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Abstract
Major histocompatibility complex (MHC) class I molecules function to present pathogen derived peptides to cytotoxic T cells and act as ligands for Natural Killer cells, thus alerting the immune system to the presence of invading pathogens. However, some MHC class I molecules, most notably HLA-B27, can be strongly associated with autoimmune diseases. In addition, the MHC class I pathway is a target for numerous viral evasion strategies Understanding not only the antigen presenting functions, but also the biosynthesis and the degradation pathways of MHC class I molecules has therefore become important in determining their role in pathogen and autoimmune related diseases. Here, we describe how using epitope tagged MHC class I molecules can aid in the analysis of MHC class I molecule biosynthesis and degradation as well as complementary studies using conventional conformationally specific antibodies. Coupled together with pharmacological manipulation which can target both biosynthetic and degradative pathways, this offers a powerful tool in analyzing MHC class I molecules.
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van Hateren A, Bailey A, Werner JM, Elliott T. Plasticity of empty major histocompatibility complex class I molecules determines peptide-selector function. Mol Immunol 2015; 68:98-101. [PMID: 25818313 PMCID: PMC4726658 DOI: 10.1016/j.molimm.2015.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/04/2015] [Accepted: 03/09/2015] [Indexed: 11/28/2022]
Abstract
Major histocompatibility complex class I (MHC I) proteins provide protection from intracellular pathogens and cancer via each of a cell's MHC I molecules binding and presenting a peptide to cytotoxic T lymphocytes. MHC I genes are highly polymorphic and can have significant diversity, with polymorphisms predominantly localised in the peptide-binding groove where they can change peptide-binding specificity. However, polymorphic residues may also determine other functional properties, such as how dependent MHC I alleles are on the peptide-loading complex for optimal acquisition of peptide cargo. We describe how differences in the peptide-binding properties of two MHC I alleles correlates with altered conformational flexibility in the peptide-empty state. We hypothesise that plasticity is an intrinsic property encoded by the protein sequence, and that co-ordinated movements of the membrane-proximal and membrane-distal domains collectively determines how dependent MHC I are on the peptide-loading complex for efficient assembly with high affinity peptides.
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Affiliation(s)
- Andy van Hateren
- Institute for Life Sciences, Building 85, M55, University of Southampton, SO17 1BJ, UK; Cancer Sciences Unit, Faculty of Medicine, University of Southampton, SO16 6YD, UK.
| | - Alistair Bailey
- Institute for Life Sciences, Building 85, M55, University of Southampton, SO17 1BJ, UK; Cancer Sciences Unit, Faculty of Medicine, University of Southampton, SO16 6YD, UK; Centre for Biological Sciences, Faculty of Natural & Environmental Sciences, Building 85, M55, University of Southampton, SO17 1BJ, UK.
| | - Jörn M Werner
- Institute for Life Sciences, Building 85, M55, University of Southampton, SO17 1BJ, UK; Centre for Biological Sciences, Faculty of Natural & Environmental Sciences, Building 85, M55, University of Southampton, SO17 1BJ, UK.
| | - Tim Elliott
- Institute for Life Sciences, Building 85, M55, University of Southampton, SO17 1BJ, UK; Cancer Sciences Unit, Faculty of Medicine, University of Southampton, SO16 6YD, UK.
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Abualrous ET, Fritzsche S, Hein Z, Al-Balushi MS, Reinink P, Boyle LH, Wellbrock U, Antoniou AN, Springer S. F pocket flexibility influences the tapasin dependence of two differentially disease-associated MHC Class I proteins. Eur J Immunol 2015; 45:1248-57. [PMID: 25615938 DOI: 10.1002/eji.201445307] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 12/06/2014] [Accepted: 01/19/2015] [Indexed: 01/01/2023]
Abstract
The human MHC class I protein HLA-B*27:05 is statistically associated with ankylosing spondylitis, unlike HLA-B*27:09, which differs in a single amino acid in the F pocket of the peptide-binding groove. To understand how this unique amino acid difference leads to a different behavior of the proteins in the cell, we have investigated the conformational stability of both proteins using a combination of in silico and experimental approaches. Here, we show that the binding site of B*27:05 is conformationally disordered in the absence of peptide due to a charge repulsion at the bottom of the F pocket. In agreement with this, B*27:05 requires the chaperone protein tapasin to a greater extent than the conformationally stable B*27:09 in order to remain structured and to bind peptide. Taken together, our data demonstrate a method to predict tapasin dependence and physiological behavior from the sequence and crystal structure of a particular class I allotype. Also watch the Video Abstract.
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Affiliation(s)
- Esam T Abualrous
- Department of Life Science and Chemistry, Jacobs University Bremen, Bremen, Germany; Department of Physics, Faculty of Science, Ain Shams University, Cairo, Egypt
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Guiliano DB, Antoniou AN. Measuring synthesis and degradation of MHC class I molecules. Methods Mol Biol 2013; 960:93-108. [PMID: 23329481 DOI: 10.1007/978-1-62703-218-6_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Major histocompatibility complex (MHC) class I molecules function to present pathogen-derived peptides to cytotoxic T cells or act as ligands for Natural Killer cells, thus alerting the immune system to the presence of invading pathogens. Furthermore MHC class I molecules can be strongly associated with autoimmune diseases. Therefore understanding not only the biosynthesis and the degradation pathways of MHC class I molecules has become important in determining their role in pathogen and autoimmune-related diseases. Here we describe how using epitope-tagged MHC class I molecules can aid in the analysis of MHC class I molecule biosynthesis and degradation and also complement studies using conventional conformationally specific antibodies. Coupled together with pharmacological manipulation which can target both biosynthetic and degradative pathways, this offers a powerful tool in analyzing MHC class I molecules.
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Affiliation(s)
- David B Guiliano
- School of Health, Sport and Bioscience, University of East London, London, UK
| | - Antony N Antoniou
- Division of Infection and Immunity/Centre of Rheumatology, Department of Immunology and Molecular Pathology, London, UK.
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Martayan A, Sibilio L, Setini A, Lo Monaco E, Tremante E, Fruci D, Colonna M, Giacomini P. N-linked glycosylation selectively regulates the generic folding of HLA-Cw1. J Biol Chem 2008; 283:16469-76. [PMID: 18420581 DOI: 10.1074/jbc.m709175200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
To resolve primary (glycosylation-assisted) from secondary (glycosylation-independent) quality control steps in the biosynthesis of HLA (human leukocyte antigen) class I glycoproteins, the unique N-linked glycosylation site of the HLA-Cw1 heavy chain was deleted by site-directed mutagenesis. The non-glycosylated Cw1S88G mutant was characterized by flow cytometry, pulse-chase, co-immunoprecipitation, and in vitro assembly assays with synthetic peptide ligands upon transfection in 721.221 and 721.220 cells. The former provide a full set of primary as well as secondary chaperoning interactions, whereas the latter are unable to perform secondary quality control (e.g. proper class I assembly with peptide antigens) as a result of a functional defect of the HLA-dedicated chaperone tapasin. In both transfectants, Cw1S88G displayed a loss/weakening in its generic chaperoning interaction with calreticulin and/or ERp57 and became redistributed toward calnexin, known to bind the most unfolded class I conformers. Despite this, and quite unexpectedly, a weak interaction with the HLA-dedicated chaperone TAP was selectively retained in 721.221. In addition, the ordered, stepwise acquisition of thermal stability/peptide binding was disrupted, resulting in a heterogeneous ensemble of Cw1S88G conformers with unorthodox and unprecedented peptide assembly features. Because a lack of glycosylation and a lack of tapasin-assisted peptide loading have distinct, complementary, and additive effects, the former is separable from (and upstream of) the latter, e.g. primary quality control is suggested to supervise a crucial, generic folding step preliminary to the acquisition of peptide receptivity.
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Affiliation(s)
- Aline Martayan
- Laboratory of Immunology, Regina Elena National Cancer Research Institute, Centro della Ricerca Sperimentale, Via delle Messi d'Oro 156, 00158 Rome, Italy
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Shin J, Park B, Lee S, Kim Y, Biegalke BJ, Kang S, Ahn K. A short isoform of human cytomegalovirus US3 functions as a dominant negative inhibitor of the full-length form. J Virol 2007; 80:5397-404. [PMID: 16699020 PMCID: PMC1472136 DOI: 10.1128/jvi.02397-05] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Human cytomegalovirus encodes four unique short (US) region proteins, each of which is independently sufficient for causing the down-regulation of major histocompatibility complex (MHC) class I molecules on the cell surface. This down-regulation enables infected cells to evade recognition by cytotoxic T lymphocytes (CTLs) but makes them vulnerable to lysis by natural killer (NK) cells, which lyse those cells that lack MHC class I molecules. The 22-kDa US3 glycoprotein is able to down-regulate the surface expression of MHC class I molecules by dual mechanisms: direct endoplasmic reticulum retention by physical association and/or tapasin inhibition. The alternative splicing of the US3 gene generates two additional products, including 17-kDa and 3.5-kDa truncated isoforms; however, the functional significance of these isoforms during viral infection is unknown. Here, we describe a novel mode of self-regulation of US3 function that uses the endogenously produced truncated isoform. The truncated isoform itself neither binds to MHC class I molecules nor prevents the full-length US3 from interacting with MHC class I molecules. Instead, the truncated isoform associates with tapasin and competes with full-length US3 for binding to tapasin; thus, it suppresses the action of US3 that causes the disruption of the function of tapasin. Our results indicate that the truncated isoform of the US3 locus acts as a dominant negative regulator of full-length US3 activity. These data reflect the manner in which the virus has developed temporal survival strategies during viral infection against immune surveillance involving both CTLs and NK cells.
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Affiliation(s)
- Jinwook Shin
- Department of Biological Sciences, Seoul National University, San 56-1, Sillim-dong, Gwanak-Gu, Seoul 151-747, Korea
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Antoniou AN, Santos SG, Campbell EC, Lynch S, Arosa FA, Powis SJ. ERp57 interacts with conserved cysteine residues in the MHC class I peptide-binding groove. FEBS Lett 2007; 581:1988-92. [PMID: 17467700 DOI: 10.1016/j.febslet.2007.04.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 04/03/2007] [Accepted: 04/10/2007] [Indexed: 10/23/2022]
Abstract
The oxidoreductase ERp57 is a component of the major histocompatibility complex (MHC) class I peptide-loading complex. ERp57 can interact directly with MHC class I molecules, however, little is known about which of the cysteine residues within the MHC class I molecule are relevant to this interaction. MHC class I molecules possess conserved disulfide bonds between cysteines 101-164, and 203-259 in the peptide-binding and alpha3 domain, respectively. By studying a series of mutants of these conserved residues, we demonstrate that ERp57 predominantly associates with cysteine residues in the peptide-binding domain, thus indicating ERp57 has direct access to the peptide-binding groove of MHC class I molecules during assembly.
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Affiliation(s)
- Antony N Antoniou
- Cancer Sciences Division, University of Southampton School of Medicine, Southampton SO16 6YD, UK
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Abstract
The transporter associated with antigen processing (TAP) is a member of the ATP-binding cassette transporter family that specializes in delivering cytosolic peptides to class I molecules in the endoplasmic reticulum. The TAP is a major target of genetic alteration in tumours and disruption by viral inhibitors. In some species, TAP genes have co-evolved with MHC class I molecules to deliver peptides that are customised for particular alleles. In humans, MHC class I polymorphism determines the level of tapasin-mediated association with TAP and subsequent peptide optimisation within the peptide-loading complex (PLC). MHC class I molecules that still load peptides without complexing to the TAP might be more resistant to viral interference of the PLC and less sensitive to competition for TAP by other class I allotypes.
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Affiliation(s)
- James McCluskey
- Department of Microbiology and Immunology, The University of Melbourne, Victoria, Australia.
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Agrawal S, Reemtsma K, Bagiella E, Oluwole SF, Braunstein NS. Role of TAP-1 and/or TAP-2 antigen presentation defects in tumorigenicity of mouse melanoma. Cell Immunol 2004; 228:130-7. [PMID: 15219464 DOI: 10.1016/j.cellimm.2004.04.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2004] [Accepted: 04/20/2004] [Indexed: 11/30/2022]
Abstract
Mutations in transporters associated with antigen processing (TAP-1 and -2) required for the transport of cytosolic endogenous peptides to the endoplasmic reticulum correlate with increased metastatic potential and reduced host survival in several malignancies. To address the possible function of TAP as a "tumor suppressor" gene, we show that correction of TAP-1 and/or TAP-2 defects in B16 mouse melanoma enhanced the cell surface expression of MHC class I molecules and significantly reduced the rate of subcutaneous tumor growth and pulmonary metastatic burden. Cytotoxic assays confirmed increased sensitivity of TAP-1 and/or TAP-2 transfected clones of B16 melanoma to cytotoxic T lymphocytes. These results indicate that the expression of TAP limits the malignant potential of tumors with implications for CD8(+) T cell-based immunotherapy in controlling growth of certain TAP-deficient malignancies.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 2
- ATP Binding Cassette Transporter, Subfamily B, Member 3
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/immunology
- Animals
- Antigen Presentation/genetics
- Antigen Presentation/immunology
- Blotting, Northern
- Cytotoxicity Tests, Immunologic
- Flow Cytometry
- Histocompatibility Antigens Class I/immunology
- Immunotherapy
- Lung Neoplasms/genetics
- Lung Neoplasms/immunology
- Lung Neoplasms/pathology
- Male
- Melanoma, Experimental/genetics
- Melanoma, Experimental/immunology
- Melanoma, Experimental/pathology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- RNA, Neoplasm/chemistry
- RNA, Neoplasm/genetics
- T-Lymphocytes, Cytotoxic
- Transfection
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Affiliation(s)
- Shefali Agrawal
- Department of Surgery, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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Zernich D, Purcell AW, Macdonald WA, Kjer-Nielsen L, Ely LK, Laham N, Crockford T, Mifsud NA, Bharadwaj M, Chang L, Tait BD, Holdsworth R, Brooks AG, Bottomley SP, Beddoe T, Peh CA, Rossjohn J, McCluskey J. Natural HLA class I polymorphism controls the pathway of antigen presentation and susceptibility to viral evasion. ACTA ACUST UNITED AC 2004; 200:13-24. [PMID: 15226359 PMCID: PMC2213310 DOI: 10.1084/jem.20031680] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
HLA class I polymorphism creates diversity in epitope specificity and T cell repertoire. We show that HLA polymorphism also controls the choice of Ag presentation pathway. A single amino acid polymorphism that distinguishes HLA-B*4402 (Asp116) from B*4405 (Tyr116) permits B*4405 to constitutively acquire peptides without any detectable incorporation into the transporter associated with Ag presentation (TAP)-associated peptide loading complex even under conditions of extreme peptide starvation. This mode of peptide capture is less susceptible to viral interference than the conventional loading pathway used by HLA-B*4402 that involves assembly of class I molecules within the peptide loading complex. Thus, B*4402 and B*4405 are at opposite extremes of a natural spectrum in HLA class I dependence on the PLC for Ag presentation. These findings unveil a new layer of MHC polymorphism that affects the generic pathway of Ag loading, revealing an unsuspected evolutionary trade-off in selection for optimal HLA class I loading versus effective pathogen evasion.
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Affiliation(s)
- Danielle Zernich
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia
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