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Li Z, Sun S, Wang Y, Hua Y, Liu M, Zhou Y, Zhong L, Li T, Zhao H, Zhou X, Zeng X, Chen Q, Li J. PA28γ coordinates the cross-talk between cancer-associated fibroblasts and tumor cells to promote OSCC progression via HDAC1/E2F3/IGF2 signaling. Cancer Lett 2024:216962. [PMID: 38768680 DOI: 10.1016/j.canlet.2024.216962] [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: 02/05/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/22/2024]
Abstract
PA28γ overexpression is aberrant and accompanied by poor patient prognosis in various cancers, the precise regulatory mechanism of this crucial gene in the tumor microenvironment remains incompletely understood. In this study, using oral squamous cell carcinoma as a model, we demonstrated that PA28γ exhibits high expression in cancer-associated fibroblasts (CAFs), and its expression significantly correlates with the severity of clinical indicators of malignancy. Remarkably, we found that elevated levels of secreted IGF2 from PA28γ+ CAFs can enhance stemness maintenance and promote tumor cell aggressiveness through the activation of the MAPK/AKT pathway in a paracrine manner. Mechanistically, PA28γ upregulates IGF2 expression by stabilizing the E2F3 protein, a transcription factor of IGF2. Further mechanistic insights reveal that HDAC1 predominantly mediates the deacetylation and subsequent ubiquitination and degradation of E2F3. Notably, PA28γ interacts with HDAC1 and accelerates its degradation via a 20S proteasome-dependent pathway. Additionally, PA28γ+ CAFs exert an impact on the tumor immune microenvironment by secreting IGF2. Excitingly, our study suggests that targeting PA28γ+ CAFs or secreted IGF2 could increase the efficacy of PD-L1 therapy. Thus, our findings reveal the pivotal role of PA28γ in cell interactions in the tumor microenvironment and propose novel strategies for augmenting the effectiveness of immune checkpoint blockade in oral squamous cell carcinoma.
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Affiliation(s)
- Zaiye Li
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Silu Sun
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Ying Wang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yufei Hua
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Ming Liu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yu Zhou
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Liang Zhong
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Taiwen Li
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Hang Zhao
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Xikun Zhou
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Xin Zeng
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Qianming Chen
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China.
| | - Jing Li
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Research Unit of Oral Carcinogenesis and Management & Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China.
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2
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Wang M, Lin H. Understanding the Function of Mammalian Sirtuins and Protein Lysine Acylation. Annu Rev Biochem 2021; 90:245-285. [PMID: 33848425 DOI: 10.1146/annurev-biochem-082520-125411] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein lysine acetylation is an important posttranslational modification that regulates numerous biological processes. Targeting lysine acetylation regulatory factors, such as acetyltransferases, deacetylases, and acetyl-lysine recognition domains, has been shown to have potential for treating human diseases, including cancer and neurological diseases. Over the past decade, many other acyl-lysine modifications, such as succinylation, crotonylation, and long-chain fatty acylation, have also been investigated and shown to have interesting biological functions. Here, we provide an overview of the functions of different acyl-lysine modifications in mammals. We focus on lysine acetylation as it is well characterized, and principles learned from acetylation are useful for understanding the functions of other lysine acylations. We pay special attention to the sirtuins, given that the study of sirtuins has provided a great deal of information about the functions of lysine acylation. We emphasize the regulation of sirtuins to illustrate that their regulation enables cells to respond to various signals and stresses.
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Affiliation(s)
- Miao Wang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA;
| | - Hening Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA; .,Howard Hughes Medical Institute, Cornell University, Ithaca, New York 14853, USA
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3
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Račková L, Csekes E. Proteasome Biology: Chemistry and Bioengineering Insights. Polymers (Basel) 2020; 12:E2909. [PMID: 33291646 PMCID: PMC7761984 DOI: 10.3390/polym12122909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022] Open
Abstract
Proteasomal degradation provides the crucial machinery for maintaining cellular proteostasis. The biological origins of modulation or impairment of the function of proteasomal complexes may include changes in gene expression of their subunits, ubiquitin mutation, or indirect mechanisms arising from the overall impairment of proteostasis. However, changes in the physico-chemical characteristics of the cellular environment might also meaningfully contribute to altered performance. This review summarizes the effects of physicochemical factors in the cell, such as pH, temperature fluctuations, and reactions with the products of oxidative metabolism, on the function of the proteasome. Furthermore, evidence of the direct interaction of proteasomal complexes with protein aggregates is compared against the knowledge obtained from immobilization biotechnologies. In this regard, factors such as the structures of the natural polymeric scaffolds in the cells, their content of reactive groups or the sequestration of metal ions, and processes at the interface, are discussed here with regard to their influences on proteasomal function.
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Affiliation(s)
- Lucia Račková
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia;
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Lei K, Bai H, Sun S, Xin C, Li J, Chen Q. PA28γ, an Accomplice to Malignant Cancer. Front Oncol 2020; 10:584778. [PMID: 33194729 PMCID: PMC7662426 DOI: 10.3389/fonc.2020.584778] [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: 07/18/2020] [Accepted: 10/12/2020] [Indexed: 02/05/2023] Open
Abstract
PA28γ is a nuclear activator of the 20S proteasome, which is involved in the regulation of several essential cellular processes and angiogenesis. Over the past 20 years, many amino acid sites and motifs have been proven to play important roles in the characteristic functions of PA28γ. The number of binding partners and validated cellular functions of PA28γ have increased, which has facilitated the clarification of its involvement in different biological events. PA28γ is involved in the progression of various diseases, and its aberrant overexpression in cancer is remarkable. Patients with low levels of PA28γ expression have a higher survival rate than those with high levels of PA28γ expression, as has been shown for a wide variety of tumors. The functions of PA28γ in cancer can be divided into five main categories: cell proliferation, cell apoptosis, metastasis and invasion, cell nuclear dynamics that have relevance to angiogenesis, and viral infection. In this review, we focus on the role of PA28γ in cancer, summarizing its aberrant expression, prooncogenic effects and underlying mechanisms in various cancers, and we highlight the possible cancer-related applications of PA28γ, such as its potential use in the diagnosis, targeted treatment and prognostic assessment of cancer.
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Affiliation(s)
- Kexin Lei
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hetian Bai
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Silu Sun
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chuan Xin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qianming Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Wang X, Meul T, Meiners S. Exploring the proteasome system: A novel concept of proteasome inhibition and regulation. Pharmacol Ther 2020; 211:107526. [PMID: 32173559 DOI: 10.1016/j.pharmthera.2020.107526] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/08/2020] [Indexed: 12/13/2022]
Abstract
The proteasome is a well-identified therapeutic target for cancer treatment. It acts as the main protein degradation system in the cell and degrades key mediators of cell growth, survival and function. The term "proteasome" embraces a whole family of distinct complexes, which share a common proteolytic core, the 20S proteasome, but differ by their attached proteasome activators. Each of these proteasome complexes plays specific roles in the control of cellular function. In addition, distinct proteasome interacting proteins regulate proteasome activity in subcellular compartments and in response to cellular signals. Proteasome activators and regulators may thus serve as building blocks to fine-tune proteasome function in the cell according to cellular needs. Inhibitors of the proteasome, e.g. the FDA approved drugs Velcade™, Kyprolis™, Ninlaro™, inactivate the catalytic 20S core and effectively block protein degradation of all proteasome complexes in the cell resulting in inhibition of cell growth and induction of apoptosis. Efficacy of these inhibitors, however, is hampered by their pronounced cytotoxic side-effects as well as by the emerging development of resistance to catalytic proteasome inhibitors. Targeted inhibition of distinct buiding blocks of the proteasome system, i.e. proteasome activators or regulators, represents an alternative strategy to overcome these limitations. In this review, we stress the importance of the diversity of the proteasome complexes constituting an entire proteasome system. Our building block concept provides a rationale for the defined targeting of distinct proteasome super-complexes in disease. We thereby aim to stimulate the development of innovative therapeutic approaches beyond broad catalytic proteasome inhibition.
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Affiliation(s)
- Xinyuan Wang
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Thomas Meul
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Silke Meiners
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany.
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6
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Yang F, Zhu B, Liu J, Liu Y, Jiang C, Sheng Q, Qiu J, Nie Z. The effect of acetylation on the protein stability of BmApoLp-III in the silkworm, Bombyx mori. INSECT MOLECULAR BIOLOGY 2020; 29:104-111. [PMID: 31390480 DOI: 10.1111/imb.12613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 05/26/2019] [Accepted: 07/30/2019] [Indexed: 06/10/2023]
Abstract
Acetylation is an important, reversible posttranslational modification to a protein. In a previous study, we found that there were a large number of acetylated sites in various nutrient storage proteins of the silkworm haemolymph. In this study, we confirmed that acetylation can affect the stability of nutrient storage protein Bombyx mori apolipophorin-III (BmApoLp-III). First, the expression of BmApoLp-III could be upregulated when BmN cells were treated with the deacetylase inhibitor panobinostat (LBH589); similarly, the expression was downregulated when the cells were treated with the acetylase inhibitor C646. Furthermore, the increase in acetylation by LBH589 could inhibit the degradation and improve the accumulation of BmApoLp-III in BmN cells treated with cycloheximide and MG132 respectively. Moreover, we found that an increase in acetylation could decrease the ubiquitination of BmApoLp-III and vice versa; therefore, we predicted that acetylation could improve the stability of BmApoLp-III by competing for ubiquitination and inhibiting the protein degradation pathway mediated by ubiquitin. Additionally, BmApoLp-III had an antiapoptosis function that increased after LBH589 treatment, which might have been due to the improved protein stability after acetylation. These results have laid the foundation for further study on the mechanism of acetylation in regulating the storage and utilization of silkworm nutrition.
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Affiliation(s)
- F Yang
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - B Zhu
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - J Liu
- School of Forestry and Biotechnology, Zhejiang A&F University, Linan, China
| | - Y Liu
- Zhejiang Economic & Trade Polytechnic, Hangzhou, China
| | - C Jiang
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Q Sheng
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - J Qiu
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Z Nie
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
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7
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Coux O, Zieba BA, Meiners S. The Proteasome System in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:55-100. [DOI: 10.1007/978-3-030-38266-7_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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8
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Proteasome-dependent degradation of Smad7 is critical for lung cancer metastasis. Cell Death Differ 2019; 27:1795-1806. [PMID: 31767934 DOI: 10.1038/s41418-019-0459-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 12/22/2022] Open
Abstract
Lung cancer is one of the cancers with highest morbidity and mortality rates and the metastasis of lung cancer is a leading cause of death. Mechanisms of lung cancer metastasis are yet to be fully understood. Herein, we demonstrate that mice deficient for REGγ, a proteasome activator, exhibited a significant reduction in tumor size, numbers, and metastatic rate with prolonged survival in a conditional Kras/p53 mutant lung cancer model. REGγ enhanced the TGFβ-Smad signaling pathway by ubiquitin-ATP-independent degradation of Smad7, an inhibitor of the TGFβ pathway. Activated TGFβ signaling in REGγ-positive lung cancer cells led to diminished expression of E-cadherin, a biomarker of epithelial-mesenchymal transitions (EMT), and elevated mesenchymal markers compared with REGγ-deficient lung cancer cells. REGγ overexpression was found in lung cancer patients with metastasis, correlating with the reduction of E-Cadherin/Smad7 and a poor prognosis. Overall, our study indicates that REGγ promotes lung cancer metastasis by activating TGF-β signaling via degradation of Smad7. Thus, REGγ may serve as a novel therapeutic target for lung cancers with poor prognosis.
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Zhang Y, Liu S, Zuo Q, Wu L, Ji L, Zhai W, Xiao J, Chen J, Li X. Oxidative challenge enhances REGγ-proteasome-dependent protein degradation. Free Radic Biol Med 2015; 82:42-9. [PMID: 25656993 DOI: 10.1016/j.freeradbiomed.2015.01.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 01/22/2015] [Accepted: 01/24/2015] [Indexed: 12/24/2022]
Abstract
Elimination of oxidized proteins is important to cells as accumulation of damaged proteins causes cellular dysfunction, disease, and aging. Abundant evidence shows that the 20S proteasome is largely responsible for degradation of oxidative proteins in both ubiquitin-dependent and ubiquitin-independent pathways. However, the role of the REGγ-proteasome in degrading oxidative proteins remains unclear. Here, we focus on two of the well-known REGγ-proteasome substrates, p21(Waf1/Cip1) and hepatitis C virus (HCV) core protein, to analyze the impact of oxidative stress on REGγ-proteasome functions. We demonstrate that REGγ-proteasome is essential for oxidative stress-induced rapid degradation of p21 and HCV proteins. Silencing REGγ abrogated this response in multiple cell lines. Furthermore, pretreatment with proteasome inhibitor MG132 completely blunted oxidant-induced p21 degradation, indicating a proteasome-dependent action. Cellular oxidation promoted REGγ-proteasome-dependent trypsin-like activity by enhancing the interaction between REGγ and 20S proteasome. Antioxidant could counteract oxidation-induced protein degradation, indicating that REGγ-proteasome activity may be regulated by redox state. This study provides further insights into the actions of a unique proteasome pathway in response to an oxidative stress environment, implying a novel molecular basis for REGγ-proteasome functions in antioxidation.
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Affiliation(s)
- Yuanyuan Zhang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Shuang Liu
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China; Department of Hematology, Guangdong No. 2 People Provincial Hospital, No. 1, Shiliugang Rd, Guangzhou, Guangdong, 510317, China
| | - Qiuhong Zuo
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China; Baylor College of Medicine, Department of Molecular Physiology and Biophysics, One Baylor Plaza, Houston, TX 77030, USA
| | - Lin Wu
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Lei Ji
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Wanli Zhai
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Jianru Xiao
- Department of Orthopedic Oncology, Changzheng Hospital, The Second Military Medical University, 415 Fengyang Road, Shanghai 200003, China.
| | - Jiwu Chen
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China; School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China.
| | - Xiaotao Li
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Magni M, Ruscica V, Buscemi G, Kim JE, Nachimuthu BT, Fontanella E, Delia D, Zannini L. Chk2 and REGγ-dependent DBC1 regulation in DNA damage induced apoptosis. Nucleic Acids Res 2014; 42:13150-60. [PMID: 25361978 PMCID: PMC4245943 DOI: 10.1093/nar/gku1065] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 10/15/2014] [Indexed: 01/08/2023] Open
Abstract
Human DBC1 (Deleted in Breast Cancer 1; KIAA1967; CCAR2) is a protein implicated in the regulation of apoptosis, transcription and histone modifications. Upon DNA damage, DBC1 is phosphorylated by ATM/ATR on Thr454 and this modification increases its inhibitory interaction with SIRT1, leading to p53 acetylation and p53-dependent apoptosis. Here, we report that the inhibition of SIRT1 by DBC1 in the DNA damage response (DDR) also depends on Chk2, the transducer kinase that is activated by ATM upon DNA lesions and contributes to the spreading of DNA damage signal. Indeed we found that inactivation of Chk2 reduces DBC1-SIRT1 binding, thus preventing p53 acetylation and DBC1-induced apoptosis. These events are mediated by Chk2 phosphorylation of the 11S proteasome activator REGγ on Ser247, which increases REGγ-DBC1 interaction and SIRT1 inhibition. Overall our results clarify the mechanisms underlying the DBC1-dependent SIRT1 inhibition and link, for the first time, Chk2 and REGγ to the ATM-DBC1-SIRT1 axis.
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Affiliation(s)
- Martina Magni
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy
| | - Vincenzo Ruscica
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy
| | - Giacomo Buscemi
- Department of Biosciences, University of Milan, 20133 Milan, Italy
| | - Ja-Eun Kim
- Department of Pharmacology, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
| | | | - Enrico Fontanella
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy
| | - Domenico Delia
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy
| | - Laura Zannini
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy
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11
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Regulation of c-Myc protein stability by proteasome activator REGγ. Cell Death Differ 2014; 22:1000-11. [PMID: 25412630 DOI: 10.1038/cdd.2014.188] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 10/09/2014] [Accepted: 10/14/2014] [Indexed: 01/05/2023] Open
Abstract
c-Myc is a key transcriptional factor that has a prominent role in cell growth, differentiation and tumor development. Its protein levels are tightly controlled by ubiquitin-proteasome pathway and frequently deregulated in various cancers. Here, we report that the 11S proteasomal activator REGγ is a novel regulator of c-Myc abundance in cells. We showed that overexpression of wild-type REGγ, but not inactive mutants including N151Y and G250S, significantly promoted the degradation of c-Myc. Depletion of REGγ markedly increased the protein stability of c-Myc. REGγ interacts with the C-terminal region of c-Myc and regulates c-Myc protein turnover. Functionally, REGγ negatively regulates c-Myc-mediated cell proliferation. Interestingly, depletion of the Drosophila Reg homolog (dReg) in developing wings induced the upregulation of Drosophila Myc, which contributes to cell death. Collectively, these results suggest that REGγ proteasome has a conserved role in the regulation of Myc abundance in both mammalian cells and Drosophila.
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Cui Z, Scruggs SB, Gilda JE, Ping P, Gomes AV. Regulation of cardiac proteasomes by ubiquitination, SUMOylation, and beyond. J Mol Cell Cardiol 2013; 71:32-42. [PMID: 24140722 DOI: 10.1016/j.yjmcc.2013.10.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/21/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
Abstract
The ubiquitin-proteasome system (UPS) is the major intracellular degradation system, and its proper function is critical to the health and function of cardiac cells. Alterations in cardiac proteasomes have been linked to several pathological phenotypes, including cardiomyopathies, ischemia-reperfusion injury, heart failure, and hypertrophy. Defects in proteasome-dependent cellular protein homeostasis can be causal for the initiation and progression of certain cardiovascular diseases. Emerging evidence suggests that the UPS can specifically target proteins that govern pathological signaling pathways for degradation, thus altering downstream effectors and disease outcomes. Alterations in UPS-substrate interactions in disease occur, in part, due to direct modifications of 19S, 11S or 20S proteasome subunits. Post-translational modifications (PTMs) are one facet of this proteasomal regulation, with over 400 known phosphorylation sites, over 500 ubiquitination sites and 83 internal lysine acetylation sites, as well as multiple sites for caspase cleavage, glycosylation (such as O-GlcNAc modification), methylation, nitrosylation, oxidation, and SUMOylation. Changes in cardiac proteasome PTMs, which occur in ischemia and cardiomyopathies, are associated with changes in proteasome activity and proteasome assembly; however several features of this regulation remain to be explored. In this review, we focus on how some of the less common PTMs affect proteasome function and alter cellular protein homeostasis. This article is part of a Special Issue entitled "Protein Quality Control, the Ubiquitin Proteasome System, and Autophagy".
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Affiliation(s)
- Ziyou Cui
- Department of Neurobiology, Physiology and Behavior, University of California, Davis CA 95616, USA
| | - Sarah B Scruggs
- Department of Physiology, University of California, Los Angeles, CA 90095, USA
| | - Jennifer E Gilda
- Department of Neurobiology, Physiology and Behavior, University of California, Davis CA 95616, USA
| | - Peipei Ping
- Department of Physiology, University of California, Los Angeles, CA 90095, USA
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology and Behavior, University of California, Davis CA 95616, USA; Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA.
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Wang D, Fang C, Zong NC, Liem DA, Cadeiras M, Scruggs SB, Yu H, Kim AK, Yang P, Deng M, Lu H, Ping P. Regulation of acetylation restores proteolytic function of diseased myocardium in mouse and human. Mol Cell Proteomics 2013; 12:3793-802. [PMID: 24037710 DOI: 10.1074/mcp.m113.028332] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteasome complexes play essential roles in maintaining cellular protein homeostasis and serve fundamental roles in cardiac function under normal and pathological conditions. A functional detriment in proteasomal activities has been recognized as a major contributor to the progression of cardiovascular diseases. Therefore, approaches to restore proteolytic function within the setting of the diseased myocardium would be of great clinical significance. In this study, we discovered that the cardiac proteasomal activity could be regulated by acetylation. Histone deacetylase (HDAC) inhibitors (suberoylanilide hydroxamic acid and sodium valproate) enhanced the acetylation of 20S proteasome subunits in the myocardium and led to an elevation of proteolytic capacity. This regulatory paradigm was present in both healthy and acutely ischemia/reperfusion (I/R) injured murine hearts, and HDAC inhibition in vitro restored proteolytic capacities to baseline sham levels in injured hearts. This mechanism of regulation was also viable in failing human myocardium. With 20S proteasomal complexes purified from murine myocardium treated with HDAC inhibitors in vivo, we confirmed that acetylation of 20S subunits directly, at least in part, presents a molecular explanation for the improvement in function. Furthermore, using high-resolution LC-MS/MS, we unraveled the first cardiac 20S acetylome, which identified the acetylation of nine N-termini and seven internal lysine residues. Acetylation on four lysine residues and four N-termini on cardiac proteasomes were novel discoveries of this study. In addition, the acetylation of five lysine residues was inducible via HDAC inhibition, which correlated with the enhancement of 20S proteasomal activity. Taken as a whole, our investigation unveiled a novel mechanism of proteasomal function regulation in vivo and established a new strategy for the potential rescue of compromised proteolytic function in the failing heart using HDAC inhibitors.
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Affiliation(s)
- Ding Wang
- Department of Physiology, UCLA School of Medicine, Los Angeles, California 90095
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Dong S, Jia C, Zhang S, Fan G, Li Y, Shan P, Sun L, Xiao W, Li L, Zheng Y, Liu J, Wei H, Hu C, Zhang W, Chin YE, Zhai Q, Li Q, Liu J, Jia F, Mo Q, Edwards DP, Huang S, Chan L, O'Malley BW, Li X, Wang C. The REGγ proteasome regulates hepatic lipid metabolism through inhibition of autophagy. Cell Metab 2013; 18:380-91. [PMID: 24011073 PMCID: PMC3813599 DOI: 10.1016/j.cmet.2013.08.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 06/22/2013] [Accepted: 08/09/2013] [Indexed: 12/17/2022]
Abstract
The ubiquitin-proteasome and autophagy-lysosome systems are major proteolytic pathways, whereas function of the Ub-independent proteasome pathway is yet to be clarified. Here, we investigated roles of the Ub-independent REGγ-proteasome proteolytic system in regulating metabolism. We demonstrate that mice deficient for the proteasome activator REGγ exhibit dramatic autophagy induction and are protected against high-fat diet (HFD)-induced liver steatosis through autophagy. Molecularly, prevention of steatosis in the absence of REGγ entails elevated SirT1, a deacetylase regulating autophagy and metabolism. REGγ physically binds to SirT1, promotes its Ub-independent degradation, and inhibits its activity to deacetylate autophagy-related proteins, thereby inhibiting autophagy under normal conditions. Moreover, REGγ and SirT1 dissociate from each other through a phosphorylation-dependent mechanism under energy-deprived conditions, unleashing SirT1 to stimulate autophagy. These observations provide a function of the REGγ proteasome in autophagy and hepatosteatosis, underscoring mechanistically a crosstalk between the proteasome and autophagy degradation system in the regulation of lipid homeostasis.
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Affiliation(s)
- Shuxian Dong
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, Shanghai, 200241, China; Department of Molecular and Cellular Biology, Department of Medicine, The Dan L. Duncan Cancer Center, The Diabetes Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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