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Elabd S, Pauletto E, Solozobova V, Eickhoff N, Padrao N, Zwart W, Blattner C. TRIM25 targets p300 for degradation. Life Sci Alliance 2023; 6:e202301980. [PMID: 37770115 PMCID: PMC10539465 DOI: 10.26508/lsa.202301980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 10/01/2023] Open
Abstract
p300 is an important transcriptional co-factor. By stimulating the transfer of acetyl residues onto histones and several key transcription factors, p300 enhances transcriptional initiation and impacts cellular processes including cell proliferation and cell division. Despite its importance for cellular homeostasis, its regulation is poorly understood. We show that TRIM25, a member of the TRIM protein family, targets p300 for proteasomal degradation. However, despite TRIM25's RING domain and E3 activity, degradation of p300 by TRIM25 is independent of TRIM25-mediated p300 ubiquitination. Instead, TRIM25 promotes the interaction of p300 with dynein, which ensures a microtubule-dependent transport of p300 to cellular proteasomes. Through mediating p300 degradation, TRIM25 affects p300-dependent gene expression.
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Affiliation(s)
- Seham Elabd
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
- https://ror.org/00mzz1w90 Human Physiology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Eleonora Pauletto
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
| | - Valeria Solozobova
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
| | - Nils Eickhoff
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Nuno Padrao
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Wilbert Zwart
- Division of Oncogenomics, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Christine Blattner
- Institute for Biological and Chemical Systems - Biological Information Processing, Karlsruhe, Germany
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2
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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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3
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Cabrera-Rodríguez R, Pérez-Yanes S, Estévez-Herrera J, Márquez-Arce D, Cabrera C, Espert L, Blanco J, Valenzuela-Fernández A. The Interplay of HIV and Autophagy in Early Infection. Front Microbiol 2021; 12:661446. [PMID: 33995324 PMCID: PMC8113651 DOI: 10.3389/fmicb.2021.661446] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/31/2021] [Indexed: 12/11/2022] Open
Abstract
HIV/AIDS is still a global threat despite the notable efforts made by the scientific and health communities to understand viral infection, to design new drugs or to improve existing ones, as well as to develop advanced therapies and vaccine designs for functional cure and viral eradication. The identification and analysis of HIV-1 positive individuals that naturally control viral replication in the absence of antiretroviral treatment has provided clues about cellular processes that could interact with viral proteins and RNA and define subsequent viral replication and clinical progression. This is the case of autophagy, a degradative process that not only maintains cell homeostasis by recycling misfolded/old cellular elements to obtain nutrients, but is also relevant in the innate and adaptive immunity against viruses, such as HIV-1. Several studies suggest that early steps of HIV-1 infection, such as virus binding to CD4 or membrane fusion, allow the virus to modulate autophagy pathways preparing cells to be permissive for viral infection. Confirming this interplay, strategies based on autophagy modulation are able to inhibit early steps of HIV-1 infection. Moreover, autophagy dysregulation in late steps of the HIV-1 replication cycle may promote autophagic cell-death of CD4+ T cells or control of HIV-1 latency, likely contributing to disease progression and HIV persistence in infected individuals. In this scenario, understanding the molecular mechanisms underlying HIV/autophagy interplay may contribute to the development of new strategies to control HIV-1 replication. Therefore, the aim of this review is to summarize the knowledge of the interplay between autophagy and the early events of HIV-1 infection, and how autophagy modulation could impair or benefit HIV-1 infection and persistence, impacting viral pathogenesis, immune control of viral replication, and clinical progression of HIV-1 infected patients.
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Affiliation(s)
- Romina Cabrera-Rodríguez
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, e IUETSPC de la Universidad de La Laguna, Campus de Ofra s/n, Tenerife, Spain
| | - Silvia Pérez-Yanes
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, e IUETSPC de la Universidad de La Laguna, Campus de Ofra s/n, Tenerife, Spain
| | - Judith Estévez-Herrera
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, e IUETSPC de la Universidad de La Laguna, Campus de Ofra s/n, Tenerife, Spain
| | - Daniel Márquez-Arce
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, e IUETSPC de la Universidad de La Laguna, Campus de Ofra s/n, Tenerife, Spain
| | - Cecilia Cabrera
- AIDS Research Institute IrsiCaixa, Institut de Recerca en Ciències de la Salut Germans Trias i Pujol (IGTP), Barcelona, Spain
| | - Lucile Espert
- Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - Julià Blanco
- AIDS Research Institute IrsiCaixa, Institut de Recerca en Ciències de la Salut Germans Trias i Pujol (IGTP), Barcelona, Spain.,Universitat de Vic-Central de Catalunya (UVIC-UCC), Catalonia, Spain
| | - Agustín Valenzuela-Fernández
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, e IUETSPC de la Universidad de La Laguna, Campus de Ofra s/n, Tenerife, Spain
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4
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Elmallah MIY, Micheau O. Epigenetic Regulation of TRAIL Signaling: Implication for Cancer Therapy. Cancers (Basel) 2019; 11:cancers11060850. [PMID: 31248188 PMCID: PMC6627638 DOI: 10.3390/cancers11060850] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 06/11/2019] [Accepted: 06/18/2019] [Indexed: 12/20/2022] Open
Abstract
One of the main characteristics of carcinogenesis relies on genetic alterations in DNA and epigenetic changes in histone and non-histone proteins. At the chromatin level, gene expression is tightly controlled by DNA methyl transferases, histone acetyltransferases (HATs), histone deacetylases (HDACs), and acetyl-binding proteins. In particular, the expression level and function of several tumor suppressor genes, or oncogenes such as c-Myc, p53 or TRAIL, have been found to be regulated by acetylation. For example, HATs are a group of enzymes, which are responsible for the acetylation of histone proteins, resulting in chromatin relaxation and transcriptional activation, whereas HDACs by deacetylating histones lead to chromatin compaction and the subsequent transcriptional repression of tumor suppressor genes. Direct acetylation of suppressor genes or oncogenes can affect their stability or function. Histone deacetylase inhibitors (HDACi) have thus been developed as a promising therapeutic target in oncology. While these inhibitors display anticancer properties in preclinical models, and despite the fact that some of them have been approved by the FDA, HDACi still have limited therapeutic efficacy in clinical terms. Nonetheless, combined with a wide range of structurally and functionally diverse chemical compounds or immune therapies, HDACi have been reported to work in synergy to induce tumor regression. In this review, the role of HDACs in cancer etiology and recent advances in the development of HDACi will be presented and put into perspective as potential drugs synergizing with TRAIL's pro-apoptotic potential.
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Affiliation(s)
- Mohammed I Y Elmallah
- INSERM, Université Bourgogne Franche-Comté, LNC UMR1231, F-21079 Dijon, France.
- Chemistry Department, Faculty of Science, Helwan University, Ain Helwan 11795 Cairo, Egypt.
| | - Olivier Micheau
- INSERM, Université Bourgogne Franche-Comté, LNC UMR1231, F-21079 Dijon, France.
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5
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Proteostasis regulation by the ubiquitin system. Essays Biochem 2016; 60:143-151. [DOI: 10.1042/ebc20160001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/29/2016] [Indexed: 12/14/2022]
Abstract
Cells have developed an evolutionary obligation to survey and maintain proteome fidelity and avoid the possible toxic consequences of protein misfolding and aggregation. Disturbances to protein homoeostasis (proteostasis) can result in severe cellular phenotypes and are closely linked with the accumulation of microscopically visible deposits of aggregated proteins. These include inclusion bodies found in AD (Alzheimer's disease), HD (Huntington's disease) and ALS (amyotrophic lateral sclerosis) patient neurons. Protein aggregation is intimately linked with the ubiquitin and ubiquitin-like post-translational modifier system, which manages cellular protein folding stress and promotes the restoration of proteostasis. This is achieved in large part through the action of the UPS (ubiquitin–proteasome system), which is responsible for directing the proteasomal destruction of misfolded and damaged proteins tagged with ubiquitin chains. There are other less well understood ways in which ubiquitin family members can help to maintain proteostasis that complement, but are independent of, the UPS. This article discusses our current understanding of how the ubiquitin family regulates the protein misfolding pathways that threaten proteome fidelity, and how this is achieved by the key players in this process.
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Dickinson M, Johnstone RW, Prince HM. Histone deacetylase inhibitors: potential targets responsible for their anti-cancer effect. Invest New Drugs 2010; 28 Suppl 1:S3-20. [PMID: 21161327 PMCID: PMC3003794 DOI: 10.1007/s10637-010-9596-y] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 11/12/2010] [Indexed: 12/19/2022]
Abstract
The histone deacetylase inhibitors (HDACi) have demonstrated anticancer efficacy across a range of malignancies, most impressively in the hematological cancers. It is uncertain whether this clinical efficacy is attributable predominantly to their ability to induce apoptosis and differentiation in the cancer cell, or to their ability to prime the cell to other pro-death stimuli such as those from the immune system. HDACi-induced apoptosis occurs through altered expression of genes encoding proteins in both intrinsic and extrinsic apoptotic pathways; through effects on the proteasome/aggresome systems; through the production of reactive oxygen species, possibly by directly inducing DNA damage; and through alterations in the tumor microenvironment. In addition HDACi increase the immunogenicity of tumor cells and modulate cytokine signaling and potentially T-cell polarization in ways that may contribute the anti-cancer effect in vivo. Here, we provide an overview of current thinking on the mechanisms of HDACi activity, with attention given to the hematological malignancies as well as scientific observations arising from the clinical trials. We also focus on the immune effects of these agents.
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Affiliation(s)
- Michael Dickinson
- Department of Haematology, Peter MacCallum Cancer Centre, St Andrew’s Place, East Melbourne, VIC 3002 Australia
- University of Melbourne, Melbourne, Australia
| | - Ricky W. Johnstone
- Department of Haematology, Peter MacCallum Cancer Centre, St Andrew’s Place, East Melbourne, VIC 3002 Australia
- University of Melbourne, Melbourne, Australia
| | - H. Miles Prince
- Department of Haematology, Peter MacCallum Cancer Centre, St Andrew’s Place, East Melbourne, VIC 3002 Australia
- University of Melbourne, Melbourne, Australia
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7
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Vural A, Oner S, An N, Simon V, Ma D, Blumer JB, Lanier SM. Distribution of activator of G-protein signaling 3 within the aggresomal pathway: role of specific residues in the tetratricopeptide repeat domain and differential regulation by the AGS3 binding partners Gi(alpha) and mammalian inscuteable. Mol Cell Biol 2010; 30:1528-40. [PMID: 20065032 PMCID: PMC2832490 DOI: 10.1128/mcb.01018-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 09/10/2009] [Accepted: 12/30/2009] [Indexed: 11/20/2022] Open
Abstract
AGS3, a receptor-independent activator of G-protein signaling, is involved in unexpected functional diversity for G-protein signaling systems. AGS3 has seven tetratricopeptide (TPR) motifs upstream of four G-protein regulatory (GPR) motifs that serve as docking sites for Gialpha-GDP. The positioning of AGS3 within the cell and the intramolecular dynamics between different domains of the proteins are likely key determinants of their ability to influence G-protein signaling. We report that AGS3 enters into the aggresome pathway and that distribution of the protein is regulated by the AGS3 binding partners Gialpha and mammalian Inscuteable (mInsc). Gialpha rescues AGS3 from the aggresome, whereas mInsc augments the aggresome-like distribution of AGS3. The distribution of AGS3 to the aggresome is dependent upon the TPR domain, and it is accelerated by disruption of the TPR organizational structure or introduction of a nonsynonymous single-nucleotide polymorphism. These data present AGS3, G-proteins, and mInsc as candidate proteins involved in regulating cellular stress associated with protein-processing pathologies.
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Affiliation(s)
- Ali Vural
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425, Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California 93106
| | - Sadik Oner
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425, Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California 93106
| | - Ningfei An
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425, Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California 93106
| | - Violaine Simon
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425, Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California 93106
| | - Dzwokai Ma
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425, Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California 93106
| | - Joe B. Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425, Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California 93106
| | - Stephen M. Lanier
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425, Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California 93106
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8
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Nedelsky NB, Todd PK, Taylor JP. Autophagy and the ubiquitin-proteasome system: collaborators in neuroprotection. Biochim Biophys Acta Mol Basis Dis 2008; 1782:691-9. [PMID: 18930136 DOI: 10.1016/j.bbadis.2008.10.002] [Citation(s) in RCA: 258] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 10/07/2008] [Accepted: 10/08/2008] [Indexed: 11/26/2022]
Abstract
Protein degradation is an essential cellular function that, when dysregulated or impaired, can lead to a wide variety of disease states. The two major intracellular protein degradation systems are the ubiquitin-proteasome system (UPS) and autophagy, a catabolic process that involves delivery of cellular components to the lysosome for degradation. While the UPS has garnered much attention as it relates to neurodegenerative disease, important links between autophagy and neurodegeneration have also become evident. Furthermore, recent studies have revealed interaction between the UPS and autophagy, suggesting a coordinated and complementary relationship between these degradation systems that becomes critical in times of cellular stress. Here we describe autophagy and review evidence implicating this system as an important player in the pathogenesis of neurodegenerative disease. We discuss the role of autophagy in neurodegeneration and review its neuroprotective functions as revealed by experimental manipulation in disease models. Finally, we explore potential parallels and connections between autophagy and the UPS, highlighting their collaborative roles in protecting against neurodegenerative disease.
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Affiliation(s)
- Natalia B Nedelsky
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Olzmann JA, Li L, Chin LS. Aggresome formation and neurodegenerative diseases: therapeutic implications. Curr Med Chem 2008; 15:47-60. [PMID: 18220762 DOI: 10.2174/092986708783330692] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Accumulation of misfolded proteins in proteinaceous inclusions is a prominent pathological feature common to many age-related neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis. In cultured cells, when the production of misfolded proteins exceeds the capacity of the chaperone refolding system and the ubiquitin-proteasome degradation pathway, misfolded proteins are actively transported to a cytoplasmic juxtanuclear structure called an aggresome. Aggresome formation is recognized as a cytoprotective response serving to sequester potentially toxic misfolded proteins and facilitate their clearance by autophagy. Recent evidence indicates that aggresome formation is mediated by dynein/dynactin-mediated microtubule-based transport of misfolded proteins to the centrosome and involves several regulators, including histone deacetylase 6, E3 ubiquitin-protein ligase parkin, deubiquitinating enzyme ataxin-3, and ubiquilin-1. Characterization of the molecular mechanisms underlying aggresome formation and its regulation has begun to provide promising therapeutic targets that may be relevant to neurodegenerative diseases. In this review, we provide an overview of the molecular machinery controlling aggresome formation and discuss potential useful compounds and intervention strategies for preventing or reducing the cytotoxicity of misfolded and aggregated proteins.
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Affiliation(s)
- J A Olzmann
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
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The heavy metal cadmium induces valosin-containing protein (VCP)-mediated aggresome formation. Toxicol Appl Pharmacol 2008; 228:351-63. [PMID: 18261755 DOI: 10.1016/j.taap.2007.12.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 12/10/2007] [Accepted: 12/19/2007] [Indexed: 11/20/2022]
Abstract
Cadmium (Cd2+) is a heavy metal ion known to have a long biological half-life in humans. Accumulating evidence shows that exposure to Cd2+ is associated with neurodegenerative diseases characterized by the retention of ubiquitinated and misfolded proteins in the lesions. Here, we report that Cd2+ directly induces the formation of protein inclusion bodies in cells. The protein inclusion body is an aggresome, a major organelle for collecting ubiquitinated or misfolded proteins. Our results show that aggresomes are enriched in the detergent-insoluble fraction of Cd2+-treated cell lysates. Proteomic analysis identified 145 proteins in the aggresome-enriched fractions. One of the proteins is the highly conserved valosin-containing protein (VCP), which has been shown to colocalize with aggresomes and bind ubiquitinated proteins through its N domain (#1-200). Our subsequent examination of VCP's role in the formation of aggresomes induced by Cd2+ indicates that the C-terminal tail (#780-806) of VCP interacts with histone deacetylase HDAC6, a mediator for aggresome formation, suggesting that VCP participates in transporting ubiquitinated proteins to aggresomes. This function of VCP is impaired by inhibition of the deacetylase activity of HDAC6 or by over-expression of VCP mutants that do not bind ubiquitinated proteins or HDAC6. Our results indicate that Cd2+ induces the formation of protein inclusion bodies by promoting the accumulation of ubiquitinated proteins in aggresomes through VCP and HDAC6. Our delineation of the role of VCP in regulating cell responses to ubiquitinated proteins has important implications for understanding Cd2+ toxicity and associated diseases.
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11
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Lee JH, Park JH, Jung Y, Kim JH, Jong HS, Kim TY, Bang YJ. Histone deacetylase inhibitor enhances 5-fluorouracil cytotoxicity by down-regulating thymidylate synthase in human cancer cells. Mol Cancer Ther 2007; 5:3085-95. [PMID: 17172411 DOI: 10.1158/1535-7163.mct-06-0419] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Thymidylate synthase (TS) overexpression is a key determinant of 5-fluorouracil (5-FU) resistance in human cancer cells. TS is also acutely up-regulated with 5-FU treatment, and, thus, novel strategies targeting TS down-regulation seem to be promising in terms of modulating 5-FU resistance. Here, we report that histone deacetylase inhibitors can reverse 5-FU resistance by down-regulating TS. By using cDNA microarrays and validation experiments, we found that trichostatin A reduced the expression of both TS mRNA and TS protein. Cotreatment with trichostatin A and cycloheximide restored TS mRNA expression, suggesting that TS mRNA is repressed through new protein synthesis. On the other hand, TS protein expression was significantly reduced by lower doses of trichostatin A (50 nmol/L). Mechanistically, TS protein was found to interact with heat shock protein (Hsp) complex, and trichostatin A treatment induced chaperonic Hsp90 acetylation and subsequently enhanced Hsp70 binding to TS, which led to the proteasomal degradation of TS protein. Of note, combined treatment with low-dose trichostatin A and 5-FU enhanced 5-FU-mediated cytotoxicity in 5-FU-resistant cancer cells in accordance with TS protein down-regulation. We conclude that a combinatorial approach using histone deacetylase inhibitors may be useful at overcoming 5-FU resistance.
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Affiliation(s)
- Ju-Hee Lee
- Natonal Research Laboratory, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul 110-744, Korea
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12
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Iwata A, Riley BE, Johnston JA, Kopito RR. HDAC6 and microtubules are required for autophagic degradation of aggregated huntingtin. J Biol Chem 2005; 280:40282-92. [PMID: 16192271 DOI: 10.1074/jbc.m508786200] [Citation(s) in RCA: 563] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CNS neurons are endowed with the ability to recover from cytotoxic insults associated with the accumulation of proteinaceous polyglutamine aggregates via a process that appears to involve capture and degradation of aggregates by autophagy. The ubiquitin-proteasome system protects cells against proteotoxicity by degrading soluble monomeric misfolded aggregation-prone proteins but is ineffective against, and impaired by, non-native protein oligomers. Here we show that autophagy is induced in response to impaired ubiquitin proteasome system activity. We show that ATG proteins, molecular determinants of autophagic vacuole formation, and lysosomes are recruited to pericentriolar cytoplasmic inclusion bodies by a process requiring an intact microtubule cytoskeleton and the cytoplasmic deacetylase HDAC6. These data suggest that HDAC6-dependent retrograde transport on microtubules is used by cells to increase the efficiency and selectivity of autophagic degradation.
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Affiliation(s)
- Atsushi Iwata
- Department of Biological Sciences, BIO-X Program, Stanford University, Stanford, California 94305-5430, USA
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13
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Abstract
Dynactin is a multisubunit protein complex that is required for most, if not all, types of cytoplasmic dynein activity in eukaryotes. Dynactin binds dynein directly and allows the motor to traverse the microtubule lattice over long distances. A single dynactin subunit, p150Glued, is sufficient for both activities, yet dynactin contains several other subunits that are organized into an elaborate structure. It is currently believed that the bulk of the dynactin structure participates in interactions with a wide range of cellular structures, many of which are cargoes of the dynein motor. Genetic studies verify the importance of all elements of dynactin structure to its function. Although dynein can bind some membranous cargoes independently of dynactin, establishment of a fully functional dynein-cargo link appears to depend on dynactin. In this review, I summarize what is presently known about dynactin structure, the cellular structures with which it associates, and the intermolecular interactions that underlie and regulate binding. Although the molecular details of dynactin's interactions with membranous organelles and other molecules are complex, the framework provided here is intended to distill what is presently known and to be of use to dynactin specialists and beginners alike.
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Affiliation(s)
- Trina A Schroer
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
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14
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Lagace DC, Timothy O'Brien W, Gurvich N, Nachtigal MW, Klein PS. Valproic acid: how it works. Or not. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.cnr.2004.09.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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