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George DE, Tepe JJ. Advances in Proteasome Enhancement by Small Molecules. Biomolecules 2021; 11:1789. [PMID: 34944433 PMCID: PMC8699248 DOI: 10.3390/biom11121789] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/23/2021] [Accepted: 11/26/2021] [Indexed: 01/11/2023] Open
Abstract
The proteasome system is a large and complex molecular machinery responsible for the degradation of misfolded, damaged, and redundant cellular proteins. When proteasome function is impaired, unwanted proteins accumulate, which can lead to several diseases including age-related and neurodegenerative diseases. Enhancing proteasome-mediated substrate degradation with small molecules may therefore be a valuable strategy for the treatment of various neurodegenerative diseases such as Parkinson's, Alzheimer's, and Huntington's diseases. In this review, we discuss the structure of proteasome and how proteasome's proteolytic activity is associated with aging and various neurodegenerative diseases. We also summarize various classes of compounds that are capable of enhancing, directly or indirectly, proteasome-mediated protein degradation.
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Affiliation(s)
| | - Jetze J. Tepe
- Department of Chemistry and Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA;
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2
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Reboud-Ravaux M. [The proteasome - structural aspects and inhibitors: a second life for a validated drug target]. Biol Aujourdhui 2021; 215:1-23. [PMID: 34397372 DOI: 10.1051/jbio/2021005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Indexed: 02/06/2023]
Abstract
The proteasome is the central component of the adaptable ubiquitin proteasome system (UPS) discovered in the 1980's. It sustains protein homeostasis (proteostasis) under a large variety of physiological and pathological conditions. Its dysregulation has been often associated to various human diseases. Its potential regulation by modulators has emerged as promising avenue to develop treatments of various pathologies. The FDA approval in 2003 of the proteasome inhibitor bortezomib to treat multiple myeloma, then mantle lymphoma in 2006, has considerably increased the clinical interest of proteasome inhibition. Second-generation proteasome inhibitors (carfilzomib and ixazomib) have been approved to overcome bortezomib resistance and improved toxicity profile and route of administration. Selective inhibition of immunoproteasome is a promising approach towards the development of immunomodulatory drugs. The design of these drugs relies greatly on the elucidation of high-resolution structures of the targeted proteasomes. The ATPase-dependent 26S proteasome (2.4 MDa) consists of a 20S proteolytic core and one or two 19S regulatory particles. The 20S core contains three types of catalytic sites. In recent years, due to technical advances especially in atomic cryo-electron microscopy, significant progress has been made in the understanding of 26S proteasome structure and its dynamics. Stepwise conformational changes of the 19S particle induced by ATP hydrolysis lead to substrate translocation, 20S pore opening and processive protein degradation by the 20S proteolytic subunits (2β1, 2β2 and 2β5). A large variety of structurally different inhibitors, both natural products or synthetic compounds targeting immuno- and constitutive proteasomes, has been discovered. The latest advances in this drug discovery are presented. Knowledge about structures, inhibition mechanism and detailed biological regulations of proteasomes can guide strategies for the development of next-generation inhibitors to treat human diseases, especially cancers, immune disorders and pathogen infections. Proteasome activators are also potentially applicable to the reduction of proteotoxic stresses in neurodegeneration and aging.
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Affiliation(s)
- Michèle Reboud-Ravaux
- Sorbonne Université, Institut de Biologie Paris Seine (IBPS), CNRS UMR 8256, Inserm ERL U1164, 7 quai Saint Bernard, 75252 Paris Cedex 05, France
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3
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Mladenovic Djordjevic AN, Kapetanou M, Loncarevic-Vasiljkovic N, Todorovic S, Athanasopoulou S, Jovic M, Prvulovic M, Taoufik E, Matsas R, Kanazir S, Gonos ES. Pharmacological intervention in a transgenic mouse model improves Alzheimer's-associated pathological phenotype: Involvement of proteasome activation. Free Radic Biol Med 2021; 162:88-103. [PMID: 33279620 PMCID: PMC7889698 DOI: 10.1016/j.freeradbiomed.2020.11.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/23/2020] [Accepted: 11/28/2020] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia worldwide, characterized by a progressive decline in a variety of cognitive and non-cognitive functions. The amyloid beta protein cascade hypothesis places the formation of amyloid beta protein aggregates on the first position in the complex pathological cascade leading to neurodegeneration, and therefore AD might be considered to be a protein-misfolding disease. The Ubiquitin Proteasome System (UPS), being the primary protein degradation mechanism with a fundamental role in the maintenance of proteostasis, has been identified as a putative therapeutic target to delay and/or to decelerate the progression of neurodegenerative disorders that are characterized by accumulated/aggregated proteins. The purpose of this study was to test if the activation of proteasome in vivo can alleviate AD pathology. Specifically by using two compounds with complementary modes of proteasome activation and documented antioxidant and redox regulating properties in the 5xFAD transgenic mice model of AD, we ameliorated a number of AD related deficits. Shortly after proteasome activation we detected significantly reduced amyloid-beta load correlated with improved motor functions, reduced anxiety and frailty level. Essentially, to our knowledge this is the first report to demonstrate a dual activation of the proteasome and its downstream effects. In conclusion, these findings open up new directions for future therapeutic potential of proteasome-mediated proteolysis enhancement.
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Affiliation(s)
- Aleksandra N Mladenovic Djordjevic
- Department for Neurobiology, Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Boulevard Despota Stefana, 142, 11000, Belgrade, Serbia.
| | - Marianna Kapetanou
- Institute of Chemical Biology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635, Athens, Greece
| | - Natasa Loncarevic-Vasiljkovic
- Department for Neurobiology, Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Boulevard Despota Stefana, 142, 11000, Belgrade, Serbia; Molecular Nutrition and Health Lab, CEDOC - Centro de Estudos de Doenças Crónicas, NOVA Medical School / Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Edifício CEDOC II, Rua Câmara Pestana 6, 1150-082, Lisboa, Portugal
| | - Smilja Todorovic
- Department for Neurobiology, Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Boulevard Despota Stefana, 142, 11000, Belgrade, Serbia
| | - Sofia Athanasopoulou
- Institute of Chemical Biology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635, Athens, Greece; Department of Biology, Faculty of Medicine, University of Thessaly, Biopolis, 41500, Larissa, Greece
| | - Milena Jovic
- Department for Neurobiology, Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Boulevard Despota Stefana, 142, 11000, Belgrade, Serbia
| | - Milica Prvulovic
- Department for Neurobiology, Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Boulevard Despota Stefana, 142, 11000, Belgrade, Serbia
| | - Era Taoufik
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue, 11521, Athens, Greece
| | - Rebecca Matsas
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue, 11521, Athens, Greece
| | - Selma Kanazir
- Department for Neurobiology, Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Boulevard Despota Stefana, 142, 11000, Belgrade, Serbia
| | - Efstathios S Gonos
- Institute of Chemical Biology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635, Athens, Greece.
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4
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Hubbell GE, Tepe JJ. Natural product scaffolds as inspiration for the design and synthesis of 20S human proteasome inhibitors. RSC Chem Biol 2020; 1:305-332. [PMID: 33791679 PMCID: PMC8009326 DOI: 10.1039/d0cb00111b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022] Open
Abstract
The 20S proteasome is a valuable target for the treatment of a number of diseases including cancer, neurodegenerative disease, and parasitic infection. In an effort to discover novel inhibitors of the 20S proteasome, many reseaarchers have looked to natural products as potential leads for drug discovery. The following review discusses the efforts made in the field to isolate and identify natural products as inhibitors of the proteasome. In addition, we describe some of the modifications made to natural products in order to discover more potent and selective inhibitors for potential disease treatment.
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Affiliation(s)
- Grace E. Hubbell
- Department of Chemistry, Michigan State UniversityEast LansingMI 48823USA
| | - Jetze J. Tepe
- Department of Chemistry, Michigan State UniversityEast LansingMI 48823USA
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5
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Proteasome Inhibitors: Harnessing Proteostasis to Combat Disease. Molecules 2020; 25:molecules25030671. [PMID: 32033280 PMCID: PMC7037493 DOI: 10.3390/molecules25030671] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/25/2020] [Accepted: 01/28/2020] [Indexed: 02/07/2023] Open
Abstract
The proteasome is the central component of the main cellular protein degradation pathway. During the past four decades, the critical function of the proteasome in numerous physiological processes has been revealed, and proteasome activity has been linked to various human diseases. The proteasome prevents the accumulation of misfolded proteins, controls the cell cycle, and regulates the immune response, to name a few important roles for this macromolecular "machine." As a therapeutic target, proteasome inhibitors have been approved for the treatment of multiple myeloma and mantle cell lymphoma. However, inability to sufficiently inhibit proteasome activity at tolerated doses has hampered efforts to expand the scope of proteasome inhibitor-based therapies. With emerging new modalities in myeloma, it might seem challenging to develop additional proteasome-based therapies. However, the constant development of new applications for proteasome inhibitors and deeper insights into the intricacies of protein homeostasis suggest that proteasome inhibitors might have novel therapeutic applications. Herein, we summarize the latest advances in proteasome inhibitor development and discuss the future of proteasome inhibitors and other proteasome-based therapies in combating human diseases.
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Coux O, Zieba BA, Meiners S. The Proteasome System in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:55-100. [DOI: 10.1007/978-3-030-38266-7_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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7
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Abstract
Proteasomes are multienzyme complexes that maintain protein homeostasis (proteostasis) and important cellular functions through the degradation of misfolded, redundant, and damaged proteins. It is well established that aging is associated with the accumulation of damaged and misfolded proteins. This phenomenon is paralleled by declined proteasome activity. When the accumulation of redundant proteins exceed degradation, undesirable signaling and/or aggregation occurs and are the hallmarks of neurodegenerative diseases and many cancers. Thus, increasing proteasome activity has been recognized as a new approach to delay the onset or ameliorate the symptoms of neurodegenerative and other proteotoxic disorders. Enhancement of proteasome activity has many therapeutic potentials but is still a relatively unexplored field. In this perspective, we review current approaches, genetic manipulation, posttranslational modification, and small molecule proteasome agonists used to increase proteasome activity, challenges facing the field, and applications beyond aging and neurodegenerative diseases.
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Affiliation(s)
- Evert Njomen
- Department of Chemistry, and Pharmacology & Toxicology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jetze J. Tepe
- Department of Chemistry, and Pharmacology & Toxicology, Michigan State University, East Lansing, Michigan 48824, United States
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8
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Razzaq A, Shamsi S, Ali A, Ali Q, Sajjad M, Malik A, Ashraf M. Microbial Proteases Applications. Front Bioeng Biotechnol 2019; 7:110. [PMID: 31263696 PMCID: PMC6584820 DOI: 10.3389/fbioe.2019.00110] [Citation(s) in RCA: 190] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/01/2019] [Indexed: 11/13/2022] Open
Abstract
The use of chemicals around the globe in different industries has increased tremendously, affecting the health of people. The modern world intends to replace these noxious chemicals with environmental friendly products for the betterment of life on the planet. Establishing enzymatic processes in spite of chemical processes has been a prime objective of scientists. Various enzymes, specifically microbial proteases, are the most essentially used in different corporate sectors, such as textile, detergent, leather, feed, waste, and others. Proteases with respect to physiological and commercial roles hold a pivotal position. As they are performing synthetic and degradative functions, proteases are found ubiquitously, such as in plants, animals, and microbes. Among different producers of proteases, Bacillus sp. are mostly commercially exploited microbes for proteases. Proteases are successfully considered as an alternative to chemicals and an eco-friendly indicator for nature or the surroundings. The evolutionary relationship among acidic, neutral, and alkaline proteases has been analyzed based on their protein sequences, but there remains a lack of information that regulates the diversity in their specificity. Researchers are looking for microbial proteases as they can tolerate harsh conditions, ways to prevent autoproteolytic activity, stability in optimum pH, and substrate specificity. The current review focuses on the comparison among different proteases and the current problems faced during production and application at the industrial level. Deciphering these issues would enable us to promote microbial proteases economically and commercially around the world.
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Affiliation(s)
- Abdul Razzaq
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Sadia Shamsi
- School of Medicine, Medical Sciences and Nutrition, The Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Arfan Ali
- 1-FB, Genetics, Four Brothers Group, Lahore, Pakistan
| | - Qurban Ali
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Muhammad Sajjad
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Arif Malik
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Muhammad Ashraf
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
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9
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Abstract
The ubiquitin proteasome system (UPS) degrades individual proteins in a highly regulated fashion and is responsible for the degradation of misfolded, damaged, or unneeded cellular proteins. During the past 20 years, investigators have established a critical role for the UPS in essentially every cellular process, including cell cycle progression, transcriptional regulation, genome integrity, apoptosis, immune responses, and neuronal plasticity. At the center of the UPS is the proteasome, a large and complex molecular machine containing a multicatalytic protease complex. When the efficiency of this proteostasis system is perturbed, misfolded and damaged protein aggregates can accumulate to toxic levels and cause neuronal dysfunction, which may underlie many neurodegenerative diseases. In addition, many cancers rely on robust proteasome activity for degrading tumor suppressors and cell cycle checkpoint inhibitors necessary for rapid cell division. Thus, proteasome inhibitors have proven clinically useful to treat some types of cancer, especially multiple myeloma. Numerous cellular processes rely on finely tuned proteasome function, making it a crucial target for future therapeutic intervention in many diseases, including neurodegenerative diseases, cystic fibrosis, atherosclerosis, autoimmune diseases, diabetes, and cancer. In this review, we discuss the structure and function of the proteasome, the mechanisms of action of different proteasome inhibitors, various techniques to evaluate proteasome function in vitro and in vivo, proteasome inhibitors in preclinical and clinical development, and the feasibility for pharmacological activation of the proteasome to potentially treat neurodegenerative disease.
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Affiliation(s)
- Tiffany A Thibaudeau
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
| | - David M Smith
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
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10
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Yedidi RS, Fatehi AK, Enenkel C. Proteasome dynamics between proliferation and quiescence stages of Saccharomyces cerevisiae. Crit Rev Biochem Mol Biol 2016; 51:497-512. [PMID: 27677933 DOI: 10.1080/10409238.2016.1230087] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The ubiquitin-proteasome system (UPS) plays a critical role in cellular protein homeostasis and is required for the turnover of short-lived and unwanted proteins, which are targeted by poly-ubiquitination for degradation. Proteasome is the key protease of UPS and consists of multiple subunits, which are organized into a catalytic core particle (CP) and a regulatory particle (RP). In Saccharomyces cerevisiae, proteasome holo-enzymes are engaged in degrading poly-ubiquitinated substrates and are mostly localized in the nucleus during cell proliferation. While in quiescence, the RP and CP are sequestered into motile and reversible storage granules in the cytoplasm, called proteasome storage granules (PSGs). The reversible nature of PSGs allows the proteasomes to be transported back into the nucleus upon exit from quiescence. Nuclear import of RP and CP through nuclear pores occurs via the canonical pathway that includes the importin-αβ heterodimer and takes advantage of the Ran-GTP gradient across the nuclear membrane. Dependent on the growth stage, either inactive precursor complexes or mature holo-enzymes are imported into the nucleus. The present review discusses the dynamics of proteasomes including their assembly, nucleo-cytoplasmic transport during proliferation and the sequestration of proteasomes into PSGs during quiescence. [Formula: see text].
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Affiliation(s)
| | | | - Cordula Enenkel
- a Department of Biochemistry , University of Toronto , Toronto , Canada
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11
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Arnold SA, Albiez S, Opara N, Chami M, Schmidli C, Bieri A, Padeste C, Stahlberg H, Braun T. Total Sample Conditioning and Preparation of Nanoliter Volumes for Electron Microscopy. ACS NANO 2016; 10:4981-4988. [PMID: 27074622 DOI: 10.1021/acsnano.6b01328] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electron microscopy (EM) entered a new era with the emergence of direct electron detectors and new nanocrystal electron diffraction methods. However, sample preparation techniques have not progressed and still suffer from extensive blotting steps leading to a massive loss of sample. Here, we present a simple but versatile method for the almost lossless sample conditioning and preparation of nanoliter volumes of biological samples for EM, keeping the sample under close to physiological condition. A microcapillary is used to aspirate 3-5 nL of sample. The microcapillary tip is immersed into a reservoir of negative stain or trehalose, where the sample becomes conditioned by diffusive exchange of salt and heavy metal ions or sugar molecules, respectively, before it is deposited as a small spot onto an EM grid. We demonstrate the use of the method to prepare protein particles for imaging by transmission EM and nanocrystals for analysis by electron diffraction. Furthermore, the minute sample volume required for this method enables alternative strategies for biological experiments, such as the analysis of the content of a single cell by visual proteomics, fully exploiting the single molecule detection limit of EM.
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Affiliation(s)
| | | | - Nadia Opara
- Paul Scherrer Institute (PSI) , 5232 Villigen, Switzerland
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12
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Mammalian proteasome subtypes: Their diversity in structure and function. Arch Biochem Biophys 2015; 591:132-40. [PMID: 26724758 DOI: 10.1016/j.abb.2015.12.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 12/22/2015] [Indexed: 11/21/2022]
Abstract
The 20S proteasome is a multicatalytic proteinase catalysing the degradation of the majority of intracellular proteins. Thereby it is involved in almost all basic cellular processes, which is facilitated by its association with various regulator complexes so that it appears in different disguises like 26S proteasome, hybrid-proteasome and others. The 20S proteasome has a cylindrical structure built up by four stacked rings composed of α- and β-subunits. Since the three active site-containing β-subunits can all or in part be replaced by immuno-subunits, three main subpopulations exist, namely standard-, immuno- and intermediate-proteasomes. Due to posttranslational modifications or/and genetic variations all α- and β-subunits occur in multiple iso- or proteoforms. This leads to the fact that each of the three subpopulations is composed of a variety of 20S proteasome subtypes. This review summarizes the knowledge of proteasome subtypes in mammalian cells and tissues and their possible biological and medical relevancy.
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13
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Satoh T, Saeki Y, Hiromoto T, Wang YH, Uekusa Y, Yagi H, Yoshihara H, Yagi-Utsumi M, Mizushima T, Tanaka K, Kato K. Structural basis for proteasome formation controlled by an assembly chaperone nas2. Structure 2014; 22:731-43. [PMID: 24685148 DOI: 10.1016/j.str.2014.02.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/30/2014] [Accepted: 02/21/2014] [Indexed: 11/18/2022]
Abstract
Proteasome formation does not occur due to spontaneous self-organization but results from a highly ordered process assisted by several assembly chaperones. The assembly of the proteasome ATPase subunits is assisted by four client-specific chaperones, of which three have been structurally resolved. Here, we provide the structural basis for the working mechanisms of the last, hereto structurally uncharacterized assembly chaperone, Nas2. We revealed that Nas2 binds to the Rpt5 subunit in a bivalent mode: the N-terminal helical domain of Nas2 masks the Rpt1-interacting surface of Rpt5, whereas its C-terminal PDZ domain caps the C-terminal proteasome-activating motif. Thus, Nas2 operates as a proteasome activation blocker, offering a checkpoint during the formation of the 19S ATPase prior to its docking onto the proteolytic 20S core particle.
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Affiliation(s)
- Tadashi Satoh
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; JST, PRESTO, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Yasushi Saeki
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Takeshi Hiromoto
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Ying-Hui Wang
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Yoshinori Uekusa
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Hirokazu Yagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Hidehito Yoshihara
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Maho Yagi-Utsumi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Tsunehiro Mizushima
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; Picobiology Institute, Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Keiji Tanaka
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
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14
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Kabani M, Redeker V, Melki R. A role for the proteasome in the turnover of Sup35p and in [PSI(+) ] prion propagation. Mol Microbiol 2014; 92:507-28. [PMID: 24589377 DOI: 10.1111/mmi.12572] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2014] [Indexed: 01/21/2023]
Abstract
Yeast prions are superb models for understanding the mechanisms of self-perpetuating protein aggregates formation. [PSI(+) ] stands among the most documented yeast prions and results from self-assembly of the translation termination factor Sup35p into protein fibrils. A plethora of cellular factors were shown to affect [PSI(+) ] formation and propagation. Clearance of Sup35p prion particles is however poorly understood and documented. Here, we investigated the role of the proteasome in the degradation of Sup35p and in [PSI(+) ] prion propagation. We found that cells lacking the RPN4 gene, which have reduced intracellular proteasome pools, accumulated Sup35p and have defects in [PSI(+) ] formation and propagation. Sup35p is degraded in vitro by the 26S and 20S proteasomes in a ubiquitin-independent manner, generating an array of amyloidogenic peptides derived from its prion-domain. We also demonstrate the formation of a proteasome-resistant fragment spanning residues 83-685 which is devoid of the prion-domain that is essential for [PSI(+) ] propagation. Most important was the finding that the 26S and 20S proteasomes degrade Sup35p fibrils in vitro and abolish their infectivity. Our results point to an overlooked role of the proteasome in clearing toxic protein aggregates, and have important implications for a better understanding of the life cycle of infectious protein assemblies.
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Affiliation(s)
- Mehdi Kabani
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Bât. 34, Avenue de la Terrasse, F-91190, Gif-sur-Yvette, France
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15
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Degradation of M(r) 25,000 protein by cathepsin L-like protease in Xenopus laevis oocytes. Protein J 2014; 33:150-6. [PMID: 24510540 DOI: 10.1007/s10930-014-9542-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A phosphorylated protein with a molecular mass of 25,000 (pp25) is involved in Xenopus laevis vitellogenin B1 and partially overlaps with phosvitin and lipovitellin 2. The protease responsible for pp25 degradation was studied in vitro since this occurs during embryogenesis. Initially, a protease thought to be a contaminant of the purified pp25 preparation was analyzed and an antipain-sensitive protease presumed to be involved. When commercially available proteases were examined, pp25 was not degraded by calpain I or 20S proteasome, but it was degraded by cathepsin L in vitro. A survey of the protease responsible for pp25 degradation in the cytoplasm of Xenopus oocytes found partially purified pp25 was degraded in partly antipain-sensitive manner. These results suggest that an antipain-sensitive protease or cathepsin L (or a related protease) is a candidate for pp25 degradation.
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16
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Souza LDC, Camargo R, Demasi M, Santana JM, de Sá CM, de Freitas SM. Effects of an anticarcinogenic Bowman-Birk protease inhibitor on purified 20S proteasome and MCF-7 breast cancer cells. PLoS One 2014; 9:e86600. [PMID: 24475156 PMCID: PMC3903573 DOI: 10.1371/journal.pone.0086600] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/11/2013] [Indexed: 01/01/2023] Open
Abstract
Proteasome inhibitors have been described as an important target for cancer therapy due to their potential to regulate the ubiquitin-proteasome system in the degradation pathway of cellular proteins. Here, we reported the effects of a Bowman-Birk-type protease inhibitor, the Black-eyed pea Trypsin/Chymotrypsin Inhibitor (BTCI), on proteasome 20S in MCF-7 breast cancer cells and on catalytic activity of the purified 20S proteasome from horse erythrocytes, as well as the structural analysis of the BTCI-20S proteasome complex. In vitro experiments and confocal microscopy showed that BTCI readily crosses the membrane of the breast cancer cells and co-localizes with the proteasome in cytoplasm and mainly in nucleus. Indeed, as indicated by dynamic light scattering, BTCI and 20S proteasome form a stable complex at temperatures up to 55°C and at neutral and alkaline pHs. In complexed form, BTCI strongly inhibits the proteolytic chymotrypsin-, trypsin- and caspase-like activities of 20S proteasome, indicated by inhibition constants of 10−7 M magnitude order. Besides other mechanisms, this feature can be associated with previously reported cytostatic and cytotoxic effects of BTCI in MCF-7 breast cancer cells by means of apoptosis.
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Affiliation(s)
- Larissa da Costa Souza
- Laboratory of Biophysics, Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Ricardo Camargo
- Laboratory of Microbiology Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Marilene Demasi
- Laboratory of Biochemistry and Biophysics, Butantan Institute, São Paulo, Brazil
| | - Jaime Martins Santana
- Laboratory of Pathogen-Host Interface, Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Cézar Martins de Sá
- Laboratory of Microbiology Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Sonia Maria de Freitas
- Laboratory of Biophysics, Department of Cellular Biology, University of Brasília, Brasília, Brazil
- * E-mail:
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17
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Koohmaraie M. Biochemical factors regulating the toughening and tenderization processes of meat. Meat Sci 2013; 43S1:193-201. [PMID: 22060651 DOI: 10.1016/0309-1740(96)00065-4] [Citation(s) in RCA: 373] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The purpose of this manuscript is to present a brief review of the biochemical basis for longissimus toughening and tenderization processes. Also, to explore the potential technologies that can be developed based on this knowledge to reduce variation in tenderness, thus, improving consumer acceptance of meat. Results suggest that after slaughter longissimus has low to intermediate shear force values (probably tender). Rigor development-induced changes increase its shear force. Maximum toughness is observed between 12 to 24 h post mortem. The toughening process seems to occur equally in all carcasses. Post-mortem storage at refrigerated conditions tenderizes longissimus. Post-mortem tenderization is caused by enzymatic degradation of key myofibrillar and associated proteins. The function of these proteins is to maintain the structural integrity of myofibrils. Current data indicates that μ-calpain is responsible for degradation of these proteins. Unlike the toughening process, there exists a large variation in the rate and extent of tenderization which is responsible for variation in tenderness at the consumer level. Potential strategies for the control of the variation in meat tenderness are discussed.
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Affiliation(s)
- M Koohmaraie
- USDA-ARS, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, Nebraska, USA
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18
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Dechavanne V, Vilbois F, Glez L, Antonsson B. Purification and separation of the 20S immunoproteasome from the constitutive proteasome and identification of the subunits by LC–MS. Protein Expr Purif 2013; 87:100-10. [DOI: 10.1016/j.pep.2012.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 10/29/2012] [Accepted: 10/31/2012] [Indexed: 10/27/2022]
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19
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Takagi K, Kim S, Yukii H, Ueno M, Morishita R, Endo Y, Kato K, Tanaka K, Saeki Y, Mizushima T. Structural basis for specific recognition of Rpt1p, an ATPase subunit of 26 S proteasome, by proteasome-dedicated chaperone Hsm3p. J Biol Chem 2012; 287:12172-82. [PMID: 22334676 DOI: 10.1074/jbc.m112.345876] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The 26 S proteasome is a 2.5-MDa molecular machine that degrades ubiquitinated proteins in eukaryotic cells. It consists of a proteolytic core particle and two 19 S regulatory particles (RPs) composed of 6 ATPase (Rpt) and 13 non-ATPase (Rpn) subunits. Multiple proteasome-dedicated chaperones facilitate the assembly of the proteasome, but little is known about the detailed mechanisms. Hsm3, a 19 S RP dedicated chaperone, transiently binds to the C-terminal domain of the Rpt1 subunit and forms a tetrameric complex, Hsm3-Rpt1-Rpt2-Rpn1, during maturation of the ATPase ring of 19 S RP. To elucidate the structural basis of Hsm3 function, we determined the crystal structures of Hsm3 and its complex with the C-terminal domain of the Rpt1 subunit (Rpt1C). Hsm3 has a C-shaped structure that consists of 11 HEAT repeats. The structure of the Hsm3-Rpt1C complex revealed that the interacting surface between Hsm3 and Rpt1 is a hydrophobic core and a complementary charged surface. Mutations in the Hsm3-Rpt1 surface resulted in the assembly defect of the 26 S proteasome. Furthermore, a structural model of the Hsm3-Rpt ring complex and an in vitro binding assay suggest that Hsm3 can bind Rpt2 in addition to Rpt1. Collectively, our results provide the structural basis of the molecular functions of Hsm3 for the RP assembly.
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Affiliation(s)
- Kenji Takagi
- Picobiology Institute, Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1, Kouto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan
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20
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Beyer NH, Milthers J, Bonde Lauridsen AM, Houen G, Lautrup Frederiksen J. Autoantibodies to the proteasome in monosymptomatic optic neuritis may predict progression to multiple sclerosis. Scandinavian Journal of Clinical and Laboratory Investigation 2009; 67:696-706. [PMID: 17852796 DOI: 10.1080/00365510701342062] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Proteasome autoantibodies (PAB) have been found in multiple sclerosis (MS) patient sera and cerebrospinal fluid (CSF). Presence of PAB could thus be a possible diagnostic marker for MS. We investigated whether PAB serum status in acute monosymptomatic optic neuritis (ON) and MS differed significantly from that of healthy controls, and whether or not PAB status is predictive of later MS development in patients with ON. MATERIAL AND METHODS Sera from ON patients, MS patients and healthy donors were analysed retrospectively using ELISA. Subsequently, a small group of PAB-positive samples were subjected to SDS-PAGE, immunoblotting and 2-D PAGE. RESULTS We found that 20 % (6/30) ON patients, 47 % (22/47) MS patients and 9 % (7/81) controls tested PAB positive using ELISA analysis. High PAB levels were found in 2 (4 %) MS patients, 1 (3 %) ON patient and 2 (3 %) controls. PAB positivity in ELISA was confirmed by immunoblotting. Separation of proteasome subunits by 2D PAGE followed by immunoblotting revealed no particular PAB subunit preference. CONCLUSIONS A retrospective search in available patient files revealed that 6 of 6 (100.0 %) PAB-positive ON patients developed MS over time. Eight of 24 (33 %) PAB-negative ON patients developed MS over time and 47 % (14/30) of all ON patients developed MS. A series of patient CSF was analysed by ELISA to assess the possible correlation between PAB status of concurrent serum and CSF samples, but no correlation was found. However, the results from the six PAB-positive ON patients could potentially be of prognostic value.
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Affiliation(s)
- N H Beyer
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark
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Abstract
Activation of the ubiquitin-proteasome system has been described in different models of cardiac hypertrophy. Cardiac cell growth in response to pressure or volume overload, as well as physiological adaptive hypertrophy, is accompanied by an increase in protein ubiquitination, proteasome subunit expression, and proteasome activity. Importantly, an inhibition of proteasome activity prevents and reverses cardiac hypertrophy and remodelling in vivo. The focus of this review is to provide an update about the mechanisms by which proteasome inhibitors affect cardiac cell growth in adaptive and maladaptive models of cardiac hypertrophy. In the first part, we summarize how the proteasome affects both proteolysis and protein synthesis in a context of cardiac cell growth. In the second part, we show how proteasome inhibition can prevent and reverse cardiac hypertrophy and remodelling in response to different conditions of overload.
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Affiliation(s)
- Nadia Hedhli
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 185 South Orange Avenue, MSB G-609, Newark, NJ 07103, USA
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22
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Multiple Proteasome-Interacting Proteins Assist the Assembly of the Yeast 19S Regulatory Particle. Cell 2009; 137:900-13. [PMID: 19446323 DOI: 10.1016/j.cell.2009.05.005] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 04/27/2009] [Accepted: 05/01/2009] [Indexed: 11/21/2022]
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Brush JM, Kim K, Sayre JW, McBride WH, Iwamoto KS. Imaging of radiation effects on cellular 26S proteasome function in situ. Int J Radiat Biol 2009; 85:483-94. [PMID: 19401903 DOI: 10.1080/09553000902883794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE The classical radiobiological paradigm is that DNA is the target for cell damage caused by ionising radiation. However, evidence is accumulating that other constituents, such as the membrane, organelles, and proteins, are also important targets. We have shown that the isolated 26S proteasome is one such target and here we wish to substantiate it within the cell, in situ. MATERIALS AND METHODS We used confocal microscopy to quantitatively detect and subcellularly localise radiation-induced 26S proteasome inhibition in cells expressing an ornithine decarboxylase degron that targets a fused Zoanthus species green (ZsGreen) fluorescent protein reporter specifically to the 26S proteasome. RESULTS Exposure of cells to a range of radiation doses, even as low as 0.05 Gy inhibited 26S activity within minutes. Initially, punctate nuclear ZsGreen fluorescence was observed that became cytoplasmic after seven hours -- a pattern distinct from the diffuse homogeneous fluorescence of cells incubated in the conventional proteasome inhibitor MG-132. CONCLUSIONS Our study clearly indicates that the 26S proteasome is a radiation target with physiological consequences and introduces a new perspective in mechanistic investigations of cellular responses to stresses.
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Affiliation(s)
- James M Brush
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1714, USA
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24
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Gilfoy F, Fayzulin R, Mason PW. West Nile virus genome amplification requires the functional activities of the proteasome. Virology 2008; 385:74-84. [PMID: 19101004 PMCID: PMC7103393 DOI: 10.1016/j.virol.2008.11.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 07/28/2008] [Accepted: 11/20/2008] [Indexed: 12/15/2022]
Abstract
The lifecycle of intracellular pathogens, especially viruses, is intimately tied to the macromolecular synthetic processes of their host cell. In the case of positive-stranded RNA viruses, the ability to translate and, thus, replicate their infecting genome is dependent upon hijacking host proteins. To identify proteins that participate in West Nile virus (WNV) replication, we tested the ability of siRNAs designed to knock-down the expression of a large subset of human genes to interfere with replication of WNV replicons. Here we report that multiple siRNAs for proteasome subunits interfered with WNV genome amplification. Specificity of the interference was shown by demonstrating that silencing proteasome subunits did not interfere with Venezuelan equine encephalitis virus replicons. Drugs that blocked proteasome activity were potent inhibitors of WNV genome amplification even if cells were treated 12 h after infection, indicating that the proteasome is required at a post-entry stage(s) of the WNV infection cycle.
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Affiliation(s)
- Felicia Gilfoy
- Department of Pathology, University of Texas Medical Branch, Galveston, 77555-0436, USA
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25
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Crystal structure of a chaperone complex that contributes to the assembly of yeast 20S proteasomes. Nat Struct Mol Biol 2008; 15:228-36. [DOI: 10.1038/nsmb.1386] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 01/09/2008] [Indexed: 11/09/2022]
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26
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Drews O, Wildgruber R, Zong C, Sukop U, Nissum M, Weber G, Gomes AV, Ping P. Mammalian proteasome subpopulations with distinct molecular compositions and proteolytic activities. Mol Cell Proteomics 2007; 6:2021-31. [PMID: 17660509 DOI: 10.1074/mcp.m700187-mcp200] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proteasome-dependent protein degradation participates in multiple essential cellular processes. Modulation of proteasomal activities may alter cardiac function and disease phenotypes. However, cardiovascular studies reported thus far have yielded conflicting results. We hypothesized that a contributing factor to the contradicting literature may be caused by existing proteasome heterogeneity in the myocardium. In this investigation, we provide the very first direct demonstration of distinct proteasome subpopulations in murine hearts. The cardiac proteasome subpopulations differ in their molecular compositions and proteolytic activities. Furthermore they were distinguished from proteasome subpopulations identified in murine livers. The study was facilitated by the development of novel protocols for in-solution isoelectric focusing of multiprotein complexes in a laminar flow that support an average resolution of 0.04 pH units. Utilizing these protocols, the majority of cardiac proteasome complexes displayed an isoelectric point of 5.26 with additional subpopulations focusing in the range from pH 5.10 to 5.33. In contrast, the majority of hepatic 20 S proteasomes had a pI of 5.05 and focused from pH 5.01 to 5.29. Importantly proteasome subpopulations degraded specific model peptides with different turnover rates. Among cardiac subpopulations, proteasomes with an approximate pI of 5.21 showed 40% higher trypsin-like activity than those with pI 5.28. Distinct proteasome assembly may be a contributing factor to variations in proteolytic activities because proteasomes with pI 5.21 contained 58% less of the inducible subunit beta 2i compared with those with pI 5.28. In addition, dephosphorylation of 20 S proteasomes demonstrated that besides molecular composition posttranslational modifications largely contribute to their pI values. These data suggest the possibility of mixed 20 S proteasome assembly, a departure from the currently hypothesized two subpopulations: constitutive and immuno forms. The identification of multiple distinct proteasome subpopulations in heart provides key mechanistic insights for achieving selective and targeted regulation of this essential protein degradation machinery. Thus, proteasome subpopulations may serve as novel therapeutic targets in the myocardium.
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Affiliation(s)
- Oliver Drews
- Department of Physiology, Division of Cardiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
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27
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Castro-Borges W, Cartwright J, Ashton PD, Braschi S, Guerra Sa R, Rodrigues V, Wilson RA, Curwen RS. The 20S proteasome ofSchistosoma mansoni: A proteomic analysis. Proteomics 2007; 7:1065-75. [PMID: 17390295 DOI: 10.1002/pmic.200600166] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Proteasomes are molecular machines found in virtually all cells that provide one of the mechanisms for protein turnover. We have analysed the 20S proteasome of Schistosoma mansoni, the first multimeric complex isolated from this helminth parasite. Three chromatographic steps were employed to yield a highly homogeneous preparation. 2-DE of the purified complex revealed 58 spots, of which 46 could be assigned either an alpha or a beta proteasome signature by MS. Most of the 14 transcripts (7alpha and 7beta) encoded by the parasite genome were represented by multiple spots and we suggest that this diversity is due to PTMs of subunits. For most of the isoforms, variations in pI predominated although alterations in mass were also observed. 2-DE separations of extracts from infective cercariae and blood-dwelling adult worms probed by Western blotting, using a human anti-alpha subunit antibody, revealed different patterns of reactivity, most probably in alpha3 and alpha6 subunits, on the basis of sequence conservation. This difference was rapidly lost following transformation of the cercaria to the skin schistosomulum stage, suggesting that changes in the proteasome structure, likely caused by the introduction of a new set of PTMs, precede remodelling of the parasite body prior to intravascular migration.
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28
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Steverding D. The proteasome as a potential target for chemotherapy of African trypanosomiasis. Drug Dev Res 2007. [DOI: 10.1002/ddr.20188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Zavrski I, Jakob C, Kaiser M, Fleissner C, Heider U, Sezer O. Molecular and clinical aspects of proteasome inhibition in the treatment of cancer. Recent Results Cancer Res 2007; 176:165-76. [PMID: 17607924 DOI: 10.1007/978-3-540-46091-6_14] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The proteasome is a multicatalytic threonine protease responsible for intracellular protein turnover in eukaryotic cells, including the processing and degradation of several proteins involved in cell cycle control and the regulation of apoptosis. Preclinical studies have shown that the treatment with proteasome inhibitors results in decreased proliferation, induction of apoptosis, and sensitization of tumor cells against conventional chemotherapeutic agents and irradiation. The effects were conferred to stabilization of p21, p27, Bax, p53, I-KB, and the resulting inhibition of the nuclear factor-KB (NF-KB) activation. Bortezomib is the first proteasome inhibitor that has entered clinical trials. In multiple myeloma, both the FDA (United States Food and Drug Administration) and EMEA (European Medicine Evaluation Agency) granted an approval for the use of bortezomib (Velcade, Millennium Pharmaceuticals, Cambridge, MA, USA) for the treatment of relapsed multiple myeloma. At present, clinical trials are examining the activity in a variety of solid tumors and hematological malignancies.
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Affiliation(s)
- Ivana Zavrski
- Department of Hematology and Oncology, Charité Universitätsmedizin Berlin, Germany
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30
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Williamson MJ, Blank JL, Bruzzese FJ, Cao Y, Daniels JS, Dick LR, Labutti J, Mazzola AM, Patil AD, Reimer CL, Solomon MS, Stirling M, Tian Y, Tsu CA, Weatherhead GS, Zhang JX, Rolfe M. Comparison of biochemical and biological effects of ML858 (salinosporamide A) and bortezomib. Mol Cancer Ther 2006; 5:3052-61. [PMID: 17172407 DOI: 10.1158/1535-7163.mct-06-0185] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Strains within the genus Salinospora have been shown to produce complex natural products having antibiotic and antiproliferative activities. The biochemical basis for the cytotoxic effects of salinosporamide A has been linked to its ability to inhibit the proteasome. Synthetically accessible salinosporamide A (ML858) was used to determine its biochemical and biological activities and to compare its effects with those of bortezomib. ML858 and bortezomib show time- and concentration-dependent inhibition of the proteasome in vitro. However, unlike bortezomib, which is a reversible inhibitor, ML858 covalently binds to the proteasome, resulting in the irreversible inhibition of 20S proteasome activity. ML858 was equipotent to bortezomib in cell-based reporter stabilization assays, but due to intramolecular instability is less potent in long-term assays. ML858 failed to maintain levels of proteasome inhibition necessary to achieve efficacy in tumor models responsive to bortezomib. Our results show that ML858 and bortezomib exhibit different kinetic and pharmacologic profiles and suggest that additional characterization of ML858 is warranted before its therapeutic potential can be fully appreciated.
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Affiliation(s)
- Mark J Williamson
- Millennium Pharmaceuticals, Inc., 40 Landsdowne Street, Cambridge, MA 02139, USA.
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31
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Callahan MK, Wohlfert EA, Ménoret A, Srivastava PK. Heat Shock Up-Regulates lmp2 and lmp7 and Enhances Presentation of Immunoproteasome-Dependent Epitopes. THE JOURNAL OF IMMUNOLOGY 2006; 177:8393-9. [PMID: 17142736 DOI: 10.4049/jimmunol.177.12.8393] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The heat shock response is a canonical regulatory pathway by which cellular stressors such as heat and oxidative stress alter the expression of stress-responsive genes. Some of these stress-responsive genes (heat shock proteins and MHC class I (MHC I)-related chains) play a significant role in the immune system. In this study, we have investigated the impact of stimulating the heat shock response on genes involved in the MHC I presentation pathway. We report that two inducible subunits of the proteasome, lmp2 and lmp7, are transcriptionally up-regulated by heat shock in cells of mouse and human origin. Furthermore, heat-shocked cells show enhanced presentation of the immunoproteasome-dependent MHC I antigenic epitopes NP(118-126) of lymphocytic choriomeningitis virus and E1B(192-200) of adenovirus, but not immunoproteasome-independent epitopes such as tumor Ag AH1 and SV40 large T Ag epitope II(223-231). These findings show a novel immunological sequel to the cellular response to stress that may play a key role during fever or other homeostatic perturbations.
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Affiliation(s)
- Margaret K Callahan
- Center for Immunotherapy of Cancer and Infectious Diseases, University of Connecticut School of Medicine, Farmington, CT 06030, USA.
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32
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Shaw E. Cysteinyl proteinases and their selective inactivation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 63:271-347. [PMID: 2407065 DOI: 10.1002/9780470123096.ch5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The affinity-labeling of cysteinyl proteinases may now be carried out with a number of peptide-derived reagents with selectivity, particularly for reactions carried out in vitro. These reagents have been described with emphasis on their selectivity for cysteine proteinases and lack of action on serine proteinases, the most likely source of side reactions among proteinases. Perhaps a crucial feature of this selectivity is an enzyme-promoted activation due to initial formation of a hemiketal, which may destabilize the reagent. Prominent among the reagent types that have this class selectivity are the peptidyl diazomethyl ketones, the acyloxymethyl ketones, the peptidylmethyl sulfonium salts, and peptidyl oxides analogous to E-64. The need for specific inhibitors capable of inactivating the target enzyme in intact cells and animals is inevitably pushing the biochemical application of these inhibitors into more complex molecular environments where the possibilities of competing reactions are greatly increased. In dealing with the current state and potential developments for the in vivo use of affinity-labeling reagents of cysteine proteinases, the presently known variety of cysteinyl proteinases had to be considered. Therefore this chapter has, at the same time, attempted to survey these proteinases with respect to specificity and gene family. The continual discovery of new proteinases will increase the complexity of this picture. At present the lysosomal cysteine proteinases cathepsins B and L and the cytoplasmic calcium-dependent proteinases are reasonable goals for a fairly complete metabolic clarification. The ability of investigators to inactivate individual members of this family in vivo, possibly without complications due to concurrent inactivation of serine proteinases by improvements in reagent specificity, is increasing. Among the cysteine proteinases, at least those of the papain super family, hydrophobic interactions in the S2 and S3 subsites are important and some specificity has been achieved by taking advantage of topographical differences among members of this group. Some of this has probably involved surface differences removed from the regions involved in proteolytic action. The emerging cysteine proteinases include some which, in contrast to the papain family, have a pronounced specificity in S1 for the binding of basic side chains, familiar in the trypsin family of serine proteinases. At least a potential conflict with serine proteinases can be avoided by choice of a covalent bonding mechanism. The departing group region, has not been exploited. As a sole contributor to binding, this region may be rather limited as a source of specificity.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- E Shaw
- Friedrich Miescher-Institut, Basel, Switzerland
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Shibatani T, Carlson EJ, Larabee F, McCormack AL, Früh K, Skach WR. Global organization and function of mammalian cytosolic proteasome pools: Implications for PA28 and 19S regulatory complexes. Mol Biol Cell 2006; 17:4962-71. [PMID: 16987959 PMCID: PMC1679665 DOI: 10.1091/mbc.e06-04-0311] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Proteolytic activity of the 20S proteasome is regulated by activators that govern substrate movement into and out of the catalytic chamber. However, the physiological relationship between activators, and hence the relative role of different proteasome species, remains poorly understood. To address this problem, we characterized the total pool of cytosolic proteasomes in intact and functional form using a single-step method that bypasses the need for antibodies, proteasome modification, or column purification. Two-dimensional Blue Native(BN)/SDS-PAGE and tandem mass spectrometry simultaneously identified six native proteasome populations in untreated cytosol: 20S, singly and doubly PA28-capped, singly 19S-capped, hybrid, and doubly 19S-capped proteasomes. All proteasome species were highly dynamic as evidenced by recruitment and exchange of regulatory caps. In particular, proteasome inhibition with MG132 markedly stimulated PA28 binding to exposed 20S alpha-subunits and generated doubly PA28-capped and hybrid proteasomes. PA28 recruitment virtually eliminated free 20S particles and was blocked by ATP depletion. Moreover, inhibited proteasomes remained stably associated with distinct cohorts of partially degraded fragments derived from cytosolic and ER substrates. These data establish a versatile platform for analyzing substrate-specific proteasome function and indicate that PA28 and 19S activators cooperatively regulate global protein turnover while functioning at different stages of the degradation cycle.
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Affiliation(s)
- Toru Shibatani
- *Department of Biochemistry and Molecular Biology, Oregon Health & Sciences University, Portland, OR 97201; and
| | - Eric J. Carlson
- *Department of Biochemistry and Molecular Biology, Oregon Health & Sciences University, Portland, OR 97201; and
| | - Fredrick Larabee
- *Department of Biochemistry and Molecular Biology, Oregon Health & Sciences University, Portland, OR 97201; and
| | - Ashley L. McCormack
- Vaccine and Gene Therapy Institute, Oregon Health & Sciences University, Beaverton, OR 97006-3448
| | - Klaus Früh
- Vaccine and Gene Therapy Institute, Oregon Health & Sciences University, Beaverton, OR 97006-3448
| | - William R. Skach
- *Department of Biochemistry and Molecular Biology, Oregon Health & Sciences University, Portland, OR 97201; and
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Gomes AV, Zong C, Edmondson RD, Li X, Stefani E, Zhang J, Jones RC, Thyparambil S, Wang GW, Qiao X, Bardag-Gorce F, Ping P. Mapping the Murine Cardiac 26S Proteasome Complexes. Circ Res 2006; 99:362-71. [PMID: 16857966 DOI: 10.1161/01.res.0000237386.98506.f7] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The importance of proteasomes in governing the intracellular protein degradation process has been increasingly recognized. Recent investigations indicate that proteasome complexes may exist in a species- and cell-type-specific fashion. To date, despite evidence linking impaired protein degradation to cardiac disease phenotypes, virtually nothing is known regarding the molecular composition, function, or regulation of cardiac proteasomes. We have taken a functional proteomic approach to characterize 26S proteasomes in the murine heart. Multidimensional chromatography was used to obtain highly purified and functionally viable cardiac 20S and 19S proteasome complexes, which were subjected to electrophoresis and tandem mass spectrometry analyses. Our data revealed complex molecular organization of cardiac 26S proteasomes, some of which are similar to what were reported in yeast, whereas others exhibit contrasting features that have not been previously identified in other species or cell types. At least 36 distinct subunits (17 of 20S and 19 of 19S) are coexpressed and assembled as 26S proteasomes in this vital cardiac organelle, whereas the expression of PA200 and 11S subunits were detected with limited participation in the 26S complexes. The 19S subunits included a new alternatively spliced isoform of Rpn10 (Rpn10b) along with its primary isoform (Rpn10a). Immunoblotting and immunocytochemistry verified the expression of key alpha and beta subunits in cardiomyocytes. The expression of 14 constitutive alpha and beta subunits in parallel with their three inducible subunits (beta1i, beta2i, and beta5i) in the normal heart was not expected; these findings represent a distinct level of structural complexity of cardiac proteasomes, significantly different from that of yeast and human erythrocytes. Furthermore, liquid chromatography/tandem mass spectroscopy characterized 3 distinct types of post-translational modifications including (1) N-terminal acetylation of 19S subunits (Rpn1, Rpn5, Rpn6, Rpt3, and Rpt6) and 20S subunits (alpha2, alpha5, alpha7, beta3, and beta4); (2) N-terminal myristoylation of a 19S subunit (Rpt2); and (3) phosphorylation of 20S subunits (eg, alpha7)). Taken together, this report presents the first comprehensive characterization of cardiac 26S proteasomes, providing critical structural and proteomic information fundamental to our future understanding of this essential protein degradation system in the normal and diseased myocardium.
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Affiliation(s)
- Aldrin V Gomes
- Department of Physiology, Cardiac Proteomics and Signaling Laboratory at Cardiovascular Research Laboratories, University of California-Los Angeles 90095, USA
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Jørgensen JP, Lauridsen AM, Kristensen P, Dissing K, Johnsen AH, Hendil KB, Hartmann-Petersen R. Adrm1, a putative cell adhesion regulating protein, is a novel proteasome-associated factor. J Mol Biol 2006; 360:1043-52. [PMID: 16815440 DOI: 10.1016/j.jmb.2006.06.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 06/05/2006] [Accepted: 06/06/2006] [Indexed: 11/24/2022]
Abstract
We have identified Adrm1 as a novel component of the regulatory ATPase complex of the 26 S proteasome: Adrm1 was precipitated with an antibody to proteasomes and vice versa. Adrm1 co-migrated with proteasomes on gel-filtration chromatography and non-denaturing polyacrylamide gel electrophoresis. Adrm1 has been described as an interferon-gamma-inducible, heavily glycosylated membrane protein of 110 kDa. However, we found Adrm1 in mouse tissues only as a 42 kDa peptide, corresponding to the mass of the non-glycosylated peptide chain, and it could not be induced in HeLa cells with interferon. Adrm1 was present almost exclusively in soluble 26 S proteasomes, albeit a small fraction was membrane-associated, like proteasomes. Adrm1 was found in cells in amounts equimolar with S6a, a 26 S proteasome subunit. HeLa cells contain no pool of free Adrm1 but recombinant Adrm1 could bind to pre-existing 26 S proteasomes in cell extracts. Adrm1 may be distantly related to the yeast proteasome subunit Rpn13, mutants of which are reported to display no obvious phenotype. Accordingly, knock-down of Adrm1 in HeLa cells had no effect on the amount of proteasomes, or on degradation of bulk cell protein, or accumulation of polyubiquitinylated proteins. This indicates that Adrm1 has a specialised role in proteasome function.
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Affiliation(s)
- Jakob Ploug Jørgensen
- Institute of Molecular Biology and Physiology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
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Isono E, Saito N, Kamata N, Saeki Y, Toh-E A. Functional Analysis of Rpn6p, a Lid Component of the 26 S Proteasome, Using Temperature-sensitive rpn6 Mutants of the Yeast Saccharomyces cerevisiae. J Biol Chem 2005; 280:6537-47. [PMID: 15611133 DOI: 10.1074/jbc.m409364200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rpn6p is a component of the lid of the 26 S proteasome. We isolated and analyzed two temperature-sensitive rpn6 mutants in the yeast, Saccharomyces cerevisiae. Both mutants showed defects in protein degradation in vivo. However, the affinity-purified 26 S proteasome of the rpn6 mutants grown at the permissive temperature degraded polyubiquitinated Sic1p efficiently, even at a higher temperature. Interestingly, their enzyme activity was even higher at a higher temperature, indicating that once made mutant proteasomes are stable and have little defect in the proteolytic function. These results suggest that the deficiency in protein degradation observed in vivo is rather due to a defect in the assembly of a holoenzyme at the restrictive temperature. Indeed, both rpn6 mutants grown at the restrictive temperature were defective in assembling the 26 S proteasome. A striking feature of the rpn6 mutants at the restrictive temperature was that there appeared a protein complex composed of only four of the nine lid components, Rpn5p, Rpn8p, Rpn9p, and Rpn11p. Altogether, we conclude that Rpn6p is essential for the integrity/assembly of the lid in the sense that it is necessary for the incorporation of Rpn3p, Rpn7p, Rpn12p, and Sem1p (Rpn15p) into the lid, thereby playing an essential role in the proper function of the 26 S proteasome.
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Affiliation(s)
- Erika Isono
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
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37
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Barnett JA, Entian KD. A history of research on yeasts 9: regulation of sugar metabolism. Yeast 2005; 22:835-94. [PMID: 16134093 DOI: 10.1002/yea.1249] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- James A Barnett
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
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Isono E, Saeki Y, Yokosawa H, Toh-e A. Rpn7 Is Required for the Structural Integrity of the 26 S Proteasome of Saccharomyces cerevisiae. J Biol Chem 2004; 279:27168-76. [PMID: 15102831 DOI: 10.1074/jbc.m314231200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Rpn7 is one of the lid subunits of the 26 S proteasome regulatory particle. The RPN7 gene is known to be essential, but its function remains to be elucidated. To explore the function of Rpn7, we isolated and characterized temperature-sensitive rpn7 mutants. All of the rpn7 mutants obtained accumulated poly-ubiquitinated proteins when grown at the restrictive temperature. The N-end rule substrate (Ub-Arg-beta-galactosidase), the UFD pathway substrate (Ub-Pro-beta-galactosidase), and cell cycle regulators (Pds1 and Clb2) were found to be stabilized in experiments using one of the rpn7 mutants termed rpn7-3 at the restrictive temperature, indicating its defect in the ubiquitin-proteasome pathway. Subsequent analysis of the structure of the 26 S proteasome in rpn7-3 cells suggested that the defect was in the assembly of the 26 S holoenzyme. The most striking characteristic of the proteasome of the rpn7-3 mutant was that a lid subcomplex affinity-purified from the rpn7-3 cells grown at the restrictive temperature contained only 5 of the 8 lid components, a phenomenon that has not been reported in the previously isolated lid mutants. From these results, we concluded that Rpn7 is required for the integrity of the 26 S complex by establishing a correct lid structure.
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Affiliation(s)
- Erika Isono
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Tokyo 113-0033, Japan
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Brodsky IG, Suzara D, Furman M, Goldspink P, Ford GC, Nair KS, Kukowski J, Bedno S. Proteasome production in human muscle during nutritional inhibition of myofibrillar protein degradation. Metabolism 2004; 53:340-7. [PMID: 15015147 DOI: 10.1016/j.metabol.2003.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein undernutrition inhibits adenosine triphosphate (ATP)-dependent muscle protein degradation-a hallmark of the proteasome system. Here we report decreased myofibrillar protein degradation during dietary protein restriction without a concomitant decrease in proteasome gene expression, proteasome protein abundance, or proteasome in vivo fractional synthesis rate. Healthy human subjects consuming the average minimum adult protein requirement (0.71 g x kg(-1) fat-free mass x d(-1)) exhibited substantially lower (68%) excretion of 3-methylhistidine, an indicator of myofibrillar protein breakdown, when compared with subjects consuming an ample, American-style protein intake (1.67 g x kg(-1) fat-free mass x d(-1)). However, they displayed no difference in the expression of mRNA for proteasome subunits C2 or C3, in the content of C2 protein, or in the rate of incorporation of stable isotopically labeled l-[1-(13)C]-leucine into proteasome proteins. The results demonstrate that nutritional inhibition of myofibrillar protein degradation does not involve suppression in vivo of proteasome production in man. This suggests that other elements of the ubiquitin-proteasome system, such as ubiquitination pathways, are more important than proteasome abundance in the nutritional regulation of skeletal muscle mass.
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Affiliation(s)
- Irwin G Brodsky
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Abstract
Hematologic malignancies, including multiple myeloma (MM), will account for more than 100,000 new cases of cancer and over 57,000 deaths in the United States in 2003. Treatment of MM is a serious challenge, because despite a variety of available therapies, median survival is short. A new therapeutic area focuses on inhibiting the activity of the proteasome, a 26S protease complex involved in cell cycle regulation, cell adhesion, inflammation, and protein turnover. The novel proteasome inhibitor, bortezomib (Velcade), was recently approved for use in patients with refractory and relapsed MM and to date is the only proteasome inhibitor to have entered clinical trials. Bortezomib has demonstrated activity with manageable toxicity in a variety of hematologic malignancies in addition to MM, including leukemia and non-Hodgkin's lymphoma. This article reviews clinical information on bortezomib in hematologic malignancies both as monotherapy and in combination with dexamethasone. Preliminary reports of bortezomib in combination with Doxil (pegylated liposomal doxorubicin), melphalan, and thalidomide are discussed, and current trials are described. Available data suggest that bortezomib will be useful in the treatment of a variety of hematologic malignancies.
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Affiliation(s)
- Paul G Richardson
- Dana-Farber Cancer, Institute, Harvard Medical School, Boston, Massachusetts, USA.
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Sato N, Kawahara H, Toh-e A, Maeda T. Phosphorelay-regulated degradation of the yeast Ssk1p response regulator by the ubiquitin-proteasome system. Mol Cell Biol 2003; 23:6662-71. [PMID: 12944490 PMCID: PMC193698 DOI: 10.1128/mcb.23.18.6662-6671.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Saccharomyces cerevisiae, a phosphorelay signal transduction pathway composed of Sln1p, Ypd1p, and Ssk1p, which are homologous to bacterial two-component signal transducers, is involved in the osmosensing mechanism. In response to high osmolarity, the phosphorelay system is inactivated and Ssk1p remains unphosphorylated. Unphosphorylated Ssk1p binds to and activates the Ssk2p mitogen-activated protein (MAP) kinase kinase kinase, which in turn activates the downstream components of the high-osmolarity glycerol response (HOG) MAP kinase cascade. Here, we report a novel inactivation mechanism for Ssk1p involving degradation by the ubiquitin-proteasome system. Degradation is regulated by the phosphotransfer from Ypd1p to Ssk1p, insofar as unphosphorylated Ssk1p is degraded more rapidly than phosphorylated Ssk1p. Ubc7p/Qri8p, an endoplasmic reticulum-associated ubiquitin-conjugating enzyme, is involved in the phosphorelay-regulated degradation of Ssk1p. In ubc7Delta cells in which the degradation is hampered, the dephosphorylation and/or inactivation process of the Hog1p MAP kinase is delayed compared with wild-type cells after the hyperosmotic treatment. Our results indicate that unphosphorylated Ssk1p is selectively degraded by the Ubc7p-dependent ubiquitin-proteasome system and that this mechanism downregulates the HOG pathway after the completion of the osmotic adaptation.
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Affiliation(s)
- Naoto Sato
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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Brégégère F, Soroka Y, Bismuth J, Friguet B, Milner Y. Cellular senescence in human keratinocytes: unchanged proteolytic capacity and increased protein load. Exp Gerontol 2003; 38:619-29. [PMID: 12814797 DOI: 10.1016/s0531-5565(03)00059-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In order to assess the activity of cellular proteasome, we developed a method to permeabilize keratinocyte monolayers and measure proteasome activities intracellularly, using fluorogenic peptide substrates. The observed K(m) did not differ significantly in situ and in soluble extracts, and the K(i) of proteasome inhibitor MG132 was slightly higher in situ (34nM instead of 4nM). Inhibition studies in permeabilized cells showed that MG132 followed competitive inhibition patterns, and clasto-lactacystin beta-lactone non-competitive patterns, as expected. The observed velocities in situ (500pmoles/min/mg protein) were comparable to the best values of proteasome activity in crude cellular extracts. These features altogether allowed to identify the in situ activity as that of proteasome. To characterize proteasome complexes present in human keratinocytes, we analyzed cellular lysates by ultracentrifugation and gel filtration: most proteasome activity was associated with PA700-bound, presumably 26S, particles. PA28 activator was detected only when cells were treated by gamma interferon. Proteasome activities were determined using the in situ method in keratinocytes at different stages of replicative senescence. Only a slight decrease of proteasome activity per cell was seen at intermediate passages, followed by a slight increase in senescent cells. In the same time, the amount of total proteins increased notably with cellular ageing. Thus, proteasome activity decreased relatively to total proteins, but not relatively to cell numbers. Flow cytometry confirmed that the size of aged keratinocytes increased with the ageing marker beta-galactosidase.
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Affiliation(s)
- François Brégégère
- Laboratoire de Biologie et Biochimie Cellulaire du Vieillissement, Université Denis Diderot-Paris 7, C.C.7128, 2 place Jussieu, 752151 cédex 05, Paris, France. bregeger@paris7@.jussieu.fr
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Tanahashi-Hori T, Tanahashi N, Tanaka K, Chiba T. Conditional knockdown of proteasomes results in cell-cycle arrest and enhanced expression of molecular chaperones Hsp70 and Hsp40 in chicken DT40 cells. J Biol Chem 2003; 278:16237-43. [PMID: 12594202 DOI: 10.1074/jbc.m301331200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 26 S proteasome is an evolutionarily conserved ATP-dependent protease complex that degrades poly-ubiquitinated proteins and plays essential roles in a critical part of cellular regulation. In vertebrates, the roles of the proteasome have been widely studied by use of specific inhibitors, but not genetically. Here, we generated a cell line Z(-/-/-)/Z-HA, in which the expression of the catalytic subunit of the proteasome, Z (beta2) could be manipulated. This cell line expresses exogenous Z protein under the control of a tetracycline-repressible promoter in a Z-nullizygous genetic background. Treatment of these cells with doxycycline inhibited Z expression and, hence, the function of the proteasome. The latter resulted in accumulation of poly-ubiquitinated proteins and concomitant induction of molecular chaperones Hsp70 and Hsp40. These results suggest a synergistic role for the proteasome with these molecular chaperones to eliminate misfolded or damaged proteins in vivo. Furthermore, knockdown of the proteasome induced apoptotic cell death following cell-cycle arrest at G(2)/M phase. Our Z(-/-/-)/Z-HA cell line would be useful for evaluating proteolytic processes catalyzed by the proteasome in many biological events in vertebrate cells.
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Affiliation(s)
- Tomoko Tanahashi-Hori
- Department of Molecular Oncology, The Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan
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Tone Y, Toh-E A. Nob1p is required for biogenesis of the 26S proteasome and degraded upon its maturation in Saccharomyces cerevisiae. Genes Dev 2002; 16:3142-57. [PMID: 12502737 PMCID: PMC187499 DOI: 10.1101/gad.1025602] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nob1p is a nuclear protein that forms a complex with the 19S regulatory particle of the 26S proteasome and with uncharacterized nuclear protein Pno1p. Overexpression of NOB1 overrode the defects in maturation of the 20S proteasome of ump1Delta cells, and temperature-sensitive nob1 and pno1 mutants exhibited defects in the processing of the beta subunits and in the assembly of the 20S and the 26S proteasomes. A defect in either NOB1 or PNO1 caused accumulation of newly formed Pre6p in the cytoplasm, whereas Pre6p of the ump1Delta strain accumulated in the nucleus irrespective of the temperature. Here we present a model proposing that (1) Nob1p serves as a chaperone to join the 20S proteasome with the 19S regulatory particle in the nucleus and facilitates the maturation of the 20S proteasome and degradation of Ump1p, and (2) Nob1p is then internalized into the 26S proteasome and degraded to complete 26S proteasome biogenesis.
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Affiliation(s)
- Yoshiko Tone
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Japan
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45
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Thomas AR, Oosthuizen V, Naudé RJ, Muramoto K. Purification and characterization of the 20S proteasome from ostrich skeletal muscle. Biol Chem 2002; 383:1267-70. [PMID: 12437115 DOI: 10.1515/bc.2002.141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The proteasome is a high molecular weight, multisubunit and multicatalytic enzyme. Here we report the purification and characterization of ostrich skeletal muscle 20S proteasome. It was purified to homogeneity with Mr 700,000, pI 6.67 and a 'ladder' of 22.2-33.5 kDa bands on SDS-PAGE. The amino acid composition and amino-terminal sequences showed large identities to those of other species. For the three major activities, pH and temperature optima ranged between 8.0-11.0 and 40-70 degrees C, and stabilities between 5-12 and up to 40-60 degrees C. Substrate specificity and inhibitory effects were also studied. Many similarities to other sources were shown, with a few significant differences.
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Affiliation(s)
- Adele R Thomas
- Department of Biochemistry and Microbiology, University of Port Elizabeth, South Africa
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46
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47
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Yanagi S, Shimbara N, Tamura TA. Tissue and cell distribution of a mammalian proteasomal ATPase, MSS1, and its complex formation with the basal transcription factors. Biochem Biophys Res Commun 2000; 279:568-73. [PMID: 11118327 DOI: 10.1006/bbrc.2000.3969] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The proteasome is an eukaryotic multi-subunit protease complex composed of one 20S core component and two 19S regulatory complexes. The regulatory complex contains 6 putative ATPases. We investigated tissue and cell distribution of one of these ATPases, MSS1 (mammalian suppressor of sgv1). MSS1 was ubiquitously present in rat tissues as was the 20S core component of proteasome. However, the ratio of MSS1 to 20S varied greatly among tissues and MSS1 was concentrated in the thymus. Glycerol gradient sedimentation analysis revealed that MSS1 is included in protein complexes whose density is lighter than that of the proteasome. MSS1 was distributed in mammalian cells ubiquitously, while proteasome was rather concentrated in the nuclei. Hence, a novel molecular status of MSS1 distinct from proteasome is implicated. Interestingly, multiple basal transcription factors for RNA polymerase II, including TBP, TFIIB, TFIIH, and TFIIF, were found to be associated with MSS1. These results suggest that MSS1, in addition to proteolysis, plays a role in DNA metabolism including transcriptional regulation.
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Affiliation(s)
- S Yanagi
- Department of Biology, Faculty of Science, Chiba University, Japan
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48
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Usha R, Muralikrishnan D, Thomas B, Ghosh S, Mandal C, Mohanakumar KP. Region-specific attenuation of a trypsin-like protease in substantia nigra following dopaminergic neurotoxicity by 1-methyl-4-phenyl-1,2, 3,6-tetrahydropyridine. Brain Res 2000; 882:191-5. [PMID: 11056198 DOI: 10.1016/s0006-8993(00)02802-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We analysed apoptosis, caspase-1 and -3, and trypsin-like protease activity in the nigrostriatal pathway during 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP)-induced neurotoxicity. MPTP injected (30 mg/kg, i.p., twice, 16 h apart) mice were sacrificed on 1, 2 and 7 days. DNA extracted from nucleus caudatus putamen (NCP) and substantia nigra (SN) was subjected to agarose gel electrophoresis. Typical apoptotic-like DNA cleavage was absent in SN or NCP after this dose of MPTP. A trypsin-like protease activity was significantly decreased in SN and not in NCP. While caspase-3 activity in the whole brain was increased significantly, caspase-1 activity was unaffected. Striatal dopamine content was decreased to 75% by 7 days. The absence of typical DNA 'ladder' when there was severe striatal dopamine depletion suggests that in vivo MPTP-mediated dopaminergic neurotoxicity may not involve apoptotic cell death, and explains why in mice MPTP-induced dopamine depletion is transient. The region-specific decrease in trypsin-like protease activity and absence of caspase-3 activation in SN signify the importance of trypsin-like protease in the regulation of apoptosis in MPTP-neurotoxicity in mice.
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Affiliation(s)
- R Usha
- Protein Design and Engineering Division, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, 700 032, Calcutta, India
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Noda C, Tanahashi N, Shimbara N, Hendil KB, Tanaka K. Tissue distribution of constitutive proteasomes, immunoproteasomes, and PA28 in rats. Biochem Biophys Res Commun 2000; 277:348-54. [PMID: 11032729 DOI: 10.1006/bbrc.2000.3676] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the expression of standard proteasomes, immunoproteasomes, and their regulators, PA28, and PA700, in rat tissues. Immunoproteasomes (with subunits LMP2, LMP7, and MECL1) were abundant in the spleen but almost absent in the brain. In contrast, standard proteasomes (with X, Y, and Z) were highly expressed in the brain but not in the spleen. Both proteasome types were present in the lung and the liver. PA700 subunits (p112, S5a, and p45) were found in all tissues. PA28alpha, PA28beta, and PA28gamma were also expressed in all tissues, except for the brain which contained very little PA28beta. The results did not depend on rat sex or age. The cleavage specificity for peptide substrates differed greatly between brain and spleen proteasomes. Hybrid proteasomes, containing both PA28alphabeta and PA700, were not present in the brain but in all other tissues examined.
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Affiliation(s)
- C Noda
- Hyogo College, Kakogawa, Hyogo, 675-0101, Japan.
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Nishiyama A, Tachibana K, Igarashi Y, Yasuda H, Tanahashi N, Tanaka K, Ohsumi K, Kishimoto T. A nonproteolytic function of the proteasome is required for the dissociation of Cdc2 and cyclin B at the end of M phase. Genes Dev 2000; 14:2344-57. [PMID: 10995390 PMCID: PMC316931 DOI: 10.1101/gad.823200] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Inactivation of cyclin B-Cdc2 kinase at the exit from M phase depends on the specific proteolysis of the cyclin B subunit, whereas the Cdc2 subunit remains present at nearly constant levels throughout the cell cycle. It is unknown how Cdc2 escapes degradation when cyclin B is destroyed. In Xenopus egg extracts that reproduce the exit from M phase in vitro, we have found that dissociation of the cyclin B-Cdc2 complex occurred under conditions where cyclin B was tethered to the 26S proteasome but not yet degraded. The dephosphorylation of Thr 161 on Cdc2 was unlikely to be necessary for the dissociation of the two subunits. However, the dissociation was dependent on the presence of a functional destruction box in cyclin B. Cyclin B ubiquitination was also, by itself, not sufficient for separation of Cdc2 and cyclin B. The 26S proteasome, but not the 20S proteasome, was capable of dissociating the two subunits. These results indicate that the cyclin B and Cdc2 subunits are separated by the proteasome through a mechanism that precedes proteolysis of cyclin B and is independent of proteolysis. As a result, cyclin B levels decrease on exit from M phase but Cdc2 levels remain constant.
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Affiliation(s)
- A Nishiyama
- Laboratory of Cell and Developmental Biology, Graduate School of Biosciences, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8501, Japan
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