1
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Luo JH, Wang FX, Zhao JW, Yang CL, Rong SJ, Lu WY, Chen QJ, Zhou Q, Xiao J, Wang YN, Luo X, Li Y, Song DN, Chen C, Zhang CL, Chen SH, Yang P, Xiong F, Yu QL, Zhang S, Liu SW, Sun F, Wang CY. PDIA3 defines a novel subset of adipose macrophages to exacerbate the development of obesity and metabolic disorders. Cell Metab 2024; 36:2262-2280.e5. [PMID: 39293433 DOI: 10.1016/j.cmet.2024.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 06/04/2024] [Accepted: 08/26/2024] [Indexed: 09/20/2024]
Abstract
Adipose tissue macrophages (ATMs) play important roles in maintaining adipose tissue homeostasis and orchestrating metabolic inflammation. Given the extensive functional heterogeneity and phenotypic plasticity of ATMs, identification of the authentically pathogenic ATM subpopulation under obese setting is thus necessitated. Herein, we performed single-nucleus RNA sequencing (snRNA-seq) and unraveled a unique maladaptive ATM subpopulation defined as ATF4hiPDIA3hiACSL4hiCCL2hi inflammatory and metabolically activated macrophages (iMAMs), in which PDIA3 is required for the maintenance of their migratory and pro-inflammatory properties. Mechanistically, ATF4 serves as a metabolic stress sensor to transcribe PDIA3, which then imposes a redox control on RhoA activity and strengthens the pro-inflammatory and migratory properties of iMAMs through RhoA-YAP signaling. Administration of Pdia3 small interfering RNA (siRNA)-loaded liposomes effectively repressed adipose inflammation and high-fat diet (HFD)-induced obesity. Together, our data support that strategies aimed at targeting iMAMs by suppressing PDIA3 expression or activity could be a viable approach against obesity and metabolic disorders in clinical settings.
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Affiliation(s)
- Jia-Hui Luo
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fa-Xi Wang
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jia-Wei Zhao
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chun-Liang Yang
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shan-Jie Rong
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wan-Ying Lu
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi-Jie Chen
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qing Zhou
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jun Xiao
- Department of Thyroid and Breast Surgery, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Ya-Nan Wang
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Urology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Xi Luo
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yang Li
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dan-Ni Song
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cai Chen
- Department of Endocrinology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cheng-Liang Zhang
- Department of Pharmacy, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Su-Hua Chen
- Department of Obstetrics and Gynecology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ping Yang
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Xiong
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi-Lin Yu
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shu Zhang
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shi-Wei Liu
- Shanxi Bethune Hospital, Shanxi Academy of Medical Science, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, The Key Laboratory of Endocrine and Metabolic Diseases of Shanxi Province, Taiyuan, China
| | - Fei Sun
- Department of Respiratory and Critical Care Medicine, The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Cong-Yi Wang
- Shanxi Bethune Hospital, Shanxi Academy of Medical Science, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, The Key Laboratory of Endocrine and Metabolic Diseases of Shanxi Province, Taiyuan, China; The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Tongji Hospital Research Building, Wuhan, China.
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2
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Brunnberg J, Barends M, Frühschulz S, Winter C, Battin C, de Wet B, Cole DK, Steinberger P, Tampé R. Dual role of the peptide-loading complex as proofreader and limiter of MHC-I presentation. Proc Natl Acad Sci U S A 2024; 121:e2321600121. [PMID: 38771881 PMCID: PMC11145271 DOI: 10.1073/pnas.2321600121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/17/2024] [Indexed: 05/23/2024] Open
Abstract
Antigen presentation via major histocompatibility complex class I (MHC-I) molecules is essential for surveillance by the adaptive immune system. Central to this process is the peptide-loading complex (PLC), which translocates peptides from the cytosol to the endoplasmic reticulum and catalyzes peptide loading and proofreading of peptide-MHC-I (pMHC-I) complexes. Despite its importance, the impact of individual PLC components on the presented pMHC-I complexes is still insufficiently understood. Here, we used stoichiometrically defined antibody-nanobody complexes and engineered soluble T cell receptors (sTCRs) to quantify different MHC-I allomorphs and defined pMHC-I complexes, respectively. Thereby, we uncovered distinct effects of individual PLC components on the pMHC-I surface pool. Knockouts of components of the PLC editing modules, namely tapasin, ERp57, or calreticulin, changed the MHC-I surface composition to a reduced proportion of HLA-A*02:01 presentation compensated by a higher ratio of HLA-B*40:01 molecules. Intriguingly, these knockouts not only increased the presentation of suboptimally loaded HLA-A*02:01 complexes but also elevated the presentation of high-affinity peptides overexpressed in the cytosol. Our findings suggest that the components of the PLC editing module serve a dual role, acting not only as peptide proofreaders but also as limiters for abundant peptides. This dual function ensures the presentation of a broad spectrum of antigenic peptides.
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Affiliation(s)
- Jamina Brunnberg
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Martina Barends
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Stefan Frühschulz
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Christian Winter
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Claire Battin
- Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna1090, Austria
| | - Ben de Wet
- Immunocore Ltd., AbingdonOX14 4RY, United Kingdom
| | | | - Peter Steinberger
- Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna1090, Austria
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main60438, Germany
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3
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Czaja AJ. Introducing Molecular Chaperones into the Causality and Prospective Management of Autoimmune Hepatitis. Dig Dis Sci 2023; 68:4098-4116. [PMID: 37755606 PMCID: PMC10570239 DOI: 10.1007/s10620-023-08118-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023]
Abstract
Molecular chaperones influence the immunogenicity of peptides and the activation of effector T cells, and their pathogenic roles in autoimmune hepatitis are unclear. Heat shock proteins are pivotal in the processing and presentation of peptides that activate CD8+ T cells. They can also induce regulatory B and T cells and promote immune tolerance. Tapasin and the transporter associated with antigen processing-binding protein influence the editing and loading of high-affinity peptides for presentation by class I molecules of the major histocompatibility complex. Their over-expression could enhance the autoimmune response, and their deficiency could weaken it. The lysosome-associated membrane protein-2a isoform in conjunction with heat shock cognate 70 supports the importation of cytosolic proteins into lysosomes. Chaperone-mediated autophagy can then process the peptides for activation of CD4+ T cells. Over-expression of autophagy in T cells may also eliminate negative regulators of their activity. The human leukocyte antigen B-associated transcript three facilitates the expression of class II peptide receptors, inhibits T cell apoptosis, prevents T cell exhaustion, and sustains the immune response. Immunization with heat shock proteins has induced immune tolerance in experimental models and humans with autoimmune disease by inducing regulatory T cells. Therapeutic manipulation of other molecular chaperones may promote T cell exhaustion and induce tolerogenic dendritic cells. In conclusion, molecular chaperones constitute an under-evaluated family of ancillary proteins that could affect the occurrence, severity, and outcome of autoimmune hepatitis. Clarification of their contributions to the immune mechanisms and clinical activity of autoimmune hepatitis could have therapeutic implications.
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Affiliation(s)
- Albert J Czaja
- Mayo Clinic College of Medicine and Science, 200 First Street S.W., Rochester, MN, 55905, USA.
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4
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van Hateren A, Elliott T. Visualising tapasin- and TAPBPR-assisted editing of major histocompatibility complex class-I immunopeptidomes. Curr Opin Immunol 2023; 83:102340. [PMID: 37245412 DOI: 10.1016/j.coi.2023.102340] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 04/21/2023] [Accepted: 04/21/2023] [Indexed: 05/30/2023]
Abstract
Which peptides are selected for presentation by major histocompatibility complex class-I (MHC-I) molecules is a key determinant of successful immune responses. Peptide selection is co-ordinated by the tapasin and TAP Binding PRotein (TAPBPR) proteins, which ensure MHC-I molecules preferentially acquire high-affinity-binding peptides. New structural analyses have offered insight into how tapasin achieves this function within the peptide-loading complex (PLC) (comprising the Transporter associated with Antigen Presentation (TAP) peptide transporter, tapasin-ERp57, MHC-I and calreticulin), and how TAPBPR performs a peptide editing function independently of other molecules. The new structures reveal nuances in how tapasin and TAPBPR interact with MHC-I, and how calreticulin and ERp57 complement tapasin to exploit the plasticity of MHC-I molecules to achieve peptide editing.
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Affiliation(s)
- Andy van Hateren
- Institute for Life Sciences and Centre for Cancer Immunology, Faculty of Medicine, University of Southampton, Building 85, Southampton SO17 1BJ, UK
| | - Tim Elliott
- Centre for Immuno-oncology and CAMS-Oxford Institute, Nuffield Department of Medicine, University of Oxford, Old Road Campus, Headington, Oxford OX3 7BN, UK.
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5
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Fernandes Â, Azevedo CM, Silva MC, Faria G, Dantas CS, Vicente MM, Pinho SS. Glycans as shapers of tumour microenvironment: A sweet driver of T-cell-mediated anti-tumour immune response. Immunology 2023; 168:217-232. [PMID: 35574724 DOI: 10.1111/imm.13494] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/22/2022] [Indexed: 01/17/2023] Open
Abstract
Essentially all cells are covered with a dense coat of different glycan structures/sugar chains, giving rise to the so-called glycocalyx. Changes in cellular glycosylation are a hallmark of cancer, affecting most of the pathophysiological processes associated with malignant transformation, including tumour immune responses. Glycans are chief macromolecules that define T-cell development, differentiation, fate, activation and signalling. Thus, the diversity of glycans expressed at the surface of T cells constitutes a fundamental molecular interface with the microenvironment by regulating the bilateral interactions between T-cells and cancer cells, fine-tuning the anti-tumour immune response. In this review, we will introduce the power of glycans as orchestrators of T-cell-mediated immune response in physiological conditions and in cancer. We discuss how glycans modulate the glyco-metabolic landscape in the tumour microenvironment, and whether glycans can synergize with immunotherapy as a way of rewiring T-cell effector functions against cancer cells.
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Affiliation(s)
- Ângela Fernandes
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal
| | - Catarina M Azevedo
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal.,School of Medicine and Biological Sciences (ICBAS), University of Porto, Porto, Portugal
| | - Mariana C Silva
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal.,School of Medicine and Biological Sciences (ICBAS), University of Porto, Porto, Portugal
| | - Guilherme Faria
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Carolina S Dantas
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal.,School of Medicine and Biological Sciences (ICBAS), University of Porto, Porto, Portugal
| | - Manuel M Vicente
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal.,School of Medicine and Biological Sciences (ICBAS), University of Porto, Porto, Portugal
| | - Salomé S Pinho
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal.,School of Medicine and Biological Sciences (ICBAS), University of Porto, Porto, Portugal.,Faculty of Medicine, University of Porto, Porto, Portugal
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6
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Molecular basis of MHC I quality control in the peptide loading complex. Nat Commun 2022; 13:4701. [PMID: 35948544 PMCID: PMC9365787 DOI: 10.1038/s41467-022-32384-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 07/28/2022] [Indexed: 11/30/2022] Open
Abstract
Major histocompatibility complex class I (MHC I) molecules are central to adaptive immunity. Their assembly, epitope selection, and antigen presentation are controlled by the MHC I glycan through a sophisticated network of chaperones and modifying enzymes. However, the mechanistic integration of the corresponding processes remains poorly understood. Here, we determine the multi-chaperone-client interaction network of the peptide loading complex (PLC) and report the PLC editing module structure by cryogenic electron microscopy at 3.7 Å resolution. Combined with epitope-proofreading studies of the PLC in near-native lipid environment, these data show that peptide-receptive MHC I molecules are stabilized by multivalent chaperone interactions including the calreticulin-engulfed mono-glucosylated MHC I glycan, which only becomes accessible for processing by α-glucosidase II upon loading of optimal epitopes. Our work reveals allosteric coupling between peptide-MHC I assembly and glycan processing. This inter-process communication defines the onset of an adaptive immune response and provides a prototypical example of the tightly coordinated events in endoplasmic reticulum quality control. The immune system monitors the health status of cells by surveilling fragments of foreign molecules from invaders presented on MHC I complexes at the cell surface. Here, the authors investigate the sequence of events of MHC I assembly and quality control cycle.
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7
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Margulies DH, Taylor DK, Jiang J, Boyd LF, Ahmad J, Mage MG, Natarajan K. Chaperones and Catalysts: How Antigen Presentation Pathways Cope With Biological Necessity. Front Immunol 2022; 13:859782. [PMID: 35464465 PMCID: PMC9022212 DOI: 10.3389/fimmu.2022.859782] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Immune recognition by T lymphocytes and natural killer (NK) cells is in large part dependent on the identification of cell surface MHC molecules bearing peptides generated from either endogenous (MHC I) or exogenous (MHC II) dependent pathways. This review focuses on MHC I molecules that coordinately fold to bind self or foreign peptides for such surface display. Peptide loading occurs in an antigen presentation pathway that includes either the multimolecular peptide loading complex (PLC) or a single chain chaperone/catalyst, TAP binding protein, related, TAPBPR, that mimics a key component of the PLC, tapasin. Recent structural and dynamic studies of TAPBPR reveal details of its function and reflect on mechanisms common to tapasin. Regions of structural conservation among species suggest that TAPBPR and tapasin have evolved to satisfy functional complexities demanded by the enormous polymorphism of MHC I molecules. Recent studies suggest that these two chaperone/catalysts exploit structural flexibility and dynamics to stabilize MHC molecules and facilitate peptide loading.
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Affiliation(s)
- David H Margulies
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Daniel K Taylor
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Jiansheng Jiang
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Lisa F Boyd
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Javeed Ahmad
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Michael G Mage
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Kannan Natarajan
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
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8
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Mercier R, LaPointe P. The role of cellular proteostasis in anti-tumor immunity. J Biol Chem 2022; 298:101930. [PMID: 35421375 PMCID: PMC9108985 DOI: 10.1016/j.jbc.2022.101930] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/21/2022] [Accepted: 03/31/2022] [Indexed: 12/25/2022] Open
Abstract
Immune checkpoint blockade therapy is perhaps the most important development in cancer treatment in recent memory. It is based on decades of investigation into the biology of immune cells and the role of the immune system in controlling cancer growth. While the molecular circuitry that governs the immune system in general - and anti-tumor immunity in particular - is intensely studied, far less attention has been paid to the role of cellular stress in this process. Proteostasis, intimately linked to cell stress responses, refers to the dynamic regulation of the cellular proteome and is maintained through a complex network of systems that govern the synthesis, folding, and degradation of proteins in the cell. Disruption of these systems can result in the loss of protein function, altered protein function, the formation of toxic aggregates, or pathologies associated with cell stress. However, the importance of proteostasis extends beyond its role in maintaining proper protein function; proteostasis governs how tolerant cells may be to mutations in protein coding genes and the overall half-life of proteins. Such gene expression changes may be associated with human diseases including neurodegenerative diseases, metabolic disease, and cancer and manifest at the protein level against the backdrop of the proteostasis network in any given cellular environment. In this review, we focus on the role of proteostasis in regulating immune responses against cancer as well the role of proteostasis in determining immunogenicity of cancer cells.
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Affiliation(s)
- Rebecca Mercier
- Department of Cell Biology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Paul LaPointe
- Department of Cell Biology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada.
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9
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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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10
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Ilca FT, Boyle LH. The glycosylation status of MHC class I molecules impacts their interactions with TAPBPR. Mol Immunol 2021; 139:168-176. [PMID: 34543843 PMCID: PMC8524320 DOI: 10.1016/j.molimm.2021.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/16/2021] [Accepted: 09/11/2021] [Indexed: 11/20/2022]
Abstract
Glycosylation plays a crucial role in the folding, structure, quality control and trafficking of glycoproteins. Here, we explored whether the glycosylation status of MHC class I (MHC-I) molecules impacts their affinity for the peptide editor, TAPBPR. We demonstrate that the interaction between TAPBPR and MHC-I is stronger when MHC-I lacks a glycan. Subsequently, TAPBPR can dissociate peptides, even those of high affinity, more easily from non-glycosylated MHC-I compared to their glycosylated counterparts. In addition, TAPBPR is more resistant to peptide-mediated allosteric release from non-glycosylated MHC-I compared to species with a glycan attached. Consequently, we find the glycosylation status of HLA-A*68:02, -A*02:01 and -B*27:05 influences their ability to undergo TAPBPR-mediated peptide exchange. The discovery that the glycan attached to MHC-I significantly influences the affinity of their interactions with TAPBPR has important implications, on both an experimental level and in a biological context.
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Affiliation(s)
- F Tudor Ilca
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK.
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11
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Hoek M, Demmers LC, Wu W, Heck AJR. Allotype-Specific Glycosylation and Cellular Localization of Human Leukocyte Antigen Class I Proteins. J Proteome Res 2021; 20:4518-4528. [PMID: 34415762 PMCID: PMC8419865 DOI: 10.1021/acs.jproteome.1c00466] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
![]()
Presentation of antigens
by human leukocyte antigen (HLA) complexes
at the cell surface is a key process in the immune response. The α-chain,
containing the peptide-binding groove, is one of the most polymorphic
proteins in the proteome. All HLA class I α-chains carry a conserved
N-glycosylation site, but little is known about its nature and function.
Here, we report an in-depth characterization of N-glycosylation features
of HLA class I molecules. We observe that different HLA-A α-chains
carry similar glycosylation, distinctly different from the HLA-B,
HLA-C, and HLA-F α-chains. Although HLA-A displays the broadest
variety of glycan characteristics, HLA-B α-chains carry mostly
mature glycans, and HLA-C and HLA-F α-chains carry predominantly
high-mannose glycans. We expected these glycosylation features to
be directly linked to cellular localization of the HLA complexes.
Indeed, analyzing HLA class I complexes from crude plasma and inner
membrane-enriched fractions confirmed that most HLA-B complexes can
be found at the plasma membrane, while most HLA-C and HLA-F molecules
reside in the endoplasmic reticulum and Golgi membrane, and HLA-A
molecules are more equally distributed over these cellular compartments.
This allotype-specific cellular distribution of HLA molecules should
be taken into account when analyzing peptide antigen presentation
by immunopeptidomics.
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Affiliation(s)
- Max Hoek
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Laura C Demmers
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Wei Wu
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, Utrecht 3584 CH, The Netherlands
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12
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Joyce S, Ternette N. Know thy immune self and non-self: Proteomics informs on the expanse of self and non-self, and how and where they arise. Proteomics 2021; 21:e2000143. [PMID: 34310018 PMCID: PMC8865197 DOI: 10.1002/pmic.202000143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/30/2021] [Accepted: 07/19/2021] [Indexed: 12/30/2022]
Abstract
T cells play an important role in the adaptive immune response to a variety of infections and cancers. Initiation of a T cell mediated immune response requires antigen recognition in a process termed MHC (major histocompatibility complex) restri ction. A T cell antigen is a composite structure made up of a peptide fragment bound within the antigen‐binding groove of an MHC‐encoded class I or class II molecule. Insight into the precise composition and biology of self and non‐self immunopeptidomes is essential to harness T cell mediated immunity to prevent, treat, or cure infectious diseases and cancers. T cell antigen discovery is an arduous task! The pioneering work in the early 1990s has made large‐scale T cell antigen discovery possible. Thus, advancements in mass spectrometry coupled with proteomics and genomics technologies make possible T cell antigen discovery with ease, accuracy, and sensitivity. Yet we have only begun to understand the breadth and the depth of self and non‐self immunopeptidomes because the molecular biology of the cell continues to surprise us with new secrets directly related to the source, and the processing and presentation of MHC ligands. Focused on MHC class I molecules, this review, therefore, provides a brief historic account of T cell antigen discovery and, against a backdrop of key advances in molecular cell biologic processes, elaborates on how proteogenomics approaches have revolutionised the field.
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Affiliation(s)
- Sebastian Joyce
- Department of Veterans Affairs, Tennessee Valley Healthcare System and the Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Nicola Ternette
- Centre for Cellular and Molecular Physiology, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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13
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Shide K. Calreticulin mutations in myeloproliferative neoplasms. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 365:179-226. [PMID: 34756244 DOI: 10.1016/bs.ircmb.2021.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Calreticulin (CALR) is a chaperone present in the endoplasmic reticulum, which is involved in the quality control of N-glycosylated proteins and storage of calcium ions. In 2013, the C-terminal mutation in CALR was identified in half of the patients with essential thrombocythemia and primary myelofibrosis who did not have a JAK2 or MPL mutation. The results of 8 years of intensive research are changing the clinical practice associated with treating myeloproliferative neoplasms (MPNs). The presence or absence of CALR mutations and their mutation types already provide important information for diagnosis and treatment decision making. In addition, the interaction with the thrombopoietin receptor MPL, which is the main mechanism of transformation by CALR mutation, and the expression of the mutant protein on the cell surface have a great potential as targets for molecular-targeted drugs and immunotherapy. This chapter presents recent findings on the clinical significance of the CALR mutation and the molecular basis by which this mutation drives MPNs.
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Affiliation(s)
- Kotaro Shide
- Division of Haematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
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14
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Aflalo A, Boyle LH. Polymorphisms in MHC class I molecules influence their interactions with components of the antigen processing and presentation pathway. Int J Immunogenet 2021; 48:317-325. [PMID: 34176210 DOI: 10.1111/iji.12546] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/12/2021] [Accepted: 05/24/2021] [Indexed: 10/21/2022]
Abstract
MHC class I (MHC-I) molecules undergo an intricate folding process in order to pick up antigenic peptide to present to the immune system. In recent years, the discovery of a new peptide editor for MHC-I has added an extra level of complexity in our understanding of how peptide presentation is regulated. On top of this, the incredible diversity in MHC-I molecules leads to significant variation in the interaction between MHC-I and components of the antigen processing and presentation pathway. Here, we review our current understanding regarding how polymorphisms in human leukocyte antigen class I molecules influence their interactions with key components of the antigen processing and presentation pathway. A deeper understanding of this may offer new insights regarding how apparently subtle variation in MHC-I can have a significant impact on susceptibility to disease.
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Affiliation(s)
- Aure Aflalo
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Cambridge, UK
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15
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Jongsma MLM, Neefjes J, Spaapen RM. Playing hide and seek: Tumor cells in control of MHC class I antigen presentation. Mol Immunol 2021; 136:36-44. [PMID: 34082257 DOI: 10.1016/j.molimm.2021.05.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/07/2021] [Accepted: 05/18/2021] [Indexed: 12/15/2022]
Abstract
MHC class I (MHC-I) molecules present a blueprint of the intracellular proteome to T cells allowing them to control infection or malignant transformation. As a response, pathogens and tumor cells often downmodulate MHC-I mediated antigen presentation to escape from immune surveillance. Although the fundamental rules of antigen presentation are known in detail, the players in this system are not saturated and new modules of regulation have recently been uncovered. Here, we update the understanding of antigen presentation by MHC-I molecules and how this can be exploited by tumors to prevent exposure of the intracellular proteome. This knowledge can provide new ways to improve immune responses against tumors and pathogens.
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Affiliation(s)
- M L M Jongsma
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Center, Leiden, the Netherlands
| | - J Neefjes
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Center, Leiden, the Netherlands
| | - R M Spaapen
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands.
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16
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Halabi S, Ghosh M, Stevanović S, Rammensee HG, Bertzbach LD, Kaufer BB, Moncrieffe MC, Kaspers B, Härtle S, Kaufman J. The dominantly expressed class II molecule from a resistant MHC haplotype presents only a few Marek's disease virus peptides by using an unprecedented binding motif. PLoS Biol 2021; 19:e3001057. [PMID: 33901176 PMCID: PMC8101999 DOI: 10.1371/journal.pbio.3001057] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 05/06/2021] [Accepted: 03/31/2021] [Indexed: 12/14/2022] Open
Abstract
Viral diseases pose major threats to humans and other animals, including the billions of chickens that are an important food source as well as a public health concern due to zoonotic pathogens. Unlike humans and other typical mammals, the major histocompatibility complex (MHC) of chickens can confer decisive resistance or susceptibility to many viral diseases. An iconic example is Marek's disease, caused by an oncogenic herpesvirus with over 100 genes. Classical MHC class I and class II molecules present antigenic peptides to T lymphocytes, and it has been hard to understand how such MHC molecules could be involved in susceptibility to Marek's disease, given the potential number of peptides from over 100 genes. We used a new in vitro infection system and immunopeptidomics to determine peptide motifs for the 2 class II molecules expressed by the MHC haplotype B2, which is known to confer resistance to Marek's disease. Surprisingly, we found that the vast majority of viral peptide epitopes presented by chicken class II molecules arise from only 4 viral genes, nearly all having the peptide motif for BL2*02, the dominantly expressed class II molecule in chickens. We expressed BL2*02 linked to several Marek's disease virus (MDV) peptides and determined one X-ray crystal structure, showing how a single small amino acid in the binding site causes a crinkle in the peptide, leading to a core binding peptide of 10 amino acids, compared to the 9 amino acids in all other reported class II molecules. The limited number of potential T cell epitopes from such a complex virus can explain the differential MHC-determined resistance to MDV, but raises questions of mechanism and opportunities for vaccine targets in this important food species, as well as providing a basis for understanding class II molecules in other species including humans.
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Affiliation(s)
- Samer Halabi
- University of Cambridge, Department of Pathology, Cambridge, United Kingdom
- University of Edinburgh, Institute for Immunology and Infection Research, Edinburgh, United Kingdom
| | - Michael Ghosh
- University of Tübingen, Department of Immunology, Institute of Cell Biology, Tübingen, Germany
| | - Stefan Stevanović
- University of Tübingen, Department of Immunology, Institute of Cell Biology, Tübingen, Germany
| | - Hans-Georg Rammensee
- University of Tübingen, Department of Immunology, Institute of Cell Biology, Tübingen, Germany
| | | | | | | | - Bernd Kaspers
- Ludwig Maximillians University, Veterinary Faculty, Planegg, Germany
| | - Sonja Härtle
- Ludwig Maximillians University, Veterinary Faculty, Planegg, Germany
| | - Jim Kaufman
- University of Cambridge, Department of Pathology, Cambridge, United Kingdom
- University of Edinburgh, Institute for Immunology and Infection Research, Edinburgh, United Kingdom
- University of Cambridge, Department of Veterinary Medicine, Cambridge, United Kingdom
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17
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Kielbik M, Szulc-Kielbik I, Klink M. Calreticulin-Multifunctional Chaperone in Immunogenic Cell Death: Potential Significance as a Prognostic Biomarker in Ovarian Cancer Patients. Cells 2021; 10:130. [PMID: 33440842 PMCID: PMC7827772 DOI: 10.3390/cells10010130] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 12/11/2022] Open
Abstract
Immunogenic cell death (ICD) is a type of death, which has the hallmarks of necroptosis and apoptosis, and is best characterized in malignant diseases. Chemotherapeutics, radiotherapy and photodynamic therapy induce intracellular stress response pathways in tumor cells, leading to a secretion of various factors belonging to a family of damage-associated molecular patterns molecules, capable of inducing the adaptive immune response. One of them is calreticulin (CRT), an endoplasmic reticulum-associated chaperone. Its presence on the surface of dying tumor cells serves as an "eat me" signal for antigen presenting cells (APC). Engulfment of tumor cells by APCs results in the presentation of tumor's antigens to cytotoxic T-cells and production of cytokines/chemokines, which activate immune cells responsible for tumor cells killing. Thus, the development of ICD and the expression of CRT can help standard therapy to eradicate tumor cells. Here, we review the physiological functions of CRT and its involvement in the ICD appearance in malignant disease. Moreover, we also focus on the ability of various anti-cancer drugs to induce expression of surface CRT on ovarian cancer cells. The second aim of this work is to discuss and summarize the prognostic/predictive value of CRT in ovarian cancer patients.
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Affiliation(s)
- Michal Kielbik
- Institute of Medical Biology, Polish Academy of Sciences, 106 Lodowa Str., 93-232 Lodz, Poland; (I.S.-K.); (M.K.)
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18
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Roles of Calreticulin in Protein Folding, Immunity, Calcium Signaling and Cell Transformation. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 59:145-162. [PMID: 34050865 DOI: 10.1007/978-3-030-67696-4_7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The endoplasmic reticulum (ER) is an organelle that mediates the proper folding and assembly of proteins destined for the cell surface, the extracellular space and subcellular compartments such as the lysosomes. The ER contains a wide range of molecular chaperones to handle the folding requirements of a diverse set of proteins that traffic through this compartment. The lectin-like chaperones calreticulin and calnexin are an important class of structurally-related chaperones relevant for the folding and assembly of many N-linked glycoproteins. Despite the conserved mechanism of action of these two chaperones in nascent protein recognition and folding, calreticulin has unique functions in cellular calcium signaling and in the immune response. The ER-related functions of calreticulin in the assembly of major histocompatibility complex (MHC) class I molecules are well-studied and provide many insights into the modes of substrate and co-chaperone recognition by calreticulin. Calreticulin is also detectable on the cell surface under some conditions, where it induces the phagocytosis of apoptotic cells. Furthermore, mutations of calreticulin induce cell transformation in myeloproliferative neoplasms (MPN). Studies of the functions of the mutant calreticulin in cell transformation and immunity have provided many insights into the normal biology of calreticulin, which are discussed.
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19
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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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20
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Abstract
Calreticulin (CALR) is an endoplasmic reticulum (ER)-resident protein involved in a spectrum of cellular processes. In healthy cells, CALR operates as a chaperone and Ca2+ buffer to assist correct protein folding within the ER. Besides favoring the maintenance of cellular proteostasis, these cell-intrinsic CALR functions support Ca2+-dependent processes, such as adhesion and integrin signaling, and ensure normal antigen presentation on MHC Class I molecules. Moreover, cancer cells succumbing to immunogenic cell death (ICD) expose CALR on their surface, which promotes the uptake of cell corpses by professional phagocytes and ultimately supports the initiation of anticancer immunity. Thus, loss-of-function CALR mutations promote oncogenesis not only as they impair cellular homeostasis in healthy cells, but also as they compromise natural and therapy-driven immunosurveillance. However, the prognostic impact of total or membrane-exposed CALR levels appears to vary considerably with cancer type. For instance, while genetic CALR defects promote pre-neoplastic myeloproliferation, patients with myeloproliferative neoplasms bearing CALR mutations often experience improved overall survival as compared to patients bearing wild-type CALR. Here, we discuss the context-dependent impact of CALR on malignant transformation, tumor progression and response to cancer therapy.
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21
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Margulies DH, Jiang J, Natarajan K. Structural and dynamic studies of TAPBPR and Tapasin reveal the mechanism of peptide loading of MHC-I molecules. Curr Opin Immunol 2020; 64:71-79. [DOI: 10.1016/j.coi.2020.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/24/2020] [Accepted: 04/03/2020] [Indexed: 12/17/2022]
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22
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De Bousser E, Meuris L, Callewaert N, Festjens N. Human T cell glycosylation and implications on immune therapy for cancer. Hum Vaccin Immunother 2020; 16:2374-2388. [PMID: 32186959 PMCID: PMC7644206 DOI: 10.1080/21645515.2020.1730658] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Glycosylation is an important post-translational modification, giving rise to a diverse and abundant repertoire of glycans on the cell surface, collectively known as the glycome. When focusing on immunity, glycans are indispensable in virtually all signaling and cell-cell interactions. More specifically, glycans have been shown to regulate key pathophysiological steps within T cell biology such as T cell development, thymocyte selection, T cell activity and signaling as well as T cell differentiation and proliferation. They are of major importance in determining the interaction of human T cells with tumor cells. In this review, we will describe the role of glycosylation of human T cells in more depth, elaborate on the importance of glycosylation in the interaction of human T cells with tumor cells and discuss the potential of cancer immunotherapies that are based on manipulating the glycome functions at the tumor immune interface.1,2
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Affiliation(s)
- Elien De Bousser
- VIB-UGent Center for Medical Biotechnology , Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University , Ghent, Belgium
| | - Leander Meuris
- VIB-UGent Center for Medical Biotechnology , Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University , Ghent, Belgium
| | - Nico Callewaert
- VIB-UGent Center for Medical Biotechnology , Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University , Ghent, Belgium
| | - Nele Festjens
- VIB-UGent Center for Medical Biotechnology , Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University , Ghent, Belgium
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23
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Sagert L, Hennig F, Thomas C, Tampé R. A loop structure allows TAPBPR to exert its dual function as MHC I chaperone and peptide editor. eLife 2020; 9:55326. [PMID: 32167472 PMCID: PMC7117912 DOI: 10.7554/elife.55326] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/12/2020] [Indexed: 01/18/2023] Open
Abstract
Adaptive immunity vitally depends on major histocompatibility complex class I (MHC I) molecules loaded with peptides. Selective loading of peptides onto MHC I, referred to as peptide editing, is catalyzed by tapasin and the tapasin-related TAPBPR. An important catalytic role has been ascribed to a structural feature in TAPBPR called the scoop loop, but the exact function of the scoop loop remains elusive. Here, using a reconstituted system of defined peptide-exchange components including human TAPBPR variants, we uncover a substantial contribution of the scoop loop to the stability of the MHC I-chaperone complex and to peptide editing. We reveal that the scoop loop of TAPBPR functions as an internal peptide surrogate in peptide-depleted environments stabilizing empty MHC I and impeding peptide rebinding. The scoop loop thereby acts as an additional selectivity filter in shaping the repertoire of presented peptide epitopes and the formation of a hierarchical immune response.
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Affiliation(s)
- Lina Sagert
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany
| | - Felix Hennig
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany
| | - Christoph Thomas
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany
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24
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de Haas P, Hendriks WJAJ, Lefeber DJ, Cambi A. Biological and Technical Challenges in Unraveling the Role of N-Glycans in Immune Receptor Regulation. Front Chem 2020; 8:55. [PMID: 32117881 PMCID: PMC7013033 DOI: 10.3389/fchem.2020.00055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/17/2020] [Indexed: 12/15/2022] Open
Abstract
N-glycosylation of membrane receptors is important for a wide variety of cellular processes. In the immune system, loss or alteration of receptor glycosylation can affect pathogen recognition, cell-cell interaction, and activation as well as migration. This is not only due to aberrant folding of the receptor, but also to altered lateral mobility or aggregation capacity. Despite increasing evidence of their biological relevance, glycosylation-dependent mechanisms of receptor regulation are hard to dissect at the molecular level. This is due to the intrinsic complexity of the glycosylation process and high diversity of glycan structures combined with the technical limitations of the current experimental tools. It is still challenging to precisely determine the localization and site-occupancy of glycosylation sites, glycan micro- and macro-heterogeneity at the individual receptor level as well as the biological function and specific interactome of receptor glycoforms. In addition, the tools available to manipulate N-glycans of a specific receptor are limited. Significant progress has however been made thanks to innovative approaches such as glycoproteomics, metabolic engineering, or chemoenzymatic labeling. By discussing examples of immune receptors involved in pathogen recognition, migration, antigen presentation, and cell signaling, this Mini Review will focus on the biological importance of N-glycosylation for receptor functions and highlight the technical challenges for examination and manipulation of receptor N-glycans.
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Affiliation(s)
- Paola de Haas
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Wiljan J A J Hendriks
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Dirk J Lefeber
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Alessandra Cambi
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
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25
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Trowitzsch S, Tampé R. Multifunctional Chaperone and Quality Control Complexes in Adaptive Immunity. Annu Rev Biophys 2020; 49:135-161. [PMID: 32004089 DOI: 10.1146/annurev-biophys-121219-081643] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The fundamental process of adaptive immunity relies on the differentiation of self from nonself. Nucleated cells are continuously monitored by effector cells of the immune system, which police the peptide status presented via cell surface molecules. Recent integrative structural approaches have provided insights toward our understanding of how sophisticated cellular machineries shape such hierarchical immune surveillance. Biophysical and structural achievements were invaluable for defining the interconnection of many key factors during antigen processing and presentation, and helped to solve several conundrums that persisted for many years. In this review, we illuminate the numerous quality control machineries involved in different steps during the maturation of major histocompatibility complex class I (MHC I) proteins, from their synthesis in the endoplasmic reticulum to folding and trafficking via the secretory pathway, optimization of antigenic cargo, final release to the cell surface, and engagement with their cognate receptors on cytotoxic T lymphocytes.
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Affiliation(s)
- Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; ,
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; ,
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26
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O’Rourke SM, Morozov GI, Roberts JT, Barb AW, Sgourakis NG. Production of soluble pMHC-I molecules in mammalian cells using the molecular chaperone TAPBPR. Protein Eng Des Sel 2019; 32:525-532. [PMID: 32725167 PMCID: PMC7451022 DOI: 10.1093/protein/gzaa015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/23/2020] [Accepted: 06/29/2020] [Indexed: 12/20/2022] Open
Abstract
Current approaches for generating major histocompatibility complex (MHC) Class-I proteins with desired bound peptides (pMHC-I) for research, diagnostic and therapeutic applications are limited by the inherent instability of empty MHC-I molecules. Using the properties of the chaperone TAP-binding protein related (TAPBPR), we have developed a robust method to produce soluble, peptide-receptive MHC-I molecules in Chinese Hamster Ovary cells at high yield, completely bypassing the requirement for laborious refolding from inclusion bodies expressed in E.coli. Purified MHC-I/TAPBPR complexes can be prepared for multiple human allotypes, and exhibit complex glycan modifications at the conserved Asn 86 residue. As a proof of concept, we demonstrate both HLA allele-specific peptide binding and MHC-restricted antigen recognition by T cells for two relevant tumor-associated antigens. Our system provides a facile, high-throughput approach for generating pMHC-I antigens to probe and expand TCR specificities present in polyclonal T cell repertoires.
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Affiliation(s)
- Sara M O’Rourke
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Giora I Morozov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jacob T Roberts
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Adam W Barb
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center University of Georgia, Athens, GA 30602, USA
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA
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27
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Praest P, Liaci AM, Förster F, Wiertz EJ. New insights into the structure of the MHC class I peptide-loading complex and mechanisms of TAP inhibition by viral immune evasion proteins. Mol Immunol 2019; 113:103-114. [DOI: 10.1016/j.molimm.2018.03.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/16/2018] [Accepted: 03/22/2018] [Indexed: 01/08/2023]
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28
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De novo glycan structural identification from mass spectra using tree merging strategy. Comput Biol Chem 2019; 80:217-224. [DOI: 10.1016/j.compbiolchem.2019.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 03/23/2019] [Indexed: 11/19/2022]
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29
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Thomas C, Tampé R. MHC I chaperone complexes shaping immunity. Curr Opin Immunol 2019; 58:9-15. [DOI: 10.1016/j.coi.2019.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/16/2018] [Accepted: 01/04/2019] [Indexed: 01/21/2023]
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30
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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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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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Mouse Norovirus Infection Reduces the Surface Expression of Major Histocompatibility Complex Class I Proteins and Inhibits CD8 + T Cell Recognition and Activation. J Virol 2018; 92:JVI.00286-18. [PMID: 29976673 DOI: 10.1128/jvi.00286-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/28/2018] [Indexed: 12/12/2022] Open
Abstract
Human noroviruses are highly infectious single-stranded RNA (ssRNA) viruses and the major cause of nonbacterial gastroenteritis worldwide. With the discovery of murine norovirus (MNV) and the introduction of an effective model for norovirus infection and replication, knowledge about infection mechanisms and their impact on the host immune response has progressed. A major player in the immune response against viral infections is the group of major histocompatibility complex (MHC) class I proteins, which present viral antigen to immune cells. We have observed that MNV interferes with the antigen presentation pathway in infected cells by reducing the surface expression of MHC class I proteins. We have shown that MNV-infected dendritic cells or macrophages have lower levels of surface expression of MHC class I proteins than uninfected and bystander cells. Transcriptional analysis revealed that this defect is not due to a decreased amount of mRNA but is reflected at the protein level. We have determined that this defect is mediated via the MNV NS3 protein. Significantly, treatment of MNV-infected cells with the endocytic recycling inhibitor dynasore completely restored the surface expression of MHC class I proteins, whereas treatment with the proteasome inhibitor MG132 partly restored such expression. These observations indicate a role for endocytic recycling and proteasome-mediated degradation of these proteins. Importantly, we show that due to the reduced surface expression of MHC class I proteins, antigen presentation is inhibited, resulting in the inability of CD8+ T cells to become activated in the presence of MNV-infected cells.IMPORTANCE Human noroviruses (HuNoVs) are the major cause of nonbacterial gastroenteritis worldwide and impose a great burden on patients and health systems every year. So far, no antiviral treatment or vaccine is available. We show that MNV evades the host immune response by reducing the amount of MHC class I proteins displayed on the cell surface. This reduction leads to a decrease in viral antigen presentation and interferes with the CD8+ T cell response. CD8+ T cells respond to foreign antigen by activating cytotoxic pathways and inducing immune memory to the infection. By evading this immune response, MNV is able to replicate efficiently in the host, and the ability of cells to respond to consecutive infections is impaired. These findings have a major impact on our understanding of the ways in which noroviruses interact with the host immune response and manipulate immune memory.
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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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Natarajan K, Jiang J, May NA, Mage MG, Boyd LF, McShan AC, Sgourakis NG, Bax A, Margulies DH. The Role of Molecular Flexibility in Antigen Presentation and T Cell Receptor-Mediated Signaling. Front Immunol 2018; 9:1657. [PMID: 30065727 PMCID: PMC6056622 DOI: 10.3389/fimmu.2018.01657] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/04/2018] [Indexed: 01/20/2023] Open
Abstract
Antigen presentation is a cellular process that involves a number of steps, beginning with the production of peptides by proteolysis or aberrant synthesis and the delivery of peptides to cellular compartments where they are loaded on MHC class I (MHC-I) or MHC class II (MHC-II) molecules. The selective loading and editing of high-affinity immunodominant antigens is orchestrated by molecular chaperones: tapasin/TAP-binding protein, related for MHC-I and HLA-DM for MHC-II. Once peptide/MHC (pMHC) complexes are assembled, following various steps of quality control, they are delivered to the cell surface, where they are available for identification by αβ receptors on CD8+ or CD4+ T lymphocytes. In addition, recognition of cell surface peptide/MHC-I complexes by natural killer cell receptors plays a regulatory role in some aspects of the innate immune response. Many of the components of the pathways of antigen processing and presentation and of T cell receptor (TCR)-mediated signaling have been studied extensively by biochemical, genetic, immunological, and structural approaches over the past several decades. Until recently, however, dynamic aspects of the interactions of peptide with MHC, MHC with molecular chaperones, or of pMHC with TCR have been difficult to address experimentally, although computational approaches such as molecular dynamics (MD) simulations have been illuminating. Studies exploiting X-ray crystallography, cryo-electron microscopy, and multidimensional nuclear magnetic resonance (NMR) spectroscopy are beginning to reveal the importance of molecular flexibility as it pertains to peptide loading onto MHC molecules, the interactions between pMHC and TCR, and subsequent TCR-mediated signals. In addition, recent structural and dynamic insights into how molecular chaperones define peptide selection and fine-tune the MHC displayed antigen repertoire are discussed. Here, we offer a review of current knowledge that highlights experimental data obtained by X-ray crystallography and multidimensional NMR methodologies. Collectively, these findings strongly support a multifaceted role for protein plasticity and conformational dynamics throughout the antigen processing and presentation pathway in dictating antigen selection and recognition.
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Affiliation(s)
- Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Nathan A May
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Michael G Mage
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Lisa F Boyd
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Andrew C McShan
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
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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: 55] [Impact Index Per Article: 9.2] [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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Dijkstra JM, Yamaguchi T, Grimholt U. Conservation of sequence motifs suggests that the nonclassical MHC class I lineages CD1/PROCR and UT were established before the emergence of tetrapod species. Immunogenetics 2017; 70:459-476. [DOI: 10.1007/s00251-017-1050-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 12/05/2017] [Indexed: 01/09/2023]
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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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Structure of the human MHC-I peptide-loading complex. Nature 2017; 551:525-528. [PMID: 29107940 DOI: 10.1038/nature24627] [Citation(s) in RCA: 253] [Impact Index Per Article: 36.1] [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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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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41
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Calles-Garcia D, Yang M, Soya N, Melero R, Ménade M, Ito Y, Vargas J, Lukacs GL, Kollman JM, Kozlov G, Gehring K. Single-particle electron microscopy structure of UDP-glucose:glycoprotein glucosyltransferase suggests a selectivity mechanism for misfolded proteins. J Biol Chem 2017; 292:11499-11507. [PMID: 28490633 DOI: 10.1074/jbc.m117.789495] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/07/2017] [Indexed: 11/06/2022] Open
Abstract
The enzyme UDP-glucose:glycoprotein glucosyltransferase (UGGT) mediates quality control of glycoproteins in the endoplasmic reticulum by attaching glucose to N-linked glycan of misfolded proteins. As a sensor, UGGT ensures that misfolded proteins are recognized by the lectin chaperones and do not leave the secretory pathway. The structure of UGGT and the mechanism of its selectivity for misfolded proteins have been unknown for 25 years. Here, we used negative-stain electron microscopy and small-angle X-ray scattering to determine the structure of UGGT from Drosophila melanogaster at 18-Å resolution. Three-dimensional reconstructions revealed a cage-like structure with a large central cavity. Particle classification revealed flexibility that precluded determination of a high-resolution structure. Introduction of biotinylation sites into a fungal UGGT expressed in Escherichia coli allowed identification of the catalytic and first thioredoxin-like domains. We also used hydrogen-deuterium exchange mass spectrometry to map the binding site of an accessory protein, Sep15, to the first thioredoxin-like domain. The UGGT structural features identified suggest that the central cavity contains the catalytic site and is lined with hydrophobic surfaces. This enhances the binding of misfolded substrates with exposed hydrophobic residues and excludes folded proteins with hydrophilic surfaces. In conclusion, we have determined the UGGT structure, which enabled us to develop a plausible functional model of the mechanism for UGGT's selectivity for misfolded glycoproteins.
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Affiliation(s)
- Daniel Calles-Garcia
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Meng Yang
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Naoto Soya
- Department of Physiology, McGill University, Montreal, Quebec H3G1Y6, Canada
| | - Roberto Melero
- Biocomputing Unit, Centro Nacional de Biotectnologíay, 28049 Madrid, Spain
| | - Marie Ménade
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Yukishige Ito
- Synthetic Cellular Chemistry Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Javier Vargas
- Biocomputing Unit, Centro Nacional de Biotectnologíay, 28049 Madrid, Spain.,Bioengineering Lab, Escuela Politécnica Superior, Universidad San Pablo CEU, 28668 Madrid, Spain, and
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Montreal, Quebec H3G1Y6, Canada
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350
| | - Guennadi Kozlov
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Kalle Gehring
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada,
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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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Lum R, Ahmad S, Hong SJ, Chapman DC, Kozlov G, Williams DB. Contributions of the Lectin and Polypeptide Binding Sites of Calreticulin to Its Chaperone Functions in Vitro and in Cells. J Biol Chem 2016; 291:19631-41. [PMID: 27413183 DOI: 10.1074/jbc.m116.746321] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 11/06/2022] Open
Abstract
Calreticulin is a lectin chaperone of the endoplasmic reticulum that interacts with newly synthesized glycoproteins by binding to Glc1Man9GlcNAc2 oligosaccharides as well as to the polypeptide chain. In vitro, the latter interaction potently suppresses the aggregation of various non-glycosylated proteins. Although the lectin-oligosaccharide association is well understood, the polypeptide-based interaction is more controversial because the binding site on calreticulin has not been identified, and its significance in the biogenesis of glycoproteins in cells remains unknown. In this study, we identified the polypeptide binding site responsible for the in vitro aggregation suppression function by mutating four candidate hydrophobic surface patches. Mutations in only one patch, P19K/I21E and Y22K/F84E, impaired the ability of calreticulin to suppress the thermally induced aggregation of non-glycosylated firefly luciferase. These mutants also failed to bind several hydrophobic peptides that act as substrate mimetics and compete in the luciferase aggregation suppression assay. To assess the relative contributions of the glycan-dependent and -independent interactions in living cells, we expressed lectin-deficient, polypeptide binding-deficient, and doubly deficient calreticulin constructs in calreticulin-negative cells and monitored the effects on the biogenesis of MHC class I molecules, the solubility of mutant forms of α1-antitrypsin, and interactions with newly synthesized glycoproteins. In all cases, we observed a profound impairment in calreticulin function when its lectin site was inactivated. Remarkably, inactivation of the polypeptide binding site had little impact. These findings indicate that the lectin-based mode of client interaction is the predominant contributor to the chaperone functions of calreticulin within the endoplasmic reticulum.
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Affiliation(s)
- Ronnie Lum
- From the Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Samar Ahmad
- From the Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Seo Jung Hong
- From the Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Daniel C Chapman
- From the Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Guennadi Kozlov
- the Groupe de Recherche Axé sur la Structure des Proteines, Department of Biochemistry, McGill University, Montréal, Québec H3G 0B1, Canada
| | - David B Williams
- From the Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
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Zhang P, Woen S, Wang T, Liau B, Zhao S, Chen C, Yang Y, Song Z, Wormald MR, Yu C, Rudd PM. Challenges of glycosylation analysis and control: an integrated approach to producing optimal and consistent therapeutic drugs. Drug Discov Today 2016; 21:740-65. [DOI: 10.1016/j.drudis.2016.01.006] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/22/2015] [Accepted: 01/14/2016] [Indexed: 12/18/2022]
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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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Regulation of calreticulin-major histocompatibility complex (MHC) class I interactions by ATP. Proc Natl Acad Sci U S A 2015; 112:E5608-17. [PMID: 26420867 DOI: 10.1073/pnas.1510132112] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The MHC class I peptide loading complex (PLC) facilitates the assembly of MHC class I molecules with peptides, but factors that regulate the stability and dynamics of the assembly complex are largely uncharacterized. Based on initial findings that ATP, in addition to MHC class I-specific peptide, is able to induce MHC class I dissociation from the PLC, we investigated the interaction of ATP with the chaperone calreticulin, an endoplasmic reticulum (ER) luminal, calcium-binding component of the PLC that is known to bind ATP. We combined computational and experimental measurements to identify residues within the globular domain of calreticulin, in proximity to the high-affinity calcium-binding site, that are important for high-affinity ATP binding and for ATPase activity. High-affinity calcium binding by calreticulin is required for optimal nucleotide binding, but both ATP and ADP destabilize enthalpy-driven high-affinity calcium binding to calreticulin. ATP also selectively destabilizes the interaction of calreticulin with cellular substrates, including MHC class I molecules. Calreticulin mutants that affect ATP or high-affinity calcium binding display prolonged associations with monoglucosylated forms of cellular MHC class I, delaying MHC class I dissociation from the PLC and their transit through the secretory pathway. These studies reveal central roles for ATP and calcium binding as regulators of calreticulin-substrate interactions and as key determinants of PLC dynamics.
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48
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Caramelo JJ, Parodi AJ. A sweet code for glycoprotein folding. FEBS Lett 2015; 589:3379-87. [PMID: 26226420 DOI: 10.1016/j.febslet.2015.07.021] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 07/15/2015] [Accepted: 07/15/2015] [Indexed: 12/11/2022]
Abstract
Glycoprotein synthesis is initiated in the endoplasmic reticulum (ER) lumen upon transfer of a glycan (Glc3Man9GlcNAc2) from a lipid derivative to Asn residues (N-glycosylation). N-Glycan-dependent quality control of glycoprotein folding in the ER prevents exit to Golgi of folding intermediates, irreparably misfolded glycoproteins and incompletely assembled multimeric complexes. It also enhances folding efficiency by preventing aggregation and facilitating formation of proper disulfide bonds. The control mechanism essentially involves four components, resident lectin-chaperones (calnexin and calreticulin) that recognize monoglucosylated polymannose protein-linked glycans, lectin-associated oxidoreductase acting on monoglucosylated glycoproteins (ERp57), a glucosyltransferase that creates monoglucosylated epitopes in protein-linked glycans (UGGT) and a glucosidase (GII) that removes the glucose units added by UGGT. This last enzyme is the only mechanism component sensing glycoprotein conformations as it creates monoglucosylated glycans exclusively in not properly folded glycoproteins or in not completely assembled multimeric glycoprotein complexes. Glycoproteins that fail to properly fold are eventually driven to proteasomal degradation in the cytosol following the ER-associated degradation pathway, in which the extent of N-glycan demannosylation by ER mannosidases play a relevant role in the identification of irreparably misfolded glycoproteins.
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Affiliation(s)
- Julio J Caramelo
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Avda. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina.
| | - Armando J Parodi
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Avda. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina.
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Transport and quality control of MHC class I molecules in the early secretory pathway. Curr Opin Immunol 2015; 34:83-90. [PMID: 25771183 DOI: 10.1016/j.coi.2015.02.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 02/21/2015] [Accepted: 02/24/2015] [Indexed: 12/26/2022]
Abstract
Folding and peptide binding of major histocompatibility complex (MHC) class I molecules have been thoroughly researched, but the mechanistic connection between these biochemical events and the progress of class I through the early secretory pathway is much less well understood. This review focuses on the question how the partially assembled forms of class I (which lack high-affinity peptide and/or the light chain beta-2 microglobulin) are retained inside the cell. Such investigations offer researchers exciting chances to understand the connections between class I structure, conformational dynamics, peptide binding kinetics and thermodynamics, intracellular transport, and antigen presentation.
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50
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Rizvi SM, Salam N, Geng J, Qi Y, Bream JH, Duggal P, Hussain SK, Martinson J, Wolinsky SM, Carrington M, Raghavan M. Distinct assembly profiles of HLA-B molecules. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 192:4967-76. [PMID: 24790147 PMCID: PMC4117407 DOI: 10.4049/jimmunol.1301670] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
MHC class I polymorphisms are known to influence outcomes in a number of infectious diseases, cancers, and inflammatory diseases. Human MHC class I H chains are encoded by the HLA-A, HLA-B, and HLA-C genes. These genes are highly polymorphic, with the HLA-B locus being the most variable. Each HLA class I protein binds to a distinct set of peptide Ags, which are presented to CD8(+) T cells. HLA-disease associations have been shown in some cases to link to the peptide-binding characteristics of individual HLA class I molecules. In this study, we show that polymorphisms at the HLA-B locus profoundly influence the assembly characteristics of HLA-B molecules and the stabilities of their peptide-deficient forms. In particular, dependence on the assembly factor tapasin is highly variable, with frequent occurrence of strongly tapasin-dependent or independent allotypes. Several polymorphic HLA-B residues located near the C-terminal end of the peptide are key determinants of tapasin-independent assembly. In vitro refolded forms of tapasin-independent allotypes assemble more readily with peptides compared to tapasin-dependent allotypes that belong to the same supertype, and, during refolding, reduced aggregation of tapasin-independent allotypes is observed. Paradoxically, in HIV-infected individuals, greater tapasin-independent HLA-B assembly confers more rapid progression to death, consistent with previous findings that some HLA-B allotypes shown to be tapasin independent are associated with rapid progression to multiple AIDS outcomes. Together, these findings demonstrate significant variations in the assembly of HLA-B molecules and indicate influences of HLA-B-folding patterns upon infectious disease outcomes.
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Affiliation(s)
- Syed Monem Rizvi
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Nasir Salam
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Jie Geng
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Ying Qi
- Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21702; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139
| | - Jay H Bream
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Priya Duggal
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Shehnaz K Hussain
- Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA 90095; Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048
| | - Jeremy Martinson
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Steven M Wolinsky
- Division of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Mary Carrington
- Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21702; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139
| | - Malini Raghavan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109;
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