1
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Papadaki GF, Woodward CH, Young MC, Winters TJ, Burslem GM, Sgourakis NG. A Chicken Tapasin ortholog can chaperone empty HLA-B∗37:01 molecules independent of other peptide-loading components. J Biol Chem 2023; 299:105136. [PMID: 37543367 PMCID: PMC10534222 DOI: 10.1016/j.jbc.2023.105136] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/26/2023] [Accepted: 07/29/2023] [Indexed: 08/07/2023] Open
Abstract
Human Tapasin (hTapasin) is the main chaperone of MHC-I molecules, enabling peptide loading and antigen repertoire optimization across HLA allotypes. However, it is restricted to the endoplasmic reticulum (ER) lumen as part of the protein loading complex (PLC), and therefore is highly unstable when expressed in recombinant form. Additional stabilizing co-factors such as ERp57 are required to catalyze peptide exchange in vitro, limiting uses for the generation of pMHC-I molecules of desired antigen specificities. Here, we show that the chicken Tapasin (chTapasin) ortholog can be expressed recombinantly at high yields in a stable form, independent of co-chaperones. chTapasin can bind the human HLA-B∗37:01 with low micromolar-range affinity to form a stable tertiary complex. Biophysical characterization by methyl-based NMR methods reveals that chTapasin recognizes a conserved β2m epitope on HLA-B∗37:01, consistent with previously solved X-ray structures of hTapasin. Finally, we provide evidence that the B∗37:01/chTapasin complex is peptide-receptive and can be dissociated upon binding of high-affinity peptides. Our results highlight the use of chTapasin as a stable scaffold for protein engineering applications aiming to expand the ligand exchange function on human MHC-I and MHC-like molecules.
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Affiliation(s)
- Georgia F Papadaki
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Claire H Woodward
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael C Young
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Trenton J Winters
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - George M Burslem
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Cancer Biology and Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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2
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Temponeras I, Samiotaki M, Koumantou D, Nikopaschou M, Kuiper JJW, Panayotou G, Stratikos E. Distinct modulation of cellular immunopeptidome by the allosteric regulatory site of ER aminopeptidase 1. Eur J Immunol 2023; 53:e2350449. [PMID: 37134263 DOI: 10.1002/eji.202350449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/22/2023] [Accepted: 05/02/2023] [Indexed: 05/05/2023]
Abstract
ER aminopeptidase 1 (ERAP1) is an ER-resident aminopeptidase that excises N-terminal residues of peptides that then bind onto Major Histocompatibility Complex I molecules (MHC-I) and indirectly modulates adaptive immune responses. ERAP1 contains an allosteric regulatory site that accommodates the C-terminus of at least some peptide substrates, raising questions about its exact influence on antigen presentation and the potential of allosteric inhibition for cancer immunotherapy. We used an inhibitor that targets this regulatory site to study its effect on the immunopeptidome of a human cancer cell line. The immunopeptidomes of allosterically inhibited and ERAP1 KO cells contain high-affinity peptides with sequence motifs consistent with the cellular HLA class I haplotypes but are strikingly different in peptide composition. Compared to KO cells, allosteric inhibition did not affect the length distribution of peptides and skewed the peptide repertoire both in terms of sequence motifs and HLA allele utilization, indicating significant mechanistic differences between the two ways of disrupting ERAP1 function. These findings suggest that the regulatory site of ERAP1 plays distinct roles in antigenic peptide selection, which should be taken into consideration when designing therapeutic interventions targeting the cancer immunopeptidome.
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Affiliation(s)
- Ioannis Temponeras
- National Centre for Scientific Research Demokritos, Agia Paraskevi, Greece
- Department of Pharmacy, University of Patras, Patra, Greece
| | - Martina Samiotaki
- Biomedical Sciences Research Center "Alexander Fleming,", Institute for Bioinnovation, Vari, Greece
| | - Despoina Koumantou
- National Centre for Scientific Research Demokritos, Agia Paraskevi, Greece
| | - Martha Nikopaschou
- National Centre for Scientific Research Demokritos, Agia Paraskevi, Greece
- Department of Chemistry, National and Kapodistrian University of Athens, Zografou, Greece
| | - Jonas J W Kuiper
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - George Panayotou
- Biomedical Sciences Research Center "Alexander Fleming,", Institute for Bioinnovation, Vari, Greece
| | - Efstratios Stratikos
- National Centre for Scientific Research Demokritos, Agia Paraskevi, Greece
- Department of Chemistry, National and Kapodistrian University of Athens, Zografou, Greece
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3
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Wong-Benito V, de Rijke J, Dixon B. Antigen presentation in vertebrates: Structural and functional aspects. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 144:104702. [PMID: 37116963 DOI: 10.1016/j.dci.2023.104702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 03/20/2023] [Accepted: 03/29/2023] [Indexed: 06/05/2023]
Abstract
Antigen presentation is a key process of the immune system and is responsible for the activation of T cells. The main characters are the major histocompatibility complex class I (MHC-I) and class II (MHC-II) molecules, and accessory proteins that act as chaperones for these glycoproteins. Current knowledge of this process and also the elucidation of the structural features of these proteins, has been extensively reviewed in humans. Unfortunately, this is not the case for non-human species, wherein the function and structural characteristic of the antigen presentation proteins is far from being understood. The majority of previous studies in non-human species, especially in teleost fish and lower vertebrates, are limited to the transcriptomic level, which leads to gaps in the knowledge about the functional process of antigen presentation in these species. This review summarizes what is known so far about antigen presentation pathways in vertebrates from a structural and functional perspective. The focus is not only on the MHC receptors, but also, on the forgotten characters of these pathways such as the proteins of the peptide loading complex, and the MHC-II chaperone invariant chain.
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Affiliation(s)
| | - Jill de Rijke
- Department of Biology, University of Waterloo, Canada
| | - Brian Dixon
- Department of Biology, University of Waterloo, Canada.
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4
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Papadaki GF, Woodward CH, Young MC, Winters TJ, Burslem GM, Sgourakis NG. A Chicken Tapasin ortholog can chaperone empty HLA molecules independently of other peptide-loading components. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.23.546255. [PMID: 37425753 PMCID: PMC10326978 DOI: 10.1101/2023.06.23.546255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Human Tapasin (hTapasin) is the main chaperone of MHC-I molecules, enabling peptide loading and antigen repertoire optimization across HLA allotypes. However, it is restricted to the endoplasmic reticulum (ER) lumen as part of the protein loading complex (PLC) and therefore is highly unstable when expressed in recombinant form. Additional stabilizing co-factors such as ERp57 are required to catalyze peptide exchange in vitro , limiting uses for the generation of pMHC-I molecules of desired antigen specificities. Here, we show that the chicken Tapasin (chTapasin) ortholog can be expressed recombinantly at high yields in stable form, independently of co-chaperones. chTapasin can bind the human HLA-B * 37:01 with low micromolar-range affinity to form a stable tertiary complex. Biophysical characterization by methyl-based NMR methods reveals that chTapasin recognizes a conserved β 2 m epitope on HLA-B * 37:01, consistent with previously solved X-ray structures of hTapasin. Finally, we provide evidence that the B * 37:01/chTapasin complex is peptide-receptive and can be dissociated upon binding of high-affinity peptides. Our results highlight the use of chTapasin as a stable scaffold for future protein engineering applications aiming to expand the ligand exchange function on human MHC-I and MHC-like molecules.
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5
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Kuiper JJ, Prinz JC, Stratikos E, Kuśnierczyk P, Arakawa A, Springer S, Mintoff D, Padjen I, Shumnalieva R, Vural S, Kötter I, van de Sande MG, Boyvat A, de Boer JH, Bertsias G, de Vries N, Krieckaert CL, Leal I, Vidovič Valentinčič N, Tugal-Tutkun I, El Khaldi Ahanach H, Costantino F, Glatigny S, Mrazovac Zimak D, Lötscher F, Kerstens FG, Bakula M, Viera Sousa E, Böhm P, Bosman K, Kenna TJ, Powis SJ, Breban M, Gul A, Bowes J, Lories RJ, Nowatzky J, Wolbink GJ, McGonagle DG, Turkstra F. EULAR study group on ‘MHC-I-opathy’: identifying disease-overarching mechanisms across disciplines and borders. Ann Rheum Dis 2023:ard-2022-222852. [PMID: 36987655 DOI: 10.1136/ard-2022-222852] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 01/25/2023] [Indexed: 03/29/2023]
Abstract
The ‘MHC-I (major histocompatibility complex class I)-opathy’ concept describes a family of inflammatory conditions with overlapping clinical manifestations and a strong genetic link to the MHC-I antigen presentation pathway. Classical MHC-I-opathies such as spondyloarthritis, Behçet’s disease, psoriasis and birdshot uveitis are widely recognised for their strong association with certain MHC-I alleles and gene variants of the antigen processing aminopeptidases ERAP1 and ERAP2 that implicates altered MHC-I peptide presentation to CD8+T cells in the pathogenesis. Progress in understanding the cause and treatment of these disorders is hampered by patient phenotypic heterogeneity and lack of systematic investigation of the MHC-I pathway.Here, we discuss new insights into the biology of MHC-I-opathies that strongly advocate for disease-overarching and integrated molecular and clinical investigation to decipher underlying disease mechanisms. Because this requires transformative multidisciplinary collaboration, we introduce the EULAR study group on MHC-I-opathies to unite clinical expertise in rheumatology, dermatology and ophthalmology, with fundamental and translational researchers from multiple disciplines such as immunology, genomics and proteomics, alongside patient partners. We prioritise standardisation of disease phenotypes and scientific nomenclature and propose interdisciplinary genetic and translational studies to exploit emerging therapeutic strategies to understand MHC-I-mediated disease mechanisms. These collaborative efforts are required to address outstanding questions in the etiopathogenesis of MHC-I-opathies towards improving patient treatment and prognostication.
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Affiliation(s)
- Jonas Jw Kuiper
- Department of Ophthalmology, Center for Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Jörg C Prinz
- University Hospital, department of Dermatology and Allergy, Ludwig Maximilians University Munich, Munchen, Germany
| | - Efstratios Stratikos
- Laboratory of Biochemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Piotr Kuśnierczyk
- Laboratory of Immunogenetics and Tissue Immunology, Institute of Immunology and Experimental Therapy Ludwik Hirszfeld Polish Academy of Sciences, Wroclaw, Poland
| | - Akiko Arakawa
- University Hospital, department of Dermatology and Allergy, Ludwig Maximilians University Munich, Munchen, Germany
| | | | - Dillon Mintoff
- Department of Dermatology, Mater Dei Hospital, Msida, Malta
- Department of Pathology, University of Malta Faculty of Medicine and Surgery, Msida, Malta
| | - Ivan Padjen
- Division of Clinical Immunology and Rheumatology, University Hospital Centre Zagreb Department of Internal Medicine, Zagreb, Croatia
- University of Zagreb School of Medicine, Zagreb, Croatia
| | - Russka Shumnalieva
- Clinic of Rheumatology, Department of Rheumatology, Medical University of Sofia, Sofia, Bulgaria
| | - Seçil Vural
- School of Medicine, Department of Dermatology, Koç University, Istanbul, Turkey
| | - Ina Kötter
- Clinic for Rheumatology and Immunology, Bad Bramdsted Hospital, Bad Bramstedt, Germany
- Division of Rheumatology and Systemic Inflammatory Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marleen G van de Sande
- University of Amsterdam, Department of Rheumatology & Clinical Immunology and Department of Experimental Immunology, Amsterdam Institute for Infection & Immunity, Amsterdam UMC Location AMC, Amsterdam, The Netherlands
- Amsterdam Rheumatology and Immunology Center (ARC) | Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Ayşe Boyvat
- Department of Dermatology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Joke H de Boer
- Department of Ophthalmology, Center for Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - George Bertsias
- Department of Rheumatology and Clinical Immunology, University of Crete School of Medicine, Iraklio, Greece
- Laboratory of Autoimmunity-Inflammation, Institute of Molecular Biology and Biotechnology, Heraklion, Greece
| | - Niek de Vries
- University of Amsterdam, Department of Rheumatology & Clinical Immunology and Department of Experimental Immunology, Amsterdam Institute for Infection & Immunity, Amsterdam UMC Location AMC, Amsterdam, The Netherlands
- Amsterdam Rheumatology and Immunology Center (ARC) | Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Charlotte Lm Krieckaert
- Amsterdam Rheumatology and immunology Center (ARC)| Reade, Amsterdam, The Netherlands
- Department of Rheumatology, Reade Hoofdlocatie Dr Jan van Breemenstraat, Amsterdam, The Netherlands
| | - Inês Leal
- Department of Ophthalmology, Hospital de Santa Maria, Centro Hospitalar Universitário Lisboa Norte EPE, Lisboa, Portugal
- Centro de Estudeos das Ciencias da Visão, Universidade de Lisboa Faculdade de Medicina, Lisboa, Portugal
| | - Nataša Vidovič Valentinčič
- University Eye Clinic, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Ilknur Tugal-Tutkun
- Department of Ophthalmology, Istanbul University Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Hanane El Khaldi Ahanach
- Departement of Ophthalmology, Amsterdam UMC Location AMC, Amsterdam, The Netherlands
- Department of Ophthalmology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands
| | - Félicie Costantino
- Service de Rheumatology, Hospital Ambroise-Pare, Boulogne-Billancourt, France
- Infection & Inflammation, UMR 1173, Inserm, UVSQ, University Paris-Saclay, Montigny-le-Bretonneux, France
| | - Simon Glatigny
- Infection & Inflammation, UMR 1173, Inserm, UVSQ/Université Paris Saclay, Montigny-le-Bretonneux, France
- Laboratoire d'Excellence Inflamex, Paris, France
| | | | - Fabian Lötscher
- Department of Rheumatology and Immunology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
| | - Floor G Kerstens
- Amsterdam Rheumatology and immunology Center (ARC)| Reade, Amsterdam, The Netherlands
- Department of Rheumatology, Reade Hoofdlocatie Dr Jan van Breemenstraat, Amsterdam, The Netherlands
| | - Marija Bakula
- Division of Clinical Immunology and Rheumatology, University Hospital Centre Zagreb Department of Internal Medicine, Zagreb, Croatia
| | - Elsa Viera Sousa
- Rheumatology Research Unit Molecular João Lobo Antunes, University of Lisbon Medical Faculty, Lisboa, Portugal
- Rheumatology DepartmentSanta Maria Centro Hospital, Academic Medical Centre of Lisbon, Lisboa, Portugal
| | - Peter Böhm
- Patientpartner, German League against Rheumatism, Bonn, Germany
| | - Kees Bosman
- Patientpartner, Nationale Vereniging ReumaZorg, Nijmegen, The Netherlands
| | - Tony J Kenna
- Translational Research Institute, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Simon J Powis
- School of Medicine, University of St Andrews School of Medicine, St Andrews, UK
| | - Maxime Breban
- Service de Rheumatology, Hospital Ambroise-Pare, Boulogne-Billancourt, France
- Infection & Inflammation, UMR 1173, Inserm, UVSQ, University Paris-Saclay, Montigny-le-Bretonneux, France
| | - Ahmet Gul
- Division of Rheumatology, Istanbul University Istanbul Faculty of Medicine, Istanbul, Turkey
| | - John Bowes
- Centre for Genetics and Genomics Versus Arthritis, Centre for Musculoskeletal Research, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Center, The University of Manchester, Manchester, UK
- NIHR Manchester Musculoskeletal Biomedical Research Unit, Manchester University NHS Foundation Trust, Manchester, UK
| | - Rik Ju Lories
- Department of Rheumatology, KU Leuven University Hospitals Leuven, Leuven, Belgium
- Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Johannes Nowatzky
- Department of Medicine, Division of Rheumatology, NYU Langone Behçet's Disease Program, NYU Langone Ocular Rheumatology Program, New York University Grossman School of Medicine, New York University, New York, New York, USA
- Department of Pathology, New York University Grossman School of Medicine, New York, New York, USA
| | - Gerrit Jan Wolbink
- Amsterdam Rheumatology and immunology Center (ARC)| Reade, Amsterdam, The Netherlands
- Department Immunopathology, Sanquin Research, Amsterdam, The Netherlands
| | - Dennis G McGonagle
- Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, UK
- NIHR Leeds Biomedical Research Centre, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Franktien Turkstra
- Amsterdam Rheumatology and immunology Center (ARC)| Reade, Amsterdam, The Netherlands
- Department of Rheumatology, Reade Hoofdlocatie Dr Jan van Breemenstraat, Amsterdam, The Netherlands
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6
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Mavridis G, Mpakali A, Zoidakis J, Makridakis M, Vlahou A, Kaloumenou E, Ziotopoulou A, Georgiadis D, Papakyriakou A, Stratikos E. The ERAP1 active site cannot productively access the N-terminus of antigenic peptide precursors stably bound onto MHC class I. Sci Rep 2021; 11:16475. [PMID: 34389743 PMCID: PMC8363620 DOI: 10.1038/s41598-021-95786-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 07/22/2021] [Indexed: 12/01/2022] Open
Abstract
Processing of N-terminally elongated antigenic peptide precursors by Endoplasmic Reticulum Aminopeptidase 1 (ERAP1) is a key step in antigen presentation and the adaptive immune response. Although ERAP1 can efficiently process long peptides in solution, it has been proposed that it can also process peptides bound onto Major Histocompatibility Complex I molecules (MHCI). In a previous study, we suggested that the occasionally observed “ontο MHCI” trimming by ERAP1 is likely due to fast peptide dissociation followed by solution trimming, rather than direct action of ERAP1 onto the MHCI complex. However, other groups have proposed that ERAP1 can trim peptides covalently bound onto MHCI, which would preclude peptide dissociation. To explore this interaction, we constructed disulfide-linked MHCI-peptide complexes using HLA-B*08 and a 12mer kinetically labile peptide, or a 16mer carrying a phosphinic transition-state analogue N-terminus with high-affinity for ERAP1. Kinetic and biochemical analyses suggested that while both peptides could access the ERAP1 active site when free in solution, they were unable to do so when tethered in the MHCI binding groove. Our results suggest that MHCI binding protects, rather than promotes, antigenic peptide precursor trimming by ERAP1 and thus solution trimming is the more likely model of antigenic peptide processing.
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Affiliation(s)
- George Mavridis
- Protein Chemistry Laboratory, National Centre for Scientific Research Demokritos, 15341, Agia Paraskevi, Greece
| | - Anastasia Mpakali
- Protein Chemistry Laboratory, National Centre for Scientific Research Demokritos, 15341, Agia Paraskevi, Greece
| | - Jerome Zoidakis
- Centre of Basic Research, Biomedical Research Foundation of the Academy of Athens, 11527, Athens, Greece
| | - Manousos Makridakis
- Centre of Basic Research, Biomedical Research Foundation of the Academy of Athens, 11527, Athens, Greece
| | - Antonia Vlahou
- Centre of Basic Research, Biomedical Research Foundation of the Academy of Athens, 11527, Athens, Greece
| | - Eleni Kaloumenou
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15784, Panepistimiopolis Zografou, Greece
| | - Angeliki Ziotopoulou
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15784, Panepistimiopolis Zografou, Greece
| | - Dimitris Georgiadis
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15784, Panepistimiopolis Zografou, Greece
| | - Athanasios Papakyriakou
- Protein Chemistry Laboratory, National Centre for Scientific Research Demokritos, 15341, Agia Paraskevi, Greece
| | - Efstratios Stratikos
- Protein Chemistry Laboratory, National Centre for Scientific Research Demokritos, 15341, Agia Paraskevi, Greece. .,Biochemistry Laboratory, National and Kapodistrian University of Athens, 15784, Panepistimiopolis Zografou, Greece.
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7
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Colbert JD, Rock KL. How a tailor achieves the perfect fit. J Biol Chem 2020; 295:7211-7212. [PMID: 32444419 DOI: 10.1074/jbc.h120.013868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most antigenic peptides that bind stably to a major histocompatibility complex (MHC) I molecule for display to the immune system are approximately the same length, thanks in part to the expert trimming done by endoplasmic reticulum aminopeptidases (ERAPs), the final peptidases in the antigen-presentation pathway. An open question is whether ERAPs edit peptides to this optimal length while they are bound to MHC I molecules (using the latter as a pattern of sorts) or by free hand. Mavridis et al. present multiple lines of evidence that this trimming cannot readily occur on MHC I molecules, but rather only in solution, suggesting that ERAPs work alone to tailor the perfect fit for the immunopeptidome.
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Affiliation(s)
- Jeff D Colbert
- Department of Pathology, University of Massachusetts, Worcester, Massachusetts 01655
| | - Kenneth L Rock
- Department of Pathology, University of Massachusetts, Worcester, Massachusetts 01655.
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8
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Mavridis G, Arya R, Domnick A, Zoidakis J, Makridakis M, Vlahou A, Mpakali A, Lelis A, Georgiadis D, Tampé R, Papakyriakou A, Stern LJ, Stratikos E. A systematic re-examination of processing of MHCI-bound antigenic peptide precursors by endoplasmic reticulum aminopeptidase 1. J Biol Chem 2020; 295:7193-7210. [PMID: 32184355 PMCID: PMC7247305 DOI: 10.1074/jbc.ra120.012976] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 03/09/2020] [Indexed: 11/06/2022] Open
Abstract
Endoplasmic reticulum aminopeptidase 1 (ERAP1) trims antigenic peptide precursors to generate mature antigenic peptides for presentation by major histocompatibility complex class I (MHCI) molecules and regulates adaptive immune responses. ERAP1 has been proposed to trim peptide precursors both in solution and in preformed MHCI-peptide complexes, but which mode is more relevant to its biological function remains controversial. Here, we compared ERAP1-mediated trimming of antigenic peptide precursors in solution or when bound to three MHCI alleles, HLA-B*58, HLA-B*08, and HLA-A*02. For all MHCI-peptide combinations, peptide binding onto MHCI protected against ERAP1-mediated trimming. In only a single MHCI-peptide combination, trimming of an HLA-B*08-bound 12-mer progressed at a considerable rate, albeit still slower than in solution. Results from thermodynamic, kinetic, and computational analyses suggested that this 12-mer is highly labile and that apparent on-MHC trimming rates are always slower than that of MHCI-peptide dissociation. Both ERAP2 and leucine aminopeptidase, an enzyme unrelated to antigen processing, could trim this labile peptide from preformed MHCI complexes as efficiently as ERAP1. A pseudopeptide analogue with high affinity for both HLA-B*08 and the ERAP1 active site could not promote the formation of a ternary ERAP1/MHCI/peptide complex. Similarly, no interactions between ERAP1 and purified peptide-loading complex were detected in the absence or presence of a pseudopeptide trap. We conclude that MHCI binding protects peptides from ERAP1 degradation and that trimming in solution along with the dynamic nature of peptide binding to MHCI are sufficient to explain ERAP1 processing of antigenic peptide precursors.
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Affiliation(s)
- George Mavridis
- National Centre for Scientific Research Demokritos, Agia Paraskevi 15341, Greece
| | - Richa Arya
- University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Alexander Domnick
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt/Main, Germany
| | - Jerome Zoidakis
- Centre of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece
| | - Manousos Makridakis
- Centre of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece
| | - Antonia Vlahou
- Centre of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece
| | - Anastasia Mpakali
- National Centre for Scientific Research Demokritos, Agia Paraskevi 15341, Greece
| | - Angelos Lelis
- Laboratory of Organic Chemistry, Chemistry Department, University of Athens, Athens 15772, Greece
| | - Dimitris Georgiadis
- Laboratory of Organic Chemistry, Chemistry Department, University of Athens, Athens 15772, Greece
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt/Main, Germany
| | | | - Lawrence J Stern
- University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Efstratios Stratikos
- National Centre for Scientific Research Demokritos, Agia Paraskevi 15341, Greece.
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9
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Liddle J, Hutchinson JP, Kitchen S, Rowland P, Neu M, Cecconie T, Holmes DS, Jones E, Korczynska J, Koumantou D, Lea JD, Nickels L, Pemberton M, Phillipou A, Schneck JL, Sheehan H, Tinworth CP, Uings I, Wojno-Picon J, Young RJ, Stratikos E. Targeting the Regulatory Site of ER Aminopeptidase 1 Leads to the Discovery of a Natural Product Modulator of Antigen Presentation. J Med Chem 2020; 63:3348-3358. [PMID: 32109056 DOI: 10.1021/acs.jmedchem.9b02123] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
ER aminopeptidase 1 (ERAP1) is an intracellular enzyme that generates antigenic peptides and is an emerging target for cancer immunotherapy and the control of autoimmunity. ERAP1 inhibitors described previously target the active site and are limited in selectivity, minimizing their clinical potential. To address this, we targeted the regulatory site of ERAP1 using a high-throughput screen and discovered a small molecule hit that is highly selective for ERAP1. (4aR,5S,6R,8S,8aR)-5-(2-(Furan-3-yl)ethyl)-8-hydroxy-5,6,8a-trimethyl-3,4,4a,5,6,7,8,8a-octahydronaphthalene-1-carboxylic acid is a natural product found in Dodonaea viscosa that constitutes a submicromolar, highly selective, and cell-active modulator of ERAP1. Although the compound activates hydrolysis of small model substrates, it is a competitive inhibitor for physiologically relevant longer peptides. Crystallographic analysis confirmed that the compound targets the regulatory site of the enzyme that normally binds the C-terminus of the peptide substrate. Our findings constitute a novel starting point for the development of selective ERAP1 modulators that have potential for further clinical development.
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Affiliation(s)
- John Liddle
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Jonathan P Hutchinson
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Semra Kitchen
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Paul Rowland
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Margarete Neu
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Ted Cecconie
- Medicinal Science and Technology, GlaxoSmithKline, Collegeville, Pennsylvania 19426, United States
| | - Duncan S Holmes
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Emma Jones
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Justyna Korczynska
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Despoina Koumantou
- National Centre for Scientific Research "Demokritos", Patriarchou Gregoriou and Neapoleos 27, Agia Paraskevi, Athens 15341, Greece
| | - Jonathan D Lea
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Leng Nickels
- Medicinal Science and Technology, GlaxoSmithKline, Collegeville, Pennsylvania 19426, United States
| | - Michelle Pemberton
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Alex Phillipou
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Jessica L Schneck
- Medicinal Science and Technology, GlaxoSmithKline, Collegeville, Pennsylvania 19426, United States
| | - Hester Sheehan
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Christopher P Tinworth
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Iain Uings
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Justyna Wojno-Picon
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Robert J Young
- Medicinal Science and Technology, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Efstratios Stratikos
- National Centre for Scientific Research "Demokritos", Patriarchou Gregoriou and Neapoleos 27, Agia Paraskevi, Athens 15341, Greece
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10
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Mechanism for antigenic peptide selection by endoplasmic reticulum aminopeptidase 1. Proc Natl Acad Sci U S A 2019; 116:26709-26716. [PMID: 31843903 DOI: 10.1073/pnas.1912070116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Endoplasmic reticulum aminopeptidase 1 (ERAP1) is an intracellular enzyme that optimizes the peptide cargo of major histocompatibility class I (MHC-I) molecules and regulates adaptive immunity. It has unusual substrate selectivity for length and sequence, resulting in poorly understood effects on the cellular immunopeptidome. To understand substrate selection by ERAP1, we solved 2 crystal structures of the enzyme with bound transition-state pseudopeptide analogs at 1.68 Å and 1.72 Å. Both peptides have their N terminus bound at the active site and extend away along a large internal cavity, interacting with shallow pockets that can influence selectivity. The longer peptide is disordered through the central region of the cavity and has its C terminus bound in an allosteric pocket of domain IV that features a carboxypeptidase-like structural motif. These structures, along with enzymatic and computational analyses, explain how ERAP1 can select peptides based on length while retaining the broad sequence-specificity necessary for its biological function.
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11
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Textoris-Taube K, Cammann C, Henklein P, Topfstedt E, Ebstein F, Henze S, Liepe J, Zhao F, Schadendorf D, Dahlmann B, Uckert W, Paschen A, Mishto M, Seifert U. ER-aminopeptidase 1 determines the processing and presentation of an immunotherapy-relevant melanoma epitope. Eur J Immunol 2019; 50:270-283. [PMID: 31729751 DOI: 10.1002/eji.201948116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 08/19/2019] [Accepted: 11/13/2019] [Indexed: 01/01/2023]
Abstract
Dissecting the different steps of the processing and presentation of tumor-associated antigens is a key aspect of immunotherapies enabling to tackle the immune response evasion attempts of cancer cells. The immunodominant glycoprotein gp100209-217 epitope, which is liberated from the melanoma differentiation antigen gp100PMEL17 , is part of immunotherapy trials. By analyzing different human melanoma cell lines, we here demonstrate that a pool of N-terminal extended peptides sharing the common minimal epitope is generated by melanoma proteasome subtypes. In vitro and in cellulo experiments indicate that ER-resident aminopeptidase 1 (ERAP1)-but not ERAP2-defines the processing of this peptide pool thereby modulating the T-cell recognition of melanoma cells. By combining the outcomes of our studies and others, we can sketch the complex processing and endogenous presentation pathway of the gp100209-217 -containing epitope/peptides, which are produced by proteasomes and are translocated to the vesicular compartment through different pathways, where the precursor peptides that reach the endoplasmic reticulum are further processed by ERAP1. The latter step enhances the activation of epitope-specific T lymphocytes, which might be a target to improve the efficiency of anti-melanoma immunotherapy.
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Affiliation(s)
- Kathrin Textoris-Taube
- Shared Facility for Mass Spectrometry, Berlin Institute of Health, Institut für Biochemie, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Clemens Cammann
- Friedrich Loeffler Institut für Medizinische Mikrobiologie-Virologie, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Petra Henklein
- Berlin Institute of Health, Institut für Biochemie, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Eylin Topfstedt
- Friedrich Loeffler Institut für Medizinische Mikrobiologie-Virologie, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Frédéric Ebstein
- Berlin Institute of Health, Institut für Biochemie, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sarah Henze
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Juliane Liepe
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Fang Zhao
- Klinik für Dermatologie, Universitätsklinikum Essen, Essen and German Cancer Consortium (DKTK), Universität Duisburg-Essen, Essen, Germany
| | - Dirk Schadendorf
- Klinik für Dermatologie, Universitätsklinikum Essen, Essen and German Cancer Consortium (DKTK), Universität Duisburg-Essen, Essen, Germany
| | - Burkhardt Dahlmann
- Berlin Institute of Health, Institut für Biochemie, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Wolfgang Uckert
- Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz Gemeinschaft, Berlin, Germany
| | - Annette Paschen
- Klinik für Dermatologie, Universitätsklinikum Essen, Essen and German Cancer Consortium (DKTK), Universität Duisburg-Essen, Essen, Germany
| | - Michele Mishto
- Centre for Inflammation Biology and Cancer Immunology (CIBCI) & Peter Gorer Department of Immunobiology, King's College London, London, United Kingdom.,Centro Interdipartimentale di Ricerca sul Cancro "Giorgio Prodi", University of Bologna, Bologna, Italy
| | - Ulrike Seifert
- Friedrich Loeffler Institut für Medizinische Mikrobiologie-Virologie, Universitätsmedizin Greifswald, Greifswald, Germany
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12
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Koumantou D, Barnea E, Martin-Esteban A, Maben Z, Papakyriakou A, Mpakali A, Kokkala P, Pratsinis H, Georgiadis D, Stern LJ, Admon A, Stratikos E. Editing the immunopeptidome of melanoma cells using a potent inhibitor of endoplasmic reticulum aminopeptidase 1 (ERAP1). Cancer Immunol Immunother 2019; 68:1245-1261. [PMID: 31222486 PMCID: PMC6684451 DOI: 10.1007/s00262-019-02358-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/11/2019] [Indexed: 12/19/2022]
Abstract
The efficacy of cancer immunotherapy, including treatment with immune-checkpoint inhibitors, often is limited by ineffective presentation of antigenic peptides that elicit T-cell-mediated anti-tumor cytotoxic responses. Manipulation of antigen presentation pathways is an emerging approach for enhancing the immunogenicity of tumors in immunotherapy settings. ER aminopeptidase 1 (ERAP1) is an intracellular enzyme that trims peptides as part of the system that generates peptides for binding to MHC class I molecules (MHC-I). We hypothesized that pharmacological inhibition of ERAP1 in cells could regulate the cellular immunopeptidome. To test this hypothesis, we treated A375 melanoma cells with a recently developed potent ERAP1 inhibitor and analyzed the presented MHC-I peptide repertoire by isolating MHC-I, eluting bound peptides, and identifying them using capillary chromatography and tandem mass spectrometry (LC-MS/MS). Although the inhibitor did not reduce cell-surface MHC-I expression, it induced qualitative and quantitative changes in the presented peptidomes. Specifically, inhibitor treatment altered presentation of about half of the total 3204 identified peptides, including about one third of the peptides predicted to bind tightly to MHC-I. Inhibitor treatment altered the length distribution of eluted peptides without change in the basic binding motifs. Surprisingly, inhibitor treatment enhanced the average predicted MHC-I binding affinity, by reducing presentation of sub-optimal long peptides and increasing presentation of many high-affinity 9-12mers, suggesting that baseline ERAP1 activity in this cell line is destructive for many potential epitopes. Our results suggest that chemical inhibition of ERAP1 may be a viable approach for manipulating the immunopeptidome of cancer.
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MESH Headings
- Aminopeptidases/antagonists & inhibitors
- Aminopeptidases/metabolism
- Antigen Presentation
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/immunology
- Antigens, Neoplasm/metabolism
- Antineoplastic Agents/pharmacology
- Cancer Vaccines/immunology
- Cell Line, Tumor
- Cytotoxicity, Immunologic
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- HLA Antigens/metabolism
- Histocompatibility Antigens Class I/metabolism
- Humans
- Immunogenicity, Vaccine
- Immunotherapy/methods
- Lymphocyte Activation
- Melanoma/drug therapy
- Minor Histocompatibility Antigens/metabolism
- Molecular Targeted Therapy
- Peptides/genetics
- Peptides/immunology
- Peptides/metabolism
- Protease Inhibitors/pharmacology
- Protein Binding
- T-Lymphocytes, Cytotoxic/immunology
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Affiliation(s)
- Despoina Koumantou
- National Centre for Scientific Research Demokritos, Patriarchou Gregoriou and Neapoleos 27, Agia Paraskevi, 15341, Athens, Greece
| | - Eilon Barnea
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Adrian Martin-Esteban
- Centro de Biologia Molecular Severo Ochoa (Consejo Superior de Investigaciones Cientificas, Universidad Autonoma), Madrid, Spain
| | - Zachary Maben
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Athanasios Papakyriakou
- National Centre for Scientific Research Demokritos, Patriarchou Gregoriou and Neapoleos 27, Agia Paraskevi, 15341, Athens, Greece
| | - Anastasia Mpakali
- National Centre for Scientific Research Demokritos, Patriarchou Gregoriou and Neapoleos 27, Agia Paraskevi, 15341, Athens, Greece
| | - Paraskevi Kokkala
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Harris Pratsinis
- National Centre for Scientific Research Demokritos, Patriarchou Gregoriou and Neapoleos 27, Agia Paraskevi, 15341, Athens, Greece
| | - Dimitris Georgiadis
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Lawrence J Stern
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Arie Admon
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Efstratios Stratikos
- National Centre for Scientific Research Demokritos, Patriarchou Gregoriou and Neapoleos 27, Agia Paraskevi, 15341, Athens, Greece.
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13
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ERAP1 shapes just part of the immunopeptidome. Hum Immunol 2019; 80:296-301. [DOI: 10.1016/j.humimm.2019.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/04/2019] [Accepted: 03/04/2019] [Indexed: 01/22/2023]
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14
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Kuśnierczyk P, Stratikos E. Endoplasmic reticulum aminopeptidases as a double-faced tool to increase or decrease efficiency of antigen presentation in health and disease. Hum Immunol 2019; 80:277-280. [PMID: 30928619 DOI: 10.1016/j.humimm.2019.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Piotr Kuśnierczyk
- Laboratory of Immunogenetics and Tissue Immunology, The Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
| | - Efstratios Stratikos
- National Centre for Scientific Research Demokritos, Agia Paraskevi, Athens, Greece
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15
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López de Castro JA. How ERAP1 and ERAP2 Shape the Peptidomes of Disease-Associated MHC-I Proteins. Front Immunol 2018; 9:2463. [PMID: 30425713 PMCID: PMC6219399 DOI: 10.3389/fimmu.2018.02463] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/04/2018] [Indexed: 12/28/2022] Open
Abstract
Four inflammatory diseases are strongly associated with Major Histocompatibility Complex class I (MHC-I) molecules: birdshot chorioretinopathy (HLA-A*29:02), ankylosing spondylitis (HLA-B*27), Behçet's disease (HLA-B*51), and psoriasis (HLA-C*06:02). The endoplasmic reticulum aminopeptidases (ERAP) 1 and 2 are also risk factors for these diseases. Since both enzymes are involved in the final processing steps of MHC-I ligands it is reasonable to assume that MHC-I-bound peptides play a significant pathogenetic role. This review will mainly focus on recent studies concerning the effects of ERAP1 and ERAP2 polymorphism and expression on shaping the peptidome of disease-associated MHC-I molecules in live cells. These studies will be discussed in the context of the distinct mechanisms and substrate preferences of both enzymes, their different patterns of genetic association with various diseases, the role of polymorphisms determining changes in enzymatic activity or expression levels, and the distinct peptidomes of disease-associated MHC-I allotypes. ERAP1 and ERAP2 polymorphism and expression induce significant changes in multiple MHC-I-bound peptidomes. These changes are MHC allotype-specific and, without excluding a degree of functional inter-dependence between both enzymes, reflect largely separate roles in their processing of MHC-I ligands. The studies reviewed here provide a molecular basis for the distinct patterns of genetic association of ERAP1 and ERAP2 with disease and for the pathogenetic role of peptides. The allotype-dependent alterations induced on distinct peptidomes may explain that the joint association of both enzymes and unrelated MHC-I alleles influence different pathological outcomes.
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