1
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Mishto M, Takala I, Bonfanti P, Liepe J. Proteasome isoforms in human thymi and mouse models. Immunol Lett 2024; 269:106899. [PMID: 39019403 DOI: 10.1016/j.imlet.2024.106899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 07/02/2024] [Accepted: 07/13/2024] [Indexed: 07/19/2024]
Abstract
The thymus is the organ where functional and self-tolerant T cells are selected through processes of positive and negative selection before migrating to the periphery. The antigenic peptides presented on MHC class I molecules of thymic epithelial cells (TECs) in the cortex and medulla of the thymus are key players in these processes. It has been theorized that these cells express different proteasome isoforms, which generate MHC class I immunopeptidomes with features that differentiate cortex and medulla, and hence positive and negative CD8+ T cell selection. This theory is largely based on mouse models and does not consider the large variety of noncanonical antigenic peptides that could be produced by proteasomes and presented on MHC class I molecules. Here, we review the multi-omics, biochemical and cellular studies carried out on mouse models and human thymi to investigate their content of proteasome isoforms, briefly summarize the implication that noncanonical antigenic peptide presentation in the thymus could have on CD8+ T cell repertoire and put these aspects in the larger framework of anatomical and immunological differences between these two species.
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Affiliation(s)
- Michele Mishto
- Molecular Immunology laboratory, the Francis Crick Institute, NW1 1AT London, United Kingdom; Centre for Inflammation Biology and Cancer Immunology & Peter Gorer Department of Immunobiology, King's College London, SE1 1UL London, United Kingdom.
| | - Iina Takala
- Research group of Quantitative System Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Paola Bonfanti
- Epithelial Stem Cell Biology & Regenerative Medicine laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom; Institute of Immunity & Transplantation, Division of Infection & Immunity, UCL, Pears Building, London NW3 2PP, United Kingdom
| | - Juliane Liepe
- Research group of Quantitative System Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
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2
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van Midden KP, Mantz M, Fonovič M, Gazvoda M, Svete J, Huesgen PF, van der Hoorn RAL, Klemenčič M. Mechanistic insights into CrCEP1: A dual-function cysteine protease with endo- and transpeptidase activity. Int J Biol Macromol 2024; 271:132505. [PMID: 38768911 DOI: 10.1016/j.ijbiomac.2024.132505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 04/05/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
Proteases, essential regulators of plant stress responses, remain enigmatic in their precise functional roles. By employing activity-based probes for real-time monitoring, this study aimed to delve into protease activities in Chlamydomonas reinhardtii exposed to oxidative stress induced by hydrogen peroxide. However, our work revealed that the activity-based probes strongly labelled three non-proteolytic proteins-PsbO, PsbP, and PsbQ-integral components of photosystem II's oxygen-evolving complex. Subsequent biochemical assays and mass spectrometry experiments revealed the involvement of CrCEP1, a previously uncharacterized papain-like cysteine protease, as the catalyst of this labelling reaction. Further experiments with recombinant CrCEP1 and PsbO proteins replicated the reaction in vitro. Our data unveiled that endopeptidase CrCEP1 also has transpeptidase activity, ligating probes and peptides to the N-termini of Psb proteins, thereby expanding the repertoire of its enzymatic activities. The hitherto unknown transpeptidase activity of CrCEP1, working in conjunction with its proteolytic activity, unveils putative complex and versatile roles for proteases in cellular processes during stress responses.
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Affiliation(s)
- Katarina P van Midden
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Melissa Mantz
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany; CECAD, Medical Faculty and University Hospital, University of Cologne, 50931 Cologne, Germany
| | - Marko Fonovič
- Department of Biochemistry, Molecular and Structural Biology, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Martin Gazvoda
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Jurij Svete
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Pitter F Huesgen
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany; CECAD, Medical Faculty and University Hospital, University of Cologne, 50931 Cologne, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany; CIBSS- Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | | | - Marina Klemenčič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia.
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3
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Soh WT, Roetschke HP, Cormican JA, Teo BF, Chiam NC, Raabe M, Pflanz R, Henneberg F, Becker S, Chari A, Liu H, Urlaub H, Liepe J, Mishto M. Protein degradation by human 20S proteasomes elucidates the interplay between peptide hydrolysis and splicing. Nat Commun 2024; 15:1147. [PMID: 38326304 PMCID: PMC10850103 DOI: 10.1038/s41467-024-45339-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 01/17/2024] [Indexed: 02/09/2024] Open
Abstract
If and how proteasomes catalyze not only peptide hydrolysis but also peptide splicing is an open question that has divided the scientific community. The debate has so far been based on immunopeptidomics, in vitro digestions of synthetic polypeptides as well as ex vivo and in vivo experiments, which could only indirectly describe proteasome-catalyzed peptide splicing of full-length proteins. Here we develop a workflow-and cognate software - to analyze proteasome-generated non-spliced and spliced peptides produced from entire proteins and apply it to in vitro digestions of 15 proteins, including well-known intrinsically disordered proteins such as human tau and α-Synuclein. The results confirm that 20S proteasomes produce a sizeable variety of cis-spliced peptides, whereas trans-spliced peptides are a minority. Both peptide hydrolysis and splicing produce peptides with well-defined characteristics, which hint toward an intricate regulation of both catalytic activities. At protein level, both non-spliced and spliced peptides are not randomly localized within protein sequences, but rather concentrated in hotspots of peptide products, in part driven by protein sequence motifs and proteasomal preferences. At sequence level, the different peptide sequence preference of peptide hydrolysis and peptide splicing suggests a competition between the two catalytic activities of 20S proteasomes during protein degradation.
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Affiliation(s)
- Wai Tuck Soh
- Research Group of Quantitative and Systems Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Hanna P Roetschke
- Research Group of Quantitative and Systems Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
- Centre for Inflammation Biology and Cancer Immunology & Peter Gorer Department of Immunobiology, King's College London, SE1 1UL, London, UK
- Research Group of Molecular Immunology, Francis Crick Institute, NW1 1AT, London, UK
| | - John A Cormican
- Research Group of Quantitative and Systems Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Bei Fang Teo
- Centre for Inflammation Biology and Cancer Immunology & Peter Gorer Department of Immunobiology, King's College London, SE1 1UL, London, UK
- Research Group of Molecular Immunology, Francis Crick Institute, NW1 1AT, London, UK
- Immunology Programme, Life Sciences Institute; Immunology Translational Research Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117456, Singapore
| | - Nyet Cheng Chiam
- Research Group of Quantitative and Systems Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Monika Raabe
- Research Group of Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Ralf Pflanz
- Research Group of Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Fabian Henneberg
- Department of Structural Dynamics, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Ashwin Chari
- Research Group of Structural Biochemistry and Mechanisms, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Haiyan Liu
- Immunology Programme, Life Sciences Institute; Immunology Translational Research Program and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117456, Singapore
| | - Henning Urlaub
- Research Group of Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
- Institute of Clinical Chemistry, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Juliane Liepe
- Research Group of Quantitative and Systems Biology, Max-Planck-Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany.
| | - Michele Mishto
- Centre for Inflammation Biology and Cancer Immunology & Peter Gorer Department of Immunobiology, King's College London, SE1 1UL, London, UK.
- Research Group of Molecular Immunology, Francis Crick Institute, NW1 1AT, London, UK.
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4
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Roetschke HP, Rodriguez-Hernandez G, Cormican JA, Yang X, Lynham S, Mishto M, Liepe J. InvitroSPI and a large database of proteasome-generated spliced and non-spliced peptides. Sci Data 2023; 10:18. [PMID: 36627305 PMCID: PMC9832164 DOI: 10.1038/s41597-022-01890-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/01/2022] [Indexed: 01/12/2023] Open
Abstract
Noncanonical epitopes presented by Human Leucocyte Antigen class I (HLA-I) complexes to CD8+ T cells attracted the spotlight in the research of novel immunotherapies against cancer, infection and autoimmunity. Proteasomes, which are the main producers of HLA-I-bound antigenic peptides, can catalyze both peptide hydrolysis and peptide splicing. The prediction of proteasome-generated spliced peptides is an objective that still requires a reliable (and large) database of non-spliced and spliced peptides produced by these proteases. Here, we present an extended database of proteasome-generated spliced and non-spliced peptides, which was obtained by analyzing in vitro digestions of 80 unique synthetic polypeptide substrates, measured by different mass spectrometers. Peptides were identified through invitroSPI method, which was validated through in silico and in vitro strategies. The peptide product database contains 16,631 unique peptide products (5,493 non-spliced, 6,453 cis-spliced and 4,685 trans-spliced peptide products), and a substrate sequence variety that is a valuable source for predictors of proteasome-catalyzed peptide hydrolysis and splicing. Potential artefacts and skewed results due to different identification and analysis strategies are discussed.
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Affiliation(s)
- Hanna P Roetschke
- Max-Planck-Institute for Multidisciplinary Sciences (MPI-NAT), 37077, Göttingen, Germany
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) & Peter Gorer Department of Immunobiology, King's College London (KCL), SE1 1UL, London, UK
| | - Guillermo Rodriguez-Hernandez
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) & Peter Gorer Department of Immunobiology, King's College London (KCL), SE1 1UL, London, UK
- Francis Crick Institute, NW1 1AT, London, UK
| | - John A Cormican
- Max-Planck-Institute for Multidisciplinary Sciences (MPI-NAT), 37077, Göttingen, Germany
| | - Xiaoping Yang
- Proteomics Core Facility, James Black Centre, King's College London (KCL), SE5 9NU, London, UK
| | - Steven Lynham
- Proteomics Core Facility, James Black Centre, King's College London (KCL), SE5 9NU, London, UK
| | - Michele Mishto
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) & Peter Gorer Department of Immunobiology, King's College London (KCL), SE1 1UL, London, UK.
- Francis Crick Institute, NW1 1AT, London, UK.
| | - Juliane Liepe
- Max-Planck-Institute for Multidisciplinary Sciences (MPI-NAT), 37077, Göttingen, Germany.
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5
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Kloetzel PM. Neo-Splicetopes in Tumor Therapy: A Lost Case? Front Immunol 2022; 13:849863. [PMID: 35265089 PMCID: PMC8898901 DOI: 10.3389/fimmu.2022.849863] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
Proteasome generates spliced peptides by ligating two distant cleavage products in a reverse proteolysis reaction. The observation that CD8+ T cells recognizing a spliced peptide induced T cell rejection in a melanoma patient following adoptive T cell transfer (ATT), raised some hopes with regard to the general therapeutic and immune relevance of spliced peptides. Concomitantly, the identification of spliced peptides was also the start of a controversy with respect to their frequency, abundancy and their therapeutic applicability. Here I review some of the recent evidence favoring or disfavoring an immune relevance of splicetopes and discuss from a theoretical point of view the potential usefulness of tumor specific splicetopes and why against all odds it still may seem worth trying to identify such tumor and patient-specific neosplicetopes for application in ATT.
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Affiliation(s)
- Peter M Kloetzel
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biochemistry, Berlin, Germany
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6
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Mishto M. Commentary: Are There Indeed Spliced Peptides in the Immunopeptidome? Mol Cell Proteomics 2021; 20:100158. [PMID: 34607014 PMCID: PMC8724881 DOI: 10.1016/j.mcpro.2021.100158] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/22/2021] [Accepted: 09/27/2021] [Indexed: 11/27/2022] Open
Abstract
Proteasome-generated spliced epitopes presented by HLA class I complexes are emerging targets for T cell targeted immunotherapies. Their identification by mass spectrometry triggered heated debates, which find a representative opinion in one of the two fronts in the recent perspective article by Arie Admon. Briefly, he suggests that proteasomes cannot efficiently catalyze such a reaction, and, thus, that all spliced peptides identified in HLA class I immunopeptidomes and other specimens are artifacts. This hypothesis is in contrast with in vitro, in cellula, and in vivo results published since the discovery of proteasome-catalyzed peptide splicing in 2004.
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Affiliation(s)
- Michele Mishto
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) & Peter Gorer Department of Immunobiology, King's College London, London, United Kingdom; Francis Crick Institute, London, United Kingdom.
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7
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Reed B, Crawford F, Hill RC, Jin N, White J, Krovi SH, Marrack P, Hansen K, Kappler JW. Lysosomal cathepsin creates chimeric epitopes for diabetogenic CD4 T cells via transpeptidation. J Exp Med 2021; 218:211485. [PMID: 33095259 PMCID: PMC7590512 DOI: 10.1084/jem.20192135] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 08/06/2020] [Accepted: 09/10/2020] [Indexed: 01/15/2023] Open
Abstract
The identification of the peptide epitopes presented by major histocompatibility complex class II (MHCII) molecules that drive the CD4 T cell component of autoimmune diseases has presented a formidable challenge over several decades. In type 1 diabetes (T1D), recent insight into this problem has come from the realization that several of the important epitopes are not directly processed from a protein source, but rather pieced together by fusion of different peptide fragments of secretory granule proteins to create new chimeric epitopes. We have proposed that this fusion is performed by a reverse proteolysis reaction called transpeptidation, occurring during the catabolic turnover of pancreatic proteins when secretory granules fuse with lysosomes (crinophagy). Here, we demonstrate several highly antigenic chimeric epitopes for diabetogenic CD4 T cells that are produced by digestion of the appropriate inactive fragments of the granule proteins with the lysosomal protease cathepsin L (Cat-L). This pathway has implications for how self-tolerance can be broken peripherally in T1D and other autoimmune diseases.
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Affiliation(s)
- Brendan Reed
- Department of Biomedical Research, National Jewish Health, Denver, CO.,Department of Immunology and Microbiology, Anschutz Medical Campus, University of Colorado, Aurora, CO.,Research Division, Barbara Davis Center for Diabetes, Anschutz Medical Campus, University of Colorado, Aurora, CO
| | - Frances Crawford
- Department of Biomedical Research, National Jewish Health, Denver, CO
| | - Ryan C Hill
- Biochemistry and Molecular Genetics, Anschutz Medical Campus, University of Colorado, Aurora, CO
| | - Niyun Jin
- Department of Biomedical Research, National Jewish Health, Denver, CO.,Department of Immunology and Microbiology, Anschutz Medical Campus, University of Colorado, Aurora, CO.,Research Division, Barbara Davis Center for Diabetes, Anschutz Medical Campus, University of Colorado, Aurora, CO
| | - Janice White
- Department of Biomedical Research, National Jewish Health, Denver, CO
| | - S Harsha Krovi
- Department of Biomedical Research, National Jewish Health, Denver, CO.,Department of Immunology and Microbiology, Anschutz Medical Campus, University of Colorado, Aurora, CO
| | - Philippa Marrack
- Department of Biomedical Research, National Jewish Health, Denver, CO.,Department of Immunology and Microbiology, Anschutz Medical Campus, University of Colorado, Aurora, CO.,Biochemistry and Molecular Genetics, Anschutz Medical Campus, University of Colorado, Aurora, CO
| | - Kirk Hansen
- Biochemistry and Molecular Genetics, Anschutz Medical Campus, University of Colorado, Aurora, CO
| | - John W Kappler
- Department of Biomedical Research, National Jewish Health, Denver, CO.,Department of Immunology and Microbiology, Anschutz Medical Campus, University of Colorado, Aurora, CO.,Research Division, Barbara Davis Center for Diabetes, Anschutz Medical Campus, University of Colorado, Aurora, CO.,Biochemistry and Molecular Genetics, Anschutz Medical Campus, University of Colorado, Aurora, CO
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8
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Mishto M, Rodriguez-Hernandez G, Neefjes J, Urlaub H, Liepe J. Response: Commentary: An In Silico-In Vitro Pipeline Identifying an HLA-A*02:01+ KRAS G12V+ Spliced Epitope Candidate for a Broad Tumor-Immune Response in Cancer Patients. Front Immunol 2021; 12:679836. [PMID: 34326838 PMCID: PMC8315000 DOI: 10.3389/fimmu.2021.679836] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/17/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michele Mishto
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) & Peter Gorer Department of Immunobiology, King's College London, London, United Kingdom
- Francis Crick Institute, London, United Kingdom
| | - Guillermo Rodriguez-Hernandez
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) & Peter Gorer Department of Immunobiology, King's College London, London, United Kingdom
- Francis Crick Institute, London, United Kingdom
| | - Jacques Neefjes
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Center (LUMC), Leiden, Netherlands
| | - Henning Urlaub
- Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
- Bioanalytics, Institute of Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Juliane Liepe
- Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
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9
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Amdare N, Purcell AW, DiLorenzo TP. Noncontiguous T cell epitopes in autoimmune diabetes: From mice to men and back again. J Biol Chem 2021; 297:100827. [PMID: 34044020 PMCID: PMC8233151 DOI: 10.1016/j.jbc.2021.100827] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 11/30/2022] Open
Abstract
Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease that affects the insulin-producing beta cells of the pancreatic islets. The nonobese diabetic mouse is a widely studied spontaneous model of the disease that has contributed greatly to our understanding of T1D pathogenesis. This is especially true in the case of antigen discovery. Upon review of existing knowledge concerning the antigens and peptide epitopes that are recognized by T cells in this model, good concordance is observed between mouse and human antigens. A fascinating recent illustration of the contribution of the nonobese diabetic mouse in the area of epitope identification is the discovery of noncontiguous CD4+ T cell epitopes. This novel epitope class is characterized by the linkage of an insulin-derived peptide to, most commonly, a fragment of a natural cleavage product of another beta cell secretory granule constituent. These so-called hybrid insulin peptides are also recognized by T cells in patients with T1D, although the precise mechanism for their generation has yet to be defined and is the subject of active investigation. Although evidence from the tumor immunology arena documented the existence of noncontiguous CD8+ T cell epitopes, generated by proteasome-mediated peptide splicing involving transpeptidation, such CD8+ T cell epitopes were thought to be a rare immunological curiosity. However, recent advances in bioinformatics and mass spectrometry have challenged this view. These developments, coupled with the discovery of hybrid insulin peptides, have spurred a search for noncontiguous CD8+ T cell epitopes in T1D, an exciting frontier area still in its infancy.
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Affiliation(s)
- Nitin Amdare
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Anthony W Purcell
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Teresa P DiLorenzo
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA; Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA; Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York, USA; The Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, New York, USA.
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10
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Admon A. Are There Indeed Spliced Peptides in the Immunopeptidome? Mol Cell Proteomics 2021; 20:100099. [PMID: 34022431 PMCID: PMC8724635 DOI: 10.1016/j.mcpro.2021.100099] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/13/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022] Open
Abstract
The claims that a large fraction of the immunopeptidome is composed of spliced major histocompatibility complex (MHC) peptides have stirred significant excitement and raised controversy. Here, I suggest that there are likely no spliced peptides in the immunopeptidome, and if they exist at all, they are extremely rare. I base this claim on both biochemical and bioinformatics considerations. First, as a reactant in normal proteolytic reactions, water will compete with transpeptidation, which has been suggested as the mechanism of peptide splicing. The high mobility and abundance of water in aqueous solutions renders transpeptidation very inefficient and therefore unlikely to occur. Second, new studies have refuted the bioinformatics assignments to spliced peptides of most of the immunopeptidome MS data, suggesting that the correct assignments are likely other canonical, noncanonical, and post-translationally modified peptides. Therefore, I call for rigorous experimental methodology using heavy stable isotope peptides spiking into the immunoaffinity-purified mixtures of natural MHC peptides and analysis by the highly reliable targeted MS, to claim that MHC peptides are indeed spliced. Peptide splicing was suggested to contribute to the immunopeptidome. I suggest that this idea should be reconsidered based on new evidences. Both biochemical and bioinformatics considerations argue against peptide splicing.
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Affiliation(s)
- Arie Admon
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
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11
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Reed BK, Kappler JW. Hidden in Plain View: Discovery of Chimeric Diabetogenic CD4 T Cell Neo-Epitopes. Front Immunol 2021; 12:669986. [PMID: 33986758 PMCID: PMC8111216 DOI: 10.3389/fimmu.2021.669986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
The T cell antigens driving autoimmune Type 1 Diabetes (T1D) have been pursued for more than three decades. When diabetogenic CD4 T cell clones and their relevant MHCII antigen presenting alleles were first identified in rodents and humans, the path to discovering the peptide epitopes within pancreatic beta cell proteins seemed straightforward. However, as experimental results accumulated, definitive data were often absent or controversial. Work within the last decade has helped to clear up some of the controversy by demonstrating that a number of the important MHCII presented epitopes are not encoded in the natural beta cell proteins, but in fact are fusions between peptide fragments derived from the same or different proteins. Recently, the mechanism for generating these MHCII diabetogenic chimeric epitopes has been attributed to a form of reverse proteolysis, called transpeptidation, a process that has been well-documented in the production of MHCI presented epitopes. In this mini-review we summarize these data and their implications for T1D and other autoimmune responses.
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Affiliation(s)
- Brendan K Reed
- Research Division, Barbara Davis Center for Diabetes, University of Colorado, Aurora, CO, United States.,Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO, United States.,Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States
| | - John W Kappler
- Research Division, Barbara Davis Center for Diabetes, University of Colorado, Aurora, CO, United States.,Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO, United States.,Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States.,Biochemistry and Molecular Genetics, University of Colorado, Aurora, CO, United States
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12
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Thibodeau J, Bourgeois-Daigneault MC, Lapointe R. Targeting the MHC Class II antigen presentation pathway in cancer immunotherapy. Oncoimmunology 2021; 1:908-916. [PMID: 23162758 PMCID: PMC3489746 DOI: 10.4161/onci.21205] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The success of immunotherapy relies on the participation of all arms of the immune system and the role of CD4+ T lymphocytes in preventing tumor growth is now well established. Understanding how tumors evade immune responses holds the key to the development of cancer immunotherapies. In this review, we discuss how MHC Class II expression varies in cancer cells and how this influences antitumor immune responses. We also discuss the means that are currently available for harnessing the MHC Class II antigen presentation pathway for the development of efficient vaccines to activate the immune system against cancer.
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Affiliation(s)
- Jacques Thibodeau
- Laboratoire d'Immunologie Moléculaire; Département de Microbiologie et Immunologie; Université de Montréal; Montréal, QC Canada
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13
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The MHC-II peptidome of pancreatic islets identifies key features of autoimmune peptides. Nat Immunol 2020; 21:455-463. [PMID: 32152506 PMCID: PMC7117798 DOI: 10.1038/s41590-020-0623-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 02/03/2020] [Indexed: 12/11/2022]
Abstract
The nature of autoantigens that trigger autoimmune diseases has been much discussed, but direct biochemical identification is lacking for most. Addressing this question demands unbiased examination of the self-peptides displayed by a defined autoimmune major histocompatibility complex class II (MHCII) molecule. Here we examined the immunopeptidome of the pancreatic islets in non-obese diabetic (NOD) mice, which spontaneously develop autoimmune diabetes based on the I-Ag7 variant of MHCII. The relevant peptides that induced pathogenic CD4+ T cells at the initiation of diabetes derived from proinsulin. These peptides were also found in the MHCII peptidome of the pancreatic lymph nodes and spleen. The proinsulin-derived peptides followed a trajectory from their generation and exocytosis in β cells, to uptake and presentation in islets and peripheral sites. Such a pathway generated conventional epitopes but also resulted in the presentation of post-translationally modified peptides, including deamidated sequences. These analyses reveal the key features of a restricted component in the self-MHCII peptidome that caused autoreactivity.
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14
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Piganelli JD, Mamula MJ, James EA. The Role of β Cell Stress and Neo-Epitopes in the Immunopathology of Type 1 Diabetes. Front Endocrinol (Lausanne) 2020; 11:624590. [PMID: 33679609 PMCID: PMC7930070 DOI: 10.3389/fendo.2020.624590] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022] Open
Abstract
Due to their secretory function, β cells are predisposed to higher levels of endoplasmic reticulum (ER) stress and greater sensitivity to inflammation than other cell types. These stresses elicit changes in β cells that alter their function and immunogenicity, including defective ribosomal initiation, post-translational modifications (PTMs) of endogenous β cell proteins, and alternative splicing. Multiple published reports confirm the presence of not only CD8+ T cells, but also autoreactive CD4+ T cells within pancreatic islets. Although the specificities of T cells that infiltrate human islets are incompletely characterized, they have been confirmed to include neo-epitopes that are formed through stress-related enzymatic modifications of β cell proteins. This article summarizes emerging knowledge about stress-induced changes in β cells and data supporting a role for neo-antigen formation and cross-talk between immune cells and β cells that provokes autoimmune attack - leading to a breakdown in tissue-specific tolerance in subjects who develop type 1 diabetes.
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Affiliation(s)
- Jon D. Piganelli
- Division of Pediatric Surgery, Department of Surgery, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Mark J. Mamula
- Section of Rheumatology, Department of Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Eddie A. James
- Translational Research Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, United States
- *Correspondence: Eddie A. James,
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15
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Faridi P, Li C, Ramarathinam SH, Vivian JP, Illing PT, Mifsud NA, Ayala R, Song J, Gearing LJ, Hertzog PJ, Ternette N, Rossjohn J, Croft NP, Purcell AW. A subset of HLA-I peptides are not genomically templated: Evidence for cis- and trans-spliced peptide ligands. Sci Immunol 2019; 3:3/28/eaar3947. [PMID: 30315122 DOI: 10.1126/sciimmunol.aar3947] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 05/29/2018] [Accepted: 08/31/2018] [Indexed: 12/19/2022]
Abstract
The diversity of peptides displayed by class I human leukocyte antigen (HLA) plays an essential role in T cell immunity. The peptide repertoire is extended by various posttranslational modifications, including proteasomal splicing of peptide fragments from distinct regions of an antigen to form nongenomically templated cis-spliced sequences. Previously, it has been suggested that a fraction of the immunopeptidome constitutes such cis-spliced peptides; however, because of computational limitations, it has not been possible to assess whether trans-spliced peptides (i.e., the fusion of peptide segments from distinct antigens) are also bound and presented by HLA molecules, and if so, in what proportion. Here, we have developed and applied a bioinformatic workflow and demonstrated that trans-spliced peptides are presented by HLA-I, and their abundance challenges current models of proteasomal splicing that predict cis-splicing as the most probable outcome. These trans-spliced peptides display canonical HLA-binding sequence features and are as frequently identified as cis-spliced peptides found bound to a number of different HLA-A and HLA-B allotypes. Structural analysis reveals that the junction between spliced peptides is highly solvent exposed and likely to participate in T cell receptor interactions. These results highlight the unanticipated diversity of the immunopeptidome and have important implications for autoimmunity, vaccine design, and immunotherapy.
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Affiliation(s)
- Pouya Faridi
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Chen Li
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Department of Biology, Institute of Molecular Systems Biology,ETH Zurich, Zurich 8093, Switzerland
| | - Sri H Ramarathinam
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Julian P Vivian
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Patricia T Illing
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Nicole A Mifsud
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Rochelle Ayala
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Jiangning Song
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Monash Centre for Data Science, Faculty of Information Technology, Monash University, Melbourne, Victoria 3800, Australia
| | - Linden J Gearing
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research and Department of Molecular and Translational Science, School of Clinical Science, Monash University, Clayton, Victoria 3168, Australia
| | - Paul J Hertzog
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research and Department of Molecular and Translational Science, School of Clinical Science, Monash University, Clayton, Victoria 3168, Australia
| | | | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Institute of Infection and Immunity, Cardiff University School of Medicine,Heath Park, Cardiff CF14 4XN, UK
| | - Nathan P Croft
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.
| | - Anthony W Purcell
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.
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16
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Wang Y, Sosinowski T, Novikov A, Crawford F, White J, Jin N, Liu Z, Zou J, Neau D, Davidson HW, Nakayama M, Kwok WW, Gapin L, Marrack P, Kappler JW, Dai S. How C-terminal additions to insulin B-chain fragments create superagonists for T cells in mouse and human type 1 diabetes. Sci Immunol 2019; 4:eaav7517. [PMID: 30952805 PMCID: PMC6929690 DOI: 10.1126/sciimmunol.aav7517] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/04/2019] [Accepted: 02/11/2019] [Indexed: 11/03/2022]
Abstract
In type 1 diabetes (T1D), proinsulin is a major autoantigen and the insulin B:9-23 peptide contains epitopes for CD4+ T cells in both mice and humans. This peptide requires carboxyl-terminal mutations for uniform binding in the proper position within the mouse IAg7 or human DQ8 major histocompatibility complex (MHC) class II (MHCII) peptide grooves and for strong CD4+ T cell stimulation. Here, we present crystal structures showing how these mutations control CD4+ T cell receptor (TCR) binding to these MHCII-peptide complexes. Our data reveal stricking similarities between mouse and human CD4+ TCRs in their interactions with these ligands. We also show how fusions between fragments of B:9-23 and of proinsulin C-peptide create chimeric peptides with activities as strong or stronger than the mutated insulin peptides. We propose transpeptidation in the lysosome as a mechanism that could accomplish these fusions in vivo, similar to the creation of fused peptide epitopes for MHCI presentation shown to occur by transpeptidation in the proteasome. Were this mechanism limited to the pancreas and absent in the thymus, it could provide an explanation for how diabetogenic T cells escape negative selection during development but find their modified target antigens in the pancreas to cause T1D.
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MESH Headings
- Amino Acid Sequence/genetics
- Animals
- Autoantigens/genetics
- Autoantigens/immunology
- Autoantigens/metabolism
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- Cell Line, Tumor
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/immunology
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- HLA-DQ Antigens/immunology
- HLA-DQ Antigens/metabolism
- Humans
- Hybridomas
- Immune Tolerance
- Insulin/genetics
- Insulin/immunology
- Insulin/metabolism
- Lysosomes/immunology
- Lysosomes/metabolism
- Mice
- Mice, Inbred NOD
- Molecular Docking Simulation
- Mutation
- Pancreas/cytology
- Pancreas/immunology
- Pancreas/metabolism
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- Protein Domains/immunology
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Thymus Gland/cytology
- Thymus Gland/immunology
- Thymus Gland/metabolism
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Affiliation(s)
- Yang Wang
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Tomasz Sosinowski
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Andrey Novikov
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - Frances Crawford
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - Janice White
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - Niyun Jin
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Zikou Liu
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - Jinhao Zou
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - David Neau
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Howard W Davidson
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Maki Nakayama
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Laurent Gapin
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Philippa Marrack
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - John W Kappler
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA.
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Structural Biology and Biochemistry program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Shaodong Dai
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA.
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Structural Biology and Biochemistry program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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17
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Liepe J, Sidney J, Lorenz FKM, Sette A, Mishto M. Mapping the MHC Class I-Spliced Immunopeptidome of Cancer Cells. Cancer Immunol Res 2019; 7:62-76. [PMID: 30425108 DOI: 10.1158/2326-6066.cir-18-0424] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/12/2018] [Accepted: 11/08/2018] [Indexed: 11/16/2022]
Abstract
Anticancer immunotherapies demand optimal epitope targets, which could include proteasome-generated spliced peptides if tumor cells were to present them. Here, we show that spliced peptides are widely presented by MHC class I molecules of colon and breast carcinoma cell lines. The peptides derive from hot spots within antigens and enlarge the antigen coverage. Spliced peptides also represent a large number of antigens that would otherwise be neglected by patrolling T cells. These antigens tend to be long, hydrophobic, and basic. Thus, spliced peptides can be a key to identifying targets in an enlarged pool of antigens associated with cancer.
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Affiliation(s)
- Juliane Liepe
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| | - John Sidney
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California
| | - Felix K M Lorenz
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California
| | - Michele Mishto
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) and Peter Gorer Department of Immunobiology, King's College London, London, United Kingdom.
- Charité- Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Biochemie, Berlin, Germany
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18
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Ito Y, Ashenberg O, Pyrdol J, Luoma AM, Rozenblatt-Rosen O, Hofree M, Christian E, Ferrari de Andrade L, Tay RE, Teyton L, Regev A, Dougan SK, Wucherpfennig KW. Rapid CLIP dissociation from MHC II promotes an unusual antigen presentation pathway in autoimmunity. J Exp Med 2018; 215:2617-2635. [PMID: 30185635 PMCID: PMC6170167 DOI: 10.1084/jem.20180300] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 07/03/2018] [Accepted: 08/15/2018] [Indexed: 11/19/2022] Open
Abstract
Spontaneous CLIP dissociation from an autoimmunity-associated MHC II protein enhances presentation of peptides released by insulin-producing β cells. Presentation of such extracellular peptides does not require endosomal antigen processing and augments islet infiltration by CD4 T cells. A number of autoimmunity-associated MHC class II proteins interact only weakly with the invariant chain–derived class II–associated invariant chain peptide (CLIP). CLIP dissociates rapidly from I-Ag7 even in the absence of DM, and this property is related to the type 1 diabetes–associated β57 polymorphism. We generated knock-in non-obese diabetic (NOD) mice with a single amino acid change in the CLIP segment of the invariant chain in order to moderately slow CLIP dissociation from I-Ag7. These knock-in mice had a significantly reduced incidence of spontaneous type 1 diabetes and diminished islet infiltration by CD4 T cells, in particular T cells specific for fusion peptides generated by covalent linkage of proteolytic fragments within β cell secretory granules. Rapid CLIP dissociation enhanced the presentation of such extracellular peptides, thus bypassing the conventional MHC class II antigen-processing pathway. Autoimmunity-associated MHC class II polymorphisms therefore not only modify binding of self-peptides, but also alter the biochemistry of peptide acquisition.
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Affiliation(s)
- Yoshinaga Ito
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA
| | - Orr Ashenberg
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - Jason Pyrdol
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA
| | - Adrienne M Luoma
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA
| | | | - Matan Hofree
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - Elena Christian
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - Lucas Ferrari de Andrade
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA
| | - Rong En Tay
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA
| | - Luc Teyton
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA
| | - Aviv Regev
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - Stephanie K Dougan
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA .,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA
| | - Kai W Wucherpfennig
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA .,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA
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19
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Eom GE, Kim S. Identification of Nucleophilic Probes for Protease-Mediated Transpeptidation. Molecules 2018; 23:E2109. [PMID: 30131476 PMCID: PMC6225416 DOI: 10.3390/molecules23092109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/16/2018] [Accepted: 08/20/2018] [Indexed: 11/16/2022] Open
Abstract
Proteases have evolved to mediate the hydrolysis of peptide bonds but may perform transpeptidation in the presence of a proper nucleophilic molecule that can effectively compete with water to react with the acyl-enzyme intermediate. There have been several examples of protease-mediated transpeptidation, but they are generally inefficient, and little effort has been made to systematically control the transpeptidation activity of other proteases with good nucleophiles. Here, we developed an on-bead screening approach to find a probe that functions efficiently as a nucleophile in the protease-mediated transpeptidation reaction, and we identified good probes for a model protease DegP. These probes were covalently linked to the C-termini of the cleaved peptides in a mild condition and made the selective enrichment of ligated peptides possible. We suggest that good nucleophilic probes can be found for many other proteases that act via acyl-enzyme intermediates, and these probes will help characterize their substrates.
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Affiliation(s)
- Ga-Eul Eom
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
| | - Seokhee Kim
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
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20
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Pishesha N, Ingram JR, Ploegh HL. Sortase A: A Model for Transpeptidation and Its Biological Applications. Annu Rev Cell Dev Biol 2018; 34:163-188. [PMID: 30110557 DOI: 10.1146/annurev-cellbio-100617-062527] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Molecular biologists and chemists alike have long sought to modify proteins with substituents that cannot be installed by standard or even advanced genetic approaches. We here describe the use of transpeptidases to achieve these goals. Living systems encode a variety of transpeptidases and peptide ligases that allow for the enzyme-catalyzed formation of peptide bonds, and protein engineers have used directed evolution to enhance these enzymes for biological applications. We focus primarily on the transpeptidase sortase A, which has become popular over the past few years for its ability to perform a remarkably wide variety of protein modifications, both in vitro and in living cells.
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Affiliation(s)
- Novalia Pishesha
- Program in Molecular and Cellular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA; .,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jessica R Ingram
- Department of Cancer Immunology and Virology, Dana Farber Cancer Institute, Boston, Massachusetts 02215, USA
| | - Hidde L Ploegh
- Program in Molecular and Cellular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA;
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21
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Ramarathinam SH, Croft NP, Illing PT, Faridi P, Purcell AW. Employing proteomics in the study of antigen presentation: an update. Expert Rev Proteomics 2018; 15:637-645. [PMID: 30080115 DOI: 10.1080/14789450.2018.1509000] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Our immune system discriminates self from non-self by examining the peptide cargo of human leukocyte antigen (HLA) molecules displayed on the cell surface. Successful recognition of HLA-bound non-self peptides can induce T cell responses leading to, for example, the destruction of infected cells. Today, largely due to advances in technology, we have an unprecedented capability to identify the nature of these presented peptides and unravel the true complexity of antigen presentation. Areas covered: In addition to conventional linear peptides, HLA molecules also present post-translationally modified sequences comprising a wealth of chemical and structural modifications, including a novel class of noncontiguous spliced peptides. This review focuses on these emerging themes in antigen presentation and how mass spectrometry in particular has contributed to a new view of the antigenic landscape that is presented to the immune system. Expert Commentary: Advances in the sensitivity of mass spectrometers and use of hybrid fragmentation technologies will provide more information-rich spectra of HLA bound peptides leading to more definitive identification of T cell epitopes. Coupled with improvements in sample preparation and new informatics workflows, studies will access novel classes of peptide antigen and allow interrogation of rare and clinically relevant samples.
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Affiliation(s)
- Sri H Ramarathinam
- a Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute , Monash University , Clayton , VIC , Australia
| | - Nathan P Croft
- a Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute , Monash University , Clayton , VIC , Australia
| | - Patricia T Illing
- a Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute , Monash University , Clayton , VIC , Australia
| | - Pouya Faridi
- a Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute , Monash University , Clayton , VIC , Australia
| | - Anthony W Purcell
- a Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute , Monash University , Clayton , VIC , Australia
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22
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Zhang L, Veith PD, Huq NL, Chen YY, Seers CA, Cross KJ, Gorasia DG, Reynolds EC. Porphyromonas gingivalis Gingipains Display Transpeptidation Activity. J Proteome Res 2018; 17:2803-2818. [PMID: 29984580 DOI: 10.1021/acs.jproteome.8b00286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Porphyromonas gingivalis is a keystone periodontal pathogen that has been associated with autoimmune disorders. The cell surface proteases Lys-gingipain (Kgp) and Arg-gingipains (RgpA and RgpB) are major virulence factors, and their proteolytic activity is enhanced by small peptides such as glycylglycine (GlyGly). The reaction kinetics suggested that GlyGly may function as an acceptor molecule for gingipain-catalyzed transpeptidation. Purified gingipains and P. gingivalis whole cells were used to digest selected substrates including human hemoglobin in the presence or absence of peptide acceptors. Mass spectrometric analysis of the substrates digested with gingipains in the presence of GlyGly showed that transpeptidation outcompeted hydrolysis, whereas the trypsin-digested controls exhibited predominantly hydrolysis activity. The transpeptidation levels increased with increasing concentration of GlyGly. Purified gingipains and whole cells exhibited extensive transpeptidation activities on human hemoglobin. All hemoglobin cleavage sites were found to be suitable for GlyGly transpeptidation, and this transpeptidation enhanced hemoglobin digestion. The transpeptidation products were often more abundant than the corresponding hydrolysis products. In the absence of GlyGly, hemoglobin peptides produced during digestion were utilized as acceptors leading to the detection of up to 116 different transpeptidation products in a single reaction. P. gingivalis cells were able to digest hemoglobin faster when acceptor peptides derived from human serum albumin were included in the reaction, suggesting that gingipain-catalyzed transpeptidation may be relevant for substrates encountered in vivo. The transpeptidation of host proteins in vivo may potentially lead to the breakdown of immunological tolerance, culminating in autoimmune reactions.
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Affiliation(s)
- Lianyi Zhang
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Paul D Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - N Laila Huq
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Yu-Yen Chen
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Christine A Seers
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Keith J Cross
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Dhana G Gorasia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
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23
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C-terminal modification of the insulin B:11-23 peptide creates superagonists in mouse and human type 1 diabetes. Proc Natl Acad Sci U S A 2017; 115:162-167. [PMID: 29255035 PMCID: PMC5776820 DOI: 10.1073/pnas.1716527115] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Insulin is a target of CD4 T cells in type 1 diabetes in mice and humans. Why the major epitope in the insulin B chain is presented poorly to the diabetogenic CD4 T cells by the disease-associated major histocompatibility class II (MHCII) alleles has been highly debated. Here we present high-resolution mouse and human MHCII structures and T-cell functional data to show that C-terminal modifications of this epitope are required for binding and presentation in the appropriate position in the MHCII binding groove. These results suggest that pancreas-specific posttranslational modifications of this peptide may play a role in the induction of diabetes and explain how the pathogenic T cells escape deletion in the thymus. A polymorphism at β57 in some major histocompatibility complex class II (MHCII) alleles of rodents and humans is associated with a high risk for developing type 1 diabetes (T1D). However, a highly diabetogenic insulin B chain epitope within the B:9–23 peptide is presented poorly by these alleles to a variety of mouse and human CD4 T cells isolated from either nonobese diabetic (NOD) mice or humans with T1D. We have shown for both species that mutations at the C-terminal end of this epitope dramatically improve presentation to these T cells. Here we present the crystal structures of these mutated peptides bound to mouse IAg7 and human HLA-DQ8 that show how the mutations function to improve T-cell activation. In both peptide binding grooves, the mutation of B:22R to E in the peptide changes a highly unfavorable side chain for the p9 pocket to an optimal one that is dependent on the β57 polymorphism, accounting for why these peptides bind much better to these MHCIIs. Furthermore, a second mutation of the adjacent B:21 (E to G) removes a side chain from the surface of the complex that is highly unfavorable for a subset of NOD mouse CD4 cells, thereby greatly enhancing their response to the complex. These results point out the similarities between the mouse and human responses to this B chain epitope in T1D and suggest there may be common posttranslational modifications at the C terminus of the peptide in vivo to create the pathogenic epitopes in both species.
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24
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Post-Translational Peptide Splicing and T Cell Responses. Trends Immunol 2017; 38:904-915. [PMID: 28830734 DOI: 10.1016/j.it.2017.07.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/10/2017] [Accepted: 07/26/2017] [Indexed: 12/21/2022]
Abstract
CD8+ T cell specificity depends on the recognition of MHC class I-epitope complexes at the cell surface. These epitopes are mainly produced via degradation of proteins by the proteasome, generating fragments of the original sequence. However, it is now clear that proteasomes can produce a significant portion of epitopes by reshuffling the antigen sequence, thus expanding the potential antigenic repertoire. MHC class I-restricted spliced epitopes have been described in tumors and infections, suggesting an unpredicted relevance of these peculiar peptides. We review current knowledge about proteasome-catalyzed peptide splicing (PCPS), the emerging rules governing this process, and the potential implications for our understanding and therapeutic use of CD8+ T cells, as well as mechanisms generating other non-canonical antigenic epitopes targeted by the T cell response.
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25
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Harbige J, Eichmann M, Peakman M. New insights into non-conventional epitopes as T cell targets: The missing link for breaking immune tolerance in autoimmune disease? J Autoimmun 2017; 84:12-20. [PMID: 28803690 DOI: 10.1016/j.jaut.2017.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/29/2017] [Accepted: 08/01/2017] [Indexed: 12/15/2022]
Abstract
The mechanism by which immune tolerance is breached in autoimmune disease is poorly understood. One possibility is that post-translational modification of self-antigens leads to peripheral recognition of neo-epitopes against which central and peripheral tolerance is inadequate. Accumulating evidence points to multiple mechanisms through which non-germline encoded sequences can give rise to these non-conventional epitopes which in turn engage the immune system as T cell targets. In particular, where these modifications alter the rules of epitope engagement with MHC molecules, such non-conventional epitopes offer a persuasive explanation for associations between specific HLA alleles and autoimmune diseases. In this review article, we discuss current understanding of mechanisms through which non-conventional epitopes may be generated, focusing on several recently described pathways that can transpose germline-encoded sequences. We contextualise these discoveries around type 1 diabetes, the prototypic organ-specific autoimmune disease in which specific HLA-DQ molecules confer high risk. Non-conventional epitopes have the potential to act as tolerance breakers or disease drivers in type 1 diabetes, prompting a timely re-evaluation of models of a etiopathogenesis. Future studies are required to elucidate the disease-relevance of a range of potential non-germline epitopes and their relationship to the natural peptide repertoire.
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Affiliation(s)
- James Harbige
- Department of Immunobiology, Faculty of Life Sciences & Medicine, King's College London, UK.
| | - Martin Eichmann
- Department of Immunobiology, Faculty of Life Sciences & Medicine, King's College London, UK
| | - Mark Peakman
- Department of Immunobiology, Faculty of Life Sciences & Medicine, King's College London, UK; Division of Diabetes and Nutritional Sciences, King's College London, UK; Institute of Diabetes, Endocrinology and Obesity, King's Health Partners, London, UK.
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26
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Proteasomes generate spliced epitopes by two different mechanisms and as efficiently as non-spliced epitopes. Sci Rep 2016; 6:24032. [PMID: 27049119 PMCID: PMC4822137 DOI: 10.1038/srep24032] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/15/2016] [Indexed: 12/24/2022] Open
Abstract
Proteasome-catalyzed peptide splicing represents an additional catalytic activity of proteasomes contributing to the pool of MHC-class I-presented epitopes. We here biochemically and functionally characterized a new melanoma gp100 derived spliced epitope. We demonstrate that the gp100mel47–52/40–42 antigenic peptide is generated in vitro and in cellulo by a not yet described proteasomal condensation reaction. gp100mel47–52/40–42 generation is enhanced in the presence of the β5i/LMP7 proteasome-subunit and elicits a peptide-specific CD8+ T cell response. Importantly, we demonstrate that different gp100mel-derived spliced epitopes are generated and presented to CD8+ T cells with efficacies comparable to non-spliced canonical tumor epitopes and that gp100mel-derived spliced epitopes trigger activation of CD8+ T cells found in peripheral blood of half of the melanoma patients tested. Our data suggest that both transpeptidation and condensation reactions contribute to the frequent generation of spliced epitopes also in vivo and that their immune relevance may be comparable to non-spliced epitopes.
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27
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Platteel ACM, Mishto M, Textoris-Taube K, Keller C, Liepe J, Busch DH, Kloetzel PM, Sijts AJAM. CD8(+) T cells of Listeria monocytogenes-infected mice recognize both linear and spliced proteasome products. Eur J Immunol 2016; 46:1109-18. [PMID: 26909514 DOI: 10.1002/eji.201545989] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 01/25/2016] [Accepted: 02/17/2016] [Indexed: 02/05/2023]
Abstract
CD8(+) T cells responding to infection recognize pathogen-derived epitopes presented by MHC class-I molecules. While most of such epitopes are generated by proteasome-mediated antigen cleavage, analysis of tumor antigen processing has revealed that epitopes may also derive from proteasome-catalyzed peptide splicing (PCPS). To determine whether PCPS contributes to epitope processing during infection, we analyzed the fragments produced by purified proteasomes from a Listeria monocytogenes polypeptide. Mass spectrometry identified a known H-2K(b) -presented linear epitope (LLO296-304 ) in the digests, as well as four spliced peptides that were trimmed by ERAP into peptides with in silico predicted H-2K(b) binding affinity. These spliced peptides, which displayed sequence similarity with LLO296-304 , bound to H-2K(b) molecules in cellular assays and one of the peptides was recognized by CD8(+) T cells of infected mice. This spliced epitope differed by one amino acid from LLO296-304 and double staining with LLO296-304 - and spliced peptide-folded MHC multimers showed that LLO296-304 and its spliced variant were recognized by the same CD8(+) T cells. Thus, PCPS multiplies the variety of peptides that is processed from an antigen and leads to the production of epitope variants that can be recognized by cross-reacting pathogen-specific CD8(+) T cells. Such mechanism may reduce the chances for pathogen immune evasion.
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Affiliation(s)
- Anouk C M Platteel
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Michele Mishto
- Institut für Biochemie, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Interdepartmental Centre "Luigi Galvani" for Bioinformatics, Biophysics and Biocomplexity (CIG), Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | | | - Christin Keller
- Institut für Biochemie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Juliane Liepe
- Centre for Integrative Systems Biology and Bioinformatics, Department of Life Sciences, Imperial College London, London, UK
| | - Dirk H Busch
- Institute for Medical Microbiology, Immunology and Hygiene, TU Munich, Munich, Germany
| | - Peter M Kloetzel
- Institut für Biochemie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Alice J A M Sijts
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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28
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Berkers CR, de Jong A, Schuurman KG, Linnemann C, Geenevasen JAJ, Schumacher TNM, Rodenko B, Ovaa H. Peptide Splicing in the Proteasome Creates a Novel Type of Antigen with an Isopeptide Linkage. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 195:4075-84. [PMID: 26401000 PMCID: PMC4642838 DOI: 10.4049/jimmunol.1402454] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 06/23/2015] [Indexed: 11/19/2022]
Abstract
The proteasome is able to create spliced Ags, in which two distant parts of a protein are excised and ligated together to form a novel peptide, for presentation by MHC class I molecules. These noncontiguous epitopes are generated via a transpeptidation reaction catalyzed by the proteasomal active sites. Transpeptidation reactions in the proteasome follow explicit rules and occur particularly efficiently when the C-terminal ligation partner contains a lysine or arginine residue at the site of ligation. Lysine contains two amino groups that theoretically may both participate in ligation reactions, implying that potentially not only peptide but also isopeptide linkages could be formed. Using nuclear magnetic resonance spectroscopy, we demonstrate in the present study that the proteasome can use the ε-amino group of an N-terminal lysine residue in transpeptidation reactions to create a novel type of posttranslationally modified epitopes. We show that the overall efficiency of ε ligation is only 10-fold lower as compared with α ligation, suggesting that the proteasome can produce sufficient isopeptide Ag to evoke a T cell response. Additionally, we show that isopeptides are more stable toward further proteasomal processing than are normal peptides, and we demonstrate that isopeptides can bind to HLA-A2.1 and HLA-A3 with high affinity. These properties likely increase the fraction of ε-ligated peptides presented on the cell surface for CD8(+) T cell surveillance. Finally, we show that isopeptide Ags are immunogenic in vivo. We postulate that ε ligation is a genuine posttranslational modification, suggesting that the proteasome can create a novel type of Ag that is likely to play a role in immunity.
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Affiliation(s)
- Celia R Berkers
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Annemieke de Jong
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Karianne G Schuurman
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Carsten Linnemann
- Division of Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and
| | - Jan A J Geenevasen
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Ton N M Schumacher
- Division of Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and
| | - Boris Rodenko
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands;
| | - Huib Ovaa
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands;
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29
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N-terminal additions to the WE14 peptide of chromogranin A create strong autoantigen agonists in type 1 diabetes. Proc Natl Acad Sci U S A 2015; 112:13318-23. [PMID: 26453556 DOI: 10.1073/pnas.1517862112] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Chromogranin A (ChgA) is an autoantigen for CD4(+) T cells in the nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D). The natural ChgA-processed peptide, WE14, is a weak agonist for the prototypical T cell, BDC-2.5, and other ChgA-specific T-cell clones. Mimotope peptides with much higher activity share a C-terminal motif, WXRM(D/E), that is predicted to lie in the p5 to p9 position in the mouse MHC class II, IA(g7) binding groove. This motif is also present in WE14 (WSRMD), but at its N terminus. Therefore, to place the WE14 motif into the same position as seen in the mimotopes, we added the amino acids RLGL to its N terminus. Like the other mimotopes, RLGL-WE14, is much more potent than WE14 in T-cell stimulation and activates a diverse population of CD4(+) T cells, which also respond to WE14 as well as islets from WT, but not ChgA(-/-) mice. The crystal structure of the IA(g7)-RLGL-WE14 complex confirmed the predicted placement of the peptide within the IA(g7) groove. Fluorescent IA(g7)-RLGL-WE14 tetramers bind to ChgA-specific T-cell clones and easily detect ChgA-specific T cells in the pancreas and pancreatic lymph nodes of NOD mice. The prediction that many different N-terminal amino acid extensions to the WXRM(D/E) motif are sufficient to greatly improve T-cell stimulation leads us to propose that such a posttranslational modification may occur uniquely in the pancreas or pancreatic lymph nodes, perhaps via the mechanism of transpeptidation. This modification could account for the escape of these T cells from thymic negative selection.
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30
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Berkers CR, de Jong A, Schuurman KG, Linnemann C, Meiring HD, Janssen L, Neefjes JJ, Schumacher TNM, Rodenko B, Ovaa H. Definition of Proteasomal Peptide Splicing Rules for High-Efficiency Spliced Peptide Presentation by MHC Class I Molecules. THE JOURNAL OF IMMUNOLOGY 2015; 195:4085-95. [PMID: 26401003 DOI: 10.4049/jimmunol.1402455] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 08/24/2015] [Indexed: 11/19/2022]
Abstract
Peptide splicing, in which two distant parts of a protein are excised and then ligated to form a novel peptide, can generate unique MHC class I-restricted responses. Because these peptides are not genetically encoded and the rules behind proteasomal splicing are unknown, it is difficult to predict these spliced Ags. In the current study, small libraries of short peptides were used to identify amino acid sequences that affect the efficiency of this transpeptidation process. We observed that splicing does not occur at random, neither in terms of the amino acid sequences nor through random splicing of peptides from different sources. In contrast, splicing followed distinct rules that we deduced and validated both in vitro and in cells. Peptide ligation was quantified using a model peptide and demonstrated to occur with up to 30% ligation efficiency in vitro, provided that optimal structural requirements for ligation were met by both ligating partners. In addition, many splicing products could be formed from a single protein. Our splicing rules will facilitate prediction and detection of new spliced Ags to expand the peptidome presented by MHC class I Ags.
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Affiliation(s)
- Celia R Berkers
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Annemieke de Jong
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Karianne G Schuurman
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Carsten Linnemann
- Division of Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and
| | - Hugo D Meiring
- Institute for Translational Vaccinology, 3721 MA Bilthoven, the Netherlands
| | - Lennert Janssen
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Jacques J Neefjes
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Ton N M Schumacher
- Division of Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands; and
| | - Boris Rodenko
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Huib Ovaa
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands;
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31
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N-lactoyl-amino acids are ubiquitous metabolites that originate from CNDP2-mediated reverse proteolysis of lactate and amino acids. Proc Natl Acad Sci U S A 2015; 112:6601-6. [PMID: 25964343 DOI: 10.1073/pnas.1424638112] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Despite technological advances in metabolomics, large parts of the human metabolome are still unexplored. In an untargeted metabolomics screen aiming to identify substrates of the orphan transporter ATP-binding cassette subfamily C member 5 (ABCC5), we identified a class of mammalian metabolites, N-lactoyl-amino acids. Using parallel protein fractionation in conjunction with shotgun proteomics on fractions containing N-lactoyl-Phe-forming activity, we unexpectedly found that a protease, cytosolic nonspecific dipeptidase 2 (CNDP2), catalyzes their formation. N-lactoyl-amino acids are ubiquitous pseudodipeptides of lactic acid and amino acids that are rapidly formed by reverse proteolysis, a process previously considered to be negligible in vivo. The plasma levels of these metabolites strongly correlate with plasma levels of lactate and amino acid, as shown by increased levels after physical exercise and in patients with phenylketonuria who suffer from elevated Phe levels. Our approach to identify unknown metabolites and their biosynthesis has general applicability in the further exploration of the human metabolome.
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32
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Chung MK, Grigoryan H, Iavarone AT, Rappaport SM. Antibody Enrichment and Mass Spectrometry of Albumin-Cys34 Adducts. Chem Res Toxicol 2013; 27:400-7. [DOI: 10.1021/tx400337k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ming-Kei Chung
- Center
for Exposure Biology, School of Public Health, University of California, Berkeley, California 94720, United States
| | - Hasmik Grigoryan
- Center
for Exposure Biology, School of Public Health, University of California, Berkeley, California 94720, United States
| | - Anthony T. Iavarone
- Department
of Chemistry and QB3 Institute, University of California, Berkeley, California 94720, United States
| | - Stephen M. Rappaport
- Center
for Exposure Biology, School of Public Health, University of California, Berkeley, California 94720, United States
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33
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Barber CJS, Pujara PT, Reed DW, Chiwocha S, Zhang H, Covello PS. The two-step biosynthesis of cyclic peptides from linear precursors in a member of the plant family Caryophyllaceae involves cyclization by a serine protease-like enzyme. J Biol Chem 2013; 288:12500-10. [PMID: 23486480 DOI: 10.1074/jbc.m112.437947] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Caryophyllaceae-type cyclic peptides (CPs) of 5-12 proteinogenic amino acids occur in 10 plant families. In Saponaria vaccaria (Caryophyllaceae), they have been shown to be formed from linear peptide precursors derived from ribosomal translation. There is also evidence for such precursors in other members of the Caryophyllaceae, Rutaceae, and Linaceae families. The biosynthesis of CP in the developing seeds of S. vaccaria was investigated with respect to the enzymes involved in precursor processing. Through biochemical assays with seed extracts and synthetic peptides, an enzyme named oligopeptidase 1 (OLP1) was found that catalyzes the cleavage of intermediates at the N terminus of the incipient CP. A second enzyme, peptide cyclase 1 (PCY1), which was separated chromatographically from OLP1, was found to act on the product of OLP1, giving rise to a cyclic peptide and concomitant removal of a C-terminal flanking sequence. PCY1 was partially purified, and using the methods of proteomics, a full-length cDNA clone encoding an enzyme matching the properties of PCY1 was obtained. The substrate specificity of purified recombinant PCY1, believed to be the first cloned plant enzyme whose function is peptide cyclization, was tested with synthetic peptides. The results are discussed in the light of CP biosynthetic systems of other organisms.
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Affiliation(s)
- Carla J S Barber
- National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada
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34
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Castangia R, Austeri M, Flitsch SL. Enzymatic Amine Acyl Exchange in Peptides on Gold Surfaces. Angew Chem Int Ed Engl 2012; 51:13016-8. [DOI: 10.1002/anie.201205404] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/30/2012] [Indexed: 11/09/2022]
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35
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Castangia R, Austeri M, Flitsch SL. Enzymatischer Amin-Acyl-Austausch in Peptiden auf Gold-Oberflächen. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201205404] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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36
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Mishto M, Goede A, Taube KT, Keller C, Janek K, Henklein P, Niewienda A, Kloss A, Gohlke S, Dahlmann B, Enenkel C, Kloetzel PM. Driving forces of proteasome-catalyzed peptide splicing in yeast and humans. Mol Cell Proteomics 2012; 11:1008-23. [PMID: 22822185 DOI: 10.1074/mcp.m112.020164] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteasome-catalyzed peptide splicing (PCPS) represents an additional activity of mammalian 20S proteasomes recently identified in connection with antigen presentation. We show here that PCPS is not restricted to mammalians but that it is also a feature of yeast 20S proteasomes catalyzed by all three active site β subunits. No major differences in splicing efficiency exist between human 20S standard- and immuno-proteasome or yeast 20S proteasome. Using H(2)(18)O to monitor the splicing reaction we also demonstrate that PCPS occurs via direct transpeptidation that slightly favors the generation of peptides spliced in cis over peptides spliced in trans. Splicing efficiency itself is shown to be controlled by proteasomal cleavage site preference as well as by the sequence characteristics of the spliced peptides. By use of kinetic data and quantitative analyses of PCPS obtained by mass spectrometry we developed a structural model with two PCPS binding sites in the neighborhood of the active Thr1.
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Affiliation(s)
- Michele Mishto
- Institut für Biochemie, Charité - Universitätsmedizin Berlin, Oudenarder Straβe 16, 13347 Berlin, Germany.
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37
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Hoppes R, Ekkebus R, Schumacher TN, Ovaa H. Technologies for MHC class I immunoproteomics. J Proteomics 2010; 73:1945-53. [DOI: 10.1016/j.jprot.2010.05.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 05/06/2010] [Accepted: 05/16/2010] [Indexed: 11/29/2022]
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38
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Liepe J, Mishto M, Textoris-Taube K, Janek K, Keller C, Henklein P, Kloetzel PM, Zaikin A. The 20S proteasome splicing activity discovered by SpliceMet. PLoS Comput Biol 2010; 6:e1000830. [PMID: 20613855 PMCID: PMC2891702 DOI: 10.1371/journal.pcbi.1000830] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 05/24/2010] [Indexed: 01/18/2023] Open
Abstract
The identification of proteasome-generated spliced peptides (PSP) revealed a new unpredicted activity of the major cellular protease. However, so far characterization of PSP was entirely dependent on the availability of patient-derived cytotoxic CD8+ T lymphocytes (CTL) thus preventing a systematic investigation of proteasome-catalyzed peptide splicing (PCPS). For an unrestricted PSP identification we here developed SpliceMet, combining the computer-based algorithm ProteaJ with in vitro proteasomal degradation assays and mass spectrometry. By applying SpliceMet for the analysis of proteasomal processing products of four different substrate polypeptides, derived from human tumor as well as viral antigens, we identified fifteen new spliced peptides generated by PCPS either by cis or from two separate substrate molecules, i.e., by trans splicing. Our data suggest that 20S proteasomes represent a molecular machine that, due to its catalytic and structural properties, facilitates the generation of spliced peptides, thereby providing a pool of qualitatively new peptides from which functionally relevant products may be selected.
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Affiliation(s)
- Juliane Liepe
- Institut für Biochemie, Charité, Universitätsmedizin Berlin, Berlin, Germany
- Centre for Bioinformatics, Division of Molecular Biosciences, Imperial College London, London, United Kingdom
| | - Michele Mishto
- Institut für Biochemie, Charité, Universitätsmedizin Berlin, Berlin, Germany
- Interdepartmental Center for Studies on Biophysics, Bioinformatics and Biocomplexity ‘L. Galvani’ (CIG), University of Bologna, Bologna, Italy
| | | | - Katharina Janek
- Institut für Biochemie, Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Christin Keller
- Institut für Biochemie, Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Petra Henklein
- Institut für Biochemie, Charité, Universitätsmedizin Berlin, Berlin, Germany
| | | | - Alexey Zaikin
- Institute for Women's Health and Department of Mathematics, University College London, London, United Kingdom
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39
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Dalet A, Vigneron N, Stroobant V, Hanada KI, Van den Eynde BJ. Splicing of Distant Peptide Fragments Occurs in the Proteasome by Transpeptidation and Produces the Spliced Antigenic Peptide Derived from Fibroblast Growth Factor-5. THE JOURNAL OF IMMUNOLOGY 2010; 184:3016-24. [DOI: 10.4049/jimmunol.0901277] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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