis), has been previously demonstrated. COP1, along with numerous other ubiquitin ligases, is regulated by the COP9 signalosome; this protein complex is associated with the oxidative stress sensor Keap1 and the deubiquitinase USP15. The objective of this review was to provide new information on the possible role of COP1 and COP9 as melatonin targets. The hypothesis is based on common functional aspects of melatonin and COP1 and COP9, including their dependence on light, regulation of the metabolism, and their control of tumor growth.
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Affiliation(s)
| | - Maria D Mediavilla
- Department of Physiology and Pharmacology, University of Cantabria, Santander, Spain
| | - Jerry Vriend
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada
| | - Russel J Reiter
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
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16
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FU CHUNLING, GONG YANQING, SHI XUANXUAN, SHI HENGLIANG, WAN YAN, WU QINGYUN, XU KAILIN. Expression and regulation of COP1 in chronic lymphocytic leukemia cells for promotion of cell proliferation and tumorigenicity. Oncol Rep 2015; 35:1493-500. [DOI: 10.3892/or.2015.4526] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 11/18/2015] [Indexed: 11/06/2022] Open
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17
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Abstract
COP1 is an E3 ubiquitin ligase that is involved in the ubiquitylation of various protein substrates to trigger their proteasomal degradation. Although originally identified in a light signalling pathway in plants, biochemical studies have identified putative targets of mammalian COP1 with relevant roles in tumorigenesis, including the oncoproteins JUN and ETV family members, as well as the p53 tumour suppressor. Recent genetic studies have shown that COP1 deficiency leads to spontaneous tumour formation in mice, and have identified mutations in COP1 and its substrates in various human cancers. These findings add to our growing appreciation of the roles for E3 ligases in cancer.
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Affiliation(s)
- Jean-Christophe Marine
- Laboratory for Molecular Cancer Biology, VIB-KULeuven, O&N I Herestraat 49, Leuven, Belgium.
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18
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Lee SW, Seong MW, Jeon YJ, Chung CH. Ubiquitin E3 ligases controlling p53 stability. Anim Cells Syst (Seoul) 2012. [DOI: 10.1080/19768354.2012.688769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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19
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Li DQ, Ohshiro K, Reddy SDN, Pakala SB, Lee MH, Zhang Y, Rayala SK, Kumar R. E3 ubiquitin ligase COP1 regulates the stability and functions of MTA1. Proc Natl Acad Sci U S A 2009; 106:17493-8. [PMID: 19805145 PMCID: PMC2762678 DOI: 10.1073/pnas.0908027106] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Indexed: 11/18/2022] Open
Abstract
Metastasis-associated protein 1 (MTA1), a component of the nucleosome remodeling and histone deacetylation (NuRD) complex, is widely upregulated in human cancers. However, the mechanism for regulating its protein stability remains unknown. Here we report that MTA1 is an ubiquitinated protein and targeted by the RING-finger E3 ubiquitin-protein ligase constitutive photomorphogenesis protein 1 (COP1) for degradation via the ubiquitin-proteasome pathway. Induced expression of wild-type COP1 but not its RING motif mutants promotes the ubiquitination and degradation of MTA1, indicating that the ligase activity is required for the COP1-mediated proteolysis of MTA1. Conversely, depletion of endogenous COP1 resulted in a marked decrease in MTA1 ubiquitination, accompanied by a pronounced accumulation of MTA1 protein. MTA1, in turn, destabilizes COP1 by promoting its autoubiquitination, thus creating a tight feedback loop that regulates both MTA1 and COP1 protein stability. Accordingly, disruption of the COP1-mediated proteolysis by ionizing radiation leads to MTA1 stabilization, accompanied by an increased coregulatory function of MTA1 on its target. Furthermore, we discovered that MTA1 is required for optimum DNA double-strand break repair after ionizing radiation. These findings provide novel insights into the regulation of MTA1 protein and reveal a novel function of MTA1 in DNA damage response.
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Affiliation(s)
- Da-Qiang Li
- Department of Biochemistry and Molecular Biology and Institute of Coregulator Biology, The George Washington University Medical Center, Washington, DC 20037
| | - Kazufumi Ohshiro
- Department of Biochemistry and Molecular Biology and Institute of Coregulator Biology, The George Washington University Medical Center, Washington, DC 20037
| | - Sirigiri Divijendra Natha Reddy
- Department of Biochemistry and Molecular Biology and Institute of Coregulator Biology, The George Washington University Medical Center, Washington, DC 20037
| | - Suresh B. Pakala
- Department of Biochemistry and Molecular Biology and Institute of Coregulator Biology, The George Washington University Medical Center, Washington, DC 20037
| | - Mong-Hong Lee
- Department of Molecular & Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030; and
| | - Yanping Zhang
- Radiation Oncology and Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Suresh K. Rayala
- Department of Biochemistry and Molecular Biology and Institute of Coregulator Biology, The George Washington University Medical Center, Washington, DC 20037
| | - Rakesh Kumar
- Department of Biochemistry and Molecular Biology and Institute of Coregulator Biology, The George Washington University Medical Center, Washington, DC 20037
- Department of Molecular & Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030; and
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20
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Kinyó A, Kiss-László Z, Hambalkó S, Bebes A, Kiss M, Széll M, Bata-Csörgo Z, Nagy F, Kemény L. COP1 contributes to UVB-induced signaling in human keratinocytes. J Invest Dermatol 2009; 130:541-5. [PMID: 19741714 DOI: 10.1038/jid.2009.286] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
UVB irradiation has been shown to trigger a broad range of changes in gene expression in human skin; however, factors governing these events are still not well understood. In this study, we show that human constitutive photomorphogenic protein-1 (huCOP1), an E3 ligase, contributes to the orchestration of UVB response of keratinocytes. Accordingly, our data show that (i) huCOP1 protein is expressed both in the nucleus and in the cytoplasm of cultured keratinocytes, (ii) UVB reduces the levels of the huCOP1 mRNA and protein, and (iii) induces changes in the subcellular localization of huCOP1. Finally, we show that gene-specific silencing of huCOP1 induces the accumulation of the tumor suppressor p53 protein, which is further increased after UVB irradiation.
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Affiliation(s)
- Agnes Kinyó
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary.
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21
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Kato S, Ding J, Pisck E, Jhala US, Du K. COP1 functions as a FoxO1 ubiquitin E3 ligase to regulate FoxO1-mediated gene expression. J Biol Chem 2008; 283:35464-73. [PMID: 18815134 PMCID: PMC2602905 DOI: 10.1074/jbc.m801011200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 09/22/2008] [Indexed: 02/06/2023] Open
Abstract
COP1 is a Ring-Finger E3 ubiquitin ligase that is involved in plant development, mammalian cell survival, growth, and metabolism. Here we report that COP1, whose expression is enhanced by insulin, regulates FoxO1 protein stability. We found that in Fao hepatoma cells, ectopic expression of COP1 decreased, whereas knockdown of COP1 expression increased the level of endogenous FoxO1 protein without impacting other factors such as C/EBPalpha and CREB (cAMP-response element-binding protein). We further showed that COP1 binds FoxO1, enhances its ubiquitination, and promotes its degradation via the ubiquitin-proteasome pathway. To determine the biological significance of COP1-mediated FoxO1 protein degradation, we have examined the impact of COP1 on FoxO1-mediated gene expression and found that COP1 suppressed FoxO1 reporter gene as well as FoxO1 target genes such as glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, two key targets for FoxO1 in the regulation of gluconeogenesis, with corresponding changes of hepatic glucose production in Fao cells. We suggest that by functioning as a FoxO1 E3 ligase, COP1 may play a role in the regulation of hepatic glucose metabolism.
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Affiliation(s)
- Satomi Kato
- Molecular Oncology Research Institute, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA
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22
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Yi C, Li S, Wang J, Wei N, Deng XW. Affinity purification reveals the association of WD40 protein constitutive photomorphogenic 1 with the hetero-oligomeric TCP-1 chaperonin complex in mammalian cells. Int J Biochem Cell Biol 2006; 38:1076-83. [PMID: 16497536 DOI: 10.1016/j.biocel.2005.12.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2005] [Revised: 10/25/2005] [Accepted: 12/21/2005] [Indexed: 11/29/2022]
Abstract
Constitutive photomorphogenic 1 (COP1), a protein composed of a RING finger, a coiled-coil domain and seven WD40 repeats, functions as an E3 ubiquitin ligase that targets key transcription factors for ubiquitination and degradation in both higher plants and mammalian cells. While COP1 is required for light-mediated development in plants, its mammalian counterpart has been implicated in tumorigenesis. We previously showed that COP1 forms high-molecular-weight complexes in mammalian cells. Here we report our attempts in characterizing the components of the mammalian COP1 complexes by affinity purification combined with mass spectral analysis. We find that both transiently and stably expressed COP1 associates with the hetero-oligomeric TCP-1 chaperonin complex (TRiC), heat shock protein 70 (Hsp70) and BAG-family molecular chaperone regulator-2 (BAG2). In addition, stably expressed COP1 binds to major vault protein (MVP) and translocated promoter region (Tpr). The TRiC/Hsp70 complex is known to interact with and assist in the folding of a number of WD40 proteins in Saccharomyces cerevisiae. The association of WD40 protein COP1 with TRiC/Hsp70 in mammalian cells suggests that facilitating the folding of WD40 proteins may be a conserved function for TRiC/Hsp70 from yeast to mammals.
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Affiliation(s)
- Chunling Yi
- Department of Molecular, Cellular and Developmental Biology, Yale University, P.O. Box 208104, 165 Prospect Street, OML 352A, New Haven, CT 06520-8104, USA
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23
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Yi C, Deng XW. COP1 - from plant photomorphogenesis to mammalian tumorigenesis. Trends Cell Biol 2005; 15:618-25. [PMID: 16198569 DOI: 10.1016/j.tcb.2005.09.007] [Citation(s) in RCA: 235] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Revised: 08/24/2005] [Accepted: 09/20/2005] [Indexed: 10/25/2022]
Abstract
The COP1 (constitutive photomorphogenic 1) protein, comprising RING finger, coiled-coil and WD40 domains, is conserved in both higher plants and vertebrates. In plants, COP1 acts as an E3 ubiquitin ligase to repress light signaling by targeting photoreceptors and downstream transcription factors for ubiquitylation and degradation. The activity of COP1 in plant cells correlates with its cytoplasmic and nuclear partitioning according to dark or light conditions. In addition, various signaling molecules have been shown to directly interact with COP1 and modulate its activity. Recently, scientists have begun to probe the function and regulation of COP1 in mammalian systems. Initial studies have pointed at possible roles for mammalian COP1 in tumorigenesis and the stress response through regulating the activities of p53 and c-Jun.
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Affiliation(s)
- Chunling Yi
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA
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24
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Yi C, Li S, Chen X, Wiemer EAC, Wang J, Wei N, Deng XW. Major Vault Protein, in Concert with Constitutively Photomorphogenic 1, Negatively Regulates c-Jun–Mediated Activator Protein 1 Transcription in Mammalian Cells. Cancer Res 2005; 65:5835-40. [PMID: 15994960 DOI: 10.1158/0008-5472.can-05-0423] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Constitutively photomorphogenic 1 (COP1), a RING finger ubiquitin ligase with substrates including c-Jun and p53, was recently found to be overexpressed in a number of breast and ovarian tumor samples. In addition to its E3 activity, COP1 was also shown to be able to inhibit activator protein 1 (AP-1) transcription. Through an affinity purification method, we have identified major vault protein (MVP) as a novel interacting partner for COP1 in mammalian cells. MVP, also known as lung resistance protein, is the main component of a ribonucleoprotein organelle called vault, and has been implicated in multiple drug resistance in many cancer cell lines and primary tumor samples. The interaction between COP1 and MVP is detectable at the endogenous level and occurs mostly in the cytoplasm. Similar to COP1, MVP inhibits c-Jun accumulation and AP-1 transcription activity. MVP knockout or knockdown cells contain elevated amount of c-Jun and increased AP-1 transcription activity. UV irradiation enhances MVP tyrosine phosphorylation, causes dissociation of COP1 from MVP, and alleviates the inhibitory activity of MVP on AP-1 transcription. Taken together, we propose that MVP, most likely through its interaction with COP1, suppresses c-Jun-mediated AP-1 transcription under unstressed conditions, thereby preventing cells from undergoing stress response.
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Affiliation(s)
- Chunling Yi
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA
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25
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Dornan D, Wertz I, Shimizu H, Arnott D, Frantz GD, Dowd P, O'Rourke K, Koeppen H, Dixit VM. The ubiquitin ligase COP1 is a critical negative regulator of p53. Nature 2004; 429:86-92. [PMID: 15103385 DOI: 10.1038/nature02514] [Citation(s) in RCA: 525] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Accepted: 03/29/2004] [Indexed: 11/08/2022]
Abstract
COP1 (constitutively photomorphogenic 1) is a RING-finger-containing protein that functions to repress plant photomorphogenesis, the light-mediated programme of plant development. Mutants of COP1 are constitutively photomorphogenic, and this has been attributed to their inability to negatively regulate the proteins LAF1 (ref. 1) and HY5 (ref. 2). The role of COP1 in mammalian cells is less well characterized. Here we identify the tumour-suppressor protein p53 as a COP1-interacting protein. COP1 increases p53 turnover by targeting it for degradation by the proteasome in a ubiquitin-dependent fashion, independently of MDM2 or Pirh2, which are known to interact with and negatively regulate p53. Moreover, COP1 serves as an E3 ubiquitin ligase for p53 in vitro and in vivo, and inhibits p53-dependent transcription and apoptosis. Depletion of COP1 by short interfering RNA (siRNA) stabilizes p53 and arrests cells in the G1 phase of the cell cycle. Furthermore, we identify COP1 as a p53-inducible gene, and show that the depletion of COP1 and MDM2 by siRNA cooperatively sensitizes U2-OS cells to ionizing-radiation-induced cell death. Overall, these results indicate that COP1 is a critical negative regulator of p53 and represents a new pathway for maintaining p53 at low levels in unstressed cells.
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Affiliation(s)
- David Dornan
- Department of Molecular Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, USA
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26
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Subramanian C, Kim BH, Lyssenko NN, Xu X, Johnson CH, von Arnim AG. The Arabidopsis repressor of light signaling, COP1, is regulated by nuclear exclusion: mutational analysis by bioluminescence resonance energy transfer. Proc Natl Acad Sci U S A 2004; 101:6798-802. [PMID: 15084749 PMCID: PMC404125 DOI: 10.1073/pnas.0307964101] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bioluminescence resonance energy transfer (BRET) between Renilla luciferase and yellow fluorescent protein has been adapted to serve as a real-time reporter on protein-protein interactions in live plant cells by using the Arabidopsis Constitutive photomorphogenesis 1 (COP1) protein as a model system. COP1 is a repressor of light signal transduction that functions as part of a nuclear E3 ubiquitin ligase. COP1 possesses a leucine-rich nuclear-exclusion signal that resides in a domain implicated in COP1 dimerization. BRET was applied in conjunction with site-directed mutagenesis to explore the respective contributions of the nuclear-exclusion and dimerization motifs to the regulation of COP1 activity in vivo. One specific mutant protein, COP1(L105A), showed increased nuclear accumulation but retained the ability to dimerize, as monitored by BRET, whereas other mutations inhibited both nuclear exclusion and COP1 dimerization. Mutant rescue and overexpression experiments indicated that nuclear exclusion of COP1 protein is a rate-limiting step in light signal transduction.
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Affiliation(s)
- Chitra Subramanian
- Department of Botany, University of Tennessee, Knoxville, TN 37996-1100, USA
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27
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Wertz IE, O'Rourke KM, Zhang Z, Dornan D, Arnott D, Deshaies RJ, Dixit VM. Human De-etiolated-1 regulates c-Jun by assembling a CUL4A ubiquitin ligase. Science 2004; 303:1371-4. [PMID: 14739464 DOI: 10.1126/science.1093549] [Citation(s) in RCA: 287] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Arabidopsis thaliana De-etiolated-1 (AtDET1) is a highly conserved protein, with orthologs in vertebrate and invertebrate organisms. AtDET1 negatively regulates photomorphogenesis, but its biochemical mechanism and function in other species are unknown. We report that human DET1 (hDET1) promotes ubiquitination and degradation of the proto-oncogenic transcription factor c-Jun by assembling a multisubunit ubiquitin ligase containing DNA Damage Binding Protein-1 (DDB1), cullin 4A (CUL4A), Regulator of Cullins-1 (ROC1), and constitutively photomorphogenic-1. Ablation of any subunit by RNA interference stabilized c-Jun and increased c-Jun-activated transcription. These findings characterize a c-Jun ubiquitin ligase and define a specific function for hDET1 in mammalian cells.
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Affiliation(s)
- Ingrid E Wertz
- Department of Molecular Oncology, Genentech, Inc., South San Francisco, CA 94080, USA
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