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Esfahanian N, Nelson M, Autenried R, Pattison JS, Callegari E, Rezvani K. Comprehensive Analysis of Proteasomal Complexes in Mouse Brain Regions Detects ENO2 as a Potential Partner of the Proteasome in the Striatum. Cell Mol Neurobiol 2022; 42:2305-2319. [PMID: 34037901 PMCID: PMC8617079 DOI: 10.1007/s10571-021-01106-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 05/19/2021] [Indexed: 11/28/2022]
Abstract
Defects in the activity of the proteasome or its regulators are linked to several pathologies, including neurodegenerative diseases. We hypothesize that proteasome heterogeneity and its selective partners vary across brain regions and have a significant impact on proteasomal catalytic activities. Using neuronal cell cultures and brain tissues obtained from mice, we compared proteasomal activities from two distinct brain regions affected in neurodegenerative diseases, the striatum and the hippocampus. The results indicated that proteasome activities and their responses to proteasome inhibitors are determined by their subcellular localizations and their brain regions. Using an iodixanol gradient fractionation method, proteasome complexes were isolated, followed by proteomic analysis for proteasomal interaction partners. Proteomic results revealed brain region-specific non-proteasomal partners, including gamma-enolase (ENO2). ENO2 showed more association to proteasome complexes purified from the striatum than to those from the hippocampus. These results highlight a potential key role for non-proteasomal partners of proteasomes regarding the diverse activities of the proteasome complex recorded in several brain regions.
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Affiliation(s)
- Niki Esfahanian
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Morgan Nelson
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Rebecca Autenried
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - J Scott Pattison
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Eduardo Callegari
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA
| | - Khosrow Rezvani
- Division of Basic Biomedical Sciences, Sanford School of Medicine,, University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD, 57069, USA.
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2
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Mathematical modeling and stochastic simulations suggest that low-affinity peptides can bisect MHC1-mediated export of high-affinity peptides into "early"- and "late"-phases. Heliyon 2021; 7:e07466. [PMID: 34286133 PMCID: PMC8278427 DOI: 10.1016/j.heliyon.2021.e07466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/23/2021] [Accepted: 06/29/2021] [Indexed: 02/01/2023] Open
Abstract
The peptide loading complex (PLC) is a multi-protein complex of the endoplasmic reticulum (ER) which optimizes major histocompatibility I (MHC1)-mediated export of intracellular high-affinity peptides. Whilst, the molecular biology of MHC1-mediated export is well supported by empirical data, the stoichiometry, kinetics and spatio-temporal profile of the participating molecular entities are a matter of considerable debate. Here, a low-affinity peptide-driven (LAPD)-model of MHC1-mediated high-affinity peptide export is formulated, implemented, analyzed and simulated. The model is parameterized in terms of the contribution of the shunt reaction to the concentration of exportable MHC1. Theoretical analyses and simulation studies of the model suggest that low-affinity peptides can bisect MHC1-mediated export of high-affinity peptides into time-dependent distinct “early”- and “late”-phases. The net exportable MHC1 (eM1β(t)) is a function of the retrograde (rM1β(t))- and anterograde (aM1β(t))-derived fractions. The “early”-phase is dominated by the contribution of the retrograde/recyclable (rM1β≈61%,aM1β≈39%) pathway to exportable MHC1, is characterized by Tapasin-mediated peptide-editing and is ATP-independent. The “late”-phase on the other hand, is characterized by de novo PLC-assembly, rapid disassembly and a significant contribution of the anterograde pathway to exportable MHC1 (rM1β≈21%,aM1β≈79%). The shunt reaction is rate limiting and may integrate peptide translocation with PLC-assembly/disassembly thereby, regulating peptide export under physiological and pathological (viral infections, dysplastic alterations) conditions.
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3
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Chronic pain susceptibility is associated with anhedonic behavior and alterations in the accumbal ubiquitin-proteasome system. Pain 2021; 162:1722-1731. [PMID: 33449505 DOI: 10.1097/j.pain.0000000000002192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 12/30/2020] [Indexed: 12/18/2022]
Abstract
ABSTRACT It remains unknown why on similar acute/subacute painful conditions, pain persists in some individuals while in others it resolves. Genetic factors, mood, and functional alterations, particularly involving the mesolimbic network, seem to be key. To explore potential susceptibility or resistance factors, we screened a large population of rats with a peripheral neuropathy and we isolated a small subset (<15%) that presented high thresholds (HTs) to mechanical allodynia (reduced pain manifestation). The phenotype was sustained over 12 weeks and was associated with higher hedonic behavior when compared with low-threshold (LT) subjects. The nucleus accumbens of HT and LT animals were isolated for proteomic analysis by Sequential Window Acquisition of All Theoretical Mass Spectra. Two hundred seventy-nine proteins displayed different expression between LT and HT animals or subjects. Among several protein families, the proteasome pathway repeatedly emerged in gene ontology enrichment and KEGG analyses. Several alpha and beta 20S proteasome subunits were increased in LT animals when compared with HT animals (eg, PSMα1, PSMα2, and PSMβ5). On the contrary, UBA6, an upstream ubiquitin-activating enzyme, was decreased in LT animals. Altogether these observations are consistent with an overactivation of the accumbal proteasome pathway in animals that manifest pain and depressive-like behaviors after a neuropathic injury. All the proteomic data are available through ProteomeXchange with identifier PXD022478.
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Bhaskar S, Gowda J, Prasanna J, Kumar A. Does altering proteasomal activity and trafficking reduce the arborization mediated specific vulnerability of SNpc dopaminergic neurons of Parkinson's disease? Med Hypotheses 2020; 143:110062. [PMID: 32652429 DOI: 10.1016/j.mehy.2020.110062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/27/2020] [Indexed: 01/15/2023]
Abstract
Parkinson's disease (PD) is a late-onset degenerative neuronal disorder and stands second among the neurological disorders with 1% of the total world population being affected. The disease originates majorly due to compromised function of the dopaminergic (DA) neurons in the Substantia Nigra pars compacta (SNpc), but not the ventral tegmental area (VTA) region of the midbrain. The differential susceptibility for degeneration is majorly attributed to morphological, molecular, and electrophysiological heterogeneity existing in DA neurons of SNpc and VTA. Long-range axonal arborization and a higher number of synapses in SNpc DA neurons make it more vulnerable compared to VTA DA neurons. Studies have shown that a decrease in such axonal arborization places DA neurons at decreased risk in PD. The two well established underlying mechanisms are a) As arborization is an energy-demanding process, increased redistribution of mitochondria to the axonal terminals occurs to satisfy the bioenergetic requirement b) The stabilization of axon-promoting factors at the axonal tip is an essential component for enhancing the arborization process. Interfering with any of these two processes would probably alleviate the degeneration of SNpc DA neurons. To accomplish the decreased stability of arborizing factors and thereby increase the resilience of SNpc DA neurons, we hypothesize the activation of anterograde transport-dependent recruitment of proteasomes to axon terminals as one of the most favorable approaches. Understanding this putative avenue of enhancing proteasomal activity and migration to the axonal tip could provide insight into the progression of neurodegeneration in PD and possibly offer a novel therapeutic strategy.
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Affiliation(s)
- Smitha Bhaskar
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Jeevan Gowda
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Jyothi Prasanna
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Anujith Kumar
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India.
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5
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Osmulski PA, Karpowicz P, Jankowska E, Bohmann J, Pickering AM, Gaczyńska M. New Peptide-Based Pharmacophore Activates 20S Proteasome. Molecules 2020; 25:E1439. [PMID: 32235805 PMCID: PMC7145288 DOI: 10.3390/molecules25061439] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 02/01/2023] Open
Abstract
The proteasome is a pivotal element of controlled proteolysis, responsible for the catabolic arm of proteostasis. By inducing apoptosis, small molecule inhibitors of proteasome peptidolytic activities are successfully utilized in treatment of blood cancers. However, the clinical potential of proteasome activation remains relatively unexplored. In this work, we introduce short TAT peptides derived from HIV-1 Tat protein and modified with synthetic turn-stabilizing residues as proteasome agonists. Molecular docking and biochemical studies point to the α1/α2 pocket of the core proteasome α ring as the binding site of TAT peptides. We postulate that the TATs' pharmacophore consists of an N-terminal basic pocket-docking "activation anchor" connected via a β turn inducer to a C-terminal "specificity clamp" that binds on the proteasome α surface. By allosteric effects-including destabilization of the proteasomal gate-the compounds substantially augment activity of the core proteasome in vitro. Significantly, this activation is preserved in the lysates of cultured cells treated with the compounds. We propose that the proteasome-stimulating TAT pharmacophore provides an attractive lead for future clinical use.
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Affiliation(s)
- Paweł A. Osmulski
- Department of Molecular Medicine, UT Health San Antonio, Texas, TX 78245, USA;
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, Texas, TX 78245, USA
| | - Przemysław Karpowicz
- Department of Organic Chemistry, Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland;
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland;
| | - Elżbieta Jankowska
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdansk, 80-308 Gdansk, Poland;
| | - Jonathan Bohmann
- Southwest Research Institute, San Antonio, Texas, TX 78238, USA;
| | - Andrew M. Pickering
- Department of Molecular Medicine, UT Health San Antonio, Texas, TX 78245, USA;
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, Texas, TX 78245, USA
- The Glenn Biggs Institute for Alzheimer’s & Neurodegenerative Diseases, UT Health San Antonio, TX 78229, USA
| | - Maria Gaczyńska
- Department of Molecular Medicine, UT Health San Antonio, Texas, TX 78245, USA;
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, Texas, TX 78245, USA
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6
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Lessons Learned from Proteasome Inhibitors, the Paradigm for Targeting Protein Homeostasis in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1243:147-162. [PMID: 32297217 DOI: 10.1007/978-3-030-40204-4_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Targeting aberrant protein homeostasis (proteostasis) in cancer is an attractive therapeutic strategy. However, this approach has thus far proven difficult to bring to clinical practice, with one major exception: proteasome inhibition. These small molecules have dramatically transformed outcomes for patients with the blood cancer multiple myeloma. However, these agents have failed to make an impact in more common solid tumors. Major questions remain about whether this therapeutic strategy can be extended to benefit even more patients. Here we discuss the role of the proteasome in normal and tumor cells, the basic, preclinical, and clinical development of proteasome inhibitors, and mechanisms proposed to govern both intrinsic and acquired resistance to these drugs. Years of study of both the mechanism of action and modes of resistance to proteasome inhibitors reveal these processes to be surprisingly complex. Here, we attempt to draw lessons from experience with proteasome inhibitors that may be relevant for other compounds targeting proteostasis in cancer, as well as extending the reach of proteasome inhibitors beyond blood cancers.
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Demasi M, da Cunha FM. The physiological role of the free 20S proteasome in protein degradation: A critical review. Biochim Biophys Acta Gen Subj 2018; 1862:2948-2954. [PMID: 30297324 DOI: 10.1016/j.bbagen.2018.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 08/27/2018] [Accepted: 09/12/2018] [Indexed: 01/26/2023]
Abstract
BACKGROUND It has been almost three decades since the removal of oxidized proteins by the free 20S catalytic unit of the proteasome (20SPT) was proposed. Since then, experimental evidence suggesting a physiological role of proteolysis mediated by the free 20SPT has being gathered. SCOPE OF REVIEW Experimental data that favors the hypothesis of free 20SPT as playing a role in proteolysis are critically reviewed. MAJOR CONCLUSIONS Protein degradation by the proteasome may proceed through multiple proteasome complexes with different requirements though the unequivocal role of the free 20SPT in cellular proteolysis towards native or oxidized proteins remains to be demonstrated. GENERAL SIGNIFICANCE The biological significance of proteolysis mediated by the free 20SPT has been elusive since its discovery. The present review critically analyzes the available experimental data supporting the proteolytic role of the free or single capped 20SPT.
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Affiliation(s)
- Marilene Demasi
- Laboratório de Bioquímica e Biofísica, Instituto Butantan, São Paulo, SP, Brazil.
| | - Fernanda Marques da Cunha
- Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
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8
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Nabavi SF, Atanasov AG, Khan H, Barreca D, Trombetta D, Testai L, Sureda A, Tejada S, Vacca RA, Pittalà V, Gulei D, Berindan-Neagoe I, Shirooie S, Nabavi SM. Targeting ubiquitin-proteasome pathway by natural, in particular polyphenols, anticancer agents: Lessons learned from clinical trials. Cancer Lett 2018; 434:101-113. [PMID: 30030139 DOI: 10.1016/j.canlet.2018.07.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 06/21/2018] [Accepted: 07/12/2018] [Indexed: 12/14/2022]
Abstract
The ubiquitin-proteasome pathway (UPP) is the main non-lysosomal proteolytic system responsible for degradation of most intracellular proteins, specifically damaged and regulatory proteins. The UPP is implicated in all aspects of the cellular metabolic networks including physiological or pathological conditions. Alterations in the components of the UPP can lead to stabilization of oncoproteins or augmented degradation of tumour suppressor favouring cancer appearance and progression. Polyphenols are natural compounds that can modulate proteasome activity or the expression of proteasome subunits. All together and due to the pleiotropic functions of UPP, there is a great interest in this proteasome system as a promising therapeutic target for the development of novel anti-cancer drugs. In the present review, the main features of the UPP and its implication in cancer development and progression are described, highlighting the importance of bioactive polyphenols that target the UPP as potential anti-cancer agents.
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Affiliation(s)
- Seyed Fazel Nabavi
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Atanas G Atanasov
- The Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Postępu 36A, Jastrzębiec, 05-552, Magdalenka, Poland; Department of Pharmacognosy, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Haroon Khan
- Department of Pharmacy, Abdul Wali Khan University, Mardan, Pakistan
| | - Davide Barreca
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98168, Messina, Italy.
| | - Domenico Trombetta
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98168, Messina, Italy
| | - Lara Testai
- Department of Pharmacy, University of Pisa, Pisa, Italy; Interdepartmental Center of Nutrafood, University of Pisa, Pisa, Italy
| | - Antoni Sureda
- Research Group on Community Nutrition and Oxidative Stress (NUCOX) and CIBEROBN (Physiopathology of Obesity and Nutrition CB12/03/30038), University of Balearic Islands, Palma de Mallorca, E-07122, Balearic Islands, Spain
| | - Silvia Tejada
- Laboratory of Neurophysiology, Department of Biology, University of Balearic Islands, Ctra. Valldemossa, Km 7,5, Ed, Guillem Colom, 07122, Balearic Islands, Spain
| | - Rosa Anna Vacca
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Italian National Council of Research, Bari, Italy
| | - Valeria Pittalà
- Department of Drug Sciences, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Diana Gulei
- MEDFUTURE-Research Center for Advanced Medicine, "Iuliu-Hatieganu" University of Medicine and Pharmacy, Marinescu 23 Street, 400337, Cluj-Napoca, Romania
| | - Ioana Berindan-Neagoe
- MEDFUTURE-Research Center for Advanced Medicine, "Iuliu-Hatieganu" University of Medicine and Pharmacy, Marinescu 23 Street, 400337, Cluj-Napoca, Romania; Research Center for Functional Genomics, Biomedicine and Translational Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, 23 Marinescu Street, 400337, Cluj-Napoca, Romania; Department of Functional Genomics and Experimental Pathology, The Oncology Institute "Prof. Dr. Ion Chiricuta", Republicii 34 Street, 400015, Cluj-Napoca, Romania
| | - Samira Shirooie
- Department of Pharmacology, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Seyed Mohammad Nabavi
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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9
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Marshall RS, Gemperline DC, Vierstra RD. Purification of 26S Proteasomes and Their Subcomplexes from Plants. Methods Mol Biol 2017; 1511:301-334. [PMID: 27730621 DOI: 10.1007/978-1-4939-6533-5_24] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The 26S proteasome is a highly dynamic, multisubunit, ATP-dependent protease that plays a central role in cellular housekeeping and many aspects of plant growth and development by degrading aberrant polypeptides and key cellular regulators that are first modified by ubiquitin. Although the 26S proteasome was originally enriched from plants over 30 years ago, only recently have significant advances been made in our ability to isolate and study the plant particle. Here, we describe two robust methods for purifying the 26S proteasome and its subcomplexes from Arabidopsis thaliana; one that involves conventional chromatography techniques to isolate the complex from wild-type plants, and another that employs the genetic replacement of individual subunits with epitope-tagged variants combined with affinity purification. In addition to these purification protocols, we describe methods commonly used to analyze the activity and composition of the complex.
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Affiliation(s)
- Richard S Marshall
- Department of Genetics, University of Wisconsin-Madison, 425-G Henry Mall, Madison, WI, USA.,Department of Biology, Washington University in St Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA
| | - David C Gemperline
- Department of Genetics, University of Wisconsin-Madison, 425-G Henry Mall, Madison, WI, USA
| | - Richard D Vierstra
- Department of Genetics, University of Wisconsin-Madison, 425-G Henry Mall, Madison, WI, USA. .,Department of Biology, Washington University in St Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA.
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10
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Asano S, Fukuda Y, Beck F, Aufderheide A, Förster F, Danev R, Baumeister W. Proteasomes. A molecular census of 26S proteasomes in intact neurons. Science 2015; 347:439-42. [PMID: 25613890 DOI: 10.1126/science.1261197] [Citation(s) in RCA: 252] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The 26S proteasome is a key player in eukaryotic protein quality control and in the regulation of numerous cellular processes. Here, we describe quantitative in situ structural studies of this highly dynamic molecular machine in intact hippocampal neurons. We used electron cryotomography with the Volta phase plate, which allowed high fidelity and nanometer precision localization of 26S proteasomes. We undertook a molecular census of single- and double-capped proteasomes and assessed the conformational states of individual complexes. Under the conditions of the experiment—that is, in the absence of proteotoxic stress—only 20% of the 26S proteasomes were engaged in substrate processing. The remainder was in the substrate-accepting ground state. These findings suggest that in the absence of stress, the capacity of the proteasome system is not fully used.
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Affiliation(s)
- Shoh Asano
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Yoshiyuki Fukuda
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Florian Beck
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Antje Aufderheide
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Friedrich Förster
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Radostin Danev
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany.
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11
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Chondrogianni N, Sakellari M, Lefaki M, Papaevgeniou N, Gonos ES. Proteasome activation delays aging in vitro and in vivo. Free Radic Biol Med 2014; 71:303-320. [PMID: 24681338 DOI: 10.1016/j.freeradbiomed.2014.03.031] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/18/2014] [Accepted: 03/18/2014] [Indexed: 02/02/2023]
Abstract
Aging is a natural biological process that is characterized by a progressive accumulation of macromolecular damage. In the proteome, aging is accompanied by decreased protein homeostasis and function of the major cellular proteolytic systems, leading to the accumulation of unfolded, misfolded, or aggregated proteins. In particular, the proteasome is responsible for the removal of normal as well as damaged or misfolded proteins. Extensive work during the past several years has clearly demonstrated that proteasome activation by either genetic means or use of compounds significantly retards aging. Importantly, this represents a common feature across evolution, thereby suggesting proteasome activation to be an evolutionarily conserved mechanism of aging and longevity regulation. This review article reports on the means of function of these proteasome activators and how they regulate aging in various species.
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Affiliation(s)
- Niki Chondrogianni
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry, and Biotechnology, 116 35 Athens, Greece.
| | - Marianthi Sakellari
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry, and Biotechnology, 116 35 Athens, Greece; Örebro University Medical School, Örebro, Sweden
| | - Maria Lefaki
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry, and Biotechnology, 116 35 Athens, Greece
| | - Nikoletta Papaevgeniou
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry, and Biotechnology, 116 35 Athens, Greece
| | - Efstathios S Gonos
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry, and Biotechnology, 116 35 Athens, Greece; Örebro University Medical School, Örebro, Sweden
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12
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13
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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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14
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Proteasome from rabbit skeletal muscle: Some properties and effects on muscle proteins. Meat Sci 2012; 45:451-62. [PMID: 22061668 DOI: 10.1016/s0309-1740(96)00126-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/1996] [Accepted: 10/20/1996] [Indexed: 11/20/2022]
Abstract
Rabbit proteasome, likely to be a 20S proteasome, was purified and its properties were investigated to clarify its contribution to proteolysis during meat conditioning. The purified enzyme migrated as a single band on non-denaturing polyacrylamide gel and dissociated to a number of subunits (20000-29000 Da) under denaturing conditions. The molecular mass of this enzyme was found to be 580 000-800 000 Da by Sephacryl S-300 column chromatography. The isoelectric point of this enzyme was 5.5. The optimum pH for hydrolysis of succinyl-Leu-Leu-Val-Tyr-(4-methylcoumaryl-7-amide) (Suc-LLVY-MCA) was 8. This enzyme was almost stable in the range of pH 5-9 and up to 60 °C at pH 7.2. The enzyme activity was inhibited by diisopropyl fluorophosphate (DFP) and chymostatin, but was not affected by EDTA, leupeptin, E-64, bestatin, monoiodoacetic acid or pepstatin. The enzyme was activated about 8-fold by 0.01% sodium dodecyl sulfate (SDS), but was not by ATP or CaCl(2). Remarkably, SDS increased the V(max) value of the enzyme. Rabbit proteasome was shown to degrade myosin heavy chain, α-actinin, actin, tropomyosin, troponins and myosin light chains in the presence of SDS. In the absence of SDS, no change in myofibrillar proteins was observed. This enzyme did not degrade any sarcoplasmic proteins regardless of the presence of SDS.
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15
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Abstract
Proteasome is a highly organized protease complex comprising a catalytic 20S core particle (CP) and two 19S regulatory particles (RP), which together form the 26S structure. The 26S proteasome is responsible for the degradation of most ubiquitylated proteins through a multistep process involving recognition of the polyubiquitin chain, unfolding of the substrate, and translocation of the substrate into the active site in the cavity of the CP. Recent studies have shed light on various aspects of the complex functions of the 26S proteasome. In addition, the recent identification of various proteasome-dedicated chaperones indicates that the assembly pathways of the RP and CP are multistep processes. In this review, we summarize recent advances in the understanding of the proteasome structure, function, and assembly.
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16
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Wang D, Zong C, Koag MC, Wang Y, Drews O, Fang C, Scruggs SB, Ping P. Proteome dynamics and proteome function of cardiac 19S proteasomes. Mol Cell Proteomics 2011; 10:M110.006122. [PMID: 21357515 DOI: 10.1074/mcp.m110.006122] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Myocardial proteasomes are comprised of 20S core particles and 19S regulatory particles, which together carry out targeted degradation of cardiac proteins. The 19S complex is unique among the regulators of proteasomes in that it affects both the capacity and specificity of protein degradation. However, a comprehensive molecular characterization of cardiac 19S complexes is lacking. In this investigation, we tailored a multidimensional chromatography-based purification strategy to isolate structurally intact and functionally viable 19S complexes from murine hearts. Two distinct subpopulations of 19S complexes were isolated based upon (1) potency of activating 20S proteolytic activity, and (2) molecular composition using a combination of immuno-detection, two-dimensional-differential gel electrophoresis, and MS-based approaches. Heat shock protein 90 (Hsp90) was identified to be characteristic to 19S subpopulation I. The physical interaction of Hsp90 with 19S complexes was demonstrated via multiple approaches. Inhibition of Hsp90 activity using geldanamycin or BIIB021 potentiated the ability of subpopulation I to activate 20S proteasomes in the murine heart, thus demonstrating functional specificity of Hsp90 in subpopulation I. This investigation has advanced our understanding of the molecular heterogeneity of cardiac proteasomes by identifying molecularly and functionally distinct cardiac 19S complexes. The preferential association of Hsp90 with 19S subpopulation I unveils novel targets for designing proteasome-based therapeutic interventions for combating cardiac disease.
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Affiliation(s)
- Ding Wang
- Department of Physiology and Medicine, Division of Cardiology, University of California at Los Angeles, UCLA School of Medicine, Los Angeles, California 90095, USA
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17
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Bhat KP, Greer SF. Proteolytic and non-proteolytic roles of ubiquitin and the ubiquitin proteasome system in transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1809:150-5. [PMID: 21184853 DOI: 10.1016/j.bbagrm.2010.11.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 11/29/2010] [Accepted: 11/30/2010] [Indexed: 01/15/2023]
Abstract
The ubiquitin proteasome system (UPS) regulates perhaps the most intriguing balance in all of biology: how cells control protein function and malfunction in order to regulate, and eventually eliminate, the old and error prone while simultaneously synthesizing and orchestrating the new. In light of the growing notion that ubiquitination and the 26S proteasome are central to a multiplicity of diverse cellular functions, we discuss here the proteolytic and non-proteolytic roles of the UPS in regulating pathways ultimately involved in protein synthesis and activity including roles in epigenetics, transcription, and post-translational modifications. This article is part of a Special Issue entitled The 26S Proteasome: When degradation is just not enough!
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Affiliation(s)
- Kavita P Bhat
- Division of Cellular and Molecular Biology and Phsyiclogy, Department of Biology, Georgia State University, Atlanta, GA 30302, USA
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18
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Xie Y. Structure, Assembly and Homeostatic Regulation of the 26S Proteasome. J Mol Cell Biol 2010; 2:308-17. [DOI: 10.1093/jmcb/mjq030] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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19
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Dasuri K, Nguyen A, Zhang L, Fernandez-Kim OS, Bruce-Keller AJ, Blalock BA, Cabo RD, Keller JN. Comparison of rat liver and brain proteasomes for oxidative stress-induced inactivation: Influence of ageing and dietary restriction. Free Radic Res 2009; 43:28-36. [PMID: 19048434 DOI: 10.1080/10715760802534812] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The present study examined brain and liver derived proteasome complexes to elucidate if there is a differential susceptibility in proteasome complexes from these tissues to undergo inactivation following exposure to oxidative stressors. It then examined the influence of ageing and dietary restriction (DR) on the observed proteasome inactivation. Studies used a filtration based methodology that allows for enrichment of proteasome complexes with less tissue than is required for traditional chromatography procedures. The results indicate that the brain has much lower levels of overall proteasome activity and exhibits increased sensitivity to hydrogen peroxide mediated inactivation as compared to proteasome complexes derived from the liver. Interestingly, the brain proteasome complexes did not appear to have increased susceptibility to 4-hydroxynonenal (HNE)-induced inactivation. Surprisingly, ageing and DR induced minimal effects on oxidative stress mediated proteasome inhibition. These results indicate that the brain not only has lower levels of proteasome activity compared to the liver, but is also more susceptible to inactivation following exposure to some (but certainly not all) oxidative stressors. This data also suggest that ageing and DR may not significantly modulate the resistance of the proteasome to inactivation in some experimental settings.
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Affiliation(s)
- Kalavathi Dasuri
- Pennington Biomedical Research Center/Louisiana State University System, Baton Rouge, LA 70808-4124, USA
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20
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Marques AJ, Palanimurugan R, Matias AC, Ramos PC, Dohmen RJ. Catalytic mechanism and assembly of the proteasome. Chem Rev 2009; 109:1509-36. [PMID: 19265443 DOI: 10.1021/cr8004857] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- António J Marques
- Institute for Genetics, University of Cologne, Zulpicher Strasse 47, D-50674 Cologne, Germany
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21
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Tanaka K. The proteasome: overview of structure and functions. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2009; 85:12-36. [PMID: 19145068 PMCID: PMC3524306 DOI: 10.2183/pjab.85.12] [Citation(s) in RCA: 533] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The proteasome is a highly sophisticated protease complex designed to carry out selective, efficient and processive hydrolysis of client proteins. It is known to collaborate with ubiquitin, which polymerizes to form a marker for regulated proteolysis in eukaryotic cells. The highly organized proteasome plays a prominent role in the control of a diverse array of basic cellular activities by rapidly and unidirectionally catalyzing biological reactions. Studies of the proteasome during the past quarter of a century have provided profound insights into its structure and functions, which has appreciably contributed to our understanding of cellular life. Many questions, however, remain to be elucidated.
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Affiliation(s)
- Keiji Tanaka
- Laboratory of Frontier Science, Tokyo Metropolitan Institute of Medical Science, Japan.
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22
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Rockel B, Baumeister W. A tale of two giant proteases. ERNST SCHERING FOUNDATION SYMPOSIUM PROCEEDINGS 2008:17-40. [PMID: 19198062 DOI: 10.1007/2789_2008_099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The 26S proteasome and tripeptidyl peptidase II (TPPII) are two exceptionally large eukaryotic protein complexes involved in intracellular proteolysis, where they exert their function sequentially: the proteasome, a multisubunit complex of 2.5 MDa, acts at the downstream end of the ubiquitin pathway and degrades ubiquitinylated proteins into small oligopeptides. Such oligopeptides are substrates for TPPII, a 6-MDa homooligomer, which releases tripeptides from their free N-terminus. Both 26S and TPPII are very fragile complexes refractory to crystallization and in their fully assembled native form have been visualized only by electron microscopy. Here, we will discuss the structural features of the two complexes and their functional implications.
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Affiliation(s)
- B Rockel
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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23
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Abstract
The ubiquitin proteasome system (UPS) represents a major pathway for intracellular protein degradation. Proteasome dependent protein quality control participates in cell cycle, immune response and apoptosis. Therefore, the UPS is in focus of therapeutic investigations and the development of pharmaceutical agents. Detailed analyses on proteasome structure and function are the foundation for drug development and clinical studies. Proteomic approaches contributed significantly to our current knowledge in proteasome research. In particular, 2-DE has been essential in facilitating the development of current models on molecular composition and assembly of proteasome complexes. Furthermore, developments in MS enabled identification of UPS proteins and their PTMs at high accuracy and high-throughput. First results on global characterization of the UPS are also available. Although the UPS has been intensively investigated within the last two decades, its functional significance and contribution to the regulation of cell and tissue phenotypes remain to be explored. This review recapitulates a variety of applied proteomic approaches in proteasome exploration, and presents an overview of current technologies and their potential in driving further investigations.
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Affiliation(s)
- Oliver Drews
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
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24
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Nickell S, Mihalache O, Beck F, Hegerl R, Korinek A, Baumeister W. Structural analysis of the 26S proteasome by cryoelectron tomography. Biochem Biophys Res Commun 2006; 353:115-20. [PMID: 17173858 DOI: 10.1016/j.bbrc.2006.11.141] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 11/27/2006] [Indexed: 11/15/2022]
Abstract
The 26S proteasome is the key enzyme of intracellular protein degradation in eukaryotic cells. It is a multisubunit complex of 2.5 MDa confining the proteolytic action to an inner compartment with tightly controlled access. Structural studies of this intriguing molecular machine have been hampered by its intrinsic instability and its dynamics. Here we have used an unconventional approach to obtain a three-dimensional structure of the holocomplex uncompromised by preparation-induced alterations and unbiased by any starting model. We have performed a tomographic reconstruction, followed by averaging over approx. 150 individual reconstructions, of Drosophila 26S proteasomes suspended in a thin layer of amorphous ice.
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Affiliation(s)
- Stephan Nickell
- Max-Planck-Institute of Biochemistry, Department of Structural Biology, Am Klopferspitz 18, D-82152 Martinsried, Germany
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25
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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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26
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Shirley RB, Kaddour-Djebbar I, Patel DM, Lakshmikanthan V, Lewis RW, Kumar MV. Combination of proteasomal inhibitors lactacystin and MG132 induced synergistic apoptosis in prostate cancer cells. Neoplasia 2006; 7:1104-11. [PMID: 16354593 PMCID: PMC1501172 DOI: 10.1593/neo.05520] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 09/30/2005] [Accepted: 10/03/2005] [Indexed: 12/16/2022] Open
Abstract
The proteasome inhibitor Velcade (bortezomib/PS-341) has been shown to block the targeted proteolytic degradation of short-lived proteins that are involved in cell maintenance, growth, division, and death, advocating the use of proteasomal inhibitors as therapeutic agents. Although many studies focused on the use of one proteasomal inhibitor for therapy, we hypothesized that the combination of proteasome inhibitors Lactacystin (AG Scientific, Inc., San Diego CA) and MG132 (Biomol International, Plymouth Meeting, PA) may be more effective in inducing apoptosis. Additionally, this regimen would enable the use of sublethal doses of individual drugs, thus reducing adverse effects. Results indicate a significant increase in apoptosis when LNCaP prostate cancer cells were treated with increasing levels of Lactacystin, MG132, or a combination of sublethal doses of these two inhibitors. Furthermore, induction in apoptosis coincided with a significant loss of IKKalpha, IKKbeta, and IKKgamma proteins and NFkappaB activity. In addition to describing effective therapeutic agents, we provide a model system to facilitate the investigation of the mechanism of action of these drugs and their effects on the IKK-NFkappaB axis.
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Affiliation(s)
- Robert B Shirley
- Department of Urology, Medical College of Georgia, Augusta, GA 30912, USA
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27
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Gomes AV, Zong C, Edmondson RD, Berhane BT, Wang GW, Le S, Young G, Zhang J, Vondriska TM, Whitelegge JP, Jones RC, Joshua IG, Thyparambil S, Pantaleon D, Qiao J, Loo J, Ping P. The murine cardiac 26S proteasome: an organelle awaiting exploration. Ann N Y Acad Sci 2005; 1047:197-207. [PMID: 16093497 DOI: 10.1196/annals.1341.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Multiprotein complexes have been increasingly recognized as essential functional units for a variety of cellular processes, including the protein degradation system. Selective degradation of proteins in eukaryotes is primarily conducted by the ubiquitin proteasome system. The current knowledge base, pertaining to the proteasome complexes in mammalian cells, relies largely upon information gained in the yeast system, where the 26S proteasome is hypothesized to contain a 20S multiprotein core complex and one or two 19S regulatory complexes. To date, the molecular structure of the proteasome system, the proteomic composition of the entire 26S multiprotein complexes, and the specific designated function of individual components within this essential protein degradation system in the heart remain virtually unknown. A functional proteomic approach, employing multidimensional chromatography purification combined with liquid chromatography tandem mass spectrometry and protein chemistry, was utilized to explore the murine cardiac 26S proteasome system. This article presents an overview on the subject of protein degradation in mammalian cells. In addition, this review shares the limited information that has been garnered thus far pertaining to the molecular composition, function, and regulation of this important organelle in the cardiac cells.
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Affiliation(s)
- Aldrin V Gomes
- Department of Physiology and Medicine, and Cardiac Proteomics and Signaling Lab at the Cardiovascular Research Laboratory, University of California at Los Angeles, School of Medicine, Los Angeles, California 90095, USA
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28
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Whittier JE, Xiong Y, Rechsteiner MC, Squier TC. Hsp90 enhances degradation of oxidized calmodulin by the 20 S proteasome. J Biol Chem 2004; 279:46135-42. [PMID: 15319444 DOI: 10.1074/jbc.m406048200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 20 S proteasome has been suggested to play a critical role in mediating the degradation of abnormal proteins under conditions of oxidative stress and has been found in tight association with the molecular chaperone Hsp90. To elucidate the role of Hsp90 in promoting the degradation of oxidized calmodulin (CaM(ox)), we have purified red blood cell 20 S proteasomes free of Hsp90 and assessed their ability to degrade CaM(ox) in the absence or presence of Hsp90. Purified 20 S proteasome does not degrade CaM(ox) unless Hsp90 is added. CaM(ox) degradation is sensitive to both proteasome and Hsp90-specific inhibitors and is further enhanced in the presence of 2 mm ATP. Irrespective of the presence of Hsp90, we find that unoxidized CaM is not significantly degraded. Direct binding measurements demonstrate that Hsp90 selectively associates with CaM(ox); essentially no binding is observed between Hsp90 and unoxidized CaM. These results indicate that Hsp90 in association with the 20 S proteasome can selectively associate with oxidized and partially unfolded CaM to promote degradation by the proteasome.
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Affiliation(s)
- Jennifer E Whittier
- Cell Biology and Biochemistry Group, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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29
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Kopp F, Kuehn L. Orientation of the 19S regulator relative to the 20S core proteasome: an immunoelectron microscopic study. J Mol Biol 2003; 329:9-14. [PMID: 12742014 DOI: 10.1016/s0022-2836(03)00402-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Specific labelling with monoclonal antibodies reveals that in regulator-proteasome complexes the asymmetric 19S regulator (PA700) binds to one or both terminal alpha-disks of the cylinder-shaped 20S core proteasome in such a way that its reclining front part is positioned in the vicinity of proteasome subunit alpha6. The protruding rear part of the regulator appears to be situated distal to the sites occupied by the subunits alpha2 and alpha3, respectively. When viewed from beta1/beta1' to beta4/beta4' along the polar 2-fold axis of the 20S proteasome core, the rear part of each 19S regulator cap appears to protrude clockwise. Thus, a defined alignment of the 19S regulator with respect to the single polar 2-fold rotational axis of the 20S core proteasome is obtained.
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Affiliation(s)
- Friedrich Kopp
- Klinische Biochemie und Pathobiochemie, Deutsches Diabetes-Forschungsinstitut, Leibniz-Institut an der Heinrich-Heine-Universität Düsseldorf, Auf'm Hennekamp 65, 40225, Düsseldorf, Germany.
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30
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Holtz KM, Rice AM, Sartorelli AC. Lithium chloride inactivates the 20S proteasome from WEHI-3B D+ leukemia cells. Biochem Biophys Res Commun 2003; 303:1058-64. [PMID: 12684043 DOI: 10.1016/s0006-291x(03)00473-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
LiCl interacts synergistically with all-trans-retinoic acid, promoting the terminal differentiation of WEHI-3B D(+) cells, a phenomenon partially due to the ability of the monovalent lithium cation to inhibit the proteasome-dependent degradation of retinoic acid receptor alpha protein. In this report, the 20S proteasome was purified from WEHI-3B D(+) cells and the effects of LiCl on chymotrypsin-like (Chtl) activity and peptidyl-glutamyl peptide hydrolyzing (PGPH) activity were determined. LiCl functions to inactivate both proteasomal activities in a time-dependent manner, without affecting non-proteasomal proteases. The half-lives for inactivation of Chtl and PGPH hydrolyzing activities were approximately 23 and 36min, respectively, at 10mM LiCl. Both SDS and peptide substrate increased the rate of inactivation. Partial enzymatic activity was recovered after dialysis in the absence of SDS, indicating that the off-rate for lithium was extremely slow. The findings suggest that the inactivation of Chtl and PGPH activities by LiCl occurs through a proteasomal conformational change.
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Affiliation(s)
- Kathleen M Holtz
- Department of Pharmacology and Developmental Therapeutics Program, Cancer Center, Yale University School of Medicine, New Haven, CT 06520, USA
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31
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Carrard G, Bulteau AL, Petropoulos I, Friguet B. Impairment of proteasome structure and function in aging. Int J Biochem Cell Biol 2002; 34:1461-74. [PMID: 12200039 DOI: 10.1016/s1357-2725(02)00085-7] [Citation(s) in RCA: 197] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Damage to macromolecules, and in particular protein, implicated in the cellular degeneration that occurs during the aging process, is corroborated by the accumulation of oxidative end-products over time. Oxidized protein build up is commonly seen as a hallmark of cellular aging. Protein turnover is essential to preserve cell function and the main proteolytic system in charge of cytosolic protein degradation is the proteasome. The proteasome is a multi-catalytic proteolytic complex, which recognizes and selectively degrades oxidatively damaged and ubiquitinated proteins. One of the hypothesis put forward to explain the accumulation of altered proteins is the decrease of proteasome activity with age. Indeed, accumulation of altered protein can be explained by increased protein alteration, decreased protein degradation or the combination of both. A short description of proteasome structure and of its role in cellular functions is first given. Then, accumulation of damaged protein is presented with emphasis on the pathways implicated in the formation of altered proteins. Finally, evidence for an age-related impairment of proteasome structure and function that has been reported by different groups is provided in the light of proteasomal dysfunction induced upon oxidative stress. It is now clear that proteasome activity is declining with age and that the loss in proteasome activity during aging is dependent of at least three different mechanisms: decreased proteasome expression; alterations and/or replacement of proteasome subunits and formation of inhibitory cross-linked proteins. However, it is also clear that events leading to the age- and disease-related loss of proteasome function have not yet been fully characterized.
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Affiliation(s)
- Géraldine Carrard
- Laboratoire de Biologie et Biochimie Cellulaire du Vieillissement, Université Paris 7, Denis Diderot, 2 place Jussieu, 75251 Cedex 05, Paris, France
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32
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Abstract
The accumulation of oxidized proteins in cells and tissues is a feature of a number of age-related diseases and may also occur as a result of the aging process itself. In this article we review recent advances in our understanding of the cellular degradation of oxidized proteins directing our attention primarily to information which directly bears on the behavior of intact eukaryotic cells. We summarize new work on the key intracellular degradative machineries, proteasomes and lysosomes and examine evidence implicating an increase in protein hydrophobicity as the primary signal to the proteasome to initiate degradation. The data identifying the proteasome as the main route of degradation of oxidized proteins is examined, as well as recent data investigating changes in proteasome function after exposure of cells to oxidants and the altered catabolism of oxidized proteins in aging cells. Evidence for the cooperation between the lysosomal and proteasomal systems in the degradation of oxidized proteins is discussed. We conclude that the cellular catabolism of oxidized proteins may be a more complex process than it first appeared and suggest key issues that need to be resolved to improve our understanding of this important process.
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Affiliation(s)
- Rachael A Dunlop
- Cell Biology Unit, The Heart Research Institute, 145 Missenden Road, Camperdown, Sydney, NSW, 2050 Australia
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33
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Lee C, Prakash S, Matouschek A. Concurrent translocation of multiple polypeptide chains through the proteasomal degradation channel. J Biol Chem 2002; 277:34760-5. [PMID: 12080075 DOI: 10.1074/jbc.m204750200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proteasome can actively unfold proteins by sequentially unraveling their substrates from the attachment point of the degradation signal. To investigate the steric constraints imposed on substrate proteins during their degradation by the proteasome, we constructed a model protein in which specific parts of the polypeptide chain were covalently connected through disulfide bridges. The cross-linked model proteins were fully degraded by the proteasome, but two or more cross-links retarded the degradation slightly. These results suggest that the pore of the proteasome allows the concurrent passage of at least three stretches of a polypeptide chain. A degradation channel that can tolerate some steric bulk may reconcile the two opposing needs for degradation that is compartmentalized to avoid aberrant proteolysis yet able to handle a range of substrates of various sizes.
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Affiliation(s)
- Cheolju Lee
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500, USA
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34
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Zwickl P, Seemüller E, Kapelari B, Baumeister W. The proteasome: a supramolecular assembly designed for controlled proteolysis. ADVANCES IN PROTEIN CHEMISTRY 2002; 59:187-222. [PMID: 11868272 DOI: 10.1016/s0065-3233(01)59006-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- P Zwickl
- Department of Molecular Structural Biology, Max-Planck Institute for Biochemistry, Am Klopferspitz 18a, 82152 Martinsried, Germany
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35
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Kopp F, Dahlmann B, Kuehn L. Reconstitution of hybrid proteasomes from purified PA700-20 S complexes and PA28alphabeta activator: ultrastructure and peptidase activities. J Mol Biol 2001; 313:465-71. [PMID: 11676531 DOI: 10.1006/jmbi.2001.5063] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The activity of the proteasome, the major non-lysosomal proteinase in eukaryotes, is stimulated by two activator complexes, PA700 and PA28. PA700-20 S-PA700 proteasome complexes, generally designated as 26 S proteasomes, degrade proteins, whereas complexes of the type PA28-20 S-PA28 degrade only peptides. We report, for the first time, the in vitro reconstitution of previously identified hybrid proteasomes (PA700-20 S-PA28) from purified PA700-20 S proteasome complexes and PA28 activator. In electron micrographs, the hybrid appears as a corkscrew-shaped particle with a PA700 and a PA28 activator each bound to a terminal alpha-disk of the 20 S core proteasome. The multiple peptidase activities of hybrid proteasomes are not different from those of PA28-20 S-PA28 or PA700-20 S-PA700 complexes.
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Affiliation(s)
- F Kopp
- Department of Clinical Biochemistry, Deutsches Diabetes-Forschungsinstitut, Düsseldorf, Germany
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36
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Abstract
A two-hybrid screen against an activation domain array of Saccharomyces cerevisiae proteins was carried out for 31 yeast proteasome proteins. Fifty-five putative interactions were identified: 21 between components of the proteasome complex and 34 between proteasome proteins and other proteins. Many of these latter interactions involved either proteins of the ubiquitin pathway, cell cycle proteins, protein kinases or a translation initiation factor subunit. The role of eleven proteins associated with proteasome function by these screens was analyzed by examining the corresponding deletion strains for temperature sensitivity and canavanine sensitivity and for the stability of a ubiquitin-beta-galactosidase fusion protein. These assays additionally implicated three proteins, Bim1, Ump1, and YKL171W, in proteasome function. This study demonstrates the utility of genome-wide two-hybrid assays as an entry point for the further analysis of a large protein complex.
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Affiliation(s)
- G Cagney
- Departments of Genetics and Medicine, Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195-7360, USA
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37
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Bardag-Gorce F, French BA, Lue YH, Nguyen V, Wan YJ, French SW. Mallory bodies formed in proteasome-depleted hepatocytes: an immunohistochemical study. Exp Mol Pathol 2001; 70:7-18. [PMID: 11170786 DOI: 10.1006/exmp.2000.2343] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mallory bodies (MBs) are aggregates of proteins, principally cytokeratin proteins found in liver cells. They are also found in a few other cell types such as type II pneumocytes and trophoblasts. Studies on the liver thus far indicate that MBs are derived from hyperphosphorylated, heavily ubiquitinated proteins which have undergone conformational change. The aggregated protein may accumulate because of the failure of the proteasome to remove the altered proteins from the cytoplasm of liver cells. To investigate this possibility, the proteasomes were assessed immunohistochemically in individual liver cells of mice fed a drug which induced MB formation. To accelerate and enhance MB formation, cytochrome P450 2EI knockout mice were used. Proteasomes in individual cells were visualized by immunofluorescence using an antibody to a subunit of the proteasome (P25). The results showed that the groups of liver cells that had formed MBs were often partially depleted of proteasomes. These findings support the possibility that MBs formed as a result of the loss of the proteasome to remove misfolded cytokeratin proteins. Thus MBs may share their pathogenesis with other types of cellular inclusions seen where proteins aggregate in the cytoplasm due to mutation, misfolding, or loss of proteasomes.
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Affiliation(s)
- F Bardag-Gorce
- Department of Pathology and Medicine, Harbor-UCLA Medical Center, 1000 W. Carson Street, Torrance, California 90509, USA
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38
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Abstract
We have previously cloned a cDNA encoding TBP-1, a protein present in the rat spermatid manchette and outer dense fibers of the developing sperm. TBP-1 contains a heptad repeat of six-leucine zipper fingers at the amino terminus and highly conserved ATPase and DNA/RNA helicase motifs toward the carboxyl terminus. TBP-1 is one of the 20 subunits forming the 19S regulatory complex of the 26S proteasome, an ATP-dependent multisubunit protease found in most eukaryotic cells. We now report the isolation of the 26S proteasome from rat testis and sperm tail and its visualization by whole-mount electron microscopy using negative staining. The 26S proteasome from rat testis was fractionated by Sephacryl S-400/Mono-Q chromatography using homogenates suspended in a 10% glycerol-supplemented buffer. Chromatographic fractions were analyzed by immunoblotting using a specific anti-TBP-1 serum. During the purification of Sak57, a keratin filament present in outer dense fibers from epididymal sperm, we detected a substantial amount of 26S proteasomes. Intact 26S proteasomes from rat testis display a rod-shaped particles about 45 nm in length and 11-17 nm in diameter. Each particle consists of a 20S barrel-shaped component formed by four rings (alphabetabetaalpha), capped by two polar 19S regulatory complexes, each identified by an element known as the "Chinese dragon head motif". TBP-1 is an ATPase-containing subunit of the 19S regulatory cap. Rat sperm preparations displayed both dissociated 26S proteasomes and Sak57 filaments. We hypothesize that 26S proteasomes in the perinuclear-arranged manchette are in a suitable location for recognition, sequestration, and degradation of accumulating ubiquitin-conjugated somatic and transient testis-specific histones during spermiogenesis. In the sperm tail, the 26S proteasome may have a role in the remodeling of the outer dense fibers and other tail components during epididymal transit.
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Affiliation(s)
- K Mochida
- Department of Cell Biology and Anatomical Sciences, The City University of New York Medical School, New York, NY 10031, USA
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39
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Kingsbury DJ, Griffin TA, Colbert RA. Novel propeptide function in 20 S proteasome assembly influences beta subunit composition. J Biol Chem 2000; 275:24156-62. [PMID: 10816564 DOI: 10.1074/jbc.m001742200] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The assembly of eukaryotic 20 S proteasomes involves the formation of half-proteasomes where precursor beta-type subunits gather in position on an alpha-subunit ring, followed by the association of two half-proteasomes and beta-subunit processing. In vertebrates three additional beta-subunits (beta1i/LMP2, beta2i/MECL1, and beta5i/LMP7) can be synthesized and substituted for constitutive homologues (beta1/delta, beta2/Z, and beta5/X) to yield immunoproteasomes, which are important for generating certain antigenic peptides. We have shown previously that when all six beta-subunits are present, cooperative assembly mechanisms limit the diversity of proteasome populations. Specifically, LMP7 is incorporated preferentially over X into preproteasomes containing LMP2 and MECL1. We show here that the LMP7 propeptide is responsible for this preferential incorporation, and it also enables LMP7 to incorporate into proteasomes containing delta and Z. In contrast, the X propeptide restricts incorporation to proteasomes with delta and Z. Furthermore, we demonstrate that the LMP7 propeptide can function in trans when expressed on LMP2, and that its NH(2)-terminal and mid-regions are particularly critical for function. In addition to identifying a novel propeptide function, our results raise the possibility that one consequence of LMP7 incorporation into both immunoproteasomes and delta/Z proteasomes may be to increase the diversity of antigenic peptides that can be generated.
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Affiliation(s)
- D J Kingsbury
- William S. Rowe Division of Rheumatology, Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
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40
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Voges D, Zwickl P, Baumeister W. The 26S proteasome: a molecular machine designed for controlled proteolysis. Annu Rev Biochem 2000; 68:1015-68. [PMID: 10872471 DOI: 10.1146/annurev.biochem.68.1.1015] [Citation(s) in RCA: 1377] [Impact Index Per Article: 57.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In eukaryotic cells, most proteins in the cytosol and nucleus are degraded via the ubiquitin-proteasome pathway. The 26S proteasome is a 2.5-MDa molecular machine built from approximately 31 different subunits, which catalyzes protein degradation. It contains a barrel-shaped proteolytic core complex (the 20S proteasome), capped at one or both ends by 19S regulatory complexes, which recognize ubiquitinated proteins. The regulatory complexes are also implicated in unfolding and translocation of ubiquitinated targets into the interior of the 20S complex, where they are degraded to oligopeptides. Structure, assembly and enzymatic mechanism of the 20S complex have been elucidated, but the functional organization of the 19S complex is less well understood. Most subunits of the 19S complex have been identified, however, specific functions have been assigned to only a few. A low-resolution structure of the 26S proteasome has been obtained by electron microscopy, but the precise arrangement of subunits in the 19S complex is unclear.
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Affiliation(s)
- D Voges
- Max-Planck-Institut für Biochemie, Martinsried, Germany
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41
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Hölzl H, Kapelari B, Kellermann J, Seemüller E, Sümegi M, Udvardy A, Medalia O, Sperling J, Müller SA, Engel A, Baumeister W. The regulatory complex of Drosophila melanogaster 26S proteasomes. Subunit composition and localization of a deubiquitylating enzyme. J Cell Biol 2000; 150:119-30. [PMID: 10893261 PMCID: PMC2185576 DOI: 10.1083/jcb.150.1.119] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2000] [Accepted: 05/30/2000] [Indexed: 01/08/2023] Open
Abstract
Drosophila melanogaster embryos are a source for homogeneous and stable 26S proteasomes suitable for structural studies. For biochemical characterization, purified 26S proteasomes were resolved by two-dimensional (2D) gel electrophoresis and subunits composing the regulatory complex (RC) were identified by amino acid sequencing and immunoblotting, before corresponding cDNAs were sequenced. 17 subunits from Drosophila RCs were found to have homologues in the yeast and human RCs. An additional subunit, p37A, not yet described in RCs of other organisms, is a member of the ubiquitin COOH-terminal hydrolase family (UCH). Analysis of EM images of 26S proteasomes-UCH-inhibitor complexes allowed for the first time to localize one of the RC's specific functions, deubiquitylating activity. The masses of 26S proteasomes with either one or two attached RCs were determined by scanning transmission EM (STEM), yielding a mass of 894 kD for a single RC. This value is in good agreement with the summed masses of the 18 identified RC subunits (932 kD), indicating that the number of subunits is complete.
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MESH Headings
- Animals
- Drosophila melanogaster/enzymology
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Embryo, Nonmammalian/enzymology
- Macromolecular Substances
- Microscopy, Electron, Scanning Transmission
- Models, Molecular
- Molecular Sequence Data
- Molecular Weight
- Peptide Hydrolases/chemistry
- Peptide Hydrolases/genetics
- Peptide Hydrolases/isolation & purification
- Peptide Hydrolases/ultrastructure
- Proteasome Endopeptidase Complex
- Protein Structure, Tertiary
- Sequence Analysis, DNA
- Sequence Analysis, Protein
- Sequence Homology, Amino Acid
- Thiolester Hydrolases/genetics
- Thiolester Hydrolases/metabolism
- Ubiquitin Thiolesterase
- Ubiquitins/metabolism
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Affiliation(s)
- Harald Hölzl
- Max-Planck-Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Barbara Kapelari
- Max-Planck-Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Josef Kellermann
- Max-Planck-Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Erika Seemüller
- Max-Planck-Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Máté Sümegi
- Biological Research Center of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Andor Udvardy
- Biological Research Center of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Ohad Medalia
- Department of Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Joseph Sperling
- Department of Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shirley A. Müller
- Maurice E. Müller Institute, Biocenter, University of Basel, CH-4056 Basel, Switzerland
| | - Andreas Engel
- Maurice E. Müller Institute, Biocenter, University of Basel, CH-4056 Basel, Switzerland
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42
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McCutchen-Maloney SL, Matsuda K, Shimbara N, Binns DD, Tanaka K, Slaughter CA, DeMartino GN. cDNA cloning, expression, and functional characterization of PI31, a proline-rich inhibitor of the proteasome. J Biol Chem 2000; 275:18557-65. [PMID: 10764772 DOI: 10.1074/jbc.m001697200] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The primary structure of PI31, a protein inhibitor of the 20 S proteasome, was deduced by cDNA cloning and sequencing. The human protein has a calculated molecular weight of 29,792, a value in excellent accord with 31,000, as estimated by SDS-polyacrylamide gel electrophoresis for purified bovine PI31, and is not similar to any other protein in current data bases. PI31 is a proline-rich protein, particularly within its carboxyl-terminal half where 26% of the amino acids are proline. Wild-type PI31 and various truncation mutants were expressed in Escherichia coli and purified to homogeneity. Recombinant wild-type PI31 displayed structural and functional properties similar to those of PI31 purified from bovine red blood cells and inhibited the hydrolysis of protein and peptide substrates by the 20 S proteasome. Analysis of truncation mutants demonstrated that proteasome inhibition was conferred by the carboxyl-terminal proline-rich domain of PI31, which appears to have an extended secondary structure. Inhibition of the 20 S proteasome by PI31 involved formation a proteasome-PI31 complex. In addition to its direct inhibition of the 20 S proteasome, PI31 inhibited the activation of the proteasome by each of two proteasome regulatory proteins, PA700 and PA28. These results suggest that PI31 plays an important role in control of proteasome function, including that in ubiquitin-dependent pathways of protein degradation.
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Affiliation(s)
- S L McCutchen-Maloney
- Department of Physiology, The Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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43
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Abstract
There are two immune responses in vertebrates: humoral immunity is mediated by circulating antibodies, whereas cytotoxic T lymphocytes (CTL) confer cellular immunity. CTL lyse infected cells upon recognition of cell-surface MHC Class I molecules complexed with foreign peptides. The displayed peptides are produced in the cytosol by degradation of host proteins or proteins from intracellular pathogens that might be present. Proteasomes are cylindrical multisubunit proteases that generate many of the peptides eventually transferred to the cell surface for immune surveillance. In mammalian proteasomes, six active sites face a central chamber. As this chamber is sealed off from the enzyme's surface, there must be mechanisms to promote entry of substrates. Two protein complexes have been found to bind the ends of the proteasome and activate it. One of the activators is the 19 S regulatory complex of the 26 S proteasome; the other activator is '11 S REG' [Dubiel, Pratt, Ferrell and Rechsteiner (1992) J. Biol. Chem. 267, 22369-22377] or 'PA28' [Ma, Slaughter and DeMartino (1992) J. Biol. Chem. 267, 10515-10523]. During the past 7 years, our understanding of the structure of REG molecules has increased significantly, but much less is known about their biological functions. There are three REG subunits, namely alpha, beta and gamma. Recombinant REGalpha forms a ring-shaped heptamer of known crystal structure. 11 S REG is a heteroheptamer of alpha and beta subunits. REGgamma is also presumably a heptameric ring, and it is found in the nuclei of the nematode work Caenorhabditis elegans and higher organisms, where it may couple proteasomes to other nuclear components. REGalpha and REGbeta, which are abundant in vertebrate immune tissues, are located mostly in the cytoplasm. Synthesis of REG alpha and beta subunits is induced by interferon-gamma, and this has led to the prevalent hypothesis that REG alpha/beta hetero-oligomers play an important role in Class I antigen presentation. In the present review we focus on the structural properties of REG molecules and on the evidence that REGalpha/beta functions in the Class I immune response.
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44
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Starkova NN, Koroleva EP, Rotanova TV. Intracellular proteolysis: Signals of selective protein degradation. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2000. [DOI: 10.1007/bf02759152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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45
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Takeuchi J, Fujimuro M, Yokosawa H, Tanaka K, Toh-e A. Rpn9 is required for efficient assembly of the yeast 26S proteasome. Mol Cell Biol 1999; 19:6575-84. [PMID: 10490597 PMCID: PMC84627 DOI: 10.1128/mcb.19.10.6575] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have isolated the RPN9 gene by two-hybrid screening with, as bait, RPN10 (formerly SUN1), which encodes a multiubiquitin chain receptor residing in the regulatory particle of the 26S proteasome. Rpn9 is a nonessential subunit of the regulatory particle of the 26S proteasome, but the deletion of this gene results in temperature-sensitive growth. At the restrictive temperature, the Deltarpn9 strain accumulated multiubiquitinated proteins, indicating that the RPN9 function is needed for the 26S proteasome activity at a higher temperature. We analyzed the proteasome fractions separated by glycerol density gradient centrifugation by native polyacrylamide gel electrophoresis and found that a smaller amount of the 26S proteasome was produced in the Deltarpn9 cells and that the 26S proteasome was shifted to lighter fractions than expected. The incomplete proteasome complexes were found to accumulate in the Deltarpn9 cells. Furthermore, Rpn10 was not detected in the fractions containing proteasomes of the Deltarpn9 cells. These results indicate that Rpn9 is needed for incorporating Rpn10 into the 26S proteasome and that Rpn9 participates in the assembly and/or stability of the 26S proteasome.
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Affiliation(s)
- J Takeuchi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Tokyo 113-0033, Japan
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46
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Zwickl P, Voges D, Baumeister W. The proteasome: a macromolecular assembly designed for controlled proteolysis. Philos Trans R Soc Lond B Biol Sci 1999; 354:1501-11. [PMID: 10582236 PMCID: PMC1692663 DOI: 10.1098/rstb.1999.0494] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In eukaryotic cells, the vast majority of proteins in the cytosol and nucleus are degraded via the proteasome-ubiquitin pathway. The 26S proteasome is a huge protein degradation machine of 2.5 MDa, built of approximately 35 different subunits. It contains a proteolytic core complex, the 20S proteasome and one or two 19S regulatory complexes which associate with the termini of the barrel-shaped 20S core. The 19S regulatory complex serves to recognize ubiquitylated target proteins and is implicated to have a role in their unfolding and translocation into the interior of the 20S complex where they are degraded into oligopeptides. While much progress has been made in recent years in elucidating the structure, assembly and enzymatic mechanism of the 20S complex, our knowledge of the functional organization of the 19S regulator is rather limited. Most of its subunits have been identified, but specific functions can be assigned to only a few of them.
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Affiliation(s)
- P Zwickl
- Max-Planck-Institute for Biochemistry, Martinsried, Germany
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47
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Makino Y, Yoshida T, Yogosawa S, Tanaka K, Muramatsu M, Tamura TA. Multiple mammalian proteasomal ATPases, but not proteasome itself, are associated with TATA-binding protein and a novel transcriptional activator, TIP120. Genes Cells 1999; 4:529-39. [PMID: 10526239 DOI: 10.1046/j.1365-2443.1999.00277.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND SUG1 belongs to proteasomal ATPase. Previous studies have demonstrated that SUG1 is associated with TBP. It is assumed to be involved in transcriptional regulation in addition to proteolysis. In this study, we investigated the association of mammalian SUG1 with TBP in more detail. RESULTS Pull-down experiments with TBP revealed multiple TBP-interacting proteins (TIPs) that were recovered dependent upon the presence of C-terminal conserved domain of TBP. By 2-D electrophoresis, we identified SUG1 in TIPs. By using far-Western analysis, we identified two proteins that could directly bind to TBP: SUG1 and another proteasomal ATPase (S4). Protein microsequencing and Western blotting identified all the remaining proteasomal ATPases (MSS1, TBP1, TBP7, and SUG2) in the TIP preparations. We present evidence that TBP and at least SUG1, MSS1, and S4 form a complex in the cell. However, no evidence of association of TBP with the 26S proteasome or its 19S regulatory unit was obtained. The molecular mass of the TBP/ATPases-complex, which also included a novel transcription regulatory factor, TIP120, was estimated to be approximately 800 kDa. CONCLUSION These results suggest that there is a novel multisubunit complex containing TBP and proteasomal ATPases. Based on our findings, we hypothesize that proteasomal ATPases are involved in transcriptional regulation in addition to proteolysis.
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Affiliation(s)
- Y Makino
- Department of Biology, Faculty of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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48
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Uehara T, Matsuno J, Kaneko M, Nishiya T, Fujimuro M, Yokosawa H, Nomura Y. Transient nuclear factor kappaB (NF-kappaB) activation stimulated by interleukin-1beta may be partly dependent on proteasome activity, but not phosphorylation and ubiquitination of the IkappaBalpha molecule, in C6 glioma cells. Regulation of NF-kappaB linked to chemokine production. J Biol Chem 1999; 274:15875-82. [PMID: 10336492 DOI: 10.1074/jbc.274.22.15875] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously reported that several stresses can induce cytokine-induced neutrophil chemoattractant expression in a nuclear factor kappaB (NF-kappaB)-dependent manner. In this study, we focused further on the regulation of NF-kappaB. The activation of NF-kappaB and the subsequent cytokine-induced neutrophil chemoattractant induction in response to interleukin-1beta (IL-1beta) were inhibited by proteasome inhibitors, MG132 and proteasome inhibitor I. Translocation of NF-kappaB into nuclei occurs by the phosphorylation, multi-ubiquitination, and degradation of IkappaBalpha, a regulatory protein of NF-kappaB. Nascent IkappaBalpha began to degrade 5 min after treatment with IL-1beta and disappeared completely after 15 min. However, IkappaBalpha returned to basal levels after 45-60 min. Interestingly, resynthesized IkappaBalpha was already phosphorylated at Ser-32. These results suggest that 1) the upstream signals are still activated, although the translocation of NF-kappaB peaks at 15 min; and 2) the regulated protein(s) acts downstream of IkappaBalpha phosphorylation. Western blotting showed that the resynthesized and phosphorylated IkappaB molecules were also upward-shifted by multi-ubiquitination in response to IL-1beta treatment. On the other hand, ATP-dependent Leu-Leu-Val-Tyr cleaving activity transiently increased, peaked at 15 min, and then decreased to basal levels at 60 min. Furthermore, the cytosolic fraction that was stimulated by IL-1beta for 15 min, but not for 0 and 60 min, could degrade phosphorylated and multi-ubiquitinated IkappaBalpha. These results indicate that the transient translocation of NF-kappaB in response to IL-1beta may be partly dependent on transient proteasome activation.
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Affiliation(s)
- T Uehara
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
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49
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Wigley WC, Fabunmi RP, Lee MG, Marino CR, Muallem S, DeMartino GN, Thomas PJ. Dynamic association of proteasomal machinery with the centrosome. J Cell Biol 1999; 145:481-90. [PMID: 10225950 PMCID: PMC2185077 DOI: 10.1083/jcb.145.3.481] [Citation(s) in RCA: 409] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Although the number of pathologies known to arise from the inappropriate folding of proteins continues to grow, mechanisms underlying the recognition and ultimate disposition of misfolded polypeptides remain obscure. For example, how and where such substrates are identified and processed is unknown. We report here the identification of a specific subcellular structure in which, under basal conditions, the 20S proteasome, the PA700 and PA28 (700- and 180-kD proteasome activator complexes, respectively), ubiquitin, Hsp70 and Hsp90 (70- and 90-kD heat shock protein, respectively) concentrate in HEK 293 and HeLa cells. The structure is perinuclear, surrounded by endoplasmic reticulum, adjacent to the Golgi, and colocalizes with gamma-tubulin, an established centrosomal marker. Density gradient fractions containing purified centrosomes are enriched in proteasomal components and cell stress chaperones. The centrosome-associated structure enlarges in response to inhibition of proteasome activity and the level of misfolded proteins. For example, folding mutants of CFTR form large inclusions which arise from the centrosome upon inhibition of proteasome activity. At high levels of misfolded protein, the structure not only expands but also extensively recruits the cytosolic pools of ubiquitin, Hsp70, PA700, PA28, and the 20S proteasome. Thus, the centrosome may act as a scaffold, which concentrates and recruits the systems which act as censors and modulators of the balance between folding, aggregation, and degradation.
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Affiliation(s)
- W C Wigley
- Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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50
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Stenoien DL, Cummings CJ, Adams HP, Mancini MG, Patel K, DeMartino GN, Marcelli M, Weigel NL, Mancini MA. Polyglutamine-expanded androgen receptors form aggregates that sequester heat shock proteins, proteasome components and SRC-1, and are suppressed by the HDJ-2 chaperone. Hum Mol Genet 1999; 8:731-41. [PMID: 10196362 DOI: 10.1093/hmg/8.5.731] [Citation(s) in RCA: 340] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal bulbar muscular atrophy is a neurodegenerative disorder caused by a polyglutamine expansion in the androgen receptor (AR). We show in transiently transfected HeLa cells that an AR containing 48 glutamines (ARQ48) accumulates in a hormone-dependent manner in both cytoplasmic and nuclear aggregates. Electron microscopy reveals both types of aggregates to have a similar ultrastructure. ARQ48 aggregates sequester mitochondria and steroid receptor coactivator 1 and stain positively for NEDD8, Hsp70, Hsp90 and HDJ-2/HSDJ. Co-expression of HDJ-2/HSDJ significantly represses aggregate formation. ARQ48 aggregates also label with antibodies recognizing the PA700 proteasome caps but not 20S core particles. These results suggest that ARQ48 accumulates due to protein misfolding and a breakdown in proteolytic processing. Furthermore, the homeostatic disturbances associated with aggregate formation may affect normal cell function.
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Affiliation(s)
- D L Stenoien
- Department of Cell Biology, Baylor College of Medicine and VA Medical Center, One Baylor Plaza, Houston, TX 77030, USA
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