DOCSLIB.ORG

Essential Glycan-Dependent Interactions Optimize MHC Class I Peptide Loading

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Essential Glycan-Dependent Interactions Optimize MHC Class I Peptide Loading Essential glycan-dependent interactions optimize MHC class I peptide loading Pamela A. Wearscha, David R. Peapera, and Peter Cresswella,b,1 aDepartment of Immunobiology and bDepartment of Cell Biology and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520-8011 Contributed by Peter Cresswell, February 15, 2011 (sent for review January 5, 2011) In this study we sought to better understand the role of the (CNX). Both chaperones have a globular lectin-binding domain glycoprotein quality control machinery in the assembly of MHC and an extended arm known as the P-domain that binds specifi- class I molecules with high-affinity peptides. The lectin-like chap- cally to ERp57, a member of the protein disulfide isomerase (PDI) erone calreticulin (CRT) and the thiol oxidoreductase ERp57 partic- family. ERp57 has a four-domain architecture of abb′a′ in which fi ipate in the nal step of this process as part of the peptide-loading the first and last contain a CXXC active site. CRT and CNX work complex (PLC). We provide evidence for an MHC class I/CRT in- in concert with ERp57 to promote proper folding and disulfide termediate before PLC engagement and examine the nature of that bond formation of newly synthesized glycoproteins. Upon release chaperone interaction in detail. To investigate the mechanism of of the glycoprotein from CRT or CNX, its glycan is deglucosylated peptide loading and roles of individual components, we reconsti- tuted a PLC subcomplex, excluding the Transporter Associated with by GlsII and is no longer a substrate for the chaperones. If the Antigen Processing, from purified, recombinant proteins. ERp57 glycoprotein has not yet acquired its native structure, the enzyme disulfide linked to the class I-specific chaperone tapasin and CRT UDP-glucose:glycoprotein glucosyltransferase 1 (UGT1), a fold- were the minimal PLC components required for MHC class I as- ing sensor, reglucosylates it to reinitiate an interaction with CRT/ sociation and peptide loading. Mutations disrupting the interaction CNX/ERp57. However, a properly folded glycoprotein is not a of CRT with ERp57 or the class I glycan completely eliminated PLC substrate for UGT1 and can be exported to the Golgi. activity in vitro. By using the purified system, we also provide Important roles for CRT and ERp57 in MHC class I assembly direct evidence for a role for UDP-glucose:glycoprotein glucosyl- and PLC function have been established from studies of KO transferase 1 in MHC class I assembly. The recombinant Drosoph- mice and deficient cell lines (2, 3). In the absence of either ila enzyme reglucosylated MHC class I molecules associated with component, the cell surface expression and stability of MHC suboptimal ligands and allowed PLC reengagement and high- class I molecules are reduced. The cause of the defect has been fi af nity peptide exchange. Collectively, the data indicate that elucidated for ERp57-deficient cells. Tapasin forms a stable CRT in the PLC enhances weak tapasin/class I interactions in a man- disulfide-linked heterodimer with ERp57, which is required for ner that is glycan-dependent and regulated by UDP-glucose:glyco- the structural stability and optimal function of the PLC (4, 7, 8). protein glucosyltransferase 1. The disulfide linkage is between Cys95 of tapasin and Cys57 a protein folding | peptide editing of the ERp57 domain active site (9), and the dimer is further stabilized by noncovalent interactions between tapasin and the a′ domain active site (10). CRT interacts with both the HC glycan he assembly of MHC class I molecules is a critical step in the and the b′ domain of ERp57, but the nature and importance of Tgeneration of immune responses against viruses and tumors, and also a highly specialized example of glycoprotein folding in these interactions within the PLC are controversial, particularly – the endoplasmic reticulum (ER). MHC class I molecules display in regard to glycan-independent substrate binding (11 15). Fi- peptides representative of the cellular protein content to CD8+ nally, the potential roles of GlsII and UGT1 in regulating the T cells, and the stable association of the class I heavy chain (HC), CRT/class I interaction in the PLC have yet to be addressed. By using a variety of biochemical approaches, including re- β2-microglobulin (β2m), and a high-affinity 8- to 10-aa foreign peptide is essential for T-cell activation. As a result, a specialized constitution of a PLC subcomplex entirely from purified com- adaptation of the glycoprotein folding machinery has evolved to ponents, we have investigated the role of ER quality control ensure the loading of MHC class I molecules with optimal peptide components in MHC class I peptide loading. We demonstrate ligands. Following HC assembly with β2m, the empty heterodimer the CRT is recruited to and released from the PLC along with rapidly and stably associates with the peptide-loading complex class I molecules. By examination of the CRT/HC stoichiometry (PLC), which facilitates the final peptide-binding step (1). The and the HC glycosylation state, we found no evidence for glycan- functions of the MHC class I-specific components of the PLC are independent interactions within the PLC. Consistent with this, in fi β well de ned. Tapasin interacts with both the HC/ 2m dimer as vitro reconstitution of the PLC required the lectin- and ERp57- well as Transporter Associated with Antigen Processing (TAP), binding activities of CRT and could be enhanced by UGT1- thereby retaining the empty complexes in proximity to the peptide mediated glucosylation. Taken together, the data support impor- supply. More importantly, tapasin association stabilizes class I tant roles for CRT and the quality control machinery in regulating fi molecules and promotes loading with high-af nity peptides. class I peptide loading by the PLC. However, the optimal activity of tapasin requires the presence of calreticulin (CRT) and ERp57, two ER proteins involved in – general glycoprotein folding, in the PLC (2 4). Author contributions: P.A.W., D.R.P., and P.C. designed research; P.A.W. and D.R.P. per- The ER glycoprotein quality control machinery is a complex formed research; P.A.W., D.R.P., and P.C. analyzed data; and P.A.W. and P.C. wrote the system that uses the structural state of N-linked glycans to dic- paper. tate the fate of newly synthesized proteins (1, 5, 6). Initially, a The authors declare no conflict of interest. Glc3Man9GlcNAc2 glycan is transferred to polypeptides during Freely available online through the PNAS open access option. translocation and subsequently trimmed by glucosidase I (GlsI) 1To whom correspondence should be addressed. E-mail: [email protected]. and glucosidase II (GlsII) to a monoglucosylated glycan, which is This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. the substrate for the lectin-like chaperones CRT and calnexin 1073/pnas.1102524108/-/DCSupplemental. 4950–4955 | PNAS | March 22, 2011 | vol. 108 | no. 12 www.pnas.org/cgi/doi/10.1073/pnas.1102524108 Downloaded by guest on September 25, 2021 Results and Discussion to the conjugate with this assay. However, a significant portion of CRT Associates with MHC Class I HC/β2m Heterodimers Before these complexes likely dissociate during the extract preparation Incorporation into the PLC. Work from our laboratory has dem- given the relatively low affinity of CRT for glycosylated class I K ∼ μ onstrated that the tapasin/ERp57 conjugate associates with TAP HC ( d of 1 M) (14) and the rapid rate of dissociation de- ∼ in cells lacking expression of MHC class I HC or β2m (8, 16), termined from kinetic experiments (t1/2 of 10 min at 4 °C; Fig. suggesting that this core serves as a scaffold onto which the S1). Consistent with our projections, the addition of excess remaining PLC components assemble. Furthermore, the GlsII recombinant CRT to the lysis buffer enhanced HC association inhibitor castanospermine (CST) prevents the interaction of MHC with the conjugate (Fig. 1C), presumably because of preservation β class I molecules with the PLC in intact cells (17) and a cell-free of CRT/HC/ 2m complexes in the assembly pathway. In agree- ment, Del Cid et al. (11) have proposed a recruiting role for assay (4). This suggests that CRT escorts HC/β2m dimers to tapasin, but this has not been demonstrated experimentally. Ini- CRT in the PLC based on reduced class I association with the fi tially, we sought to identify PLC-independent complexes of HLA- PLC in CRT-de cient cells. However, that interpretation is B8 with CRT by using tapasin-negative .220.B8 cells. We prepared complicated by the analyses being performed at steady state, i.e., extracts from radiolabeled cells in the absence or presence of the effect of CRT on the class I /tapasin interaction may be a DSP, a chemical cross-linker, and performed sequential immu- result of PLC stabilization. Although the two effects cannot be noprecipitations to detect CRT-associated proteins. As shown in discriminated biochemically, CRT may serve an important role β Fig. 1A, a CRT/HC interaction was observed in untreated extracts for both. The discovery that an HC/ 2m/CRT assembly in- and stabilized by DSP. β m, which is not glycosylated, also coim- termediate exists provides the most direct evidence for CRT- 2 A B munoprecipitated with CRT from cross-linked cell extracts, mediated recruitment (Fig. 1 and ), whereas the coupling of known interactions between PLC components is sufficient to demonstrating the presence of CRT-associated HC/β2m hetero- dimers (Fig. 1A). To determine whether this complex exists in the support CRT-mediated stabilization of existing class I/ tapasin presence of the PLC, we performed tapasin immunodepletions interactions (1). from radiolabeled .220.B8.Tpsn cells.
Load more

Recommended publications
  • Processing and Presentation of Glycoproteins in the MHC Class I and II Antigen Presentation Pathways Denise Golgher, Tim Elliott and Mark Howarth
    CHAPTER 11 Processing and Presentation of Glycoproteins in the MHC Class I and II Antigen Presentation Pathways Denise Golgher, Tim Elliott and Mark Howarth Abstract D8+ and CD4+ T cells are stimulated by peptides bound to MHC class I and II respec- tively. The processing pathways for the generation of class I or class II binding peptides C are specialized in surveying different intracellular compartments. While class I peptide loading occurs in the ER, class II loading occurs in the endocytic compartments. Many of the peptides generated in either compartment are derived from glycoproteins from normal or malignant cells or from intracellular or extracellular pathogens. In a given polypeptide there are potentially many T cell epitopes but only a few actually bind to the MHC molecules and generate a T cell response, while many others are cryptic. The carbohydrate moiety present in glycoproteins has been shown to influence the antigen processing pathway and generation of T cell epitopes in different ways. It can stabilize a certain three-dimensional conformation of the glycoprotein determining which sites are more accessible to proteases, it can hinder the access of proteases or block certain sites, it can target exogenous antigen to different antigen presenting cells and it can also be part of the epitope that will stimulate T cells. Changes in glycosylation patterns are common in malignancies, age and pathological mechanisms. These changes have the potential to alter the hierarchy of peptides that will bind to MHC molecules and induce a T cell response that would otherwise be cryptic, causing the onset of undesirable immune responses as is the case for autoimmune processes.
    [Show full text]
  • Research Article
    Immunology and Cell Biology (2005) 83, 475–482 doi:10.1111/j.1440-1711.2005.01354.x Research Article Identification of domain boundaries within the N-termini of TAP1 and TAP2 and their importance in tapasin binding and tapasin-mediated increase in peptide loading of MHC class I ERIK PROCKO,1 GAYATRI RAGHURAMAN,3 DON C WILEY,1,2 MALINI RAGHAVAN3 and RACHELLE GAUDET1 1Department of Molecular and Cellular Biology and 2Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts and 3Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA Summary Before exit from the endoplasmic reticulum (ER), MHC class I molecules transiently associate with the transporter associated with antigen processing (TAP1/TAP2) in an interaction that is bridged by tapasin. TAP1 and TAP2 belong to the ATP-binding cassette (ABC) transporter family, and are necessary and sufficient for peptide translocation across the ER membrane during loading of MHC class I molecules. Most ABC transporters comprise a transmembrane region with six membrane-spanning helices. TAP1 and TAP2, however, contain additional N-terminal sequences whose functions may be linked to interactions with tapasin and MHC class I molecules. Upon expression and purification of human TAP1/TAP2 complexes from insect cells, proteolytic fragments were identified that result from cleavage at residues 131 and 88 of TAP1 and TAP2, respectively. N-Terminally truncated TAP variants lacking these segments retained the ability to bind peptide and nucleotide substrates at a level comparable to that of wild-type TAP. The truncated constructs were also capable of peptide translocation in vitro, although with reduced efficiency.
    [Show full text]
  • PDIA3 Recombinant Protein Description Product Info
    9853 Pacific Heights Blvd. Suite D. San Diego, CA 92121, USA Tel: 858-263-4982 Email: [email protected] 32-2652: PDIA3 Recombinant Protein ERp57,ERp60,ERp61,GRP57,GRP58,HsT17083,P58,PI-PLC,ER60,Protein disulfide-isomerase A3,Disulfide Alternative isomerase ER-60,Endoplasmic reticulum resident protein 60,ER protein 60,58 kDa microsomal Name : protein,Endoplasmic reticulum resident protein 57, Description Source : Escherichia Coli. PDIA3 Human Recombinant produced in E.Coli is a single, non-glycosylated polypeptide chain containing 518 amino acids (25-505 a.a.) and having a molecular wieght of 58.5 kDa. The PDIA3 is fused to 37 a.a. His-Tag at N-terminus and purified by proprietary chromatographic techniques. PDIA3 is an enzyme that belongs to the endoplasmic reticulum and interacts with lectin chaperones calreticulin and calnexin to modulate folding of newly synthesized glycoproteins. PDIA3 has protein disulfide isomerase activity. Complexes of lectins and PDIA3 mediate protein folding by promoting formation of disulfide bonds in their glycoprotein substrates. PDIA3 is expressed in the lumbar spinal cord from rats submitted to peripheral lesion during neonatal period. PDIA3 interacts with thiazide-sensitive sodium-chloride cotransporter in the kidney and is induced by glucose deprivation. PDIA3 is part of the major histocompatibility complex (MHC) class I peptide-loading complex (TAP1), which is important for formation of the final antigen conformation and export from the endoplasmic reticulum to the cell surface. Product Info Amount : 25 µg Purification : Greater than 95.0% as determined by SDS-PAGE. The PDIA3 protein solution contains 20mM Tris-HCl, pH-8, 1mM DTT, 0.1M NaCl and 10% Content : glycerol.
    [Show full text]
  • Tapasin Gene Polymorphism in Systemic Onset Juvenile Rheumatoid Arthritis
    Available online http://arthritis-research.com/content/7/2/R285 ResearchVol 7 No 2 article Open Access Tapasin gene polymorphism in systemic onset juvenile rheumatoid arthritis: a family-based case–control study Hulya Bukulmez1,2,3,4, Mark Fife5, Monica Tsoras1, Susan D Thompson1, Natalie A Twine5, Patricia Woo5, Jane M Olson2, Robert C Elston2, David N Glass1 and Robert A Colbert1 1William S. Rowe Division of Pediatric Rheumatology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA 2Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, USA 3Department of Genetics, Case Western Reserve University, Cleveland, Ohio, USA 4Pediatric Rheumatology, Pediatrics, Metro Health Medical Center, Case Western Reserve University, Cleveland, Ohio, USA 5The Center for Pediatric and Adolescent Rheumatology, University College London, London, UK Corresponding author: Hulya Bukulmez, [email protected] Received: 13 Mar 2004 Revisions requested: 13 May 2004 Revisions received: 17 Nov 2004 Accepted: 22 Nov 2004 Published: 11 Jan 2005 Arthritis Res Ther 2005, 7:R285-R290 (DOI 10.1186/ar1480)http://arthritis-research.com/content/7/2/R285 © 2005 Bukulmez et al., licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/ 2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is cited. Abstract Juvenile rheumatoid arthritis (JRA) comprises a group of chronic the systemic onset subtype of JRA. Two independent JRA systemic inflammatory disorders that primarily affect joints and cohorts were used, one recruited from the Rheumatology Clinic can cause long-term disability.
    [Show full text]
  • Cloning and Functional Characterization of a Subunit of the Transporter Associated with Antigen Processing
    Proc. Natl. Acad. Sci. USA Vol. 94, pp. 8708–8713, August 1997 Immunology Cloning and functional characterization of a subunit of the transporter associated with antigen processing SULING LI*, HANS-OLOV SJO¨GREN*, ULF HELLMAN†,RALF F. PETTERSSON‡, AND PING WANG*‡§ *Tumor Immunology, Lund University, Box 7031, S-22007 Lund, Sweden; ‡Ludwig Institute for Cancer Research, Stockholm Branch, Box 240, S-171 77 Stockholm, Sweden, and †Uppsala Branch, Box 595, S-75124 Uppsala, Sweden Communicated by James E. Rothman, Memorial Sloan–Kettering Cancer Center, New York, NY, May 23, 1997 (received for review May 7, 1997) ABSTRACT The transporter associated with antigen pro- In addition to functioning as a peptide transporter, a phys- cessing (TAP) is essential for the transport of antigenic ical association between TAP1 and class I heavy chain (HC)y peptides across the membrane of the endoplasmic reticulum. b2-microglobulin (b2-m) dimer has been demonstrated (14, In addition, TAP interacts with major histocompatibility 15). The binding of class I HCyb2-m to TAP1 is not required complex class I heavy chain (HC)yb2-microglobulin (b2-m) for the peptide translocation, so the binding of peptides to class dimers. We have cloned a cDNA encoding a TAP1y2- I molecules is thought to be facilitated by association of associated protein (TAP-A) corresponding in size and bio- assembled HCyb2-m heterodimers with the TAP complex chemical properties to tapasin, which was recently suggested (14–16). Recently, it has been found that a point mutation of to be involved in class I–TAP interaction (Sadasivan, B., threonine 134 to lysine (T134K) in the HLA-A2.1 makes the Lehner, P.
    [Show full text]
  • Tapasin Enhances MHC Class I Peptide Presentation According to Peptide Half-Life
    Tapasin enhances MHC class I peptide presentation according to peptide half-life Mark Howarth*†‡, Anthony Williams†, Anne B. Tolstrup§¶, and Tim Elliott†ʈ *Medical Research Council Human Immunology Unit, Oxford University, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom; †Cancer Sciences Division, Southampton University, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; and §Inoxell, Kogle Alle´5, DK-2970 Hoersholm, Denmark Edited by Stanley G. Nathenson, Albert Einstein College of Medicine, Bronx, NY, and approved June 24, 2004 (received for review September 30, 2003) Understanding how peptides are selected for presentation by MHC Materials and Methods class I is crucial to vaccination strategies based on cytotoxic T General Reagents. Peptides were synthesized by using F-moc lymphocyte priming. We have studied this selection of the MHC chemistry (Peptide Protein Research, Eastleigh, U.K.) and were class I peptide repertoire in terms of the presentation of a series of Ͼ95% pure by HPLC and mass spectrometry. Serum-free media individual peptides with a wide range of binding to MHC class I. was AIM-V (Sigma). This series was expressed as minigenes, and the presentation of each peptide variant was determined with the same MHC class I Antibodies. 25-D1.16 (D1) recognizes H2-Kb-SIINFEKL (20), peptide-specific antibody. In wild-type cells, the hierarchy of pre- kindly provided by R. Germain (National Institutes of Health, sentation followed peptide half-life. This hierarchy broke down in Bethesda). Y3 recognizes a conformation-sensitive epitope of cells lacking tapasin but not in cells lacking calreticulin or in cells H2-Kb. 148.3 recognizes human TAP1, kindly provided by R.
    [Show full text]
  • Polymorphisms of HLA-B: Influences on Assembly and Immunity
    Available online at www.sciencedirect.com ScienceDirect Polymorphisms of HLA-B: influences on assembly and immunity 1 2 2 Eli Olson , Jie Geng and Malini Raghavan The major histocompatibility class I (MHC-I) complex functions biology of HLA-B, the most polymorphic of the HLA-I in innate and adaptive immunity, mediating surveillance of the genes. subcellular environment. In humans, MHC-I heavy chains are encoded by three genes: the human leukocyte antigen (HLA)-A, Canonical MHC-I assembly in the ER HLA-B, and HLA-C. These genes are highly polymorphic, MHC-I assembly is highly regulated and involves the which results in the expression, typically, of six different HLA coordinated action of a number of proteins [1]. Canoni- class I (HLA-I) proteins on the cell surface, and the presentation + cal peptide loading occurs in the ER, beginning with of diverse peptide antigens to CD8 T cells for broad MHC-I heavy chain dimerization with the invariant surveillance against many pathogenic conditions. Recent b2-microglobulin (b2m) light chain. The heavy chain- studies of HLA-B allotypes show that the polymorphisms, not b2m dimer is generally (but not always) unstable in surprisingly, also significantly impact protein folding and the absence of peptides [2,3 ], and associates with the assembly pathways. The use of non-canonical assembly routes peptide loading complex (PLC) which comprises the and the generation of non-canonical HLA-B conformers has chaperone proteins calreticulin and ERp57, tapasin, consequences for immune receptor interactions and disease and the transporter associated with antigen processing therapies. (TAP). Peptides that are processed by the cytoplasmic proteasome are bound by and transported into the ER Addresses 1 lumen by heterodimeric TAP1/TAP2 complexes, the Graduate Program in Immunology, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA two subunits of TAP.
    [Show full text]
  • MHC I Chaperone Complexes Shaping Immunity
    Available online at www.sciencedirect.com ScienceDirect MHC I chaperone complexes shaping immunity Christoph Thomas and Robert Tampe´ Major histocompatibility complex class I (MHC I) molecules by displaying peptides at the cell surface on MHC I present peptides on the surface of most nucleated cells and heterodimers, which consist of the peptide-binding, poly- allow the immune system to detect and eliminate infected or morphic heavy chain, and the smaller b2-microglobulin malignantly transformed cells. The peptides are derived from (b2m). By scanning the pMHC I complexes via T-cell + endogenous proteins by proteasomal degradation or aberrant receptors (TCRs), antigen-experienced CD8 T lympho- translation, and are translocated from the cytosol into the cytes of the adaptive immune system are able to recognize endoplasmic reticulum (ER) by the transporter associated with foreign, antigenic peptides, and destroy infected or cancer- antigen processing (TAP), a central component of the peptide- ous cells [1,2]. The peptides presented by MHC I are loading complex (PLC). The peptides are subsequently predominantly a small subset of the protein fragments processed by ER-resident aminopeptidases (ERAP1/2) and generated by proteasomal degradation in the cytosol; they loaded onto MHC I. This loading, however, does not happen are selectively transported into the ER where theloading of indiscriminately: in a process called peptide editing or peptide the MHC I with peptidestakesplace. Peptidetranslocation proofreading, the MHC I-specific chaperones tapasin and into the ER is carried out by the heterodimeric ABC (ATP- TAPBPR (TAP-binding protein-related) catalyze the selection of binding cassette) transporter TAP [3]. Inside the ER, high-affinity peptides and stable peptide-MHC I (pMHC I) peptides can be further trimmed by the aminopeptidases complexes.
    [Show full text]
  • Critical Review of Existing MHC I Immunopeptidome Isolation Methods
    molecules Review Critical Review of Existing MHC I Immunopeptidome Isolation Methods Alexandr Kuznetsov 1, Alice Voronina 1 , Vadim Govorun 1,2 and Georgij Arapidi 2,3,4,* 1 Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia; [email protected] (A.K.); [email protected] (A.V.); [email protected] (V.G.) 2 Department of Molecular and Translational Medicine, Moscow Institute of Physics and Technology (State University), 141701 Dolgoprudny, Russia 3 Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia 4 Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 117997 Moscow, Russia * Correspondence: [email protected]; Tel.: +7-926-471-1420 Academic Editor: Luca D. D’Andrea Received: 5 October 2020; Accepted: 17 November 2020; Published: 19 November 2020 Abstract: Major histocompatibility complex class I (MHC I) plays a crucial role in the development of adaptive immune response in vertebrates. MHC molecules are cell surface protein complexes loaded with short peptides and recognized by the T-cell receptors (TCR). Peptides associated with MHC are named immunopeptidome. The MHC I immunopeptidome is produced by the proteasome degradation of intracellular proteins. The knowledge of the immunopeptidome repertoire facilitates the creation of personalized antitumor or antiviral vaccines. A huge number of publications on the immunopeptidome diversity of different human and mouse biological samples—plasma, peripheral blood mononuclear cells (PBMCs), and solid tissues, including tumors—appeared in the scientific journals in the last decade.
    [Show full text]
  • Chaperones of the Class I Peptide-Loading Complex Facilitate the Constitutive Presentation of Endogenous Antigens on HLA-DP84GGPM87 T
    Journal of Autoimmunity 102 (2019) 114–125 Contents lists available at ScienceDirect Journal of Autoimmunity journal homepage: www.elsevier.com/locate/jautimm Chaperones of the class I peptide-loading complex facilitate the constitutive presentation of endogenous antigens on HLA-DP84GGPM87 T Mark Anczurowskia,b, Kenji Sugataa, Yukiko Matsunagaa, Yuki Yamashitaa, Chung-Hsi Wanga,b, Tingxi Guoa, Kenji Murataa, Hiroshi Saijoa, Yuki Kagoyaa, Kayoko Sasoa, Marcus O. Butlera,b,c, ∗ Naoto Hiranoa,b, a Tumor Immunotherapy Program, Campbell Family Institute for Breast Cancer Research, Campbell Family Cancer Research Institute, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, M5G 2M9, Canada b Department of Immunology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada c Department of Medicine, University of Toronto, Toronto, Ontario, M5S 1A8, Canada ABSTRACT Recent work has delineated key differences in the antigen processing and presentation mechanisms underlying HLA-DP alleles encoding glycine at position 84 of the DPβ chain (DP84GGPM87). These DPs are unable to associate with the class II-associated Ii peptide (CLIP) region of the invariant chain (Ii) chaperone early in the endocytic pathway, leading to continuous presentation of endogenous antigens. However, little is known about the chaperone support involved in the loading of these endogenous antigens onto DP molecules. Here, we demonstrate the proteasome and TAP dependency of this pathway and reveal the ability of HLA classIto compete with DP84GGPM87 for the presentation of endogenous antigens, suggesting that shared subcellular machinery may exist between the two classes of HLA. We identify physical interactions of prototypical class I-associated chaperones with numerous DP alleles, including TAP2, tapasin, ERp57, calnexin, and calreticulin, using a conventional immunoprecipitation and immunoblot approach and confirm the existence of these interactions in vivo through the use of the BioID2 proximal biotinylation system in human cells.
    [Show full text]
  • In the Peptide-Loading Complex Mechanistic Basis for Epitope
    Mechanistic Basis for Epitope Proofreading in the Peptide-Loading Complex Gerda Fleischmann, Olivier Fisette, Christoph Thomas, Ralph Wieneke, Franz Tumulka, Clemens Schneeweiss, This information is current as Sebastian Springer, Lars V. Schäfer and Robert Tampé of September 24, 2021. J Immunol 2015; 195:4503-4513; Prepublished online 28 September 2015; doi: 10.4049/jimmunol.1501515 http://www.jimmunol.org/content/195/9/4503 Downloaded from Supplementary http://www.jimmunol.org/content/suppl/2015/09/28/jimmunol.150151 Material 5.DCSupplemental http://www.jimmunol.org/ References This article cites 59 articles, 16 of which you can access for free at: http://www.jimmunol.org/content/195/9/4503.full#ref-list-1 Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision by guest on September 24, 2021 • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2015 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Mechanistic Basis for Epitope Proofreading in the Peptide-Loading Complex Gerda Fleischmann,* Olivier Fisette,† Christoph Thomas,* Ralph Wieneke,* Franz Tumulka,* Clemens Schneeweiss,‡ Sebastian Springer,‡ Lars V.
    [Show full text]
  • Soluble Tapasin Restores MHC Class I Expression and Function in the Tapasin-Negative Cell Line .220
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Immunity, Vol. 8, 221±231, February, 1998, Copyright 1998 by Cell Press Soluble Tapasin Restores MHC Class I Expression and Function in the Tapasin-Negative Cell Line .220 Paul J. Lehner,² Michael J. Surman, associate with the ER-resident chaperone calnexin and Peter Cresswell* (Noessner and Parham, 1995). Calnexin is not obligatory Section of Immunobiology for class I assembly; however, as in a calnexin-negative Howard Hughes Medical Institute cell line, peptide loading, assembly, and function of Yale University School of Medicine class I molecules appear to be normal (Sadasivan et al., New Haven, Connecticut 06510 1995; Scott and Dawson, 1995). In human cells, class I binding to b2-microglobulin (b2m) is thought to cause dissociation of calnexin (Sadasivan et al., 1996). The Summary class I±b2m heterodimer then associates with TAP and forms part of a large ER complex, ªthe TAP complex,º Tapasin forms a bridge between TAP (transporters the minimal components of which include TAP1 and associated with antigen processing) and MHC class I TAP2, MHC class I heavy chains, b2m, the soluble ER- molecules and plays a critical role in class I assembly. resident chaperone calreticulin, and the newly identified In its absence, TAP and class I do not associate, and protein tapasin (Sadasivan et al., 1996; Solheim et al., class I cell surface expression is reduced. We now 1997). Although the precise order of events governing identify two independent functions for tapasin. Ta- the assembly of this complex is not yet understood, pasin increases TAP levels and allows more peptide studies on mutant cell lines have been extremely useful to be translocated to the endoplasmic reticulum.
    [Show full text]