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Margulies DH, Jiang J, Ahmad J, Boyd LF, Natarajan K. Chaperone function in antigen presentation by MHC class I molecules-tapasin in the PLC and TAPBPR beyond. Front Immunol 2023; 14:1179846. [PMID: 37398669 PMCID: PMC10308438 DOI: 10.3389/fimmu.2023.1179846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Peptide loading of MHC-I molecules plays a critical role in the T cell response to infections and tumors as well as to interactions with inhibitory receptors on natural killer (NK) cells. To facilitate and optimize peptide acquisition, vertebrates have evolved specialized chaperones to stabilize MHC-I molecules during their biosynthesis and to catalyze peptide exchange favoring high affinity or optimal peptides to permit transport to the cell surface where stable peptide/MHC-I (pMHC-I) complexes are displayed and are available for interaction with T cell receptors and any of a host of inhibitory and activating receptors. Although components of the endoplasmic reticulum (ER) resident peptide loading complex (PLC) were identified some 30 years ago, the detailed biophysical parameters that govern peptide selection, binding, and surface display have recently been understood better with advances in structural methods including X-ray crystallography, cryogenic electron microscopy (cryo-EM), and computational modeling. These approaches have provided refined mechanistic illustration of the molecular events involved in the folding of the MHC-I heavy chain, its coordinate glycosylation, assembly with its light chain, β2-microglobulin (β2m), its association with the PLC, and its binding of peptides. Our current view of this important cellular process as it relates to antigen presentation to CD8+ T cells is based on many different approaches: biochemical, genetic, structural, computational, cell biological, and immunological. In this review, taking advantage of recent X-ray and cryo-EM structural evidence and molecular dynamics simulations, examined in the context of past experiments, we attempt a dispassionate evaluation of the details of peptide loading in the MHC-I pathway. By critical evaluation of several decades of investigation, we outline aspects of the peptide loading process that are well-understood and indicate those that demand further detailed investigation. Further studies should contribute not only to basic understanding, but also to applications for immunization and therapy of tumors and infections.
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Lan BH, Becker M, Freund C. The mode of action of tapasin on major histocompatibility class I (MHC-I) molecules. J Biol Chem 2023; 299:102987. [PMID: 36758805 PMCID: PMC10040737 DOI: 10.1016/j.jbc.2023.102987] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 01/05/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023] Open
Abstract
Tapasin (Tsn) plays a critical role in antigen processing and presentation by major histocompatibility complex class I (MHC-I) molecules. The mechanism of Tsn-mediated peptide loading and exchange hinges on the conformational dynamics governing the interaction of Tsn and MHC-I with recent structural and functional studies pinpointing the critical sites of direct or allosteric regulation. In this review, we highlight these recent findings and relate them to the extensive molecular and cellular data that are available for these evolutionary interdependent proteins. Furthermore, allotypic differences of MHC-I with regard to the editing and chaperoning function of Tsn are reviewed and related to the mechanistic observations. Finally, evolutionary aspects of the mode of action of Tsn will be discussed, a short comparison with the Tsn-related molecule TAPBPR (Tsn-related protein) will be given, and the impact of Tsn on noncanonical MHC-I molecules will be described.
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Affiliation(s)
- By Huan Lan
- Institute of Chemistry & Biochemistry, Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Moritz Becker
- Institute of Chemistry & Biochemistry, Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Christian Freund
- Institute of Chemistry & Biochemistry, Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany.
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3
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Structural mechanism of tapasin-mediated MHC-I peptide loading in antigen presentation. Nat Commun 2022; 13:5470. [PMID: 36115831 PMCID: PMC9482634 DOI: 10.1038/s41467-022-33153-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/26/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractLoading of MHC-I molecules with peptide by the catalytic chaperone tapasin in the peptide loading complex plays a critical role in antigen presentation and immune recognition. Mechanistic insight has been hampered by the lack of detailed structural information concerning tapasin–MHC-I. We present here crystal structures of human tapasin complexed with the MHC-I molecule HLA-B*44:05, and with each of two anti-tapasin antibodies. The tapasin-stabilized peptide-receptive state of HLA-B*44:05 is characterized by distortion of the peptide binding groove and destabilization of the β2-microglobulin interaction, leading to release of peptide. Movements of the membrane proximal Ig-like domains of tapasin, HLA-B*44:05, and β2-microglobulin accompany the transition to a peptide-receptive state. Together this ensemble of crystal structures provides insights into a distinct mechanism of tapasin-mediated peptide exchange.
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Müller IK, Winter C, Thomas C, Spaapen RM, Trowitzsch S, Tampé R. Structure of an MHC I–tapasin–ERp57 editing complex defines chaperone promiscuity. Nat Commun 2022; 13:5383. [PMID: 36104323 PMCID: PMC9474470 DOI: 10.1038/s41467-022-32841-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 08/19/2022] [Indexed: 11/24/2022] Open
Abstract
Adaptive immunity depends on cell surface presentation of antigenic peptides by major histocompatibility complex class I (MHC I) molecules and on stringent ER quality control in the secretory pathway. The chaperone tapasin in conjunction with the oxidoreductase ERp57 is crucial for MHC I assembly and for shaping the epitope repertoire for high immunogenicity. However, how the tapasin–ERp57 complex engages MHC I clients has not yet been determined at atomic detail. Here, we present the 2.7-Å crystal structure of a tapasin–ERp57 heterodimer in complex with peptide-receptive MHC I. Our study unveils molecular details of client recognition by the multichaperone complex and highlights elements indispensable for peptide proofreading. The structure of this transient ER quality control complex provides the mechanistic basis for the selector function of tapasin and showcases how the numerous MHC I allomorphs are chaperoned during peptide loading and editing. Adaptive immunity depends on cellular chaperone and quality control systems that are decisive for an effective presentation of foreign antigens via MHC I molecules. Here, the authors present the structure of a key chaperone-MHC I complex.
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Lenart I, Truong LH, Nguyen DD, Rasiukienė O, Tsao E, Armstrong J, Kumar P, McHugh K, Pereira BI, Maan BS, Garstka MA, Bowness P, Blake N, Powis SJ, Gould K, Nesbeth D, Antoniou AN. Intrinsic Folding Properties of the HLA-B27 Heavy Chain Revealed by Single Chain Trimer Versions of Peptide-Loaded Class I Major Histocompatibility Complex Molecules. Front Immunol 2022; 13:902135. [PMID: 35958592 PMCID: PMC9359109 DOI: 10.3389/fimmu.2022.902135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Peptide-loaded Major Histocompatibility Complex (pMHC) class I molecules can be expressed in a single chain trimeric (SCT) format, composed of a specific peptide fused to the light chain beta-2 microglobulin (β2m) and MHC class I heavy chain (HC) by flexible linker peptides. pMHC SCTs have been used as effective molecular tools to investigate cellular immunity and represent a promising vaccine platform technology, due to their intracellular folding and assembly which is apparently independent of host cell folding pathways and chaperones. However, certain MHC class I HC molecules, such as the Human Leukocyte Antigen B27 (HLA-B27) allele, present a challenge due to their tendency to form HC aggregates. We constructed a series of single chain trimeric molecules to determine the behaviour of the HLA-B27 HC in a scenario that usually allows for efficient MHC class I molecule folding. When stably expressed, a pMHC SCT incorporating HLA-B27 HC formed chaperone-bound homodimers within the endoplasmic reticulum (ER). A series of HLA-B27 SCT substitution mutations revealed that the F pocket and antigen binding groove regions of the HLA-B27 HC defined the folding and dimerisation of the single chain complex, independently of the peptide sequence. Furthermore, pMHC SCTs can demonstrate variability in their association with the intracellular antigen processing machinery.
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Affiliation(s)
- Izabela Lenart
- Division of Infection and Immunity/Centre of Rheumatology, University College London, London, United Kingdom
- Centre of Rheumatology, University College London, London, United Kingdom
- Clinical Trials and Regulatory Affairs, Science Pharma, Warsaw, Poland
| | - Linh-Huyen Truong
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- University of Oxford, Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Oxford, United Kingdom
| | - Dinh Dung Nguyen
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- Medical Genetics Department, Medical Genetics centre, Vinmec Research Institute of Stem Cell and Gene Technology, Hanoi, Vietnam
| | - Olga Rasiukienė
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Edward Tsao
- Division of Infection and Immunity/Centre of Rheumatology, University College London, London, United Kingdom
| | - Jonathan Armstrong
- School of Medicine and Biological Sciences Research Complex, University of St. Andrews, Scotland, United Kingdom
| | - Pankaj Kumar
- School of Medicine and Biological Sciences Research Complex, University of St. Andrews, Scotland, United Kingdom
| | - Kirsty McHugh
- The Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, Oxford University, Oxford, United Kingdom
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Branca I. Pereira
- Division of Infection and Immunity/Centre of Rheumatology, University College London, London, United Kingdom
- Centre of Rheumatology, University College London, London, United Kingdom
- Research and Development Department, Chelsea and Westminster Hospital National Health Service (NHS) Foundation Trust, London, United Kingdom
| | - Balraj S. Maan
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- School of Medical Education, The Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Malgorzata A. Garstka
- Core Research Laboratory, Department of Endocrinology, National & Local Joint Engineering Research Center of Biodiagnosis and Biotherapy, Second Affiliated Hospital, School of Medicine, Xi’an Jiaotong University, Xi’an, China
| | - Paul Bowness
- The Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, Oxford University, Oxford, United Kingdom
| | - Neil Blake
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Simon J. Powis
- School of Medicine and Biological Sciences Research Complex, University of St. Andrews, Scotland, United Kingdom
| | - Keith Gould
- Wright-Fleming Institute, Imperial College London, London, United Kingdom
| | - Darren Nesbeth
- The Advanced Centre for Biochemical Engineering, University College London, London, United Kingdom
| | - Antony N. Antoniou
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- The Advanced Centre for Biochemical Engineering, University College London, London, United Kingdom
- *Correspondence: Antony N. Antoniou,
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Arshad N, Laurent-Rolle M, Ahmed WS, Hsu JCC, Mitchell SM, Pawlak J, Sengupta D, Biswas KH, Cresswell P. SARS-CoV-2 accessory proteins ORF7a and ORF3a use distinct mechanisms to downregulate MHC-I surface expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.05.17.492198. [PMID: 35611331 PMCID: PMC9128780 DOI: 10.1101/2022.05.17.492198] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Major histocompatibility complex class I (MHC-I) molecules, which are dimers of a glycosylated polymorphic transmembrane heavy chain and the small protein β 2 -microglobulin (β 2 m), bind peptides in the endoplasmic reticulum that are generated by the cytosolic turnover of cellular proteins. In virus-infected cells these peptides may include those derived from viral proteins. Peptide-MHC-I complexes then traffic through the secretory pathway and are displayed at the cell surface where those containing viral peptides can be detected by CD8 + T lymphocytes that kill infected cells. Many viruses enhance their in vivo survival by encoding genes that downregulate MHC-I expression to avoid CD8 + T cell recognition. Here we report that two accessory proteins encoded by SARS-CoV-2, the causative agent of the ongoing COVID-19 pandemic, downregulate MHC-I expression using distinct mechanisms. One, ORF3a, a viroporin, reduces global trafficking of proteins, including MHC-I, through the secretory pathway. The second, ORF7a, interacts specifically with the MHC-I heavy chain, acting as a molecular mimic of β 2 m to inhibit its association. This slows the exit of properly assembled MHC-I molecules from the endoplasmic reticulum. We demonstrate that ORF7a reduces antigen presentation by the human MHC-I allele HLA-A*02:01. Thus, both ORF3a and ORF7a act post-translationally in the secretory pathway to lower surface MHC-I expression, with ORF7a exhibiting a novel and specific mechanism that allows immune evasion by SARS-CoV-2. Significance Statement Viruses may down-regulate MHC class I expression on infected cells to avoid elimination by cytotoxic T cells. We report that the accessory proteins ORF7a and ORF3a of SARS-CoV-2 mediate this function and delineate the two distinct mechanisms involved. While ORF3a inhibits global protein trafficking to the cell surface, ORF7a acts specifically on MHC-I by competing with β 2 m for binding to the MHC-I heavy chain. This is the first account of molecular mimicry of β 2 m as a viral mechanism of MHC-I down-regulation to facilitate immune evasion.
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Affiliation(s)
- Najla Arshad
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Maudry Laurent-Rolle
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Wesam S Ahmed
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha – 34110, Qatar
| | - Jack Chun-Chieh Hsu
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Susan M Mitchell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Joanna Pawlak
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Debrup Sengupta
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Kabir H Biswas
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha – 34110, Qatar
| | - Peter Cresswell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
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7
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Kawasaki T, Ikegawa M, Kawai T. Antigen Presentation in the Lung. Front Immunol 2022; 13:860915. [PMID: 35615351 PMCID: PMC9124800 DOI: 10.3389/fimmu.2022.860915] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/15/2022] [Indexed: 12/28/2022] Open
Abstract
The lungs are constantly exposed to environmental and infectious agents such as dust, viruses, fungi, and bacteria that invade the lungs upon breathing. The lungs are equipped with an immune defense mechanism that involves a wide variety of immunological cells to eliminate these agents. Various types of dendritic cells (DCs) and macrophages (MACs) function as professional antigen-presenting cells (APCs) that engulf pathogens through endocytosis or phagocytosis and degrade proteins derived from them into peptide fragments. During this process, DCs and MACs present the peptides on their major histocompatibility complex class I (MHC-I) or MHC-II protein complex to naïve CD8+ or CD4+ T cells, respectively. In addition to these cells, recent evidence supports that antigen-specific effector and memory T cells are activated by other lung cells such as endothelial cells, epithelial cells, and monocytes through antigen presentation. In this review, we summarize the molecular mechanisms of antigen presentation by APCs in the lungs and their contribution to immune response.
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Affiliation(s)
| | | | - Taro Kawai
- *Correspondence: Takumi Kawasaki, ; Taro Kawai,
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8
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Bakshi T, Pham D, Kaur R, Sun B. Hidden Relationships between N-Glycosylation and Disulfide Bonds in Individual Proteins. Int J Mol Sci 2022; 23:ijms23073742. [PMID: 35409101 PMCID: PMC8998389 DOI: 10.3390/ijms23073742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 03/25/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
N-Glycosylation (NG) and disulfide bonds (DBs) are two prevalent co/post-translational modifications (PTMs) that are often conserved and coexist in membrane and secreted proteins involved in a large number of diseases. Both in the past and in recent times, the enzymes and chaperones regulating these PTMs have been constantly discovered to directly interact with each other or colocalize in the ER. However, beyond a few model proteins, how such cooperation affects N-glycan modification and disulfide bonding at selective sites in individual proteins is largely unknown. Here, we reviewed the literature to discover the current status in understanding the relationships between NG and DBs in individual proteins. Our results showed that more than 2700 human proteins carry both PTMs, and fewer than 2% of them have been investigated in the associations between NG and DBs. We summarized both these proteins with the reported relationships in the two PTMs and the tools used to discover the relationships. We hope that, by exposing this largely understudied field, more investigations can be encouraged to unveil the hidden relationships of NG and DBs in the majority of membranes and secreted proteins for pathophysiological understanding and biotherapeutic development.
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Affiliation(s)
- Tania Bakshi
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - David Pham
- Department of Computing Science, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Raminderjeet Kaur
- Faculty of Health Science, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Bingyun Sun
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Correspondence:
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9
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Mahmood F, Xu R, Awan MUN, Song Y, Han Q, Xia X, Zhang J. PDIA3: Structure, functions and its potential role in viral infections. Biomed Pharmacother 2021; 143:112110. [PMID: 34474345 DOI: 10.1016/j.biopha.2021.112110] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 02/08/2023] Open
Abstract
The catalysis of disulphide (SS) bonds is the most important characteristic of protein disulphide isomerase (PDI) family. Catalysis occurs in the endoplasmic reticulum, which contains many proteins, most of which are secretory in nature and that have at least one s-s bond. Protein disulphide isomerase A3 (PDIA3) is a member of the PDI family that acts as a chaperone. PDIA3 is highly expressed in response to cellular stress, and also intercept the apoptotic cellular death related to endoplasmic reticulum (ER) stress, and protein misfolding. PDIA3 expression is elevated in almost 70% of cancers and its expression has been linked with overall low cell invasiveness, survival and metastasis. Viral diseases present a significant public health threat. The presence of PDIA3 on the cell surface helps different viruses to enter the cells and also helps in replication. Therefore, inhibitors of PDIA3 have great potential to interfere with viral infections. In this review, we summarize what is known about the basic structure, functions and role of PDIA3 in viral infections. The review will inspire studies of pathogenic mechanisms and drug targeting to counter viral diseases.
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Affiliation(s)
- Faisal Mahmood
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Ruixian Xu
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Maher Un Nisa Awan
- Laboratory of Molecular Neurobiology, Medical Faculty, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Yuzhu Song
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Qinqin Han
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China
| | - Xueshan Xia
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China.
| | - Jinyang Zhang
- Molecular Medicine Research Centre of Yunnan Province, Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 Jingming South Road, Kunming 650500, China.
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Mathematical modeling and stochastic simulations suggest that low-affinity peptides can bisect MHC1-mediated export of high-affinity peptides into "early"- and "late"-phases. Heliyon 2021; 7:e07466. [PMID: 34286133 PMCID: PMC8278427 DOI: 10.1016/j.heliyon.2021.e07466] [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: 03/08/2021] [Revised: 05/23/2021] [Accepted: 06/29/2021] [Indexed: 02/01/2023] Open
Abstract
The peptide loading complex (PLC) is a multi-protein complex of the endoplasmic reticulum (ER) which optimizes major histocompatibility I (MHC1)-mediated export of intracellular high-affinity peptides. Whilst, the molecular biology of MHC1-mediated export is well supported by empirical data, the stoichiometry, kinetics and spatio-temporal profile of the participating molecular entities are a matter of considerable debate. Here, a low-affinity peptide-driven (LAPD)-model of MHC1-mediated high-affinity peptide export is formulated, implemented, analyzed and simulated. The model is parameterized in terms of the contribution of the shunt reaction to the concentration of exportable MHC1. Theoretical analyses and simulation studies of the model suggest that low-affinity peptides can bisect MHC1-mediated export of high-affinity peptides into time-dependent distinct “early”- and “late”-phases. The net exportable MHC1 (eM1β(t)) is a function of the retrograde (rM1β(t))- and anterograde (aM1β(t))-derived fractions. The “early”-phase is dominated by the contribution of the retrograde/recyclable (rM1β≈61%,aM1β≈39%) pathway to exportable MHC1, is characterized by Tapasin-mediated peptide-editing and is ATP-independent. The “late”-phase on the other hand, is characterized by de novo PLC-assembly, rapid disassembly and a significant contribution of the anterograde pathway to exportable MHC1 (rM1β≈21%,aM1β≈79%). The shunt reaction is rate limiting and may integrate peptide translocation with PLC-assembly/disassembly thereby, regulating peptide export under physiological and pathological (viral infections, dysplastic alterations) conditions.
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11
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Light control of the peptide-loading complex synchronizes antigen translocation and MHC I trafficking. Commun Biol 2021; 4:430. [PMID: 33785857 PMCID: PMC8010092 DOI: 10.1038/s42003-021-01890-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 02/17/2021] [Indexed: 12/16/2022] Open
Abstract
Antigen presentation via major histocompatibility complex class I (MHC I) molecules is essential to mount an adaptive immune response against pathogens and cancerous cells. To this end, the transporter associated with antigen processing (TAP) delivers snippets of the cellular proteome, resulting from proteasomal degradation, into the ER lumen. After peptide loading and editing by the peptide-loading complex (PLC), stable peptide-MHC I complexes are released for cell surface presentation. Since the process of MHC I trafficking is poorly defined, we established an approach to control antigen presentation by introduction of a photo-caged amino acid in the catalytic ATP-binding site of TAP. By optical control, we initiate TAP-dependent antigen translocation, thus providing new insights into TAP function within the PLC and MHC I trafficking in living cells. Moreover, this versatile approach has the potential to be applied in the study of other cellular pathways controlled by P-loop ATP/GTPases. Brunnberg et al. establish a protocol that enables them to optically control translocation of the transporter associated with antigen processing (TAP), which plays a role in delivering proteasomal degradation products into the ER lumen. Their versatile approach provides insights into TAP function in the context of peptide-loading complex and stable peptide-MHC I complex trafficking in living cells, but has the potential to be applied to the investigation of other pathways.
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12
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Sabbatino F, Liguori L, Polcaro G, Salvato I, Caramori G, Salzano FA, Casolaro V, Stellato C, Dal Col J, Pepe S. Role of Human Leukocyte Antigen System as A Predictive Biomarker for Checkpoint-Based Immunotherapy in Cancer Patients. Int J Mol Sci 2020; 21:ijms21197295. [PMID: 33023239 PMCID: PMC7582904 DOI: 10.3390/ijms21197295] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/26/2020] [Accepted: 09/29/2020] [Indexed: 12/11/2022] Open
Abstract
Recent advances in cancer immunotherapy have clearly shown that checkpoint-based immunotherapy is effective in a small subgroup of cancer patients. However, no effective predictive biomarker has been identified so far. The major histocompatibility complex, better known in humans as human leukocyte antigen (HLA), is a very polymorphic gene complex consisting of more than 200 genes. It has a crucial role in activating an appropriate host immune response against pathogens and tumor cells by discriminating self and non-self peptides. Several lines of evidence have shown that down-regulation of expression of HLA class I antigen derived peptide complexes by cancer cells is a mechanism of tumor immune escape and is often associated to poor prognosis in cancer patients. In addition, it has also been shown that HLA class I and II antigen expression, as well as defects in the antigen processing machinery complex, may predict tumor responses in cancer immunotherapy. Nevertheless, the role of HLA in predicting tumor responses to checkpoint-based immunotherapy is still debated. In this review, firstly, we will describe the structure and function of the HLA system. Secondly, we will summarize the HLA defects and their clinical significance in cancer patients. Thirdly, we will review the potential role of the HLA as a predictive biomarker for checkpoint-based immunotherapy in cancer patients. Lastly, we will discuss the potential strategies that may restore HLA function to implement novel therapeutic strategies in cancer patients.
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Affiliation(s)
- Francesco Sabbatino
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
- Oncology Unit, AOU San Giovanni di Dio e Ruggi D’Aragona, 84131 Salerno, Italy
| | - Luigi Liguori
- Department of Clinical Medicine and Surgery, University of Naples “Federico II”, 80131 Naples, Italy;
| | - Giovanna Polcaro
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
| | - Ilaria Salvato
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
- Pulmonary Unit, Department of Biomedical Sciences, Dentistry, Morphological and Functional Imaging (BIOMORF), University of Messina, 98125 Messina, Italy;
| | - Gaetano Caramori
- Pulmonary Unit, Department of Biomedical Sciences, Dentistry, Morphological and Functional Imaging (BIOMORF), University of Messina, 98125 Messina, Italy;
| | - Francesco A. Salzano
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
| | - Vincenzo Casolaro
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
| | - Cristiana Stellato
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
| | - Jessica Dal Col
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
- Correspondence: ; Tel.: +39-08996-5210
| | - Stefano Pepe
- Department of Medicine, Surgery and Dentistry ’Scuola Medica Salernitana’, University of Salerno, 84081 Baronissi, Salerno, Italy; (F.S.); (G.P.); (I.S.); (F.A.S.); (V.C.); (C.S.); (S.P.)
- Oncology Unit, AOU San Giovanni di Dio e Ruggi D’Aragona, 84131 Salerno, Italy
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13
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Ilca FT, Drexhage LZ, Brewin G, Peacock S, Boyle LH. Distinct Polymorphisms in HLA Class I Molecules Govern Their Susceptibility to Peptide Editing by TAPBPR. Cell Rep 2020; 29:1621-1632.e3. [PMID: 31693900 PMCID: PMC7057265 DOI: 10.1016/j.celrep.2019.09.074] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/28/2019] [Accepted: 09/25/2019] [Indexed: 12/20/2022] Open
Abstract
Understanding how peptide selection is controlled on different major histocompatibility complex class I (MHC I) molecules is pivotal for determining how variations in these proteins influence our predisposition to infectious diseases, cancer, and autoinflammatory conditions. Although the intracellular chaperone TAPBPR edits MHC I peptides, it is unclear which allotypes are subjected to TAPBPR-mediated peptide editing. Here, we examine the ability of 97 different human leukocyte antigen (HLA) class I allotypes to interact with TAPBPR. We reveal a striking preference of TAPBPR for HLA-A, particularly for supertypes A2 and A24, over HLA-B and -C molecules. We demonstrate that the increased propensity of these HLA-A molecules to undergo TAPBPR-mediated peptide editing is determined by molecular features of the HLA-A F pocket, specifically residues H114 and Y116. This work reveals that specific polymorphisms in MHC I strongly influence their susceptibility to chaperone-mediated peptide editing, which may play a significant role in disease predisposition.
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Affiliation(s)
- F Tudor Ilca
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Linnea Z Drexhage
- Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, 79104 Freiburg, Germany
| | - Gemma Brewin
- Tissue Typing Laboratory, Box 209, Level 6 ATC, Cambridge University Hospitals, NHS Foundation Trust, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0QQ, UK
| | - Sarah Peacock
- Tissue Typing Laboratory, Box 209, Level 6 ATC, Cambridge University Hospitals, NHS Foundation Trust, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0QQ, UK
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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14
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Ilca T, Boyle LH. The Ins and Outs of TAPBPR. Curr Opin Immunol 2020; 64:146-151. [PMID: 32814254 DOI: 10.1016/j.coi.2020.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 06/25/2020] [Indexed: 11/26/2022]
Abstract
Peptide presentation on MHC class I molecules (MHC-I) is central to mounting effective antiviral and antitumoral immune responses. The tapasin-related protein TAPBPR is an MHC-I peptide editor which shapes the final peptide repertoire displayed on the cell surface. Here, we review recent findings which further elucidate the mechanisms by which TAPBPR performs peptide editing on a molecular level, and how glycosylation on MHC-I influences the interaction with TAPBPR and the peptide loading complex. We also explore how the function of TAPBPR can be utilized to promote exogenous peptide loading directly onto plasma-membrane expressed MHC-I. This has led to the development of new assays to investigate TAPBPR-mediated peptide editing and uncovered translational opportunities of utilizing TAPBPR to treat human disease.
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Affiliation(s)
- Tudor Ilca
- Department of Pathology, University of Cambridge, UK
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15
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Padariya M, Kalathiya U, Houston DR, Alfaro JA. Recognition Dynamics of Cancer Mutations on the ERp57-Tapasin Interface. Cancers (Basel) 2020; 12:cancers12030737. [PMID: 32244998 PMCID: PMC7140079 DOI: 10.3390/cancers12030737] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/05/2020] [Accepted: 03/18/2020] [Indexed: 01/16/2023] Open
Abstract
Down regulation of the major histocompatibility class (MHC) I pathway plays an important role in tumour development, and can be achieved by suppression of HLA expression or mutations in the MHC peptide-binding pocket. The peptide-loading complex (PLC) loads peptides on the MHC-I molecule in a dynamic multi-step assembly process. The effects of cancer variants on ERp57 and tapasin components from the MHC-I pathway is less known, and they could have an impact on antigen presentation. Applying computational approaches, we analysed whether the ERp57-tapasin binding might be altered by missense mutations. The variants H408R(ERp57) and P96L, D100A, G183R(tapasin) at the protein–protein interface improved protein stability (ΔΔG) during the initial screen of 14 different variants. The H408R(ERp57) and P96L(tapasin) variants, located close to disulphide bonds, were further studied by molecular dynamics (MD). Identifying intramolecular a-a’ domain interactions, MD revealed open and closed conformations of ERp57 in the presence and absence of tapasin. In wild-type and mutant ERp57-tapasin complexes, residues Val97, Ser98, Tyr100, Trp405, Gly407(ERp57) and Asn94, Cys95, Arg97, Asp100(tapasin) formed common H-bond interactions. Moreover, comparing the H-bond networks for P96L and H408R with each other, suggests that P96L(tapasin) improved ERp57-tapasin binding more than the H408R(ERp57) mutant. During MD, the C-terminus domain (that binds MHC-I) in tapasin from the ERp57(H408R)-tapasin complex moved away from the PLC, whereas in the ERp57-tapasin(P96L) system was oppositely displaced. These findings can have implications for the function of PLC and, ultimately, for the presentation of MHC-I peptide complex on the tumour cell surface.
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Affiliation(s)
- Monikaben Padariya
- International Centre for Cancer Vaccine Science, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland;
- Correspondence: (M.P.); (J.A.A.)
| | - Umesh Kalathiya
- International Centre for Cancer Vaccine Science, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland;
| | - Douglas R. Houston
- Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh, Scotland EH9 3BF, UK;
| | - Javier Antonio Alfaro
- International Centre for Cancer Vaccine Science, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland;
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland EH4 2XR, UK
- Correspondence: (M.P.); (J.A.A.)
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16
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A personal retrospective on the mechanisms of antigen processing. Immunogenetics 2019; 71:141-160. [PMID: 30694344 DOI: 10.1007/s00251-018-01098-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 11/22/2018] [Indexed: 10/27/2022]
Abstract
My intention here is to describe the history of the molecular aspects of the antigen processing field from a personal perspective, beginning with the early identification of the species that we now know as MHC class I and MHC class II molecules, to the recognition that their stable surface expression and detection by T cells depends on peptide association, and to the unraveling of the biochemical and cell biological mechanisms that regulate peptide binding. One goal is to highlight the role that serendipity or, more colloquially, pure blind luck can play in advancing the research enterprise when it is combined with an appropriately receptive mind. This is not intended to be an overarching review, and because of my own work I focus primarily on studies of the human MHC. This means that I neglect the work of many other individuals who made advances in other species, particularly those who produced the many knockout mouse strains used to demonstrate the importance of the antigen processing machinery for initiating immune responses. I apologize in advance to colleagues around the globe whose contributions I deal with inadequately for these reasons, and to those whose foundational work is now firmly established in text books and therefore not cited. So many individuals have worked to advance the field that giving all of them the credit they deserve is almost impossible. I have attempted, while focusing on work from my own laboratory, to point out contemporaneous or sometimes earlier advances made by others. Much of the success of my own laboratory came because we simultaneously worked on both the MHC class I and class II systems and used the findings in one area to inform the other, but mainly it depended on the extraordinary group of students and fellows who have worked on these projects over the years. To those who worked in other areas who are not mentioned here, rest assured that I appreciate your efforts just as much.
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17
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Ilca FT, Neerincx A, Wills MR, de la Roche M, Boyle LH. Utilizing TAPBPR to promote exogenous peptide loading onto cell surface MHC I molecules. Proc Natl Acad Sci U S A 2018; 115:E9353-E9361. [PMID: 30213851 PMCID: PMC6176578 DOI: 10.1073/pnas.1809465115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The repertoire of peptides displayed at the cell surface by MHC I molecules is shaped by two intracellular peptide editors, tapasin and TAPBPR. While cell-free assays have proven extremely useful in identifying the function of both of these proteins, here we explored whether a more physiological system could be developed to assess TAPBPR-mediated peptide editing on MHC I. We reveal that membrane-associated TAPBPR targeted to the plasma membrane retains its ability to function as a peptide editor and efficiently catalyzes peptide exchange on surface-expressed MHC I molecules. Additionally, we show that soluble TAPBPR, consisting of the luminal domain alone, added to intact cells, also functions as an effective peptide editor on surface MHC I molecules. Thus, we have established two systems in which TAPBPR-mediated peptide exchange on MHC class I can be interrogated. Furthermore, we could use both plasma membrane-targeted and exogenous soluble TAPBPR to display immunogenic peptides on surface MHC I molecules and consequently induce T cell receptor engagement, IFN-γ secretion, and T cell-mediated killing of target cells. Thus, we have developed an efficient way to by-pass the natural antigen presentation pathway of cells and load immunogenic peptides of choice onto cells. Our findings highlight a potential therapeutic use for TAPBPR in increasing the immunogenicity of tumors in the future.
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Affiliation(s)
- F Tudor Ilca
- Department of Pathology, University of Cambridge, CB2 1QP Cambridge, United Kingdom
| | - Andreas Neerincx
- Department of Pathology, University of Cambridge, CB2 1QP Cambridge, United Kingdom
| | - Mark R Wills
- Department of Medicine, University of Cambridge, Addenbrookes Hospital, CB2 0QQ Cambridge, United Kingdom
| | - Maike de la Roche
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, CB2 0RE Cambridge, United Kingdom
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, CB2 1QP Cambridge, United Kingdom;
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18
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Trowitzsch S, Tampé R. ABC Transporters in Dynamic Macromolecular Assemblies. J Mol Biol 2018; 430:4481-4495. [DOI: 10.1016/j.jmb.2018.07.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 07/24/2018] [Accepted: 07/30/2018] [Indexed: 12/28/2022]
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19
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Neerincx A, Boyle LH. Preferential interaction of MHC class I with TAPBPR in the absence of glycosylation. Mol Immunol 2018; 113:58-66. [PMID: 30077416 PMCID: PMC6859791 DOI: 10.1016/j.molimm.2018.06.269] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 04/23/2018] [Accepted: 06/14/2018] [Indexed: 11/17/2022]
Abstract
We recently discovered that TAPBPR promotes reglucosylation of the N-linked glycan on MHC class I molecules, a modification that restores their recognition by calreticulin and reincorporation into the peptide-loading complex. We wondered whether TAPBPR displayed some degree of glycan specificity, as is known to be the case for tapasin via its interaction with calreticulin & ERp57, or whether its interaction with MHC class I was glycan independent. Here, we explored this by comparing the ability of TAPBPR to bind to MHC class I containing either an intact or disrupted NxS/T glycosylation consensus sequence. In contrast to tapasin, TAPBPR bound strongly to MHC class I molecules that lacked N-linked glycosylation, suggesting that the TAPBPR:MHC class I interaction is glycan independent. Furthermore, we found that glycosylated HLA-A2 preferentially interacts with tapasin rather than TAPBPR, possibly explaining, in part, why MHC class I molecules bind efficiently to tapasin in the face of an alternative chaperone. The distinction in glycan specificity between the two peptide editors suggests that TAPBPR may bind to MHC class I molecules that are associated with a broader diversity of oligosaccharides attached compared with tapasin. This may explain, to some extent, the ability of TAPBPR to interact with MHC class I molecules outside of the ER.
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Affiliation(s)
- Andreas Neerincx
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
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20
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Arshad N, Cresswell P. Tumor-associated calreticulin variants functionally compromise the peptide loading complex and impair its recruitment of MHC-I. J Biol Chem 2018; 293:9555-9569. [PMID: 29769311 DOI: 10.1074/jbc.ra118.002836] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/10/2018] [Indexed: 12/22/2022] Open
Abstract
Major histocompatibility complex-I-β2m dimers (MHC-I) bind peptides derived from intracellular proteins, enabling the immune system to distinguish between normal cells and those expressing pathogen-derived or mutant proteins. The peptides bind to MHC-I in the endoplasmic reticulum (ER), and this binding is facilitated by the peptide loading complex (PLC), which contains calreticulin (CRT). CRT associates with MHC-I via a conserved glycan present on MHC-I and recruits it to the PLC for peptide binding. Somatic frameshift mutations in CRT (CRT-FS) drive the proliferation of a subset of myeloproliferative neoplasms, which are chronic blood tumors. All CRT-FS proteins have a C-terminal sequence lacking the normal ER-retention signal and possessing a net negative charge rather than the normal positive charge. We characterized the effect of CRT-FS on antigen presentation by MHC-I in human cells. Our results indicate that CRT-FS cannot mediate CRT's peptide loading function in the PLC. Cells lacking CRT exhibited reduced surface MHC-I levels, consistent with reduced binding of high-affinity peptides, and this was not reversed by CRT-FS expression. CRT-FS was secreted and not detectably associated with the PLC, leading to poor MHC-I recruitment, although CRT-FS could still associate with MHC-I in a glycan-dependent manner. The addition of an ER-retention sequence to CRT-FS restored its association with the PLC but did not rescue MHC-I recruitment or its surface expression, indicating that the CRT-FS mutants functionally compromise the PLC. MHC-I down-regulation permits tumor cells to evade immune surveillance, and these findings may therefore be relevant for designing effective immunotherapies for managing myeloproliferative neoplasms.
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Affiliation(s)
| | - Peter Cresswell
- From the Departments of Immunobiology and .,Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8011
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21
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Sever L, Vo NTK, Bols NC, Dixon B. Tapasin's protein interactions in the rainbow trout peptide-loading complex. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 81:262-270. [PMID: 29253558 DOI: 10.1016/j.dci.2017.12.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/14/2017] [Accepted: 12/14/2017] [Indexed: 06/07/2023]
Abstract
Major histocompatibility complex (MHC) class I receptors play a key role in the immune system by presenting non-self peptides to T cell lymphocytes. In humans, the assembly of the MHC class I with a peptide is mediated by machinery in the endoplasmic reticulum referred as the peptide loading complex (PLC). Although, the identity of the PLC has been widely explored in humans, this complex has not been characterized in fish. Co-immunoprecipitation and mass spectrometry analysis revealed that the protein-protein interactions which exist in the human PLC are conserved in the monocyte/macrophage rainbow trout cell line (RTS11), in particular the interaction of tapasin with the transporter associated with antigen processing (TAP), MHC class I and ERp57. Importantly, a 20 kDa tapasin version that contains an intact C and N terminal domains was found to associate with ERp57 and form a 75 kDa heterodimer. These results suggest a possible novel alternative spliced version of tapasin may regulate the formation of the peptide-loading complex in teleosts.
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Affiliation(s)
- Lital Sever
- Department of Biology, University of Waterloo, 200 University Ave W. Waterloo, Ontario, N2L 3G1, Canada
| | - Nguyen T K Vo
- Department of Biology, University of Waterloo, 200 University Ave W. Waterloo, Ontario, N2L 3G1, Canada
| | - Niels C Bols
- Department of Biology, University of Waterloo, 200 University Ave W. Waterloo, Ontario, N2L 3G1, Canada
| | - Brian Dixon
- Department of Biology, University of Waterloo, 200 University Ave W. Waterloo, Ontario, N2L 3G1, Canada.
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22
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Whole genome duplications have provided teleosts with many roads to peptide loaded MHC class I molecules. BMC Evol Biol 2018; 18:25. [PMID: 29471808 PMCID: PMC5824609 DOI: 10.1186/s12862-018-1138-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/15/2018] [Indexed: 12/31/2022] Open
Abstract
Background In sharks, chickens, rats, frogs, medaka and zebrafish there is haplotypic variation in MHC class I and closely linked genes involved in antigen processing, peptide translocation and peptide loading. At least in chicken, such MHCIa haplotypes of MHCIa, TAP2 and Tapasin are shown to influence the repertoire of pathogen epitopes being presented to CD8+ T-cells with subsequent effect on cell-mediated immune responses. Results Examining MHCI haplotype variation in Atlantic salmon using transcriptome and genome resources we found little evidence for polymorphism in antigen processing genes closely linked to the classical MHCIa genes. Looking at other genes involved in MHCI assembly and antigen processing we found retention of functional gene duplicates originating from the second vertebrate genome duplication event providing cyprinids, salmonids, and neoteleosts with the potential of several different peptide-loading complexes. One of these gene duplications has also been retained in the tetrapod lineage with orthologs in frogs, birds and opossum. Conclusion We postulate that the unique salmonid whole genome duplication (SGD) is responsible for eliminating haplotypic content in the paralog MHCIa regions possibly due to frequent recombination and reorganization events at early stages after the SGD. In return, multiple rounds of whole genome duplications has provided Atlantic salmon, other teleosts and even lower vertebrates with alternative peptide loading complexes. How this affects antigen presentation remains to be established. Electronic supplementary material The online version of this article (10.1186/s12862-018-1138-9) contains supplementary material, which is available to authorized users.
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23
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van Hateren A, Anderson M, Bailey A, Werner JM, Skipp P, Elliott T. Direct evidence for conformational dynamics in major histocompatibility complex class I molecules. J Biol Chem 2017; 292:20255-20269. [PMID: 29021251 PMCID: PMC5724011 DOI: 10.1074/jbc.m117.809624] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/25/2017] [Indexed: 12/19/2022] Open
Abstract
Major histocompatibility complex class I molecules (MHC I) help protect jawed vertebrates by binding and presenting immunogenic peptides to cytotoxic T lymphocytes. Peptides are selected from a large diversity present in the endoplasmic reticulum. However, only a limited number of peptides complement the polymorphic MHC specificity determining pockets in a way that leads to high-affinity peptide binding and efficient antigen presentation. MHC I molecules possess an intrinsic ability to discriminate between peptides, which varies in efficiency between allotypes, but the mechanism of selection is unknown. Elucidation of the selection mechanism is likely to benefit future immune-modulatory therapies. Evidence suggests peptide selection involves transient adoption of alternative, presumably higher energy conformations than native peptide-MHC complexes. However, the instability of peptide-receptive MHC molecules has hindered characterization of such conformational plasticity. To investigate the dynamic nature of MHC, we refolded MHC proteins with peptides that can be hydrolyzed by UV light and thus released. We compared the resultant peptide-receptive MHC molecules with non-hydrolyzed peptide-loaded MHC complexes by monitoring the exchange of hydrogen for deuterium in solution. We found differences in hydrogen-deuterium exchange between peptide-loaded and peptide-receptive molecules that were negated by the addition of peptide to peptide-receptive MHC molecules. Peptide hydrolysis caused significant increases in hydrogen-deuterium exchange in sub-regions of the peptide-binding domain and smaller increases elsewhere, including in the α3 domain and the non-covalently associated β2-microglobulin molecule, demonstrating long-range dynamic communication. Comparing two MHC allotypes revealed allotype-specific differences in hydrogen-deuterium exchange, consistent with the notion that MHC I plasticity underpins peptide selection.
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Affiliation(s)
- Andy van Hateren
- Institute for Life Sciences and Centre for Cancer Immunology, Faculty of Medicine, Southampton SO17 1BJ
| | - Malcolm Anderson
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, United Kingdom
| | - Alistair Bailey
- Institute for Life Sciences and Centre for Cancer Immunology, Faculty of Medicine, Southampton SO17 1BJ; Centre for Proteomic Research, Biological Sciences, and Institute for Life Sciences, Southampton SO17 1BJ
| | - Jörn M Werner
- Institute for Life Sciences, Centre for Biological Sciences, and Faculty of Natural and Environmental Sciences, University of Southampton, Building 85, Southampton SO17 1BJ
| | - Paul Skipp
- Centre for Proteomic Research, Biological Sciences, and Institute for Life Sciences, Southampton SO17 1BJ
| | - Tim Elliott
- Institute for Life Sciences and Centre for Cancer Immunology, Faculty of Medicine, Southampton SO17 1BJ.
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24
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Structure of the human MHC-I peptide-loading complex. Nature 2017; 551:525-528. [PMID: 29107940 DOI: 10.1038/nature24627] [Citation(s) in RCA: 241] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/12/2017] [Indexed: 12/14/2022]
Abstract
The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum that is essential for establishing a hierarchical immune response. The PLC coordinates peptide translocation into the endoplasmic reticulum with loading and editing of major histocompatibility complex class I (MHC-I) molecules. After final proofreading in the PLC, stable peptide-MHC-I complexes are released to the cell surface to evoke a T-cell response against infected or malignant cells. Sampling of different MHC-I allomorphs requires the precise coordination of seven different subunits in a single macromolecular assembly, including the transporter associated with antigen processing (TAP1 and TAP2, jointly referred to as TAP), the oxidoreductase ERp57, the MHC-I heterodimer, and the chaperones tapasin and calreticulin. The molecular organization of and mechanistic events that take place in the PLC are unknown owing to the heterogeneous composition and intrinsically dynamic nature of the complex. Here, we isolate human PLC from Burkitt's lymphoma cells using an engineered viral inhibitor as bait and determine the structure of native PLC by electron cryo-microscopy. Two endoplasmic reticulum-resident editing modules composed of tapasin, calreticulin, ERp57, and MHC-I are centred around TAP in a pseudo-symmetric orientation. A multivalent chaperone network within and across the editing modules establishes the proofreading function at two lateral binding platforms for MHC-I molecules. The lectin-like domain of calreticulin senses the MHC-I glycan, whereas the P domain reaches over the MHC-I peptide-binding pocket towards ERp57. This arrangement allows tapasin to facilitate peptide editing by clamping MHC-I. The translocation pathway of TAP opens out into a large endoplasmic reticulum lumenal cavity, confined by the membrane entry points of tapasin and MHC-I. Two lateral windows channel the antigenic peptides to MHC-I. Structures of PLC captured at distinct assembly states provide mechanistic insight into the recruitment and release of MHC-I. Our work defines the molecular symbiosis of an ABC transporter and an endoplasmic reticulum chaperone network in MHC-I assembly and provides insight into the onset of the adaptive immune response.
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25
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Abstract
The protein disulfide isomerase (PDI) gene family is a protein family classically characterized by endoplasmic reticulum (ER) localization and isomerase and redox activity. ERp57, a prominent multifunctional member of the PDI family, is detected at various levels in multiple cellular localizations outside of the ER. ERp57 has been functionally linked to a host of physiological processes and numerous studies have demonstrated altered expression and aberrant functionality of ERp57 in association with diverse pathological states. Here, we summarize available knowledge of ERp57's functions in subcellular compartments and the roles of dysregulated ERp57 in various diseases toward an emphasis on the potential utility of therapeutic development of ERp57.
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Affiliation(s)
- Aubryanna Hettinghouse
- Department of Orthopaedic Surgery, New York University Medical Center, New York, NY 10003, USA
| | - Ronghan Liu
- Department of Orthopaedic Surgery, New York University Medical Center, New York, NY 10003, USA
| | - Chuan-Ju Liu
- Department of Orthopaedic Surgery, New York University Medical Center, New York, NY 10003, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
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26
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Neerincx A, Boyle LH. Properties of the tapasin homologue TAPBPR. Curr Opin Immunol 2017; 46:97-102. [PMID: 28528220 DOI: 10.1016/j.coi.2017.04.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/01/2017] [Accepted: 04/17/2017] [Indexed: 11/17/2022]
Abstract
The presentation of antigenic peptides by MHC class I molecules plays a vital role in generating T cell responses against infection and cancer. Over the last two decades the central role of tapasin as a peptide editor that influences the loading and optimisation of peptides onto MHC class I molecules has been extensively characterised. Recently, it has become evident that the tapasin-related protein, TAPBPR, functions as a second peptide editor which influences the peptides displayed by MHC class I molecules. Here, we review the discovery of TAPBPR and current understanding of this novel protein in relation to its closest homologue tapasin.
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Affiliation(s)
- Andreas Neerincx
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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Neerincx A, Hermann C, Antrobus R, van Hateren A, Cao H, Trautwein N, Stevanović S, Elliott T, Deane JE, Boyle LH. TAPBPR bridges UDP-glucose:glycoprotein glucosyltransferase 1 onto MHC class I to provide quality control in the antigen presentation pathway. eLife 2017; 6:e23049. [PMID: 28425917 PMCID: PMC5441866 DOI: 10.7554/elife.23049] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 04/14/2017] [Indexed: 11/24/2022] Open
Abstract
Recently, we revealed that TAPBPR is a peptide exchange catalyst that is important for optimal peptide selection by MHC class I molecules. Here, we asked whether any other co-factors associate with TAPBPR, which would explain its effect on peptide selection. We identify an interaction between TAPBPR and UDP-glucose:glycoprotein glucosyltransferase 1 (UGT1), a folding sensor in the calnexin/calreticulin quality control cycle that is known to regenerate the Glc1Man9GlcNAc2 moiety on glycoproteins. Our results suggest the formation of a multimeric complex, dependent on a conserved cysteine at position 94 in TAPBPR, in which TAPBPR promotes the association of UGT1 with peptide-receptive MHC class I molecules. We reveal that the interaction between TAPBPR and UGT1 facilities the reglucosylation of the glycan on MHC class I molecules, promoting their recognition by calreticulin. Our results suggest that in addition to being a peptide editor, TAPBPR improves peptide optimisation by promoting peptide-receptive MHC class I molecules to associate with the peptide-loading complex.
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Affiliation(s)
- Andreas Neerincx
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Clemens Hermann
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Andy van Hateren
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- Institute for Life Science, University of Southampton, Southampton, United Kingdom
| | - Huan Cao
- Division of Applied Medicine, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Nico Trautwein
- Department of Immunology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Stefan Stevanović
- Department of Immunology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Tim Elliott
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- Institute for Life Science, University of Southampton, Southampton, United Kingdom
| | - Janet E Deane
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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van Hateren A, Bailey A, Elliott T. Recent advances in Major Histocompatibility Complex (MHC) class I antigen presentation: Plastic MHC molecules and TAPBPR-mediated quality control. F1000Res 2017; 6:158. [PMID: 28299193 PMCID: PMC5321123 DOI: 10.12688/f1000research.10474.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/13/2017] [Indexed: 01/25/2023] Open
Abstract
We have known since the late 1980s that the function of classical major histocompatibility complex (MHC) class I molecules is to bind peptides and display them at the cell surface to cytotoxic T cells. Recognition by these sentinels of the immune system can lead to the destruction of the presenting cell, thus protecting the host from pathogens and cancer. Classical MHC class I molecules (MHC I hereafter) are co-dominantly expressed, polygenic, and exceptionally polymorphic and have significant sequence diversity. Thus, in most species, there are many different MHC I allotypes expressed, each with different peptide-binding specificity, which can have a dramatic effect on disease outcome. Although MHC allotypes vary in their primary sequence, they share common tertiary and quaternary structures. Here, we review the evidence that, despite this commonality, polymorphic amino acid differences between allotypes alter the ability of MHC I molecules to change shape (that is, their conformational plasticity). We discuss how the peptide loading co-factor tapasin might modify this plasticity to augment peptide loading. Lastly, we consider recent findings concerning the functions of the non-classical MHC I molecule HLA-E as well as the tapasin-related protein TAPBPR (transporter associated with antigen presentation binding protein-related), which has been shown to act as a second quality-control stage in MHC I antigen presentation.
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Affiliation(s)
- Andy van Hateren
- Institute for Life Sciences and Cancer Sciences Unit, University of Southampton, Southampton, UK
| | - Alistair Bailey
- Institute for Life Sciences and Cancer Sciences Unit, University of Southampton, Southampton, UK
| | - Tim Elliott
- Institute for Life Sciences and Cancer Sciences Unit, University of Southampton, Southampton, UK
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29
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Thomas C, Tampé R. Proofreading of Peptide-MHC Complexes through Dynamic Multivalent Interactions. Front Immunol 2017; 8:65. [PMID: 28228754 PMCID: PMC5296336 DOI: 10.3389/fimmu.2017.00065] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/16/2017] [Indexed: 11/18/2022] Open
Abstract
The adaptive immune system is able to detect and destroy cells that are malignantly transformed or infected by intracellular pathogens. Specific immune responses against these cells are elicited by antigenic peptides that are presented on major histocompatibility complex class I (MHC I) molecules and recognized by cytotoxic T lymphocytes at the cell surface. Since these MHC I-presented peptides are generated in the cytosol by proteasomal protein degradation, they can be metaphorically described as a window providing immune cells with insights into the state of the cellular proteome. A crucial element of MHC I antigen presentation is the peptide-loading complex (PLC), a multisubunit machinery, which contains as key constituents the transporter associated with antigen processing (TAP) and the MHC I-specific chaperone tapasin (Tsn). While TAP recognizes and shuttles the cytosolic antigenic peptides into the endoplasmic reticulum (ER), Tsn samples peptides in the ER for their ability to form stable complexes with MHC I, a process called peptide proofreading or peptide editing. Through its selection of peptides that improve MHC I stability, Tsn contributes to the hierarchy of immunodominant peptide epitopes. Despite the fact that it concerns a key event in adaptive immunity, insights into the catalytic mechanism of peptide proofreading carried out by Tsn have only lately been gained via biochemical, biophysical, and structural studies. Furthermore, a Tsn homolog called TAP-binding protein-related (TAPBPR) has only recently been demonstrated to function as a second MHC I-specific chaperone and peptide proofreader. Although TAPBPR is PLC-independent and has a distinct allomorph specificity, it is likely to share a common catalytic mechanism with Tsn. This review focuses on the current knowledge of the multivalent protein–protein interactions and the concomitant dynamic molecular processes underlying peptide-proofreading catalysis. We do not only derive a model that highlights the common mechanistic principles shared by the MHC I editors Tsn and TAPBPR, and the MHC II editor HLA-DM, but also illustrate the distinct quality control strategies employed by these chaperones to sample epitopes. Unraveling the mechanistic underpinnings of catalyzed peptide proofreading will be crucial for a thorough understanding of many aspects of immune recognition, from infection control and tumor immunity to autoimmune diseases and transplant rejection.
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Affiliation(s)
- Christoph Thomas
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt , Frankfurt am Main , Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt , Frankfurt am Main , Germany
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30
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Gaucci E, Raimondo D, Grillo C, Cervoni L, Altieri F, Nittari G, Eufemi M, Chichiarelli S. Analysis of the interaction of calcitriol with the disulfide isomerase ERp57. Sci Rep 2016; 6:37957. [PMID: 27897272 PMCID: PMC5126700 DOI: 10.1038/srep37957] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 10/21/2016] [Indexed: 01/03/2023] Open
Abstract
Calcitriol, the active form of vitamin D3, can regulate the gene expression through the binding to the nuclear receptor VDR, but it can also display nongenomic actions, acting through a membrane-associated receptor, which has been discovered as the disulfide isomerase ERp57. The aim of our research is to identify the binding sites for calcitriol in ERp57 and to analyze their interaction. We first studied the interaction through bioinformatics and fluorimetric analyses. Subsequently, we focused on two protein mutants containing the predicted interaction domains with calcitriol: abb'-ERp57, containing the first three domains, and a'-ERp57, the fourth domain only. To consolidate the achievements we used the calorimetric approach to the whole protein and its mutants. Our results allow us to hypothesize that the interaction with the a' domain contributes to a greater extent than the other potential binding sites to the dissociation constant, calculated as a Kd of about 10-9 M.
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Affiliation(s)
- Elisa Gaucci
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Domenico Raimondo
- Stem Cell Lab - Department of Molecular Medicine - Sapienza Università di Roma, Viale Regina Elena 324, 00161, Rome, Italy
| | - Caterina Grillo
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Laura Cervoni
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Fabio Altieri
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Giulio Nittari
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Margherita Eufemi
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Silvia Chichiarelli
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
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31
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Eggensperger S, Tampé R. The transporter associated with antigen processing: a key player in adaptive immunity. Biol Chem 2016; 396:1059-72. [PMID: 25781678 DOI: 10.1515/hsz-2014-0320] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/02/2015] [Indexed: 01/05/2023]
Abstract
The adaptive immune system co-evolved with sophisticated pathways of antigen processing for efficient clearance of viral infections and malignant transformation. Antigenic peptides are primarily generated by proteasomal degradation and translocated into the lumen of the endoplasmic reticulum (ER) by the transporter associated with antigen processing (TAP). In the ER, peptides are loaded onto major histocompatibility complex I (MHC I) molecules orchestrated by a multisubunit peptide-loading complex (PLC). Peptide-MHC I complexes are targeted to the cell surface for antigen presentation to cytotoxic T cells, which eventually leads to the elimination of virally infected or malignantly transformed cells. Here, we review MHC I mediated antigen processing with a primary focus on the function and structural organization of the heterodimeric ATP-binding cassette (ABC) transporter TAP1/2. We discuss recent data on the molecular transport mechanism of the antigen translocation complex with respect to structural and biochemical information of other ABC exporters. We further summarize how TAP provides a scaffold for the assembly of the macromolecular PLC, thereby coupling peptide translocation with MHC I loading. TAP inhibition by distinct viral evasins highlights the important role of TAP in adaptive immunity.
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32
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Manandhar T, Kunze-Schumacher H, Huyton T, Celik AA, Blasczyk R, Bade-Doeding C. Understanding the obstacle of incompatibility at residue 156 within HLA-B*35 subtypes. Immunogenetics 2016; 68:247-60. [PMID: 26758079 PMCID: PMC4799800 DOI: 10.1007/s00251-015-0896-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 12/23/2015] [Indexed: 01/22/2023]
Abstract
Defining permissive and non-permissive mismatches for transplantation is a demanding challenge. Single mismatches at amino acid (AA) position 156 of human leucocyte antigen (HLA) class I have been described to alter the peptide motif, repertoire, or mode of peptide loading through differential interaction with the peptide-loading complex. Hence, a single mismatch can tip the balance and trigger an immunological reaction. HLA-B*35 subtypes have been described to evade the loading complex, 156 mismatch distinguishing B*35:01 and B*35:08 changes the binding groove sufficiently to alter the sequence features of the selected peptide repertoire. To understand the functional influences of residue 156 in B*35 variants, we analyzed the peptide binding profiles of HLA-B*35:01156Leu, B*35:08156Arg and B*35:62156Trp. The glycoprotein tapasin represents a target for immune evasions and functions within the multimeric peptide-loading complex to stabilize empty class I molecules and promote acquisition of high-affinity peptides. All three B*35 subtypes showed a tapasin-independent mode of peptide acquisition. HLA-B*35-restricted peptides of low- and high-binding affinities were recovered in the presence and absence of tapasin and subsequently sequenced utilizing mass spectrometry. The peptides derived from B*35 variants differ substantially in their features dependent on their mode of recruitment; all peptides were preferentially anchored by Pro at p2 and Tyr, Phe, Leu, or Lys at pΩ. However, the Trp at residue 156 altered the p2 motif to an Ala and restricted the pΩ to a Trp. Our results highlight the importance of understanding the impact of key micropolymorphism and how a single AA mismatch orchestrates the neighboring AAs.
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Affiliation(s)
- Trishna Manandhar
- Hannover Medical School, Institute for Transfusion Medicine, Feodor-Lynen-Str. 5, 30625, Hannover, Germany
| | - Heike Kunze-Schumacher
- Hannover Medical School, Institute for Transfusion Medicine, Feodor-Lynen-Str. 5, 30625, Hannover, Germany
| | - Trevor Huyton
- Hannover Medical School, Institute for Transfusion Medicine, Feodor-Lynen-Str. 5, 30625, Hannover, Germany
| | - Alexander A Celik
- Hannover Medical School, Institute for Transfusion Medicine, Feodor-Lynen-Str. 5, 30625, Hannover, Germany
| | - Rainer Blasczyk
- Hannover Medical School, Institute for Transfusion Medicine, Feodor-Lynen-Str. 5, 30625, Hannover, Germany
| | - Christina Bade-Doeding
- Hannover Medical School, Institute for Transfusion Medicine, Feodor-Lynen-Str. 5, 30625, Hannover, Germany.
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33
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Hermann C, Trowsdale J, Boyle LH. TAPBPR: a new player in the MHC class I presentation pathway. ACTA ACUST UNITED AC 2015; 85:155-66. [PMID: 25720504 DOI: 10.1111/tan.12538] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In order to provide specificity for T cell responses against pathogens and tumours, major histocompatibility complex (MHC) class I molecules present high-affinity peptides at the cell surface to T cells. A key player for peptide loading is the MHC class I-dedicated chaperone tapasin. Recently we discovered a second MHC class I-dedicated chaperone, the tapasin-related protein TAPBPR. Here, we review the major steps in the MHC class I pathway and the TAPBPR data. We discuss the potential function of TAPBPR in the MHC class I pathway and the involvement of this previously uncharacterised protein in human health and disease.
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Affiliation(s)
- C Hermann
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK
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34
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Hermann C, van Hateren A, Trautwein N, Neerincx A, Duriez PJ, Stevanović S, Trowsdale J, Deane JE, Elliott T, Boyle LH. TAPBPR alters MHC class I peptide presentation by functioning as a peptide exchange catalyst. eLife 2015; 4:e09617. [PMID: 26439010 PMCID: PMC4718805 DOI: 10.7554/elife.09617] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/05/2015] [Indexed: 12/29/2022] Open
Abstract
Our understanding of the antigen presentation pathway has recently been enhanced with the identification that the tapasin-related protein TAPBPR is a second major histocompatibility complex (MHC) class I-specific chaperone. We sought to determine whether, like tapasin, TAPBPR can also influence MHC class I peptide selection by functioning as a peptide exchange catalyst. We show that TAPBPR can catalyse the dissociation of peptides from peptide-MHC I complexes, enhance the loading of peptide-receptive MHC I molecules, and discriminate between peptides based on affinity in vitro. In cells, the depletion of TAPBPR increased the diversity of peptides presented on MHC I molecules, suggesting that TAPBPR is involved in restricting peptide presentation. Our results suggest TAPBPR binds to MHC I in a peptide-receptive state and, like tapasin, works to enhance peptide optimisation. It is now clear there are two MHC class I specific peptide editors, tapasin and TAPBPR, intimately involved in controlling peptide presentation to the immune system.
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Affiliation(s)
- Clemens Hermann
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Andy van Hateren
- Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton, United Kingdom
| | - Nico Trautwein
- Department of Immunology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Neerincx
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Patrick J Duriez
- Cancer Research UK Protein Core Facility, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Stefan Stevanović
- Department of Immunology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - John Trowsdale
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Janet E Deane
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Tim Elliott
- Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton, United Kingdom
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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Sokol L, Koelzer VH, Rau TT, Karamitopoulou E, Zlobec I, Lugli A. Loss of tapasin correlates with diminished CD8(+) T-cell immunity and prognosis in colorectal cancer. J Transl Med 2015; 13:279. [PMID: 26310568 PMCID: PMC4551690 DOI: 10.1186/s12967-015-0647-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/20/2015] [Indexed: 11/10/2022] Open
Abstract
Background Tapasin is a crucial component of the major histocompatibility (MHC) class I antigen presentation pathway. Defects in this pathway can lead to tumor immune evasion. The aim of this study was to test whether tapasin expression correlates with CD8+ cytotoxic T lymphocyte (CTL) infiltration of colorectal cancer (CRC) and overall survival. Methods A next-generation tissue microarray (ngTMA) of 198 CRC patients with full clinicopathological information was included in this study. TMA slides were immunostained for tapasin, MHC I and CD8. Marker expression was analyzed with immune-cell infiltration, patient survival and TNM-staging. Results A reduction of tapasin expression strongly correlated with venous invasion (AUC 0.682, OR 2.7, p = 0.002; 95 % CI 1.7–5.0), lymphatic invasion (AUC 0.620, OR 2.0, p = 0.005; 95 % CI 1.3–3.3), distant metastasis (AUC 0.727, OR 2.9, p = 0.004; 95 % CI 1.4–5.9) and an infiltrative tumor border configuration (AUC 0.621, OR 2.2, p = 0.017; 95 % CI 1.2–4.4). Further, tapasin expression was associated with CD8+ CTL infiltration (AUC 0.729, OR 5.4, p < 0.001; 95 % CI 2.6–11), and favorable overall survival (p = 0.004, HR 0.6, 95 % CI 0.42–0.85). Conclusions Consistent with published functional data showing that tapasin promotes antigen presentation, as well as tumor immune recognition and destruction by CD8+ CTLs, a reduction in tapasin expression is associated with tumor progression in CRC. Electronic supplementary material The online version of this article (doi:10.1186/s12967-015-0647-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lena Sokol
- Translational Research Unit (TRU), Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland.
| | - Viktor H Koelzer
- Translational Research Unit (TRU), Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland. .,Clinical Pathology Division, Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland.
| | - Tilman T Rau
- Translational Research Unit (TRU), Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland. .,Clinical Pathology Division, Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland.
| | - Eva Karamitopoulou
- Translational Research Unit (TRU), Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland. .,Clinical Pathology Division, Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland.
| | - Inti Zlobec
- Translational Research Unit (TRU), Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland.
| | - Alessandro Lugli
- Translational Research Unit (TRU), Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland. .,Clinical Pathology Division, Institute of Pathology, University of Bern, Murtenstrasse 31, 3010, Bern, Switzerland.
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Fazakerley DJ, Naghiloo S, Chaudhuri R, Koumanov F, Burchfield JG, Thomas KC, Krycer JR, Prior MJ, Parker BL, Murrow BA, Stöckli J, Meoli CC, Holman GD, James DE. Proteomic Analysis of GLUT4 Storage Vesicles Reveals Tumor Suppressor Candidate 5 (TUSC5) as a Novel Regulator of Insulin Action in Adipocytes. J Biol Chem 2015; 290:23528-42. [PMID: 26240143 PMCID: PMC4583025 DOI: 10.1074/jbc.m115.657361] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Indexed: 01/09/2023] Open
Abstract
Insulin signaling augments glucose transport by regulating glucose transporter 4 (GLUT4) trafficking from specialized intracellular compartments, termed GLUT4 storage vesicles (GSVs), to the plasma membrane. Proteomic analysis of GSVs by mass spectrometry revealed enrichment of 59 proteins in these vesicles. We measured reduced abundance of 23 of these proteins following insulin stimulation and assigned these as high confidence GSV proteins. These included established GSV proteins such as GLUT4 and insulin-responsive aminopeptidase, as well as six proteins not previously reported to be localized to GSVs. Tumor suppressor candidate 5 (TUSC5) was shown to be a novel GSV protein that underwent a 3.7-fold increase in abundance at the plasma membrane in response to insulin. siRNA-mediated knockdown of TUSC5 decreased insulin-stimulated glucose uptake, although overexpression of TUSC5 had the opposite effect, implicating TUSC5 as a positive regulator of insulin-stimulated glucose transport in adipocytes. Incubation of adipocytes with TNFα caused insulin resistance and a concomitant reduction in TUSC5. Consistent with previous studies, peroxisome proliferator-activated receptor (PPAR) γ agonism reversed TNFα-induced insulin resistance. TUSC5 expression was necessary but insufficient for PPARγ-mediated reversal of insulin resistance. These findings functionally link TUSC5 to GLUT4 trafficking, insulin action, insulin resistance, and PPARγ action in the adipocyte. Further studies are required to establish the exact role of TUSC5 in adipocytes.
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Affiliation(s)
- Daniel J Fazakerley
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Sheyda Naghiloo
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Rima Chaudhuri
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Françoise Koumanov
- the Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom
| | - James G Burchfield
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Kristen C Thomas
- From the Charles Perkins Centre, School of Molecular Bioscience, and
| | - James R Krycer
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Matthew J Prior
- The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Ben L Parker
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Beverley A Murrow
- The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Jacqueline Stöckli
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Christopher C Meoli
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and
| | - Geoffrey D Holman
- the Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom
| | - David E James
- From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and School of Medicine, University of Sydney, Sydney, New South Wales 2006, Australia,
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37
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Antigen Translocation Machineries in Adaptive Immunity and Viral Immune Evasion. J Mol Biol 2015; 427:1102-18. [DOI: 10.1016/j.jmb.2014.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 09/04/2014] [Accepted: 09/05/2014] [Indexed: 11/23/2022]
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38
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Schwertassek U, Haque A, Krishnan N, Greiner R, Weingarten L, Dick TP, Tonks NK. Reactivation of oxidized PTP1B and PTEN by thioredoxin 1. FEBS J 2014; 281:3545-58. [PMID: 24976139 DOI: 10.1111/febs.12898] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/02/2014] [Accepted: 06/26/2014] [Indexed: 11/28/2022]
Abstract
UNLABELLED The transient inactivation of protein phosphatases contributes to the efficiency and temporal control of kinase-dependent signal transduction. In particular, members of the protein tyrosine phosphatase family are known to undergo reversible oxidation of their active site cysteine. The thiol oxidation step requires activation of colocalized NADPH oxidases and is mediated by locally produced reactive oxygen species, in particular H2 O2 . How oxidized phosphatases are returned to the reduced active state is less well studied. Both major thiol reductive systems, the thioredoxin and the glutathione systems, have been implicated in the reactivation of phosphatases. Here, we show that the protein tyrosine phosphatase PTP1B and the dual-specificity phosphatase PTEN are preferentially reactivated by the thioredoxin system. We show that inducible depletion of thioredoxin 1(TRX1) slows PTEN reactivation in intact living cells. Finally, using a mechanism-based trapping approach, we demonstrate direct thiol disulphide exchange between the active sites of thioredoxin and either phosphatase. The application of thioredoxin trapping mutants represents a complementary approach to direct assays of PTP oxidation in elucidating the significance of redox regulation of PTP function in the control of cell signaling. STRUCTURED DIGITAL ABSTRACT TRX1 physically interacts with PTP1B by anti tag coimmunoprecipitation (1, 2).
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Leonhardt RM, Abrahimi P, Mitchell SM, Cresswell P. Three tapasin docking sites in TAP cooperate to facilitate transporter stabilization and heterodimerization. THE JOURNAL OF IMMUNOLOGY 2014; 192:2480-94. [PMID: 24501197 DOI: 10.4049/jimmunol.1302637] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The TAP translocates peptide Ags into the lumen of the endoplasmic reticulum for loading onto MHC class I molecules. MHC class I acquires its peptide cargo in the peptide loading complex, an oligomeric complex that the chaperone tapasin organizes by bridging TAP to MHC class I and recruiting accessory molecules such as ERp57 and calreticulin. Three tapasin binding sites on TAP have been described, two of which are located in the N-terminal domains of TAP1 and TAP2. The third binding site is present in the core transmembrane (TM) domain of TAP1 and is used only by the unassembled subunits. Tapasin is required to promote TAP stability, but through which binding site(s) it is acting is unknown. In particular, the role of tapasin binding to the core TM domain of TAP1 single chains is mysterious because this interaction is lost upon TAP2 association. In this study, we map the respective binding site in TAP1 to the polar face of the amphipathic TM helix TM9 and identify key residues that are essential to establish the interaction. We find that this interaction is dispensable for the peptide transport function but essential to achieve full stability of human TAP1. The interaction is also required for proper heterodimerization of the transporter. Based on similar results obtained using TAP mutants that lack tapasin binding to either N-terminal domain, we conclude that all three tapasin-binding sites in TAP cooperate to achieve high transporter stability and efficient heterodimerization.
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Abstract
The mammalian immune system has evolved to display peptides derived from microbial antigens to immune effector cells. Liberated from the intact antigens through distinct proteolytic mechanisms, these peptides are subsequently transported to the cell surface while bound to chaperone-like receptors known as major histocompatibility complex molecules. These complexes are then scrutinized by T-cells that express receptors with specificity for specific major histocompatibility complex-peptide complexes. In normal uninfected cells, this process of antigen processing and presentation occurs continuously, with the resultant array of self-antigen-derived peptides displayed on the surface of these cells. Changes in this cellular peptide array alert the immune system to changes in the intracellular environment that may be associated with infection, oncogenesis or other abnormal cellular processes, resulting in a cascade of events that result in the elimination of the abnormal cell. Since peptides play such an essential role in informing the immune system of infection with viral or microbial pathogens and the transformation of cells in malignancy, the tools of proteomics, in particular mass spectrometry, are ideally suited to study these immune responses at a molecular level. Recent advances in studies of immune responses that have utilized mass spectrometry and associated technologies are reviewed. The authors gaze into the future and look at current challenges and where proteomics will impact in immunology over the next 5 years.
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Affiliation(s)
- Nicholas A Williamson
- The University of Melbourne, Department of Biochemistry & Molecular Biology, The Bio21 Molecular Science & Biotechnology Institute, 3010, Victoria, Australia.
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41
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Sokolowski M, deHaro D, Christian CM, Kines KJ, Belancio VP. Characterization of L1 ORF1p self-interaction and cellular localization using a mammalian two-hybrid system. PLoS One 2013; 8:e82021. [PMID: 24324740 PMCID: PMC3852968 DOI: 10.1371/journal.pone.0082021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/23/2013] [Indexed: 12/31/2022] Open
Abstract
Long INterspersed Element-1 (LINE-1, L1) is an active retrotransposon that mobilizes using a ribonucleoprotein particle (RNP) intermediate composed of the full-length bicistronic L1 mRNA and the two proteins (ORF1p and ORF2p) encoded by that mRNA. ORF1p and ORF2p demonstrate cis-preference for their encoding mRNA. Previous studies of ORF1p, purified from bacterial and insect cells demonstrated that this protein forms trimers in vitro. While valuable for understanding ORF1p function, these in vitro approaches do not provide any information on ORF1p self-interaction in the context of mammalian cells. We used a mammalian two-hybrid (M2H) system in order to study L1 ORF1p self-interaction in human and mouse cells. We demonstrate that the M2H system successfully detects human and mouse ORF1p self-interactions in transiently transfected mammalian cells. We also generated mouse and human ORF1p-specific antibodies to characterize the expression of ORF1p fusion proteins used in the M2H system. Using these antibodies, we demonstrate that ORF1p interaction in trans leads to the formation of heterodimers that are expected to produce a positive signal in the M2H system. Although the role for L1 ORF1p cis-preference in L1 mobilization is established, the impact of ability of ORF1pto interact in trans on the L1 replication cycle is not known. Furthermore, western blot analysis of ORF1p generated by a full-length L1, wild type ORF1, or a codon-optimized ORF1 expression vector is detected in the nucleus. In contrast, the addition of a tag to the N-terminus of the mouse and human ORF1 proteins can significantly alter the subcellular localization in a tag-specific manner. These data support that nuclear localization of ORF1p may contribute to L1 (and potentially the SINE Alu) RNP nuclear access in the host cell.
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Affiliation(s)
- Mark Sokolowski
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, Louisiana, United States of America
| | - Dawn deHaro
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, Louisiana, United States of America
| | - Claiborne M. Christian
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, Louisiana, United States of America
| | - Kristine J. Kines
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, Louisiana, United States of America
| | - Victoria P. Belancio
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, Louisiana, United States of America
- * E-mail:
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42
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Hermann C, Strittmatter LM, Deane JE, Boyle LH. The binding of TAPBPR and Tapasin to MHC class I is mutually exclusive. THE JOURNAL OF IMMUNOLOGY 2013; 191:5743-50. [PMID: 24163410 DOI: 10.4049/jimmunol.1300929] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The loading of peptide Ags onto MHC class I molecules is a highly controlled process in which the MHC class I-dedicated chaperone tapasin is a key player. We recently identified a tapasin-related molecule, TAPBPR, as an additional component in the MHC class I Ag-presentation pathway. In this study, we show that the amino acid residues important for tapasin to interact with MHC class I are highly conserved on TAPBPR. We identify specific residues in the N-terminal and C-terminal domains of TAPBPR involved in associating with MHC class I. Furthermore, we demonstrate that residues on MHC class I crucial for its association with tapasin, such as T134, are also essential for its interaction with TAPBPR. Taken together, the data indicate that TAPBPR and tapasin bind in a similar orientation to the same face of MHC class I. In the absence of tapasin, the association of MHC class I with TAPBPR is increased. However, in the absence of TAPBPR, the interaction between MHC class I and tapasin does not increase. In light of our findings, previous data determining the function of tapasin in the MHC class I Ag-processing and presentation pathway must be re-evaluated.
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Affiliation(s)
- Clemens Hermann
- Department of Pathology, Cambridge Institute of Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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43
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Pinto RD, Moreira AR, Pereira PJB, dos Santos NMS. Two thioredoxin-superfamily members from sea bass (Dicentrarchus labrax, L.): characterization of PDI (PDIA1) and ERp57 (PDIA3). FISH & SHELLFISH IMMUNOLOGY 2013; 35:1163-1175. [PMID: 23880452 DOI: 10.1016/j.fsi.2013.07.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 07/03/2013] [Accepted: 07/14/2013] [Indexed: 06/02/2023]
Abstract
PDI (PDIA1) and ERp57 (PDIA3), members of the PDI family and of the thioredoxin (Trx) superfamily, are multifunctional proteins with wide physiological roles and have been implicated in several pathologies. Importantly, they are both involved in the MHC class I antigen presentation pathway. This paper reports the isolation and characterization of full cDNA and genomic clones from sea bass (Dicentrarchus labrax, L.) PDI (Dila-PDI) and ERp57 (Dila-ERp57). The genes are ~12.4 and ~7.1 kb long, originating 2155 and 2173 bp transcripts and encoding 497 and 484 amino acids mature proteins, for Dila-PDI and -ERp57, respectively. The PDI gene consists of eleven exons and ERp57 of thirteen. As described in other species, both molecules are composed of four Trx-like domains (abb'a') followed by a C-terminal tail, retaining two CGHC active sites and an ER-signalling sequence, suggestive of a conserved function. Additionally, three-dimensional homology models further support Dila-PDI and Dila-ERp57 as orthologs of mammalian PDI and ERp57, respectively. Finally, high similarity is observed to their vertebrate counterparts (>69% identity), especially among the few ones from closely related teleosts (>79% identity). Hence, these results provide relevant primary data and will enable further studies to clarify the roles of PDI and ERp57 in European sea bass immunity.
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Affiliation(s)
- Rute D Pinto
- Fish Immunology and Vaccinology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
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44
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van Hateren A, Carter R, Bailey A, Kontouli N, Williams AP, Kaufman J, Elliott T. A mechanistic basis for the co-evolution of chicken tapasin and major histocompatibility complex class I (MHC I) proteins. J Biol Chem 2013; 288:32797-32808. [PMID: 24078633 DOI: 10.1074/jbc.m113.474031] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MHC class I molecules display peptides at the cell surface to cytotoxic T cells. The co-factor tapasin functions to ensure that MHC I becomes loaded with high affinity peptides. In most mammals, the tapasin gene appears to have little sequence diversity and few alleles and is located distal to several classical MHC I loci, so tapasin appears to function in a universal way to assist MHC I peptide loading. In contrast, the chicken tapasin gene is tightly linked to the single dominantly expressed MHC I locus and is highly polymorphic and moderately diverse in sequence. Therefore, tapasin-assisted loading of MHC I in chickens may occur in a haplotype-specific way, via the co-evolution of chicken tapasin and MHC I. Here we demonstrate a mechanistic basis for this co-evolution, revealing differences in the ability of two chicken MHC I alleles to bind and release peptides in the presence or absence of tapasin, where, as in mammals, efficient self-loading is negatively correlated with tapasin-assisted loading. We found that a polymorphic residue in the MHC I α3 domain thought to bind tapasin influenced both tapasin function and intrinsic peptide binding properties. Differences were also evident between the MHC alleles in their interactions with tapasin. Last, we show that a mismatched combination of tapasin and MHC alleles exhibit significantly impaired MHC I maturation in vivo and that polymorphic MHC residues thought to contact tapasin influence maturation efficiency. Collectively, this supports the possibility that tapasin and BF2 proteins have co-evolved, resulting in allele-specific peptide loading in vivo.
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Affiliation(s)
- Andy van Hateren
- From the Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, United Kingdom,; the Institute for Animal Health, Compton RG20 7NN, United Kingdom
| | - Rachel Carter
- From the Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Alistair Bailey
- From the Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Nasia Kontouli
- From the Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Anthony P Williams
- From the Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Jim Kaufman
- the Institute for Animal Health, Compton RG20 7NN, United Kingdom; the Departments of Pathology and Veterinary Medicine, University of Cambridge, Cambridge CB2 1QP, United Kingdom.
| | - Tim Elliott
- From the Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, United Kingdom,.
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Kanaseki T, Lind KC, Escobar H, Nagarajan N, Reyes-Vargas E, Rudd B, Rockwood AL, Van Kaer L, Sato N, Delgado JC, Shastri N. ERAAP and tapasin independently edit the amino and carboxyl termini of MHC class I peptides. THE JOURNAL OF IMMUNOLOGY 2013; 191:1547-55. [PMID: 23863903 DOI: 10.4049/jimmunol.1301043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Effective CD8(+) T cell responses depend on presentation of a stable peptide repertoire by MHC class I (MHC I) molecules on the cell surface. The overall quality of peptide-MHC I complexes (pMHC I) is determined by poorly understood mechanisms that generate and load peptides with appropriate consensus motifs onto MHC I. In this article, we show that both tapasin (Tpn), a key component of the peptide loading complex, and the endoplasmic reticulum aminopeptidase associated with Ag processing (ERAAP) are quintessential editors of distinct structural features of the peptide repertoire. We carried out reciprocal immunization of wild-type mice with cells from Tpn- or ERAAP-deficient mice. Specificity analysis of T cell responses showed that absence of Tpn or ERAAP independently altered the peptide repertoire by causing loss as well as gain of new pMHC I. Changes in amino acid sequences of MHC-bound peptides revealed that ERAAP and Tpn, respectively, defined the characteristic amino and carboxy termini of canonical MHC I peptides. Thus, the optimal pMHC I repertoire is produced by two distinct peptide editing steps in the endoplasmic reticulum.
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Affiliation(s)
- Takayuki Kanaseki
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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Leone P, Shin EC, Perosa F, Vacca A, Dammacco F, Racanelli V. MHC class I antigen processing and presenting machinery: organization, function, and defects in tumor cells. J Natl Cancer Inst 2013; 105:1172-87. [PMID: 23852952 DOI: 10.1093/jnci/djt184] [Citation(s) in RCA: 357] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The surface presentation of peptides by major histocompatibility complex (MHC) class I molecules is critical to all CD8(+) T-cell adaptive immune responses, including those against tumors. The generation of peptides and their loading on MHC class I molecules is a multistep process involving multiple molecular species that constitute the so-called antigen processing and presenting machinery (APM). The majority of class I peptides begin as proteasome degradation products of cytosolic proteins. Once transported into the endoplasmic reticulum by TAP (transporter associated with antigen processing), peptides are not bound randomly by class I molecules but are chosen by length and sequence, with peptidases editing the raw peptide pool. Aberrations in APM genes and proteins have frequently been observed in human tumors and found to correlate with relevant clinical variables, including tumor grade, tumor stage, disease recurrence, and survival. These findings support the idea that APM defects are immune escape mechanisms that disrupt the tumor cells' ability to be recognized and killed by tumor antigen-specific cytotoxic CD8(+) T cells. Detailed knowledge of APM is crucial for the optimization of T cell-based immunotherapy protocols.
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Affiliation(s)
- Patrizia Leone
- Department of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy
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47
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The MHC I loading complex: a multitasking machinery in adaptive immunity. Trends Biochem Sci 2013; 38:412-20. [PMID: 23849087 DOI: 10.1016/j.tibs.2013.06.003] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/31/2013] [Accepted: 06/03/2013] [Indexed: 11/22/2022]
Abstract
Recognition and elimination of virally or malignantly transformed cells are pivotal tasks of the adaptive immune system. For efficient immune detection, snapshots of the cellular proteome are presented as epitopes on major histocompatibility complex class I (MHC I) molecules for recognition by cytotoxic T cells. Knowledge about the track from the equivocal protein to the presentation of antigenic peptides has greatly expanded, leading to an astonishingly elaborate understanding of the MHC I peptide loading pathway. Here, we summarize the current view on this complex process, which involves ABC transporters, proteases, chaperones, and endoplasmic reticulum (ER) quality control. The contribution of individual proteins and subcomplexes is discussed, with a focus on the architecture and dynamics of the key player in the pathway, the peptide-loading complex (PLC).
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48
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Beutler N, Hauka S, Niepel A, Kowalewski DJ, Uhlmann J, Ghanem E, Erkelenz S, Wiek C, Hanenberg H, Schaal H, Stevanović S, Springer S, Momburg F, Hengel H, Halenius A. A natural tapasin isoform lacking exon 3 modifies peptide loading complex function. Eur J Immunol 2013; 43:1459-69. [DOI: 10.1002/eji.201242725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 02/01/2013] [Accepted: 03/15/2013] [Indexed: 02/06/2023]
Affiliation(s)
- Nele Beutler
- Institute for Virology; Heinrich-Heine-University Düsseldorf; Düsseldorf; Germany
| | - Sebastian Hauka
- Institute for Virology; Heinrich-Heine-University Düsseldorf; Düsseldorf; Germany
| | - Alexandra Niepel
- Institute for Virology; Heinrich-Heine-University Düsseldorf; Düsseldorf; Germany
| | | | - Julia Uhlmann
- Institute for Virology; Heinrich-Heine-University Düsseldorf; Düsseldorf; Germany
| | - Esther Ghanem
- Department of Biochemistry and Cell Biology; Jacobs University Bremen; Bremen; Germany
| | - Steffen Erkelenz
- Institute for Virology; Heinrich-Heine-University Düsseldorf; Düsseldorf; Germany
| | - Constanze Wiek
- Department of Otorhinolaryngology; Heinrich-Heine-University Düsseldorf; Düsseldorf; Germany
| | | | - Heiner Schaal
- Institute for Virology; Heinrich-Heine-University Düsseldorf; Düsseldorf; Germany
| | - Stefan Stevanović
- Department of Immunology; Institute for Cell Biology; University of Tübingen; Tübingen; Germany
| | - Sebastian Springer
- Department of Biochemistry and Cell Biology; Jacobs University Bremen; Bremen; Germany
| | - Frank Momburg
- Division of Translational Immunology (D015); German Cancer Research Center (DKFZ); Heidelberg; Germany
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49
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Abstract
T cell recognition of antigen-presenting cells depends on their expression of a spectrum of peptides bound to major histocompatibility complex class I (MHC-I) and class II (MHC-II) molecules. Conversion of antigens from pathogens or transformed cells into MHC-I- and MHC-II-bound peptides is critical for mounting protective T cell responses, and similar processing of self proteins is necessary to establish and maintain tolerance. Cells use a variety of mechanisms to acquire protein antigens, from translation in the cytosol to variations on the theme of endocytosis, and to degrade them once acquired. In this review, we highlight the aspects of MHC-I and MHC-II biosynthesis and assembly that have evolved to intersect these pathways and sample the peptides that are produced.
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Affiliation(s)
- Janice S Blum
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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50
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Abstract
The stability of the MHC (major histocompatibility complex) class I peptide repertoire is optimized during assembly in the endoplasmic reticulum (ER) and depends on the collective function of components of the peptide-loading complex (PLC). The chaperone-like molecule tapasin is the cornerstone of this complex and acts directly on the MHC class I molecule to promote high-affinity peptide loading. Optimal tapasin activity, however, relies on the ability of ERp57 and calreticulin, two proteins involved in general ER glycoprotein folding, to bridge and thereby stabilize its otherwise weak interaction with the MHC class I heavy chain. Here, we describe methods for the recombinant expression of soluble components of the PLC specifically tailored to generate the post-translational modifications required to support subcomplex assembly in vitro. Using recombinant MHC class I molecules bearing monoglucosylated N-linked glycans, calreticulin, and disulfide-linked tapasin/ERp57 heterodimers, this soluble PLC subcomplex can be employed to study the mechanism of peptide loading or the principles governing peptide selection for particular MHC class I alleles.
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Affiliation(s)
- Pamela A Wearsch
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Peter Cresswell
- Department of Immunobiology and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, USA.
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