101
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Xu J, Zhou L, Ji L, Chen F, Fortmann K, Zhang K, Liu Q, Li K, Wang W, Wang H, Xie W, Wang Q, Liu J, Zheng B, Zhang P, Huang S, Shi T, Zhang B, Dang Y, Chen J, O'Malley BW, Moses RE, Wang P, Li L, Xiao J, Hoffmann A, Li X. The REGγ-proteasome forms a regulatory circuit with IκBɛ and NFκB in experimental colitis. Nat Commun 2016; 7:10761. [PMID: 26899380 PMCID: PMC4764899 DOI: 10.1038/ncomms10761] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/16/2016] [Indexed: 12/26/2022] Open
Abstract
Increasing incidence of inflammatory bowel disorders demands a better understanding of the molecular mechanisms underlying its multifactorial aetiology. Here we demonstrate that mice deficient for REGγ, a proteasome activator, show significantly attenuated intestinal inflammation and colitis-associated cancer in dextran sodium sulfate model. Bone marrow transplantation experiments suggest that REGγ's function in non-haematopoietic cells primarily contributes to the phenotype. Elevated expression of REGγ exacerbates local inflammation and promotes a reciprocal regulatory loop with NFκB involving ubiquitin-independent degradation of IκBɛ. Additional deletion of IκBɛ restored colitis phenotypes and inflammatory gene expression in REGγ-deficient mice. In sum, this study identifies REGγ-mediated control of IκBɛ as a molecular mechanism that contributes to NFκB activation and promotes bowel inflammation and associated tumour formation in response to chronic injury. REGγ is a component of ubiquitin-independent 20S proteasome that targets many regulatory proteins for degradation. Here the authors show that REGγ is induced in DSS colitis and promotes degradation of IκBɛ, and that REGγ-deficient mice have less NFκB activation and are more resistant to the disease.
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Affiliation(s)
- Jinjin Xu
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Lei Zhou
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 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, East China Normal University, Shanghai 200241, China
| | - Fengyuan Chen
- The Fifth Hospital of Shanghai, Fudan University, Shanghai 200240, China
| | - Karen Fortmann
- Signaling Systems Laboratory and San Diego Center for Systems Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.,Department of Microbiology, Immunology, and Molecular Genetics and Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, California 90025, USA
| | - Kun Zhang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Qingwu Liu
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Ke Li
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Weicang Wang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Hao Wang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Wei Xie
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Qingwei Wang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Jiang Liu
- The Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China
| | - Biao Zheng
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Pei Zhang
- Department of Pathology, the Second Chengdu Municipal Hospital, Chengdu 610017, China
| | - Shixia Huang
- Department of Molecular and Cellular Biology, The Dan L. Duncan Cancer Center, Baylor College of Medicine. One Baylor Plaza, Houston, Texas 77030, USA
| | - Tieliu Shi
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Biaohong Zhang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Yongyan Dang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Jiwu Chen
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Bert W O'Malley
- Department of Molecular and Cellular Biology, The Dan L. Duncan Cancer Center, Baylor College of Medicine. One Baylor Plaza, Houston, Texas 77030, USA
| | - Robb E Moses
- Department of Molecular and Cellular Biology, The Dan L. Duncan Cancer Center, Baylor College of Medicine. One Baylor Plaza, Houston, Texas 77030, USA
| | - Ping Wang
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Lei Li
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China
| | - Jianru Xiao
- Department of Orthopedic Oncology, Changzheng Hospital, The Second Military Medical University, 415 Fengyang Road, Shanghai 200003, China
| | - Alexander Hoffmann
- Signaling Systems Laboratory and San Diego Center for Systems Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Xiaotao Li
- Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, Shanghai 200241, China.,Department of Molecular and Cellular Biology, The Dan L. Duncan Cancer Center, Baylor College of Medicine. One Baylor Plaza, Houston, Texas 77030, USA
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102
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Feng X, Jiang Y, Xie L, Jiang L, Li J, Sun C, Xu H, Wang R, Zhou M, Zhou Y, Dan H, Wang Z, Ji N, Deng P, Liao G, Geng N, Wang Y, Zhang D, Lin Y, Ye L, Liang X, Li L, Luo G, Feng M, Fang J, Zeng X, Wang Z, Chen Q. Overexpression of proteasomal activator PA28α serves as a prognostic factor in oral squamous cell carcinoma. J Exp Clin Cancer Res 2016; 35:35. [PMID: 26892607 PMCID: PMC4759779 DOI: 10.1186/s13046-016-0309-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 02/11/2016] [Indexed: 02/05/2023] Open
Abstract
Background Despite recent advances in oral squamous cell carcinoma (OSCC) diagnosis and therapy, disease recurrence remains common and is strongly associated with mortality. It is therefore critical to identify new targets for both treatment and diagnostic purposes. We aimed at investigating the role of PA28α, a proteasomal activator in OSCC. Methods The expression of PA28α was examined in a panel of OSCC cell lines and tissues, associated with oncomine analysis. In a large OSCC patient cohort, the prognostic value of PA28α expression was evaluated. Primary clinical end points were recurrence-free and overall survival rate. Functional involvement of PA28α in OSCC was examined in both in vitro and in vivo models upon specific siRNA knockdown. Results PA28α was found to be overexpressed in OSCC cell lines and tumor tissues. High expression of PA28α was significantly associated with recurrence and poorer overall survival. Specific knockdown of PA28α inhibited OSCC cell proliferation, migration, invasion in vitro and reduced the growth of OSCC xenografts in vivo. Multivariate Cox regression analyses revealed PA28α as independent prognostic predictors. Conclusions These results suggest that PA28α is involved in OSCC oncogenesis and may serve as a potential prognostic factor. Electronic supplementary material The online version of this article (doi:10.1186/s13046-016-0309-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiaodong Feng
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Yuchen Jiang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Liang Xie
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Lu Jiang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Jing Li
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Chongkui Sun
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Hao Xu
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China. .,State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, China.
| | - Ruinan Wang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Min Zhou
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Yu Zhou
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Hongxia Dan
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Zhiyong Wang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Ning Ji
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Peng Deng
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Ga Liao
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Ning Geng
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Yun Wang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Dunfang Zhang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Yunfeng Lin
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Ling Ye
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Xinhua Liang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Longjiang Li
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Gang Luo
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou, China.
| | - Mingye Feng
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Juan Fang
- Guangdong Provincial Key Laboratory of Oral Diseases, Stomatological Hospital, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China.
| | - Xin Zeng
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
| | - Zhi Wang
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China. .,Guangdong Provincial Key Laboratory of Oral Diseases, Stomatological Hospital, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China.
| | - Qianming Chen
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No. 14, Sec.3, Renminnan Road, Chengdu, Sichuan, 610041, China.
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Sun J, Luan Y, Xiang D, Tan X, Chen H, Deng Q, Zhang J, Chen M, Huang H, Wang W, Niu T, Li W, Peng H, Li S, Li L, Tang W, Li X, Wu D, Wang P. The 11S Proteasome Subunit PSME3 Is a Positive Feedforward Regulator of NF-κB and Important for Host Defense against Bacterial Pathogens. Cell Rep 2016; 14:737-749. [PMID: 26776519 DOI: 10.1016/j.celrep.2015.12.069] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 10/18/2015] [Accepted: 12/11/2015] [Indexed: 01/01/2023] Open
Abstract
The NF-κB pathway plays important roles in immune responses. Although its regulation has been extensively studied, here, we report an unknown feedforward mechanism for the regulation of this pathway by Toll-like receptor (TLR) ligands in macrophages. During bacterial infections, TLR ligands upregulate the expression of the 11S proteasome subunit PSME3 via NF-κB-mediated transcription in macrophages. PSME3, in turn, enhances the transcriptional activity of NF-κB by directly binding to and destabilizing KLF2, a negative regulator of NF-κB transcriptional activity. Consistent with this positive role of PSME3 in NF-κB regulation and importance of the NF-κB pathway in host defense against bacterial infections, the lack of PSME3 in hematopoietic cells renders the hosts more susceptible to bacterial infections, accompanied by increased bacterial burdens in host tissues. Thus, this study identifies a substrate for PSME3 and elucidates a proteolysis-dependent, but ubiquitin-independent, mechanism for NF-κB regulation that is important for host defense and innate immunity.
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Affiliation(s)
- Jinxia Sun
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Yi Luan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Dong Xiang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Xiao Tan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Hui Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Qi Deng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Jiaojiao Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Minghui Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Hongjun Huang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Weichao Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Tingting Niu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Wenjie Li
- Emergency Department, Shanghai 10th People's Hospital, School of Medicine, Tongji University, Shanghai 200072, China
| | - Hu Peng
- Emergency Department, Shanghai 10th People's Hospital, School of Medicine, Tongji University, Shanghai 200072, China
| | - Shuangxi Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Lei Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Wenwen Tang
- Department of Central Laboratory, Shanghai 10th People's Hospital, School of Life Science and Technology, Tongji University, Shanghai 200072, China
| | - Xiaotao Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China.
| | - Dianqing Wu
- Department of Pharmacology, Yale School of Medicine, Yale University, New Haven, CT 06520, USA.
| | - Ping Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Department of Central Laboratory, Shanghai 10th People's Hospital, School of Life Science and Technology, Tongji University, Shanghai 200072, China.
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104
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Finley D, Chen X, Walters KJ. Gates, Channels, and Switches: Elements of the Proteasome Machine. Trends Biochem Sci 2015; 41:77-93. [PMID: 26643069 DOI: 10.1016/j.tibs.2015.10.009] [Citation(s) in RCA: 199] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/27/2015] [Accepted: 10/30/2015] [Indexed: 12/14/2022]
Abstract
The proteasome has emerged as an intricate machine that has dynamic mechanisms to regulate the timing of its activity, its selection of substrates, and its processivity. The 19-subunit regulatory particle (RP) recognizes ubiquitinated proteins, removes ubiquitin, and injects the target protein into the proteolytic chamber of the core particle (CP) via a narrow channel. Translocation into the CP requires substrate unfolding, which is achieved through mechanical force applied by a hexameric ATPase ring of the RP. Recent cryoelectron microscopy (cryoEM) studies have defined distinct conformational states of the RP, providing illustrative snapshots of what appear to be progressive steps of substrate engagement. Here, we bring together this new information with molecular analyses to describe the principles of proteasome activity and regulation.
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Affiliation(s)
- Daniel Finley
- Department of Cell Biology, Harvard Medical School, 240 Longwood Ave, Boston, MA 02115, USA.
| | - Xiang Chen
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Kylie J Walters
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
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105
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Buscemi G, Ricci C, Zannini L, Fontanella E, Plevani P, Delia D. Bimodal regulation of p21(waf1) protein as function of DNA damage levels. Cell Cycle 2015; 13:2901-12. [PMID: 25486478 PMCID: PMC4615108 DOI: 10.4161/15384101.2014.946852] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Human p21Waf1 protein is well known for being transcriptionally induced by p53 and activating the cell cycle checkpoint arrest in response to DNA breaks. Here we report that p21Waf1 protein undergoes a bimodal regulation, being upregulated in response to low doses of DNA damage but rapidly and transiently degraded in response to high doses of DNA lesions. Responsible for this degradation is the checkpoint kinase Chk1, which phosphorylates p21Waf1 on T145 and S146 residues and induces its proteasome-dependent proteolysis. The initial p21Waf1 degradation is then counteracted by the ATM-Chk2 pathway, which promotes the p53-dependent accumulation of p21Waf1 at any dose of damage. We also found that p21Waf1 ablation favors the activation of an apoptotic program to eliminate otherwise irreparable cells. These findings support a model in which in human cells a balance between ATM-Chk2-p53 and the ATR-Chk1 pathways modulates p21Waf1 protein levels in relation to cytostatic and cytotoxic doses of DNA damage.
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Affiliation(s)
- G Buscemi
- a Department of Experimental Oncology; Fondazione IRCCS Istituto Nazionale dei Tumori ; Milan , Italy
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106
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Li J, Feng X, Sun C, Zeng X, Xie L, Xu H, Li T, Wang R, Xu X, Zhou X, Zhou M, Zhou Y, Dan H, Wang Z, Ji N, Deng P, Liao G, Geng N, Wang Y, Zhang D, Lin Y, Ye L, Liang X, Li L, Luo G, Jiang L, Wang Z, Chen Q. Associations between proteasomal activator PA28γ and outcome of oral squamous cell carcinoma: Evidence from cohort studies and functional analyses. EBioMedicine 2015; 2:851-8. [PMID: 26425691 PMCID: PMC4563126 DOI: 10.1016/j.ebiom.2015.07.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 07/01/2015] [Accepted: 07/01/2015] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND PA28γ was suggested to play a role in malignant progression. This paper aimed to investigate the association between PA28γ and the prognosis of oral squamous cell carcinoma (OSCC) in cohort studies. METHODS The PA28γ expression level was assessed by immunohistochemistry in a total of 368 OSCC patients from three independent cohorts. The Cox proportional hazards regression model was used to determine multivariate hazard ratios for Overall Survival (OS). Model discrimination was measured using C Statistic. Additionally, OS was analyzed in Head Neck Squamous Cell Carcinoma (HNSCC) patients from The Cancer Genome Atlas (TCGA) data set. Functional analyses were conducted both in-vitro and in-vivo. FINDINGS The median follow-up times of patients in the three studies were 60, 52, and 51 months. High expression of PA28γ was identified in tumors from 179 of 368 patients (48.6%). Compared with low expression, high expression of PA28γ was strongly associated with worse OS, with relative risks of 5.14 (95% CI, 2.51-10.5; P < 0.001), 2.82 (95% CI, 1.73-4.61; P < 0.001), and 3.85 (95% CI, 1.59-9.37; P = 0.003). PA28γ expression was also associated with disease-free survival in all three cohorts (P < 0.005). These findings are consistent with TCGA HNSCC data (P < 0.006). The prediction of all-cause mortality was significantly improved when PA28γ was added to the traditional clinical factors (Model 3, C statistic value: 0.78 VS 0.73, P = 0.016). In functional analyses, we found that PA28γ silencing dramatically inhibited the growth, proliferation and mobility of OSCC cells in vitro and reduced tumor growth and angiogenesis in tumor-bearing mice. INTERPRETATION PA28γ overexpression is associated with adverse prognosis in patients with OSCC. The aberrant expression of PA28γ may contribute to the pathogenesis and progression of OSCC. RESEARCH IN CONTEXT OSCC is one of the most common HNSCC, which have a high lethally rate. However, few prognostic markers have been applied in the clinical practice. We found that PA28γ in OSCC tumor tissues were significantly high expression than those in normal tissues. As the results of the three cohorts from two independent research centers and from an additional validation cohort from a US population in the TCGA dataset, we demonstrate PA28γ is a good predictor of the risk of death in OSCC. Meanwhile, we demonstrate PA28γ have a potential role in OSCC tumorigenesis.
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Affiliation(s)
- Jing Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xiaodong Feng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chongkun Sun
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xin Zeng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Liang Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hao Xu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China ; West China School of Public health, Sichuan University, Chengdu, China
| | - Taiwen Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ruinan Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xiaoping Xu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xikun Zhou
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Min Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yu Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hongxia Dan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhiyong Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ning Ji
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Peng Deng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ga Liao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ning Geng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yun Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Dunfang Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yunfeng Lin
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ling Ye
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xinhua Liang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Longjiang Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Gang Luo
- Guangdong Provincial Stomatological Hospital & the Affiliated Stomatological Hospital of Southern Medical University, Guangzhou, China
| | - Lu Jiang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhi Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qianming Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Abstract
All living organisms require protein degradation to terminate biological processes and remove damaged proteins. One such machine is the 20S proteasome, a specialized barrel-shaped and compartmentalized multicatalytic protease. The activity of the 20S proteasome generally requires the binding of regulators/proteasome activators (PAs), which control the entrance of substrates. These include the PA700 (19S complex), which assembles with the 20S and forms the 26S proteasome and allows the efficient degradation of proteins usually labeled by ubiquitin tags, PA200 and PA28, which are involved in proteolysis through ubiquitin-independent mechanisms and PI31, which was initially identified as a 20S inhibitor in vitro. Unlike 20S proteasome, shown to be present in all Eukaryotes and Archaea, the evolutionary history of PAs remained fragmentary. Here, we made a comprehensive survey and phylogenetic analyses of the four types of regulators in 17 clades covering most of the eukaryotic supergroups. We found remarkable conservation of each PA700 subunit in all eukaryotes, indicating that the current complex PA700 structure was already set up in the last eukaryotic common ancestor (LECA). Also present in LECA, PA200, PA28, and PI31 showed a more contrasted evolutionary picture, because many lineages have subsequently lost one or two of them. The paramount conservation of PA700 composition in all eukaryotes and the dynamic evolution of PA200, PA28, and PI31 are discussed in the light of current knowledge on their physiological roles.
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Affiliation(s)
- Philippe Fort
- CNRS, CRBM, UMR5237, Montpellier, France Université de Montpellier, France
| | - Andrey V Kajava
- CNRS, CRBM, UMR5237, Montpellier, France Université de Montpellier, France Institut de Biologie Computationnelle, Montpellier, France
| | - Fredéric Delsuc
- Université de Montpellier, France CNRS, IRD, Institut des Sciences de l'Evolution, UMR 5554, Montpellier, France
| | - Olivier Coux
- CNRS, CRBM, UMR5237, Montpellier, France Université de Montpellier, France
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108
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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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109
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Mutant p53 (p53-R248Q) functions as an oncogene in promoting endometrial cancer by up-regulating REGγ. Cancer Lett 2015; 360:269-79. [DOI: 10.1016/j.canlet.2015.02.028] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 11/17/2022]
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110
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XU XIAOPING, LIU DONGJUAN, JI NING, LI TAIWEN, LI LONGJIANG, JIANG LU, LI JING, ZHANG PING, ZENG XIN, CHEN QIANMING. A novel transcript variant of proteasome activator 28γ: Identification and function in oral cancer cells. Int J Oncol 2015; 47:188-94. [DOI: 10.3892/ijo.2015.2980] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/04/2015] [Indexed: 11/06/2022] Open
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111
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REGγ is critical for skin carcinogenesis by modulating the Wnt/β-catenin pathway. Nat Commun 2015; 6:6875. [PMID: 25908095 DOI: 10.1038/ncomms7875] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 03/09/2015] [Indexed: 12/17/2022] Open
Abstract
Here we report that mice deficient for the proteasome activator, REGγ, exhibit a marked resistance to TPA (12-O-tetradecanoyl-phorbol-13-acetate)-induced keratinocyte proliferation, epidermal hyperplasia and onset of papillomas compared with wild-type counterparts. Interestingly, a massive increase of REGγ in skin tissues or cells resulting from TPA induces activation of p38 mitogen-activated protein kinase (MAPK/p38). Blocking p38 MAPK activation prevents REGγ elevation in HaCaT cells with TPA treatment. AP-1, the downstream effector of MAPK/p38, directly binds to the REGγ promoter and activates its transcription in response to TPA stimulation. Furthermore, we find that REGγ activates Wnt/β-catenin signalling by degrading GSK-3β in vitro and in cells, increasing levels of CyclinD1 and c-Myc, the downstream targets of β-catenin. Conversely, MAPK/p38 inactivation or REGγ deletion prevents the increase of cyclinD1 and c-Myc by TPA. This study demonstrates that REGγ acts in skin tumorigenesis mediating MAPK/p38 activation of the Wnt/β-catenin pathway.
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112
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Jastrab JB, Wang T, Murphy JP, Bai L, Hu K, Merkx R, Huang J, Chatterjee C, Ovaa H, Gygi SP, Li H, Darwin KH. An adenosine triphosphate-independent proteasome activator contributes to the virulence of Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2015; 112:E1763-72. [PMID: 25831519 PMCID: PMC4394314 DOI: 10.1073/pnas.1423319112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mycobacterium tuberculosis encodes a proteasome that is highly similar to eukaryotic proteasomes and is required to cause lethal infections in animals. The only pathway known to target proteins for proteasomal degradation in bacteria is pupylation, which is functionally analogous to eukaryotic ubiquitylation. However, evidence suggests that the M. tuberculosis proteasome contributes to pupylation-independent pathways as well. To identify new proteasome cofactors that might contribute to such pathways, we isolated proteins that bound to proteasomes overproduced in M. tuberculosis and found a previously uncharacterized protein, Rv3780, which formed rings and capped M. tuberculosis proteasome core particles. Rv3780 enhanced peptide and protein degradation by proteasomes in an adenosine triphosphate (ATP)-independent manner. We identified putative Rv3780-dependent proteasome substrates and found that Rv3780 promoted robust degradation of the heat shock protein repressor, HspR. Importantly, an M. tuberculosis Rv3780 mutant had a general growth defect, was sensitive to heat stress, and was attenuated for growth in mice. Collectively, these data demonstrate that ATP-independent proteasome activators are not confined to eukaryotes and can contribute to the virulence of one the world's most devastating pathogens.
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Affiliation(s)
- Jordan B Jastrab
- Department of Microbiology, New York University School of Medicine, New York, NY 10016
| | - Tong Wang
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973
| | - J Patrick Murphy
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Lin Bai
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973
| | - Kuan Hu
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794
| | - Remco Merkx
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; and
| | - Jessica Huang
- Department of Chemistry, University of Washington, Seattle, WA 98195
| | | | - Huib Ovaa
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; and
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Huilin Li
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794
| | - K Heran Darwin
- Department of Microbiology, New York University School of Medicine, New York, NY 10016;
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113
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Shi Y, Luo X, Li P, Tan J, Wang X, Xiang T, Ren G. miR-7-5p suppresses cell proliferation and induces apoptosis of breast cancer cells mainly by targeting REGγ. Cancer Lett 2015; 358:27-36. [DOI: 10.1016/j.canlet.2014.12.014] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/05/2014] [Accepted: 12/05/2014] [Indexed: 02/07/2023]
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114
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Saez I, Vilchez D. Protein clearance mechanisms and their demise in age-related neurodegenerative diseases. AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.1.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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115
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Sánchez-Lanzas R, Castaño JG. Proteins directly interacting with mammalian 20S proteasomal subunits and ubiquitin-independent proteasomal degradation. Biomolecules 2014; 4:1140-54. [PMID: 25534281 PMCID: PMC4279173 DOI: 10.3390/biom4041140] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Revised: 11/25/2014] [Accepted: 12/11/2014] [Indexed: 12/12/2022] Open
Abstract
The mammalian 20S proteasome is a heterodimeric cylindrical complex (α7β7β7α7), composed of four rings each composed of seven different α or β subunits with broad proteolytic activity. We review the mammalian proteins shown to directly interact with specific 20S proteasomal subunits and those subjected to ubiquitin-independent proteasomal degradation (UIPD). The published reports of proteins that interact with specific proteasomal subunits, and others found on interactome databases and those that are degraded by a UIPD mechanism, overlap by only a few protein members. Therefore, systematic studies of the specificity of the interactions, the elucidation of the protein regions implicated in the interactions (that may or may not be followed by degradation) and competition experiments between proteins known to interact with the same proteasomal subunit, are needed. Those studies should provide a coherent picture of the molecular mechanisms governing the interactions of cellular proteins with proteasomal subunits, and their relevance to cell proteostasis and cell functioning.
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Affiliation(s)
- Raúl Sánchez-Lanzas
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas 'Alberto Sols', UAM-CSIC, Facultad de Medicina de la Universidad Autónoma de Madrid, Madrid 28029, Spain.
| | - José G Castaño
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas 'Alberto Sols', UAM-CSIC, Facultad de Medicina de la Universidad Autónoma de Madrid, Madrid 28029, Spain.
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116
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Meiners S, Keller IE, Semren N, Caniard A. Regulation of the proteasome: evaluating the lung proteasome as a new therapeutic target. Antioxid Redox Signal 2014; 21:2364-82. [PMID: 24437504 DOI: 10.1089/ars.2013.5798] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Lung diseases are on the second rank worldwide with respect to morbidity and mortality. For most respiratory diseases, no effective therapies exist. Whereas the proteasome has been successfully evaluated as a novel target for therapeutic interventions in cancer, neurodegenerative, and cardiac disorders, there is a profound lack of knowledge on the regulation of proteasome activity in chronic and acute lung diseases. RECENT ADVANCES There are various means of how the amount of active proteasome complexes in the cell can be regulated such as transcriptional regulation of proteasomal subunit expression, association with different regulators, assembly and half-life of proteasomes and regulatory complexes, as well as post-translational modifications. It also becomes increasingly evident that proteasome activity is fine-tuned and depends on the state of the cell. We propose here that 20S proteasomes and their regulators can be regarded as dynamic building blocks, which assemble or disassemble in response to cellular needs. The composition of proteasome complexes in a cell may vary depending on tissue, cell type and compartment, stage of development, or pathological context. CRITICAL ISSUES AND FUTURE DIRECTIONS Dissecting the expression and regulation of the various catalytic forms of 20S proteasomes, such as constitutive, immuno-, and mixed proteasomes, together with their associated regulatory complexes will not only greatly enhance our understanding of proteasome function in lung pathogenesis but will also pave the way to develop new classes of drugs that inhibit or activate proteasome function in a defined setting for treatment of lung diseases.
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Affiliation(s)
- Silke Meiners
- Comprehensive Pneumology Center (CPC), University Hospital , Ludwig-Maximilians University, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
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117
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Kaake RM, Kao A, Yu C, Huang L. Characterizing the dynamics of proteasome complexes by proteomics approaches. Antioxid Redox Signal 2014; 21:2444-56. [PMID: 24423446 PMCID: PMC4241863 DOI: 10.1089/ars.2013.5815] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
SIGNIFICANCE The proteasome is the degradation machine of the ubiquitin-proteasome system, which is critical in controlling many essential biological processes. Aberrant regulation of proteasome-dependent protein degradation can lead to various human diseases, and general proteasome inhibitors have shown efficacy for cancer treatments. Though clinically effective, current proteasome inhibitors have detrimental side effects and, thus, better therapeutic strategies targeting proteasomes are needed. Therefore, a comprehensive characterization of proteasome complexes will provide the molecular details that are essential for developing new and improved drugs. RECENT ADVANCES New mass spectrometry (MS)-based proteomics approaches have been developed to study protein interaction networks and structural topologies of proteasome complexes. The results have helped define the dynamic proteomes of proteasome complexes, thus providing new insights into the mechanisms underlying proteasome function and regulation. CRITICAL ISSUES The proteasome exists as heterogeneous populations in tissues/cells, and its proteome is highly dynamic and complex. In addition, proteasome complexes are regulated by various mechanisms under different physiological conditions. Consequently, complete proteomic profiling of proteasome complexes remains a major challenge for the field. FUTURE DIRECTIONS We expect that proteomic methodologies enabling full characterization of proteasome complexes will continue to evolve. Further advances in MS instrumentation and protein separation techniques will be needed to facilitate the detailed proteomic analysis of low-abundance components and subpopulations of proteasome complexes. The results will help us understand proteasome biology as well as provide new therapeutic targets for disease diagnostics and treatment.
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Affiliation(s)
- Robyn M Kaake
- Department of Physiology and Biophysics, University of California , Irvine, Irvine, California
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118
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Gruner M, Moncsek A, Rödiger S, Kühnhardt D, Feist E, Stohwasser R. Increased proteasome activator 28 gamma (PA28γ) levels are unspecific but correlate with disease activity in rheumatoid arthritis. BMC Musculoskelet Disord 2014; 15:414. [PMID: 25482151 PMCID: PMC4295294 DOI: 10.1186/1471-2474-15-414] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 11/28/2014] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND PA28γ (also known as Ki, REG gamma, PMSE3), a member of the ubiquitin-and ATP-independent proteasome activator family 11S, has been proved to show proteasome-dependent and -independent effects on several proteins including tumor suppressor p53, cyclin-dependent kinase inhibitor p21 and steroid receptor co-activator 3 (SCR-3). Interestingly, PA28γ is overexpressed in pathological tissue of various cancers affecting e. g. breast, bowl and thyroids. Furthermore, anti-PA28γ autoantibodies have been linked to several autoimmune disorders. The aim of this study was to develop and evaluate a novel and sensitive PA28γ sandwich ELISA for the quantification of PA28γ serum levels in patients with cancer and autoimmune diseases for diagnostic and prognostic purposes. METHODS PA28γ-specific polyclonal antibodies and recombinant His-tagged PA28γ were purified and used to develop a sandwich ELISA for the detection of circulating PA28γ. With this new assay, PA28γ serum levels of patients with various cancers, rheumatoid arthritis (RA), Sjögren's syndrome (SS), adult-onset Still's disease (AOSD) and different connective-tissue diseases (CTD) were compared with healthy control subjects. Anti-PA28γ autoantibodies were additionally confirmed using a newly developed microbead assay. RESULTS The developed PA28γ sandwich ELISA showed a high specificity with a detection limit of 3 ng/ml. A significant up-regulation of circulating PA28γ was detected in the sera of patients with cancer, RA, SS and CTD. A significant correlation was observed dependent on age as well as anti-PA28γ autoantibody levels with circulating PA28γ protein levels. Furthermore, PA28γ serum levels showed a correlation with disease activity in patients with RA under treatment with the T-cell directed biological compound abatacept according to disease activity score 28 (DAS28) and erythrocyte sedimentation rate (ESR). CONCLUSION The application of PA28γ as a novel biomarker for diagnostic purposes of a specific disease is limited, since elevated levels were observed in different disorders. However, the correlation with disease activity in patients with RA suggests a prognostic value, which needs to be addressed by further studies. Therefore our results show that PA28γ is a useful marker which should be included in studies related to novel treatments, e.g. abatacept.
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Affiliation(s)
- Melanie Gruner
- />Faculty of Natural Sciences, Brandenburg Technical University Cottbus - Senftenberg, Großenhainer Str. 57, D-01968 Senftenberg, Germany
- />Department of Rheumatology and Clinical Immunology and Autoinflammatory Reference Centre at Charité, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Anja Moncsek
- />Faculty of Natural Sciences, Brandenburg Technical University Cottbus - Senftenberg, Großenhainer Str. 57, D-01968 Senftenberg, Germany
- />Department of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Stefan Rödiger
- />Faculty of Natural Sciences, Brandenburg Technical University Cottbus - Senftenberg, Großenhainer Str. 57, D-01968 Senftenberg, Germany
| | - Dagmar Kühnhardt
- />Department of Hematology and Oncology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Eugen Feist
- />Department of Rheumatology and Clinical Immunology and Autoinflammatory Reference Centre at Charité, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Ralf Stohwasser
- />Faculty of Natural Sciences, Brandenburg Technical University Cottbus - Senftenberg, Großenhainer Str. 57, D-01968 Senftenberg, Germany
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119
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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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120
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Proteasome subtypes and regulators in the processing of antigenic peptides presented by class I molecules of the major histocompatibility complex. Biomolecules 2014; 4:994-1025. [PMID: 25412285 PMCID: PMC4279167 DOI: 10.3390/biom4040994] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/02/2014] [Accepted: 10/29/2014] [Indexed: 02/07/2023] Open
Abstract
The proteasome is responsible for the breakdown of cellular proteins. Proteins targeted for degradation are allowed inside the proteasome particle, where they are cleaved into small peptides and released in the cytosol to be degraded into amino acids. In vertebrates, some of these peptides escape degradation in the cytosol, are loaded onto class I molecules of the major histocompatibility complex (MHC) and displayed at the cell surface for scrutiny by the immune system. The proteasome therefore plays a key role for the immune system: it provides a continued sampling of intracellular proteins, so that CD8-positive T-lymphocytes can kill cells expressing viral or tumoral proteins. Consequently, the repertoire of peptides displayed by MHC class I molecules at the cell surface depends on proteasome activity, which may vary according to the presence of proteasome subtypes and regulators. Besides standard proteasomes, cells may contain immunoproteasomes, intermediate proteasomes and thymoproteasomes. Cells may also contain regulators of proteasome activity, such as the 19S, PA28 and PA200 regulators. Here, we review the effects of these proteasome subtypes and regulators on the production of antigenic peptides. We also discuss an unexpected function of the proteasome discovered through the study of antigenic peptides: its ability to splice peptides.
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121
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Zhou X, Hao Q, Zhang Q, Liao JM, Ke JW, Liao P, Cao B, Lu H. Ribosomal proteins L11 and L5 activate TAp73 by overcoming MDM2 inhibition. Cell Death Differ 2014; 22:755-66. [PMID: 25301064 DOI: 10.1038/cdd.2014.167] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 01/08/2023] Open
Abstract
Over the past decade, a number of ribosomal proteins (RPs) have been found to have a role in activating the tumor suppressor p53 by directly binding to MDM2 and impeding its activity toward p53. Herein, we report that RPL5 and RPL11 can also enhance the transcriptional activity of a p53 homolog TAp73, but through a distinct mechanism. Interestingly, even though RPL5 and RPL11 were not shown to bind to p53, they were able to directly associate with the transactivation domain of TAp73 independently of MDM2 in response to RS. This association led to perturbation of the MDM2-TAp73 interaction, consequently preventing MDM2 from its association with TAp73 target gene promoters. Furthermore, ectopic expression of RPL5 or RPL11 markedly induced TAp73 transcriptional activity by antagonizing MDM2 suppression. Conversely, ablation of either of the RPs compromised TAp73 transcriptional activity, as evident by the reduction of p21 and Puma expression, in response to 5-fluorouracil (5-FU). Consistently, overexpression of RPL5 or RPL11 enhanced, but knockdown of either of them hampered, TAp73-mediated apoptosis. Intriguingly, simultaneous knockdown of TAp73 and either of the RPs was required for rescuing the 5-FU-triggered S-phase arrest of p53-null tumor cells. These results demonstrate a novel mechanism underlying the inhibition of tumor cell proliferation and growth by these two RPs via TAp73 activation.
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Affiliation(s)
- X Zhou
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - Q Hao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - Q Zhang
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - J-M Liao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - J-W Ke
- 1] Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA [2] Department of Laboratory Medicine; Jiangxi Children's Hospital, Nanchang, Jiangxi, China
| | - P Liao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - B Cao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - H Lu
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
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122
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Ben-Nissan G, Sharon M. Regulating the 20S proteasome ubiquitin-independent degradation pathway. Biomolecules 2014; 4:862-84. [PMID: 25250704 PMCID: PMC4192676 DOI: 10.3390/biom4030862] [Citation(s) in RCA: 243] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 08/27/2014] [Accepted: 09/05/2014] [Indexed: 02/07/2023] Open
Abstract
For many years, the ubiquitin-26S proteasome degradation pathway was considered the primary route for proteasomal degradation. However, it is now becoming clear that proteins can also be targeted for degradation by the core 20S proteasome itself. Degradation by the 20S proteasome does not require ubiquitin tagging or the presence of the 19S regulatory particle; rather, it relies on the inherent structural disorder of the protein being degraded. Thus, proteins that contain unstructured regions due to oxidation, mutation, or aging, as well as naturally, intrinsically unfolded proteins, are susceptible to 20S degradation. Unlike the extensive knowledge acquired over the years concerning degradation by the 26S proteasome, relatively little is known about the means by which 20S-mediated proteolysis is controlled. Here, we describe our current understanding of the regulatory mechanisms that coordinate 20S proteasome-mediated degradation, and highlight the gaps in knowledge that remain to be bridged.
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Affiliation(s)
- Gili Ben-Nissan
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Michal Sharon
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 7610001, Israel.
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Winkler J, Ori A, Holzer K, Sticht C, Dauch D, Eiteneuer EM, Pinna F, Geffers R, Ehemann V, Andres-Pons A, Breuhahn K, Longerich T, Bermejo JL, Gretz N, Zender L, Schirmacher P, Beck M, Singer S. Prosurvival function of the cellular apoptosis susceptibility/importin-α1 transport cycle is repressed by p53 in liver cancer. Hepatology 2014; 60:884-95. [PMID: 24799195 DOI: 10.1002/hep.27207] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 05/02/2014] [Indexed: 01/05/2023]
Abstract
UNLABELLED Proteins of the karyopherin superfamily including importins and exportins represent an essential part of the nucleocytoplasmic transport machinery. However, the functional relevance and regulation of karyopherins in hepatocellular carcinoma (HCC) is poorly understood. Here we identified cellular apoptosis susceptibility (CAS, exportin-2) and its transport substrate importin-α1 (imp-α1) among significantly up-regulated transport factor genes in HCC. Disruption of the CAS/imp-α1 transport cycle by RNAi in HCC cell lines resulted in decreased tumor cell growth and increased apoptosis. The apoptotic phenotype upon CAS depletion could be recapitulated by direct knockdown of the X-linked inhibitor of apoptosis (XIAP) and partially reverted by XIAP overexpression. In addition, XIAP and CAS mRNA expression levels were correlated in HCC patient samples (r=0.463; P<0.01), supporting the in vivo relevance of our findings. Furthermore, quantitative mass spectrometry analyses of murine HCC samples (p53-/- versus p53+/+) indicated higher protein expression of CAS and imp-α1 in p53-/- tumors. Consistent with a role of p53 in regulating the CAS/imp-α1 transport cycle, we observed that both transport factors were repressed upon p53 induction in a p21-dependent manner. CONCLUSION The CAS/imp-α1 transport cycle is linked to XIAP and is required to maintain tumor cell survival in HCC. Moreover, CAS and imp-α1 are targets of p53-mediated repression, which represents a novel aspect of p53's ability to control tumor cell growth in hepatocarcinogenesis.
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Affiliation(s)
- Juliane Winkler
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
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Melesse M, Choi E, Hall H, Walsh MJ, Geer MA, Hall MC. Timely activation of budding yeast APCCdh1 involves degradation of its inhibitor, Acm1, by an unconventional proteolytic mechanism. PLoS One 2014; 9:e103517. [PMID: 25072887 PMCID: PMC4114781 DOI: 10.1371/journal.pone.0103517] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/02/2014] [Indexed: 11/29/2022] Open
Abstract
Regulated proteolysis mediated by the ubiquitin proteasome system is a fundamental and essential feature of the eukaryotic cell division cycle. Most proteins with cell cycle-regulated stability are targeted for degradation by one of two related ubiquitin ligases, the Skp1-cullin-F box protein (SCF) complex or the anaphase-promoting complex (APC). Here we describe an unconventional cell cycle-regulated proteolytic mechanism that acts on the Acm1 protein, an inhibitor of the APC activator Cdh1 in budding yeast. Although Acm1 can be recognized as a substrate by the Cdc20-activated APC (APCCdc20) in anaphase, APCCdc20 is neither necessary nor sufficient for complete Acm1 degradation at the end of mitosis. An APC-independent, but 26S proteasome-dependent, mechanism is sufficient for complete Acm1 clearance from late mitotic and G1 cells. Surprisingly, this mechanism appears distinct from the canonical ubiquitin targeting pathway, exhibiting several features of ubiquitin-independent proteasomal degradation. For example, Acm1 degradation in G1 requires neither lysine residues in Acm1 nor assembly of polyubiquitin chains. Acm1 was stabilized though by conditional inactivation of the ubiquitin activating enzyme Uba1, implying some requirement for the ubiquitin pathway, either direct or indirect. We identified an amino terminal predicted disordered region in Acm1 that contributes to its proteolysis in G1. Although ubiquitin-independent proteasome substrates have been described, Acm1 appears unique in that its sensitivity to this mechanism is strictly cell cycle-regulated via cyclin-dependent kinase (Cdk) phosphorylation. As a result, Acm1 expression is limited to the cell cycle window in which Cdk is active. We provide evidence that failure to eliminate Acm1 impairs activation of APCCdh1 at mitotic exit, justifying its strict regulation by cell cycle-dependent transcription and proteolytic mechanisms. Importantly, our results reveal that strict cell-cycle expression profiles can be established independent of proteolysis mediated by the APC and SCF enzymes.
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Affiliation(s)
- Michael Melesse
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Eunyoung Choi
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Hana Hall
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Michael J. Walsh
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - M. Ariel Geer
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Mark C. Hall
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
- Center for Cancer Research, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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125
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Liu S, Lai L, Zuo Q, Dai F, Wu L, Wang Y, Zhou Q, Liu J, Liu J, Li L, Lin Q, Creighton CJ, Costello MG, Huang S, Jia C, Liao L, Luo H, Fu J, Liu M, Yi Z, Xiao J, Li X. PKA turnover by the REGγ-proteasome modulates FoxO1 cellular activity and VEGF-induced angiogenesis. J Mol Cell Cardiol 2014; 72:28-38. [PMID: 24560667 PMCID: PMC4237316 DOI: 10.1016/j.yjmcc.2014.02.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 02/04/2014] [Accepted: 02/11/2014] [Indexed: 01/08/2023]
Abstract
The REGγ-proteasome serves as a short-cut for the destruction of certain intact mammalian proteins in the absence of ubiquitin- and ATP. The biological roles of the proteasome activator REGγ are not completely understood. Here we demonstrate that REGγ controls degradation of protein kinase A catalytic subunit-α (PKAca) both in primary human umbilical vein endothelial cells (HUVECs) and mouse embryonic fibroblast cells (MEFs). Accumulation of PKAca in REGγ-deficient HUVECs or MEFs results in phosphorylation and nuclear exclusion of the transcription factor FoxO1, indicating that REGγ is involved in preserving FoxO1 transcriptional activity. Consequently, VEGF-induced expression of the FoxO1 responsive genes, VCAM-1 and E-Selectin, was tightly controlled by REGγ in a PKA dependent manner. Functionally, REGγ is crucial for the migration of HUVECs. REGγ(-/-) mice display compromised VEGF-instigated neovascularization in cornea and aortic ring models. Implanted matrigel plugs containing VEGF in REGγ(-/-) mice induced fewer capillaries than in REGγ(+/+) littermates. Taken together, our study identifies REGγ as a novel angiogenic factor that plays an important role in VEGF-induced expression of VCAM-1 and E-Selectin by antagonizing PKA signaling. Identification of the REGγ-PKA-FoxO1 pathway in endothelial cells (ECs) provides another potential target for therapeutic intervention in vascular diseases.
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Affiliation(s)
- Shuang Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Department of Hematology, Guangdong No. 2 Provincial People's Hospital, No.1 Shiliugang Rd, Guangzhou, Guangdong 510317, China
| | - Li Lai
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Qiuhong Zuo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Fujun Dai
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Lin Wu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Yan Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Qingxia Zhou
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Jian Liu
- Department of Molecular and Cellular Biology, Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jiang Liu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China
| | - Lei Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Qingxiang Lin
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Chad J Creighton
- Department of Medicine, Dan L. Duncan Cancer Center Division of Biostatistics, Baylor College of Medicine, Houston, TX, USA
| | - Myra Grace Costello
- Department of Molecular and Cellular Biology, Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Shixia Huang
- Department of Molecular and Cellular Biology, Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Caifeng Jia
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Lujian Liao
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Honglin Luo
- The James Hogg Research Centre for Cardiovascular and Pulmonary Research, University of British Columbia-St. Paul's Hospital, 1081 Burrard St., Vancouver, British Columbia V6Z 1Y6, Canada
| | - Junjiang Fu
- Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Luzhou Medical College, Luzhou 646000, China
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Zhengfang Yi
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China.
| | - Jianru Xiao
- Department of Orthopaedic Oncology, Changzheng Hospital, The Second Military Medical University, 415 Fengyang Road, Shanghai 200003, China.
| | - Xiaotao Li
- Department of Molecular and Cellular Biology, Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Orthopaedic Oncology, Changzheng Hospital, The Second Military Medical University, 415 Fengyang Road, Shanghai 200003, China; Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China.
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126
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Cascio P. PA28αβ: the enigmatic magic ring of the proteasome? Biomolecules 2014; 4:566-84. [PMID: 24970231 PMCID: PMC4101498 DOI: 10.3390/biom4020566] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/15/2014] [Accepted: 06/08/2014] [Indexed: 11/16/2022] Open
Abstract
PA28αβ is a γ-interferon-induced 11S complex that associates with the ends of the 20S proteasome and stimulates in vitro breakdown of small peptide substrates, but not proteins or ubiquitin-conjugated proteins. In cells, PA28 also exists in larger complexes along with the 19S particle, which allows ATP-dependent degradation of proteins; although in vivo a large fraction of PA28 is present as PA28αβ-20S particles whose exact biological functions are largely unknown. Although several lines of evidence strongly indicate that PA28αβ plays a role in MHC class I antigen presentation, the exact molecular mechanisms of this activity are still poorly understood. Herein, we review current knowledge about the biochemical and biological properties of PA28αβ and discuss recent findings concerning its role in modifying the spectrum of proteasome's peptide products, which are important to better understand the molecular mechanisms and biological consequences of PA28αβ activity.
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Affiliation(s)
- Paolo Cascio
- Department of Veterinary Sciences, University of Turin, Grugliasco 10095, Italy.
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127
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Differential regulation of the REGγ-proteasome pathway by p53/TGF-β signalling and mutant p53 in cancer cells. Nat Commun 2014; 4:2667. [PMID: 24157709 PMCID: PMC3876931 DOI: 10.1038/ncomms3667] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/25/2013] [Indexed: 12/15/2022] Open
Abstract
Proteasome activity is frequently enhanced in cancer to accelerate metastasis and
tumorigenesis. REGγ, a proteasome
activator known to promote p53/p21/p16 degradation, is often overexpressed in cancer
cells. Here we show that p53/TGF-β
signalling inhibits the REGγ–20S proteasome pathway by repressing REGγ expression. Smad3 and p53 interact on the REGγ promoter via the p53RE/SBE region. Conversely, mutant p53 binds to the REGγ promoter and recruits p300. Importantly, mutant p53 prevents Smad3/N-CoR complex
formation on the REGγ promoter,
which enhances the activity of the REGγ–20S proteasome pathway and contributes to mutant
p53 gain of function. Depletion of
REGγ alters the cellular response
to p53/TGF-β signalling in drug
resistance, proliferation, cell cycle progression and proteasome activity. Moreover,
p53 mutations show a positive
correlation with REGγ expression in
cancer samples. These findings suggest that targeting REGγ–20S proteasome for cancer therapy may be applicable to
human tumours with abnormal p53/Smad
protein status. Furthermore, this study demonstrates a link between p53/TGF-β signalling and the REGγ–20S proteasome pathway, and provides
insight into the REGγ/p53 feedback loop. REGγ is a proteasome activator and is frequently overexpressed in
cancer cells. Here Ali et al. demonstrate that p53/TGF-β signalling inhibits
REGγ expression, whereas p53 mutations increase REGγ transcription, identifying a
gain of function for mutant p53.
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128
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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 2014; 71:32-42. [PMID: 24140722 PMCID: PMC3990655 DOI: 10.1016/j.yjmcc.2013.10.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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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129
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Less understood issues: p21Cip1 in mitosis and its therapeutic potential. Oncogene 2014; 34:1758-67. [DOI: 10.1038/onc.2014.133] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/16/2014] [Accepted: 04/16/2014] [Indexed: 12/18/2022]
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130
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Saez I, Vilchez D. The Mechanistic Links Between Proteasome Activity, Aging and Age-related Diseases. Curr Genomics 2014; 15:38-51. [PMID: 24653662 PMCID: PMC3958958 DOI: 10.2174/138920291501140306113344] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/13/2014] [Accepted: 01/15/2014] [Indexed: 01/17/2023] Open
Abstract
Damaged and misfolded proteins accumulate during the aging process, impairing cell function and tissue homeostasis. These perturbations to protein homeostasis (proteostasis) are hallmarks of age-related neurodegenerative disorders such as Alzheimer’s, Parkinson’s or Huntington’s disease. Damaged proteins are degraded by cellular clearance mechanisms such as the proteasome, a key component of the proteostasis network. Proteasome activity declines during aging, and proteasomal dysfunction is associated with late-onset disorders. Modulation of proteasome activity extends lifespan and protects organisms from symptoms associated with proteostasis disorders. Here we review the links between proteasome activity, aging and neurodegeneration. Additionally, strategies to modulate proteasome activity and delay the onset of diseases associated to proteasomal dysfunction are discussed herein.
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Affiliation(s)
- Isabel Saez
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Co-logne, Joseph Stelzmann Strasse 26, 50931 Cologne, Germany
| | - David Vilchez
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Co-logne, Joseph Stelzmann Strasse 26, 50931 Cologne, Germany
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131
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Tar K, Dange T, Yang C, Yao Y, Bulteau AL, Salcedo EF, Braigen S, Bouillaud F, Finley D, Schmidt M. Proteasomes associated with the Blm10 activator protein antagonize mitochondrial fission through degradation of the fission protein Dnm1. J Biol Chem 2014; 289:12145-12156. [PMID: 24604417 DOI: 10.1074/jbc.m114.554105] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conserved Blm10/PA200 activators bind to the proteasome core particle gate and facilitate turnover of peptides and unfolded proteins in vitro. We report here that Blm10 is required for the maintenance of functional mitochondria. BLM10 expression is induced 25-fold upon a switch from fermentation to oxidative metabolism. In the absence of BLM10, Saccharomyces cerevisiae cells exhibit a temperature-sensitive growth defect under oxidative growth conditions and produce colonies with dysfunctional mitochondria at high frequency. Loss of BLM10 leads to reduced respiratory capacity, increased mitochondrial oxidative damage, and reduced viability in the presence of oxidative stress or death stimuli. In the absence of BLM10, increased fragmentation of the mitochondrial network under oxidative stress is observed indicative of elevated activity of the mitochondrial fission machinery. The degradation of Dnm1, the main factor mediating mitochondrial fission, is impaired in the absence of BLM10 in vitro and in vivo. These data suggest that the mitochondrial functional and morphological changes observed are related to elevated Dnm1 levels. This hypothesis is supported by the finding that cells that constitutively overexpress DNM1 display the same mitochondrial defects as blm10Δ cells. The data are consistent with a model in which Blm10 proteasome-mediated turnover of Dnm1 is required for the maintenance of mitochondrial function and provides cytoprotection under conditions that induce increased mitochondrial damage and programmed cell death.
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Affiliation(s)
- Krisztina Tar
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Thomas Dange
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Ciyu Yang
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Yanhua Yao
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Anne-Laure Bulteau
- INSERM, Institute Cochin, 24 Rue du Faubourg Saint Jacques, 75014 Paris, France
| | | | - Stephen Braigen
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Frederic Bouillaud
- INSERM, Institute Cochin, 24 Rue du Faubourg Saint Jacques, 75014 Paris, France
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 10115
| | - Marion Schmidt
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461.
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132
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Wan ZX, Yuan DM, Zhuo YM, Yi X, Zhou J, Xu ZX, Zhou JL. The proteasome activator PA28γ, a negative regulator of p53, is transcriptionally up-regulated by p53. Int J Mol Sci 2014; 15:2573-84. [PMID: 24531141 PMCID: PMC3958868 DOI: 10.3390/ijms15022573] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 02/08/2014] [Accepted: 02/08/2014] [Indexed: 11/30/2022] Open
Abstract
PA28γ (also called REGγ, 11Sγ or PSME3) negatively regulates p53 activity by promoting its nuclear export and/or degradation. Here, using the RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) method, we identified the transcription start site of the PA28γ gene. Assessment with the luciferase assay demonstrated that the sequence -193 to +16 is the basal promoter. Three p53 binding sites were found within the PA28γ promoter utilizing a bioinformatics approach and were confirmed by chromatin immunoprecipitation and biotinylated DNA affinity precipitation experiments. The p53 protein promotes PA28γ transcription, and p53-stimulated transcription of PA28γ can be inhibited by PA28γ itself. Our results suggest that PA28γ and p53 form a negative feedback loop, which maintains the balance of p53 and PA28γ in cells.
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Affiliation(s)
- Zhen-Xing Wan
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
| | - Dong-Mei Yuan
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
| | - Yi-Ming Zhuo
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
| | - Xin Yi
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
| | - Ji Zhou
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
| | - Zao-Xu Xu
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
| | - Jian-Lin Zhou
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
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133
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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: 70] [Impact Index Per Article: 6.4] [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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134
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Schmidt M, Finley D. Regulation of proteasome activity in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:13-25. [PMID: 23994620 DOI: 10.1016/j.bbamcr.2013.08.012] [Citation(s) in RCA: 328] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 08/05/2013] [Accepted: 08/07/2013] [Indexed: 12/13/2022]
Abstract
The ubiquitin-proteasome system (UPS) is the primary selective degradation system in the nuclei and cytoplasm of eukaryotic cells, required for the turnover of myriad soluble proteins. The hundreds of factors that comprise the UPS include an enzymatic cascade that tags proteins for degradation via the covalent attachment of a poly-ubiquitin chain, and a large multimeric enzyme that degrades ubiquitinated proteins, the proteasome. Protein degradation by the UPS regulates many pathways and is a crucial component of the cellular proteostasis network. Dysfunction of the ubiquitination machinery or the proteolytic activity of the proteasome is associated with numerous human diseases. In this review we discuss the contributions of the proteasome to human pathology, describe mechanisms that regulate the proteolytic capacity of the proteasome, and discuss strategies to modulate proteasome function as a therapeutic approach to ameliorate diseases associated with altered UPS function. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- Marion Schmidt
- Albert Einstein College of Medicine, Department of Biochemistry, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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135
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REGγ deficiency promotes premature aging via the casein kinase 1 pathway. Proc Natl Acad Sci U S A 2013; 110:11005-10. [PMID: 23766372 DOI: 10.1073/pnas.1308497110] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Our recent studies suggest a role for the proteasome activator REG (11S regulatory particles, 28-kDa proteasome activator)γ in the regulation of tumor protein 53 (p53). However, the molecular details and in vivo biological significance of REGγ-p53 interplay remain elusive. Here, we demonstrate that REGγ-deficient mice develop premature aging phenotypes that are associated with abnormal accumulation of casein kinase (CK) 1δ and p53. Antibody array analysis led us to identify CK1δ as a direct target of REGγ. Silencing CK1δ or inhibition of CK1δ activity prevented decay of murine double minute (Mdm)2. Interestingly, a massive increase of p53 in REGγ(-/-) tissues is associated with reduced Mdm2 protein levels despite that Mdm2 transcription is enhanced. Allelic p53 haplodeficiency in REGγ-deficient mice attenuated premature aging features. Furthermore, introducing exogenous Mdm2 to REGγ(-/-) MEFs significantly rescues the phenotype of cellular senescence, thereby establishing a REGγ-CK1-Mdm2-p53 regulatory pathway. Given the conflicting evidence regarding the "antiaging" and "proaging" effects of p53, our results indicate a key role for CK1δ-Mdm2-p53 regulation in the cellular aging process. These findings reveal a unique model that mimics acquired aging in mammals and indicates that modulating the activity of the REGγ-proteasome may be an approach for intervention in aging-associated disorders.
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136
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Liu J, Wang Y, Li L, Zhou L, Wei H, Zhou Q, Liu J, Wang W, Ji L, Shan P, Wang Y, Yang Y, Jung SY, Zhang P, Wang C, Long W, Zhang B, Li X. Site-specific acetylation of the proteasome activator REGγ directs its heptameric structure and functions. J Biol Chem 2013; 288:16567-16578. [PMID: 23612972 PMCID: PMC3675592 DOI: 10.1074/jbc.m112.437129] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 04/22/2013] [Indexed: 12/22/2022] Open
Abstract
The proteasome activator REGγ has been reported to promote degradation of steroid receptor coactivator-3 and cyclin-dependent kinase inhibitors p21, p16, and p19 in a ubiquitin- and ATP-independent manner. A recent comparative analysis of REGγ expression in mouse and human tissues reveals a unique pattern of REGγ in specific cell types, suggesting undisclosed functions and biological importance of this molecule. Despite the emerging progress made in REGγ-related studies, how REGγ function is regulated remains to be explored. In this study, we report for the first time that REGγ can be acetylated mostly on its lysine 195 (Lys-195) residue by CREB binding protein (CBP), which can be reversed by sirtuin 1 (SIRT1) in mammalian cells. Site-directed mutagenesis abrogated acetylation at Lys-195 and significantly attenuated the capability of REGγ to degrade its target substrates, p21 and hepatitis C virus core protein. Mechanistically, acetylation at Lys-195 is important for the interactions between REGγ monomers and ultimately influences REGγ heptamerization. Biological analysis of cells containing REGγ-WT or REGγ-K195R mutant indicates an impact of acetylation on REGγ-mediated regulation of cell proliferation and cell cycle progression. These findings reveal a previously unknown mechanism in the regulation of REGγ assembly and activity, suggesting a potential venue for the intervention of the ubiquitin-independent REGγ proteasome activity.
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Affiliation(s)
- Jiang Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Ying Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Lei Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Li Zhou
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Haibin Wei
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Qingxia Zhou
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jian Liu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Weicang Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Lei Ji
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Peipei Shan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yan Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yuanyuan Yang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Sung Yun Jung
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Pei Zhang
- Department of Pathology, the Second Chengdu Municipal Hospital, Chengdu, Sichuan 610017, China
| | - Chuangui Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Weiwen Long
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Bianhong Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
| | - Xiaotao Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
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137
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Kumoi K, Satoh T, Murata K, Hiromoto T, Mizushima T, Kamiya Y, Noda M, Uchiyama S, Yagi H, Kato K. An archaeal homolog of proteasome assembly factor functions as a proteasome activator. PLoS One 2013; 8:e60294. [PMID: 23555947 PMCID: PMC3605417 DOI: 10.1371/journal.pone.0060294] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 02/25/2013] [Indexed: 12/20/2022] Open
Abstract
Assembly of the eukaryotic 20S proteasome is an ordered process involving several proteins operating as proteasome assembly factors including PAC1-PAC2 but archaeal 20S proteasome subunits can spontaneously assemble into an active cylindrical architecture. Recent bioinformatic analysis identified archaeal PAC1-PAC2 homologs PbaA and PbaB. However, it remains unclear whether such assembly factor-like proteins play an indispensable role in orchestration of proteasome subunits in archaea. We revealed that PbaB forms a homotetramer and exerts a dual function as an ATP-independent proteasome activator and a molecular chaperone through its tentacle-like C-terminal segments. Our findings provide insights into molecular evolution relationships between proteasome activators and assembly factors.
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Affiliation(s)
- Kentaro Kumoi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku Nagoya, Japan
| | - Tadashi Satoh
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku Nagoya, Japan
| | - Kazuyoshi Murata
- National Institute for Physiological Science, National Institutes of Natural Sciences, 5–1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan
| | - Takeshi Hiromoto
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku Nagoya, Japan
| | - Tsunehiro Mizushima
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku Nagoya, Japan
- Picobiology Institute, Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo, Japan
| | - Yukiko Kamiya
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan
| | - Masanori Noda
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
| | - Susumu Uchiyama
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
| | - Hirokazu Yagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku Nagoya, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku Nagoya, Japan
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan
- * E-mail:
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138
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Mulvey CM, Tudzarova S, Crawford M, Williams GH, Stoeber K, Godovac-Zimmermann J. Subcellular proteomics reveals a role for nucleo-cytoplasmic trafficking at the DNA replication origin activation checkpoint. J Proteome Res 2013; 12:1436-53. [PMID: 23320540 PMCID: PMC4261602 DOI: 10.1021/pr3010919] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Depletion of DNA replication initiation factors such as CDC7 kinase triggers the origin activation checkpoint in healthy cells and leads to a protective cell cycle arrest at the G1 phase of the mitotic cell division cycle. This protective mechanism is thought to be defective in cancer cells. To investigate how this checkpoint is activated and maintained in healthy cells, we conducted a quantitative SILAC analysis of the nuclear- and cytoplasmic-enriched compartments of CDC7-depleted fibroblasts and compared them to a total cell lysate preparation. Substantial changes in total abundance and/or subcellular location were detected for 124 proteins, including many essential proteins associated with DNA replication/cell cycle. Similar changes in protein abundance and subcellular distribution were observed for various metabolic processes, including oxidative stress, iron metabolism, protein translation and the tricarboxylic acid cycle. This is accompanied by reduced abundance of two karyopherin proteins, suggestive of reduced nuclear import. We propose that altered nucleo-cytoplasmic trafficking plays a key role in the regulation of cell cycle arrest. The results increase understanding of the mechanisms underlying maintenance of the DNA replication origin activation checkpoint and are consistent with our proposal that cell cycle arrest is an actively maintained process that appears to be distributed over various subcellular locations.
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Affiliation(s)
- Claire M. Mulvey
- Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Slavica Tudzarova
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Mark Crawford
- Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Gareth H. Williams
- Research Department of Pathology and UCL Cancer Institute, Rockefeller Building, University College London, University Street, London WC1E 6JJ, United Kingdom
| | - Kai Stoeber
- Research Department of Pathology and UCL Cancer Institute, Rockefeller Building, University College London, University Street, London WC1E 6JJ, United Kingdom
| | - Jasminka Godovac-Zimmermann
- Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom
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139
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Abstract
The proteasome refers to a collection of complexes centered on the 20S proteasome core particle (20S CP), a complex of 28 subunits that houses proteolytic sites in its hollow interior. Proteasomes are found in eukaryotes, archaea, and some eubacteria, and their activity is critical for many cellular pathways. Important recent advances include inhibitor binding studies and the structure of the immunoproteasome, whose specificity is altered by the incorporation of inducible catalytic subunits. The inherent repression of the 20S CP is relieved by the ATP-independent activators 11S and Blm10/PA200, whose structures reveal principles of proteasome mechanism. The structure of the ATP-dependent 19S regulatory particle, which mediates degradation of polyubiquitylated proteins, is being revealed by a combination of crystal or NMR structures of individual subunits and electron microscopy reconstruction of the intact complex. Other recent structural advances inform us about mechanisms of assembly and the role of conformational changes in the functional cycle.
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Affiliation(s)
- Erik Kish-Trier
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650, USA
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140
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Ubiquitin-independent proteasomal degradation of tumor suppressors by human cytomegalovirus pp71 requires the 19S regulatory particle. J Virol 2013; 87:4665-71. [PMID: 23408605 DOI: 10.1128/jvi.03301-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Proteasomes generally degrade substrates tagged with polyubiquitin chains. In rare cases, however, proteasomes can degrade proteins without prior ubiquitination. For example, the human cytomegalovirus (HCMV) pp71 protein induces the proteasome-dependent, ubiquitin-independent degradation of the retinoblastoma (Rb) and Daxx proteins. These transcriptional corepressors and tumor suppressors inhibit the expression of cellular or viral genes that are required for efficient viral replication. Proteasomes are composed of a 20S catalytic core with or without one or two activator complexes, of which there are four different types. Here, we show that only one of these activators, the 19S regulatory particle that normally participates in ubiquitin-dependent protein degradation, is required for pp71-mediated degradation of Rb and Daxx. We report the unique use of a well-established route of substrate delivery to the proteasome by a viral protein to promote infection.
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141
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Yamada K, Ono M, Perkins ND, Rocha S, Lamond AI. Identification and functional characterization of FMN2, a regulator of the cyclin-dependent kinase inhibitor p21. Mol Cell 2013; 49:922-33. [PMID: 23375502 PMCID: PMC3594747 DOI: 10.1016/j.molcel.2012.12.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 10/17/2012] [Accepted: 12/26/2012] [Indexed: 01/06/2023]
Abstract
The ARF tumor suppressor is a central component of the cellular defense against oncogene activation in mammals. p14ARF activates p53 by binding and inhibiting HDM2, resulting, inter alia, in increased transcription and expression of the cyclin-dependent kinase inhibitor p21 and consequent cell-cycle arrest. We analyzed the effect of p14ARF induction on nucleolar protein dynamics using SILAC mass spectrometry and have identified the human Formin-2 (FMN2) protein as a component of the p14ARF tumor suppressor pathway. We show that FMN2 is increased upon p14ARF induction at both the mRNA and the protein level via a NF-κB-dependent mechanism that is independent of p53. FMN2 enhances expression of the cell-cycle inhibitor p21 by preventing its degradation. FMN2 is also induced by activation of other oncogenes, hypoxia, and DNA damage. These results identify FMN2 as a crucial component in the regulation of p21 and consequent oncogene/stress-induced cell-cycle arrest in human cells.
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Affiliation(s)
- Kayo Yamada
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, UK
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142
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Characterization of the bipartite degron that regulates ubiquitin-independent degradation of thymidylate synthase. Biosci Rep 2013. [PMID: 23181752 PMCID: PMC3549573 DOI: 10.1042/bsr20120112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
TS (thymidylate synthase) is a key enzyme in the de novo biosynthesis of dTMP, and is indispensable for DNA replication. Previous studies have shown that intracellular degradation of the human enzyme [hTS (human thymidylate synthase)] is mediated by the 26S proteasome, and occurs in a ubiquitin-independent manner. Degradation of hTS is governed by a degron that is located at the polypeptide's N-terminus that is capable of promoting the destabilization of heterologous proteins to which it is attached. The hTS degron is bipartite, consisting of two subdomains: an IDR (intrinsically disordered region) that is highly divergent among mammalian species, followed by a conserved amphipathic α-helix (designated hA). In the present report, we have characterized the structure and function of the hTS degron in more detail. We have conducted a bioinformatic analysis of interspecies sequence variation exhibited by the IDR, and find that its hypervariability is not due to diversifying (or positive) selection; rather, it has been subjected to purifying (or negative) selection, although the intensity of such selection is relaxed or weakened compared with that exerted on the rest of the molecule. In addition, we have verified that both subdomains of the hTS degron are required for full activity. Furthermore, their co-operation does not necessitate that they are juxtaposed, but is maintained when they are physically separated. Finally, we have identified a 'cryptic' degron at the C-terminus of hTS, which is activated by the N-terminal degron and appears to function only under certain circumstances; its role in TS metabolism is not known.
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143
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Kravtsova-Ivantsiv Y, Ciechanover A. Non-canonical ubiquitin-based signals for proteasomal degradation. J Cell Sci 2012; 125:539-48. [PMID: 22389393 DOI: 10.1242/jcs.093567] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Regulated cellular proteolysis is mediated largely by the ubiquitin-proteasome system (UPS). It is a highly specific process that is time- (e.g. cell cycle), compartment- (e.g. nucleus or endoplasmic reticulum) and substrate quality- (e.g. denatured or misfolded proteins) dependent, and allows fast adaptation to changing conditions. Degradation by the UPS is carried out through two successive steps: the substrate is covalently tagged with ubiquitin and subsequently degraded by the 26S proteasome. The accepted 'canonical' signal for proteasomal recognition is a polyubiquitin chain that is anchored to a lysine residue in the target substrate, and is assembled through isopeptide bonds involving lysine 48 of ubiquitin. However, several 'non-canonical' ubiquitin-based signals for proteasomal targeting have also been identified. These include chains anchored to residues other than internal lysine in the substrates, chains assembled through linking residues other than lysine 48 in ubiquitin, and mixed chains made of both ubiquitin and a ubiquitin-like protein. Furthermore, some proteins can be degraded following modification by a single ubiquitin (monoubiquitylation) or multiple single ubiquitins (multiple monoubiquitylation). Finally, some proteins can be proteasomally degraded without prior ubiquitylation (the process is also often referred to as ubiquitination). In this Commentary, we describe these recent findings and discuss the possible physiological roles of these diverse signals. Furthermore, we discuss the possible impact of this signal diversity on drug development.
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Affiliation(s)
- Yelena Kravtsova-Ivantsiv
- Cancer and Vascular Biology Research Center, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Efron Street, Bat Galim, PO Box 9649, Haifa 31096, Israel.
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144
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Doueiri R, Anupam R, Kvaratskhelia M, Green KB, Lairmore MD, Green PL. Comparative host protein interactions with HTLV-1 p30 and HTLV-2 p28: insights into difference in pathobiology of human retroviruses. Retrovirology 2012; 9:64. [PMID: 22876852 PMCID: PMC3464894 DOI: 10.1186/1742-4690-9-64] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 07/11/2012] [Indexed: 02/02/2023] Open
Abstract
Background Human T lymphotropic virus type-1 (HTLV-1) and type 2 (HTLV-2) are closely related human retroviruses, but have unique disease associations. HTLV-1 is the causative agent of an aggressive T-cell leukemia known as adult T-cell leukemia (ATL), HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), and other inflammatory diseases. HTLV-2 infection has not been clearly associated with any disease condition. Although both viruses can transform T cells in vitro, the HTLV-1 provirus is mainly detected in CD4+ T cells whereas HTLV-2 is mainly detected in CD8+ T cells of infected individuals. HTLV-1 and HTLV-2 encode accessory proteins p30 and p28, respectively, which share partial amino acid homology and are required for viral persistence in vivo. The goal of this study was to identify host proteins interacting with p30 and p28 in order to understand their role in pathogenesis. Results Affinity-tag purification coupled with mass spectrometric (MS) analyses revealed 42 and 22 potential interacting cellular partners of p30 and p28, respectively. Of these, only three cellular proteins, protein arginine methyltransferase 5 (PRMT5), hnRNP K and 60 S ribosomal protein L8 were detected in both p30 and p28 fractions. To validate the proteomic results, four interacting proteins were selected for further analyses using immunoblot assays. In full agreement with the MS analysis two cellular proteins REGγ and NEAF-interacting protein 30 (NIP30) selectively interacted with p30 and not with p28; heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1) bound to p28 and not to p30; and PRMT5 interacted with both p30 and p28. Further studies demonstrated that reduced levels of PRMT5 resulted in decreased HTLV-2 viral gene expression whereas the viral gene expression of HTLV-1 was unchanged. Conclusion The comparisons of p30 and p28 host protein interaction proteome showed striking differences with some degree of overlap. PRMT5, one of the host proteins that interacted with both p30 and p28 differentially affected HTLV-1 and HTLV-2 viral gene expression suggesting that PRMT5 is involved at different stages of HTLV-1 and HTLV-2 biology. These findings suggest that distinct host protein interaction profiles of p30 and p28 could, in part, be responsible for differences in HTLV-1 and HTLV-2 pathobiology. This study provides new avenues of investigation into mechanisms of viral infection, tropism and persistence.
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Affiliation(s)
- Rami Doueiri
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA
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145
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Li LP, Cheng WB, Li H, Li W, Yang H, Wen DH, Tang YD. Expression of Proteasome Activator REGγ in Human Laryngeal Carcinoma and Associations with Tumor Suppressor Proteins. Asian Pac J Cancer Prev 2012; 13:2699-703. [DOI: 10.7314/apjcp.2012.13.6.2699] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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146
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Tsihlis ND, Kapadia MR, Vavra AK, Jiang Q, Fu B, Martinez J, Kibbe MR. Nitric oxide decreases activity and levels of the 11S proteasome activator PA28 in the vasculature. Nitric Oxide 2012; 27:50-8. [DOI: 10.1016/j.niox.2012.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 11/16/2022]
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147
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Lin YC, Chen HM, Chou IM, Chen AN, Chen CP, Young GH, Lin CT, Cheng CH, Chang SC, Juang RH. Plastidial starch phosphorylase in sweet potato roots is proteolytically modified by protein-protein interaction with the 20S proteasome. PLoS One 2012; 7:e35336. [PMID: 22506077 PMCID: PMC3323651 DOI: 10.1371/journal.pone.0035336] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 03/15/2012] [Indexed: 01/27/2023] Open
Abstract
Post-translational regulation plays an important role in cellular metabolism. Earlier studies showed that the activity of plastidial starch phosphorylase (Pho1) may be regulated by proteolytic modification. During the purification of Pho1 from sweet potato roots, we observed an unknown high molecular weight complex (HX) showing Pho1 activity. The two-dimensional gel electrophoresis, mass spectrometry, and reverse immunoprecipitation analyses showed that HX is composed of Pho1 and the 20S proteasome. Incubating sweet potato roots at 45°C triggers a stepwise degradation of Pho1; however, the degradation process can be partially inhibited by specific proteasome inhibitor MG132. The proteolytically modified Pho1 displays a lower binding affinity toward glucose 1-phosphate and a reduced starch-synthesizing activity. This study suggests that the 20S proteasome interacts with Pho1 and is involved in the regulation of the catalytic activity of Pho1 in sweet potato roots under heat stress conditions.
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Affiliation(s)
- Yi-Chen Lin
- Department of Biochemical Science and Technology, and Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan
| | - Han-Min Chen
- Department of Life Science, and Institute of Applied Science and Engineering, Catholic Fu-Jen University, Taipei, Taiwan
| | - I-Min Chou
- Department of Biochemical Science and Technology, and Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan
| | - An-Na Chen
- Department of Biochemical Science and Technology, and Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan
| | - Chia-Pei Chen
- Department of Biochemical Science and Technology, and Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan
| | - Guang-Huar Young
- Division of Nephrology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Chi-Tsai Lin
- Institute of Bioscience and Biotechnology, and Marine Center for Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
| | - Chiung-Hsiang Cheng
- Animal Cancer Research Center, Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
| | - Shih-Chung Chang
- Department of Biochemical Science and Technology, and Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan
- * E-mail: (SCC); (RHJ)
| | - Rong-Huay Juang
- Department of Biochemical Science and Technology, and Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan
- * E-mail: (SCC); (RHJ)
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Zhang M, Gan L, Ren GS. REGγ is a strong candidate for the regulation of cell cycle, proliferation and the invasion by poorly differentiated thyroid carcinoma cells. Braz J Med Biol Res 2012; 45:459-65. [PMID: 22415115 PMCID: PMC3854288 DOI: 10.1590/s0100-879x2012007500035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 02/28/2012] [Indexed: 11/22/2022] Open
Abstract
REGγ is a proteasome activator that facilitates the degradation of small peptides. Abnormally high expression of REGγ has been observed in thyroid carcinomas. The purpose of the present study was to explore the role of REGγ in poorly differentiated thyroid carcinoma (PDTC). For this purpose, small interfering RNA (siRNA) was introduced to down-regulate the level of REGγ in the PDTC cell line SW579. Down-regulation of REGγ at the mRNA and protein levels was confirmed by RT-PCR and Western blot analyses. FACS analysis revealed cell cycle arrest at the G1/S transition, the MTT assay showed inhibition of cell proliferation, and the Transwell assay showed restricted cell invasion. Furthermore, the expression of the p21 protein was increased, the expression of proliferating cell nuclear antigen (PCNA) protein decreased, and the expression of the p27 protein was unchanged as shown by Western blot analyses. REGγ plays a critical role in the cell cycle, proliferation and invasion of SW579 cells. The alteration of p21 and PCNA proteins related to the down-regulation of REGγ suggests that p21 and PCNA participate in the process of REGγ regulation of cell cycle progression and cell proliferation. Thus, targeting REGγ has a therapeutic potential in the management of PDTC patients.
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Affiliation(s)
- M Zhang
- Department of General Surgery, The First Affiliated Hospital, Chongqing Medical University, China
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149
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Levy-Barda A, Lerenthal Y, Davis AJ, Chung YM, Essers J, Shao Z, van Vliet N, Chen DJ, Hu MCT, Kanaar R, Ziv Y, Shiloh Y. Involvement of the nuclear proteasome activator PA28γ in the cellular response to DNA double-strand breaks. Cell Cycle 2011; 10:4300-10. [PMID: 22134242 DOI: 10.4161/cc.10.24.18642] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The DNA damage response (DDR) is a complex signaling network that leads to damage repair while modulating numerous cellular processes. DNA double-strand breaks (DSBs), a highly cytotoxic DNA lesion, activate this system most vigorously. The DSB response network is orchestrated by the ATM protein kinase, which phosphorylates key players in its various branches. Proteasome-mediated protein degradation plays an important role in the proteome dynamics following DNA damage induction. Here, we identify the nuclear proteasome activator PA28γ (REGγ; PSME3) as a novel DDR player. PA28γ depletion leads to cellular radiomimetic sensitivity and a marked delay in DSB repair. Specifically, PA28γ deficiency abrogates the balance between the two major DSB repair pathways--nonhomologous end-joining and homologous recombination repair. Furthermore, PA28γ is found to be an ATM target, being recruited to the DNA damage sites and required for rapid accumulation of proteasomes at these sites. Our data reveal a novel ATM-PA28γ-proteasome axis of the DDR that is required for timely coordination of DSB repair.
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Affiliation(s)
- Adva Levy-Barda
- The David and Inez Myers Laboratory for Cancer Genetics, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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150
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Yamada K, Tamamori-Adachi M, Goto I, Iizuka M, Yasukawa T, Aso T, Okazaki T, Kitajima S. Degradation of p21Cip1 through anaphase-promoting complex/cyclosome and its activator Cdc20 (APC/CCdc20) ubiquitin ligase complex-mediated ubiquitylation is inhibited by cyclin-dependent kinase 2 in cardiomyocytes. J Biol Chem 2011; 286:44057-44066. [PMID: 22045811 DOI: 10.1074/jbc.m111.236711] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cyclin-dependent kinase inhibitor p21Cip1 plays a crucial role in regulating cell cycle arrest and differentiation. It is known that p21Cip1 increases during terminal differentiation of cardiomyocytes, but its expression control and biological roles are not fully understood. Here, we show that the p21Cip1 protein is stabilized in cardiomyocytes after mitogenic stimulation, due to its increased CDK2 binding and inhibition of ubiquitylation. The APC/CCdc20 complex is shown to be an E3 ligase mediating ubiquitylation of p21Cip1 at the N terminus. CDK2, but not CDC2, suppressed the interaction of p21Cip1 with Cdc20, thereby leading to inhibition of anaphase-promoting complex/cyclosome and its activator Cdc20 (APC/CCdc20)-mediated p21Cip1 ubiquitylation. It was further demonstrated that p21Cip1 accumulation caused G2 arrest of cardiomyocytes that were forced to re-enter the cell cycle. Taken together, these data show that the stability of the p21Cip1 protein is actively regulated in terminally differentiated cardiomyocytes and plays a role in inhibiting their uncontrolled cell cycle progression. Our study provides a novel insight on the control of p21Cip1 by ubiquitin-mediated degradation and its implication in cell cycle arrest in terminal differentiation.
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Affiliation(s)
- Kazuhiko Yamada
- Laboratory of Genome Structure and Regulation, School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510
| | - Mimi Tamamori-Adachi
- Department of Biochemical Genetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510; Department of Biochemistry, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173-8605.
| | - Ikuko Goto
- Department of Biochemical Genetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510
| | - Masayoshi Iizuka
- Department of Biochemistry, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173-8605
| | - Takashi Yasukawa
- Department of Functional Genomics, Kochi Medical School, Kohasu, Oko-cho, Nankoku City, Kochi, 783-8505, Japan
| | - Teijiro Aso
- Department of Functional Genomics, Kochi Medical School, Kohasu, Oko-cho, Nankoku City, Kochi, 783-8505, Japan
| | - Tomoki Okazaki
- Department of Biochemistry, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173-8605
| | - Shigetaka Kitajima
- Laboratory of Genome Structure and Regulation, School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510; Department of Biochemical Genetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510
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