1
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Inholz K, Bader U, Mundt S, Basler M. The Significant Role of PA28αβ in CD8 + T Cell-Mediated Graft Rejection Contrasts with Its Negligible Impact on the Generation of MHC-I Ligands. Int J Mol Sci 2024; 25:5649. [PMID: 38891837 PMCID: PMC11172216 DOI: 10.3390/ijms25115649] [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: 04/10/2024] [Revised: 05/19/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
The proteasome generates the majority of peptides presented on MHC class I molecules. The cleavage pattern of the proteasome has been shown to be changed via the proteasome activator (PA)28 alpha beta (PA28αβ). In particular, several immunogenic peptides have been reported to be PA28αβ-dependent. In contrast, we did not observe a major impact of PA28αβ on the generation of different major histocompatibility complex (MHC) classI ligands. PA28αβ-knockout mice infected with the lymphocytic choriomeningitis virus (LCMV) or vaccinia virus showed a normal cluster of differentiation (CD) 8 response and viral clearance. However, we observed that the adoptive transfer of wild-type cells into PA28αβ-knockout mice led to graft rejection, but not vice versa. Depletion experiments showed that the observed rejection was mediated by CD8+ cytotoxic T cells. These data indicate that PA28αβ might be involved in the development of the CD8+ T cell repertoire in the thymus. Taken together, our data suggest that PA28αβ is a crucial factor determining T cell selection and, therefore, impacts graft acceptance.
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Affiliation(s)
- Katharina Inholz
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, 8280 Kreuzlingen, Switzerland;
- Division of Immunology, Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Ulrika Bader
- Division of Immunology, Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Sarah Mundt
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
| | - Michael Basler
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, 8280 Kreuzlingen, Switzerland;
- Division of Immunology, Department of Biology, University of Konstanz, 78464 Konstanz, Germany
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2
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Cascio P. PA28γ, the ring that makes tumors invisible to the immune system? Biochimie 2024:S0300-9084(24)00078-6. [PMID: 38631454 DOI: 10.1016/j.biochi.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/29/2024] [Accepted: 04/12/2024] [Indexed: 04/19/2024]
Abstract
PA28γ is a proteasomal interactor whose main and most known function is to stimulate the hydrolytic activity of the 20 S proteasome independently of ubiquitin and ATP. Unlike its two paralogues, PA28α and PA28β, PA28γ is largely present in the nuclear compartment and plays pivotal functions in important pathways such as cellular division, apoptosis, neoplastic transformation, chromatin structure and organization, fertility, lipid metabolism, and DNA repair mechanisms. Although it is known that a substantial fraction of PA28γ is found in the cell in a free form (i.e. not associated with 20 S), almost all of the studies so far have focused on its ability to modulate proteasomal enzymatic activities. In this respect, the ability of PA28γ to strongly stimulate degradation of proteins, especially if intrinsically disordered and therefore devoid of three-dimensional tightly folded structure, appears to be the main molecular mechanism underlying its multiple biological effects. Initial studies, conducted more than 20 years ago, came to the conclusion that among the many biological functions of PA28γ, the immunological ones were rather limited and circumscribed. In this review, we focus on recent evidence showing that PA28γ fulfills significant functions in cell-mediated acquired immunity, with a particular role in attenuating MHC class I antigen presentation, especially in relation to neoplastic transformation and autoimmune diseases.
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Affiliation(s)
- Paolo Cascio
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, 10095, Grugliasco, Turin, Italy.
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3
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Thomas T, Salcedo-Tacuma D, Smith DM. Structure, Function, and Allosteric Regulation of the 20S Proteasome by the 11S/PA28 Family of Proteasome Activators. Biomolecules 2023; 13:1326. [PMID: 37759726 PMCID: PMC10526260 DOI: 10.3390/biom13091326] [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: 07/17/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
The proteasome, a complex multi-catalytic protease machinery, orchestrates the protein degradation essential for maintaining cellular homeostasis, and its dysregulation also underlies many different types of diseases. Its function is regulated by many different mechanisms that encompass various factors such as proteasome activators (PAs), adaptor proteins, and post-translational modifications. This review highlights the unique characteristics of proteasomal regulation through the lens of a distinct family of regulators, the 11S, REGs, or PA26/PA28. This ATP-independent family, spanning from amoebas to mammals, exhibits a common architectural structure; yet, their cellular biology and criteria for protein degradation remain mostly elusive. We delve into their evolution and cellular biology, and contrast their structure and function comprehensively, emphasizing the unanswered questions regarding their regulatory mechanisms and broader roles in proteostasis. A deeper understanding of these processes will illuminate the roles of this regulatory family in biology and disease, thus contributing to the advancement of therapeutic strategies.
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Affiliation(s)
- Taylor Thomas
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Drive, Morgantown, WV 26506, USA
| | - David Salcedo-Tacuma
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Drive, Morgantown, WV 26506, USA
| | - David M. Smith
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Drive, Morgantown, WV 26506, USA
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, USA
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4
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Kriachkov VA, Gotmanova NN, Tashlitsky VN, Bacheva AV. Brain-Derived 11S Regulator (PA28αβ) Promotes Proteasomal Hydrolysis of Elongated Oligoglutamine-Containing Peptides. Int J Mol Sci 2023; 24:13275. [PMID: 37686081 PMCID: PMC10487437 DOI: 10.3390/ijms241713275] [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: 07/14/2023] [Revised: 08/08/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
Proteins with extended polyglutamine regions are associated with several neurodegenerative disorders, including Huntington's disease. Intracellular proteolytic processing of these proteins is not well understood. In particular, it is unclear whether long polyglutamine fragments resulting from the proteolysis of these proteins can be potentially cleaved by the proteasome. Here, we studied the susceptibility of the glutamine-glutamine bond to proteolysis by the proteasome using oligoglutamine-containing peptides with a fluorophore/quencher pair. We found that the addition of the 11S proteasomal regulator (also known as PA28) significantly accelerated the hydrolysis of oligoglutamine-containing peptides by the 20S proteasome. Unexpectedly, a similar effect was observed for the 26S proteasome in the presence of the 11S regulator. LC/MS data revealed that the hydrolysis of our peptides with both 20S and 26S proteasomes leads to N-terminal fragments containing two or three glutamine residues and that the hydrolysis site does not change after the addition of the 11S regulator. This was confirmed by the docking experiment, which shows that the preferred hydrolysis site is located after the second/third glutamine residue. Inhibitory analysis revealed that trypsin-like specificity is mainly responsible for the proteasomal hydrolysis of the glutamine-glutamine bond. Together, our results indicate that both 20S and 26S proteasomes are capable of degrading the N-terminal part of oligoglutamine fragments, while the 11S regulator significantly accelerates the hydrolysis without changing its specificity. This data suggests that proteasome activity may be enhanced in relation to polyglutamine substrates present in neurons in the early stages of polyglutamine disorders.
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Affiliation(s)
- Viacheslav A. Kriachkov
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC 3010, Australia;
| | - Natalia N. Gotmanova
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (N.N.G.); (V.N.T.)
| | - Vadim N. Tashlitsky
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (N.N.G.); (V.N.T.)
| | - Anna V. Bacheva
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (N.N.G.); (V.N.T.)
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5
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Targeting immunoproteasome in neurodegeneration: A glance to the future. Pharmacol Ther 2023; 241:108329. [PMID: 36526014 DOI: 10.1016/j.pharmthera.2022.108329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022]
Abstract
The immunoproteasome is a specialized form of proteasome equipped with modified catalytic subunits that was initially discovered to play a pivotal role in MHC class I antigen processing and immune system modulation. However, over the last years, this proteolytic complex has been uncovered to serve additional functions unrelated to antigen presentation. Accordingly, it has been proposed that immunoproteasome synergizes with canonical proteasome in different cell types of the nervous system, regulating neurotransmission, metabolic pathways and adaptation of the cells to redox or inflammatory insults. Hence, studying the alterations of immunoproteasome expression and activity is gaining research interest to define the dynamics of neuroinflammation as well as the early and late molecular events that are likely involved in the pathogenesis of a variety of neurological disorders. Furthermore, these novel functions foster the perspective of immunoproteasome as a potential therapeutic target for neurodegeneration. In this review, we provide a brain and retina-wide overview, trying to correlate present knowledge on structure-function relationships of immunoproteasome with the variety of observed neuro-modulatory functions.
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6
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Sbardella D, Tundo GR, Mecchia A, Palumbo C, Atzori MG, Levati L, Boccaccini A, Caccuri AM, Cascio P, Lacal PM, Graziani G, Varano M, Coletta M, Parravano M. A novel and atypical NF-KB pro-inflammatory program regulated by a CamKII-proteasome axis is involved in the early activation of Muller glia by high glucose. Cell Biosci 2022; 12:108. [PMID: 35842713 PMCID: PMC9287993 DOI: 10.1186/s13578-022-00839-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 06/28/2022] [Indexed: 11/29/2022] Open
Abstract
Background Diabetic retinopathy (DR) is a microvascular complication of diabetes with a heavy impact on the quality of life of subjects and with a dramatic burden for health and economic systems on a global scale. Although the pathogenesis of DR is largely unknown, several preclinical data have pointed out to a main role of Muller glia (MG), a cell type which spans across the retina layers providing nourishment and support for Retina Ganglion Cells (RGCs), in sensing hyper-glycemia and in acquiring a pro-inflammatory polarization in response to this insult. Results By using a validated experimental model of DR in vitro, rMC1 cells challenged with high glucose, we uncovered the induction of an early (within minutes) and atypical Nuclear Factor-kB (NF-kB) signalling pathway regulated by a calcium-dependent calmodulin kinase II (CamKII)-proteasome axis. Phosphorylation of proteasome subunit Rpt6 (at Serine 120) by CamKII stimulated the accelerated turnover of IkBα (i.e., the natural inhibitor of p65-50 transcription factor), regardless of the phosphorylation at Serine 32 which labels canonical NF-kB signalling. This event allowed the p65-p50 heterodimer to migrate into the nucleus and to induce transcription of IL-8, Il-1β and MCP-1. Pharmacological inhibition of CamKII as well as proteasome inhibition stopped this pro-inflammatory program, whereas introduction of a Rpt6 phospho-dead mutant (Rpt6-S120A) stimulated a paradoxical effect on NF-kB probably through the activation of a compensatory mechanism which may involve phosphorylation of 20S α4 subunit. Conclusions This study introduces a novel pathway of MG activation by high glucose and casts some light on the biological relevance of proteasome post-translational modifications in modulating pathways regulated through targeted proteolysis. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-022-00839-x. High glucose quickly induces an atypical NF-kB pro-inflammatory program. CamKII phosphorylation of Rpt6 subunit of the proteasome stimulates IkBα turnover and p65-p50 release. Inhibition of either CamkII or proteasome blocks this pathway.
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7
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Anderson RT, Bradley TA, Smith DM. Hyperactivation of the proteasome in Caenorhabditis elegans protects against proteotoxic stress and extends lifespan. J Biol Chem 2022; 298:102415. [PMID: 36007615 PMCID: PMC9486566 DOI: 10.1016/j.jbc.2022.102415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Virtually all age-related neurodegenerative diseases (NDs) can be characterized by the accumulation of proteins inside and outside the cell that are thought to significantly contribute to disease pathogenesis. One of the cell’s primary systems for the degradation of misfolded/damaged proteins is the ubiquitin proteasome system (UPS), and its impairment is implicated in essentially all NDs. Thus, upregulating this system to combat NDs has garnered a great deal of interest in recent years. Various animal models have focused on stimulating 26S activity and increasing 20S proteasome levels, but thus far, none have targeted intrinsic activation of the 20S proteasome itself. Therefore, we constructed an animal model that endogenously expresses a hyperactive, open gate proteasome in Caenorhabditis elegans. The gate-destabilizing mutation that we introduced into the nematode germline yielded a viable nematode population with enhanced proteasomal activity, including peptide, unstructured protein, and ubiquitin-dependent degradation activities. We determined these nematodes showed a significantly increased lifespan and substantial resistance to oxidative and proteotoxic stress but a significant decrease in fecundity. Our results show that introducing a constitutively active proteasome into a multicellular organism is feasible and suggests targeting the proteasome gating mechanism as a valid approach for future age-related disease research efforts in mammals.
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Affiliation(s)
- Raymond T Anderson
- Department of Biochemistry, West Virginia University School of Medicine, 64 Medical Center Dr., Morgantown, WV 26506
| | - Thomas A Bradley
- Department of Biochemistry, West Virginia University School of Medicine, 64 Medical Center Dr., Morgantown, WV 26506
| | - David M Smith
- Department of Biochemistry, West Virginia University School of Medicine, 64 Medical Center Dr., Morgantown, WV 26506.
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8
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Atomic resolution Cryo-EM structure of human proteasome activator PA28γ. Int J Biol Macromol 2022; 219:500-507. [PMID: 35932807 DOI: 10.1016/j.ijbiomac.2022.07.246] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 07/18/2022] [Accepted: 07/31/2022] [Indexed: 11/21/2022]
Abstract
The PA28 family proteasome activators play important roles in regulating proteasome activities. Though the three paralogs (PA28α, PA28β, and PA28γ) are similar in terms of primary sequence, they show significant difference in expression pattern, cellular localization and most importantly, biological functions. While PA28αβ is responsible for promoting peptidase activity of proteasome to facilitate MHC-I antigen processing, but unable to promote protein degradation, PA28γ is well-known to not only promote peptidase activity, but also proteolytic activity of proteasome. However, why this paralog has the unique function remains elusive. Previous structural studies have mainly focused on mammalian PA28α, PA28β and PA28αβ heptamers, while structural studies on mammalian PA28γ of atomic resolution are still absent to date. In the present work, we determined the Cryo-EM structure of the human PA28γ heptamer at atomic resolution, revealing interesting unique structural features that may hint our understanding the functional mechanisms of this proteasome activator.
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9
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Allostery Modulates Interactions between Proteasome Core Particles and Regulatory Particles. Biomolecules 2022; 12:biom12060764. [PMID: 35740889 PMCID: PMC9221237 DOI: 10.3390/biom12060764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/26/2022] [Accepted: 05/28/2022] [Indexed: 01/27/2023] Open
Abstract
Allostery-regulation at distant sites is a key concept in biology. The proteasome exhibits multiple forms of allosteric regulation. This regulatory communication can span a distance exceeding 100 Ångstroms and can modulate interactions between the two major proteasome modules: its core particle and regulatory complexes. Allostery can further influence the assembly of the core particle with regulatory particles. In this focused review, known and postulated interactions between these proteasome modules are described. Allostery may explain how cells build and maintain diverse populations of proteasome assemblies and can provide opportunities for therapeutic interventions.
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10
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Induction by Phenobarbital of Phase I and II Xenobiotic-Metabolizing Enzymes in Bovine Liver: An Overall Catalytic and Immunochemical Characterization. Int J Mol Sci 2022; 23:ijms23073564. [PMID: 35408925 PMCID: PMC8998613 DOI: 10.3390/ijms23073564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/14/2022] [Accepted: 03/21/2022] [Indexed: 12/15/2022] Open
Abstract
In cattle, phenobarbital (PB) upregulates target drug-metabolizing enzyme (DME) mRNA levels. However, few data about PB's post-transcriptional effects are actually available. This work provides the first, and an almost complete, characterization of PB-dependent changes in DME catalytic activities in bovine liver using common probe substrates and confirmatory immunoblotting investigations. As expected, PB increased the total cytochrome P450 (CYP) content and the extent of metyrapone binding; moreover, an augmentation of protein amounts and related enzyme activities was observed for known PB targets such as CYP2B, 2C, and 3A, but also CYP2E1. However, contradictory results were obtained for CYP1A, while a decreased catalytic activity was observed for flavin-containing monooxygenases 1 and 3. The barbiturate had no effect on the chosen hydrolytic and conjugative DMEs. For the first time, we also measured the 26S proteasome activity, and the increase observed in PB-treated cattle would suggest this post-translational event might contribute to cattle DME regulation. Overall, this study increased the knowledge of cattle hepatic drug metabolism, and further confirmed the presence of species differences in DME expression and activity between cattle, humans, and rodents. This reinforced the need for an extensive characterization and understanding of comparative molecular mechanisms involved in expression, regulation, and function of DMEs.
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11
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Functional Differences between Proteasome Subtypes. Cells 2022; 11:cells11030421. [PMID: 35159231 PMCID: PMC8834425 DOI: 10.3390/cells11030421] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 12/30/2022] Open
Abstract
Four proteasome subtypes are commonly present in mammalian tissues: standard proteasomes, which contain the standard catalytic subunits β1, β2 and β5; immunoproteasomes containing the immuno-subunits β1i, β2i and β5i; and two intermediate proteasomes, containing a mix of standard and immuno-subunits. Recent studies revealed the expression of two tissue-specific proteasome subtypes in cortical thymic epithelial cells and in testes: thymoproteasomes and spermatoproteasomes. In this review, we describe the mechanisms that enable the ATP- and ubiquitin-dependent as well as the ATP- and ubiquitin-independent degradation of proteins by the proteasome. We focus on understanding the role of the different proteasome subtypes in maintaining protein homeostasis in normal physiological conditions through the ATP- and ubiquitin-dependent degradation of proteins. Additionally, we discuss the role of each proteasome subtype in the ATP- and ubiquitin-independent degradation of disordered proteins. We also discuss the role of the proteasome in the generation of peptides presented by MHC class I molecules and the implication of having different proteasome subtypes for the peptide repertoire presented at the cell surface. Finally, we discuss the role of the immunoproteasome in immune cells and its modulation as a potential therapy for autoimmune diseases.
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12
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Tripathi SC, Vedpathak D, Ostrin EJ. The Functional and Mechanistic Roles of Immunoproteasome Subunits in Cancer. Cells 2021; 10:cells10123587. [PMID: 34944095 PMCID: PMC8700164 DOI: 10.3390/cells10123587] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022] Open
Abstract
Cell-mediated immunity is driven by antigenic peptide presentation on major histocompatibility complex (MHC) molecules. Specialized proteasome complexes called immunoproteasomes process viral, bacterial, and tumor antigens for presentation on MHC class I molecules, which can induce CD8 T cells to mount effective immune responses. Immunoproteasomes are distinguished by three subunits that alter the catalytic activity of the proteasome and are inducible by inflammatory stimuli such as interferon-γ (IFN-γ). This inducible activity places them in central roles in cancer, autoimmunity, and inflammation. While accelerated proteasomal degradation is an important tumorigenic mechanism deployed by several cancers, there is some ambiguity regarding the role of immunoproteasome induction in neoplastic transformation. Understanding the mechanistic and functional relevance of the immunoproteasome provides essential insights into developing targeted therapies, including overcoming resistance to standard proteasome inhibition and immunomodulation of the tumor microenvironment. In this review, we discuss the roles of the immunoproteasome in different cancers.
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Affiliation(s)
- Satyendra Chandra Tripathi
- Department of Biochemistry, All India Institute of Medical Sciences Nagpur, Nagpur 441108, MH, India;
- Correspondence: (S.C.T.); (E.J.O.)
| | - Disha Vedpathak
- Department of Biochemistry, All India Institute of Medical Sciences Nagpur, Nagpur 441108, MH, India;
| | - Edwin Justin Ostrin
- Department of General Internal Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Correspondence: (S.C.T.); (E.J.O.)
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13
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Frayssinhes JYA, Cerruti F, Laulin J, Cattaneo A, Bachi A, Apcher S, Coux O, Cascio P. PA28γ-20S proteasome is a proteolytic complex committed to degrade unfolded proteins. Cell Mol Life Sci 2021; 79:45. [PMID: 34913092 PMCID: PMC11071804 DOI: 10.1007/s00018-021-04045-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 02/07/2023]
Abstract
PA28γ is a nuclear activator of the 20S proteasome that, unlike the 19S regulatory particle, stimulates hydrolysis of several substrates in an ATP- and ubiquitin-independent manner and whose exact biological functions and molecular mechanism of action still remain elusive. In an effort to shed light on these important issues, we investigated the stimulatory effect of PA28γ on the hydrolysis of different fluorogenic peptides and folded or denatured full-length proteins by the 20S proteasome. Importantly, PA28γ was found to dramatically enhance breakdown rates by 20S proteasomes of several naturally or artificially unstructured proteins, but not of their native, folded counterparts. Furthermore, these data were corroborated by experiments in cell lines with a nucleus-tagged myelin basic protein. Finally, mass spectrometry analysis of the products generated during proteasomal degradation of two proteins demonstrated that PA28γ does not increase, but rather decreases, the variability of peptides that are potentially suitable for MHC class I antigen presentation. These unexpected findings indicate that global stimulation of the degradation of unfolded proteins may represent a more general feature of PA28γ and suggests that this proteasomal activator might play a broader role in the pathway of protein degradation than previously believed.
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Affiliation(s)
| | - Fulvia Cerruti
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, 10095, Grugliasco, Turin, Italy
| | - Justine Laulin
- Université Paris-Saclay, Institut Gustave Roussy, Inserm, Immunologie Des Tumeurs et Immunothérapie, Villejuif, France
| | | | - Angela Bachi
- The FIRC Institute of Molecular Oncology (IFOM), 20139, Milan, Italy
| | - Sebastien Apcher
- Université Paris-Saclay, Institut Gustave Roussy, Inserm, Immunologie Des Tumeurs et Immunothérapie, Villejuif, France
| | - Olivier Coux
- Centre de Recherche de Biologie Cellulaire de Montpellier (CRBM), CNRS UMR 5237, Université de Montpellier, 1919 Route de Mende, 34293, Montpellier, France
| | - Paolo Cascio
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, 10095, Grugliasco, Turin, Italy.
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14
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Tundo GR, Sbardella D, Oddone F, Kudriaeva AA, Lacal PM, Belogurov AA, Graziani G, Marini S. At the Cutting Edge against Cancer: A Perspective on Immunoproteasome and Immune Checkpoints Modulation as a Potential Therapeutic Intervention. Cancers (Basel) 2021; 13:4852. [PMID: 34638337 PMCID: PMC8507813 DOI: 10.3390/cancers13194852] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 01/22/2023] Open
Abstract
Immunoproteasome is a noncanonical form of proteasome with enzymological properties optimized for the generation of antigenic peptides presented in complex with class I MHC molecules. This enzymatic property makes the modulation of its activity a promising area of research. Nevertheless, immunotherapy has emerged as a front-line treatment of advanced/metastatic tumors providing outstanding improvement of life expectancy, even though not all patients achieve a long-lasting clinical benefit. To enhance the efficacy of the currently available immunotherapies and enable the development of new strategies, a broader knowledge of the dynamics of antigen repertoire processing by cancer cells is needed. Therefore, a better understanding of the role of immunoproteasome in antigen processing and of the therapeutic implication of its modulation is mandatory. Studies on the potential crosstalk between proteasome modulators and immune checkpoint inhibitors could provide novel perspectives and an unexplored treatment option for a variety of cancers.
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Affiliation(s)
| | | | | | - Anna A. Kudriaeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.A.K.)
| | - Pedro M. Lacal
- Laboratory of Molecular Oncology, IDI-IRCCS, 00167 Rome, Italy;
| | - Alexey A. Belogurov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.A.K.)
- Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow, Russia
| | - Grazia Graziani
- Laboratory of Molecular Oncology, IDI-IRCCS, 00167 Rome, Italy;
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Stefano Marini
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy;
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15
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Zhan RZ, Rao L, Chen Z, Strash N, Bursac N. Loss of sarcomeric proteins via upregulation of JAK/STAT signaling underlies interferon-γ-induced contractile deficit in engineered human myocardium. Acta Biomater 2021; 126:144-153. [PMID: 33705988 DOI: 10.1016/j.actbio.2021.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 02/25/2021] [Accepted: 03/02/2021] [Indexed: 12/19/2022]
Abstract
The level of circulating interferon-γ (IFNγ) is elevated in various clinical conditions including autoimmune and inflammatory diseases, sepsis, acute coronary syndrome, and viral infections. As these conditions are associated with high risk of myocardial dysfunction, we investigated the effects of IFNγ on 3D fibrin-based engineered human cardiac tissues ("cardiobundles"). Cardiobundles were fabricated from human pluripotent stem cell-derived cardiomyocytes, exposed to 0-20 ng/ml of IFNγ on culture days 7-14, and assessed for changes in tissue structure, viability, contractile force and calcium transient generation, action potential propagation, cytokine secretion, and expression of select genes and proteins. We found that application of IFNγ induced a dose-dependent reduction in contractile force generation, deterioration of sarcomeric organization, and cardiomyocyte disarray, without significantly altering cell viability, action potential propagation, or calcium transient amplitude. At molecular level, the IFNγ-induced structural and functional deficits could be attributed to altered balance of pro- and anti-inflammatory cytokines, upregulation of JAK/STAT signaling pathway (JAK1, JAK2, and STAT1), and reduced expression of myosin heavy chain, myosin light chain-2v, and sarcomeric α-actinin. Application of clinically used JAK/STAT inhibitors, tofacitinib and baricitinib, fully prevented IFNγ-induced cardiomyopathy, confirming the critical roles of this signaling pathway in inflammatory cardiac disease. Taken together, our in vitro studies in engineered myocardial tissues reveal direct adverse effects of pro-inflammatory cytokine IFNγ on human cardiomyocytes and establish the foundation for a potential use of cardiobundle platform in modeling of inflammatory myocardial disease and therapy. STATEMENT OF SIGNIFICANCE: Various inflammatory and autoimmune diseases including rheumatoid arthritis, sepsis, lupus erythematosus, Chagas disease, and others, as well as viral infections including H1N1 influenza and COVID-19 show increased systemic levels of a pro-inflammatory cytokine interferon-γ (IFNγ) and are associated with high risk of heart disease. Here we explored for the first time if chronically elevated levels of IFNγ can negatively affect structure and function of engineered human heart tissues in vitro. Our studies revealed IFNγ-induced deterioration of myofibrillar organization and contractile force production in human cardiomyocytes, attributed to decreased expression of multiple sarcomeric proteins and upregulation of JAK/STAT signaling pathway. FDA-approved JAK inhibitors fully blocked the adverse effects of IFNγ, suggesting a potentially effective strategy against human inflammatory cardiomyopathy.
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16
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Burris A, Waite KA, Reuter Z, Ockerhausen S, Roelofs J. Proteasome activator Blm10 levels and autophagic degradation directly impact the proteasome landscape. J Biol Chem 2021; 296:100468. [PMID: 33639167 PMCID: PMC8039559 DOI: 10.1016/j.jbc.2021.100468] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 02/12/2021] [Accepted: 02/23/2021] [Indexed: 12/09/2022] Open
Abstract
The proteasome selectively degrades proteins. It consists of a core particle (CP), which contains proteolytic active sites that can associate with different regulators to form various complexes. How these different complexes are regulated and affected by changing physiological conditions, however, remains poorly understood. In this study, we focused on the activator Blm10 and the regulatory particle (RP). In yeast, increased expression of Blm10 outcompeted RP for CP binding, which suggests that controlling the cellular levels of Blm10 can affect the relative amounts of RP-bound CP. While strong overexpression of BLM10 almost eliminated the presence of RP-CP complexes, the phenotypes this should induce were not observed. Our results show this was due to the induction of Blm10-CP autophagy under prolonged growth in YPD. Similarly, under conditions of endogenous BLM10 expression, Blm10 was degraded through autophagy as well. This suggests that reducing the levels of Blm10 allows for more CP-binding surfaces and the formation of RP-CP complexes under nutrient stress. This work provides important insights into maintaining the proteasome landscape and how protein expression levels affect proteasome function.
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Affiliation(s)
- Alicia Burris
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Kenrick A Waite
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Zachary Reuter
- Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Samuel Ockerhausen
- Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Jeroen Roelofs
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA.
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17
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Abstract
The 26S proteasome is the most complex ATP-dependent protease machinery, of ~2.5 MDa mass, ubiquitously found in all eukaryotes. It selectively degrades ubiquitin-conjugated proteins and plays fundamentally indispensable roles in regulating almost all major aspects of cellular activities. To serve as the sole terminal "processor" for myriad ubiquitylation pathways, the proteasome evolved exceptional adaptability in dynamically organizing a large network of proteins, including ubiquitin receptors, shuttle factors, deubiquitinases, AAA-ATPase unfoldases, and ubiquitin ligases, to enable substrate selectivity and processing efficiency and to achieve regulation precision of a vast diversity of substrates. The inner working of the 26S proteasome is among the most sophisticated, enigmatic mechanisms of enzyme machinery in eukaryotic cells. Recent breakthroughs in three-dimensional atomic-level visualization of the 26S proteasome dynamics during polyubiquitylated substrate degradation elucidated an extensively detailed picture of its functional mechanisms, owing to progressive methodological advances associated with cryogenic electron microscopy (cryo-EM). Multiple sites of ubiquitin binding in the proteasome revealed a canonical mode of ubiquitin-dependent substrate engagement. The proteasome conformation in the act of substrate deubiquitylation provided insights into how the deubiquitylating activity of RPN11 is enhanced in the holoenzyme and is coupled to substrate translocation. Intriguingly, three principal modes of coordinated ATP hydrolysis in the heterohexameric AAA-ATPase motor were discovered to regulate intermediate functional steps of the proteasome, including ubiquitin-substrate engagement, deubiquitylation, initiation of substrate translocation and processive substrate degradation. The atomic dissection of the innermost working of the 26S proteasome opens up a new era in our understanding of the ubiquitin-proteasome system and has far-reaching implications in health and disease.
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Affiliation(s)
- Youdong Mao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, 02215, Massachusetts, USA. .,School of Physics, Center for Quantitative Biology, Peking University, Beijing, 100871, China.
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18
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Cascio P. PA28γ: New Insights on an Ancient Proteasome Activator. Biomolecules 2021; 11:228. [PMID: 33562807 PMCID: PMC7915322 DOI: 10.3390/biom11020228] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 02/06/2023] Open
Abstract
PA28 (also known as 11S, REG or PSME) is a family of proteasome regulators whose members are widely present in many of the eukaryotic supergroups. In jawed vertebrates they are represented by three paralogs, PA28α, PA28β, and PA28γ, which assemble as heptameric hetero (PA28αβ) or homo (PA28γ) rings on one or both extremities of the 20S proteasome cylindrical structure. While they share high sequence and structural similarities, the three isoforms significantly differ in terms of their biochemical and biological properties. In fact, PA28α and PA28β seem to have appeared more recently and to have evolved very rapidly to perform new functions that are specifically aimed at optimizing the process of MHC class I antigen presentation. In line with this, PA28αβ favors release of peptide products by proteasomes and is particularly suited to support adaptive immune responses without, however, affecting hydrolysis rates of protein substrates. On the contrary, PA28γ seems to be a slow-evolving gene that is most similar to the common ancestor of the PA28 activators family, and very likely retains its original functions. Notably, PA28γ has a prevalent nuclear localization and is involved in the regulation of several essential cellular processes including cell growth and proliferation, apoptosis, chromatin structure and organization, and response to DNA damage. In striking contrast with the activity of PA28αβ, most of these diverse biological functions of PA28γ seem to depend on its ability to markedly enhance degradation rates of regulatory protein by 20S proteasome. The present review will focus on the molecular mechanisms and biochemical properties of PA28γ, which are likely to account for its various and complex biological functions and highlight the common features with the PA28αβ paralog.
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Affiliation(s)
- Paolo Cascio
- Department of Veterinary Sciences, University of Turin, Largo P. Braccini 2, 10095 Grugliasco, Italy
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19
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Association with proteasome determines pathogenic threshold of polyglutamine expansion diseases. Biochem Biophys Res Commun 2020; 536:95-99. [PMID: 33370719 DOI: 10.1016/j.bbrc.2020.12.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 12/18/2020] [Indexed: 11/21/2022]
Abstract
Expansion of glutamine residue track (polyQ) within soluble protein is responsible for eight autosomal-dominant genetic neurodegenerative disorders. These disorders affect cerebellum, striatum, basal ganglia and other brain regions. Each disease develops when polyQ expansion exceeds a pathogenic threshold (Qth). A pathogenic threshold is unique for each disease but the reasons for variability in Qth within this family of proteins are poorly understood. In the previous publication we proposed that polarity of the regions flanking polyQ track in each protein plays a key role in defining Qth value [1]. To explain the correlation between the polarity of the flanking sequences and Qth we performed quantitative analysis of interactions between polyQ-expanded proteins and proteasome. Based on structural and theoretical modeling, we predict that Qth value is determined by the energy of polar interaction of the flanking regions with the polyQ and proteasome. More polar flanking regions facilitate unfolding of α-helical polyQ conformation adopted inside the proteasome and as a result, increase Qth. Predictions of our model are consistent with Qth values observed in clinic for each of the eight polyQ-expansion disorders. Our results suggest that the agents that can destabilize polyQ α-helical structure may have a beneficial therapeutic effect for treatment of polyQ-expansion disorders.
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20
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Lesne J, Locard-Paulet M, Parra J, Zivković D, Menneteau T, Bousquet MP, Burlet-Schiltz O, Marcoux J. Conformational maps of human 20S proteasomes reveal PA28- and immuno-dependent inter-ring crosstalks. Nat Commun 2020; 11:6140. [PMID: 33262340 PMCID: PMC7708635 DOI: 10.1038/s41467-020-19934-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 11/06/2020] [Indexed: 01/17/2023] Open
Abstract
Hydrogen-Deuterium eXchange coupled to Mass Spectrometry (HDX-MS) is now common practice in structural biology. However, it is most of the time applied to rather small oligomeric complexes. Here, we report on the use of HDX-MS to investigate conformational differences between the human standard 20S (std20S) and immuno 20S (i20s) proteasomes alone or in complex with PA28αβ or PA28γ activators. Their solvent accessibility is analyzed through a dedicated bioinformatic pipeline including stringent statistical analysis and 3D visualization. These data confirm the existence of allosteric differences between the std20S and i20S at the surface of the α-ring triggered from inside the catalytic β-ring. Additionally, binding of the PA28 regulators to the 20S proteasomes modify solvent accessibility due to conformational changes of the β-rings. This work is not only a proof-of-concept that HDX-MS can be used to get structural insights on large multi-protein complexes in solution, it also demonstrates that the binding of the std20S or i20S subtype to any of its PA28 activator triggers allosteric changes that are specific to this 20S/PA28 pair.
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Affiliation(s)
- Jean Lesne
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
- Centre de Biologie Structurale, CNRS, Université de Montpellier, INSERM, 34090, Montpellier, France
| | - Marie Locard-Paulet
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Julien Parra
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Dušan Zivković
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Thomas Menneteau
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, UK
| | - Marie-Pierre Bousquet
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Odile Burlet-Schiltz
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Julien Marcoux
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France.
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21
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The dialogue between the ubiquitin-proteasome system and autophagy: Implications in ageing. Ageing Res Rev 2020; 64:101203. [PMID: 33130248 DOI: 10.1016/j.arr.2020.101203] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/09/2020] [Accepted: 10/25/2020] [Indexed: 02/06/2023]
Abstract
Dysregulated proteostasis is one of the hallmarks of ageing. Damaged proteins may impair cellular function and their accumulation may lead to tissue dysfunction and disease. This is why protective mechanisms to safeguard the cell proteome have evolved. These mechanisms consist of cellular machineries involved in protein quality control, including regulators of protein translation, folding, trafficking and degradation. In eukaryotic cells, protein degradation occurs via two main pathways: the ubiquitin-proteasome system (UPS) and the autophagy-lysosome pathway. Although distinct pathways, they are not isolated systems and have a complementary nature, as evidenced by recent studies. These findings raise the question of how autophagy and the proteasome crosstalk. In this review we address how the two degradation pathways impact each other, thereby adding a new layer of regulation to protein degradation. We also analyze the implications of the UPS and autophagy in ageing.
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22
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The ubiquitin-proteasome system and its crosstalk with mitochondria as therapeutic targets in medicine. Pharmacol Res 2020; 163:105248. [PMID: 33065283 DOI: 10.1016/j.phrs.2020.105248] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022]
Abstract
The ubiquitin-proteasome system constitutes a major pathway for protein degradation in the cell. Therefore the crosstalk of this pathway with mitochondria is a major topic with direct relevance to many mitochondrial diseases. Proteasome dysfunction triggers not only protein toxicity, but also mitochondrial dysfunction. The involvement of proteasomes in the regulation of protein transport into mitochondria contributes to an increase in mitochondrial function defects. On the other hand, mitochondrial impairment stimulates reactive oxygen species production, which increases protein damage, and protein misfolding and aggregation leading to proteasome overload. Concurrently, mitochondrial dysfunction compromises cellular ATP production leading to reduced protein ubiquitination and proteasome activity. In this review we discuss the complex relationship and interdependence of the ubiquitin-proteasome system and mitochondria. Furthermore, we describe pharmacological inhibition of proteasome activity as a novel strategy to treat a group of mitochondrial diseases.
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23
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Allosteric coupling between α-rings of the 20S proteasome. Nat Commun 2020; 11:4580. [PMID: 32917864 PMCID: PMC7486400 DOI: 10.1038/s41467-020-18415-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 08/21/2020] [Indexed: 11/21/2022] Open
Abstract
Proteasomal machinery performs essential regulated protein degradation in eukaryotes. Classic proteasomes are symmetric, with a regulatory ATPase docked at each end of the cylindrical 20S. Asymmetric complexes are also present in cells, either with a single ATPase or with an ATPase and non-ATPase at two opposite ends. The mechanism that populates these different proteasomal complexes is unknown. Using archaea homologs, we construct asymmetric forms of proteasomes. We demonstrate that the gate conformation of the two opposite ends of 20S are coupled: binding one ATPase opens a gate locally, and also opens the opposite gate allosterically. Such allosteric coupling leads to cooperative binding of proteasomal ATPases to 20S and promotes formation of proteasomes symmetrically configured with two identical ATPases. It may also promote formation of asymmetric complexes with an ATPase and a non-ATPase at opposite ends. We propose that in eukaryotes a similar mechanism regulates the composition of the proteasomal population. The 26S proteasome is a protein degradation machine composed of a 20S core particle (CP) flanked at one or both ends by a 19S ATPase regulatory particle (RP). Here the authors reconstitute asymmetric archaeal proteasomes and reveal allosteric coupling between the conformations of gates in the α-rings positioned at opposite ends of the CP, which modulates RP assembly and substrate entry.
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24
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Tundo GR, Sbardella D, Santoro AM, Coletta A, Oddone F, Grasso G, Milardi D, Lacal PM, Marini S, Purrello R, Graziani G, Coletta M. The proteasome as a druggable target with multiple therapeutic potentialities: Cutting and non-cutting edges. Pharmacol Ther 2020; 213:107579. [PMID: 32442437 PMCID: PMC7236745 DOI: 10.1016/j.pharmthera.2020.107579] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 01/10/2023]
Abstract
Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.
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Affiliation(s)
- G R Tundo
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
| | | | - A M Santoro
- CNR, Institute of Crystallography, Catania, Italy
| | - A Coletta
- Department of Chemistry, University of Aarhus, Aarhus, Denmark
| | - F Oddone
- IRCCS-Fondazione Bietti, Rome, Italy
| | - G Grasso
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - D Milardi
- CNR, Institute of Crystallography, Catania, Italy
| | - P M Lacal
- Laboratory of Molecular Oncology, IDI-IRCCS, Rome, Italy
| | - S Marini
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - R Purrello
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - G Graziani
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
| | - M Coletta
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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25
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Boulpicante M, Darrigrand R, Pierson A, Salgues V, Rouillon M, Gaudineau B, Khaled M, Cattaneo A, Bachi A, Cascio P, Apcher S. Tumors escape immunosurveillance by overexpressing the proteasome activator PSME3. Oncoimmunology 2020; 9:1761205. [PMID: 32923122 PMCID: PMC7458623 DOI: 10.1080/2162402x.2020.1761205] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 04/03/2020] [Indexed: 11/09/2022] Open
Abstract
The success of CD8+ T cell-based cancer immunotherapy emphasizes the importance of understanding the mechanisms of generation of MHC-I peptide ligands and the possible pathways of tumor cell escape from immunosurveillance. Recently, we showed that peptides generated in the nucleus during a pioneer round of mRNA translation (pioneer translation products, or PTPs) are an important source of tumor specific peptides which correlates with the aberrant splicing and transcription events associated with oncogenesis. Here we show that up-regulation of PSME3 proteasome activator in cancer cells results in increased destruction of PTP-derived peptides in the nucleus thus enabling cancer cell to subvert immunosurveillance. These findings unveil a previously unexpected role for PSME3 in antigen processing and identify PSME3 as a druggable target to improve the efficacy of cancer immunotherapy.
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Affiliation(s)
- Mathilde Boulpicante
- Immunologie des Tumeurs et Immunothérapie, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Romain Darrigrand
- Immunologie des Tumeurs et Immunothérapie, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Alison Pierson
- Immunologie des Tumeurs et Immunothérapie, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Valérie Salgues
- Immunologie des Tumeurs et Immunothérapie, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Marine Rouillon
- Immunologie des Tumeurs et Immunothérapie, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Benoit Gaudineau
- Dynamique des Cellules Tumorales, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Mehdi Khaled
- Dynamique des Cellules Tumorales, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
| | - Angela Cattaneo
- IFOM, The FIRC Institute of Molecular Oncology, Milano, Italy
| | - Angela Bachi
- IFOM, The FIRC Institute of Molecular Oncology, Milano, Italy
| | - Paolo Cascio
- Department of Veterinary Sciences, University of Turin, 10095, Grugliasco, Turin, Italy
| | - Sébastien Apcher
- Immunologie des Tumeurs et Immunothérapie, Université Paris-Saclay, Institut Gustave Roussy, Inserm, Villejuif, France
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26
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Wang X, Meul T, Meiners S. Exploring the proteasome system: A novel concept of proteasome inhibition and regulation. Pharmacol Ther 2020; 211:107526. [PMID: 32173559 DOI: 10.1016/j.pharmthera.2020.107526] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/08/2020] [Indexed: 12/13/2022]
Abstract
The proteasome is a well-identified therapeutic target for cancer treatment. It acts as the main protein degradation system in the cell and degrades key mediators of cell growth, survival and function. The term "proteasome" embraces a whole family of distinct complexes, which share a common proteolytic core, the 20S proteasome, but differ by their attached proteasome activators. Each of these proteasome complexes plays specific roles in the control of cellular function. In addition, distinct proteasome interacting proteins regulate proteasome activity in subcellular compartments and in response to cellular signals. Proteasome activators and regulators may thus serve as building blocks to fine-tune proteasome function in the cell according to cellular needs. Inhibitors of the proteasome, e.g. the FDA approved drugs Velcade™, Kyprolis™, Ninlaro™, inactivate the catalytic 20S core and effectively block protein degradation of all proteasome complexes in the cell resulting in inhibition of cell growth and induction of apoptosis. Efficacy of these inhibitors, however, is hampered by their pronounced cytotoxic side-effects as well as by the emerging development of resistance to catalytic proteasome inhibitors. Targeted inhibition of distinct buiding blocks of the proteasome system, i.e. proteasome activators or regulators, represents an alternative strategy to overcome these limitations. In this review, we stress the importance of the diversity of the proteasome complexes constituting an entire proteasome system. Our building block concept provides a rationale for the defined targeting of distinct proteasome super-complexes in disease. We thereby aim to stimulate the development of innovative therapeutic approaches beyond broad catalytic proteasome inhibition.
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Affiliation(s)
- Xinyuan Wang
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Thomas Meul
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Silke Meiners
- Comprehensive Pneumology Center (CPC), University Hospital of the Ludwig-Maximilians-University (LMU) and Helmholtz Zentrum München, German Center for Lung Research (DZL), 81377 Munich, Germany.
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27
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Exploring long-range cooperativity in the 20S proteasome core particle from Thermoplasma acidophilum using methyl-TROSY-based NMR. Proc Natl Acad Sci U S A 2020; 117:5298-5309. [PMID: 32094174 DOI: 10.1073/pnas.1920770117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The 20S core particle (CP) proteasome is a molecular assembly catalyzing the degradation of misfolded proteins or proteins no longer required for function. It is composed of four stacked heptameric rings that form a barrel-like structure, sequestering proteolytic sites inside its lumen. Proteasome function is regulated by gates derived from the termini of α-rings and through binding of regulatory particles (RPs) to one or both ends of the barrel. The CP is dynamic, with an extensive allosteric pathway extending from one end of the molecule to catalytic sites in its center. Here, using methyl-transverse relaxation optimized spectroscopy (TROSY)-based NMR optimized for studies of high-molecular-weight complexes, we evaluate whether the pathway extends over the entire 150-Å length of the molecule. By exploiting a number of different labeling schemes, the two halves of the molecule can be distinguished, so that the effects of 11S RP binding, or the introduction of gate or allosteric pathway mutations at one end of the barrel can be evaluated at the distal end. Our results establish that while 11S binding and the introduction of key mutations affect each half of the CP allosterically, they do not further couple opposite ends of the molecule. This may have implications for the function of so-called "hybrid" proteasomes where each end of the CP is bound with a different regulator, allowing the CP to be responsive to both RPs simultaneously. The methodology presented introduces a general NMR strategy for dissecting pathways of communication in homo-oligomeric molecular machines.
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28
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Proteasome Inhibitors: Harnessing Proteostasis to Combat Disease. Molecules 2020; 25:molecules25030671. [PMID: 32033280 PMCID: PMC7037493 DOI: 10.3390/molecules25030671] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/25/2020] [Accepted: 01/28/2020] [Indexed: 02/07/2023] Open
Abstract
The proteasome is the central component of the main cellular protein degradation pathway. During the past four decades, the critical function of the proteasome in numerous physiological processes has been revealed, and proteasome activity has been linked to various human diseases. The proteasome prevents the accumulation of misfolded proteins, controls the cell cycle, and regulates the immune response, to name a few important roles for this macromolecular "machine." As a therapeutic target, proteasome inhibitors have been approved for the treatment of multiple myeloma and mantle cell lymphoma. However, inability to sufficiently inhibit proteasome activity at tolerated doses has hampered efforts to expand the scope of proteasome inhibitor-based therapies. With emerging new modalities in myeloma, it might seem challenging to develop additional proteasome-based therapies. However, the constant development of new applications for proteasome inhibitors and deeper insights into the intricacies of protein homeostasis suggest that proteasome inhibitors might have novel therapeutic applications. Herein, we summarize the latest advances in proteasome inhibitor development and discuss the future of proteasome inhibitors and other proteasome-based therapies in combating human diseases.
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Kwon D, Kim SM, Correia MA. Cytochrome P450 endoplasmic reticulum-associated degradation (ERAD): therapeutic and pathophysiological implications. Acta Pharm Sin B 2020; 10:42-60. [PMID: 31993306 PMCID: PMC6976991 DOI: 10.1016/j.apsb.2019.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 02/07/2023] Open
Abstract
The hepatic endoplasmic reticulum (ER)-anchored cytochromes P450 (P450s) are mixed-function oxidases engaged in the biotransformation of physiologically relevant endobiotics as well as of myriad xenobiotics of therapeutic and environmental relevance. P450 ER-content and hence function is regulated by their coordinated hemoprotein syntheses and proteolytic turnover. Such P450 proteolytic turnover occurs through a process known as ER-associated degradation (ERAD) that involves ubiquitin-dependent proteasomal degradation (UPD) and/or autophagic-lysosomal degradation (ALD). Herein, on the basis of available literature reports and our own recent findings of in vitro as well as in vivo experimental studies, we discuss the therapeutic and pathophysiological implications of altered P450 ERAD and its plausible clinical relevance. We specifically (i) describe the P450 ERAD-machinery and how it may be repurposed for the generation of antigenic P450 peptides involved in P450 autoantibody pathogenesis in drug-induced acute hypersensitivity reactions and liver injury, or viral hepatitis; (ii) discuss the relevance of accelerated or disrupted P450-ERAD to the pharmacological and/or toxicological effects of clinically relevant P450 drug substrates; and (iii) detail the pathophysiological consequences of disrupted P450 ERAD, contributing to non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) under certain synergistic cellular conditions.
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Key Words
- 3MA, 3-methyladenine
- AAA, ATPases associated with various cellular activities
- ACC1, acetyl-CoA carboxylase 1
- ACC2, acetyl-CoA carboxylase 2
- ACHE, acetylcholinesterase
- ACOX1, acyl-CoA oxidase 1
- ALD, autophagic-lysosomal degradation
- AMPK1
- AP-1, activator protein 1
- ASK1, apoptosis signal-regulating kinase
- ATF2, activating transcription factor 2
- AdipoR1, gene of adiponectin receptor 1
- Atg14, autophagy-related 14
- CBZ, carbamazepine
- CHIP E3 ubiquitin ligase
- CHIP, carboxy-terminus of Hsc70-interacting protein
- Cytochromes P450
- Endoplasmic reticulum-associated degradation
- FOXO, forkhead box O
- Fas, fatty acid synthase
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- INH, isoniazid
- IRS1, insulin receptor substrate 1
- Il-1β, interleukin 1 β
- Il-6, interleukin 6
- Insig1, insulin-induced gene 1
- JNK1
- Lpl, lipoprotein lipase
- Mcp1, chemokine (C–C motif) ligand 1
- Non-alcoholic fatty liver disease
- Non-alcoholic steatohepatitis
- Pgc1, peroxisome proliferator-activated receptor coactivator 1
- SREBP1c, sterol regulatory element binding transcription factor 1c
- Scd1, stearoyl-coenzyme A desaturase
- Tnf, tumor necrosis factor
- UPD, ubiquitin (Ub)-dependent proteasomal degradation
- Ub, ubiquitin
- gp78/AMFR E3 ubiquitin ligase
- gp78/AMFR, autocrine motility factor receptor
- shRNAi, shRNA interference
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Coux O, Zieba BA, Meiners S. The Proteasome System in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:55-100. [DOI: 10.1007/978-3-030-38266-7_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Toste Rêgo A, da Fonseca PCA. Characterization of Fully Recombinant Human 20S and 20S-PA200 Proteasome Complexes. Mol Cell 2019; 76:138-147.e5. [PMID: 31473102 PMCID: PMC6863390 DOI: 10.1016/j.molcel.2019.07.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/27/2019] [Accepted: 07/10/2019] [Indexed: 12/31/2022]
Abstract
Proteasomes are essential in all eukaryotic cells. However, their function and regulation remain considerably elusive, particularly those of less abundant variants. We demonstrate the human 20S proteasome recombinant assembly and confirmed the recombinant complex integrity biochemically and with a 2.6 Å resolution cryo-EM map. To assess its competence to form higher-order assemblies, we prepared and analyzed recombinant human 20S-PA200, a poorly characterized nuclear complex. Its 3.0 Å resolution cryo-EM structure reveals the PA200 unique architecture; the details of its intricate interactions with the proteasome, resulting in unparalleled proteasome α ring rearrangements; and the molecular basis for PA200 allosteric modulation of the proteasome active sites. Non-protein cryo-EM densities could be assigned to PA200-bound inositol phosphates, and we speculate regarding their functional role. Here we open extensive opportunities to study the fundamental properties of the diverse and distinct eukaryotic proteasome variants and to improve proteasome targeting under different therapeutic conditions. Recombinant human 20S proteasomes and 20S-PA200 complexes are characterized Cryo-EM reveals intricate 20S-PA200 interactions and PA200-bound cofactors PA200 binding is allosterically communicated to the proteolytic active sites Basis to fully characterize the function and regulation of proteasome variants
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Affiliation(s)
- Ana Toste Rêgo
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Paula C A da Fonseca
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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Morozov AV, Karpov VL. Proteasomes and Several Aspects of Their Heterogeneity Relevant to Cancer. Front Oncol 2019; 9:761. [PMID: 31456945 PMCID: PMC6700291 DOI: 10.3389/fonc.2019.00761] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/29/2019] [Indexed: 01/19/2023] Open
Abstract
The life of every organism is dependent on the fine-tuned mechanisms of protein synthesis and breakdown. The degradation of most intracellular proteins is performed by the ubiquitin proteasome system (UPS). Proteasomes are central elements of the UPS and represent large multisubunit protein complexes directly responsible for the protein degradation. Accumulating data indicate that there is an intriguing diversity of cellular proteasomes. Different proteasome forms, containing different subunits and attached regulators have been described. In addition, proteasomes specific for a particular tissue were identified. Cancer cells are highly dependent on the proper functioning of the UPS in general, and proteasomes in particular. At the same time, the information regarding the role of different proteasome forms in cancer is limited. This review describes the functional and structural heterogeneity of proteasomes, their association with cancer as well as several established and novel proteasome-directed therapeutic strategies.
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Affiliation(s)
- Alexey V. Morozov
- Laboratory of Regulation of Intracellular Proteolysis, W.A. Engelhardt Institute of Molecular Biology RAS, Moscow, Russia
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Xie SC, Metcalfe RD, Hanssen E, Yang T, Gillett DL, Leis AP, Morton CJ, Kuiper MJ, Parker MW, Spillman NJ, Wong W, Tsu C, Dick LR, Griffin MDW, Tilley L. The structure of the PA28-20S proteasome complex from Plasmodium falciparum and implications for proteostasis. Nat Microbiol 2019; 4:1990-2000. [PMID: 31384003 DOI: 10.1038/s41564-019-0524-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 06/25/2019] [Indexed: 11/09/2022]
Abstract
The activity of the proteasome 20S catalytic core is regulated by protein complexes that bind to one or both ends. The PA28 regulator stimulates 20S proteasome peptidase activity in vitro, but its role in vivo remains unclear. Here, we show that genetic deletion of the PA28 regulator from Plasmodium falciparum (Pf) renders malaria parasites more sensitive to the antimalarial drug dihydroartemisinin, indicating that PA28 may play a role in protection against proteotoxic stress. The crystal structure of PfPA28 reveals a bell-shaped molecule with an inner pore that has a strong segregation of charges. Small-angle X-ray scattering shows that disordered loops, which are not resolved in the crystal structure, extend from the PfPA28 heptamer and surround the pore. Using single particle cryo-electron microscopy, we solved the structure of Pf20S in complex with one and two regulatory PfPA28 caps at resolutions of 3.9 and 3.8 Å, respectively. PfPA28 binds Pf20S asymmetrically, strongly engaging subunits on only one side of the core. PfPA28 undergoes rigid body motions relative to Pf20S. Molecular dynamics simulations support conformational flexibility and a leaky interface. We propose lateral transfer of short peptides through the dynamic interface as a mechanism facilitating the release of proteasome degradation products.
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Affiliation(s)
- Stanley C Xie
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Riley D Metcalfe
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Eric Hanssen
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.,Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Tuo Yang
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - David L Gillett
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Andrew P Leis
- Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Craig J Morton
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Michael W Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.,Australian Cancer Research Foundation Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Natalie J Spillman
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Wilson Wong
- Infection and Immunity Division, The Walter and Eliza Hall Institute, Parkville, Victoria, Australia
| | - Christopher Tsu
- Oncology Clinical R&D, Takeda Pharmaceuticals International Co., Cambridge, MA, USA
| | - Lawrence R Dick
- Oncology Clinical R&D, Takeda Pharmaceuticals International Co., Cambridge, MA, USA
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.
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Kors S, Geijtenbeek K, Reits E, Schipper-Krom S. Regulation of Proteasome Activity by (Post-)transcriptional Mechanisms. Front Mol Biosci 2019; 6:48. [PMID: 31380390 PMCID: PMC6646590 DOI: 10.3389/fmolb.2019.00048] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/11/2019] [Indexed: 12/23/2022] Open
Abstract
Intracellular protein synthesis, folding, and degradation are tightly controlled processes to ensure proper protein homeostasis. The proteasome is responsible for the degradation of the majority of intracellular proteins, which are often targeted for degradation via polyubiquitination. However, the degradation rate of proteins is also affected by the capacity of proteasomes to recognize and degrade these substrate proteins. This capacity is regulated by a variety of proteasome modulations including (1) changes in complex composition, (2) post-translational modifications, and (3) altered transcription of proteasomal subunits and activators. Various diseases are linked to proteasome modulation and altered proteasome function. A better understanding of these modulations may offer new perspectives for therapeutic intervention. Here we present an overview of these three proteasome modulating mechanisms to give better insight into the diversity of proteasomes.
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Affiliation(s)
- Suzan Kors
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Karlijne Geijtenbeek
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Eric Reits
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Sabine Schipper-Krom
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Cellular Responses to Proteasome Inhibition: Molecular Mechanisms and Beyond. Int J Mol Sci 2019; 20:ijms20143379. [PMID: 31295808 PMCID: PMC6678303 DOI: 10.3390/ijms20143379] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/26/2019] [Accepted: 07/01/2019] [Indexed: 02/06/2023] Open
Abstract
Proteasome inhibitors have been actively tested as potential anticancer drugs and in the treatment of inflammatory and autoimmune diseases. Unfortunately, cells adapt to survive in the presence of proteasome inhibitors activating a variety of cell responses that explain why these therapies have not fulfilled their expected results. In addition, all proteasome inhibitors tested and approved by the FDA have caused a variety of side effects in humans. Here, we describe the different types of proteasome complexes found within cells and the variety of regulators proteins that can modulate their activities, including those that are upregulated in the context of inflammatory processes. We also summarize the adaptive cellular responses activated during proteasome inhibition with special emphasis on the activation of the Autophagic-Lysosomal Pathway (ALP), proteaphagy, p62/SQSTM1 enriched-inclusion bodies, and proteasome biogenesis dependent on Nrf1 and Nrf2 transcription factors. Moreover, we discuss the role of IRE1 and PERK sensors in ALP activation during ER stress and the involvement of two deubiquitinases, Rpn11 and USP14, in these processes. Finally, we discuss the aspects that should be currently considered in the development of novel strategies that use proteasome activity as a therapeutic target for the treatment of human diseases.
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Kudriaeva AA, Belogurov AA. Proteasome: a Nanomachinery of Creative Destruction. BIOCHEMISTRY (MOSCOW) 2019; 84:S159-S192. [PMID: 31213201 DOI: 10.1134/s0006297919140104] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In the middle of the 20th century, it was postulated that degradation of intracellular proteins is a stochastic process. More than fifty years of intense studies have finally proven that protein degradation is a very complex and tightly regulated in time and space process that plays an incredibly important role in the vast majority of metabolic pathways. Degradation of more than a half of intracellular proteins is controlled by a hierarchically aligned and evolutionarily perfect system consisting of many components, the main ones being ubiquitin ligases and proteasomes, together referred to as the ubiquitin-proteasome system (UPS). The UPS includes more than 1000 individual components, and most of them are critical for the cell functioning and survival. In addition to the well-known signaling functions of ubiquitination, such as modification of substrates for proteasomal degradation and DNA repair, polyubiquitin (polyUb) chains are involved in other important cellular processes, e.g., cell cycle regulation, immunity, protein degradation in mitochondria, and even mRNA stability. This incredible variety of ubiquitination functions is related to the ubiquitin ability to form branching chains through the ε-amino group of any of seven lysine residues in its sequence. Deubiquitination is accomplished by proteins of the deubiquitinating enzyme family. The second main component of the UPS is proteasome, a multisubunit proteinase complex that, in addition to the degradation of functionally exhausted and damaged proteins, regulates many important cellular processes through controlled degradation of substrates, for example, transcription factors and cyclins. In addition to the ubiquitin-dependent-mediated degradation, there is also ubiquitin-independent degradation, when the proteolytic signal is either an intrinsic protein sequence or shuttle molecule. Protein hydrolysis is a critically important cellular function; therefore, any abnormalities in this process lead to systemic impairments further transforming into serious diseases, such as diabetes, malignant transformation, and neurodegenerative disorders (multiple sclerosis, Alzheimer's disease, Parkinson's disease, Creutzfeldt-Jakob disease and Huntington's disease). In this review, we discuss the mechanisms that orchestrate all components of the UPS, as well as the plurality of the fine-tuning pathways of proteasomal degradation.
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Affiliation(s)
- A A Kudriaeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - A A Belogurov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia. .,Lomonosov Moscow State University, Moscow, 119991, Russia
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Buneeva OA, Medvedev AE. [Ubiquitin-independent protein degradation in proteasomes]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2019; 64:134-148. [PMID: 29723144 DOI: 10.18097/pbmc20186402134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Proteasomes are large supramolecular protein complexes present in all prokaryotic and eukaryotic cells, where they perform targeted degradation of intracellular proteins. Until recently, it was generally accepted that prior proteolytic degradation in proteasomes the proteins had to be targeted by ubiquitination: the ATP-dependent addition of (typically four sequential) residues of the low-molecular ubiquitin protein, involving the ubiquitin-activating enzyme, ubiquitin-conjugating enzyme and ubiquitin ligase. The cytoplasm and nucleoplasm proteins labeled in this way are then digested in 26S proteasomes. However, in recent years it has become increasingly clear that using this route the cell eliminates only a part of unwanted proteins. Many proteins can be cleaved by the 20S proteasome in an ATP-independent manner and without previous ubiquitination. Ubiquitin-independent protein degradation in proteasomes is a relatively new area of studies of the role of the ubiquitin-proteasome system. However, recent data obtained in this direction already correct existing concepts about proteasomal degradation of proteins and its regulation. Ubiquitin-independent proteasome degradation needs the main structural precondition in proteins: the presence of unstructured regions in the amino acid sequences that provide interaction with the proteasome. Taking into consideration that in humans almost half of all genes encode proteins that contain a certain proportion of intrinsically disordered regions, it appears that the list of proteins undergoing ubiquitin-independent degradation will demonstrate further increase. Since 26S of proteasomes account for only 30% of the total proteasome content in mammalian cells, most of the proteasomes exist in the form of 20S complexes. The latter suggests that ubiquitin-independent proteolysis performed by the 20S proteasome is a natural process of removing damaged proteins from the cell and maintaining a constant level of intrinsically disordered proteins. In this case, the functional overload of proteasomes in aging and/or other types of pathological processes, if it is not accompanied by triggering more radical mechanisms for the elimination of damaged proteins, organelles and whole cells, has the most serious consequences for the whole organism.
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Affiliation(s)
- O A Buneeva
- Institute of Biomedical Chemistry, Moscow, Russia
| | - A E Medvedev
- Institute of Biomedical Chemistry, Moscow, Russia
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Caputi FF, Rullo L, Stamatakos S, Candeletti S, Romualdi P. Interplay between the Endogenous Opioid System and Proteasome Complex: Beyond Signaling. Int J Mol Sci 2019; 20:ijms20061441. [PMID: 30901925 PMCID: PMC6470665 DOI: 10.3390/ijms20061441] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/13/2019] [Accepted: 03/19/2019] [Indexed: 02/07/2023] Open
Abstract
Intracellular signaling mechanisms underlying the opioid system regulation of nociception, neurotransmitters release, stress responses, depression, and the modulation of reward circuitry have been investigated from different points of view. The presence of the ubiquitin proteasome system (UPS) in the synaptic terminations suggest a potential role of ubiquitin-dependent mechanisms in the control of the membrane occupancy by G protein-coupled receptors (GPCRs), including those belonging to the opioid family. In this review, we focused our attention on the role played by the ubiquitination processes and by UPS in the modulation of opioid receptor signaling and in pathological conditions involving the endogenous opioid system. The collective evidence here reported highlights the potential usefulness of proteasome inhibitors in neuropathic pain, addictive behavior, and analgesia since these molecules can reduce pain behavioral signs, heroin self-administration, and the development of morphine analgesic tolerance. Moreover, the complex mechanisms involved in the effects induced by opioid agonists binding to their receptors include the ubiquitination process as a post-translational modification which plays a relevant role in receptor trafficking and degradation. Hence, UPS modulation may offer novel opportunities to control the balance between therapeutic versus adverse effects evoked by opioid receptor activation, thus, representing a promising druggable target.
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Affiliation(s)
- Francesca Felicia Caputi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Laura Rullo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Serena Stamatakos
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Sanzio Candeletti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
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Zheng Y, Shimamoto S, Maruno T, Kobayashi Y, Matsuura Y, Kawahara K, Yoshida T, Ohkubo T. N-terminal HCV core protein fragment decreases 20S proteasome activity in the presence of PA28γ. Biochem Biophys Res Commun 2018; 509:590-595. [PMID: 30602418 DOI: 10.1016/j.bbrc.2018.12.167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 12/26/2018] [Indexed: 12/18/2022]
Abstract
The Hepatitis C virus (HCV) core protein plays a crucial role in the development of chronic liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). Its involvement in these diseases is reportedly abolished by a knockout of the proteasome activator PA28γ gene in transgenic mice, suggesting an interaction between the core protein and the PA28γ-proteasome system. This study found a direct interaction between the N-terminal 1-71 fragment of HCV core protein (Core71) and PA28γ in vitro, and that this interaction was found to enhance PA28γ-20S proteasome complex formation. While 20S proteasome activity was increased by PA28γ, it was significantly reduced by Core71 attachment in a dose-dependent manner. These results suggest that the Core-PA28γ interaction has an important role in regulating 20S proteasome activity and furthers our understanding of the pathogenesis of HCV.
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Affiliation(s)
- Yang Zheng
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shigeru Shimamoto
- Faculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka, 577-8502, Japan
| | - Takahiro Maruno
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yuji Kobayashi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshiharu Matsuura
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kazuki Kawahara
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takuya Yoshida
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tadayasu Ohkubo
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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Buneeva OA, Medvedev AE. Ubiquitin-Independent Degradation of Proteins in Proteasomes. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES B: BIOMEDICAL CHEMISTRY 2018. [DOI: 10.1134/s1990750818030022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ogorevc E, Schiffrer ES, Sosič I, Gobec S. A patent review of immunoproteasome inhibitors. Expert Opin Ther Pat 2018; 28:517-540. [PMID: 29865878 DOI: 10.1080/13543776.2018.1484904] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION The ubiquitin-proteasome system is responsible for maintaining protein homeostasis and regulating a variety of cellular processes. The constitutive proteasome is expressed in all cells while the immunoproteasome (IP) is predominantly found in cells of hematopoietic origin. In other cells, the expression of IP can be induced under the influence of cytokines released by T cells during acute immune and stress responses. Inhibitors of IP are of significant interest, because it is expected that selective inhibition of the IP would cause fewer adverse effects. AREAS COVERED There is a considerable interest on patenting IP-specific inhibitors. Relevant patents and patent applications disclosing IP inhibitors are summarized and divided into two parts according to the chemical characteristics of compounds. We also briefly report on the biochemical methods used in the patents to profile the characteristics of IP inhibitors. EXPERT OPINION Several selective inhibitors of IP with a promising ability to address autoimmune and inflammatory diseases are being developed. Peptidic compounds are prevalent and the most advanced IP-selective compounds to date, ONX-0914 and KZR-616, are tripeptide epoxyketone-based molecules. However, some patents disclose that IP-selective inhibition is possible with compounds possessing non-peptidic scaffolds indicating countless possibilities to address inhibition of IP in the future.
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Affiliation(s)
- Eva Ogorevc
- a Faculty of Pharmacy , University of Ljubljana , Ljubljana , Slovenia
| | | | - Izidor Sosič
- a Faculty of Pharmacy , University of Ljubljana , Ljubljana , Slovenia
| | - Stanislav Gobec
- a Faculty of Pharmacy , University of Ljubljana , Ljubljana , Slovenia
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Increased proteasomal activity supports photoreceptor survival in inherited retinal degeneration. Nat Commun 2018; 9:1738. [PMID: 29712894 PMCID: PMC5928105 DOI: 10.1038/s41467-018-04117-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 04/04/2018] [Indexed: 12/14/2022] Open
Abstract
Inherited retinal degenerations, affecting more than 2 million people worldwide, are caused by mutations in over 200 genes. This suggests that the most efficient therapeutic strategies would be mutation independent, i.e., targeting common pathological conditions arising from many disease-causing mutations. Previous studies revealed that one such condition is an insufficiency of the ubiquitin–proteasome system to process misfolded or mistargeted proteins in affected photoreceptor cells. We now report that retinal degeneration in mice can be significantly delayed by increasing photoreceptor proteasomal activity. The largest effect is observed upon overexpression of the 11S proteasome cap subunit, PA28α, which enhanced ubiquitin-independent protein degradation in photoreceptors. Applying this strategy to mice bearing one copy of the P23H rhodopsin mutant, a mutation frequently encountered in human patients, quadruples the number of surviving photoreceptors in the inferior retina of 6-month-old mice. This striking therapeutic effect demonstrates that proteasomes are an attractive target for fighting inherited blindness. Proteasomal overload can be found in a broad spectrum of mouse models of retinal degeneration. Here the authors find that overexpressing the PA28α subunit of the 11S proteasome cap increased the number of surviving functional photoreceptor cells in a mouse model of retinal degeneration bearing the P23H mutation in rhodopsin.
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The 20S immunoproteasome and constitutive proteasome bind with the same affinity to PA28αβ and equally degrade FAT10. Mol Immunol 2017; 113:22-30. [PMID: 29208314 DOI: 10.1016/j.molimm.2017.11.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 11/22/2022]
Abstract
The 20S immunoproteasome (IP) is an interferon(IFN)-γ - and tumor necrosis factor (TNF) -inducible variant of the 20S constitutive proteasome (CP) in which all its peptidolytically active subunits β1, β2, and β5 are replaced by their cytokine inducible homologues β1i (LMP2), β2i (MECL-1), and β5i (LMP7). These subunit replacements alter the cleavage specificity of the proteasome and the spectrum of proteasome-generated peptide ligands of MHC class I molecules. In addition to antigen processing, the IP has recently been shown to serve unique functions in the generation of pro-inflammatory T helper cell subtypes and cytokines as well as in the pathogenesis of autoimmune diseases, but the mechanistic involvement of the IP in these processes has remained elusive. In this study we investigated whether the IP differs from the CP in the interaction with two IFN-γ/TNF inducible factors: the 11S proteasome regulator PA28αβ and the ubiquitin-like modifier FAT10 (ubiquitin D). Using thermophoresis, we determined the affinity of PA28αβ for the CP and IP to be 12.2nM +/- 2.8nM and 15.3nM +/- 2.7nM, respectively, which is virtually identical. Also the activation of the peptidolytic activities of the IP and CP by PA28αβ did not differ. For FAT10 we determined the degradation kinetics in cycloheximide chase experiments in cells expressing almost exclusively IP or CP as well as in IFN-γ stimulated and unstimulated cells and found no differences between the degradation rates. Taken together, we conclude that neither differences in the binding strength to, nor activation by PA28αβ, nor a difference in the rate of FAT10-mediated degradation can account for distinct functional capabilities of the IP as compared to the CP.
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Eskandari SK, Seelen MAJ, Lin G, Azzi JR. The immunoproteasome: An old player with a novel and emerging role in alloimmunity. Am J Transplant 2017; 17:3033-3039. [PMID: 28719024 DOI: 10.1111/ajt.14435] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 06/20/2017] [Accepted: 07/06/2017] [Indexed: 01/25/2023]
Abstract
Modern treatment strategies for the maintenance of allograft acceptance frequently target ubiquitously-expressed pathways, leading to significant side-effects and poor long-term allograft outcomes. Constitutive proteasome inhibitors, which have recently been introduced for the treatment of antibody-mediated rejection, target the ubiquitously-expressed proteasome. To limit off-target effects and serious mechanism-based toxicity, however, these inhibitors are administered intermittently and suboptimally. Immunoproteasomes, which are an inducible subset of proteasomes enriched in immune cells, replace constitutive proteasomes after cell exposure to proinflammatory cytokines such as interferon-γ. While immunoproteasomes were first described as processors of antigen for presentation by major histocompatibility complex molecules, recent findings point to its broader biological roles. These vary from activating different subsets of the immune system, by controlling transcriptional activators and downstream cytokines, to affecting their differentiation and survival. These emerging roles of the immunoproteasome in activated immune cells have made it a rational candidate for the targeted treatment of immune-mediated diseases. Preclinical studies have established its role in maintaining allograft acceptance without significant short- or long-term toxicity. This review provides a brief background of the immunoproteasome and outlines its role in immunological pathways and its potential in alloimmunity.
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Affiliation(s)
- S K Eskandari
- Transplantation Research Center, Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M A J Seelen
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - G Lin
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - J R Azzi
- Transplantation Research Center, Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Gu Y, Xu K, Torre C, Samur M, Barwick BG, Rupji M, Arora J, Neri P, Kaufman J, Nooka A, Bernal-Mizrachi L, Vertino P, Sun SY, Chen J, Munshi N, Fu H, Kowalski J, Boise LH, Lonial S. 14-3-3ζ binds the proteasome, limits proteolytic function and enhances sensitivity to proteasome inhibitors. Leukemia 2017; 32:744-751. [DOI: 10.1038/leu.2017.288] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 07/06/2017] [Accepted: 08/23/2017] [Indexed: 01/02/2023]
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Korovila I, Hugo M, Castro JP, Weber D, Höhn A, Grune T, Jung T. Proteostasis, oxidative stress and aging. Redox Biol 2017; 13:550-567. [PMID: 28763764 PMCID: PMC5536880 DOI: 10.1016/j.redox.2017.07.008] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 07/04/2017] [Accepted: 07/09/2017] [Indexed: 12/21/2022] Open
Abstract
The production of reactive species is an inevitable by-product of metabolism and thus, life itself. Since reactive species are able to damage cellular structures, especially proteins, as the most abundant macromolecule of mammalian cells, systems are necessary which regulate and preserve a functional cellular protein pool, in a process termed “proteostasis”. Not only the mammalian protein pool is subject of a constant turnover, organelles are also degraded and rebuild. The most important systems for these removal processes are the “ubiquitin-proteasomal system” (UPS), the central proteolytic machinery of mammalian cells, mainly responsible for proteostasis, as well as the “autophagy-lysosomal system”, which mediates the turnover of organelles and large aggregates. Many age-related pathologies and the aging process itself are accompanied by a dysregulation of UPS, autophagy and the cross-talk between both systems. This review will describe the sources and effects of oxidative stress, preservation of cellular protein- and organelle-homeostasis and the effects of aging on proteostasis in mammalian cells.
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Affiliation(s)
- Ioanna Korovila
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany
| | - Martín Hugo
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany
| | - José Pedro Castro
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany; Faculty of Medicine, Department of Biomedicine, University of Porto, 4200-319, Portugal; Institute for Innovation and Health Research (I3S), Aging and Stress Group, R. Alfredo Allen, 4200-135 Porto, Portugal
| | - Daniela Weber
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; NutriAct - Competence Cluster Nutrition Research Berlin-Potsdam, 14558 Nuthetal, Germany
| | - Annika Höhn
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany; German Center for Cardiovascular Research (DZHK), 10117 Berlin, Germany; NutriAct - Competence Cluster Nutrition Research Berlin-Potsdam, 14558 Nuthetal, Germany
| | - Tobias Jung
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Cardiovascular Research (DZHK), 10117 Berlin, Germany.
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Karpova YD, Bozhok GA, Alabedal’karim NM, Lyupina YV, Astakhova TM, Legach EI, Sharova NP. Proteasomes and transplantology: Current state of the problem and the search for promising trends. BIOL BULL+ 2017. [DOI: 10.1134/s1062359017030049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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PA28 modulates antigen processing and viral replication during coxsackievirus B3 infection. PLoS One 2017; 12:e0173259. [PMID: 28278207 PMCID: PMC5344377 DOI: 10.1371/journal.pone.0173259] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/17/2017] [Indexed: 11/19/2022] Open
Abstract
The function of the proteasome is modulated at the level of subunit expression and by association with its regulatory complexes. During coxsackievirus B3 (CVB3) myocarditis, IFN-induced formation of immunoproteasomes (ip) is known to be critical for regulating immune modulating molecules. The function of the IFN-γ-inducible proteasome regulator subunits PA28 α and β, however, in this context was unknown. During viral myocarditis, we found an increased abundance of PA28β subunits in heart tissue. PA28α/β exists in PA28-20S-PA28 and PA700-20S-PA28 hybrid proteasome complexes in cells both with either predominant ip and standard proteasome (sp) expression. Being in line with reduced proteasome activity in PA28α/β-deficient cells, we observed increased levels of oxidized and poly-ubiquitinated proteins upon TLR3-activation in these cells. Moreover, PA28α/β is capable to interfere directly with viral replication of CVB3 and facilitates the generation of CVB3-derived MHC class I epitopes by the proteasome. In contrast to a distinct function of PA28α/β in vitro, gene ablation of PA28α/β in mice being on a genetic background with resistance towards the development of severe infection had no significant impact on disease progression. Other than reported for the ip, in this host PA28α/β is dispensable to meet the demand of increased peptide hydrolysis capacity by the proteasome during viral myocarditis.
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Raynes R, Pomatto LCD, Davies KJA. Degradation of oxidized proteins by the proteasome: Distinguishing between the 20S, 26S, and immunoproteasome proteolytic pathways. Mol Aspects Med 2016; 50:41-55. [PMID: 27155164 DOI: 10.1016/j.mam.2016.05.001] [Citation(s) in RCA: 153] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 03/29/2016] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
Abstract
The proteasome is a ubiquitous and highly plastic multi-subunit protease with multi-catalytic activity that is conserved in all eukaryotes. The most widely known function of the proteasome is protein degradation through the 26S ubiquitin-proteasome system, responsible for the vast majority of protein degradation during homeostasis. However, the proteasome also plays an important role in adaptive immune responses and adaptation to oxidative stress. The unbound 20S proteasome, the core common to all proteasome conformations, is the main protease responsible for degrading oxidized proteins. During periods of acute stress, the 19S regulatory cap of the 26S proteasome disassociates from the proteolytic core, allowing for immediate ATP/ubiquitin-independent protein degradation by the 20S proteasome. Despite the abundance of unbound 20S proteasome compared to other proteasomal conformations, many publications fail to distinguish between the two proteolytic systems and often regard the 26S proteasome as the dominant protease. Further confounding the issue are the differential roles these two proteolytic systems have in adaptation and aging. In this review, we will summarize the increasing evidence that the 20S core proteasome constitutes the major conformation of the proteasome system and that it is far from a latent protease requiring activation by binding regulators.
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Affiliation(s)
- Rachel Raynes
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, The University of Southern California, Los Angeles, CA 90089-0191, USA; Division of Molecular and Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Laura C D Pomatto
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, The University of Southern California, Los Angeles, CA 90089-0191, USA; Division of Molecular and Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Kelvin J A Davies
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, The University of Southern California, Los Angeles, CA 90089-0191, USA; Division of Molecular and Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, CA 90089-0191, USA.
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Caputi FF, Carboni L, Mazza D, Candeletti S, Romualdi P. Cocaine and ethanol target 26S proteasome activity and gene expression in neuroblastoma cells. Drug Alcohol Depend 2016; 161:265-75. [PMID: 26922280 DOI: 10.1016/j.drugalcdep.2016.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/26/2016] [Accepted: 02/05/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Ethanol and cocaine are widely abused drugs triggering long-lasting changes in neuronal circuits and synaptic transmission through the regulation of enzyme activity and gene expression. Compelling evidence indicates that the ubiquitin-proteasome system plays a role in the molecular changes induced by addictive substances, impacting on several mechanisms implicated in abuse. The goal of these studies was to evaluate the effects of cocaine or ethanol on proteasome activity in neuroblastoma cells. Moreover, the gene expression of specific subunits was assessed. METHODS Chymotrypsin-like activity was measured after 2 h, 24 h, and 48 h exposure to 5 μM cocaine or 40 mM ethanol. Proteasome subunit transcripts were evaluated by qPCR at the same time-points. RESULTS Treatments modified proteasome function in opposite directions, since cocaine increased and ethanol reduced chymotrypsin-like activity. Interestingly, we observed gene expression alterations induced by these drugs. In the core particle, the β1 and α5 subunits were mainly up-regulated by cocaine, whereas α6 transcripts were mostly decreased. β2 and β5 did not change. Similarly, ethanol exposure generally increased β1 and α5 mRNAs. Moreover, the β2 subunit was significantly up-regulated by ethanol only. The β5 and α6 subunits were not altered. In the regulatory particle, Rpt3 was increased by cocaine exposure, whereas it was reduced by ethanol. No significant Rpn9 alterations were observed. CONCLUSIONS These findings support the notion that addictive substances regulate proteasome function, contributing to the dysregulations related to drug abuse since the availability of adequate subunit amounts is necessary for proper complex assembly and function.
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Affiliation(s)
- Francesca Felicia Caputi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy.
| | - Lucia Carboni
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy
| | - Daria Mazza
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy
| | - Sanzio Candeletti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Irnerio 48, 40126 Bologna, Italy
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