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Jiang Y, Liu X, Shen R, Gu X, Qian W. Fbxo21 regulates the epithelial-to-mesenchymal transition through ubiquitination of Nr2f2 in gastric cancer. J Cancer 2021; 12:1421-1430. [PMID: 33531987 PMCID: PMC7847638 DOI: 10.7150/jca.49674] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 12/10/2020] [Indexed: 12/11/2022] Open
Abstract
F-box protein 21 (Fbxo21), a member of the F-box family proteins, constitutes one of the four subunits of an E3 ubiquitin ligase complex called SCFs (SKP1-Cullin-F-box). Despite the effect on antivirus immune response and ubiquitination regulation of a few oncoproteins, such as EID1 and P-gp, little is known about the Fbxo21 function in tumors, including gastric cancer. In our study, we confirmed that Fbxo21 expression was decreased in gastric cancer tissues. Decreased expression of Fbxo21 was significantly associated with poor prognosis in gastric cancer. Fbxo21 inhibited gastric cancer progression by inducing growth arrest and inhibiting migration and invasion. The expression of various EMT markers, such as E-cadherin, N-cadherin and Vimentin were altered after Fbxo21 knockdown or overexpression. Moreover, we demonstrated that Fbxo21 inhibited the EMT via the down-regulation of Nr2f2. Fbxo21 expression was negatively correlated with Nr2f2 protein expression in gastric cancer tissues and cell lines. And the Nr2f2 protein abundance was regulated by Fbxo21 via ubiquitination and proteasomal degradation. At last, we demonstrated the effects of Nr2f2 re-expression and inhibition on stable Fbxo21-overexpression or Fbxo21-silenced cell lines. These results suggested that Fbxo21 inhibited the proliferation and EMT in part through down-regulating the Nr2f2.
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Affiliation(s)
- Yannan Jiang
- Department of General Surgery, The Affiliated Suzhou Hospital of Nanjing Medical University
| | - Xinyu Liu
- Department of General Surgery, The First Affiliated Hospital of Zhengzhou University
| | - Renbin Shen
- Department of General Surgery, The Affiliated Suzhou Hospital of Nanjing Medical University
| | - Xinhua Gu
- Department of General Surgery, The Affiliated Suzhou Hospital of Nanjing Medical University
| | - Weifeng Qian
- Department of General Surgery, The Affiliated Suzhou Hospital of Nanjing Medical University
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Yu Z, Chen T, Li X, Yang M, Tang S, Zhu X, Gu Y, Su X, Xia M, Li W, Zhang X, Wang Q, Cao X, Wang J. Lys29-linkage of ASK1 by Skp1-Cullin 1- Fbxo21 ubiquitin ligase complex is required for antiviral innate response. eLife 2016; 5. [PMID: 27063938 PMCID: PMC4887211 DOI: 10.7554/elife.14087] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 04/09/2016] [Indexed: 12/25/2022] Open
Abstract
Protein ubiquitination regulated by ubiquitin ligases plays important roles in innate immunity. However, key regulators of ubiquitination during innate response and roles of new types of ubiquitination (apart from Lys48- and Lys63-linkage) in control of innate signaling have not been clearly understood. Here we report that F-box only protein Fbxo21, a functionally unknown component of SCF (Skp1–Cul1–F-box protein) complex, facilitates Lys29-linkage and activation of ASK1 (apoptosis signal-regulating kinase 1), and promotes type I interferon production upon viral infection. Fbxo21 deficiency in mice cells impairs virus-induced Lys29-linkage and activation of ASK1, attenuates c-Jun N-terminal kinase (JNK) and p38 signaling pathway, and decreases the production of proinflammatory cytokines and type I interferon, resulting in reduced antiviral innate response and enhanced virus replication. Therefore Fbxo21 is required for ASK1 activation via Lys29-linkage of ASK1 during antiviral innate response, providing mechanistic insights into non-proteolytic roles of SCF complex in innate immune response. DOI:http://dx.doi.org/10.7554/eLife.14087.001 The innate immune system is the body’s first line of defense against being infected by viruses and other microbes. Upon recognizing a virus, host cells trigger the innate immune response in an effort to eliminate the threat. However, innate immune responses must be carefully controlled because an excessive response can cause inflammation that harms the body. The innate immune response involves a variety of cells and processes that are each activated through a series of communication systems called signaling pathways. While much has been learned about which parts of a virus trigger the innate immune response, it is not clear how the immune response to the virus is controlled. It has been suggested that a process known as ubiquitination could be involved in regulating the activity of signaling pathways that activate the innate immune response. During ubiquitination, enzymes attach a small molecule called ubiquitin to a specific target protein. Ubiquitin often acts as a label that targets a particular protein for destruction. Enzymes called E3 ubiquitin ligases play central roles in identifying specific target proteins for ubiquitination. Some of these enzymes consist of a single protein unit that acts alone, but other E3 ubiquitin ligases are formed by groups (or “complexes”) of several proteins working together. Members of the F-box only protein family are components of some ubiquitin ligase complexes. Here, Yu et al. used a “microarray” technique to assess which F-box only proteins in mice are produced during an immune response to two viruses. The experiments identified an F-box protein called Fbxo21 as a potential candidate for a role in regulating the innate immune response. Additional experiments revealed that Fbxo21 is involved in adding ubiquitin to a specific location on a signaling protein called ASK1, which is known to be crucial for innate immune responses. Instead of targeting ASK1 for destruction, this ubiquitination activates ASK1. Therefore, Yu et al.’s findings demonstrate that Fbxo21 plays an important role in regulating innate immune responses. A future challenge is to investigate exactly how ASK1 is activated by the ubiquitin. DOI:http://dx.doi.org/10.7554/eLife.14087.002
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Affiliation(s)
- Zhou Yu
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China.,National Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Taoyong Chen
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China
| | - Xuelian Li
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China
| | - Mingjin Yang
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China.,National Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Songqing Tang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xuhui Zhu
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China
| | - Yan Gu
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China
| | - Xiaoping Su
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China
| | - Meng Xia
- National Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Weihua Li
- Institute of Basic Medical Sciences, National Center of Biomedical Analysis, Beijing, China
| | - Xuemin Zhang
- Institute of Basic Medical Sciences, National Center of Biomedical Analysis, Beijing, China
| | - Qingqing Wang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xuetao Cao
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, China.,National Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Jianli Wang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
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