1
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Holly J, Yewdell JW. Game of Omes: ribosome profiling expands the MHC-I immunopeptidome. Curr Opin Immunol 2023; 83:102342. [PMID: 37247567 PMCID: PMC10524008 DOI: 10.1016/j.coi.2023.102342] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/31/2023]
Abstract
Peptide ligands presented by cell-surface MHC class-I molecules enable T cells to eradicate intracellular pathogens and cancers. The presented peptide repertoire, the class-I immunopeptidome, is generated from each cell's translatome in a highly biased manner to avoid overrepresenting highly abundant translation products. The immunopeptidome can only be defined by mass spectrometry (MS). Here, we review recent advances in immunopeptidomics, focusing on using ribosome profiling as the optimal MS database to optimize the false- and failed-discovery rates and relate these findings to the contribution of defective ribosomal products and cellular quality control mechanisms to MHC class-I antigen processing and presentation.
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Affiliation(s)
- Jaroslav Holly
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jonathan W Yewdell
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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2
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Vijayasimha K, Leestemaker-Palmer AL, Gibbs JS, Yewdell JW, Dolan BP. MLN4924 Inhibits Defective Ribosomal Product Antigen Presentation Independently of Direct NEDDylation of Protein Antigens. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:2273-2282. [PMID: 35428693 PMCID: PMC9288214 DOI: 10.4049/jimmunol.2100584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 03/01/2022] [Indexed: 05/17/2023]
Abstract
Successful direct MHC class I Ag presentation is dependent on the protein degradation machinery of the cell to generate antigenic peptides that can be loaded onto MHC class I molecules for surveillance by CD8+ T cells of the immune system. Most often this process involves the ubiquitin (Ub)-proteasome system; however, other Ub-like proteins have also been implicated in protein degradation and direct Ag presentation. In this article, we examine the role of neuronal precursor cell-expressed developmentally downregulated protein 8 (NEDD8) in direct Ag presentation in mouse cells. NEDD8 is the Ub-like protein with highest similarity to Ub, and fusion of NEDD8 to the N terminus of a target protein can lead to the degradation of target proteins. We find that appending NEDD8 to the N terminus of the model Ag OVA resulted in degradation by both the proteasome and the autophagy protein degradation pathways, but only proteasomal degradation, involving the proteasomal subunit NEDD8 ultimate buster 1, resulted in peptide presentation. When directly compared with Ub, NEDD8 fusion was less efficient at generating peptides. However, inactivation of the NEDD8-conugation machinery by treating cells with MLN4924 inhibited the presentation of peptides from the defective ribosomal product-derived form of a model Ag. These results demonstrate that NEDD8 activity in the cell is important for direct Ag presentation, but not by directly targeting proteins for degradation.
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Affiliation(s)
- Kartikeya Vijayasimha
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR; and
| | - Amy L Leestemaker-Palmer
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR; and
| | - James S Gibbs
- Laboratory of Viral Diseases, National Institutes of Allergy and Infectious Diseases, Bethesda, MD
| | - Jonathan W Yewdell
- Laboratory of Viral Diseases, National Institutes of Allergy and Infectious Diseases, Bethesda, MD
| | - Brian P Dolan
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR; and
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3
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Vijayasimha K, Tran MV, Leestemaker-Palmer AL, Dolan BP. Direct Conjugation of NEDD8 to the N-Terminus of a Model Protein Can Induce Degradation. Cells 2021; 10:854. [PMID: 33918652 PMCID: PMC8069691 DOI: 10.3390/cells10040854] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 12/28/2022] Open
Abstract
While the role of ubiquitin in protein degradation is well established, the role of other ubiquitin-like proteins (UBLs) in protein degradation is less clear. Neural precursor cell expressed developmentally down-regulated protein 8 (NEDD8) is the UBL with the highest level of amino acids identified when compared to ubiquitin. Here we tested if the N-terminal addition of NEDD8 to a protein of interest could lead to degradation. Mutation of critical glycine residues required for normal NEDD8 processing resulted in a non-cleavable fusion protein that was rapidly degraded within the cells by both the proteasome and autophagy. Both degradation pathways were dependent on a functional ubiquitin-conjugation system as treatment with MLN7243 increased levels of non-cleavable NEDD8-GFP. The degradation of non-cleavable, N-terminal NEDD8-GFP was not due to a failure of GFP folding as different NEDD8-GFP constructs with differing abilities to fold and fluoresce were similarly degraded. Though the fusion of NEDD8 to a protein resulted in degradation, treatment of cells with MLN4924, an inhibitor of the E1 activating enzyme for NEDD8, failed to prevent degradation of other destabilized substrates. Taken together these data suggest that under certain conditions, such as the model system described here, the covalent linkage of NEDD8 to a protein substrate may result in the target proteins degradation.
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Affiliation(s)
| | | | | | - Brian P. Dolan
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA; (K.V.); (M.V.T.); (A.L.L.-P.)
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4
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Nagamine BS, Godil J, Dolan BP. The Unfolded Protein Response Reveals eIF2α Phosphorylation as a Critical Factor for Direct MHC Class I Antigen Presentation. Immunohorizons 2021; 5:135-146. [PMID: 33685907 DOI: 10.4049/immunohorizons.2100012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 02/10/2021] [Indexed: 11/19/2022] Open
Abstract
The ability to modulate direct MHC class I (MHC I) Ag presentation is a desirable goal for the treatment of a variety of conditions, including autoimmune diseases, chronic viral infections, and cancers. It is therefore necessary to understand how changes in the cellular environment alter the cells' ability to present peptides to T cells. The unfolded protein response (UPR) is a signaling pathway activated by the presence of excess unfolded proteins in the endoplasmic reticulum. Previous studies have indicated that chemical induction of the UPR decreases direct MHC I Ag presentation, but the precise mechanisms are unknown. In this study, we used a variety of small molecule modulators of different UPR signaling pathways to query which UPR signaling pathways can alter Ag presentation in both murine and human cells. When signaling through the PERK pathway, and subsequent eIF2α phosphorylation, was blocked by treatment with GSK2656157, MHC I Ag presentation remain unchanged, whereas treatment with salubrinal, which has the opposite effect of GSK2656157, decreases both Ag presentation and overall cell-surface MHC I levels. Treatment with 4μ8C, an inhibitor of the IRE1α UPR activation pathway that blocks splicing of Xbp1 mRNA, also diminished MHC I Ag presentation. However, 4μ8C treatment unexpectedly led to an increase in eIF2α phosphorylation in addition to blocking IRE1α signaling. Given that salubrinal and 4μ8C lead to eIF2α phosphorylation and similar decreases in Ag presentation, we conclude that UPR signaling through PERK, leading to eIF2α phosphorylation, results in a modest decrease in direct MHC I Ag presentation.
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Affiliation(s)
- Brandy S Nagamine
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331
| | - Jamila Godil
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331
| | - Brian P Dolan
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331
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5
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A few good peptides: MHC class I-based cancer immunosurveillance and immunoevasion. Nat Rev Immunol 2020; 21:116-128. [PMID: 32820267 DOI: 10.1038/s41577-020-0390-6] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2020] [Indexed: 12/25/2022]
Abstract
The remarkable success of immune checkpoint inhibitors demonstrates the potential of tumour-specific CD8+ T cells to prevent and treat cancer. Although the number of lives saved by immunotherapy mounts, only a relatively small fraction of patients are cured. Here, we review two of the factors that limit the application of CD8+ T cell immunotherapies: difficulties in identifying tumour-specific peptides presented by MHC class I molecules and the ability of tumour cells to impair antigen presentation as they evolve under T cell selection. We describe recent advances in understanding how peptides are generated from non-canonical translation of defective ribosomal products, relate this to the dysregulated translation that is a feature of carcinogenesis and propose dysregulated translation as an important new source of tumour-specific peptides. We discuss how the synthesis and function of components of the antigen-processing and presentation pathway, including the recently described immunoribosome, are manipulated by tumours for immunoevasion and point to common druggable targets that may enhance immunotherapy.
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6
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George JA, Park SO, Choi JY, Uyangaa E, Eo SK. Double-faced implication of CD4 + Foxp3 + regulatory T cells expanded by acute dengue infection via TLR2/MyD88 pathway. Eur J Immunol 2020; 50:1000-1018. [PMID: 32125695 DOI: 10.1002/eji.201948420] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/29/2020] [Accepted: 02/27/2020] [Indexed: 01/03/2023]
Abstract
Dengue infection causes dengue fever (DF) and dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). CD4+ Foxp3+ Tregs are expanded in patients during dengue infection, and appear to be associated with clinical severity. However, molecular pathways involved in Treg proliferation and the reason for their insufficient control of severe diseases are poorly understood. Here, dengue infection induced the proliferation of functional CD4+ Foxp3+ Tregs via TLR2/MyD88 pathway. Surface TLR2 on Tregs was responsible for their proliferation, and dengue-expanded Tregs subverted in vivo differentiation of effector CD8+ T cells. An additional interesting finding was that dengue-infected hosts displayed changed levels of susceptibility to other diseases in TLR2-dependent manner. This change included enhanced susceptibility to tumors and bacterial infection, but highly enhanced resistance to viral infection. Further, the transfer of dengue-proliferated Tregs protected the recipients from dengue-induced DHF/DSS and LPS-induced sepsis. In contrast, dengue-infected hosts were more susceptible to sepsis, an effect attributable to early TLR2-dependent production of proinflammatory cytokines. These facts may explain the reason why in some patients, dengue-proliferated Tregs is insufficient to control DF and DHF/DSS. Also, our observations lead to new insights into Treg responses activated by dengue infection in a TLR2-dependent manner, which could differentially act on subsequent exposure to other disease-producing situations.
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Affiliation(s)
- Junu A George
- College of Veterinary Medicine and Bio-Safety Research Institute, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Seong Ok Park
- College of Veterinary Medicine and Bio-Safety Research Institute, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Jin Young Choi
- College of Veterinary Medicine and Bio-Safety Research Institute, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Erdenebelig Uyangaa
- College of Veterinary Medicine and Bio-Safety Research Institute, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Seong Kug Eo
- College of Veterinary Medicine and Bio-Safety Research Institute, Jeonbuk National University, Iksan, 54596, Republic of Korea
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7
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Yewdell JW, Dersh D, Fåhraeus R. Peptide Channeling: The Key to MHC Class I Immunosurveillance? Trends Cell Biol 2019; 29:929-939. [PMID: 31662235 DOI: 10.1016/j.tcb.2019.09.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 12/11/2022]
Abstract
MHC class I presentation of short peptides enables CD8+ T cell (TCD8+) immunosurveillance of tumors and intracellular pathogens. A key feature of the class I pathway is that the immunopeptidome is highly skewed from the cellular degradome, indicating high selectivity of the access of protease-generated peptides to class I molecules. Similarly, in professional antigen-presenting cells, peptides from minute amounts of proteins introduced into the cytosol outcompete an overwhelming supply of constitutively generated peptides. Here, we propose that antigen processing is based on substrate channeling and review recent studies from the antigen processing and cell biology fields that provide a starting point for testing this hypothesis.
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Affiliation(s)
- Jonathan W Yewdell
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD 20892, USA.
| | - Devin Dersh
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD 20892, USA
| | - Robin Fåhraeus
- Inserm, 27 rue Juliette Dodu, 750 10 Paris, France; International Centre for Cancer Vaccine Science (ICCVS), University of Gdańsk, Science, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland; Department of Medical Biosciences, Umeå University, 90187 Umeå, Sweden; RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 65653 Brno, Czech Republic
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8
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Effect of Protein Denaturation and Enzyme Inhibitors on Proteasomal-Mediated Production of Peptides in Human Embryonic Kidney Cells. Biomolecules 2019; 9:biom9060207. [PMID: 31142026 PMCID: PMC6627375 DOI: 10.3390/biom9060207] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/30/2019] [Accepted: 05/16/2019] [Indexed: 12/13/2022] Open
Abstract
Peptides produced by the proteasome have been proposed to function as signaling molecules that regulate a number of biological processes. In the current study, we used quantitative peptidomics to test whether conditions that affect protein stability, synthesis, or turnover cause changes in the levels of peptides in Human Embryonic Kidney 293T (HEK293T) cells. Mild heat shock (42 °C for 1 h) or treatment with the deubiquitinase inhibitor b-AP15 led to higher levels of ubiquitinated proteins but did not significantly increase the levels of intracellular peptides. Treatment with cycloheximide, an inhibitor of protein translation, did not substantially alter the levels of intracellular peptides identified herein. Cells treated with a combination of epoxomicin and bortezomib showed large increases in the levels of most peptides, relative to the levels in cells treated with either compound alone. Taken together with previous studies, these results support a mechanism in which the proteasome cleaves proteins into peptides that are readily detected in our assays (i.e., 6–37 amino acids) and then further degrades many of these peptides into smaller fragments.
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9
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Abstract
Since the publication of the DRiP (defective ribosomal product) hypothesis in 1996, numerous studies have addressed the contribution of DRiPs to generating viral antigenic peptides for CD8+ T cell immunosurveillance. Here, we review studies characterizing the generation of antigenic peptides from influenza A virus encoded DRiPs, discuss the many remaining mysteries regarding the nature of their co-translational generation, and speculate on where the future might lead.
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10
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Immunoribosomes: Where's there's fire, there's fire. Mol Immunol 2018; 113:38-42. [PMID: 29361306 DOI: 10.1016/j.molimm.2017.12.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/31/2017] [Indexed: 01/13/2023]
Abstract
The MHC class I antigen presentation pathway enables T cell immunosurveillance of cancer cells, viruses and other intracellular pathogens. Rapidly degraded newly synthesized proteins (DRiPs) are a major source of self-, and particularly, viral antigenic peptides. A number of findings support the idea that a substantial fraction of antigenic peptides are synthesized by "immunoribosomes", a subset of translating ribosomes that generate class I peptides with enhanced efficiency. Here, we review the evidence for the immunoribosome hypothesis.
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11
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Palmer AL, de Jong A, Leestemaker Y, Geurink PP, Wijdeven RH, Ovaa H, Dolan BP. Inhibition of the Deubiquitinase Usp14 Diminishes Direct MHC Class I Antigen Presentation. THE JOURNAL OF IMMUNOLOGY 2017; 200:928-936. [PMID: 29282303 DOI: 10.4049/jimmunol.1700273] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 11/22/2017] [Indexed: 11/19/2022]
Abstract
Infected or transformed cells must present peptides derived from endogenous proteins on MHC class I molecules to be recognized and targeted for elimination by Ag-specific cytotoxic T cells. In the first step of peptide generation, proteins are degraded by the proteasome. In this study, we investigated the role of the ubiquitin-specific protease 14 (Usp14), a proteasome-associated deubiquitinase, in direct Ag presentation using a ligand-stabilized model protein expressed as a self-antigen. Chemical inhibition of Usp14 diminished direct presentation of the model antigenic peptide, and the effect was especially pronounced when presentation was restricted to the defective ribosomal product (DRiP) form of the protein. Additionally, presentation specifically from DRiP Ags was diminished by expression of a catalytically inactive form of Usp14. Usp14 inhibition did not appreciably alter protein synthesis and only partially delayed protein degradation as measured by a slight increase in the half-life of the model protein when its degradation was induced. Taken together, these data indicate that functional Usp14 enhances direct Ag presentation, preferentially of DRiP-derived peptides, suggesting that the processing of DRiPs is in some ways different from other forms of Ag.
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Affiliation(s)
- Amy L Palmer
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331
| | - Annemieke de Jong
- Division of Cell Biology II, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and
| | - Yves Leestemaker
- Division of Cell Biology II, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and.,Department of Chemical Immunology, Leiden University Medical Center, 2333 ZC Leiden, the Netherlands
| | - Paul P Geurink
- Division of Cell Biology II, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and.,Department of Chemical Immunology, Leiden University Medical Center, 2333 ZC Leiden, the Netherlands
| | - Ruud H Wijdeven
- Division of Cell Biology II, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and.,Department of Chemical Immunology, Leiden University Medical Center, 2333 ZC Leiden, the Netherlands
| | - Huib Ovaa
- Division of Cell Biology II, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and.,Department of Chemical Immunology, Leiden University Medical Center, 2333 ZC Leiden, the Netherlands
| | - Brian P Dolan
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331;
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12
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Dersh D, Yewdell JW. I've got algorithm: predicting tumor and autoimmune peptide targets for CD8+ T cells. J Clin Invest 2016; 126:4399-4401. [PMID: 27841762 DOI: 10.1172/jci91302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
CD8+ T cells play a central role in eradicating intracellular pathogens, but also are important for noninfectious diseases, including cancer and autoimmunity. The ability to clinically manipulate CD8+ T cells to target cancer and autoimmune disease is limited by our ignorance of relevant self-peptide target antigens. In this issue of the JCI, Pearson et al. describe 25,270 MHC class I-associated peptides presented by a wide range of HLA A and B allomorphs expressed by 18 different B cell lines. Via extensive bioinformatic analysis, the authors make surprising conclusions regarding the selective nature of peptide generation at the level of individual gene products and create a predictive algorithm for disease-relevant self-peptides that will be of immediate use for clinical and basic immunological research.
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13
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Tan Q, Ma S, Hu J, Chen X, Yu Y, Zang G, Tang Z. Role of tripeptidyl peptidase II in MHC class I antigen presentation: Biological characteristics, cellular crosstalk and signaling. Biomed Pharmacother 2016; 84:1954-1958. [PMID: 27829551 DOI: 10.1016/j.biopha.2016.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/28/2016] [Accepted: 11/01/2016] [Indexed: 01/29/2023] Open
Abstract
Tripeptidyl peptidase II (TPPII) is a multifunctional cytoplasmic serine protease. The main function of TPPII is to cleave proteasome-generated peptides into tripeptides, which can then be further degraded into free amino acids. Recent evidence suggests that TPPII plays an important role in epitope generation, but the mechanisms of TPPII in MHC class I antigen presentation remain unclear. Recent research has shed new light on the mechanisms and functions of TPPII in MHC class I antigen presentation. We therefore provide an updated review of the biological characteristics of TPPII and explore its role in MHC class I antigen presentation.
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Affiliation(s)
- Quanhui Tan
- Department of Infectious Disease, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Siyuan Ma
- Department of Infectious Disease, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Jianjun Hu
- Department of Infectious Disease, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Xiaohua Chen
- Department of Infectious Disease, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Yongsheng Yu
- Department of Infectious Disease, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Guoqing Zang
- Department of Infectious Disease, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Zhenghao Tang
- Department of Infectious Disease, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai 200233, China.
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14
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Norbury CC. Defining cross presentation for a wider audience. Curr Opin Immunol 2016; 40:110-6. [DOI: 10.1016/j.coi.2016.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 04/03/2016] [Indexed: 01/10/2023]
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15
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Proteogenomic-based discovery of minor histocompatibility antigens with suitable features for immunotherapy of hematologic cancers. Leukemia 2016; 30:1344-54. [PMID: 26857467 DOI: 10.1038/leu.2016.22] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/02/2016] [Accepted: 01/10/2016] [Indexed: 12/19/2022]
Abstract
Pre-clinical studies have shown that injection of allogeneic T cells primed against a single minor histocompatibility antigen (MiHA) could cure hematologic cancers (HC) without causing any toxicity to the host. However, translation of this approach in humans has been hampered by the paucity of molecularly defined human MiHAs. Using a novel proteogenomic approach, we have analyzed cells from 13 volunteers and discovered a vast repertoire of MiHAs presented by the most common HLA haplotype in European Americans: HLA-A*02:01;B*44:03. Notably, out of >6000 MiHAs, we have identified a set of 39 MiHAs that share optimal features for immunotherapy of HCs. These 'optimal MiHAs' are coded by common alleles of genes that are preferentially expressed in hematopoietic cells. Bioinformatic modeling based on MiHA allelic frequencies showed that the 39 optimal MiHAs would enable MiHA-targeted immunotherapy of practically all HLA-A*02:01;B*44:03 patients. Further extension of this strategy to a few additional HLA haplotypes would allow treatment of almost all patients.
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16
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Enhanced Direct Major Histocompatibility Complex Class I Self-Antigen Presentation Induced by Chlamydia Infection. Infect Immun 2015; 84:480-90. [PMID: 26597986 DOI: 10.1128/iai.01254-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 11/17/2015] [Indexed: 11/20/2022] Open
Abstract
The direct major histocompatibility complex (MHC) class I antigen presentation pathway ensures intracellular peptides are displayed at the cellular surface for recognition of infected or transformed cells by CD8(+) cytotoxic T lymphocytes. Chlamydia spp. are obligate intracellular bacteria and, as such, should be targeted by CD8(+) T cells. It is likely that Chlamydia spp. have evolved mechanisms to avoid the CD8(+) killer T cell responses by interfering with MHC class I antigen presentation. Using a model system of self-peptide presentation which allows for posttranslational control of the model protein's stability, we tested the ability of various Chlamydia species to alter direct MHC class I antigen presentation. Infection of the JY lymphoblastoid cell line limited the accumulation of a model host protein and increased presentation of the model-protein-derived peptides. Enhanced self-peptide presentation was detected only when presentation was restricted to defective ribosomal products, or DRiPs, and total MHC class I levels remained unaltered. Skewed antigen presentation was dependent on a bacterial synthesized component, as evidenced by reversal of the observed phenotype upon preventing bacterial transcription, translation, and the inhibition of bacterial lipooligosaccharide synthesis. These data suggest that Chlamydia spp. have evolved to alter the host antigen presentation machinery to favor presentation of defective and rapidly degraded forms of self-antigen, possibly as a mechanism to diminish the presentation of peptides derived from bacterial proteins.
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17
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Wei J, Gibbs JS, Hickman HD, Cush SS, Bennink JR, Yewdell JW. Ubiquitous Autofragmentation of Fluorescent Proteins Creates Abundant Defective Ribosomal Products (DRiPs) for Immunosurveillance. J Biol Chem 2015; 290:16431-9. [PMID: 25971973 PMCID: PMC4481239 DOI: 10.1074/jbc.m115.658062] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/12/2015] [Indexed: 11/06/2022] Open
Abstract
Green fluorescent protein (GFP) and other fluorescent proteins are essential tools for biological research. When fused to peptides or proteins as a reporter, GFP enables localization and quantitation of gene products in otherwise unmanipulated live cells or organisms. We previously reported that a sizable fraction of nascent GFP is post-translationally converted into a 20-kDa Triton X-100-insoluble proteasome substrate (Qian, S. B., Princiotta, M. F., Bennink, J. R., and Yewdell, J. W. (2006) J. Biol. Chem. 281, 392-400; Dolan, B. P., Li, L., Veltri, C. A., Ireland, C. M., Bennink, J. R., and Yewdell, J. W. (2011) J. Immunol. 186, 2065-2072). Here, we show that a similarly sized fragment is generated by all GFP and red fluorescent protein family members we examined. We demonstrate that fragmentation is a by-product of GFP chromophore rearrangement. A non-rearranging GFP mutant fails to fragment and generates diminished levels of K(b)-SIINFEKL complexes when SIINFEKL is genetically fused to either the C- or N-terminal domains of GFP fusion proteins. Instructively, another fragmenting GFP mutant that cannot create the functional chromophore but still generates fragments also demonstrates diminished K(b)-SIINFEKL generation. However, the mutant and wild-type fragments differ fundamentally in that wild-type fragments are rapidly liberated from the intact molecule and degraded quickly, accounting for increased K(b)-SIINFEKL generation. In the fragmenting mutant, the fragments are generated slowly and remain associated, likely in a native conformation based on their original structural description (Barondeau, D. P., Kassmann, C. J., Tainer, J. A., and Getzoff, E. D. (2006) J. Am. Chem. Soc. 128, 4685-4693). The wild-type GFP fragments represent the first biochemically defined natural defective ribosomal products to contribute peptides for immunosurveillance, enabling quantitation of peptide generation efficiency from this source of defective ribosomal products. More broadly, given the wide use of fluorescent proteins, their ubiquitous and abundant fragmentation must be considered when interpreting experiments using these extremely useful probes.
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Affiliation(s)
- Jiajie Wei
- From the Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - James S Gibbs
- From the Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Heather D Hickman
- From the Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Stephanie S Cush
- From the Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Jack R Bennink
- From the Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Jonathan W Yewdell
- From the Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892
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18
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Chemical biology strategies for posttranslational control of protein function. ACTA ACUST UNITED AC 2015; 21:1238-52. [PMID: 25237866 DOI: 10.1016/j.chembiol.2014.08.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 08/08/2014] [Accepted: 08/25/2014] [Indexed: 02/07/2023]
Abstract
A common strategy to understand a biological system is to selectively perturb it and observe its response. Although technologies now exist to manipulate cellular systems at the genetic and transcript level, the direct manipulation of functions at the protein level can offer significant advantages in precision, speed, and reversibility. Combining the specificity of genetic manipulation and the spatiotemporal resolution of light- and small molecule-based approaches now allows exquisite control over biological systems to subtly perturb a system of interest in vitro and in vivo. Conditional perturbation mechanisms may be broadly characterized by change in intracellular localization, intramolecular activation, or degradation of a protein-of-interest. Here we review recent advances in technologies for conditional regulation of protein function and suggest further areas of potential development.
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19
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Shastri N, Yewdell JW. Editorial overview: Antigen processing and presentation: Where cellular immunity begins. Curr Opin Immunol 2015; 34:v-vii. [PMID: 25964203 DOI: 10.1016/j.coi.2015.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Nilabh Shastri
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
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20
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Goldberg AC, Rizzo LV. MHC structure and function - antigen presentation. Part 2. ACTA ACUST UNITED AC 2015; 13:157-62. [PMID: 25807243 PMCID: PMC4977603 DOI: 10.1590/s1679-45082015rb3123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 06/27/2014] [Indexed: 01/13/2023]
Abstract
The second part of this review deals with the molecules and processes involved in the processing and presentation of the antigenic fragments to the T-cell receptor. Though the nature of the antigens presented varies, the most significant class of antigens is proteins, processed within the cell to be then recognized in the form of peptides, a mechanism that confers an extraordinary degree of precision to this mode of immune response. The efficiency and accuracy of this system is also the result of the myriad of mechanisms involved in the processing of proteins and production of peptides, in addition to the capture and recycling of alternative sources aiming to generate further diversity in the presentation to T-cells.
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21
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How chemistry supports cell biology: the chemical toolbox at your service. Trends Cell Biol 2014; 24:751-60. [PMID: 25108565 DOI: 10.1016/j.tcb.2014.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/10/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
Abstract
Chemical biology is a young and rapidly developing scientific field. In this field, chemistry is inspired by biology to create various tools to monitor and modulate biochemical and cell biological processes. Chemical contributions such as small-molecule inhibitors and activity-based probes (ABPs) can provide new and unique insights into previously unexplored cellular processes. This review provides an overview of recent breakthroughs in chemical biology that are likely to have a significant impact on cell biology. We also discuss the application of several chemical tools in cell biology research.
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22
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Gene Expression Driven by a Strong Viral Promoter in MVA Increases Vaccination Efficiency by Enhancing Antibody Responses and Unmasking CD8⁺ T Cell Epitopes. Vaccines (Basel) 2014; 2:581-600. [PMID: 26344747 PMCID: PMC4494220 DOI: 10.3390/vaccines2030581] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/09/2014] [Accepted: 06/25/2014] [Indexed: 01/11/2023] Open
Abstract
Viral vectors are promising tools for vaccination strategies and immunotherapies. However, CD8+ T cell responses against pathogen-derived epitopes are usually limited to dominant epitopes and antibody responses to recombinant encoded antigens (Ags) are mostly weak. We have previously demonstrated that the timing of viral Ag expression in infected professional Ag-presenting cells strongly shapes the epitope immunodominance hierarchy. T cells recognizing determinants derived from late viral proteins have a clear disadvantage to proliferate during secondary responses. In this work we evaluate the effect of overexpressing the recombinant Ag using the modified vaccinia virus early/late promoter H5 (mPH5). Although the Ag-expression from the natural promoter 7.5 (P7.5) and the mPH5 seemed similar, detailed analysis showed that mPH5 not only induces higher expression levels than P7.5 during early phase of infection, but also Ag turnover is enhanced. The strong overexpression during the early phase leads to broader CD8 T cell responses, while preserving the priming efficiency of stable Ags. Moreover, the increase in Ag-secretion favors the induction of strong antibody responses. Our findings provide the rationale to develop new strategies for fine-tuning the responses elicited by recombinant modified vaccinia virus Ankara by using selected promoters to improve the performance of this viral vector.
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23
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Antón LC, Yewdell JW. Translating DRiPs: MHC class I immunosurveillance of pathogens and tumors. J Leukoc Biol 2014; 95:551-62. [PMID: 24532645 PMCID: PMC3958739 DOI: 10.1189/jlb.1113599] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/15/2014] [Accepted: 01/19/2014] [Indexed: 11/24/2022] Open
Abstract
MHC class I molecules display oligopeptides on the cell surface to enable T cell immunosurveillance of intracellular pathogens and tumors. Speed is of the essence in detecting viruses, which can complete a full replication cycle in just hours, whereas tumor detection is typically a finding-the-needle-in-the-haystack exercise. We review current evidence supporting a nonrandom, compartmentalized selection of peptidogenic substrates that focuses on rapidly degraded translation products as a main source of peptide precursors to optimize immunosurveillance of pathogens and tumors.
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Affiliation(s)
- Luis C Antón
- 1.NIAID, NIH, Bldg. 33, Bethesda, MD 20892, USA.
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24
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Cassidy SA, Cheent KS, Khakoo SI. Effects of Peptide on NK cell-mediated MHC I recognition. Front Immunol 2014; 5:133. [PMID: 24744756 PMCID: PMC3978238 DOI: 10.3389/fimmu.2014.00133] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 03/17/2014] [Indexed: 11/13/2022] Open
Abstract
The inhibitory receptors for MHC class I have a central role in controlling natural killer (NK) cell activity. Soon after their discovery, it was found that these receptors have a degree of peptide selectivity. Such peptide selectivity has been demonstrated for all inhibitory killer cell immunoglobulin-like receptor (KIR) tested to date, certain activating KIR, and also members of the C-type lectin-like family of receptors. This selectivity is much broader than the peptide specificity of T cell receptors, with NK cell receptors recognizing peptide motifs, rather than individual peptides. Inhibitory receptors on NK cells can survey the peptide:MHC complexes expressed on the surface of target cells, therefore subsequent transduction of an inhibitory signal depends on the overall peptide content of these MHC class I complexes. Functionally, KIR-expressing NK cells have been shown to be unexpectedly sensitive to changes in the peptide content of MHC class I, as peptide:MHC class I complexes that weakly engage KIR can antagonize the inhibitory signals generated by engagement of stronger KIR-binding peptide:MHC class I complexes. This property provides KIR-expressing NK cells with the potential to recognize changes in the peptide:MHC class I repertoire, which may occur during viral infections and tumorigenesis. By contrast, in the presence of HLA class I leader peptides, virus-derived peptides can induce a synergistic inhibition of CD94:NKG2A-expressing NK cells through recruitment of CD94 in the absence of NKG2A. On the other hand, CD94:NKG2A-positive NK cells can be exquisitely sensitive to changes in the levels of MHC class I. Peptide antagonism and sensitivity to changes in MHC class I levels are properties that distinguish KIR and CD94:NKG2A. The subtle difference in the properties of NK cells expressing these receptors provides a rationale for having complementary inhibitory receptor systems for MHC class I.
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Affiliation(s)
| | | | - Salim I. Khakoo
- Clinical and Experimental Sciences, Faculty of Medicine, Southampton General Hospital, University of Southampton, Southampton, UK
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25
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Rock KL, Farfán-Arribas DJ, Colbert JD, Goldberg AL. Re-examining class-I presentation and the DRiP hypothesis. Trends Immunol 2014; 35:144-52. [PMID: 24566257 DOI: 10.1016/j.it.2014.01.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 01/16/2014] [Accepted: 01/21/2014] [Indexed: 01/03/2023]
Abstract
MHC class I molecules present peptides derived from intracellular proteins, enabling immune surveillance by CD8(+) T cells and the elimination of virus-infected and cancerous cells. It has been argued that the dominant source of MHC class I-presented peptides is through proteasomal degradation of newly synthesized defective proteins, termed defective ribosomal products (DRiPs). Here, we critically examine the DRiP hypothesis and discuss recent studies indicating that antigenic peptides are generated from the entire proteome and not just from failures in protein synthesis or folding.
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Affiliation(s)
- Kenneth L Rock
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
| | - Diego J Farfán-Arribas
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jeff D Colbert
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
| | - Alfred L Goldberg
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
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26
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Colbert JD, Farfán-Arribas DJ, Rock KL. Substrate-induced protein stabilization reveals a predominant contribution from mature proteins to peptides presented on MHC class I. THE JOURNAL OF IMMUNOLOGY 2013; 191:5410-9. [PMID: 24174619 DOI: 10.4049/jimmunol.1300078] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The origin of the MHC class I-presented peptides are thought to be primarily from newly synthesized but defective proteins, termed defective ribosomal products. Most of the data supporting this concept come from studies in which inhibitors of protein synthesis were found to rapidly block Ag presentation even when cells contained a pool of mature proteins. However, these data only indirectly address the origin of presented peptides, and in most studies, the contribution of mature functional proteins to the class I peptide pool has not been directly quantified. In this report, we address the efficiency and contribution of mature proteins using a tetracycline-inducible system to express Ags that are conditionally stabilized upon ligand binding. This system circumvents the use of general inhibitors of protein synthesis to control Ag expression. Moreover, by controlling Ag stabilization, we could investigate whether the degradation of mature Ags contributed to Ag presentation at early and/or late time points. We show that mature proteins are the major contributor of peptides presented on class I for two distinct antigenic constructs. Furthermore, our data show that the protein synthesis inhibitors used previously to test the contribution of defective proteins actually block Ag presentation in ways that are independent from blocking Ag synthesis. These data suggest that for the constructs we have analyzed, mature functional proteins, rather than defective ribosomal products, are the predominant source of MHC class I-presented peptides.
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Affiliation(s)
- Jeff D Colbert
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
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27
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Chu BW, Kovary KM, Guillaume J, Chen LC, Teruel MN, Wandless TJ. The E3 ubiquitin ligase UBE3C enhances proteasome processivity by ubiquitinating partially proteolyzed substrates. J Biol Chem 2013; 288:34575-87. [PMID: 24158444 DOI: 10.1074/jbc.m113.499350] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
To maintain protein homeostasis, cells must balance protein synthesis with protein degradation. Accumulation of misfolded or partially degraded proteins can lead to the formation of pathological protein aggregates. Here we report the use of destabilizing domains, proteins whose folding state can be reversibly tuned using a high affinity ligand, as model substrates to interrogate cellular protein quality control mechanisms in mammalian cells using a forward genetic screen. Upon knockdown of UBE3C, an E3 ubiquitin ligase, a reporter protein consisting of a destabilizing domain fused to GFP is degraded more slowly and incompletely by the proteasome. Partial proteolysis is also observed when UBE3C is present but cannot ubiquitinate substrates because its active site has been mutated, it is unable to bind to the proteasome, or the substrate lacks lysine residues. UBE3C knockdown also results in less substrate polyubiquitination. Finally, knockdown renders cells more susceptible to the Hsp90 inhibitor 17-AAG, suggesting that UBE3C protects against the harmful accumulation of protein fragments arising from incompletely degraded proteasome substrates.
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Affiliation(s)
- Bernard W Chu
- From the Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305
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28
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Abstract
The field of antigen processing and presentation has taken tremendous strides since the first international workshop in 1995. While much has been learned, much remains to be discovered. Here I discuss the most recent findings regarding the nature of substrates for the MHC class I antigen processing pathways which provide glimpses of the mist shrouded features remaining to be discovered.
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29
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Zanker D, Waithman J, Yewdell JW, Chen W. Mixed proteasomes function to increase viral peptide diversity and broaden antiviral CD8+ T cell responses. THE JOURNAL OF IMMUNOLOGY 2013; 191:52-9. [PMID: 23709680 DOI: 10.4049/jimmunol.1300802] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The three proteasome subunits with proteolytic activity are encoded by standard or immunoproteasome genes. Many proteasomes expressed by normal cells and cells exposed to cytokines are "mixed", that is, contain both standard and immunoproteasome subunits. Using a panel of 38 defined influenza A virus-derived epitopes recognized by C57BL/6 mouse CD8(+) T cells, we used mice with targeted disruption of β1i, β2i, or β5i/β2i genes to examine the contribution of mixed proteasomes to the immunodominance hierarchy of antiviral CD8(+) T cells. We show that each immunoproteasome subunit has large effects on the primary and recall immunodominance hierarchies due to modulating both the available T cell repertoire and generation of individual epitopes as determined both biochemically and kinetically in Ag presentation assays. These findings indicate that mixed proteasomes function to enhance the diversity of peptides and support a broad CD8(+) T cell response.
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Affiliation(s)
- Damien Zanker
- School of Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
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30
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Croft NP, Smith SA, Wong YC, Tan CT, Dudek NL, Flesch IEA, Lin LCW, Tscharke DC, Purcell AW. Kinetics of antigen expression and epitope presentation during virus infection. PLoS Pathog 2013; 9:e1003129. [PMID: 23382674 PMCID: PMC3561264 DOI: 10.1371/journal.ppat.1003129] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 11/26/2012] [Indexed: 01/20/2023] Open
Abstract
Current knowledge about the dynamics of antigen presentation to T cells during viral infection is very poor despite being of fundamental importance to our understanding of anti-viral immunity. Here we use an advanced mass spectrometry method to simultaneously quantify the presentation of eight vaccinia virus peptide-MHC complexes (epitopes) on infected cells and the amounts of their source antigens at multiple times after infection. The results show a startling 1000-fold range in abundance as well as strikingly different kinetics across the epitopes monitored. The tight correlation between onset of protein expression and epitope display for most antigens provides the strongest support to date that antigen presentation is largely linked to translation and not later degradation of antigens. Finally, we show a complete disconnect between the epitope abundance and immunodominance hierarchy of these eight epitopes. This study highlights the complexity of viral antigen presentation by the host and demonstrates the weakness of simple models that assume total protein levels are directly linked to epitope presentation and immunogenicity. A major mechanism for the detection of virus infection is the recognition by T cells of short peptide fragments (epitopes) derived from the degradation of intracellular proteins presented at the cell surface in a complex with class I MHC. Whilst the mechanics of antigen degradation and the loading of peptides onto MHC are now well understood, the kinetics of epitope presentation have only been studied for individual model antigens. We addressed this issue by studying vaccinia virus, best known as the smallpox vaccine, using advanced mass spectrometry. Precise and simultaneous quantification of multiple peptide-MHC complexes showed that the surface of infected cells provides a surprisingly dynamic landscape from the point of view of anti-viral T cells. Further, concurrent measurement of virus protein levels demonstrated that in most cases, peak presentation of epitopes occurs at the same time or precedes the time of maximum protein build up. Finally, we found a complete disconnect between the abundance of epitopes on infected cells and the size of the responding T cell populations. These data provide new insights into how virus infected cells are seen by T cells, which is crucial to our understanding of anti-viral immunity and development of vaccines.
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Affiliation(s)
- Nathan P. Croft
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Stewart A. Smith
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Yik Chun Wong
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Chor Teck Tan
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Nadine L. Dudek
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Inge E. A. Flesch
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Leon C. W. Lin
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - David C. Tscharke
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (DCT); (AWP)
| | - Anthony W. Purcell
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (DCT); (AWP)
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31
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Fiebiger BM, Moosmann A, Behrends U, Mautner J. Mature proteins derived from Epstein-Barr virus fail to feed into the MHC class I antigenic pool. Eur J Immunol 2012; 42:3167-73. [PMID: 22944914 DOI: 10.1002/eji.201242627] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 07/27/2012] [Accepted: 08/30/2012] [Indexed: 11/09/2022]
Abstract
The immediate presentation of peptide epitopes on MHC class I (MHC I) after antigen expression has led to the concept that MHC I ligands are mostly derived from defective ribosomal products (DRiPs), a subset of newly synthesized proteins that are rapidly degraded by the proteasome. Whether and to what extent mature proteins contribute to the antigenic pool, however, has remained elusive. Here, we developed a conditional antigen expression system that allows studying antigen presentation from mature proteins by inducing their rapid proteasomal degradation in the absence of further antigen synthesis. Target cells in which expression of two Epstein-Barr virus (EBV) antigens was induced were rapidly recognized by antigen-specific CD8(+) T cells in a time- and dosage-dependent manner, demonstrating that antigen presentation was linked to antigen synthesis. By contrast, T cells failed to recognize target cells containing large amounts of mature protein even after induction of their rapid proteasomal degradation. Thus, the presentation of these antigens proved to be strictly dependent on protein synthesis whereas mature proteins failed to furnish the antigenic pool. These results have implications for the design of immunotherapeutic strategies that aim at targeting proteins with increased half-lives and are hence overexpressed in tumors.
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Affiliation(s)
- Benjamin M Fiebiger
- Clinical Cooperation Group Pediatric Tumor Immunology, Helmholtz-Zentrum München, München, Germany
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