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Mechanisms of HIV protein degradation into epitopes: implications for vaccine design. Viruses 2014; 6:3271-92. [PMID: 25196483 PMCID: PMC4147695 DOI: 10.3390/v6083271] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/06/2014] [Accepted: 08/11/2014] [Indexed: 12/02/2022] Open
Abstract
The degradation of HIV-derived proteins into epitopes displayed by MHC-I or MHC-II are the first events leading to the priming of HIV-specific immune responses and to the recognition of infected cells. Despite a wealth of information about peptidases involved in protein degradation, our knowledge of epitope presentation during HIV infection remains limited. Here we review current data on HIV protein degradation linking epitope production and immunodominance, viral evolution and impaired epitope presentation. We propose that an in-depth understanding of HIV antigen processing and presentation in relevant primary cells could be exploited to identify signatures leading to efficient or inefficient epitope presentation in HIV proteomes, and to improve the design of immunogens eliciting immune responses efficiently recognizing all infected cells.
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152
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Wang C, Wang X. The interplay between autophagy and the ubiquitin-proteasome system in cardiac proteotoxicity. Biochim Biophys Acta Mol Basis Dis 2014; 1852:188-94. [PMID: 25092168 DOI: 10.1016/j.bbadis.2014.07.028] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/07/2014] [Accepted: 07/28/2014] [Indexed: 12/11/2022]
Abstract
Proteotoxicity refers to the detrimental effects of damaged/misfolded proteins on the cell. Cardiac muscle is particularly susceptible to proteotoxicity because sustained and severe proteotoxic stress leads to cell death and the cardiac muscle has very limited self-renewal capacity. The ubiquitin-proteasome system (UPS) and the autophagic-lysosomal pathway (ALP) are two major pathways responsible for degradation of most cellular proteins. Alterations of UPS and ALP functions are associated with the accumulation of proteotoxic species in the heart, a key pathological feature of common forms of heart disease including idiopathic, ischemic, and pressure-overloaded cardiomyopathies and a large subset of congestive heart failure. Emerging evidence suggests that proteasome inhibition or impairment activates autophagy and conversely, acute ALP inhibition may sometimes increase intrinsic proteasome peptidase activities but chronic ALP inhibition hinders UPS performance in ubiquitinated protein degradation. The exact molecular basis on which the two degradative pathways interact remains largely undefined. Here we review current understanding of the roles of the UPS and autophagy in the control of cardiac proteotoxicity, with a specific focus on the crosstalk between the two pathways. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases.
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Affiliation(s)
- Changhua Wang
- Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, Vermillion, SD 57069, USA
| | - Xuejun Wang
- Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, Vermillion, SD 57069, USA.
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153
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Bai M, Zhao X, Sahara K, Ohte Y, Hirano Y, Kaneko T, Yashiroda H, Murata S. Assembly mechanisms of specialized core particles of the proteasome. Biomolecules 2014; 4:662-77. [PMID: 25033340 PMCID: PMC4192667 DOI: 10.3390/biom4030662] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/30/2014] [Accepted: 06/22/2014] [Indexed: 11/16/2022] Open
Abstract
The 26S proteasome has a highly complicated structure comprising the 20S core particle (CP) and the 19S regulatory particle (RP). Along with the standard CP in all eukaryotes, vertebrates have two more subtypes of CP called the immunoproteasome and the thymoproteasome. The immunoproteasome has catalytic subunits β1i, β2i, and β5i replacing β1, β2, and β5 and enhances production of major histocompatibility complex I ligands. The thymoproteasome contains thymus-specific subunit β5t in place of β5 or β5i and plays a pivotal role in positive selection of CD8+ T cells. Here we investigate the assembly pathways of the specialized CPs and show that β1i and β2i are incorporated ahead of all the other β-subunits and that both β5i and β5t can be incorporated immediately after the assembly of β3 in the absence of β4, distinct from the assembly of the standard CP in which β-subunits are incorporated in the order of β2, β3, β4, β5, β6, β1, and β7. The propeptide of β5t is a key factor for this earlier incorporation, whereas the body sequence seems to be important for the earlier incorporation of β5i. This unique feature of β5t and β5i may account for preferential assembly of the immunoproteasome and the thymoproteasome over the standard type even when both the standard and specialized subunits are co-expressed.
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Affiliation(s)
- Minghui Bai
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Xian Zhao
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kazutaka Sahara
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuki Ohte
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuko Hirano
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Takeumi Kaneko
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Hideki Yashiroda
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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154
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Sharova NP, Sumedi IR, Astakhova TM, Plekhanova AS, Lyupina YV, Shashova EE, Kondakova IV, Rodoman GV. Diagnostics of thyroid cancer: Limitations of the existing methods and perspectives for future developments. BIOL BULL+ 2014. [DOI: 10.1134/s1062359014040104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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155
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Jiang H, Clise-Dwyer K, Ruisaard KE, Fan X, Tian W, Gumin J, Lamfers ML, Kleijn A, Lang FF, Yung WKA, Vence LM, Gomez-Manzano C, Fueyo J. Delta-24-RGD oncolytic adenovirus elicits anti-glioma immunity in an immunocompetent mouse model. PLoS One 2014; 9:e97407. [PMID: 24827739 PMCID: PMC4020829 DOI: 10.1371/journal.pone.0097407] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/16/2014] [Indexed: 11/23/2022] Open
Abstract
Background Emerging evidence suggests anti-cancer immunity is involved in the therapeutic effect induced by oncolytic viruses. Here we investigate the effect of Delta-24-RGD oncolytic adenovirus on innate and adaptive anti-glioma immunity. Design Mouse GL261-glioma model was set up in immunocompetent C57BL/6 mouse for Delta-24-RGD treatment. The changes of the immune cell populations were analyzed by immunohistochemistry and flow cytometry. The anti-glioma immunity was evaluated with functional study of the splenocytes isolated from the mice. The efficacy of the virotherapy was assessed with animal survival analysis. The direct effect of the virus on the tumor-associated antigen presentation to CD8+ T cells was analyzed with an in vitro ovalbumin (OVA) modeling system. Results Delta-24-RGD induced cytotoxic effect in mouse glioma cells. Viral treatment in GL261-glioma bearing mice caused infiltration of innate and adaptive immune cells, instigating a Th1 immunity at the tumor site which resulted in specific anti-glioma immunity, shrunken tumor and prolonged animal survival. Importantly, viral infection and IFNγ increased the presentation of OVA antigen in OVA-expressing cells to CD8+ T-cell hybridoma B3Z cells, which is blocked by brefeldin A and proteasome inhibitors, indicating the activity is through the biosynthesis and proteasome pathway. Conclusions Our results demonstrate that Delta-24-RGD induces anti-glioma immunity and offers the first evidence that viral infection directly enhances presentation of tumor-associated antigens to immune cells.
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Affiliation(s)
- Hong Jiang
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- * E-mail:
| | - Karen Clise-Dwyer
- Department of Stem Cell Transplantation, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Kathryn E. Ruisaard
- Department of Stem Cell Transplantation, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Xuejun Fan
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Weihua Tian
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Joy Gumin
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | | | - Anne Kleijn
- Department of Neurosurgery, Erasmus MC, Rotterdam, The Netherlands
| | - Frederick F. Lang
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Wai-Kwan Alfred Yung
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Luis M. Vence
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Candelaria Gomez-Manzano
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Juan Fueyo
- Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
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156
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Rasid O, Meulenbroeks C, Gröne A, Zaiss D, Sijts A. Enhanced inflammatory potential of CD4+ T-cells that lack proteasome immunosubunit expression, in a T-cell transfer-based colitis model. PLoS One 2014; 9:e95378. [PMID: 24740379 PMCID: PMC3989320 DOI: 10.1371/journal.pone.0095378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 03/26/2014] [Indexed: 11/19/2022] Open
Abstract
Proteasomes play a fundamental role in intracellular protein degradation and therewith regulate a variety of cellular processes. Exposure of cells to (pro)inflammatory cytokines upregulates the expression of three inducible catalytic proteasome subunits, the immunosubunits, which incorporate into newly assembled proteasome complexes and alter the catalytic activity of the cellular proteasome population. Single gene-deficient mice lacking one of the three immunosubunits are resistant to dextran sulfate sodium (DSS)-induced colitis development and, likewise, inhibition of one single immunosubunit protects mice against the development of DSS-induced colitis. The observed diminished disease susceptibility has been attributed to altered cytokine production and CD4+ T-cell differentiation in the absence of immunosubunits. To further test whether the catalytic activity conferred by immunosubunits plays an essential role in CD4+ T-cell function and to distinguish between the role of immunosubunits in effector T-cells versus inflamed tissue, we used a T-cell transfer-induced colitis model. Naïve wt or immunosubunit-deficient CD4+ T-cells were adoptively transferred into RAG1-/- and immunosubunit-deficient RAG1-/- mice and colitis development was determined six weeks later. While immunosubunit expression in recipient mice had no effect on colitis development, transferred immunosubunit-deficient T- cells were more potent in inducing colitis and produced more proinflammatory IL17 than wt T-cells. Taken together, our data show that modifications in proteasome-mediated proteolysis in T-cells, conferred by lack of immunosubunit incorporation, do not attenuate but enhance CD4+ T-cell-induced inflammation.
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Affiliation(s)
- Orhan Rasid
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands
| | - Chantal Meulenbroeks
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands
| | - Andrea Gröne
- Department of Pathology, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands
| | - Dietmar Zaiss
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands
- * E-mail: (AS); (DZ)
| | - Alice Sijts
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands
- * E-mail: (AS); (DZ)
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157
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Karpova ID, Lyupina IV, Astakhova TM, Stepanova AA, Erokhov PA, Abramova EB, Sharova NP. [Immune proteasomes in the development of rat immune system]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2014; 39:400-10. [PMID: 24707720 DOI: 10.1134/s1068162013040092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The dynamics of the expression of LMP7 and LMP2 proteasome subunits in embryonic and early postnatal development of rat spleen and liver is investigated in comparison with the dynamics of chymotrypsin-like and caspase-like proteasome activities and expression of MHC (major histocompatibility complex) class I molecules. The immune subunits LMP7 and LMP2 distribution in spleen and liver cells in the development process is also studied. A mutual for both organs tendency to the increase of the expression of both LMP7 subunit and LMP2 one on P21 (the 21st postnatal day) as compared to the embryonic period is discovered. However, the total proteasome level is shown to be constant. At definite development stages, the dynamics of immune subunits expression in the spleen and liver was different. In the spleen gradual enhancement of both immune subunits level being detected on P1, P18 and P21, in the liver gradual enhancement periods on E16 (the 16th embryonic day) and E18 changed to the stage of the shrink of immune subunits level on P5. This level did not reliably change till P18 and was augmented on P21. The alterations revealed were accompanied by chymotrypsin-like activity raise and caspase-like activity drop in spleen by P21 as compared with the embryonic period, which proves the enlargement of proteasome ability to form antigenic epitopes for MHC class I molecules. In the liver, both activities increased by P21 in comparison with the embryonic period. Such dynamics of caspase-like activity can be explained not only by the change of proteolytic constitutive and immune subunits, but also by additional regulatory mechanisms. Besides, it is discovered that the increment of immune subunits expression in the early spleen development is connected with the process of successive forming the white pulp by B- and T-lymphocytes enriched by immune subunits. In the liver, the growth of immune subunits level by P21 was accompanied by their expression expansion in hepatocytes, while their plunge by P5 may be related to the loss of liver function of a primary lymphoid organ of the immune system by this stage and disappearance of B-lymphocytes enriched by immune proteasomes in it. In the spleen and liver, MHC class I molecules were revealed at the periods of the raise of proteasome immune subunits level. On E21 , the liver was enriched by neuronal NO-synthase, its level decreased after birth and enhanced to P18. This fact indicates the possibility of the induction of the immune subunits LMP7 [character: see text] LMP2 expression in hepatocytes in signal way with neuronal NO-synthase participation. The results obtained prove that T-cell immune response with spleen participation as regards rat liver cells is possible starting with P19-P21 stage. First, at this period, white pulp T-area is formed in the spleen. Second, enhanced immune proteasomes and MHC class I molecules levels in hepatocytes can procure antigenic epitopes formation from foreign proteins and their delivery to cell surface for their subsequent presentation for cytotoxic T-lymphocytes.
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158
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Souza LDC, Camargo R, Demasi M, Santana JM, de Sá CM, de Freitas SM. Effects of an anticarcinogenic Bowman-Birk protease inhibitor on purified 20S proteasome and MCF-7 breast cancer cells. PLoS One 2014; 9:e86600. [PMID: 24475156 PMCID: PMC3903573 DOI: 10.1371/journal.pone.0086600] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/11/2013] [Indexed: 01/01/2023] Open
Abstract
Proteasome inhibitors have been described as an important target for cancer therapy due to their potential to regulate the ubiquitin-proteasome system in the degradation pathway of cellular proteins. Here, we reported the effects of a Bowman-Birk-type protease inhibitor, the Black-eyed pea Trypsin/Chymotrypsin Inhibitor (BTCI), on proteasome 20S in MCF-7 breast cancer cells and on catalytic activity of the purified 20S proteasome from horse erythrocytes, as well as the structural analysis of the BTCI-20S proteasome complex. In vitro experiments and confocal microscopy showed that BTCI readily crosses the membrane of the breast cancer cells and co-localizes with the proteasome in cytoplasm and mainly in nucleus. Indeed, as indicated by dynamic light scattering, BTCI and 20S proteasome form a stable complex at temperatures up to 55°C and at neutral and alkaline pHs. In complexed form, BTCI strongly inhibits the proteolytic chymotrypsin-, trypsin- and caspase-like activities of 20S proteasome, indicated by inhibition constants of 10−7 M magnitude order. Besides other mechanisms, this feature can be associated with previously reported cytostatic and cytotoxic effects of BTCI in MCF-7 breast cancer cells by means of apoptosis.
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Affiliation(s)
- Larissa da Costa Souza
- Laboratory of Biophysics, Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Ricardo Camargo
- Laboratory of Microbiology Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Marilene Demasi
- Laboratory of Biochemistry and Biophysics, Butantan Institute, São Paulo, Brazil
| | - Jaime Martins Santana
- Laboratory of Pathogen-Host Interface, Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Cézar Martins de Sá
- Laboratory of Microbiology Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Sonia Maria de Freitas
- Laboratory of Biophysics, Department of Cellular Biology, University of Brasília, Brasília, Brazil
- * E-mail:
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159
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Stepanova AA, Karpova YD, Bozhok GA, Ustichenko VD, Lyupina YV, Legach EI, Vagida MS, Kazansky DB, Bondarenko TP, Sharova NP. [Proteasomes on thyroid tissue allotransplantation under induction of donor specific tolerance in rats]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2014; 40:42-54. [PMID: 25898722 DOI: 10.1134/s1068162014010105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The proteasomes in the liver of August rats (RT1C) were investigated 30 days after the allotransplantation of Wistar rat (RT1u) thyroid tissue under renal capsule with/without induction of donor specific tolerance by donor splenocyte intraportal administration. The level of the total proteasome pool, immune proteasomes containing the LMP2 and/or LMP7 subunits, proteasome 19S- and 11S-regulators was defined. The intact and sham-operated August rats were used as control groups. The level of all immune proteasome forms and 11S regulator increased while the level of the total proteasome pool and 19S regulator decreased in the liver of experimental animals compared to the control groups that indicated changes of liver functional state after transplantation. The 19S/11S ratio increased in the liver of non-tolerated rats compared to tolerated animals. In the liver of tolerated rats with survived transplants, the quantity of mononuclear cells, expressing the immune subunit LMP2, greatly increased in comparison with control and non-tolerated animals. Study of the survived transplants showed the increase of the ratio of LMP2/LMP7 immune subunits and 19S/11S regulators in them compared to the tissue replacing the rejected transplants. In the control intact thyroid tissue, the immune proteasomes were almost not revealed, while 19S/11S ratio was maximal. Thus, the development of the immune reaction or its suppression is accompanied by change of the balance between different proteasome forms. The immune subunit LMP7 and 11S regulator are connected with the response against donor tissue. On the contrary, the immune subunit LMP2 and 19S regulator are likely to be important for the immune tolerance development and survived tissue functioning. The low content of the immune proteasomes in the follicle cells was found by immunofluorescence assay. The formation of antigens for major histocompatibility complex class I molecules was impaired by low immune proteasome content that led to immunological tolerance to hormone-producing follicle cells.
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160
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Abstract
The proteasome is a sophisticated, 2.5-MDa, multisubunit complex that contains a catalytic core particle (CP) and two terminal regulatory particles (RPs); the RPs associate with the termini of the central CP at opposite orientations. The CP consists of four axially stacked heptameric rings (two outer α-rings and two inner β-rings), which are made up of seven structurally related, but not identical, α and β subunits. The CP contains catalytic threonine residues (in β1, β2, and β5 with caspase-like, trypsin-like, and chymotrypsin-like activities, respectively) on the surface of the chamber formed by two abutting β-rings. The RP recognizes polyubiquitylated substrate proteins and unfolds and translocates these proteins to the interior of the CP for degradation. The RP comprises 19 different subunits, which are thought to form two subcomplexes called the lid and the base. One longstanding question is how the complex structure of the proteasome is organized with high fidelity. Recently, we proposed a novel assembly mechanism that is assisted by multiple proteasome-dedicated chaperones. In addition, we discovered two immuno-type proteasomes, the immunoproteasome and the thymoproteasome, whose catalytic subunits are replaced by homologous counterparts. These two isoforms perform specialized functions that help discriminate self from non-self in cell-mediated immunity (i.e., they function as enzymes that process intracellular antigens for cytotoxic T lymphocyte responses and thymic positive selection). Moreover, emerging evidence suggests that the proteasome is crucially involved in the pathophysiology of various intractable diseases that are increasing in today's aging society.
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161
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Weathington NM, Sznajder JI, Mallampalli RK. The emerging role of the ubiquitin proteasome in pulmonary biology and disease. Am J Respir Crit Care Med 2013; 188:530-7. [PMID: 23713962 DOI: 10.1164/rccm.201304-0754pp] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Derangements in normal cellular homeostasis at the protein level can cause or be the consequence of initiation and progression of pulmonary diseases related to genotype, infection, injury, smoking, toxin exposure, or neoplasm. We discuss one of the fundamental mechanisms of protein homeostasis, the ubiquitin proteasome system (UPS), as it relates to lung disease. The UPS effects selective degradation of ubiquitinated target proteins via ubiquitin ligase activity. Important pathobiological mechanisms relating to the UPS and lung disease have been the focus of research, with inappropriate cellular proteolysis now a validated therapeutic target. We review the contributions of this system in various lung diseases, and discuss the exciting area of UPS-targeting drug development for pulmonary disease.
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Affiliation(s)
- Nathaniel M Weathington
- Acute Lung Injury Center of Excellence, Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pennsylvania, USA
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162
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Ferrington DA, Gregerson DS. Immunoproteasomes: structure, function, and antigen presentation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 109:75-112. [PMID: 22727420 DOI: 10.1016/b978-0-12-397863-9.00003-1] [Citation(s) in RCA: 299] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Immunoproteasomes contain replacements for the three catalytic subunits of standard proteasomes. In most cells, oxidative stress and proinflammatory cytokines are stimuli that lead to elevated production of immunoproteasomes. Immune system cells, especially antigen-presenting cells, express a higher basal level of immunoproteasomes. A well-described function of immunoproteasomes is to generate peptides with a hydrophobic C terminus that can be processed to fit in the groove of MHC class I molecules. This display of peptides on the cell surface allows surveillance by CD8 T cells of the adaptive immune system for pathogen-infected cells. Functions of immunoproteasomes, other than generating peptides for antigen presentation, are emerging from studies in immunoproteasome-deficient mice, and are complemented by recently described diseases linked to mutations or single-nucleotide polymorphisms in immunoproteasome subunits. Thus, this growing body of literature suggests a more pleiotropic role in cell function for the immunoproteasome.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology, University of Minnesota, Minneapolis, Minnesota, USA
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163
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Leone P, Shin EC, Perosa F, Vacca A, Dammacco F, Racanelli V. MHC class I antigen processing and presenting machinery: organization, function, and defects in tumor cells. J Natl Cancer Inst 2013; 105:1172-87. [PMID: 23852952 DOI: 10.1093/jnci/djt184] [Citation(s) in RCA: 388] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The surface presentation of peptides by major histocompatibility complex (MHC) class I molecules is critical to all CD8(+) T-cell adaptive immune responses, including those against tumors. The generation of peptides and their loading on MHC class I molecules is a multistep process involving multiple molecular species that constitute the so-called antigen processing and presenting machinery (APM). The majority of class I peptides begin as proteasome degradation products of cytosolic proteins. Once transported into the endoplasmic reticulum by TAP (transporter associated with antigen processing), peptides are not bound randomly by class I molecules but are chosen by length and sequence, with peptidases editing the raw peptide pool. Aberrations in APM genes and proteins have frequently been observed in human tumors and found to correlate with relevant clinical variables, including tumor grade, tumor stage, disease recurrence, and survival. These findings support the idea that APM defects are immune escape mechanisms that disrupt the tumor cells' ability to be recognized and killed by tumor antigen-specific cytotoxic CD8(+) T cells. Detailed knowledge of APM is crucial for the optimization of T cell-based immunotherapy protocols.
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Affiliation(s)
- Patrizia Leone
- Department of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy
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164
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Cell host response to infection with novel human coronavirus EMC predicts potential antivirals and important differences with SARS coronavirus. mBio 2013; 4:e00165-13. [PMID: 23631916 PMCID: PMC3663187 DOI: 10.1128/mbio.00165-13] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED A novel human coronavirus (HCoV-EMC) was recently identified in the Middle East as the causative agent of a severe acute respiratory syndrome (SARS) resembling the illness caused by SARS coronavirus (SARS-CoV). Although derived from the CoV family, the two viruses are genetically distinct and do not use the same receptor. Here, we investigated whether HCoV-EMC and SARS-CoV induce similar or distinct host responses after infection of a human lung epithelial cell line. HCoV-EMC was able to replicate as efficiently as SARS-CoV in Calu-3 cells and similarly induced minimal transcriptomic changes before 12 h postinfection. Later in infection, HCoV-EMC induced a massive dysregulation of the host transcriptome, to a much greater extent than SARS-CoV. Both viruses induced a similar activation of pattern recognition receptors and the interleukin 17 (IL-17) pathway, but HCoV-EMC specifically down-regulated the expression of several genes within the antigen presentation pathway, including both type I and II major histocompatibility complex (MHC) genes. This could have an important impact on the ability of the host to mount an adaptive host response. A unique set of 207 genes was dysregulated early and permanently throughout infection with HCoV-EMC, and was used in a computational screen to predict potential antiviral compounds, including kinase inhibitors and glucocorticoids. Overall, HCoV-EMC and SARS-CoV elicit distinct host gene expression responses, which might impact in vivo pathogenesis and could orient therapeutic strategies against that emergent virus. IMPORTANCE Identification of a novel coronavirus causing fatal respiratory infection in humans raises concerns about a possible widespread outbreak of severe respiratory infection similar to the one caused by SARS-CoV. Using a human lung epithelial cell line and global transcriptomic profiling, we identified differences in the host response between HCoV-EMC and SARS-CoV. This enables rapid assessment of viral properties and the ability to anticipate possible differences in human clinical responses to HCoV-EMC and SARS-CoV. We used this information to predict potential effective drugs against HCoV-EMC, a method that could be more generally used to identify candidate therapeutics in future disease outbreaks. These data will help to generate hypotheses and make rapid advancements in characterizing this new virus.
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165
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Timofeev AV, Kuzmenko YV, Zharkova II, Starodubova ES, Karpov VL. Activation of transcription of immunoproteasome subunit genes in murine monocytes infected with different mycobacterial strains. Mol Biol 2013. [DOI: 10.1134/s0026893313020155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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166
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Volkov A, Hagner S, Löser S, Alnahas S, Raifer H, Hellhund A, Garn H, Steinhoff U. β5i subunit deficiency of the immunoproteasome leads to reduced Th2 response in OVA induced acute asthma. PLoS One 2013; 8:e60565. [PMID: 23593249 PMCID: PMC3617144 DOI: 10.1371/journal.pone.0060565] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/27/2013] [Indexed: 11/22/2022] Open
Abstract
The immunoproteasome subunit β5i has been shown to play an important role in Th1/Th17 driven models of colitis and arthritis. However, the function of β5i in Th2 dependent diseases remains enigmatic. To study the role of β5i in Th2-driven pathology, β5i knockout (KO) and control mice were tested in different models of experimental allergic asthma. β5i-deficient mice showed reduced OVA/Alum- and subcutaneous/OVA-induced acute asthma with decreased eosinophilia in the bronchoalveolar lavage (BAL), low OVA-specific IgG1 and reduced local and systemic Th2 cytokines. While Th2 cells in the lungs were reduced, Tregs and Th1 cells were not affected. Attenuated asthma in β5i KO mice could not be attributed to defects in OVA uptake or maturation of dendritic cells in the lung. Surprisingly, β5i deficient mice developed HDM asthma which was comparable to control mice. Here, we present novel evidence for the requirement of the β5i immunosubunit to generate a strong Th2 response during OVA- but not HDM-induced acute asthma. The unexpected role of β5i in OVA asthma remains to be clarified.
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Affiliation(s)
- Anton Volkov
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany
| | - Stefanie Hagner
- Institute for Laboratory Medicine and Pathobiochemistry, Philipps University of Marburg, Marburg, Germany
| | - Stephan Löser
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany
| | - Safa Alnahas
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany
| | - Hartmann Raifer
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany
| | - Anne Hellhund
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany
| | - Holger Garn
- Institute for Laboratory Medicine and Pathobiochemistry, Philipps University of Marburg, Marburg, Germany
| | - Ulrich Steinhoff
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany
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167
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Lilienbaum A. Relationship between the proteasomal system and autophagy. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 4:1-26. [PMID: 23638318 PMCID: PMC3627065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/27/2013] [Indexed: 06/02/2023]
Abstract
TWO MAJOR PATHWAYS DEGRADE MOST CELLULAR PROTEINS IN EUKARYOTIC CELLS: the ubiquitin-proteasome system (UPS), which usually degrades the majority of proteins, and autophagy, primarily responsible for the degradation of most long-lived or aggregated proteins and cellular organelles. Disruption of these processes can contribute to pathology of a variety of diseases. Further, both pathways are critical for the maintenance of several aspects of cellular homeostasis, but, until recently, were thought to be largely distinct. Recent advances in this field, however, now strongly suggest that their activities are carefully orchestrated through several interfacing elements that are presented and discussed in this review.
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Affiliation(s)
- Alain Lilienbaum
- Laboratory of Stress and Pathologies of the Cytoskeleton, Unit of Functional and Adaptive Biology (BFA) affiliated with CNRS (EAC4413), University Paris Diderot-Paris 7 75250 Paris Cedex 13, France
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168
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Duan X, Imai T, Chou B, Tu L, Himeno K, Suzue K, Hirai M, Taniguchi T, Okada H, Shimokawa C, Hisaeda H. Resistance to malaria by enhanced phagocytosis of erythrocytes in LMP7-deficient mice. PLoS One 2013; 8:e59633. [PMID: 23527234 PMCID: PMC3602297 DOI: 10.1371/journal.pone.0059633] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/15/2013] [Indexed: 12/18/2022] Open
Abstract
General cellular functions of proteasomes occur through protein degradation, whereas the specific function of immunoproteasomes is the optimization of antigen processing associated with MHC class I. We and others previously reported that deficiency in subunits of immunoproteasomes impaired the activation of antigen-specific CD8+ T cells, resulting in higher susceptibility to tumor and infections. We demonstrated that CD8+ T cells contributed to protection against malaria parasites. In this study, we evaluated the role of immunoproteasomes in the course of infection with rodent malaria parasites. Unexpectedly, Plasmodium yoelii infection of mice deficient in LMP7, a catalytic subunit of immunoproteasomes, showed lower parasite growth in the early phase of infection and lower lethality compared with control mice. The protective characteristics of LMP7-deficient mice were not associated with enhanced immune responses, as the mutant mice showed comparable or diminished activation of innate and acquired immunity. The remarkable difference was observed in erythrocytes instead of immune responses. Parasitized red blood cells (pRBCs) purified from LMP7-deficient mice were more susceptible to phagocytosis by macrophages compared with those from wild-type mice. The susceptibility of pRBC to phagocytosis appeared to correlate with deformity of the membrane structures that were only observed after infection. Our results suggest that RBCs of LMP7-deficient mice were more likely to deform in response to infection with malaria parasites, presumably resulting in higher susceptibility to phagocytosis and in the partial resistance to malaria.
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Affiliation(s)
- Xuefeng Duan
- Department of Parasitology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takashi Imai
- Department of Parasitology, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Bin Chou
- Department of Parasitology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Liping Tu
- Department of Parasitology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kunisuke Himeno
- Department of Parasitology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazutomo Suzue
- Department of Parasitology, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Makoto Hirai
- Department of Parasitology, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Tomoyo Taniguchi
- Department of Parasitology, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Hiroko Okada
- Department of Parasitology, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Chikako Shimokawa
- Department of Parasitology, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Hajime Hisaeda
- Department of Parasitology, Graduate School of Medicine, Gunma University, Maebashi, Japan
- * E-mail:
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169
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Kunjappu MJ, Hochstrasser M. Assembly of the 20S proteasome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:2-12. [PMID: 23507199 DOI: 10.1016/j.bbamcr.2013.03.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/02/2013] [Accepted: 03/05/2013] [Indexed: 10/27/2022]
Abstract
The proteasome is a cellular protease responsible for the selective degradation of the majority of the intracellular proteome. It recognizes, unfolds, and cleaves proteins that are destined for removal, usually by prior attachment to polymers of ubiquitin. This macromolecular machine is composed of two subcomplexes, the 19S regulatory particle (RP) and the 20S core particle (CP), which together contain at least 33 different and precisely positioned subunits. How these subunits assemble into functional complexes is an area of active exploration. Here we describe the current status of studies on the assembly of the 20S proteasome (CP). The 28-subunit CP is found in all three domains of life and its cylindrical stack of four heptameric rings is well conserved. Though several CP subunits possess self-assembly properties, a consistent theme in recent years has been the need for dedicated assembly chaperones that promote on-pathway assembly. To date, a minimum of three accessory factors have been implicated in aiding the construction of the 20S proteasome. These chaperones interact with different assembling proteasomal precursors and usher subunits into specific slots in the growing structure. This review will focus largely on chaperone-dependent CP assembly and its regulation. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- Mary J Kunjappu
- Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue P.O. Box 208114, New Haven, CT 06520-8114, USA
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170
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Martinez-Gamboa L, Lesemann K, Kuckelkorn U, Scheffler S, Ghannam K, Hahne M, Gaber-Elsner T, Egerer K, Naumann L, Buttgereit F, Dörner T, Kloetzel PM, Burmester GR, Faustman DL, Feist E. Gene expression of catalytic proteasome subunits and resistance toward proteasome inhibition of B lymphocytes from patients with primary sjogren syndrome. J Rheumatol 2013; 40:663-73. [PMID: 23504381 DOI: 10.3899/jrheum.120680] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Dysregulation of proteasome subunit β1i expression has been shown in total blood mononuclear cells (PBMC) from patients with primary Sjögren syndrome (pSS), a B cell-driven systemic autoimmune disorder. METHODS Proteasome activation was investigated in sorted blood cells from patients with pSS and controls by measuring transcript levels of constitutive (β1/β2/β5) and corresponding immunoproteasome catalytic subunits (β1i/β2i/β5i) using real-time PCR. At protein level, β1i protein expression was analyzed by immunoblotting. Functional effects of proteasome inhibition on proteolytic activity and induction of apoptosis were also evaluated in cellular subsets. RESULTS The proteasome was found to be activated in pSS, with upregulation of gene expression of catalytic proteasome subunits. Western blot analysis revealed decreased β1i protein expression in pSS B lymphocytes, with decreased protein despite increased messenger RNA (mRNA) levels. After proteasome inhibition in vitro, proteolytic activity was less reduced and resistance to apoptosis was increased in B lymphocytes compared to other cells. CONCLUSION In pSS, catalytic subunits of the proteasome are upregulated at the mRNA level, while dysregulation of subunit β1i is attributed to B lymphocytes. B cell resistance after proteasome inhibition differs from the classical concept of increased susceptibility toward inhibition in activated cells, supporting the novel notion that susceptibility depends on cellular intrinsic factors and on proteasome activation.
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Affiliation(s)
- Lorena Martinez-Gamboa
- Rheumatology Research Laboratory, Department of Rheumatology and Clinical Immunology, Charite Universitätsmedizin Berlin, Germany.
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171
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Abstract
The eukaryotic ubiquitin-proteasome system is responsible for most aspects of regulatory and quality-control protein degradation in cells. Its substrates, which are usually modified by polymers of ubiquitin, are ultimately degraded by the 26S proteasome. This 2.6-MDa protein complex is separated into a barrel-shaped proteolytic 20S core particle (CP) of 28 subunits capped on one or both ends by a 19S regulatory particle (RP) comprising at least 19 subunits. The RP coordinates substrate recognition, removal of substrate polyubiquitin chains, and substrate unfolding and translocation into the CP for degradation. Although many atomic structures of the CP have been determined, the RP has resisted high-resolution analysis. Recently, however, a combination of cryo-electron microscopy, biochemical analysis, and crystal structure determination of several RP subunits has yielded a near-atomic-resolution view of much of the complex. Major new insights into chaperone-assisted proteasome assembly have also recently emerged. Here we review these novel findings.
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Affiliation(s)
- Robert J Tomko
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
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172
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Gómez E, Caamaño JN, Corrales FJ, Díez C, Correia-Álvarez E, Martín D, Trigal B, Carrocera S, Mora MI, Pello-Palma J, Moreno JF, Muñoz M. Embryonic sex induces differential expression of proteins in bovine uterine fluid. J Proteome Res 2013; 12:1199-1210. [PMID: 23379789 DOI: 10.1021/pr300845e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bovine endometrium recognizes early embryos and reacts differently depending on the developmental potential of the embryo. However, it is unknown whether the endometrium can distinguish embryonic sex. Our objective was to analyze sexual dimorphism in the uterus in response to male and female embryos. Differentially expressed (DE) proteins, different levels of hexoses, and other embryotrophic differences were analyzed in uterine fluid (UF). Proteomic analysis of day-8 UF recovered from heifers after the transfer of day-5 male or female embryos identified 23 DE proteins. Regulated proteasome/immunoproteasome protein subunits indicated differences in antigen processing between UF carrying male embryos (male-UF) or female embryos (female-UF). Several enzymes involved in glycolysis/gluconeogenesis and antioxidative/antistress responses were up-regulated in female-UF. Fructose concentration was increased in female-UF versus male-UF, while glucose levels were similar. In vitro cultures with molecules isolated from male-UF were found to improve male embryo development compared to female embryos cultured with molecules isolated from female-UF. We postulated that, in vivo, male embryos induce changes in the endometrium to help ensure their survival. In contrast, female embryos do not appear to induce these changes.
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Affiliation(s)
- Enrique Gómez
- Centro de Biotecnología Animal-SERIDA, Camino de Rioseco 1225, La Olla-Deva, 33394 Gijón, Asturias, Spain
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173
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Maldonado M, Kapphahn RJ, Terluk MR, Heuss ND, Yuan C, Gregerson DS, Ferrington DA. Immunoproteasome deficiency modifies the alternative pathway of NFκB signaling. PLoS One 2013; 8:e56187. [PMID: 23457524 PMCID: PMC3572990 DOI: 10.1371/journal.pone.0056187] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 01/10/2013] [Indexed: 11/19/2022] Open
Abstract
Immunoproteasome is a protease abundant in immune cells and also present, albeit at lower concentrations, in cells outside the immune system. Recent evidence supports a novel role for the immunoproteasome in the cellular stress response potentially through regulation of NFκB signaling, which is the primary response to multiple stressors. The current study tests whether the Classical or Alternative Pathways are regulated by immunoproteasome following chronic TNFα exposure in cultured retinal pigment epithelial cells isolated from wild-type mice and mice deficient in one (LMP2, L2) or two (LMP7 and MECL-1, L7M1) immunoproteasome subunits. Assays were performed to assess the expression of NFκB responsive genes, the content and activity of NFκB transcription factors (p65, p50, p52, cRel, RelB), and expression and content of regulatory proteins (IκBα, A20, RPS3). Major findings include distinct differences in expression of NFκB responsive genes in both KO cells. The mechanism responsible for the altered gene expression could not be established for L7M1 since no major differences in NFκB transcription factor content or activation were observed. However, L2 cells exhibited substantially higher content and diminished activation of NFκB transcription factors associated with the Alternative Pathway and delayed termination of the Classical Pathway. These results provide strong experimental evidence supporting a role for immunoproteasome in modulating NFκB signaling.
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Affiliation(s)
- Marcela Maldonado
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Marcia R. Terluk
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Neal D. Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Ching Yuan
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dale S. Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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174
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Nooka A, Gleason C, Casbourne D, Lonial S. Relapsed and refractory lymphoid neoplasms and multiple myeloma with a focus on carfilzomib. Biologics 2013; 7:13-32. [PMID: 23386784 PMCID: PMC3563316 DOI: 10.2147/btt.s24580] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Proteasomal inhibition revolutionized myeloma therapies in this decade of novel agents. The only US Food and Drug Administration approved proteasome inhibitor so far, bortezomib effectively targets the constitutive proteasome subunit β5 of the 26S proteasome. Bortezomib induces high and quality response rates that are durable. However, myeloma cells acquire resistance to bortezomib through various mechanisms. Further, grade 3/4 peripheral neuropathy is seen in up to a quarter of patients treated with bortezomib. While the recent change in the mode of administration via the subcutaneous route is associated with a lower incidence of grade 3/4 peripheral neuropathy, it remains a major concern. The second generation proteasome inhibitors are promising, with increased preclinical efficacy and a better administration schedule. The current review spotlights the second generation proteasome inhibitors with special focus on the safety and efficacy of carfilzomib, an epoxyketone with lesser peripheral neuropathy, which exhibits irreversible proteasome inhibition. In this article, we review the pharmacology and preclinical and clinical efficacy and safety of carfilzomib alone and in combination with other chemotherapeutic agents in the various lymphoid neoplasms and multiple myeloma as well as ongoing clinical trials.
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Affiliation(s)
- Ajay Nooka
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta GA, USA
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175
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Höhn A, König J, Grune T. Protein oxidation in aging and the removal of oxidized proteins. J Proteomics 2013; 92:132-59. [PMID: 23333925 DOI: 10.1016/j.jprot.2013.01.004] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 01/08/2013] [Indexed: 12/12/2022]
Abstract
Reactive oxygen species (ROS) are generated constantly within cells at low concentrations even under physiological conditions. During aging the levels of ROS can increase due to a limited capacity of antioxidant systems and repair mechanisms. Proteins are among the main targets for oxidants due to their high rate constants for several reactions with ROS and their abundance in biological systems. Protein damage has an important influence on cellular viability since most protein damage is non-repairable, and has deleterious consequences on protein structure and function. In addition, damaged and modified proteins can form cross-links and provide a basis for many senescence-associated alterations and may contribute to a range of human pathologies. Two proteolytic systems are responsible to ensure the maintenance of cellular functions: the proteasomal (UPS) and the lysosomal system. Those degrading systems provide a last line of antioxidative protection, removing irreversible damaged proteins and recycling amino acids for the continuous protein synthesis. But during aging, both systems are affected and their proteolytic activity declines significantly. Here we highlight the recent advantages in the understanding of protein oxidation and the fate of these damaged proteins during aging. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine.
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Affiliation(s)
- Annika Höhn
- Department of Nutritional Toxicology, Institute of Nutrition, Friedrich Schiller University Jena, 07743 Jena, Germany
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176
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The immunoproteasome in antigen processing and other immunological functions. Curr Opin Immunol 2012; 25:74-80. [PMID: 23219269 DOI: 10.1016/j.coi.2012.11.004] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 11/12/2012] [Accepted: 11/13/2012] [Indexed: 01/30/2023]
Abstract
Treatment of cells with interferon-γ leads to the replacement of the constitutive catalytic proteasome subunits β1, β2, and β5 by the inducible subunits LMP2 (β1i), MECL-1 (β2i), and LMP7 (β5i), respectively, building the so-called immunoproteasome. The incorporation of these subunits is required for the production of numerous MHC class-I restricted T cell epitopes. Recently, new evidence for an involvement of the immunoproteasome in other facets of the immune response emerged. Investigations of autoimmune diseases in animal models and a genetic predisposition of β5i in human autoimmune disorders suggest a crucial function of the immunoproteasome in proinflammatory diseases. The recent elucidation of the high-resolution structure of the immunoproteasome will facilitate the design of immunoproteasome selective inhibitors for pharmacological intervention.
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177
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Kramer HB, Nicholson B, Kessler BM, Altun M. Detection of ubiquitin-proteasome enzymatic activities in cells: application of activity-based probes to inhibitor development. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1823:2029-37. [PMID: 22613766 PMCID: PMC7125640 DOI: 10.1016/j.bbamcr.2012.05.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/04/2012] [Accepted: 05/11/2012] [Indexed: 01/10/2023]
Abstract
BACKGROUND Synthetic probes that mimic natural substrates can enable the detection of enzymatic activities in a cellular environment. One area where such activity-based probes have been applied is the ubiquitin-proteasome pathway, which is emerging as an important therapeutic target. A family of reagents has been developed that specifically label deubiquitylating enzymes (DUBs) and facilitate characterization of their inhibitors. SCOPE OF REVIEW Here we focus on the application of probes for intracellular DUBs, a group of specific proteases involved in the ubiquitin proteasome system. In particular, the functional characterization of the active subunits of this family of proteases that specifically recognize ubiquitin and ubiquitin-like proteins will be discussed. In addition we present the potential and design of activity-based probes targeting kinases and phosphatases to study phosphorylation. MAJOR CONCLUSIONS Synthetic molecular probes have increased our understanding of the functional role of DUBs in living cells. In addition to the detection of enzymatic activities of known members, activity-based probes have contributed to a number of functional assignments of previously uncharacterized enzymes. This method enables cellular validation of the specificity of small molecule DUB inhibitors. GENERAL SIGNIFICANCE Molecular probes combined with mass spectrometry-based proteomics and cellular assays represent a powerful approach for discovery and functional validation, a concept that can be expanded to other enzyme classes. This addresses a need for more informative cell-based assays that are required to accelerate the drug development process. This article is part of a Special Issue entitled: Ubiquitin Drug Discovery and Diagnostics.
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Key Words
- abp, activity-based probe
- adp, adenosine diphosphate
- atp, adenosine triphosphate
- dub, deubiquitylating enzyme
- e1, ubiquitin activating enzyme
- e2, ubiquitin conjugating enzyme
- e3, ubiquitin-protein ligase
- haubbr2, ha-tagged ubiquitin ethyl bromide
- haubvme, ha-tagged ubiquitin vinyl methyl ester
- haubvs, ha-tagged ubiquitin vinyl sulfone
- ip, immunoprecipitation
- ms, mass spectrometry
- ptm, post-translational modification
- ptp, protein tyrosine phosphatase
- sds-page, sodium dodecylsulfate polyacrylamide gel electrophoresis
- spps, solid phase peptide synthesis
- ub, ubiquitin
- ubl, ubiquitin-like protein
- uch-l1, ubiquitin carboxyl terminal hydrolase isozyme l1
- uch-l3, ubiquitin carboxyl terminal hydrolase isozyme l3
- uch-l5, ubiquitin carboxyl terminal hydrolase isozyme l5
- usp7, ubiquitin specific processing protease 7
- ubiquitin
- small molecular inhibitor
- deubiquitinating enzyme
- ubiquitin specific protease
- proteomics
- active site-directed molecular probe
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Affiliation(s)
- Holger B Kramer
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford OX1 3QX, UK
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178
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Kalim KW, Basler M, Kirk CJ, Groettrup M. Immunoproteasome subunit LMP7 deficiency and inhibition suppresses Th1 and Th17 but enhances regulatory T cell differentiation. THE JOURNAL OF IMMUNOLOGY 2012; 189:4182-93. [PMID: 22984077 DOI: 10.4049/jimmunol.1201183] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The immunoproteasome generates peptides presented on MHC class I molecules to cytotoxic T cells. ONX 0914 (formerly called PR-957) is a selective inhibitor of the immunoproteasome subunit low molecular mass polypeptide (LMP) 7 (β5i) that attenuates disease progression in mouse models of diabetes, colitis, and arthritis. The aim of this study was to investigate the effect of LMP7-specific inhibition on major Th cell differentiation pathways involved in the progression of autoimmune diseases in vitro and in vivo. We used ONX 0914-treated wild-type CD4(+) T cells and also LMP7(-/-) CD4(+) T cells under different Th cell-polarizing conditions, focusing on the effector cytokines and transcription factors involved, and compared them with wild-type CD4(+) T cells. Mouse models of dextran sodium sulfate-induced colitis and a T cell transfer model of colitis were used for in vivo assessment. Deletion or inhibition of LMP7 suppressed generation of Th17 but promoted regulatory T cell (Treg) development. In developing Th17 cells, immunoproteasome inhibition blocked phosphorylation of STAT3, whereas in Tregs, SMAD phosphorylation was enhanced. Additionally, LMP7 inhibition led to reduced STAT1 phosphorylation and Th1 differentiation. These findings were confirmed in vivo as LMP7 inhibition or deficiency resulted in reduced Th1 and Th17 expansion while promoting Treg development in dextran sodium sulfate-induced colitis. Also, in a T cell-dependent transfer model of colitis, LMP7-specific inhibition led to reduced Th1 and Th17 differentiation in vivo. LMP7 governs Th cell lineage determination by affecting the balance of receptor proximal signals during differentiation. These data render LMP7 a promising drug target for the treatment of autoimmune diseases.
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Affiliation(s)
- Khalid W Kalim
- Division of Immunology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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179
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180
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Joeris T, Schmidt N, Ermert D, Krienke P, Visekruna A, Kuckelkorn U, Kaufmann SHE, Steinhoff U. The proteasome system in infection: impact of β5 and LMP7 on composition, maturation and quantity of active proteasome complexes. PLoS One 2012; 7:e39827. [PMID: 22768135 PMCID: PMC3387237 DOI: 10.1371/journal.pone.0039827] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Accepted: 05/27/2012] [Indexed: 12/21/2022] Open
Abstract
Proteasomes are the major enzyme complexes for non-lysosomal protein degradation in eukaryotic cells. Mammals express two sets of catalytic subunits: the constitutive subunits β1, β2 and β5 and the immunosubunits LMP2 (β1i), MECL-1 (β2i) and LMP7 (β5i). The LMP7-propeptide (proLMP7) is required for optimal maturation of LMP2/MECL-1-containing precursors to mature immunoproteasomes, but can also mediate efficient integration into mixed proteasomes containing β1 and β2. In contrast, the β5-propeptide (proβ5) has been suggested to promote preferential integration into β1/β2-containing precursors, consequently favouring the formation of constitutive proteasomes. Here, we show that proβ5 predominantly promotes integration into LMP2/MECL-1-containing precursors in IFNγ-stimulated, LMP7-deficient cells and infected LMP7-deficient mice. This demonstrates that proβ5 does not direct preferential integration into β1/β2-containing precursors, but instead promotes the formation of mixed LMP2/MECL-1/β5 proteasomes under inflammatory conditions. Moreover, the propeptides substantially differ in their capacity to promote proteasome maturation, with proLMP7 showing a significantly higher chaperone activity as compared to proβ5. Increased efficiency of proteasome maturation mediated by proLMP7 is required for optimal MHC class I cell surface expression and is equally important as the catalytic activity of immunoproteasomes. Intriguingly, induction of LMP7 by infection not only results in rapid exchange of constitutive by immunosubunits, as previously suggested, but also increases the total proteasome abundance within the infected tissue. Hence our data identify a novel LMP7-dependend mechanism to enhance the activity of the proteasome system in infection, which is based on the high chaperone activity of proLMP7 and relies on accelerated maturation of active proteasome complexes.
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Affiliation(s)
- Thorsten Joeris
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Nicole Schmidt
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - David Ermert
- Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Petra Krienke
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Alexander Visekruna
- Institute for Microbiology and Hygiene, Philipps University Marburg, Hessen, Marburg, Germany
| | | | - Stefan H. E. Kaufmann
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Ulrich Steinhoff
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
- Institute for Microbiology and Hygiene, Philipps University Marburg, Hessen, Marburg, Germany
- * E-mail:
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181
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Huber EM, Groll M. Inhibitors for the immuno- and constitutive proteasome: current and future trends in drug development. Angew Chem Int Ed Engl 2012; 51:8708-20. [PMID: 22711561 DOI: 10.1002/anie.201201616] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Indexed: 01/30/2023]
Abstract
Proteolytic degradation is an essential cellular process which is primarily carried out by the 20S proteasome core particle (CP), a protease of 720 kDa and 28 individual subunits. As a result of its central functional role, the proteasome represents an attractive drug target that has been extensively investigated during the last decade and validated by the approval of bortezomib by the US Food and Drug Administration (FDA). Currently, several optimized second-generation proteasome inhibitors are being explored as anticancer drugs in clinical trials, and most of them target both constitutive proteasomes (cCPs) and immunoproteasomes (iCPs). However, selective inhibition of the iCPs, a distinct class of proteasomes predominantly expressed in immune cells, appears to be a promising therapeutic rationale for the treatment of autoimmune disorders. Although a few selective agents have already been identified, the recently determined crystal structure of the iCP will further promote the development and optimization of iCP-selective compounds.
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Affiliation(s)
- Eva Maria Huber
- Center for Integrated Protein Science at the Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
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182
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Huber EM, Groll M. Inhibitoren für das konstitutive Proteasom und das Immunoproteasom: aktuelle und zukünftige Tendenzen in der Medikamentenentwicklung. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201616] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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183
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Lansdell TA, Hewlett NM, Skoumbourdis AP, Fodor MD, Seiple IB, Su S, Baran PS, Feldman KS, Tepe JJ. Palau'amine and related oroidin alkaloids dibromophakellin and dibromophakellstatin inhibit the human 20S proteasome. JOURNAL OF NATURAL PRODUCTS 2012; 75:980-985. [PMID: 22591513 PMCID: PMC3367325 DOI: 10.1021/np300231f] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report herein that the oroidin-derived alkaloids palau'amine (1), dibromophakellin (2), and dibromophakellstatin (3) inhibit the proteolytic activity of the human 20S proteasome as well as the (i)20S immunoproteasome catalytic core. Palau'amine is found to prevent the degradation of ubiquitinylated proteins, including IκBα, in cell culture, which may be indicative of the potential mechanism by which these agents exhibit their exciting cytotoxic and immunosuppressive properties.
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Affiliation(s)
- Theresa A. Lansdell
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48823
| | - Nicole M. Hewlett
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48823
| | | | - Matthew D. Fodor
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Ian B. Seiple
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Shun Su
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Phil. S. Baran
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Ken S. Feldman
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Jetze J. Tepe
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48823
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184
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Huber EM, Basler M, Schwab R, Heinemeyer W, Kirk CJ, Groettrup M, Groll M. Immuno- and constitutive proteasome crystal structures reveal differences in substrate and inhibitor specificity. Cell 2012; 148:727-38. [PMID: 22341445 DOI: 10.1016/j.cell.2011.12.030] [Citation(s) in RCA: 385] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/17/2011] [Accepted: 12/02/2011] [Indexed: 01/19/2023]
Abstract
Constitutive proteasomes and immunoproteasomes shape the peptide repertoire presented by major histocompatibility complex class I (MHC-I) molecules by harboring different sets of catalytically active subunits. Here, we present the crystal structures of constitutive proteasomes and immunoproteasomes from mouse in the presence and absence of the epoxyketone inhibitor PR-957 (ONX 0914) at 2.9 Å resolution. Based on our X-ray data, we propose a unique catalytic feature for the immunoproteasome subunit β5i/LMP7. Comparison of ligand-free and ligand-bound proteasomes reveals conformational changes in the S1 pocket of β5c/X but not β5i, thereby explaining the selectivity of PR-957 for β5i. Time-resolved structures of yeast proteasome:PR-957 complexes indicate that ligand docking to the active site occurs only via the reactive head group and the P1 side chain. Together, our results support structure-guided design of inhibitory lead structures selective for immunoproteasomes that are linked to cytokine production and diseases like cancer and autoimmune disorders.
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Affiliation(s)
- Eva M Huber
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Garching D-85747, Germany
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185
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Structural features and binding free energies for non-covalent inhibitors interacting with immunoproteasome by molecular modeling and dynamics simulations. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1203-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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186
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Dennissen FJA, Kholod N, van Leeuwen FW. The ubiquitin proteasome system in neurodegenerative diseases: culprit, accomplice or victim? Prog Neurobiol 2012; 96:190-207. [PMID: 22270043 DOI: 10.1016/j.pneurobio.2012.01.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/18/2011] [Accepted: 01/05/2012] [Indexed: 12/14/2022]
Abstract
A shared hallmark for many neurodegenerative disorders is the accumulation of toxic protein species which is assumed to be the cause for these diseases. Since the ubiquitin proteasome system (UPS) is the most important pathway for selective protein degradation it is likely that it is involved in the aetiology neurodegenerative disorders. Indeed, impairment of the UPS has been reported to occur during neurodegeneration. Although accumulation of toxic protein species (amyloid β) are in turn known to impair the UPS the relationship is not necessarily causal. We provide an overview of the most recent insights in the roles the UPS plays in protein degradation and other processes. Additionally, we discuss the role of the UPS in clearance of the toxic proteins known to accumulate in the hallmarks of neurodegenerative diseases. The present paper will focus on critically reviewing the involvement of the UPS in specific neurodegenerative diseases and will discuss if UPS impairment is a cause, a consequence or both of the disease.
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Affiliation(s)
- F J A Dennissen
- Department of Neuroscience, Faculty of Health Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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187
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Carmony KC, Lee DM, Wu Y, Lee NR, Wehenkel M, Lee J, Lei B, Zhan CG, Kim KB. A bright approach to the immunoproteasome: development of LMP2/β1i-specific imaging probes. Bioorg Med Chem 2012; 20:607-13. [PMID: 21741845 PMCID: PMC3193892 DOI: 10.1016/j.bmc.2011.06.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 05/31/2011] [Accepted: 06/14/2011] [Indexed: 01/01/2023]
Abstract
While the constitutive, 26S proteasome plays an important role in regulating many important cellular processes, a variant form known as the immunoproteasome is thought to primarily function in adaptive immune responses. However, recent studies indicate an association of immunoproteasomes with many physiological disorders such as cancer, neurodegenerative, and inflammatory diseases. Despite this, the detailed functions of the immunoproteasome remain poorly understood. Immunoproteasome-specific probes are essential to gain insight into immunoproteasome function. Here, we describe for the first time the development of cell-permeable activity-based fluorescent probes, UK101-Fluor and UK101-B660, which selectively target the catalytically active LMP2/β1i subunit of the immunoproteasome. These probes facilitate rapid detection of the cellular localization of catalytically active immunoproteasomes in living cells, providing a valuable tool to analyze immunoproteasome functions. Additionally, as LMP2/β1i may serve as a potential tumor biomarker, an LMP2/β1i-targeting fluorescent imaging probe may be applicable to a rapid readout assay to determine tumor LMP2/β1i levels.
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Affiliation(s)
- Kimberly Cornish Carmony
- Department of Pharmaceutical Science, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
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188
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de Wilt LHAM, Jansen G, Assaraf YG, van Meerloo J, Cloos J, Schimmer AD, Chan ET, Kirk CJ, Peters GJ, Kruyt FAE. Proteasome-based mechanisms of intrinsic and acquired bortezomib resistance in non-small cell lung cancer. Biochem Pharmacol 2012; 83:207-217. [PMID: 22027222 DOI: 10.1016/j.bcp.2011.10.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/07/2011] [Accepted: 10/11/2011] [Indexed: 01/17/2023]
Abstract
The proteasome inhibitor bortezomib, registered for Multiple Myeloma treatment, is currently explored for activity in solid tumors including non-small cell lung cancer (NSCLC). Here we studied the proteasome-based mechanisms underlying intrinsic and acquired bortezomib resistance in NSCLC cells. Various NSCLC cell lines displayed differential intrinsic sensitivities to bortezomib. High basal chymotrypsin- and caspase-like proteasome activities correlated with bortezomib resistance in these cells. Next, via stepwise selection, acquired bortezomib resistant cells were obtained with 8-70-fold increased resistance. Cross-resistance was found to proteasome inhibitors specifically targeting β-subunits, but not to the novel α-subunit-specific proteasome inhibitor (5AHQ). Consistently, bortezomib-resistant cells required higher bortezomib concentrations to induce G2/M arrest and apoptosis. Interestingly, bortezomib concentration-dependent caspase cleavage, Mcl-1 and NOXA accumulation remained intact in resistant H460 and SW1573 cells, while A549 resistant cells displayed different expression profiles suggesting additional and more protein specific adaptations. Furthermore, bortezomib-resistant cells exhibited increased levels of both constitutive and immuno-β-subunits. Sequence analysis of the bortezomib-binding pocket in the β5-subunit revealed Ala49Thr, Met45Val and Cys52Phe substitutions that were not previously described in solid tumors. Bortezomib-resistant cells displayed reduced catalytic proteasome activities and required higher bortezomib concentrations to achieve comparable inhibition of proteasome activity. Taken together, these findings establish that high basal levels of proteasome activity correlate with intrinsic bortezomib resistance. Furthermore, acquired bortezomib resistance in NSCLC is associated with proteasome subunit overexpression and emergence of mutant β5-subunits that likely compromise bortezomib binding. α-Subunit-specific proteasome inhibitors, however, can efficiently bypass this resistance modality.
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Affiliation(s)
- Leonie H A M de Wilt
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands
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189
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Sutoh Y, Kondo M, Ohta Y, Ota T, Tomaru U, Flajnik MF, Kasahara M. Comparative genomic analysis of the proteasome β5t subunit gene: implications for the origin and evolution of thymoproteasomes. Immunogenetics 2012; 64:49-58. [PMID: 21748441 PMCID: PMC3805029 DOI: 10.1007/s00251-011-0558-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 06/27/2011] [Indexed: 12/22/2022]
Abstract
The thymoproteasome is a recently discovered, specialized form of 20S proteasomes expressed exclusively in the thymic cortex. Although the precise molecular mechanism by which the thymoproteasome exerts its function remains to be elucidated, accumulating evidence indicates that it plays a crucial role in positive selection of T cells. In the present study, we analyzed the evolution of the β5t subunit, a β-type catalytic subunit uniquely present in thymoproteasomes. The gene coding for the β5t subunit, designated PSMB11, was identified in the cartilaginous fish, the most divergent group of jawed vertebrates compared to the other jawed vertebrates, but not in jawless vertebrates or invertebrates. Interestingly, teleost fish have two copies of apparently functional PSMB11 genes, designated PSMB11a and PSMB11b, that encode β5t subunits with distinct amino acids in the S1 pocket. BLAST searches of genome databases suggest that birds such as chickens, turkey, and zebra finch lost the PSMB11 gene, and have neither thymoproteasomes nor immunoproteasomes. In mammals, reptiles, amphibians, and teleost fishes, the PSMB11 gene (the PSMB11a gene in teleost fish) is located next to the PSMB5 gene coding for the β5 subunit of the standard 20S proteasome, indicating that the PSMB11 gene arose by tandem duplication from the evolutionarily more ancient PSMB5 gene. The general absence of introns in PSMB11 and an unusual exon-intron structure of jawed vertebrate PSMB5 suggest that PSMB5 lost introns and duplicated in tandem in a common ancestor of jawed vertebrates, with PSMB5 subsequently gaining two introns and PSMB11 remaining intronless.
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Affiliation(s)
- Yoichi Sutoh
- Department of Pathology, Hokkaido University Graduate School of Medicine, North-15 West-7, Sapporo 060-8638, Japan
| | - Mizuho Kondo
- Department of Pathology, Hokkaido University Graduate School of Medicine, North-15 West-7, Sapporo 060-8638, Japan
| | - Yuko Ohta
- Department of Microbiology and Immunology, University of Maryland, 685 West Baltimore Street, Baltimore, MD 21201, USA
| | - Tatsuya Ota
- Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies, Hayama 240-0193, Japan
| | - Utano Tomaru
- Department of Pathology, Hokkaido University Graduate School of Medicine, North-15 West-7, Sapporo 060-8638, Japan
| | - Martin F. Flajnik
- Department of Microbiology and Immunology, University of Maryland, 685 West Baltimore Street, Baltimore, MD 21201, USA
| | - Masanori Kasahara
- Department of Pathology, Hokkaido University Graduate School of Medicine, North-15 West-7, Sapporo 060-8638, Japan,
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190
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Powell SR, Herrmann J, Lerman A, Patterson C, Wang X. The ubiquitin-proteasome system and cardiovascular disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 109:295-346. [PMID: 22727426 DOI: 10.1016/b978-0-12-397863-9.00009-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over the past decade, the role of the ubiquitin-proteasome system (UPS) has been the subject of numerous studies to elucidate its role in cardiovascular physiology and pathophysiology. There have been many advances in this field including the use of proteomics to achieve a better understanding of how the cardiac proteasome is regulated. Moreover, improved methods for the assessment of UPS function and the development of genetic models to study the role of the UPS have led to the realization that often the function of this system deviates from the norm in many cardiovascular pathologies. Hence, dysfunction has been described in atherosclerosis, familial cardiac proteinopathies, idiopathic dilated cardiomyopathies, and myocardial ischemia. This has led to numerous studies of the ubiquitin protein (E3) ligases and their roles in cardiac physiology and pathophysiology. This has also led to the controversial proposition of treating atherosclerosis, cardiac hypertrophy, and myocardial ischemia with proteasome inhibitors. Furthering our knowledge of this system may help in the development of new UPS-based therapeutic modalities for mitigation of cardiovascular disease.
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Affiliation(s)
- Saul R Powell
- Center for Heart and Lung Research, The Feinstein Institute for Medical Research, Manhasset, New York, USA
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191
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Berhane S, Aresté C, Ablack JN, Ryan GB, Blackbourn DJ, Mymryk JS, Turnell AS, Steele JC, Grand RJA. Adenovirus E1A interacts directly with, and regulates the level of expression of, the immunoproteasome component MECL1. Virology 2011; 421:149-58. [PMID: 22018786 DOI: 10.1016/j.virol.2011.09.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 07/29/2011] [Accepted: 09/27/2011] [Indexed: 10/16/2022]
Abstract
Proteasomes represent the major non-lysosomal mechanism responsible for the degradation of proteins. Following interferon γ treatment 3 proteasome subunits are replaced producing immunoproteasomes. Adenovirus E1A interacts with components of the 20S and 26S proteasome and can affect presentation of peptides. In light of these observations we investigated the relationship of AdE1A to the immunoproteasome. AdE1A interacts with the immunoproteasome subunit, MECL1. In contrast, AdE1A binds poorly to the proteasome β2 subunit which is replaced by MECL1 in the conversion of proteasomes to immunoproteasomes. Binding sites on E1A for MECL1 correspond to the N-terminal region and conserved region 3. Furthermore, AdE1A causes down-regulation of MECL1 expression, as well as LMP2 and LMP7, induced by interferon γ treatment during Ad infections or following transient transfection. Consistent with previous reports AdE1A reduced IFNγ-stimulated STAT1 phosphorylation which appeared to be responsible for its ability to reduce expression of immunoproteasome subunits.
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Affiliation(s)
- Sarah Berhane
- Cancer Research UK, School of Cancer Sciences, University of Birmingham, Birmingham B15 2TT, UK
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192
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García-Medel N, Sanz-Bravo A, Barnea E, Admon A, López de Castro JA. The origin of proteasome-inhibitor resistant HLA class I peptidomes: a study with HLA-A*68:01. Mol Cell Proteomics 2011; 11:M111.011486. [PMID: 21969608 DOI: 10.1074/mcp.m111.011486] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Some HLA class I molecules bind a significant fraction of their constitutive peptidomes in the presence of proteasome inhibitors. In this study, A*68:01-bound peptides, and their parental proteins, were characterized through massive mass spectrometry sequencing to refine its binding motif, including the nearly exclusive preference for C-terminal basic residues. Stable isotope tagging was used to distinguish proteasome-inhibitor sensitive and resistant ligands. The latter accounted for less than 20% of the peptidome and, like in HLA-B27, arose predominantly from small and basic proteins. Under the conditions used for proteasome inhibition in vivo, epoxomicin and MG-132 incompletely inhibited the hydrolysis of fluorogenic substrates specific for the tryptic or for both the tryptic and chymotryptic subspecificities, respectively. This incomplete inhibition was also reflected in the cleavage of synthetic peptide precursors of A*68:01 ligands. For these substrates, the inhibition of the proteasome resulted in altered cleavage patterns. However these alterations did not upset the balance between cleavage at peptide bonds resulting in epitope destruction and those leading to their generation. The results indicate that inhibitor-resistant HLA class I ligands are not necessarily produced by non-proteasomal pathways. However, their generation is not simply explained by decreased epitope destruction upon incomplete proteasomal inhibition and may require additional proteolytic steps acting on incompletely processed proteasomal products.
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Affiliation(s)
- Noel García-Medel
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/ Nicolas Cabrera N.1, Universidad Autónoma, 28049 Madrid, Spain
| | - Alejandro Sanz-Bravo
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/ Nicolas Cabrera N.1, Universidad Autónoma, 28049 Madrid, Spain
| | - Eilon Barnea
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Arie Admon
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - José A López de Castro
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/ Nicolas Cabrera N.1, Universidad Autónoma, 28049 Madrid, Spain.
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193
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Kitamura A, Maekawa Y, Uehara H, Izumi K, Kawachi I, Nishizawa M, Toyoshima Y, Takahashi H, Standley DM, Tanaka K, Hamazaki J, Murata S, Obara K, Toyoshima I, Yasutomo K. A mutation in the immunoproteasome subunit PSMB8 causes autoinflammation and lipodystrophy in humans. J Clin Invest 2011; 121:4150-60. [PMID: 21881205 DOI: 10.1172/jci58414] [Citation(s) in RCA: 226] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 07/27/2011] [Indexed: 11/17/2022] Open
Abstract
Proteasomes are multisubunit proteases that play a critical role in maintaining cellular function through the selective degradation of ubiquitinated proteins. When 3 additional β subunits, expression of which is induced by IFN-γ, are substituted for their constitutively expressed counterparts, the structure is converted to an immunoproteasome. However, the underlying roles of immunoproteasomes in human diseases are poorly understood. Using exome analysis, we found a homozygous missense mutation (G197V) in immunoproteasome subunit, β type 8 (PSMB8), which encodes one of the β subunits induced by IFN-γ in patients from 2 consanguineous families. Patients bearing this mutation suffered from autoinflammatory responses that included recurrent fever and nodular erythema together with lipodystrophy. This mutation increased assembly intermediates of immunoproteasomes, resulting in decreased proteasome function and ubiquitin-coupled protein accumulation in the patient's tissues. In the patient's skin and B cells, IL-6 was highly expressed, and there was reduced expression of PSMB8. Downregulation of PSMB8 inhibited the differentiation of murine and human adipocytes in vitro, and injection of siRNA against Psmb8 in mouse skin reduced adipocyte tissue volume. These findings identify PSMB8 as an essential component and regulator not only of inflammation, but also of adipocyte differentiation, and indicate that immunoproteasomes have pleiotropic functions in maintaining the homeostasis of a variety of cell types.
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Affiliation(s)
- Akiko Kitamura
- Department of Immunology and Parasitology, Institute of Health Biosciences,University of Tokushima Graduate School, Tokushima, Japan
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194
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Opitz E, Koch A, Klingel K, Schmidt F, Prokop S, Rahnefeld A, Sauter M, Heppner FL, Völker U, Kandolf R, Kuckelkorn U, Stangl K, Krüger E, Kloetzel PM, Voigt A. Impairment of immunoproteasome function by β5i/LMP7 subunit deficiency results in severe enterovirus myocarditis. PLoS Pathog 2011; 7:e1002233. [PMID: 21909276 PMCID: PMC3164653 DOI: 10.1371/journal.ppat.1002233] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 07/07/2011] [Indexed: 12/18/2022] Open
Abstract
Proteasomes recognize and degrade poly-ubiquitinylated proteins. In infectious disease, cells activated by interferons (IFNs) express three unique catalytic subunits β1i/LMP2, β2i/MECL-1 and β5i/LMP7 forming an alternative proteasome isoform, the immunoproteasome (IP). The in vivo function of IPs in pathogen-induced inflammation is still a matter of controversy. IPs were mainly associated with MHC class I antigen processing. However, recent findings pointed to a more general function of IPs in response to cytokine stress. Here, we report on the role of IPs in acute coxsackievirus B3 (CVB3) myocarditis reflecting one of the most common viral disease entities among young people. Despite identical viral load in both control and IP-deficient mice, IP-deficiency was associated with severe acute heart muscle injury reflected by large foci of inflammatory lesions and severe myocardial tissue damage. Exacerbation of acute heart muscle injury in this host was ascribed to disequilibrium in protein homeostasis in viral heart disease as indicated by the detection of increased proteotoxic stress in cytokine-challenged cardiomyocytes and inflammatory cells from IP-deficient mice. In fact, due to IP-dependent removal of poly-ubiquitinylated protein aggregates in the injured myocardium IPs protected CVB3-challenged mice from oxidant-protein damage. Impaired NFκB activation in IP-deficient cardiomyocytes and inflammatory cells and proteotoxic stress in combination with severe inflammation in CVB3-challenged hearts from IP-deficient mice potentiated apoptotic cell death in this host, thus exacerbating acute tissue damage. Adoptive T cell transfer studies in IP-deficient mice are in agreement with data pointing towards an effective CD8 T cell immune. This study therefore demonstrates that IP formation primarily protects the target organ of CVB3 infection from excessive inflammatory tissue damage in a virus-induced proinflammatory cytokine milieu.
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Affiliation(s)
- Elisa Opitz
- Medizinische Klinik für Kardiologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Annett Koch
- Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Karin Klingel
- Abteilung Molekulare Pathologie, Institut für Pathologie und Neuropathologie, Eberhard-Karls-Universität, Tuebingen, Germany
| | - Frank Schmidt
- Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität, Greifswald, Germany
| | - Stefan Prokop
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Anna Rahnefeld
- Medizinische Klinik für Kardiologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Martina Sauter
- Abteilung Molekulare Pathologie, Institut für Pathologie und Neuropathologie, Eberhard-Karls-Universität, Tuebingen, Germany
| | - Frank L. Heppner
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Uwe Völker
- Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität, Greifswald, Germany
| | - Reinhard Kandolf
- Abteilung Molekulare Pathologie, Institut für Pathologie und Neuropathologie, Eberhard-Karls-Universität, Tuebingen, Germany
| | - Ulrike Kuckelkorn
- Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Karl Stangl
- Medizinische Klinik für Kardiologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Elke Krüger
- Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Peter M. Kloetzel
- Institut für Biochemie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Antje Voigt
- Medizinische Klinik für Kardiologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
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195
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Zakharova LA, Khegai II, Sharova NP, Melnikova VI, Karpova YD, Astakhova TM, Popova NA, Ivanova LN. Pattern of MHC class I and immune proteasome expression in Walker 256 tumor during growth and regression in Brattleboro rats with the hereditary defect of arginine-vasopressin synthesis. Cell Immunol 2011; 271:385-91. [PMID: 21889127 DOI: 10.1016/j.cellimm.2011.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 06/23/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022]
Abstract
Dynamics of the expression of MHC class I, immune proteasomes and proteasome regulators 19S, PA28, total proteasome pool and proteasome chymotrypsin-like activity in Walker 256 tumor after implantation into Brattleboro rats with the hereditary defect of arginine-vasopressin synthesis was studied. The tumor growth and regression in Brattleboro rats were accompanied by changes in the proteasome subunit level unlike the tumor growth in WAG rats with normal expression of arginine-vasopressin gene. In the tumor implanted into Brattleboro rats the immune proteasome level was maximal between days 14 and 17, when the tumor underwent regression. Conversely, the expression of proteasome regulators tended to decrease during this period. Immune proteasomes are known to produce antigen epitopes for MHC class I to be presented to CD8+ T lymphocytes. Enhanced expression of immune proteasomes coincided with the recovery of MHC class I expression, suggesting the efficient presentation of tumor antigens in Brattleboro rats.
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Affiliation(s)
- Liudmila A Zakharova
- NK Koltsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
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196
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Abstract
AbstractSearching the antitumor drug targets among proteasomes, “ubiquitous” enzyme systems, may provide a new impulse to the antitumor drug discovery. In this study, changes in the proteasome pool in the development of human papillary thyroid carcinoma were determined. Proteasome activities were evaluated by hydrolysis of commercial fluorogenic peptides. Changes in the expression of the total proteasome pool, proteasome 19S activator and proteolytic constitutive subunits X(β5), Y(β1) and immune subunits LMP7 (β5i) and LMP2 (β1i) were investigated by Western blotting. The distribution of the proteasome subunits in thyroid gland cells was detected by immunohistochemistry. It was shown that the chymotrypsin- and caspase-like activities as well as the expression of the total proteasome pool, proteasome 19S activator and immune subunits increased gradually in the tumors at the T2N0M0 and T3N0M0 stages in comparison with the control tissues. Among the structures studied, the expression of the 19S activator and immune proteasomes, which contain the LMP2 (β1i) subunit, was enhanced to the largest degree in tumor cells. The data obtained may be implicated in a new therapeutic strategy. Taking into consideration the antitumor function of the immune proteasomes, we advance the 19S activator as the target for the development of a novel antitumor therapy.
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197
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Liu J, Zhang H, Xiao Z, Wang F, Wang X, Wang Y. Combined 3D-QSAR, molecular docking and molecular dynamics study on derivatives of peptide epoxyketone and tyropeptin-boronic acid as inhibitors against the β5 subunit of human 20S proteasome. Int J Mol Sci 2011; 12:1807-35. [PMID: 21673924 PMCID: PMC3111635 DOI: 10.3390/ijms12031807] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 02/14/2011] [Accepted: 02/28/2011] [Indexed: 12/13/2022] Open
Abstract
An abnormal ubiquitin-proteasome is found in many human diseases, especially in cancer, and has received extensive attention as a promising therapeutic target in recent years. In this work, several in silico models have been built with two classes of proteasome inhibitors (PIs) by using 3D-QSAR, homology modeling, molecular docking and molecular dynamics (MD) simulations. The study resulted in two types of satisfactory 3D-QSAR models, i.e., the CoMFA model (Q(2) = 0.462, R(2) (pred) = 0.820) for epoxyketone inhibitors (EPK) and the CoMSIA model (Q(2) = 0.622, R(2) (pred) = 0.821) for tyropeptin-boronic acid derivatives (TBA). From the contour maps, some key structural factors responsible for the activity of these two series of PIs are revealed. For EPK inhibitors, the N-cap part should have higher electropositivity; a large substituent such as a benzene ring is favored at the C6-position. In terms of TBA inhibitors, hydrophobic substituents with a larger size anisole group are preferential at the C8-position; higher electropositive substituents like a naphthalene group at the C3-position can enhance the activity of the drug by providing hydrogen bond interaction with the protein target. Molecular docking disclosed that residues Thr60, Thr80, Gly106 and Ser189 play a pivotal role in maintaining the drug-target interactions, which are consistent with the contour maps. MD simulations further indicated that the binding modes of each conformation derived from docking is stable and in accord with the corresponding structure extracted from MD simulation overall. These results can offer useful theoretical references for designing more potent PIs.
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Affiliation(s)
- Jianling Liu
- College of Life Sciences, Northwest University, Xi’an, Shaanxi 710069, China
| | - Hong Zhang
- College of Life Sciences, Northwest University, Xi’an, Shaanxi 710069, China
| | - Zhengtao Xiao
- Center of Bioinformatics, Northwest A&F University, Yangling, Shaanxi 712100, China; E-Mail:
| | - Fangfang Wang
- College of Life Sciences, Northwest University, Xi’an, Shaanxi 710069, China
| | - Xia Wang
- School of Chemical Engineering, Dalian University of Technology, Dalian 116012, China
| | - Yonghua Wang
- Center of Bioinformatics, Northwest A&F University, Yangling, Shaanxi 712100, China; E-Mail:
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198
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de Graaf N, van Helden MJG, Textoris-Taube K, Chiba T, Topham DJ, Kloetzel PM, Zaiss DMW, Sijts AJAM. PA28 and the proteasome immunosubunits play a central and independent role in the production of MHC class I-binding peptides in vivo. Eur J Immunol 2011; 41:926-35. [PMID: 21360704 DOI: 10.1002/eji.201041040] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 12/02/2010] [Accepted: 01/05/2011] [Indexed: 11/08/2022]
Abstract
Proteasomes play a fundamental role in the processing of intracellular antigens into peptides that bind to MHC class I molecules for the presentation of CD8(+) T cells. Three IFN-γ-inducible catalytic proteasome (immuno)subunits as well as the IFN-γ-inducible proteasome activator PA28 dramatically accelerate the generation of a subset of MHC class I-presented antigenic peptides. To determine whether these IFN-γ-inducible proteasome components play a compounded role in antigen processing, we generated mice lacking both PA28 and immunosubunits β5i/LMP7 and β2i/MECL-1. Analyses of MHC class I cell-surface levels ex vivo demonstrated that PA28 deficiency reduced the production of MHC class I-binding peptides both in cells with and without immunosubunits, in the latter cells further decreasing an already diminished production of MHC ligands in the absence of immunoproteasomes. In contrast, the immunosubunits but not PA28 appeared to be of critical importance for the induction of CD8(+) T-cell responses to multiple dominant Influenza and Listeria-derived epitopes. Taken together, our data demonstrate that PA28 and the proteasome immunosubunits use fundamentally different mechanisms to enhance the supply of MHC class I-binding peptides; however, only the immunosubunit-imposed effects on proteolytic epitope processing appear to have substantial influence on the specificity of pathogen-specific CD8(+) T-cell responses.
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Affiliation(s)
- Natascha de Graaf
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands
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199
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Hutchinson S, Sims S, O'Hara G, Silk J, Gileadi U, Cerundolo V, Klenerman P. A dominant role for the immunoproteasome in CD8+ T cell responses to murine cytomegalovirus. PLoS One 2011; 6:e14646. [PMID: 21304910 PMCID: PMC3033404 DOI: 10.1371/journal.pone.0014646] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 01/06/2011] [Indexed: 01/08/2023] Open
Abstract
Murine cytomegalovirus (MCMV) is an important animal model of human cytomegalovirus (HCMV), a β-Herpesvirus that infects the majority of the world's population and causes disease in neonates and immunocompromised adults. CD8+ T cells are a major part of the immune response to MCMV and HCMV. Processing of peptides for presentation to CD8+ T cells may be critically dependent on the immunoproteasome, expression of which is affected by MCMV. However, the overall importance of the immunoproteasome in the generation of immunodominant peptides from MCMV is not known. We therefore examined the role of the immunoproteasome in stimulation of CD8+ T cell responses to MCMV – both conventional memory responses and those undergoing long-term expansion or “inflation”. We infected LMP7−/− and C57BL/6 mice with MCMV or with newly-generated recombinant vaccinia viruses (rVVs) encoding the immunodominant MCMV protein M45 in either full-length or epitope-only minigene form. We analysed CD8+ T cell responses using intracellular cytokine stain (ICS) and MHC Class I tetramer staining for a panel of MCMV-derived epitopes. We showed a critical role for immunoproteasome in MCMV affecting all epitopes studied. Interestingly we found that memory “inflating” epitopes demonstrate reduced immunoproteasome dependence compared to non-inflating epitopes. M45-specific responses induced by rVVs remain immunoproteasome-dependent. These results help to define a critical restriction point for CD8+ T cell epitopes in natural cytomegalovirus (CMV) infection and potentially in vaccine strategies against this and other viruses.
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Affiliation(s)
- Sarah Hutchinson
- Nuffield Department of Clinical Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Stuart Sims
- Nuffield Department of Clinical Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Geraldine O'Hara
- Nuffield Department of Clinical Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Jon Silk
- Weatherall Institute of Molecular Medicine, Molecular Immunology Group, Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom
| | - Uzi Gileadi
- Weatherall Institute of Molecular Medicine, Molecular Immunology Group, Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom
| | - Vincenzo Cerundolo
- Weatherall Institute of Molecular Medicine, Molecular Immunology Group, Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom
| | - Paul Klenerman
- Nuffield Department of Clinical Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
- * E-mail:
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200
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Mel’nikova VI, Karpova YD, Afanasieva MA, Zakharova LA, Sharova NP. Immune proteasomes in the developing rat spleen. BIOL BULL+ 2011. [DOI: 10.1134/s1062359008020076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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