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Potapenko A, Davidson JM, Lee A, Laird AS. The deubiquitinase function of ataxin-3 and its role in the pathogenesis of Machado-Joseph disease and other diseases. Biochem J 2024; 481:461-480. [PMID: 38497605 PMCID: PMC11088879 DOI: 10.1042/bcj20240017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 03/19/2024]
Abstract
Machado-Joseph disease (MJD) is a devastating and incurable neurodegenerative disease characterised by progressive ataxia, difficulty speaking and swallowing. Consequently, affected individuals ultimately become wheelchair dependent, require constant care, and face a shortened life expectancy. The monogenic cause of MJD is expansion of a trinucleotide (CAG) repeat region within the ATXN3 gene, which results in polyglutamine (polyQ) expansion within the resultant ataxin-3 protein. While it is well established that the ataxin-3 protein functions as a deubiquitinating (DUB) enzyme and is therefore critically involved in proteostasis, several unanswered questions remain regarding the impact of polyQ expansion in ataxin-3 on its DUB function. Here we review the current literature surrounding ataxin-3's DUB function, its DUB targets, and what is known regarding the impact of polyQ expansion on ataxin-3's DUB function. We also consider the potential neuroprotective effects of ataxin-3's DUB function, and the intersection of ataxin-3's role as a DUB enzyme and regulator of gene transcription. Ataxin-3 is the principal pathogenic protein in MJD and also appears to be involved in cancer. As aberrant deubiquitination has been linked to both neurodegeneration and cancer, a comprehensive understanding of ataxin-3's DUB function is important for elucidating potential therapeutic targets in these complex conditions. In this review, we aim to consolidate knowledge of ataxin-3 as a DUB and unveil areas for future research to aid therapeutic targeting of ataxin-3's DUB function for the treatment of MJD and other diseases.
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Affiliation(s)
- Anastasiya Potapenko
- Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Jennilee M. Davidson
- Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Albert Lee
- Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Angela S. Laird
- Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
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2
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Li Z, Zhao J, Wu Y, Fan S, Yuan H, Xia J, Hu L, Yang J, Liu J, Wu X, Lin R, Yang L. TRAF2 decrease promotes the TGF-β-mTORC1 signal in MAFLD-HCC through enhancing AXIN1-mediated Smad7 degradation. FASEB J 2024; 38:e23491. [PMID: 38363556 DOI: 10.1096/fj.202302307r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/13/2024] [Accepted: 02/01/2024] [Indexed: 02/17/2024]
Abstract
According to recent research, metabolic-associated fatty liver disease (MAFLD) has emerged as an important underlying etiology of hepatocellular carcinoma (HCC). However, the molecular mechanism of MAFLD-HCC is still unclear. Tumor necrosis factor receptor-associated factor 2 (TRAF2) is the key molecule to mediate the signal of inflammatory NF-κB pathway. This study aims to investigate the potential dysregulation of TRAF2 and its biological function in MAFLD-HCC. Huh7 TRAF2-/- demonstrated increased tumor formation ability compared to huh7 TRAF2+/+ when stimulated with transforming growth factor-β (TGF-β). The decisive role of TGF-β in the development of MAFLD-HCC was confirmed through the specific depletion of TGF-β receptor II gene in the hepatocytes (Tgfbr2ΔHep) of mice. In TRAF2-/- cells treated with TGF-β, both the glycolysis rate and lipid synthesis were enhanced. We proved the signal of the mechanistic target of rapamycin complex 1 (mTORC1) could be activated in the presence of TGF-β, and was enhanced in TRAF2-/- cells. The coimmunoprecipitation (co-IP) experiments revealed that TRAF2 fortified the Smurf2-mediated ubiquitination degradation of AXIN1. Hence, TRAF2 depletion resulted in increased Smad7 degradation induced by AXIN1, thus promoting the TGF-β signal. We also discovered that PLX-4720 could bind with AXIN1 and restrained the tumor proliferation of TRAF2-/- in mice fed with high-fat diet (HFD). Our findings indicate that TRAF2 plays a significant role in the pathogenesis of MAFLD-HCC. The reduction of TRAF2 expression leads to the enhancement of the TGF-β-mTORC1 pathway by facilitating AXIN1-mediated Smad7 degradation.
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Affiliation(s)
- Zhonglin Li
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinfang Zhao
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya Wu
- Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Siyuan Fan
- Cardiovascular Medicine Department, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hang Yuan
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Xia
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lilin Hu
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jingze Yang
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiazheng Liu
- State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau, China
| | - Xuefeng Wu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Rong Lin
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ling Yang
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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3
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Xia D, Zhu X, Wang Y, Gong P, Su HS, Xu X. Implications of ubiquitination and the maintenance of replication fork stability in cancer therapy. Biosci Rep 2023; 43:BSR20222591. [PMID: 37728310 PMCID: PMC10550789 DOI: 10.1042/bsr20222591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 08/21/2023] [Accepted: 09/19/2023] [Indexed: 09/21/2023] Open
Abstract
DNA replication forks are subject to intricate surveillance and strict regulation by sophisticated cellular machinery. Such close regulation is necessary to ensure the accurate duplication of genetic information and to tackle the diverse endogenous and exogenous stresses that impede this process. Stalled replication forks are vulnerable to collapse, which is a major cause of genomic instability and carcinogenesis. Replication stress responses, which are organized via a series of coordinated molecular events, stabilize stalled replication forks and carry out fork reversal and restoration. DNA damage tolerance and repair pathways such as homologous recombination and Fanconi anemia also contribute to replication fork stabilization. The signaling network that mediates the transduction and interplay of these pathways is regulated by a series of post-translational modifications, including ubiquitination, which affects the activity, stability, and interactome of substrates. In particular, the ubiquitination of replication protein A and proliferating cell nuclear antigen at stalled replication forks promotes the recruitment of downstream regulators. In this review, we describe the ubiquitination-mediated signaling cascades that regulate replication fork progression and stabilization. In addition, we discuss the targeting of replication fork stability and ubiquitination system components as a potential therapeutic approach for the treatment of cancer.
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Affiliation(s)
- Donghui Xia
- Shenzhen University General Hospital-Dehua Hospital Joint Research Center on Precision Medicine (sgh-dhhCPM), Dehua Hospital, Dehua, Quanzhou 362500, China
- Guangdong Key Laboratory for Genome Stability and Disease Prevention, Carson International Cancer Center, Marshall Laboratory of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong 518060, China
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xuefei Zhu
- Department of General Surgery, Institute of Precision Diagnosis and Treatment of Gastrointestinal Tumors and Carson International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Ying Wang
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Peng Gong
- Department of General Surgery, Institute of Precision Diagnosis and Treatment of Gastrointestinal Tumors and Carson International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Hong-Shu Su
- Shenzhen University General Hospital-Dehua Hospital Joint Research Center on Precision Medicine (sgh-dhhCPM), Dehua Hospital, Dehua, Quanzhou 362500, China
| | - Xingzhi Xu
- Shenzhen University General Hospital-Dehua Hospital Joint Research Center on Precision Medicine (sgh-dhhCPM), Dehua Hospital, Dehua, Quanzhou 362500, China
- Guangdong Key Laboratory for Genome Stability and Disease Prevention, Carson International Cancer Center, Marshall Laboratory of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong 518060, China
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Wang X, Zhang X, Song CP, Gong Z, Yang S, Ding Y. PUB25 and PUB26 dynamically modulate ICE1 stability via differential ubiquitination during cold stress in Arabidopsis. THE PLANT CELL 2023; 35:3585-3603. [PMID: 37279565 PMCID: PMC10473228 DOI: 10.1093/plcell/koad159] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 05/09/2023] [Accepted: 05/19/2023] [Indexed: 06/08/2023]
Abstract
Ubiquitination modulates protein turnover or activity depending on the number and location of attached ubiquitin (Ub) moieties. Proteins marked by a lysine 48 (K48)-linked polyubiquitin chain are usually targeted to the 26S proteasome for degradation; however, other polyubiquitin chains, such as those attached to K63, usually regulate other protein properties. Here, we show that 2 PLANT U-BOX E3 ligases, PUB25 and PUB26, facilitate both K48- and K63-linked ubiquitination of the transcriptional regulator INDUCER OF C-REPEAT BINDING FACTOR (CBF) EXPRESSION1 (ICE1) during different periods of cold stress in Arabidopsis (Arabidopsis thaliana), thus dynamically modulating ICE1 stability. Moreover, PUB25 and PUB26 attach both K48- and K63-linked Ub chains to MYB15 in response to cold stress. However, the ubiquitination patterns of ICE1 and MYB15 mediated by PUB25 and PUB26 differ, thus modulating their protein stability and abundance during different stages of cold stress. Furthermore, ICE1 interacts with and inhibits the DNA-binding activity of MYB15, resulting in an upregulation of CBF expression. This study unravels a mechanism by which PUB25 and PUB26 add different polyubiquitin chains to ICE1 and MYB15 to modulate their stability, thereby regulating the timing and degree of cold stress responses in plants.
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Affiliation(s)
- Xi Wang
- State Key Laboratory of Plant Environmental Resilience, Frontiers Science Center for Molecular Design Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaoyan Zhang
- State Key Laboratory of Plant Environmental Resilience, Frontiers Science Center for Molecular Design Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Chun-Peng Song
- Institute of Plant Stress Biology, Collaborative Innovation Center of Crop Stress Biology, Henan University, Kaifeng 475004, China
| | - Zhizhong Gong
- State Key Laboratory of Plant Environmental Resilience, Frontiers Science Center for Molecular Design Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding 071002, China
| | - Shuhua Yang
- State Key Laboratory of Plant Environmental Resilience, Frontiers Science Center for Molecular Design Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yanglin Ding
- State Key Laboratory of Plant Environmental Resilience, Frontiers Science Center for Molecular Design Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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Liu J, Nie B, Yu B, Xu F, Zhang Q, Wang Y, Xu W. Rice ubiquitin-conjugating enzyme OsUbc13 negatively regulates immunity against pathogens by enhancing the activity of OsSnRK1a. PLANT BIOTECHNOLOGY JOURNAL 2023. [PMID: 37102249 PMCID: PMC10363768 DOI: 10.1111/pbi.14059] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 02/28/2023] [Accepted: 04/05/2023] [Indexed: 06/19/2023]
Abstract
Ubc13 is required for Lys63-linked polyubiquitination and innate immune responses in mammals, but its functions in plant immunity still remain largely unknown. Here, we used molecular biological, pathological, biochemical, and genetic approaches to evaluate the roles of rice OsUbc13 in response to pathogens. The OsUbc13-RNA interference (RNAi) lines with lesion mimic phenotypes displayed a significant increase in the accumulation of flg22- and chitin-induced reactive oxygen species, and in defence-related genes expression or hormones as well as resistance to Magnaporthe oryzae and Xanthomonas oryzae pv oryzae. Strikingly, OsUbc13 directly interacts with OsSnRK1a, which is the α catalytic subunit of SnRK1 (sucrose non-fermenting-1-related protein kinase-1) and acts as a positive regulator of broad-spectrum disease resistance in rice. In the OsUbc13-RNAi plants, although the protein level of OsSnRK1a did not change, its activity and ABA sensitivity were obviously enhanced, and the K63-linked polyubiquitination was weaker than that of wild-type Dongjin (DJ). Overexpression of the deubiquitinase-encoding gene OsOTUB1.1 produced similar effects with inhibition of OsUbc13 in affecting immunity responses, M. oryzae resistance, OsSnRK1a ubiquitination, and OsSnRK1a activity. Furthermore, re-interfering with OsSnRK1a in one OsUbc13-RNAi line (Ri-3) partially restored its M. oryzae resistance to a level between those of Ri-3 and DJ. Our data demonstrate OsUbc13 negatively regulates immunity against pathogens by enhancing the activity of OsSnRK1a.
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Affiliation(s)
- Jianping Liu
- Center for Plant Water-use and Nutrition Regulation and College of Resources and Environment, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Bo Nie
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Boling Yu
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Feiyun Xu
- Center for Plant Water-use and Nutrition Regulation and College of Resources and Environment, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qian Zhang
- Center for Plant Water-use and Nutrition Regulation and College of Resources and Environment, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ya Wang
- Cereal Crops Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Weifeng Xu
- Center for Plant Water-use and Nutrition Regulation and College of Resources and Environment, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, China
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6
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McGoldrick P, Lau A, You Z, Durcan TM, Robertson J. Loss of C9orf72 perturbs the Ran-GTPase gradient and nucleocytoplasmic transport, generating compositionally diverse Importin β-1 granules. Cell Rep 2023; 42:112134. [PMID: 36821445 DOI: 10.1016/j.celrep.2023.112134] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/05/2022] [Accepted: 01/31/2023] [Indexed: 02/24/2023] Open
Abstract
A hexanucleotide (GGGGCC)n repeat expansion in C9orf72 causes amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), eliciting toxic effects through generation of RNA foci, dipeptide repeat proteins, and/or loss of C9orf72 protein. Defects in nucleocytoplasmic transport (NCT) have been implicated as a pathogenic mechanism underlying repeat expansion toxicity. Here, we show that loss of C9orf72 disrupts the Ran-GTPase gradient and NCT in vitro and in vivo. NCT disruption in vivo is enhanced by the presence of compositionally different types of cytoplasmic Importin β-1 granule that exhibit neuronal subtype-specific properties. We show that the abundance of Importin β-1 granules is increased in the context of C9orf72 deficiency, disrupting interactions with nuclear pore complex proteins. These granules appear to associate with the nuclear envelope and are co-immunoreactive for G3BP1 and K63-ubiquitin. These findings link loss of C9orf72 protein to gain-of-function mechanisms and defects in NCT.
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Affiliation(s)
- Philip McGoldrick
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada.
| | - Agnes Lau
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada
| | - Zhipeng You
- The Neuro's Early Drug Discovery Unit (EDDU), McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Thomas M Durcan
- The Neuro's Early Drug Discovery Unit (EDDU), McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Janice Robertson
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada; Department of Laboratory Medicine and Pathobiology, 27 King's College Circle, Toronto, ON M5S 1A1, Canada.
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7
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Bhat SA, Vasi Z, Adhikari R, Gudur A, Ali A, Jiang L, Ferguson R, Liang D, Kuchay S. Ubiquitin proteasome system in immune regulation and therapeutics. Curr Opin Pharmacol 2022; 67:102310. [PMID: 36288660 PMCID: PMC10163937 DOI: 10.1016/j.coph.2022.102310] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 08/03/2022] [Accepted: 09/20/2022] [Indexed: 01/25/2023]
Abstract
The ubiquitin proteasome system (UPS) is a proteolytic machinery for the degradation of protein substrates that are post-translationally conjugated with ubiquitin polymers through the enzymatic action of ubiquitin ligases, in a process termed ubiquitylation. Ubiquitylation of substrates precedes their proteolysis via proteasomes, a hierarchical feature of UPS. E3-ubiquitin ligases recruit protein substrates providing specificity for ubiquitylation. Innate and adaptive immune system networks are regulated by ubiquitylation and substrate degradation via E3-ligases/UPS. Deregulation of E3-ligases/UPS components in immune cells is involved in the development of lymphomas, neurodevelopmental abnormalities, and cancers. Targeting E3-ligases for therapeutic intervention provides opportunities to mitigate the unintended broad effects of 26S proteasome inhibition. Recently, bifunctional moieties such as PROTACs and molecular glues have been developed to re-purpose E3-ligases for targeted degradation of unwanted aberrant proteins, with a potential for clinical use. Here, we summarize the involvement of E3-ligases/UPS components in immune-related diseases with perspectives.
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Affiliation(s)
- Sameer Ahmed Bhat
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - Zahra Vasi
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - Ritika Adhikari
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - Anish Gudur
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - Asceal Ali
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - Liping Jiang
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - Rachel Ferguson
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - David Liang
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA
| | - Shafi Kuchay
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago (UIC), Chicago, IL, 60607, USA.
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Tiwari S, Singh A, Gupta P, Singh S. UBA52 Is Crucial in HSP90 Ubiquitylation and Neurodegenerative Signaling during Early Phase of Parkinson's Disease. Cells 2022; 11:cells11233770. [PMID: 36497031 PMCID: PMC9738938 DOI: 10.3390/cells11233770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/29/2022] Open
Abstract
Protein aggregation is one of the major pathological events in age-related Parkinson's disease (PD) pathology, predominantly regulated by the ubiquitin-proteasome system (UPS). UPS essentially requires core component ubiquitin; however, its role in PD pathology is obscure. This study aimed to investigate the role of ubiquitin-encoding genes in sporadic PD pathology. Both cellular and rat models of PD as well as SNCA C57BL/6J-Tg (Th-SNCA*A30P*A53T)39 Eric/J transgenic mice showed a decreased abundance of UBA52 in conjunction with significant downregulation of tyrosine hydroxylase (TH) and neuronal death. In silico predictions, mass spectrometric analysis, and co-immunoprecipitation findings suggested the protein-protein interaction of UBA52 with α-synuclein, HSP90 and E3-ubiquitin ligase CHIP, and its co-localization with α-synuclein in the mitochondrion. Next, in vitro ubiquitylation assay indicated an imperative requirement of the lysine-63 residue of UBA52 in CHIP-mediated HSP90 ubiquitylation. Myc-UBA52 expressed neurons inhibited alteration in PD-specific markers such as α-synuclein and TH protein along with increased proteasome activity in diseased conditions. Furthermore, Myc-UBA52 expression inhibited the altered protein abundance of HSP90 and its various client proteins, HSP75 (homolog of HSP90 in mitochondrion) and ER stress-related markers during early PD. Taken together, the data highlights the critical role of UBA52 in HSP90 ubiquitylation in parallel to its potential contribution to the modulation of various disease-related neurodegenerative signaling targets during the early phase of PD pathology.
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Affiliation(s)
- Shubhangini Tiwari
- Division of Toxicology and Experimental Medicine, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Abhishek Singh
- Division of Toxicology and Experimental Medicine, CSIR-Central Drug Research Institute, Lucknow 226031, India
- Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Parul Gupta
- Division of Toxicology and Experimental Medicine, CSIR-Central Drug Research Institute, Lucknow 226031, India
- Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sarika Singh
- Division of Toxicology and Experimental Medicine, CSIR-Central Drug Research Institute, Lucknow 226031, India
- Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, India
- Correspondence:
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9
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The role of K63-linked polyubiquitin in several types of autophagy. Biol Futur 2022; 73:137-148. [DOI: 10.1007/s42977-022-00117-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 04/05/2022] [Indexed: 01/08/2023]
Abstract
AbstractLysosomal-dependent self-degradative (autophagic) mechanisms are essential for the maintenance of normal homeostasis in all eukaryotic cells. Several types of such self-degradative and recycling pathways have been identified, based on how the cellular self material can incorporate into the lysosomal lumen. Ubiquitination, a well-known and frequently occurred posttranslational modification has essential role in all cell biological processes, thus in autophagy too. The second most common type of polyubiquitin chain is the K63-linked polyubiquitin, which strongly connects to some self-degradative mechanisms in the cells. In this review, we discuss the role of this type of polyubiquitin pattern in numerous autophagic processes.
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10
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Sun R, Guo Y, Li X, Li R, Shi J, Tan Z, Zhang L, Zhang L, Han J, Huang J. PRRSV Non-Structural Proteins Orchestrate Porcine E3 Ubiquitin Ligase RNF122 to Promote PRRSV Proliferation. Viruses 2022; 14:v14020424. [PMID: 35216017 PMCID: PMC8874583 DOI: 10.3390/v14020424] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/09/2022] [Accepted: 02/15/2022] [Indexed: 02/04/2023] Open
Abstract
Ubiquitination plays a major role in immune regulation after viral infection. An alternatively spliced porcine E3 ubiquitin ligase RNF122 promoted PRRSV infection and upregulated in PRRSV-infected PAM cells was identified. We characterized the core promoter of RNF122, located between −550 to −470 bp upstream of the transcription start site (TSS), which displayed significant differential transcriptional activities in regulating the transcription and expression of RNF122. The transcription factor HLTF was inhibited by nsp1α and nsp7 of PRRSV, and the transcription factor E2F complex regulated by nsp9. Together, they modulated the transcription and expression of RNF122. RNF122 could mediate K63-linked ubiquitination to raise stability of PRRSV nsp4 protein and thus promote virus replication. Moreover, RNF122 also performed K27-linked and K48-linked ubiquitination of MDA5 to degrade MDA5 and inhibit IFN production, ultimately promoted virus proliferation. In this study, we illustrate a new immune escape mechanism of PRRSV that enhances self-stability and function of viral nsp4, thus, regulating RNF122 expression to antagonize IFNα/β production. The present study broadens our knowledge of PRRSV-coding protein modulating transcription, expression and modification of host protein to counteract innate immune signaling, and may provide novel insights for the development of antiviral drugs.
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Affiliation(s)
- Ruiqi Sun
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Yanyu Guo
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Xiaoyang Li
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Ruiqiao Li
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Jingxuan Shi
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Zheng Tan
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Lilin Zhang
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Lei Zhang
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
| | - Jun Han
- College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Correspondence: (J.H.); (J.H.)
| | - Jinhai Huang
- School of Life Sciences, Tianjin University, Tianjin 300072, China; (R.S.); (Y.G.); (X.L.); (R.L.); (J.S.); (Z.T.); (L.Z.); (L.Z.)
- Correspondence: (J.H.); (J.H.)
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11
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Li Y, Yang C, Wang H, Zhao L, Kong Q, Cang Y, Zhao S, Lv L, Li Y, Mao B, Ma P. Sequential stabilization of RNF220 by RLIM and ZC4H2 during cerebellum development and Shh-group medulloblastoma progression. J Mol Cell Biol 2022; 14:6510822. [PMID: 35040952 PMCID: PMC8982406 DOI: 10.1093/jmcb/mjab082] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/12/2021] [Accepted: 12/30/2021] [Indexed: 11/21/2022] Open
Abstract
Sonic hedgehog (Shh) signaling is essential for the proliferation of cerebellar granule neuron progenitors (CGNPs), and its misregulation is linked to various disorders, including cerebellar cancer medulloblastoma (MB). During vertebrate neural development, RNF220, a ubiquitin E3 ligase, is involved in spinal cord patterning by modulating the subcellular location of glioma-associated oncogene homologs (Glis) through ubiquitination. RNF220 is also required for full activation of Shh signaling during cerebellum development in an epigenetic manner through targeting embryonic ectoderm development. ZC4H2 was reported to be involved in spinal cord patterning by acting as an RNF220 stabilizer. Here, we provided evidence to show that ZC4H2 is also required for full activation of Shh signaling in CGNP and MB progression by stabilizing RNF220. In addition, we found that the ubiquitin E3 ligase RING finger LIM domain-binding protein (RLIM) is responsible for ZC4H2 stabilization via direct ubiquitination, through which RNF220 is also thus stabilized. RLIM is a direct target of Shh signaling and is also required for full activation of Shh signaling in CGNP and MB cell proliferation. We further provided clinical evidence to show that the RLIM‒ZC4H2‒RNF220 cascade is involved in Shh-group MB progression. Disease-causative human RLIM and ZC4H2 mutations affect their interaction and regulation. Therefore, our study sheds light on the regulation of Shh signaling during cerebellar development and MB progression and provides insights into neural disorders caused by RLIM or ZC4H2 mutations.
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Affiliation(s)
- Yuwei Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650203, China
| | - Chencheng Yang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650203, China
| | - Huishan Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650203, China
| | - Ling Zhao
- Experimental Animal Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Qinghua Kong
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650223, China
| | - Yu Cang
- Department of Urology, the Affiliated Hospital of Yunnan University, Kunming 650021, China
| | - Shuhua Zhao
- First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
| | - Longbao Lv
- Experimental Animal Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Yan Li
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650223, China
| | - Bingyu Mao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Pengcheng Ma
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
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12
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Dong L, Liu L, Li Y, Li W, Zhou L, Xia Q. E3 ligase Smurf1 protects against misfolded SOD1 in neuronal cells by promoting its K63 ubiquitylation and aggresome formation. Hum Mol Genet 2022; 31:2035-2048. [PMID: 35022748 DOI: 10.1093/hmg/ddac008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/15/2021] [Accepted: 01/07/2022] [Indexed: 11/15/2022] Open
Abstract
K63-linked polyubiquitination of the neurodegenerative disease-associated misfolded protein copper-zinc superoxide dismutase (SOD1) is associated with the formation of inclusion bodies. Highly expressed E3 ligase Smurf1 promotes cellular homostasis through the enhanced capability of aggregate degradation. However, it is not well explored the role of Smurf1 in the dynamics of SOD1 aggresomes. In this study, we report that Smurf1 promotes the recruitment of SOD1 to form aggresomes. Mechanistically, Smurf1 interacts with mutant SOD1 to promote aggresome formation by modification of its K63-linked polyubiquitination. Moreover, overexpressed Smurf1 enhances mutant SOD1 aggresome formation and autophagic degradation to prevent cell death. Thus, our data suggest that Smurf1 plays an important role in attenuating protein misfolding-induced cell toxicity by both driving the sequestration of misfolded SOD1 into aggresomes and autophagic degradation.
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Affiliation(s)
- Lei Dong
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Liqun Liu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Yang Li
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Wenxuan Li
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Liying Zhou
- Beijing Tide Pharmaceutical CO., LTD, Beijing, 100000, China
| | - Qin Xia
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
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13
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Cai M, Ding J, Li Y, He G, Yang J, Liu T, Guo X, Yang X, Wang X, Cho WC, Fasihi Harandi M, Zheng Y. Echinococcus multilocularis infection induces UBE2N suppression via exosomal emu-miR-4989. Acta Trop 2021; 223:106087. [PMID: 34389329 DOI: 10.1016/j.actatropica.2021.106087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/23/2021] [Accepted: 08/04/2021] [Indexed: 11/22/2022]
Abstract
Echinococcus multilocularis metacestodes mainly reside in liver in humans and animals, and cause serious damages. UBE2N was herein shown to be downregulated in response to the infection. UBE2N was further shown to be predominantly expressed in the hepatocytes, which was also significantly downregulated during the infection. UBE2N was a target of emu-miR-4989, which was loaded into the exosomes secreted by parasites. These emu-miR-4989-encapsulating exosomes were internalized by hepatocytes, and induced a significant decrease of relative luciferase activity in the cells transfected with the construct containing a wild type of UBE2N 3'-UTR compared to the control (p < 0.05). These results demonstrate that emu-miR-4989 is involved in the UBE2N inhibition in the hepatocytes during E. multilocularis through exosomes.
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Affiliation(s)
- Mengting Cai
- College of Life Science and Technology, Xinjiang University, Urumqi, China; State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China
| | - Juntao Ding
- College of Life Science and Technology, Xinjiang University, Urumqi, China
| | - Yating Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China
| | - Guitian He
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China
| | - Jing Yang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China
| | - Tingli Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China
| | - Xiaola Guo
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China
| | - Xing Yang
- Department of Medical Microbiology and Immunology, School of Basic Medicine, Dali University, Dali 671000, Yunnan, China
| | - Xiaoqiang Wang
- School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - William C Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong SAR, China
| | - Majid Fasihi Harandi
- Research Center for Hydatid Disease in Iran, Department of Parasitology, Kerman University of Medical Sciences, Kerman, Iran
| | - Yadong Zheng
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
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14
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Nuro-Gyina PK, Tang N, Guo H, Yan C, Zeng Q, Waldschmidt TJ, Zhang J. HECT E3 Ubiquitin Ligase Nedd4 Is Required for Antifungal Innate Immunity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2021; 207:868-877. [PMID: 34282001 PMCID: PMC8324540 DOI: 10.4049/jimmunol.2100083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/19/2021] [Indexed: 11/19/2022]
Abstract
Candida albicans is the most common cause of fungal infections in humans, and disseminated candidiasis has become one of the leading causes of hospital-acquired bloodstream infections with a high mortality rate. However, little is known about the host-pathogen interactions and the mechanisms of antifungal immunity. Here, we report that Nedd4 (neuronal precursor cell-expressed developmentally downregulated 4) is essential for signaling through Dectin-1 and Dectin-2/3. We showed that mice that lack Nedd4 globally or only in the myeloid compartment are highly susceptible to systemic C. albicans infection, which correlates with heightened organ fungal burden, defective inflammatory response, impaired leukocyte recruitment to the kidneys, and defective reactive oxygen species expression by granulocytes. At the molecular level, Nedd4 -/- macrophages displayed impaired activation of TGF-β-activating kinase-1 and NF-κB, but normal activation of spleen tyrosine kinase and protein kinase C-δ on C. albicans yeast and hyphal infections. These data suggest that Nedd4 regulates signaling events downstream of protein kinase C-δ but upstream of or at TGF-β-activating kinase-1.
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Affiliation(s)
- Patrick K Nuro-Gyina
- Biomedical Science Graduate Program, Ohio State University, Columbus, OH; and
- Department of Pathology, University of Iowa, Iowa City, IA
| | - Na Tang
- Department of Pathology, University of Iowa, Iowa City, IA
| | - Hui Guo
- Department of Pathology, University of Iowa, Iowa City, IA
| | - Chengkai Yan
- Department of Pathology, University of Iowa, Iowa City, IA
| | - Qiuming Zeng
- Department of Pathology, University of Iowa, Iowa City, IA
| | | | - Jian Zhang
- Biomedical Science Graduate Program, Ohio State University, Columbus, OH; and
- Department of Pathology, University of Iowa, Iowa City, IA
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15
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Li S, Guo W, Wu H. The role of post-translational modifications in the regulation of MCL1. Cell Signal 2021; 81:109933. [PMID: 33508399 DOI: 10.1016/j.cellsig.2021.109933] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 12/25/2022]
Abstract
Apoptosis is an evolutionarily conserved form of programed cell death (PCD) that has a vital effect on early embryonic development, tissue homeostasis and clearance of damaged cells. Dysregulation of apoptosis can lead to many diseases, such as Alzheimer's disease, cancer, AIDS and heart disease. The anti-apoptotic protein MCL1, a member of the BCL2 family, plays important roles in these physiological and pathological processes. Its high expression is closely related to drug resistances in the treatment of tumor. This review summarizes the structure and function of MCL1, the types of post-translational modifications of MCL1 and their effects on the functions of MCL1, as well as the treatment strategies targeting MCL1 in cancer therapy. The research on the fine regulation of MCL1 will be favorable to the provision of a promising future for the design and screening of MCL1 inhibitors.
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Affiliation(s)
- Shujing Li
- School of Bioengineering & Province Key Laboratory of Protein Modification and Disease, Liaoning Province, Dalian University of Technology, China
| | - Wanping Guo
- School of Bioengineering & Province Key Laboratory of Protein Modification and Disease, Liaoning Province, Dalian University of Technology, China
| | - Huijian Wu
- School of Bioengineering & Province Key Laboratory of Protein Modification and Disease, Liaoning Province, Dalian University of Technology, China.
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16
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Remodeling without destruction: non-proteolytic ubiquitin chains in neural function and brain disorders. Mol Psychiatry 2021; 26:247-264. [PMID: 32709994 PMCID: PMC9229342 DOI: 10.1038/s41380-020-0849-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 07/08/2020] [Accepted: 07/14/2020] [Indexed: 12/31/2022]
Abstract
Ubiquitination is a fundamental posttranslational protein modification that regulates diverse biological processes, including those in the CNS. Several topologically and functionally distinct polyubiquitin chains can be assembled on protein substrates, modifying their fates. The classical and most prevalent polyubiquitin chains are those that tag a substrate to the proteasome for degradation, which has been established as a major mechanism driving neural circuit deconstruction and remodeling. In contrast, proteasome-independent non-proteolytic polyubiquitin chains regulate protein scaffolding, signaling complex formation, and kinase activation, and play essential roles in an array of signal transduction processes. Despite being a cornerstone in immune signaling and abundant in the mammalian brain, these non-proteolytic chains are underappreciated in neurons and synapses in the brain. Emerging studies have begun to generate exciting insights about some fundamental roles played by these non-degradative chains in neuronal function and plasticity. In addition, their roles in a number of brain diseases are being recognized. In this article, we discuss recent advances on these nonconventional ubiquitin chains in neural development, function, plasticity, and related pathologies.
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17
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Kelley AR, Bach SB, Perry G. Analysis of post-translational modifications in Alzheimer's disease by mass spectrometry. Biochim Biophys Acta Mol Basis Dis 2019; 1865:2040-2047. [DOI: 10.1016/j.bbadis.2018.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/19/2018] [Accepted: 11/04/2018] [Indexed: 01/09/2023]
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18
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Seenivasan R, Hermanns T, Blyszcz T, Lammers M, Praefcke GJK, Hofmann K. Mechanism and chain specificity of RNF216/TRIAD3, the ubiquitin ligase mutated in Gordon Holmes syndrome. Hum Mol Genet 2019; 28:2862-2873. [DOI: 10.1093/hmg/ddz098] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/26/2019] [Accepted: 05/07/2019] [Indexed: 12/18/2022] Open
Abstract
AbstractGordon Holmes syndrome (GDHS) is an adult-onset neurodegenerative disorder characterized by ataxia and hypogonadotropic hypogonadism. GDHS is caused by mutations in the gene encoding the RING-between-RING (RBR)-type ubiquitin ligase RNF216, also known as TRIAD3. The molecular pathology of GDHS is not understood, although RNF216 has been reported to modify several substrates with K48-linked ubiquitin chains, thereby targeting them for proteasomal degradation. We identified RNF216 in a bioinformatical screen for putative SUMO-targeted ubiquitin ligases and confirmed that a cluster of predicted SUMO-interaction motifs (SIMs) indeed recognizes SUMO2 chains without targeting them for ubiquitination. Surprisingly, purified RNF216 turned out to be a highly active ubiquitin ligase that exclusively forms K63-linked ubiquitin chains, suggesting that the previously reported increase of K48-linked chains after RNF216 overexpression is an indirect effect. The linkage-determining region of RNF216 was mapped to a narrow window encompassing the last two Zn-fingers of the RBR triad, including a short C-terminal extension. Neither the SIMs nor a newly discovered ubiquitin-binding domain in the central portion of RNF216 contributes to chain specificity. Both missense mutations reported in GDHS patients completely abrogate the ubiquitin ligase activity. For the R660C mutation, ligase activity could be restored by using a chemical ubiquitin loading protocol that circumvents the requirement for ubiquitin-conjugating (E2) enzymes. This result suggests Arg-660 to be required for the ubiquitin transfer from the E2 to the catalytic cysteine. Our findings necessitate a re-evaluation of the previously assumed degradative role of RNF216 and rather argue for a non-degradative K63 ubiquitination, potentially acting on SUMOylated substrates.
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Affiliation(s)
- Ramkumar Seenivasan
- Institute for Genetics, University of Cologne, Zülpicher Str. 47a, 50674 Cologne, Germany
| | - Thomas Hermanns
- Institute for Genetics, University of Cologne, Zülpicher Str. 47a, 50674 Cologne, Germany
| | - Tamara Blyszcz
- Institute for Genetics, University of Cologne, Zülpicher Str. 47a, 50674 Cologne, Germany
| | - Michael Lammers
- Institute for Genetics, University of Cologne, Zülpicher Str. 47a, 50674 Cologne, Germany
- Institute of Biochemistry, Synthetic and Structural Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Gerrit J K Praefcke
- Institute for Genetics, University of Cologne, Zülpicher Str. 47a, 50674 Cologne, Germany
- Division of Haematology and Transfusion Medicine, Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, 63225 Langen, Germany
| | - Kay Hofmann
- Institute for Genetics, University of Cologne, Zülpicher Str. 47a, 50674 Cologne, Germany
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19
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Kim S, Zhang Y, Jin C, Lee Y, Kim Y, Han K. Emerging roles of Lys63-linked polyubiquitination in neuronal excitatory postsynapses. Arch Pharm Res 2018; 42:285-292. [DOI: 10.1007/s12272-018-1081-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 09/21/2018] [Indexed: 10/28/2022]
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20
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Yan K, Ponnusamy M, Xin Y, Wang Q, Li P, Wang K. The role of K63-linked polyubiquitination in cardiac hypertrophy. J Cell Mol Med 2018; 22:4558-4567. [PMID: 30102008 PMCID: PMC6156430 DOI: 10.1111/jcmm.13669] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/20/2018] [Indexed: 12/26/2022] Open
Abstract
Ubiquitination, also known as ubiquitylation, is a vital post‐translational modification of proteins that play a crucial role in the multiple biological processes including cell growth, proliferation and apoptosis. K63‐linked ubiquitination is one of the vital post‐translational modifications of proteins that are involved in the activation of protein kinases and protein trafficking during cell survival and proliferation. It also contributes to the development of various disorders including cancer, neurodegeneration and cardiac hypertrophy. In this review, we summarize the role of K63‐linked ubiquitination signalling in protein kinase activation and its implications in cardiac hypertrophy. We have also provided our perspectives on therapeutically targeting K63‐linked ubiquitination in downstream effector molecules of growth factor receptors for the treatment of cardiac hypertrophy.
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Affiliation(s)
- Kaowen Yan
- Institute for Translational Medicine, Qingdao University, Qingdao, China
| | | | - Ying Xin
- The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Qi Wang
- Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Kun Wang
- Institute for Translational Medicine, Qingdao University, Qingdao, China
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21
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Shi WN, Cui SX, Song ZY, Wang SQ, Sun SY, Yu XF, Li Y, Zhang YH, Gao ZH, Qu XJ. Overexpression of SphK2 contributes to ATRA resistance in colon cancer through rapid degradation of cytoplasmic RXRα by K48/K63-linked polyubiquitination. Oncotarget 2018; 8:39605-39617. [PMID: 28465486 PMCID: PMC5503636 DOI: 10.18632/oncotarget.17174] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/26/2017] [Indexed: 12/27/2022] Open
Abstract
The resistance mechanisms that limit the efficacy of retinoid therapy in cancer are poorly understood. Sphingosine kinase 2 (SphK2) is a highly conserved enzyme that is mainly located in the nucleus and endoplasmic reticulum. Unlike well-studied sphingosine kinase 1 (SphK1) located in the cytosol, little has yet understood the functions of SphK2. Here we show that SphK2 overexpression contributes to the resistance of all-trans retinoic acid (ATRA) therapy in colon cancer through rapid degradation of cytoplasmic retinoid X receptor α (RXRα) by lysine 48 (K48)- and lysine 63 (K63)-based polyubiquitination. Human colonic adenocarcinoma HCT-116 cells transfected with SphK2 (HCT-116Sphk2 cells) demonstrate resistance to ATRA therapy as determined by in vitro and in vivo assays. Sphk2 overexpression increases the ATRA-induced nuclear RXRα export to cytoplasm and then rapidly degrades RXRα through the polyubiquitination pathway. We further show that Sphk2 activates the ubiquitin-proteasome system through the signal mechanisms of (1) K48-linked proteosomal degradation and (2) K63-linked ubiquitin-dependent autophagic degradation. These results provide new insights into the biological functions of Sphk2 and the molecular mechanisms that underlie the Sphk2-mediated resistance to retinoid therapy.
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Affiliation(s)
- Wen-Na Shi
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Shu-Xiang Cui
- Beijing Key Laboratory of Environmental Toxicology, Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing, China
| | - Zhi-Yu Song
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Shu-Qing Wang
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Shi-Yue Sun
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xin-Feng Yu
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Ye Li
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yu-Hang Zhang
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Zu-Hua Gao
- Department of Pathology, McGill University, Montreal, Quebec, Canada
| | - Xian-Jun Qu
- Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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22
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Gray KM, Kaifer KA, Baillat D, Wen Y, Bonacci TR, Ebert AD, Raimer AC, Spring AM, Have ST, Glascock JJ, Gupta K, Van Duyne GD, Emanuele MJ, Lamond AI, Wagner EJ, Lorson CL, Matera AG. Self-oligomerization regulates stability of survival motor neuron protein isoforms by sequestering an SCF Slmb degron. Mol Biol Cell 2018; 29:96-110. [PMID: 29167380 PMCID: PMC5909936 DOI: 10.1091/mbc.e17-11-0627] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/14/2017] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous mutations in human SMN1 Expression of a duplicate gene (SMN2) primarily results in skipping of exon 7 and production of an unstable protein isoform, SMNΔ7. Although SMN2 exon skipping is the principal contributor to SMA severity, mechanisms governing stability of survival motor neuron (SMN) isoforms are poorly understood. We used a Drosophila model system and label-free proteomics to identify the SCFSlmb ubiquitin E3 ligase complex as a novel SMN binding partner. SCFSlmb interacts with a phosphor degron embedded within the human and fruitfly SMN YG-box oligomerization domains. Substitution of a conserved serine (S270A) interferes with SCFSlmb binding and stabilizes SMNΔ7. SMA-causing missense mutations that block multimerization of full-length SMN are also stabilized in the degron mutant background. Overexpression of SMNΔ7S270A, but not wild-type (WT) SMNΔ7, provides a protective effect in SMA model mice and human motor neuron cell culture systems. Our findings support a model wherein the degron is exposed when SMN is monomeric and sequestered when SMN forms higher-order multimers.
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Affiliation(s)
- Kelsey M Gray
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Kevin A Kaifer
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - David Baillat
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550
| | - Ying Wen
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Thomas R Bonacci
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Amanda C Raimer
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Ashlyn M Spring
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Sara Ten Have
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD15EH, UK
| | - Jacqueline J Glascock
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - Kushol Gupta
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Gregory D Van Duyne
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Michael J Emanuele
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
| | - Angus I Lamond
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD15EH, UK
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550
| | - Christian L Lorson
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - A Gregory Matera
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
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23
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Dantuma NP, Salomons FA. Ubiquitin versus misfolding: The minimal requirements for inclusion body formation. J Cell Biol 2017; 213:147-9. [PMID: 27114497 PMCID: PMC5084277 DOI: 10.1083/jcb.201603095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 04/04/2016] [Indexed: 01/11/2023] Open
Abstract
Ubiquitin-containing inclusion bodies are characteristic features of numerous neurodegenerative diseases, but whether ubiquitin plays a functional role in the formation of these protein deposits is unclear. In this issue, Bersuker et al. (2016. J. Cell Biol http://dx.doi.org/10.1083/jcb.201511024) report that protein misfolding without ubiquitylation is sufficient for translocation into inclusion bodies.
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Affiliation(s)
- Nico P Dantuma
- Department of Cell and Molecular Biology, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Florian A Salomons
- Department of Cell and Molecular Biology, Karolinska Institutet, S-17177 Stockholm, Sweden
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24
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Wang B, Zeng L, Merillat SA, Fischer S, Ochaba J, Thompson LM, Barmada SJ, Scaglione KM, Paulson HL. The ubiquitin conjugating enzyme Ube2W regulates solubility of the Huntington's disease protein, huntingtin. Neurobiol Dis 2017; 109:127-136. [PMID: 28986324 DOI: 10.1016/j.nbd.2017.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/29/2017] [Accepted: 10/01/2017] [Indexed: 12/20/2022] Open
Abstract
Huntington's disease (HD) is caused by a CAG repeat expansion that encodes a polyglutamine (polyQ) expansion in the HD disease protein, huntingtin (HTT). PolyQ expansion promotes misfolding and aggregation of mutant HTT (mHTT) within neurons. The cellular pathways, including ubiquitin-dependent processes, by which mHTT is regulated remain incompletely understood. Ube2W is the only ubiquitin conjugating enzyme (E2) known to ubiquitinate substrates at their amino (N)-termini, likely favoring substrates with disordered N-termini. By virtue of its N-terminal polyQ domain, HTT has an intrinsically disordered amino terminus. In studies employing immortalized cells, primary neurons and a knock-in (KI) mouse model of HD, we tested the effect of Ube2W deficiency on mHTT levels, aggregation and neurotoxicity. In cultured cells, deficiency of Ube2W activity markedly decreases mHTT aggregate formation and increases the level of soluble monomers, while reducing mHTT-induced cytotoxicity. Consistent with this result, the absence of Ube2W in HdhQ200 KI mice significantly increases levels of soluble monomeric mHTT while reducing insoluble oligomeric species. This study sheds light on the potential function of the non-canonical ubiquitin-conjugating enzyme, Ube2W, in this polyQ neurodegenerative disease.
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Affiliation(s)
- Bo Wang
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Program, University of Michigan, Ann Arbor, MI 48109, USA; Department of Dermatology, Ruijin Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Li Zeng
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Neurology, Sichuan Provincial Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Sean A Merillat
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Svetlana Fischer
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Joseph Ochaba
- Department of Neurobiology and Behavior, Institute of Memory Impairment and Neurological Disorders, University of California, Irvine, CA 92697, USA; Department of Psychiatry and Human Behavior, Institute of Memory Impairment and Neurological Disorders, University of California, Irvine, CA 92697, USA
| | - Leslie M Thompson
- Department of Neurobiology and Behavior, Institute of Memory Impairment and Neurological Disorders, University of California, Irvine, CA 92697, USA; Department of Psychiatry and Human Behavior, Institute of Memory Impairment and Neurological Disorders, University of California, Irvine, CA 92697, USA
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kenneth M Scaglione
- Neuroscience Research Center and Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Program, University of Michigan, Ann Arbor, MI 48109, USA.
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25
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Zhou H, Zhao J, Cai J, Patil SB. UBIQUITIN-SPECIFIC PROTEASES function in plant development and stress responses. PLANT MOLECULAR BIOLOGY 2017; 94:565-576. [PMID: 28695315 DOI: 10.1007/s11103-017-0633-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/05/2017] [Indexed: 05/08/2023]
Abstract
UBIQUITIN-SPECIFIC PROTEASES play important roles in plant development and stress responses. Protein ubiquitination and deubiquitination are reversible processes, which can modulate the stability, activity as well as subcellular localization of the substrate proteins. UBIQUITIN-SPECIFIC PROTEASE (UBP) protein family participates in protein deubiquitination. Members of UBP family are involved in a variety of physiological processes in plants, as evidenced by their functional characterization in model plant Arabidopsis and other plants. UBPs are conserved in plants and distinct UBPs function in different regulatory processes, although functional redundancies exist between some members. Here we briefly reviewed recent advances in understanding the biological functions of UBP protein family in Arabidopsis, particularly the molecular mechanisms by which UBPs regulate plant development and stress responses. We believe that elucidation of UBPs function and regulation in Arabidopsis will provide new insights about protein deubiquitination and might shed light on the understanding of the mechanistic roles of UBPs in general, which will definitely contribute to crop improvement in agriculture.
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Affiliation(s)
- Huapeng Zhou
- Key Laboratory of Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, China.
| | - Jinfeng Zhao
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Jingqing Cai
- Key Laboratory of Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, China
| | - Suyash B Patil
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
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26
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Kumasaka MY, Yajima I, Ohgami N, Ninomiya H, Iida M, Li X, Oshino R, Tanihata H, Yoshinaga M, Kato M. Manganese-Mediated Decrease in Levels of c-RET and Tyrosine Hydroxylase Expression In Vitro. Neurotox Res 2017; 32:661-670. [PMID: 28730349 DOI: 10.1007/s12640-017-9783-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 06/29/2017] [Accepted: 07/05/2017] [Indexed: 10/19/2022]
Abstract
Previous studies showed that overexposure to manganese causes parkinsonism, a disorder of dopaminergic neurons. Previous studies also showed that activity of c-RET kinase controls dopamine production through regulation of tyrosine hydroxylase (TH) expression, suggesting the involvement of c-RET in the development of parkinsonism. To our knowledge, however, there is no report showing a correlation between manganese-mediated parkinsonism and c-RET. In this study, we examined the effect of manganese on the expression and/or activation levels of c-RET and TH in human TH-expressing cells (TGW cells). We first found that treatment with 30 and 100 μM manganese resulted in reduction of c-RET transcript level and degradation of c-RET protein through promotion of ubiquitination. We then examined the biological significance of manganese-mediated decrease of c-RET protein expression. Decreased TH expression with decreased c-RET kinase activity was observed in c-RET protein-depleted TGW cells by treatment with manganese (30 μM) as well as by c-RET siRNA transfection. Since TH protein has been shown to be involved in the dopamine-producing pathway in previous studies, our results indicate the possibility that manganese-mediated reduction of TH expression and phosphorylation via decreased expression of c-RET protein in neural cells is involved in parkinsonism induced by manganese.
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Affiliation(s)
- Mayuko Y Kumasaka
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.,Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai-shi, Aichi, 487-8501, Japan.,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Ichiro Yajima
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.,Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai-shi, Aichi, 487-8501, Japan.,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Nobutaka Ohgami
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.,Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai-shi, Aichi, 487-8501, Japan.,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Hiromasa Ninomiya
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Machiko Iida
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.,Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai-shi, Aichi, 487-8501, Japan.,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Xiang Li
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Reina Oshino
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Hiroko Tanihata
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Masafumi Yoshinaga
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Masashi Kato
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan. .,Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai-shi, Aichi, 487-8501, Japan. .,Voluntary Body for International Health Care in Universities, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.
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27
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Cheng MC, Kuo WC, Wang YM, Chen HY, Lin TP. UBC18 mediates ERF1 degradation under light-dark cycles. THE NEW PHYTOLOGIST 2017; 213:1156-1167. [PMID: 27787902 DOI: 10.1111/nph.14272] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/11/2016] [Indexed: 05/05/2023]
Abstract
Ethylene Response Factor 1 (ERF1) plays a crucial role in biotic and abiotic stress responses. Previous studies have shown that ERF1 regulates stress-responsive gene expression by binding to different cis-acting elements in response to various stress signals. ERF1 was also reported to be unstable in the dark, and it regulates hypocotyl elongation. Here, we elucidated the mechanism underlying degradation of ERF1. Yeast two-hybrid screening showed that UBIQUITIN-CONJUGATING ENZYME 18 (UBC18) interacted with ERF1. The interaction between ERF1 and UBC18 was verified using pull-down assays and coimmunoprecipitation analyses. We then compared the ERF1 protein abundance in the UBC18 mutant and overexpression plants. Based on the results of protein degradation and in vivo ubiquitination assays, we proposed that UBC18 mediates ERF1 ubiquitination and degradation. ERF1 was more stable in UBC18 mutants and less stable in UBC18 overexpression lines compared with that in wild-type plants. ERF1 was degraded by the 26S proteasome system via regulation of UBC18 and promotes dark-repression of downstream genes and proline accumulation. UBC18 negatively regulated drought and salt stress responses by altering the abundance of ERF1 and the expression of genes downstream of ERF1.
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Affiliation(s)
- Mei-Chun Cheng
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Wen-Chieh Kuo
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Yi-Ming Wang
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Hsing-Yu Chen
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Tsan-Piao Lin
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
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28
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Translational and post-translational regulation of mouse cation transport regulator homolog 1. Sci Rep 2016; 6:28016. [PMID: 27302742 PMCID: PMC4908420 DOI: 10.1038/srep28016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 05/27/2016] [Indexed: 01/15/2023] Open
Abstract
Cation transport regulator homolog 1 (Chac1) is an endoplasmic reticulum (ER) stress inducible gene that has a function as a γ-glutamyl cyclotransferase involved in the degradation of glutathione. To characterize the translation and stability of Chac1, we found that the Kozak-like sequence present in the 5′ untranslated region (5′UTR) of the Chac1 mRNA was responsible for Chac1 translation. In addition, the short form (ΔChac1), which translated from the second ATG codon, was generated in the absence of the 5′UTR. The proteasome pathway predominantly participated in the stability of the Chac1 protein; however, its expression was remarkably up-regulated by co-transfection with ubiquitin genes. Using an immunoprecipitation assay, we revealed that ubiquitin molecule was directly conjugated to Chac1, and that mutated Chac1 with all lysine residues replaced by arginine was also ubiquitinated. Finally, we showed that WT Chac1 but not ΔChac1 reduced the intracellular level of glutathione. Taken together, our results suggest that the Chac1 protein expression is regulated in translational and post-translational fashion due to the Kozak-like sequence in the 5′UTR and the ubiquitin-mediated pathways. The bidirectional roles of ubiquitination in regulating Chac1 stabilization might give us a new insight into understanding the homeostasis of glutathione under pathophysiological conditions.
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29
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Selective role of autophagy in neuronal function and neurodegenerative diseases. Neurosci Bull 2016; 31:379-81. [PMID: 26254057 DOI: 10.1007/s12264-015-1551-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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30
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Shen WC, Li HY, Chen GC, Chern Y, Tu PH. Mutations in the ubiquitin-binding domain of OPTN/optineurin interfere with autophagy-mediated degradation of misfolded proteins by a dominant-negative mechanism. Autophagy 2016; 11:685-700. [PMID: 25484089 DOI: 10.4161/auto.36098] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OPTN (optineurin) is an autophagy receptor and mutations in the OPTN gene result in familial glaucoma (E50K) and amyotrophic lateral sclerosis (ALS) (E478G). However, the mechanisms through which mutant OPTN leads to human diseases remain to be characterized. Here, we demonstrated that OPTN colocalized with inclusion bodies (IBs) formed by mutant HTT/huntingtin protein (mHTT) in R6/2 transgenic mice and IBs formed by 81QNmHTT (nuclear form), 109QmHTT (cytoplasmic form) or the truncated form of TARDBP/TDP-43 (TARDBP(ND251)) in Neuro2A cells. This colocalization required the ubiquitin (Ub)-binding domain (UbBD, amino acids 424 to 511) of OPTN. Overexpression of wild-type (WT) OPTN decreased IBs through K63-linked polyubiquitin-mediated autophagy. E50K or 210 to 410Δ (with amino acids 210 to 410 deleted) whose mutation or deletion was outside the UbBD decreased the IBs formed by 109QmHTT or TARDBP(ND251), as was the case with WT OPTN. In contrast, UbBD mutants, including E478G, D474N, UbBDΔ, 411 to 520Δ and 210 to 520Δ, increased accumulation of IBs. UbBD mutants (E478G, UbBDΔ) retained a substantial ability to interact with WT OPTN, and were found to colocalize with polyubiquitinated IBs, which might occur indirectly through their WT partner in a WT-mutant complex. They decreased autophagic flux evidenced by alteration in LC3 level and turnover and in the number of LC3-positive puncta under stresses like starvation or formation of IBs. UbBD mutants exhibited a weakened interaction with MYO6 (myosin VI) and TOM1 (target of myb1 homolog [chicken]), important for autophagosome maturation, in cells or sorted 109QmHtt IBs. Taken together, our data indicated that UbBD mutants acted as dominant-negative traps through the formation of WT-mutant hybrid complexes to compromise the maturation of autophagosomes, which in turn interfered with OPTN-mediated autophagy and clearance of IBs.
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Key Words
- ALS, amyotrophic lateral sclerosis
- Ab, antibody
- BafA1, bafilomycin A1
- CCD, coiled-coil domain
- Ef, FRET efficiency
- FT, filter-trap assay
- HD, Huntington disease
- IBs, inclusion bodies
- IP, immunoprecipitation
- K48, lysine 48
- K63, lysine 63
- LIR, LC3-interacting region
- MYO6, myosin VI
- OPTN, optineurin
- PBS, phosphate-buffered saline
- PFA, paraformaldehyde
- TARDBP/TDP-43
- TARDBP/TDP-43, TAR DNA-binding protein
- TBK1, TANK-binding kinase 1
- TUBA, alpha tubulin
- UPS, ubiquitin-proteasome system
- Ub, ubiquitin B/C/D
- UbBD, ubiquitin-binding domain
- WB, western blot
- WT, wild type
- autophagy
- dominant-negative
- huntingtin
- mHTT, mutant huntingtin
- optineurin
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Affiliation(s)
- Wen-Chuan Shen
- a Taiwan International Graduate Program in Molecular Medicine; National Yang-Ming University and Academia Sinica ; Taipei , Taiwan
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31
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Zhang CW, Adeline HB, Chai BH, Hong ET, Ng CH, Lim KL. Pharmacological or Genetic Activation of Hsp70 Protects against Loss of Parkin Function. NEURODEGENER DIS 2016; 16:304-16. [DOI: 10.1159/000443668] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 12/23/2015] [Indexed: 11/19/2022] Open
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32
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Zhou Z, Xu C, Chen P, Liu C, Pang S, Yao X, Zhang Q. Stability of HIB-Cul3 E3 ligase adaptor HIB Is Regulated by Self-degradation and Availability of Its Substrates. Sci Rep 2015; 5:12709. [PMID: 26263855 PMCID: PMC4533009 DOI: 10.1038/srep12709] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 07/06/2015] [Indexed: 12/29/2022] Open
Abstract
The HIB-Cul3 complex E3 ligase regulates physiological homeostasis through regulating its substrate stability and its activity can be modulated by changing HIB abundance. However, regulation of HIB remains elusive. Here we provide evidence that HIB is degraded through the proteasome by Cul3-mediated polyubiquitination in K48 manner in Drosophila. Strikingly, HIB is targeted for degradation by itself. We further identify that three degrons (52LKSS56T, 76LDEE80S and 117MESQ121R) and K185 and K198 of HIB are essential for its auto-degradation. Finally, we demonstrate that HIB-Cul3 substrates, Ci and Puc, can effectively protect HIB from HIB-Cul3-mediated degradation. Taken together, our study indicates that there is an exquisite equilibrium between the adaptor and targets to achieve the tight control of the HIB, which is essential for maintaining suitable Hh and JNK signaling. And the mechanism of adaptor self-degradation and reciprocal control of the abundance between adaptor and its substrates is also applied to BTB-Cul3 E3 ligase adaptor dKeap1, dDiablo and dKLHL18.
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Affiliation(s)
- Zizhang Zhou
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, 210061, China
| | - Congyu Xu
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, 210061, China
| | - Ping Chen
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, 210061, China
| | - Chen Liu
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, 210061, China
| | - Shu Pang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, 210061, China
| | - Xia Yao
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, 210061, China
| | - Qing Zhang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, 210061, China
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33
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Lim GGY, Chua DSK, Basil AH, Chan HY, Chai C, Arumugam T, Lim KL. Cytosolic PTEN-induced Putative Kinase 1 Is Stabilized by the NF-κB Pathway and Promotes Non-selective Mitophagy. J Biol Chem 2015; 290:16882-93. [PMID: 25987559 DOI: 10.1074/jbc.m114.622399] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Indexed: 11/06/2022] Open
Abstract
The potential cellular function of the 53-kDa cytosolic form of PINK1 (PINK1-53) is often overlooked because of its rapid degradation by the proteasome upon its production. Although a number of recent studies have suggested various roles for PINK1-53, how this labile PINK1 species attains an adequate expression level to fulfil these roles remains unclear. Here we demonstrated that PINK1-53 is stabilized in the presence of enhanced Lys-63-linked ubiquitination and identified TRAF6-related NF-κB activation as a novel pathway involved in this. We further showed that a mimetic of PINK1-53 promotes mitophagy but, curiously, in apparently healthy mitochondria. We speculate that this "non-selective" form of mitophagy may potentially help to counteract the build-up of reactive oxygen species in cells undergoing oxidative stress and, as such, represent a cytoprotective response.
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Affiliation(s)
- Grace G Y Lim
- From the Neurodegeneration Research Laboratory, National Neuroscience Institute, Singapore, the Department of Physiology
| | - Doreen S K Chua
- From the Neurodegeneration Research Laboratory, National Neuroscience Institute, Singapore, the Department of Physiology, National University of Singapore, Graduate School for Integrative Sciences and Engineering, National University of Singapore, and
| | - Adeline H Basil
- From the Neurodegeneration Research Laboratory, National Neuroscience Institute, Singapore
| | - Hui-Ying Chan
- From the Neurodegeneration Research Laboratory, National Neuroscience Institute, Singapore
| | - Chou Chai
- From the Neurodegeneration Research Laboratory, National Neuroscience Institute, Singapore
| | | | - Kah-Leong Lim
- From the Neurodegeneration Research Laboratory, National Neuroscience Institute, Singapore, the Department of Physiology, National University of Singapore, Graduate School for Integrative Sciences and Engineering, National University of Singapore, and the Duke-National University of Singapore Graduate Medical School, Singapore
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34
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Morgan RE, Chudasama V, Moody P, Smith MEB, Caddick S. A novel synthetic chemistry approach to linkage-specific ubiquitin conjugation. Org Biomol Chem 2015; 13:4165-8. [PMID: 25736233 PMCID: PMC4372856 DOI: 10.1039/c5ob00130g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 02/24/2015] [Indexed: 11/21/2022]
Abstract
Ubiquitination is of great importance as the post-translational modification of proteins with ubiquitin, or ubiquitin chains, facilitates a number of vital cellular processes. Herein we present a facile method of preparing various ubiquitin conjugates under mild conditions using michael acceptors based on dibromo-maleimides and dibromo-pyridazinediones.
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Affiliation(s)
- Rachel E. Morgan
- Department of Chemistry , University College London , 20 Gordon Street , London , UK . ; Fax: +44 (0)20 7679 7463 ; Tel: +44 (0)20 3108 5071
| | - Vijay Chudasama
- Department of Chemistry , University College London , 20 Gordon Street , London , UK . ; Fax: +44 (0)20 7679 7463 ; Tel: +44 (0)20 3108 5071
| | - Paul Moody
- Department of Chemistry , University College London , 20 Gordon Street , London , UK . ; Fax: +44 (0)20 7679 7463 ; Tel: +44 (0)20 3108 5071
| | - Mark E. B. Smith
- Department of Chemistry , University College London , 20 Gordon Street , London , UK . ; Fax: +44 (0)20 7679 7463 ; Tel: +44 (0)20 3108 5071
| | - Stephen Caddick
- Department of Chemistry , University College London , 20 Gordon Street , London , UK . ; Fax: +44 (0)20 7679 7463 ; Tel: +44 (0)20 3108 5071
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35
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Erpapazoglou Z, Walker O, Haguenauer-Tsapis R. Versatile roles of k63-linked ubiquitin chains in trafficking. Cells 2014; 3:1027-88. [PMID: 25396681 PMCID: PMC4276913 DOI: 10.3390/cells3041027] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/14/2014] [Accepted: 10/21/2014] [Indexed: 12/11/2022] Open
Abstract
Modification by Lys63-linked ubiquitin (UbK63) chains is the second most abundant form of ubiquitylation. In addition to their role in DNA repair or kinase activation, UbK63 chains interfere with multiple steps of intracellular trafficking. UbK63 chains decorate many plasma membrane proteins, providing a signal that is often, but not always, required for their internalization. In yeast, plants, worms and mammals, this same modification appears to be critical for efficient sorting to multivesicular bodies and subsequent lysosomal degradation. UbK63 chains are also one of the modifications involved in various forms of autophagy (mitophagy, xenophagy, or aggrephagy). Here, in the context of trafficking, we report recent structural studies investigating UbK63 chains assembly by various E2/E3 pairs, disassembly by deubiquitylases, and specifically recognition as sorting signals by receptors carrying Ub-binding domains, often acting in tandem. In addition, we address emerging and unanticipated roles of UbK63 chains in various recycling pathways that function by activating nucleators required for actin polymerization, as well as in the transient recruitment of signaling molecules at the plasma or ER membrane. In this review, we describe recent advances that converge to elucidate the mechanisms underlying the wealth of trafficking functions of UbK63 chains.
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Affiliation(s)
- Zoi Erpapazoglou
- Institut Jacques Monod-CNRS, UMR 7592, Université-Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
| | - Olivier Walker
- Institut des Sciences Analytiques, UMR5280, Université de Lyon/Université Lyon 1, 69100 Villeurbanne, France.
| | - Rosine Haguenauer-Tsapis
- Institut Jacques Monod-CNRS, UMR 7592, Université-Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
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Immunohistochemical analysis of the ubiquitin proteasome system and autophagy lysosome system induced after traumatic intracranial injury: association with time between the injury and death. Am J Forensic Med Pathol 2014; 35:38-44. [PMID: 24317096 DOI: 10.1097/paf.0000000000000067] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This study aimed to analyze how the ubiquitin proteasome system (UPS) or autophagy lysosome system (autophagy) are induced in brain tissues at different intervals after traumatic intracranial injury in humans. Injured cerebral cortices of 36 forensic autopsy cases were analyzed by immunohistochemistry using antibodies as the UPS marker (ubiquitin and lysine 48-linked polyubiquitin chains [K48]) and autophagy marker (lysine 63-linked polyubiquitin chains [K63], p62/sequestome 1 and microtubule-associated protein 1 light chain 3 [LC3]). The number of neurons and glial cells with cytoplasmic inclusions that stained positive for ubiquitin, K48, and p62 began to increase within 1 hour after intracranial injury, particularly at contusion sites. From 3.5 hours onward, an increase in cytoplasmic inclusions that stained positive for K63 and LC3 began to be detected. LC3-positive cytoplasmic inclusions were not identified after 37 days; however, the increased immunoreactivity to ubiquitin and anti-K48 antibody was maintained for 7 months. These results suggest that the UPS is activated earlier and lasts longer than autophagy, that autophagy is activated for a relatively short term (between a few hours and approximately 1 month), and that the activation occurs especially in severely damaged brain tissues following head trauma in humans.
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37
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Zhu X, Zhang J, Sun H, Jiang C, Dong Y, Shan Q, Su S, Xie Y, Xu N, Lou X, Liu S. Ubiquitination of inositol-requiring enzyme 1 (IRE1) by the E3 ligase CHIP mediates the IRE1/TRAF2/JNK pathway. J Biol Chem 2014; 289:30567-30577. [PMID: 25225294 DOI: 10.1074/jbc.m114.562868] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deciphering the inositol-requiring enzyme 1 (IRE1) signaling pathway is fundamentally important for understanding the unfolded protein response (UPR). The ubiquitination of proteins residing on the endoplasmic reticulum (ER) membrane has been reported to be involved in the UPR, although the mechanism has yet to be fully elucidated. Using immunoprecipitation and mass spectrometry, IRE1 was identified as a substrate of the E3 ligase CHIP (carboxyl terminus of HSC70-interacting protein) in HEK293 cells under geldanamycin-induced ER stress. Two residues of IRE1, Lys(545) and Lys(828), were targeted for Lys(63)-linked ubiquitination. Moreover, in CHIP knockdown cells, IRE1 phosphorylation and the IRE1-TRAF2 interaction were nearly abolished under ER stress, which may be due to lacking ubiquitination of IRE1 on Lys(545) and Lys(828), respectively. The cellular responses were evaluated, and the data indicated that CHIP-regulated IRE1/TRAF2/JNK signaling antagonized the senescence process. Therefore, our findings suggest that CHIP-mediated ubiquitination of IRE1 contributes to the dynamic regulation of the UPR.
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Affiliation(s)
- Xu Zhu
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China,; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ju Zhang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Huiying Sun
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Cuicui Jiang
- Beijing Protein Innovation, Beijing 101318, China, and
| | - Yusheng Dong
- Beijing Protein Innovation, Beijing 101318, China, and
| | - Qiang Shan
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Siyuan Su
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China,; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingying Xie
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China,; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ningzhi Xu
- Laboratory of Cell and Molecular Biology, Cancer Institute and Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Xiaomin Lou
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China,.
| | - Siqi Liu
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China,; University of Chinese Academy of Sciences, Beijing 100049, China,.
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38
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Ubiquitin-activating enzyme activity contributes to differential accumulation of mutant huntingtin in brain and peripheral tissues. J Neurosci 2014; 34:8411-22. [PMID: 24948797 DOI: 10.1523/jneurosci.0775-14.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Huntington's disease (HD) belongs to a family of neurodegenerative diseases caused by misfolded proteins and shares the pathological hallmark of selective accumulation of misfolded proteins in neuronal cells. Polyglutamine expansion in the HD protein, huntingtin (Htt), causes selective neurodegeneration that is more severe in the striatum and cortex than in other brain regions, but the mechanism behind this selectivity is unknown. Here we report that in HD knock-in mice, the expression levels of mutant Htt (mHtt) are higher in brain tissues than in peripheral tissues. However, the expression of N-terminal mHtt via stereotaxic injection of viral vectors in mice also results in greater accumulation of mHtt in the striatum than in muscle. We developed an in vitro assay that revealed that extracts from the striatum and cortex promote the formation of high-molecular weight (HMW) mHtt compared with the relatively unaffected cerebellar and peripheral tissue extracts. Inhibition of ubiquitin-activating enzyme E1 (Ube1) increased the levels of HMW mHtt in the relatively unaffected tissues. Importantly, the expression levels of Ube1 are lower in brain tissues than peripheral tissues and decline in the nuclear fraction with age, which is correlated with the increased accumulation of mHtt in the brain and neuronal nuclei during aging. Our findings suggest that decreased targeting of misfolded Htt to the proteasome for degradation via Ube1 may underlie the preferential accumulation of toxic forms of mHtt in the brain and its selective neurodegeneration.
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39
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Evers MM, Toonen LJA, van Roon-Mom WMC. Ataxin-3 protein and RNA toxicity in spinocerebellar ataxia type 3: current insights and emerging therapeutic strategies. Mol Neurobiol 2014; 49:1513-31. [PMID: 24293103 PMCID: PMC4012159 DOI: 10.1007/s12035-013-8596-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/14/2013] [Indexed: 01/10/2023]
Abstract
Ataxin-3 is a ubiquitously expressed deubiqutinating enzyme with important functions in the proteasomal protein degradation pathway and regulation of transcription. The C-terminus of the ataxin-3 protein contains a polyglutamine (PolyQ) region that, when mutationally expanded to over 52 glutamines, causes the neurodegenerative disease spinocerebellar ataxia 3 (SCA3). In spite of extensive research, the molecular mechanisms underlying the cellular toxicity resulting from mutant ataxin-3 remain elusive and no preventive treatment is currently available. It has become clear over the last decade that the hallmark intracellular ataxin-3 aggregates are likely not the main toxic entity in SCA3. Instead, the soluble PolyQ containing fragments arising from proteolytic cleavage of ataxin-3 by caspases and calpains are now regarded to be of greater influence in pathogenesis. In addition, recent evidence suggests potential involvement of a RNA toxicity component in SCA3 and other PolyQ expansion disorders, increasing the pathogenic complexity. Herein, we review the functioning of ataxin-3 and the involvement of known protein and RNA toxicity mechanisms of mutant ataxin-3 that have been discovered, as well as future opportunities for therapeutic intervention.
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Affiliation(s)
- Melvin M. Evers
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Lodewijk J. A. Toonen
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Willeke M. C. van Roon-Mom
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
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40
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Characterization of the ubiquitin-modified proteome regulated by transient forebrain ischemia. J Cereb Blood Flow Metab 2014; 34:425-32. [PMID: 24301296 PMCID: PMC3948117 DOI: 10.1038/jcbfm.2013.210] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/05/2013] [Accepted: 11/05/2013] [Indexed: 02/04/2023]
Abstract
Ubiquitylation is a posttranslational protein modification that modulates various cellular processes of key significance, including protein degradation and DNA damage repair. In animals subjected to transient cerebral ischemia, ubiquitin-conjugated proteins accumulate in Triton-insoluble aggregates. Although this process is widely considered to modulate the fate of postischemic neurons, few attempts have been made to characterize the ubiquitin-modified proteome in these aggregates. We performed proteomics analyses to identify ubiquitylated proteins in postischemic aggregates. Mice were subjected to 10 minutes of forebrain ischemia and 4 hours of reperfusion. The hippocampi were dissected, aggregates were isolated, and trypsin-digested after spiking with GG-BSA as internal standard. K-ɛ-GG-containing peptides were immunoprecipitated and analyzed by label-free quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. We identified 1,664 peptides to 520 proteins containing at least one K-ɛ-GG. Sixty-six proteins were highly ubiquitylated, with 10 or more K-ɛ-GG peptides. Based on selection criteria of greater than fivefold increase and P<0.001, 763 peptides to 272 proteins were highly enriched in postischemic aggregates. These included proteins involved in important neuronal functions and signaling pathways that are impaired after ischemia. Results of this study could serve as an important platform to uncover the mechanisms linking insoluble ubiquitin aggregates to the functions of postischemic neurons.
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41
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Abstract
Adult neural stem cells contribute to neurogenesis and plasticity of the brain which is essential for central regulation of systemic homeostasis. Damage to these homeostatic components, depending on locations in the brain, poses threat to impaired neurogenesis, neurodegeneration, cognitive loss and energy imbalance. Recent research has identified brain metabolic inflammation via proinflammatory IκB kinase-β (IKKβ) and its downstream nuclear transcription factor NF-κB pathway as a non-classical linker of metabolic and neurodegenerative disorders. Chronic activation of the pathway results in impairment of energy balance and nutrient metabolism, impediment of neurogenesis, neural stem cell proliferation and differentiation, collectively converging on metabolic and cognitive decline. Hypothalamic IKKβ/NF-κB via inflammatory crosstalk between microglia and neurons has been discovered to direct systemic aging by inhibiting the production of gonadotropin-releasing hormone (GnRH) and inhibition of inflammation or GnRH therapy could revert aging related degenerative symptoms at least in part. This article reviews the crucial role of hypothalamic inflammation in affecting neural stem cells which mediates the neurodegenerative mechanisms of causing metabolic derangements as well as aging-associated disorders or diseases.
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Affiliation(s)
| | - Dongsheng Cai
- Address correspondence to: Dongsheng Cai, M.D., Ph.D., Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, Phone: 718-430-2426, Fax: 718-430-2433,
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42
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Sakai K, Fukuda T, Iwadate K. Beading of the astrocytic processes (clasmatodendrosis) following head trauma is associated with protein degradation pathways. Brain Inj 2013; 27:1692-7. [PMID: 24111565 DOI: 10.3109/02699052.2013.837198] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVES To present the incidence of clasmatodendrosis (injured astrocytic processes) and analyse the association between clasmatodendrosis and the ubiquitin proteasome system (UPS) and autophagy lysosome system (autophagy). METHODS The injured cerebral cortices of 36 autopsy cases were analysed by light microscopy by immunohistochemistry using an anti-glial fibrillary acidic protein (GFAP) antibody and UPS marker antibodies (ubiquitin and lysine 48-linked polyubiquitin chains (K(48)) and autophagy marker (lysine 63-linked polyubiquitin chains (K(63)), p62/sequestosome 1 and microtubule-associated protein 1 light chain 3 [LC3]). Double-immunofluorescence staining was used to detect the relationships between p62-K(48), p62-K(63) and GFAP-K(48). RESULTS Clasmatodendrosis that was immunoreactive to GFAP or K(48) was detected by 1 hour up to 14 days following head trauma. The survival time of cases with clasmatodendrosis was significantly shorter than that in cases without clasmatodendrosis (p < 0.01). Involvement of contusion or oedema was significantly frequent in cases with clasmatodendrosis (p < 0.01). There was no significant age difference between cases with clasmatodendrosis and cases without clasmatodendrosis (p = 0.18). Double-immunofluorescence staining for p62-K(48) and GFAP-K(48) demonstrated clasmatodendrosis with overlapping fluorescence signals. CONCLUSION Clasmatodendrosis is associated with UPS-mediated, autophagy and relatively acute pathological findings after traumatic intracranial injury.
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43
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Xu Y, Her C. VBP1 facilitates proteasome and autophagy-mediated degradation of MutS homologue hMSH4. FASEB J 2013; 27:4799-810. [PMID: 23964080 DOI: 10.1096/fj.13-235127] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ubiquitination is an important mechanism for the regulation of diverse cellular functions, including proteolysis and DNA repair. The human MutS family protein hMSH4 functions in meiotic recombinational DNA double-strand break (DSB) repair. It was previously observed that hMSH4 interacts with the von Hippel-Lindau binding protein 1 (VBP1), a partner of the VHL ubiquitin E3 ligase as well as a subunit of the prefoldin complex. In this study we address how ubiquitination regulates the homeostasis of hMSH4 in the human embryonic kidney cell line HEK293T. We demonstrate that VBP1 targets hMSH4 for degradation and identify a new VBP1 binding partner, p97, an AAA(+) ATPase involved in protein degradation and DNA damage response. VBP1, VHL, and p97 coexist in the hMSH4 immunocomplex and regulate the polyubiquitination of hMSH4. Furthermore, the results of this study demonstrate that VBP1 acts together with p97 to regulate hMSH4 degradation. Overall, this study has revealed a molecular mechanism by which VBP1 controls the levels of hMSH4 by ubiquitination in mitotic cells. Such a mechanism may be important for controlling the role of hMSH4 in regulating homologous recombination and nonhomologous DNA end joining-mediated DSB repair in human cells.
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Affiliation(s)
- Yang Xu
- 1School of Molecular Biosciences, Mail Drop 64-7520, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7520, USA.
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44
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Gavilán E, Sánchez-Aguayo I, Daza P, Ruano D. GSK-3β signaling determines autophagy activation in the breast tumor cell line MCF7 and inclusion formation in the non-tumor cell line MCF10A in response to proteasome inhibition. Cell Death Dis 2013; 4:e572. [PMID: 23559006 PMCID: PMC3668630 DOI: 10.1038/cddis.2013.95] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ubiquitin–proteasome system and the autophagy–lysosome pathway are the two main mechanisms for eukaryotic intracellular protein degradation. Proteasome inhibitors are used for the treatment of some types of cancer, whereas autophagy seems to have a dual role in tumor cell survival and death. However, the relationship between both pathways has not been extensively studied in tumor cells. We have investigated both proteolytic systems in the human epithelial breast non-tumor cell line MCF10A and in the human epithelial breast tumor cell line MCF7. In basal condition, tumor cells showed a lower proteasome function but a higher autophagy activity when compared with MCF10A cells. Importantly, proteasome inhibition (PI) leads to different responses in both cell types. Tumor cells showed a dose-dependent glycogen synthase kinase-3 (GSK-3)β inhibition, a huge increase in the expression of the transcription factor CHOP and an active processing of caspase-8. By contrast, MCF10A cells fully activated GSK-3β and showed a lower expression of both CHOP and processed caspase-8. These molecular differences were reflected in a dose-dependent autophagy activation and cell death in tumor cells, while non-tumor cells exhibited the formation of inclusion bodies and a decrease in the cell death rate. Importantly, the behavior of the MCF7 cells can be reproduced in MCF10A cells when GSK-3β and the proteasome were simultaneously inhibited. Under this situation, MCF10A cells strongly activated autophagy, showing minimal inclusion bodies, increased CHOP expression and cell death rate. These findings support GSK-3β signaling as a key mechanism in regulating autophagy activation or inclusion formation in human tumor or non-tumor breast cells, respectively, which may shed new light on breast cancer control.
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Affiliation(s)
- E Gavilán
- Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocío, Universidad de Sevilla, Sevilla, Spain
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45
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Abstract
Inflammation is a biological response mounted by the immune system against dangerous assaults that threaten the integrity and normal physiology of an organism. During the past decades, cross-disciplinary research from immunology and endocrinology has much broadened this knowledge by demonstrating that chronic conditions of nutritional excess constitute an independent category of inflammatory activators, and the resulting chronic and low-grade inflammation is an important characteristic of overnutrition-induced diseases. A large body of research has demonstrated that these diseases are pathogenically associated with the local, negative actions of inflammation in peripheral tissues predominantly including the liver, muscle, and fat. In this research background, more recent research has advanced to a new level, with the important discoveries showing that overnutrition-induced inflammation occurs in the brain and thus plays a broad and leadership role in overnutrition-induced diseases. While much more research establishments are expected in this emerging and quickly expanding research, the appreciated understandings have been mainly based on proinflammatory IKKβ/NF-κB pathway and related molecules in the hypothalamus. In this chapter, the author focuses on describing IKKβ/NF-κB-induced neural inflammation in the context of overnutrition-induced metabolic inflammation and especially the central roles of this neural inflammation in the development of a spectrum of overnutrition-related diseases.
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Affiliation(s)
- Dongsheng Cai
- Department of Molecular Pharmacology, Institute of Aging, Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA.
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46
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The brake within: Mechanisms of intrinsic regulation of axon growth featuring the Cdh1-APC pathway. Transl Neurosci 2013. [DOI: 10.2478/s13380-013-0125-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractNeurons of the central nervous system (CNS) form a magnificent network destined to control bodily functions and human behavior for a lifetime. During development of the CNS, neurons extend axons that establish connections to other neurons. Axon growth is guided by extrinsic cues and guidance molecules. In addition to environmental signals, intrinsic programs including transcription and the ubiquitin proteasome system (UPS) have been implicated in axon growth regulation. Over the past few years it has become evident that the E3 ubiquitin ligase Cdh1-APC together with its associated pathway plays a central role in axon growth suppression. By elucidating the intricate interplay of extrinsic and intrinsic mechanisms, we can enhance our understanding of why axonal regeneration in the CNS fails and obtain further insight into how to stimulate successful regeneration after injury.
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47
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Dosemeci A, Thein S, Yang Y, Reese TS, Tao-Cheng JH. CYLD, a deubiquitinase specific for lysine63-linked polyubiquitins, accumulates at the postsynaptic density in an activity-dependent manner. Biochem Biophys Res Commun 2012; 430:245-9. [PMID: 23146630 DOI: 10.1016/j.bbrc.2012.10.131] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 10/30/2012] [Indexed: 11/16/2022]
Abstract
Polyubiquitin chains on proteins flag them for distinct fates depending on the type of polyubiquitin linkage. While lysine48-linked polyubiquitination directs proteins to proteasomal degradation, lysine63-linked polyubiquitination promotes different protein trafficking and is involved in autophagy. Here we show that postsynaptic density (PSD) fractions from adult rat brain contain deubiquitinase activity that targets both lysine48 and lysine63-linked polyubiquitins. Comparison of PSD fractions with parent subcellular fractions by Western immunoblotting reveals that CYLD, a deubiquitinase specific for lysine63-linked polyubiquitins, is highly enriched in the PSD fraction. Electron microscopic examination of hippocampal neurons in culture under basal conditions shows immunogold label for CYLD at the PSD complex in approximately one in four synapses. Following depolarization by exposure to high K+, the proportion of CYLD-labeled PSDs as well as the labeling intensity of CYLD at the PSD increased by more than eighty percent, indicating that neuronal activity promotes accumulation of CYLD at the PSD. An increase in postsynaptic CYLD following activity would promote removal of lysine63-polyubiquitins from PSD proteins and thus could regulate their trafficking and prevent their autophagic degradation.
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Affiliation(s)
- Ayse Dosemeci
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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48
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Guglielmotto M, Monteleone D, Boido M, Piras A, Giliberto L, Borghi R, Vercelli A, Fornaro M, Tabaton M, Tamagno E. Aβ1-42-mediated down-regulation of Uch-L1 is dependent on NF-κB activation and impaired BACE1 lysosomal degradation. Aging Cell 2012; 11:834-44. [PMID: 22726800 DOI: 10.1111/j.1474-9726.2012.00854.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Amyloid-β 1-42 accumulation is the major pathogenetic event in Alzheimer's disease (AD), believed to be responsible for synaptic dysfunction and neuronal cell death. However, the physiologic activity of Aβ peptides remains elusive: Aβ might not only play a toxic role, but also act as a functional signaling intermediate. We recently reported that Aβ1-42 promotes BACE1 transcription through the activation of the JNK-c-jun pathway. Here, we show that the Aβ1-42-mediated increase in BACE1 expression is accompanied by a decrease in ubiquitin C-terminal hydrolase L1 (Uch-L1) expression and activity in different cellular models such as neuroblastoma SH-SY5Y as well as NT(2) neuronal cells. We also found that the increase in BACE1 and the decrease in Uch-L1 are related events and depend on NF-κB pathway; thus, Aβ1-42 is able to activate NF-κB pathway and the pretreatment with a pharmacological inhibitor, able to block the nuclear translocation of the transactivating unit p65, almost completely prevents both the decrease in Uch-L1 and the increase in BACE1 expression. In addition, the decrease in Uch-L1 activity interferes with the lysosomal degradation of BACE1, as demonstrated by the decrease in Cathepsin D activity and the partial accumulation of BACE1 in lysosomes after Aβ1-42 treatment as well after Uch-L1 inhibition. In support of the in vitro data, we observed low protein levels of Uch-L1 associated with high protein levels of BACE1 in sporadic AD brains. Our data suggest that Uch-L1 could be an attractive target for the development of new therapeutic approaches for AD.
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Affiliation(s)
- Michela Guglielmotto
- Department of Experimental Medicine and Oncology, University of Torino, Torino, Italy
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49
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van Tijn P, Dennissen FJA, Gentier RJG, Hobo B, Hermes D, Steinbusch HWM, Van Leeuwen FW, Fischer DF. Mutant ubiquitin decreases amyloid β plaque formation in a transgenic mouse model of Alzheimer's disease. Neurochem Int 2012; 61:739-48. [PMID: 22797007 DOI: 10.1016/j.neuint.2012.07.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 07/02/2012] [Accepted: 07/04/2012] [Indexed: 12/12/2022]
Abstract
The mutant ubiquitin UBB(+1) is a substrate as well as an inhibitor of the ubiquitin-proteasome system (UPS) and accumulates in the neuropathological hallmarks of Alzheimer's disease (AD). A role for the UPS has been suggested in the generation of amyloid β (Aβ) plaques in AD. To investigate the effect of UBB(+1) expression on amyloid pathology in vivo, we crossed UBB(+1) transgenic mice with a transgenic line expressing AD-associated mutant amyloid precursor protein (APPSwe) and mutant presenilin 1 (PS1dE9), resulting in APPPS1/UBB(+1) triple transgenic mice. In these mice, we determined the Aβ levels at 3, 6, 9 and 11 months of age. Surprisingly, we found a significant decrease in Aβ deposition in amyloid plaques and levels of soluble Aβ(42) in APPPS1/UBB(+1) transgenic mice compared to APPPS1 mice at 6 months of age, without alterations in UBB(+1) protein levels or proteasomal chymotrypsin activity. These lowering effects of UBB(+1) on Aβ deposition were transient, as this relative decrease in plaque load was not significant in APPPS1/UBB(+1) mice at 9 and 11 months of age. We also show that APPPS1/UBB(+1) mice exhibit astrogliosis, indicating that they may not be improved functionally compared to APPPS1 mice despite the Aβ reduction. The molecular mechanism underlying this decrease in Aβ deposition in APPPS1/UBB(+1) mice is more complex than previously assumed because UBB(+1) is also ubiquitinated at K63 opening the possibility of additional effects of UBB(+1) (e.g. kinase activation).
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Affiliation(s)
- Paula van Tijn
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
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50
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Lim KL, Ng XH, Grace LGY, Yao TP. Mitochondrial dynamics and Parkinson's disease: focus on parkin. Antioxid Redox Signal 2012; 16:935-49. [PMID: 21668405 PMCID: PMC3292756 DOI: 10.1089/ars.2011.4105] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
SIGNIFICANCE Parkinson's disease (PD) is a prevalent neurodegenerative disease affecting millions of individuals worldwide. Despite intensive efforts devoted to drug discovery, the disease remains incurable. To provide more effective medical therapy for PD, better understanding of the underlying causes of the disease is clearly necessary. RECENT ADVANCES A broad range of studies conducted over the past few decades have collectively implicated aberrant mitochondrial homeostasis as a key contributor to the development of PD. Supporting this, mutations in several PD-linked genes are directly or indirectly linked to mitochondrial dysfunction. In particular, recent discoveries have identified parkin, whose mutations are causative of recessive parkinsonism, as a key regulator of mitochondrial homeostasis. CRITICAL ISSUES Parkin appears to be involved in the entire spectrum of mitochondrial dynamics, including organelle biogenesis, fusion/fission, and clearance via mitophagy. How a single protein can regulate such diverse mitochondrial events is as intriguing as it is amazing; the mechanism underlying this is currently under intense research. Here, we provide an overview of mitochondrial dynamics and its relationship with neurodegenerative diseases and discuss current evidence and controversies surrounding the role of parkin in mitochondrial quality control and its relevance to PD pathogenesis. FUTURE DIRECTIONS Although the emerging field of parkin-mediated mitochondrial quality control has proven to be exciting, it is important to recognize that PD pathogenesis is likely to involve an intricate network of interacting pathways. Elucidating the reciprocity of pathways, particularly how other PD-related pathways potentially influence mitochondrial homeostasis, may hold the key to therapeutic development.
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Affiliation(s)
- Kah-Leong Lim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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