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Vollmers S, Lobermeyer A, Körner C. The New Kid on the Block: HLA-C, a Key Regulator of Natural Killer Cells in Viral Immunity. Cells 2021; 10:cells10113108. [PMID: 34831331 PMCID: PMC8620871 DOI: 10.3390/cells10113108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 11/01/2022] Open
Abstract
The human leukocyte antigen system (HLA) is a cluster of highly polymorphic genes essential for the proper function of the immune system, and it has been associated with a wide range of diseases. HLA class I molecules present intracellular host- and pathogen-derived peptides to effector cells of the immune system, inducing immune tolerance in healthy conditions or triggering effective immune responses in pathological situations. HLA-C is the most recently evolved HLA class I molecule, only present in humans and great apes. Differentiating from its older siblings, HLA-A and HLA-B, HLA-C exhibits distinctive features in its expression and interaction partners. HLA-C serves as a natural ligand for multiple members of the killer-cell immunoglobulin-like receptor (KIR) family, which are predominately expressed by natural killer (NK) cells. NK cells are crucial for the early control of viral infections and accumulating evidence indicates that interactions between HLA-C and its respective KIR receptors determine the outcome and progression of viral infections. In this review, we focus on the unique role of HLA-C in regulating NK cell functions and its consequences in the setting of viral infections.
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Tanikawa Y, Kanemura S, Ito D, Lin Y, Matsusaki M, Kuroki K, Yamaguchi H, Maenaka K, Lee YH, Inaba K, Okumura M. Ca 2+ Regulates ERp57-Calnexin Complex Formation. Molecules 2021; 26:molecules26102853. [PMID: 34064874 PMCID: PMC8151781 DOI: 10.3390/molecules26102853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/01/2021] [Accepted: 05/09/2021] [Indexed: 11/20/2022] Open
Abstract
ERp57, a member of the protein disulfide isomerase family, is a ubiquitous disulfide catalyst that functions in the oxidative folding of various clients in the mammalian endoplasmic reticulum (ER). In concert with ER lectin-like chaperones calnexin and calreticulin (CNX/CRT), ERp57 functions in virtually all folding stages from co-translation to post-translation, and thus plays a critical role in maintaining protein homeostasis, with direct implication for pathology. Here, we present mechanisms by which Ca2+ regulates the formation of the ERp57-calnexin complex. Biochemical and isothermal titration calorimetry analyses revealed that ERp57 strongly interacts with CNX via a non-covalent bond in the absence of Ca2+. The ERp57-CNX complex not only promoted the oxidative folding of human leukocyte antigen heavy chains, but also inhibited client aggregation. These results suggest that this complex performs both enzymatic and chaperoning functions under abnormal physiological conditions, such as Ca2+ depletion, to effectively guide proper oxidative protein folding. The findings shed light on the molecular mechanisms underpinning crosstalk between the chaperone network and Ca2+.
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Affiliation(s)
- Yuya Tanikawa
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan; (Y.T.); (S.K.); (H.Y.)
| | - Shingo Kanemura
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan; (Y.T.); (S.K.); (H.Y.)
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramakiaza Aoba, Aoba-ku, Sendai 980-8578, Japan;
| | - Dai Ito
- Department of Brain and Cognitive Science, Daegu Gyeongbuk Institute of Science and Technology, 333 Techno Jungang Daero, Daegu 42988, Korea;
| | - Yuxi Lin
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, 162 Yeongudanji-ro, Ochang, Cheongju 28119, Korea; (Y.L.); (Y.-H.L.)
| | - Motonori Matsusaki
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramakiaza Aoba, Aoba-ku, Sendai 980-8578, Japan;
- Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Kimiko Kuroki
- Laboratory of Biomolecular Science, Faculty of Pharmaceutical Sciences, Hokkaido University, Nishi 6, Kita 12, Kita-ku, Sapporo 060-0812, Japan; (K.K.); (K.M.)
| | - Hiroshi Yamaguchi
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan; (Y.T.); (S.K.); (H.Y.)
| | - Katsumi Maenaka
- Laboratory of Biomolecular Science, Faculty of Pharmaceutical Sciences, Hokkaido University, Nishi 6, Kita 12, Kita-ku, Sapporo 060-0812, Japan; (K.K.); (K.M.)
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences and Global Station for Biosurfaces and Drug Discovery, Hokkaido University, Nishi 6, Kita 12, Kita-ku, Sapporo 060-0812, Japan
| | - Young-Ho Lee
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, 162 Yeongudanji-ro, Ochang, Cheongju 28119, Korea; (Y.L.); (Y.-H.L.)
- Research Headquarters, Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu 41068, Korea
- Bio-Analytical Science, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Korea
- Graduate School of Analytical Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan;
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramakiaza Aoba, Aoba-ku, Sendai 980-8578, Japan;
- Fusion Oriented Research for Disruptive Science and Technology, Japan Science Technology Agency, Chiyoda-ku, Tokyo 102-0075, Japan
- Correspondence: ; Tel.: +81-22-795-5764
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Hirayama C, Machida K, Noi K, Murakawa T, Okumura M, Ogura T, Imataka H, Inaba K. Distinct roles and actions of protein disulfide isomerase family enzymes in catalysis of nascent-chain disulfide bond formation. iScience 2021; 24:102296. [PMID: 33855279 PMCID: PMC8024706 DOI: 10.1016/j.isci.2021.102296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/13/2021] [Accepted: 03/05/2021] [Indexed: 12/04/2022] Open
Abstract
The mammalian endoplasmic reticulum (ER) harbors more than 20 members of the protein disulfide isomerase (PDI) family that act to maintain proteostasis. Herein, we developed an in vitro system for directly monitoring PDI- or ERp46-catalyzed disulfide bond formation in ribosome-associated nascent chains of human serum albumin. The results indicated that ERp46 more efficiently introduced disulfide bonds into nascent chains with a short segment exposed outside the ribosome exit site than PDI. Single-molecule analysis by high-speed atomic force microscopy further revealed that PDI binds nascent chains persistently, forming a stable face-to-face homodimer, whereas ERp46 binds for a shorter time in monomeric form, indicating their different mechanisms for substrate recognition and disulfide bond introduction. Thus, ERp46 serves as a more potent disulfide introducer especially during the early stages of translation, whereas PDI can catalyze disulfide formation when longer nascent chains emerge out from ribosome. We developed an in vitro system for monitoring nascent-chain disulfide formation High-speed AFM visualized PDI and ERp46 molecules acting on nascent chains PDI persistently holds nascent chains via dimerization for disulfide introduction ERp46 rapidly introduces disulfide bonds to nascent chains via short-time binding
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Affiliation(s)
- Chihiro Hirayama
- Institute of Multidisciplinary Research for Advanced Materials, Katahira 2-1-1, Aoba-ku, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Kodai Machida
- Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280, Japan
| | - Kentaro Noi
- Institute for NanoScience Design, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Tadayoshi Murakawa
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, 226-8503, Japan
| | - Masaki Okumura
- Institute of Multidisciplinary Research for Advanced Materials, Katahira 2-1-1, Aoba-ku, Tohoku University, Sendai, Miyagi 980-8577, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Teru Ogura
- Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan.,Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 862-0973, Japan
| | - Hiroaki Imataka
- Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Katahira 2-1-1, Aoba-ku, Tohoku University, Sendai, Miyagi 980-8577, Japan
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4
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Kanemura S, Matsusaki M, Inaba K, Okumura M. PDI Family Members as Guides for Client Folding and Assembly. Int J Mol Sci 2020; 21:ijms21249351. [PMID: 33302492 PMCID: PMC7763558 DOI: 10.3390/ijms21249351] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/06/2020] [Accepted: 12/06/2020] [Indexed: 12/27/2022] Open
Abstract
Complicated and sophisticated protein homeostasis (proteostasis) networks in the endoplasmic reticulum (ER), comprising disulfide catalysts, molecular chaperones, and their regulators, help to maintain cell viability. Newly synthesized proteins inserted into the ER need to fold and assemble into unique native structures to fulfill their physiological functions, and this is assisted by protein disulfide isomerase (PDI) family. Herein, we focus on recent advances in understanding the detailed mechanisms of PDI family members as guides for client folding and assembly to ensure the efficient production of secretory proteins.
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Affiliation(s)
- Shingo Kanemura
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan;
| | - Motonori Matsusaki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan; (M.M.); (K.I.)
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramakiaza Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan; (M.M.); (K.I.)
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramakiaza Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
- Correspondence: ; Tel.: +81-22-217-5628
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5
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Yang S, Shergalis A, Lu D, Kyani A, Liu Z, Ljungman M, Neamati N. Design, Synthesis, and Biological Evaluation of Novel Allosteric Protein Disulfide Isomerase Inhibitors. J Med Chem 2019; 62:3447-3474. [PMID: 30759340 DOI: 10.1021/acs.jmedchem.8b01951] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Protein disulfide isomerase (PDI) is responsible for nascent protein folding in the endoplasmic reticulum (ER) and is critical for glioblastoma survival. To improve the potency of lead PDI inhibitor BAP2 (( E)-3-(3-(4-hydroxyphenyl)-3-oxoprop-1-en-1-yl)benzonitrile), we designed and synthesized 67 analogues. We determined that PDI inhibition relied on the A ring hydroxyl group of the chalcone scaffold and cLogP increase in the sulfonamide chain improved potency. Docking studies revealed that BAP2 and analogues bind to His256 in the b' domain of PDI, and mutation of His256 to Ala abolishes BAP2 analogue activity. BAP2 and optimized analogue 59 have modest thiol reactivity; however, we propose that PDI inhibition by BAP2 analogues depends on the b' domain. Importantly, analogues inhibit glioblastoma cell growth, induce ER stress, increase expression of G2M checkpoint proteins, and reduce expression of DNA repair proteins. Cumulatively, our results support inhibition of PDI as a novel strategy to treat glioblastoma.
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Affiliation(s)
- Suhui Yang
- Department of Medicinal Chemistry, College of Pharmacy, Rogel Cancer Center , University of Michigan , North Campus Research Complex, 1600 Huron Parkway , Ann Arbor , Michigan 48109 , United States
| | - Andrea Shergalis
- Department of Medicinal Chemistry, College of Pharmacy, Rogel Cancer Center , University of Michigan , North Campus Research Complex, 1600 Huron Parkway , Ann Arbor , Michigan 48109 , United States
| | - Dan Lu
- Department of Medicinal Chemistry, College of Pharmacy, Rogel Cancer Center , University of Michigan , North Campus Research Complex, 1600 Huron Parkway , Ann Arbor , Michigan 48109 , United States
| | - Anahita Kyani
- Department of Medicinal Chemistry, College of Pharmacy, Rogel Cancer Center , University of Michigan , North Campus Research Complex, 1600 Huron Parkway , Ann Arbor , Michigan 48109 , United States
| | - Ziwei Liu
- Department of Medicinal Chemistry, College of Pharmacy, Rogel Cancer Center , University of Michigan , North Campus Research Complex, 1600 Huron Parkway , Ann Arbor , Michigan 48109 , United States
| | - Mats Ljungman
- Department of Radiation Oncology Rogel Cancer Center , University of Michigan Medical School and Rogel Cancer Center, School of Public Health , Ann Arbor , Michigan 48109 , United States
| | - Nouri Neamati
- Department of Medicinal Chemistry, College of Pharmacy, Rogel Cancer Center , University of Michigan , North Campus Research Complex, 1600 Huron Parkway , Ann Arbor , Michigan 48109 , United States
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Eggleton P, Bremer E, Dudek E, Michalak M. Calreticulin, a therapeutic target? Expert Opin Ther Targets 2016; 20:1137-47. [DOI: 10.1517/14728222.2016.1164695] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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Abstract
The mammalian immune system has evolved to display peptides derived from microbial antigens to immune effector cells. Liberated from the intact antigens through distinct proteolytic mechanisms, these peptides are subsequently transported to the cell surface while bound to chaperone-like receptors known as major histocompatibility complex molecules. These complexes are then scrutinized by T-cells that express receptors with specificity for specific major histocompatibility complex-peptide complexes. In normal uninfected cells, this process of antigen processing and presentation occurs continuously, with the resultant array of self-antigen-derived peptides displayed on the surface of these cells. Changes in this cellular peptide array alert the immune system to changes in the intracellular environment that may be associated with infection, oncogenesis or other abnormal cellular processes, resulting in a cascade of events that result in the elimination of the abnormal cell. Since peptides play such an essential role in informing the immune system of infection with viral or microbial pathogens and the transformation of cells in malignancy, the tools of proteomics, in particular mass spectrometry, are ideally suited to study these immune responses at a molecular level. Recent advances in studies of immune responses that have utilized mass spectrometry and associated technologies are reviewed. The authors gaze into the future and look at current challenges and where proteomics will impact in immunology over the next 5 years.
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Affiliation(s)
- Nicholas A Williamson
- The University of Melbourne, Department of Biochemistry & Molecular Biology, The Bio21 Molecular Science & Biotechnology Institute, 3010, Victoria, Australia.
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8
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Walker AK, Soo KY, Levina V, Talbo GH, Atkin JD. N-linked glycosylation modulates dimerization of protein disulfide isomerase family A member 2 (PDIA2). FEBS J 2012; 280:233-43. [PMID: 23167757 DOI: 10.1111/febs.12063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/30/2012] [Accepted: 11/08/2012] [Indexed: 02/03/2023]
Abstract
Protein disulfide isomerase (PDI) family members are important enzymes for the correct folding and maturation of proteins that transit or reside in the endoplasmic reticulum (ER). The human PDI family comprises at least 19 members that differ in cell type expression, substrate specificity and post-translational modifications. PDI family A member 2 (PDIA2, previously known as PDIp) has a similar domain structure to prototypical PDI (also known as PDIA1), but the function and post-translational modifications of PDIA2 remain poorly understood. Unlike most PDI family members, PDIA2 contains three predicted N-linked glycosylation sites. By site-directed mutagenesis and enzymatic deglycosylation, we show here that all three Asn residues within the potential N-linked glycosylation sites of human PDIA2 (N127, N284 and N516) are glycosylated in human cells. Furthermore, mutation of N284 to glycosylation-null Gln increases formation of a highly stable disulfide-bonded PDIA2 dimer. Nevertheless, in HeLa cells, both wild-type and N127/284/516Q mutant PDIA2 proteins localize to the ER, but not the ER-Golgi intermediate compartment, suggesting that glycosylation is important for PDIA2 protein-protein interactions but not subcellular localization. Finally, we identified human major histocompatibility complex class 1 antigens (HLA-A,B,C) as potential binding partners of PDIA2, suggesting an involvement for PDIA2 in antigen presentation in addition to its previously described roles in autoimmunity and Parkinson's disease. These results further characterize this poorly defined member of the PDI family.
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Affiliation(s)
- Adam K Walker
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
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9
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What is the role of alternate splicing in antigen presentation by major histocompatibility complex class I molecules? Immunol Res 2010; 46:32-44. [PMID: 19830395 DOI: 10.1007/s12026-009-8123-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The expression of major histocompatibility complex (MHC) class I molecules on the cell surface is critical for recognition by cytotoxic T lymphocytes (CTL). This recognition event leads to destruction of cells displaying MHC class I-viral peptide complexes or cells displaying MHC class I-mutant peptide complexes. Before they can be transported to the cell surface, MHC class I molecules must associate with their peptide ligand in the endoplasmic reticulum (ER) of the cell. Within the ER, numerous proteins assist in the appropriate assembly and folding of MHC class I molecules. These include the heterodimeric transporter associated with antigen processing (TAP1 and TAP2), the heterodimeric chaperone-oxidoreductase complex of tapasin and ERp57 and the general ER chaperones calreticulin and calnexin. Each of these accessory proteins has a well-defined role in antigen presentation by MHC class I molecules. However, alternate splice forms of MHC class I heavy chains, TAP and tapasin, have been reported suggesting additional complexity to the picture of antigen presentation. Here, we review the importance of these different accessory proteins and the progress in our understanding of alternate splicing in antigen presentation.
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10
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Ayala Yáñez R, Conn PM. Protein disulfide isomerase chaperone ERP-57 decreases plasma membrane expression of the human GnRH receptor. Cell Biochem Funct 2010; 28:66-73. [PMID: 20029959 DOI: 10.1002/cbf.1622] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Retention of misfolded proteins by the endoplasmic reticulum (ER) is a quality control mechanism involving the participation of endogenous chaperones such as calnexin (CANX). CANX interacts with and restricts plasma membrane expression (PME) of the gonadotropin releasing hormone receptor (GnRHR), a G protein-coupled receptor. CANX also interacts with ERP-57 a thiol oxidoreductase chaperone present in the ER. CANX along with ERP-57 promotes the formation of disulfide bond bridges in nascent proteins. The human GnRH receptor (hGnRHR) is stabilized by two disulfide bond bridges (C(14)-C(200) and C(114)-C(196)), that, when broken, lead to a decrease in receptor expression at the plasma membrane. To determine if the presence of chaperones CANX and ERP-57 exerts an influence over membrane routing and second messenger activation, we assessed the effect of various mutants including those with broken disulfide bridges (Cys --> Ala) along with the hGnRHR. The effect of chaperones on mutants was insignificant, whereas the over expression of ERP-57 led to an hGnRHR retention. This effect was further enhanced by cotransfection with cDNA for CANX showing receptor retention by ERP-57 augmented by CANX, suggesting utilization of these chaperones for quality control of the GnRHR.
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11
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Janot M, Audfray A, Loriol C, Germot A, Maftah A, Dupuy F. Glycogenome expression dynamics during mouse C2C12 myoblast differentiation suggests a sequential reorganization of membrane glycoconjugates. BMC Genomics 2009; 10:483. [PMID: 19843320 PMCID: PMC2772862 DOI: 10.1186/1471-2164-10-483] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 10/20/2009] [Indexed: 11/10/2022] Open
Abstract
Background Several global transcriptomic and proteomic approaches have been applied in order to obtain new molecular insights on skeletal myogenesis, but none has generated any specific data on glycogenome expression, and thus on the role of glycan structures in this process, despite the involvement of glycoconjugates in various biological events including differentiation and development. In the present study, a quantitative real-time RT-PCR technology was used to profile the dynamic expression of 375 glycogenes during the differentiation of C2C12 myoblasts into myotubes. Results Of the 276 genes expressed, 95 exhibited altered mRNA expression when C2C12 cells differentiated and 37 displayed more than 4-fold up- or down-regulations. Principal Component Analysis and Hierarchical Component Analysis of the expression dynamics identified three groups of coordinately and sequentially regulated genes. The first group included 12 down-regulated genes, the second group four genes with an expression peak at 24 h of differentiation, and the last 21 up-regulated genes. These genes mainly encode cell adhesion molecules and key enzymes involved in the biosynthesis of glycosaminoglycans and glycolipids (neolactoseries, lactoseries and ganglioseries), providing a clearer indication of how the plasma membrane and extracellular matrix may be modified prior to cell fusion. In particular, an increase in the quantity of ganglioside GM3 at the cell surface of myoblasts is suggestive of its potential role during the initial steps of myogenic differentiation. Conclusion For the first time, these results provide a broad description of the expression dynamics of glycogenes during C2C12 differentiation. Among the 37 highly deregulated glycogenes, 29 had never been associated with myogenesis. Their biological functions suggest new roles for glycans in skeletal myogenesis.
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Affiliation(s)
- Mathilde Janot
- INRA, UMR 1061 Unité de Génétique Moléculaire Animale, Université de Limoges, Faculté des Sciences et Techniques, 123 Avenue A, Thomas, 87060 Limoges, France.
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12
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Kang K, Park B, Oh C, Cho K, Ahn K. A role for protein disulfide isomerase in the early folding and assembly of MHC class I molecules. Antioxid Redox Signal 2009; 11:2553-61. [PMID: 19388826 DOI: 10.1089/ars.2009.2465] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Proper folding and assembly of major histocompatibility complex (MHC) class I complexes are essential for optimal peptide loading and subsequent antigen presentation. MHC class I folding involves the coordinated formation of multiple disulfide bonds within MHC class I molecules. However, the regulation of disulfide bond formation during the early process of MHC class I folding is uncharacterized. Here, we show that protein disulfide isomerase (PDI) catalyzes the disulfide bond formation of MHC class I molecules and thereby facilitates the assembly of MHC class I heavy chain with beta(2)-microglobulin (beta(2)m). Depletion of PDI but not ERp57 by RNAi interfered with the disulfide bond formation in the MHC class I molecules. In the absence of PDI, the association of free class I heavy chain with calnexin increased, whereas the assembly of MHC class I heavy chain-beta(2)m heterodimers was delayed. These observations suggest that PDI-catalyzed disulfide bond formation of MHC class I molecules is an event downstream of the interaction of class I molecules with calnexin and upstream of their interaction with beta(2)m. Thus, our data establish a critical function for PDI in the early assembly of MHC class I molecules.
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Affiliation(s)
- Kwonyoon Kang
- National Creative Research Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul 151-747, South Korea
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13
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Effect of a tapasin mutant on the assembly of the mouse MHC class I molecule H2-K(d). Immunol Cell Biol 2009; 88:57-62. [PMID: 19687800 DOI: 10.1038/icb.2009.59] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Major histocompatibility complex (MHC) class I heavy chain/beta(2)m heterodimers assemble with antigenic peptides through interactions with peptide-loading complex proteins, including tapasin and ERp57. In human cells, a cysteine residue within tapasin (C95) has been shown to form a covalent bond with ERp57. In this study, we focused on the effect of this tapasin amino-acid residue in mouse cells expressing the MHC class I molecule H2-K(d). We showed that a large disulfide-bonded complex was present in the mouse cells that included ERp57, tapasin, and K(d). Furthermore, in mouse cells, unlike human cells, we found that tapasin mutated at C95 can participate in a non-covalent complex with ERp57. Comparison of our findings to earlier findings with a human molecule (HLA-B(*)4402) also revealed that a tapasin C95 mutation has a stronger effect on the maturation and stability of K(d) than HLA-B(*)4402. Overall, our results characterize the influence of this tapasin cysteine residue on the stable surface expression of a mouse MHC class I molecule and reveal differences in tapasin C95 interactions and effects between mouse and human systems.
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14
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Wang X, Simone LC, Tuli A, Solheim JC. Comparative analysis of the impact of a free cysteine in tapasin on the maturation and surface expression of murine MHC class I allotypes. Int J Immunogenet 2009; 36:183-7. [PMID: 19490214 DOI: 10.1111/j.1744-313x.2009.00840.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tapasin is a key molecule in the major histocompatibility complex (MHC) class I peptide-loading complex, interacting with several other proteins in the complex. An amino acid substitution at a free cysteine position in tapasin has been shown to disrupt the covalent association of tapasin with ERp57. In this study, we mutated the free cysteine in mouse tapasin, and analysed the effects on the cell surface expression of the mouse MHC class I molecules K(d) and K(b). The C95S substitution in mouse tapasin increased the proportion of open forms relative to folded forms for both types of MHC class I molecules at the cell surface. Furthermore, the C95S substitution resulted in increased association of tapasin with folded K(d). Overall, our studies with these mouse MHC class I allotypes have revealed that the free cysteine 95 in mouse tapasin influences stable expression at the plasma membrane for both MHC class I allotypes, and have shown that tapasin's interaction with folded K(d) is elevated by the C95S substitution in tapasin.
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Affiliation(s)
- X Wang
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-6805, USA
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15
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Kim Y, Kang K, Kim I, Lee YJ, Oh C, Ryoo J, Jeong E, Ahn K. Molecular mechanisms of MHC class I-antigen processing: redox considerations. Antioxid Redox Signal 2009; 11:907-36. [PMID: 19178136 DOI: 10.1089/ars.2008.2316] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Major histocompatibility complex (MHC) class I molecules present antigenic peptides to the cell surface for screening by CD8(+) T cells. A number of ER-resident chaperones assist the assembly of peptides onto MHC class I molecules, a process that can be divided into several steps. Early folding of the MHC class I heavy chain is followed by its association with beta(2)-microglobulin (beta(2)m). The MHC class I heavy chain-beta(2)m heterodimer is incorporated into the peptide-loading complex, leading to peptide loading, release of the peptide-filled MHC class I molecules from the peptide-loading complex, and exit of the complete MHC class I complex from the ER. Because proper antigen presentation is vital for normal immune responses, the assembly of MHC class I molecules requires tight regulation. Emerging evidence indicates that thiol-based redox regulation plays critical roles in MHC class I-restricted antigen processing and presentation, establishing an unexpected link between redox biology and antigen processing. We review the influences of redox regulation on antigen processing and presentation. Because redox signaling pathways are a rich source of validated drug targets, newly discovered redox biology-mediated mechanisms of antigen processing may facilitate the development of more selective and therapeutic drugs or vaccines against immune diseases.
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Affiliation(s)
- Youngkyun Kim
- National Creative Research Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, South Korea
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16
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Simone LC, Wang X, Tuli A, McIlhaney MM, Solheim JC. Influence of the tapasin C terminus on the assembly of MHC class I allotypes. Immunogenetics 2008; 61:43-54. [PMID: 18958466 DOI: 10.1007/s00251-008-0335-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 09/29/2008] [Indexed: 11/30/2022]
Abstract
Several endoplasmic reticulum proteins, including tapasin, play an important role in major histocompatibility complex (MHC) class I assembly. In this study, we assessed the influence of the tapasin cytoplasmic tail on three mouse MHC class I allotypes (H2-K(b), -K(d), and -L(d)) and demonstrated that the expression of truncated mouse tapasin in mouse cells resulted in very low K(b), K(d), and L(d) surface expression. The surface expression of K(d) also could not be rescued by human soluble tapasin, suggesting that the surface expression phenotype of the mouse MHC class I molecules in the presence of soluble tapasin was not due to mouse/human differences in tapasin. Notably, soluble mouse tapasin was able to partially rescue HLA-B8 surface expression on human 721.220 cells. Thus, the cytoplasmic tail of tapasin (either mouse or human) has a stronger impact on the surface expression of murine MHC class I molecules on mouse cells than on the expression of HLA-B8 on human cells. A K408W mutation in the mouse tapasin transmembrane/cytoplasmic domain disrupted K(d) folding and release from tapasin, but not interaction with transporter associated with antigen processing (TAP), indicating that the mechanism whereby the tapasin transmembrane/cytoplasmic domain facilitates MHC class I assembly is not limited to TAP stabilization. Our findings indicate that the C terminus of mouse tapasin plays a vital role in enabling murine MHC class I molecules to be expressed at the surface of mouse cells.
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Affiliation(s)
- Laura C Simone
- Eppley Institute for Research in Cancer and Allied Diseases and Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, USA
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17
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Feng ML, Yin B, Shen T, Huang H, Zheng JW, Qian KC, Liu DZ. Determination of TAP1 and TAP2 polymorphism in the Chinese Han population by real-time TaqMan polymerase chain reaction. TISSUE ANTIGENS 2008; 72:441-7. [PMID: 18764808 DOI: 10.1111/j.1399-0039.2008.01121.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The heterodimeric transporter associated with antigen processing (TAP) complex plays a key role in immune surveillance. TAP1 and TAP2 typing was usually performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism and PCR-sequence-specific oligonucleotide probe. As an alternative to these methods, we have established TaqMan assays to determine the frequencies of the TAP1 and TAP2 alleles. We have used these new TaqMan assays to genotype the polymorphisms in 339 unrelated Chinese Hans residing in North and South China. We detected five TAP1 and four TAP2 alleles. All the loci conform to the Hardy-Weinberg expectations. The most frequent alleles in Chinese Hans were TAP1*0101 (79.79%) and TAP2*0101 (82.74%). The two-locus haplotype analysis showed highly significant positive linkage disequilibrium for one TAP1-TAP2 haplotype (TAP1*020101-TAP2*0102), three TAP1-DRB1 haplotypes (TAP1*020101-DRB1*03, TAP1*020102-DRB1*13, and TAP1*0301-DRB1*16), and three TAP2-DRB1 haplotypes (TAP2*0102-DRB1*09, TAP2*0103-DRB1*04, and TAP2*0201-DRB1*01). The three-locus haplotype analysis showed highly significant positive linkage disequilibrium for TAP1*0101-TAP2*0101-DRB1*07, TAP1*0101-TAP2*0103-DRB1*04, TAP1*020101-TAP2*0101-DRB1*03, and TAP1*020101-TAP2*0102-DRB1*13. Comparison of the allele frequencies with those of other populations showed that the TAP1 allele distribution was very similar in all the groups, except for the Guarani, Kaingang, and Anatolian populations, but TAP2 distribution was significantly different from that of the other populations. The new TaqMan method provides relatively accurate, high-resolution, simple, and fast assays for TAP genotyping.
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Affiliation(s)
- M L Feng
- Shanghai Blood Center, Shanghai, China
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18
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Purcell AW, Elliott T. Molecular machinations of the MHC-I peptide loading complex. Curr Opin Immunol 2008; 20:75-81. [PMID: 18243674 DOI: 10.1016/j.coi.2007.12.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 12/09/2007] [Indexed: 10/22/2022]
Abstract
The acquisition of an optimal peptide ligand by MHC class I molecules is crucial for the generation of immunity to viruses and tumors. This process is orchestrated by a molecular machine known as the peptide loading complex (PLC) that consists of specialized and general ER-resident molecules. These proteins collaborate to ensure the loading of an optimal peptide ligand into the antigen binding cleft of class I molecules. The surprising diversity of peptides bound to MHC class I molecules and recapitulation of class I assembly in vitro have provided new insights into the molecular machinations of peptide loading. Coupled with the extraordinary polymorphism of class I molecules and their differential dependence on various components of the PLC for cell surface expression, a picture of peptide loading at the molecular level has recently emerged and will be discussed herein.
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Affiliation(s)
- Anthony W Purcell
- Department of Biochemistry and Molecular Biology, Bio21 Institute for Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
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19
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Belicha-Villanueva A, McEvoy S, Cycon K, Ferrone S, Gollnick SO, Bangia N. Differential contribution of TAP and tapasin to HLA class I antigen expression. Immunology 2008; 124:112-20. [PMID: 18194274 DOI: 10.1111/j.1365-2567.2007.02746.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Expression of class I human leucocyte antigens (HLA) on the surface of malignant cells is critical for their recognition and destruction by cytotoxic T lymphocytes. Surface expression requires assembly and folding of HLA class I molecules in the endoplasmic reticulum with the assistance of proteins such as Transporter associated with Antigen Processing (TAP) and tapasin. Interferon-gamma induces both TAP and tapasin so dissection of which protein contributes more to HLA class I expression has not been possible previously. In this study, we take advantage of a human melanoma cell line in which TAP can be induced, but tapasin cannot. Interferon-gamma increases TAP protein levels dramatically but HLA class I expression at the cell surface does not increase substantially, indicating that a large increase in peptide supply is not sufficient to increase HLA class I expression. On the other hand, transfection of either allelic form of tapasin (R240 or T240) enhances HLA-B*5001 and HLA-B*5701 antigen expression considerably with only a modest increase in TAP. Together, these data indicate that in the presence of minimal TAP activity, tapasin can promote substantial HLA class I expression at the cell surface.
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Affiliation(s)
- Alan Belicha-Villanueva
- Department of Immunology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
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20
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Chambers JE, Jessop CE, Bulleid NJ. Formation of a Major Histocompatibility Complex Class I Tapasin Disulfide Indicates a Change in Spatial Organization of the Peptide-loading Complex during Assembly. J Biol Chem 2008; 283:1862-9. [DOI: 10.1074/jbc.m708196200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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21
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Cabrera CM. The Double Role of the Endoplasmic Reticulum Chaperone Tapasin in Peptide Optimization of HLA Class I Molecules. Scand J Immunol 2007; 65:487-93. [PMID: 17523940 DOI: 10.1111/j.1365-3083.2007.01934.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During the assembly of the HLA class I molecules with peptides in the peptide-loading complex, a series of transient interactions are made with ER-resident chaperones. These interactions culminate in the trafficking of the HLA class I molecules to the cell surface and presentation of peptides to CD8(+) T lymphocytes. Within the peptide-loading complex, the glycoprotein tapasin exhibits a relevant function. This immunoglobulin (Ig) superfamily member in the endoplasmic reticulum membrane tethers empty HLA class I molecules to the transporter associated with antigen-processing (TAP) proteins. This review will address the current concepts regarding the double role that tapasin plays in the peptide optimization and surface expression of the HLA class I molecules.
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Affiliation(s)
- C M Cabrera
- Stem Cell Bank of Andalucia (Spanish Central Node), Hospital Universitario Virgen de las Nieves, Granada, Spain.
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22
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Selivanova A, Winblad B, Dantuma NP, Farmery MR. Biogenesis and processing of the amyloid precursor protein in the early secretory pathway. Biochem Biophys Res Commun 2007; 357:1034-9. [PMID: 17466275 DOI: 10.1016/j.bbrc.2007.04.062] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 04/08/2007] [Indexed: 10/23/2022]
Abstract
The beta-amyloid peptide is an aggregation-prone peptide that is released from the amyloid precursor protein (APP) after cleavage by the beta- and gamma-secretase. A number of studies have suggested that processing of APP by beta- and gamma-secretase occurs not only at the cell surface and in the endosomal compartments but also in the endoplasmic reticulum (ER) and Golgi complex. Here, we studied the role of the early secretory pathway in processing of APP. For this purpose, APP was in vitro translated in semi-permeabilized cells, which have a functionally intact ER and Golgi complex but lack a functional plasma membrane. We show that the beta-secretase cleavage product C99 is generated in the early secretory pathway. Moreover, nicastrin and presenilin, two components of the gamma-secretase complex, interacted with newly synthesized APP. Administration of the gamma-secretase inhibitor L685,458 caused accumulation of full length APP and C99. Full length APP but not C99 interacted with several protein quality control ER chaperones including the thiol oxidoreductase ERp57. Our in vitro study suggests that newly synthesized APP is subject to amyloidogenic processing during the initial phases of the secretory pathway.
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Affiliation(s)
- Alexandra Selivanova
- Department of Neurobiology, Caring Sciences and Society (NVS), KI Alzheimer Disease Research Center, Karolinska Institutet, Novum 5th Floor, S-141 57 Stockholm, Sweden.
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23
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Rolland AD, Evrard B, Guitton N, Lavigne R, Calvel P, Couvet M, Jégou B, Pineau C. Two-Dimensional Fluorescence Difference Gel Electrophoresis Analysis of Spermatogenesis in the Rat. J Proteome Res 2007; 6:683-97. [PMID: 17269725 DOI: 10.1021/pr060436z] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular mechanisms underlying normal and pathological spermatogenesis remain poorly understood. We compared protein concentrations in different germ cell types to identify those proteins specifically or preferentially expressed at each stage of rat spermatogenesis. Crude cytosolic protein extracts and reversed-phase HPLC prefractionated cytosolic extracts from spermatogonia, pachytene spermatocytes, and early spermatids were subjected to two-dimensional difference gel electrophoresis (2-D DIGE). By comparing gels and carrying out statistical analyses, we were able to identify 1274 protein spots with relative abundances differing significantly between the three cell types. We found that 265 of these spots displaying highly differential expression (ratio > or = 2.5 between two cell types), identified by mass fingerprinting, corresponded to 123 nonredundant proteins. The proteins clustered into three clades, corresponding to mitotic, meiotic, and post-meiotic cell types. The differentially expressed proteins identified by 2-D DIGE were confirmed and validated by western blotting and immunohistochemistry, in the few cases in which antibodies were available. 2-D DIGE appears a relevant proteomics approach for studying rat germ cell differentiation, allowing the establishment of the precise expression profiles for a relatively large number of proteins during normal spermatogenesis.
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Affiliation(s)
- Antoine D Rolland
- INSERM U625, UPRES JE 2459, IFR 140, Université Rennes I, Campus de Beaulieu, Rennes F-35042, France
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24
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Görlach A, Klappa P, Kietzmann T. The endoplasmic reticulum: folding, calcium homeostasis, signaling, and redox control. Antioxid Redox Signal 2006; 8:1391-418. [PMID: 16986999 DOI: 10.1089/ars.2006.8.1391] [Citation(s) in RCA: 493] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The endoplasmic reticulum (ER) plays a major role in regulating synthesis, folding, and orderly transport of proteins. It is also essentially involved in various cellular signaling processes, primarily by its function as a dynamic Ca(2+) store. Compared to the cytosol, oxidizing conditions are found in the ER that allow oxidation of cysteine residues in nascent polypeptide chains to form intramolecular disulfide bonds. However, compounds and enzymes such as PDI that catalyze disulfide bonds become reduced and have to be reoxidized for further catalytic cycles. A number of enzymes, among them products of the ERO1 gene, appear to provide oxidizing equivalents, and oxygen appears to be the final oxidant in aerobic living organisms. Thus, protein oxidation in the ER is connected with generation of reactive oxygen species (ROS). Changes in the redox state and the presence of ROS also affect the Ca(2+) homeostasis by modulating the functionality of ER-based channels and buffering chaperones. In addition, a close relationship exists between oxidative stress and ER stress, which both may activate signaling events leading to a rebalance of folding capacity and folding demand or to cell death. Thus, redox homeostasis appears to be a prerequisite for proper functioning of the ER.
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Affiliation(s)
- Agnes Görlach
- Experimental Pediatric Cardiology, Department of Pediatric Cardiology and Congenital Heart Disease, German Heart Center Munich at the Technical University Munich, Munich, Germany
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25
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Zhang Y, Baig E, Williams DB. Functions of ERp57 in the Folding and Assembly of Major Histocompatibility Complex Class I Molecules. J Biol Chem 2006; 281:14622-31. [PMID: 16567808 DOI: 10.1074/jbc.m512073200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ERp57 is a thiol oxidoreductase of the endoplasmic reticulum that appears to be recruited to substrates indirectly through its association with the molecular chaperones calnexin and calreticulin. However, its functions in living cells have been difficult to demonstrate. During the biogenesis of class I histocompatibility molecules, ERp57 has been detected in association with free class I heavy chains and, at a later stage, with a large complex termed the peptide loading complex. This implicates ERp57 in heavy chain disulfide formation, isomerization, or reduction as well as in the loading of peptides onto class I molecules. In this study, we show that ERp57 does indeed participate in oxidative folding of the heavy chain. Depletion of ERp57 by RNA interference delayed heavy chain disulfide bond formation, slowed folding of the heavy chain alpha(3) domain, and caused slight delays in the transport of class I molecules from the endoplasmic reticulum to the Golgi apparatus. In contrast, heavy chain-beta(2)-microglobulin association kinetics were normal, suggesting that the interaction between heavy chain and beta(2) -microglobulin does not depend on an oxidized alpha(3) domain. Likewise, the peptide loading complex assembled properly, and peptide loading appeared normal upon depletion of ERp57. These studies demonstrate that ERp57 is involved in disulfide formation in vivo but do not support a role for ERp57 in peptide loading of class I molecules. Interestingly, depletion of another thiol oxidoreductase, ERp72, had no detectable effect on class I biogenesis, consistent with a specialized role for ERp57 in this process.
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Affiliation(s)
- Yinan Zhang
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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26
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Soldà T, Garbi N, Hämmerling GJ, Molinari M. Consequences of ERp57 Deletion on Oxidative Folding of Obligate and Facultative Clients of the Calnexin Cycle. J Biol Chem 2006; 281:6219-26. [PMID: 16407314 DOI: 10.1074/jbc.m513595200] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the protein-disulfide isomerase superfamily catalyze the formation of intra- and intermolecular disulfide bonds, a rate-limiting step of protein folding in the endoplasmic reticulum (ER). Here we compared maturation of one obligate and two facultative calnexin substrates in cells with and without ERp57, the calnexin-associated, glycoprotein-specific oxidoreductase. ERp57 deletion did not prevent the formation of disulfide bonds during co-translational translocation of nascent glycopolypeptides in the ER. It affected, however, the post-translational phases of oxidative influenza virus hemagglutinin (HA) folding, resulting in significant loss of folding efficiency for this obligate calnexin substrate. Without ERp57, HA also showed reduced capacity to recover from an artificially induced aberrant conformation, thus revealing a crucial role of ERp57 during post-translational reshuffling to the native set of HA disulfides. ERp57 deletion did not affect maturation of the model facultative calnexin substrates E1 and p62 (and of most cellular proteins, as shown by lack of induction of ER stress). ERp72 was identified as one of the ER-resident oxidoreductases associating with the orphan ERp57 substrates to maintain their folding competence.
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Affiliation(s)
- Tatiana Soldà
- Institute for Research in Biomedicine, CH-6500 Bellinzona, Switzerland
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27
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Garbi N, Tanaka S, Momburg F, Hämmerling GJ. Impaired assembly of the major histocompatibility complex class I peptide-loading complex in mice deficient in the oxidoreductase ERp57. Nat Immunol 2005; 7:93-102. [PMID: 16311600 DOI: 10.1038/ni1288] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Accepted: 10/05/2005] [Indexed: 11/09/2022]
Abstract
The thiol-oxidoreductase ERp57 is an integral component of the peptide-loading complex of the major histocompatibility complex (MHC) class I pathway, but its function is unknown. To investigate its function in antigen presentation, we generated ERp57-deficient mice. Death in utero caused by ubiquitous ERp57 deletion was prevented by specific deletion in the B cell compartment. We demonstrate that ERp57 was central for recruitment of MHC class I molecules into the loading complex. In ERp57-deficient cells, we found short-lived interaction of MHC class I molecules with the loading complex. Thus, in the steady state, very few MHC class I molecules were present in the loading complex. Surface H-2K(b)-peptide expression and stability were reduced, and presentation of a model antigen was decreased. Our results indicate that ERp57 does not influence the redox state of MHC class I molecules but is an essential structural component required for stable assembly of the peptide-loading complex.
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Affiliation(s)
- Natalio Garbi
- Division of Molecular Immunology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
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28
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Garbi N, Tanaka S, van den Broek M, Momburg F, Hämmerling GJ. Accessory molecules in the assembly of major histocompatibility complex class I/peptide complexes: how essential are they for CD8+ T-cell immune responses? Immunol Rev 2005; 207:77-88. [PMID: 16181328 DOI: 10.1111/j.0105-2896.2005.00303.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Assembly of major histocompatibility complex (MHC) class I molecules in the endoplasmic reticulum is a highly coordinated process that results in abundant class I/peptide complexes at the cell surface for recognition by CD8(+) T cells and natural killer cells. During the assembly process, a number of chaperones and accessory molecules, such as transporter associated with antigen processing, tapasin, ER60, and calreticulin, assist newly synthesized class I molecules to facilitate loading of antigenic peptides and to optimize the repertoire of surface class I/peptide complexes. This review focuses on the relative importance of these accessory molecules for CD8(+) T-cell responses in vivo and discusses reasons that may help explain why some CD8(+) T-cell responses develop normally in mice deficient in components of class I assembly, despite impaired antigen presentation.
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Affiliation(s)
- Natalio Garbi
- Division of Molecular Immunology, German Cancer Research Center, Heidelberg, Germany
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29
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Ambagala APN, Solheim JC, Srikumaran S. Viral interference with MHC class I antigen presentation pathway: the battle continues. Vet Immunol Immunopathol 2005; 107:1-15. [PMID: 15978672 DOI: 10.1016/j.vetimm.2005.04.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 03/25/2005] [Accepted: 04/06/2005] [Indexed: 01/15/2023]
Abstract
CD8+ cytotoxic T lymphocytes (CTLs) play a critical role in the defense against viral infections. In general, CD8+ CTLs recognize antigenic peptides in the context of the major histocompatibility complex (MHC) class I molecule. The MHC class I molecules are expressed on almost all the nucleated cells in the body. The trimolecular complex consisting of the class I heavy chain, beta2-microglobulin and the peptide are generated by the MHC class I antigen presentation pathway. This pathway is designed to sample the intracellular milieu and present the information to the CTLs trafficking the area. This rigorous sampling of intracellular environment enables the CTLs to quickly identify and eliminate the cells that synthesize non-self proteins as a result of a viral infection. Many viruses, including several viruses of veterinary importance, have evolved astounding strategies to interfere with the MHC class I antigen presentation pathway, as a means of evading the CTL response of the host. This review focuses on the diverse mechanisms of viral evasion of the MHC class I antigen presentation pathway with particular emphasis on viruses of veterinary importance.
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Affiliation(s)
- Aruna P N Ambagala
- Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, NE 68583-0905, USA
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30
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York IA, Grant EP, Dahl AM, Rock KL. A mutant cell with a novel defect in MHC class I quality control. THE JOURNAL OF IMMUNOLOGY 2005; 174:6839-46. [PMID: 15905525 DOI: 10.4049/jimmunol.174.11.6839] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
COS7 (African Green Monkey kidney) cells stably transfected with the mouse MHC class I allele H-2K(b) were mutagenized, selected for low surface expression of endogenous MHC class I products, and subcloned. A mutant cell line, 4S8.12, expressing very low surface MHC class I (approximately 5% of parental levels) was identified. This cell line synthesized normal levels of the MHC class I H chain and beta(2)-microglobulin, as well as normal levels of TAP, tapasin, GRP78, calnexin, calreticulin, ERp57, and protein disulfide isomerase. Full-length OVA was processed to generate presented H-2K(b)-SIINFEKL complexes with equal efficiency in wild-type and mutant cells, demonstrating that proteasomes, as well as TAP and tapasin, functioned normally. Therefore, all the known components of the MHC class I Ag presentation pathway were intact. Nevertheless, primate (human and monkey) MHC class I H chain and beta(2)-microglobulin failed to associate to form the normal peptide-receptive complex. In contrast, mouse H chains associated with beta(2)-microglobulin normally and bound peptide at least as well as in wild-type cells. The 4S8.12 cells provide strong genetic evidence for a novel component in the MHC class I pathway. This as-yet unidentified gene is important in early assembly of primate, but not mouse, MHC class I complexes.
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Affiliation(s)
- Ian A York
- Department of Pathology, University of Massachusetts Medical Center, Worcester, 01655, USA.
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31
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Tourdot S, Nejmeddine M, Powis SJ, Gould KG. Different MHC class I heavy chains compete with each other for folding independently of beta 2-microglobulin and peptide. THE JOURNAL OF IMMUNOLOGY 2005; 174:925-33. [PMID: 15634915 DOI: 10.4049/jimmunol.174.2.925] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We reported previously that different MHC class I molecules can compete with each other for cell surface expression in F(1) hybrid and MHC class I transgenic mice. In this study, we show that the competition also occurs in transfected cell lines, and investigate the mechanism. Cell surface expression of an endogenous class I molecule in Chinese hamster ovary (CHO) cells was strongly down-regulated when the mouse K(d) class I H chain was introduced by transfection. The competition occurred only after K(d) protein translation, not at the level of RNA, and localization studies of a CHO class I-GFP fusion showed that the presence of K(d) caused retention of the hamster class I molecule in the endoplasmic reticulum. The competition was not for beta(2)-microglobulin, because a single chain version of K(d) that included mouse beta(2)-microglobulin also had a similar effect. The competition was not for association with TAP and loading with peptide, because a mutant form of the K(d) class I H chain, not able to associate with TAP, caused the same down-regulation of hamster class I expression. Moreover, K(d) expression led to a similar level of competition in TAP2-negative CHO cells. Competition for cell surface expression was also found between different mouse class I H chains in transfected mouse cells, and this competition prevented association of the H chain with beta(2)-microglobulin. These unexpected new findings show that different class I H chains compete with each other at an early stage of the intracellular assembly pathway, independently of beta(2)-microglobulin and peptide.
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Affiliation(s)
- Sophie Tourdot
- Department of Immunology, Wright-Fleming Institute, Imperial College London, London, United Kingdom
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32
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Wright CA, Kozik P, Zacharias M, Springer S. Tapasin and other chaperones: models of the MHC class I loading complex. Biol Chem 2005; 385:763-78. [PMID: 15493870 DOI: 10.1515/bc.2004.100] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
MHC (major histocompatibility complex) class I molecules bind intracellular virus-derived peptides in the endoplasmic reticulum (ER) and present them at the cell surface to cytotoxic T lymphocytes. Peptide-free class I molecules at the cell surface, however, could lead to aberrant T cell killing. Therefore, cells ensure that class I molecules bind high-affinity ligand peptides in the ER, and restrict the export of empty class I molecules to the Golgi apparatus. For both of these safeguard mechanisms, the MHC class I loading complex (which consists of the peptide transporter TAP, the chaperones tapasin and calreticulin, and the protein disulfide isomerase ERp57) plays a central role. This article reviews the actions of accessory proteins in the biogenesis of class I molecules, specifically the functions of the loading complex in high-affinity peptide binding and localization of class I molecules, and the known connections between these two regulatory mechanisms. It introduces new models for the mode of action of tapasin, the role of the class I loading complex in peptide editing, and the intracellular localization of class I molecules.
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Affiliation(s)
- Cynthia Anne Wright
- Biochemistry and Cell Biology, International University Bremen, D-28759 Bremen, Germany
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33
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Petersen JL, Hickman-Miller HD, McIlhaney MM, Vargas SE, Purcell AW, Hildebrand WH, Solheim JC. A Charged Amino Acid Residue in the Transmembrane/Cytoplasmic Region of Tapasin Influences MHC Class I Assembly and Maturation. THE JOURNAL OF IMMUNOLOGY 2005; 174:962-9. [PMID: 15634919 DOI: 10.4049/jimmunol.174.2.962] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Tapasin influences the quantity and quality of MHC/peptide complexes at the cell surface; however, little is understood about the structural features that underlie its effects. Because tapasin, MHC class I, and TAP are transmembrane proteins, the tapasin transmembrane/cytoplasmic region has the potential to affect interactions at the endoplasmic reticulum membrane. In this study, we have assessed the influence of a conserved lysine at position 408, which lies in the tapasin transmembrane/cytoplasmic domain. We found that substitutions at position K408 in tapasin affected the expression of MHC class I molecules at the cell surface, and down-regulated tapasin stabilization of TAP. In addition to affecting TAP interaction with tapasin, the substitution of alanine, but not tryptophan, for the lysine at tapasin position 408 increased the amount of tapasin found in association with the open, peptide-free form of the HLA-B8 H chain. Tapasin K408A was also associated with more folded, beta(2)-microglobulin-assembled HLA-B8 molecules than wild-type tapasin. Consistent with our observation of a large pool of tapasin K408A-associated HLA-B8 molecules, the rate at which HLA-B8 migrated from the endoplasmic reticulum was slower in tapasin K408A-expressing cells than in wild-type tapasin-expressing cells. Thus, the alanine substitution at position 408 in tapasin may interfere with the stable acquisition by MHC class I molecules of peptides that are sufficiently optimal to allow MHC class I release from tapasin.
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Affiliation(s)
- Jason L Petersen
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198, USA
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34
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Culina S, Lauvau G, Gubler B, van Endert PM. Calreticulin Promotes Folding of Functional Human Leukocyte Antigen Class I Molecules in Vitro. J Biol Chem 2004; 279:54210-5. [PMID: 15494401 DOI: 10.1074/jbc.m410841200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The assembly of MHC class I molecules with beta(2)-microglobulin and peptides is assisted by the housekeeping chaperones calnexin, calreticulin, and Erp57 and the dedicated accessory protein, tapasin. Tapasin and calreticulin are essential for efficient MHC class I assembly, but their precise action during class I assembly remains to be elucidated. Previous in vitro studies have demonstrated that the lectin calreticulin interacts with monoglucosylated MHC class I heavy chains, whatever their state of assembly with light chains and peptide, and inhibits their aggregation above physiological temperature. We used a soluble single chain HLA-A2/beta(2)-microglobulin molecule, A2SC, to study the effect of calreticulin on the peptide binding capacity of HLA class I molecules. Calreticulin inhibited the formation of A2SC aggregates both when co-expressed in insect cells and during incubations at elevated temperature. Calreticulin dramatically enhanced acquisition of peptide binding capacity when added to denatured A2SC molecules during refolding at 4 degrees C. However, it had no effect on the rapid loss of A2SC peptide binding capacity at physiological temperature. We conclude that calreticulin promotes the folding of HLA class I molecules to a state in which, at low temperature, they spontaneously acquire peptide binding capacity. However, it does not induce or maintain a peptide-receptive state of the class I-binding site, which is likely to be promoted by one or several other components of the class I loading complexes. By being amenable to complementation with additional proteins, the described system should be useful for identification of these components.
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Affiliation(s)
- Slobodan Culina
- Institut National de la Santé et de la Recherche Médicale Unité 580, Université René Descartes Paris V, 75015 Paris, France
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35
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Silvennoinen L, Myllyharju J, Ruoppolo M, Orrù S, Caterino M, Kivirikko KI, Koivunen P. Identification and Characterization of Structural Domains of Human ERp57. J Biol Chem 2004; 279:13607-15. [PMID: 14732712 DOI: 10.1074/jbc.m313054200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amino acid sequence of ERp57, which functions in the endoplasmic reticulum together with the lectins calreticulin and calnexin to achieve folding of newly synthesized glycoproteins, is highly similar to that of protein disulfide isomerase (PDI), but they have their own distinct roles in protein folding. We have characterized the domain structure of ERp57 by limited proteolysis and N-terminal sequencing and have found it to be similar but not identical to that of PDI. ERp57 had three major protease-sensitive regions, the first of which was located between residues 120 and 150, the second between 201 and 215, and the third between 313 and 341, the data thus being consistent with a four-domain structure abb'a'. Recombinant expression in Escherichia coli was used to verify the domain boundaries. Each single domain and a b'a' double domain could be produced in the form of soluble, folded polypeptides, as verified by circular dichroism spectra and urea gradient gel electrophoresis. When the ability of ERp57 and its a and a' domains to fold denatured RNase A was studied by electrospray mass analyses, ERp57 markedly enhanced the folding rate at early time points, although less effectively than PDI, but was an ineffective catalyst of the overall process. The a and a' domains produced only minor, if any, increases in the folding rate at the early stages and no increase at the late stages. Interaction of the soluble ERp57 domains with the P domain of calreticulin was studied by chemical cross-linking in vitro. None of the single ERp57 domains nor the b'a' double domain could be cross-linked to the P domain, whereas cross-linking was obtained with a hybrid ERpabb'PDIa'c polypeptide but not with ERpabPDIb'a'c, indicating that multiple domains are involved in this protein-protein interaction and that the b' domain of ERp57 cannot be replaced by that of PDI.
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Affiliation(s)
- Laura Silvennoinen
- Department of Medical Biochemistry and Molecular Biology, University of Oulu, PO Box 5000, FIN-90014 Oulu, Finland
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36
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Albring J, Koopmann JO, Hämmerling GJ, Momburg F. Retrotranslocation of MHC class I heavy chain from the endoplasmic reticulum to the cytosol is dependent on ATP supply to the ER lumen. Mol Immunol 2004; 40:733-41. [PMID: 14644099 DOI: 10.1016/j.molimm.2003.08.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
MHC class I heavy chains (HC) that fail to acquire a mature conformation in the endoplasmic reticulum (ER) as a result of defective folding or assembly with beta2-microglobulin, or lack of appropriate peptide cargo are retrotranslocated through the Sec61 channel to the cytosol for degradation by proteasomes. The mechanisms involved in ER retrotranslocation of HC are as yet incompletely understood. Using a microsomal system, we characterized the molecular requirements for the release of HC into the soluble fraction. Extraction of ubiquitinated HC was facilitated by cytosol, or by addition of proteins that stabilized the membrane association of the cytoplasmic ATPase p97. Functional proteasomes were not needed for HC mobilization. ATP supply to the ER lumen was found to be an essential factor since an inhibitor of the ATP importing pump in the ER membrane blocked HC release. Also non-hydrolyzable ATP analogs delivered to the ER lumen facilitated HC export suggesting that ATP binding by ER chaperones rather than ATP hydrolysis is involved.
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Affiliation(s)
- Jörn Albring
- Division of Molecular Immunology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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37
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Frenkel Z, Shenkman M, Kondratyev M, Lederkremer GZ. Separate roles and different routing of calnexin and ERp57 in endoplasmic reticulum quality control revealed by interactions with asialoglycoprotein receptor chains. Mol Biol Cell 2004; 15:2133-42. [PMID: 14978212 PMCID: PMC404010 DOI: 10.1091/mbc.e03-12-0899] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The thiol oxidoreductase endoplasmic reticulum (ER)p57 interacts with newly synthesized glycoproteins through ternary complexes with the chaperones/lectins calnexin or calreticulin. On proteasomal inhibition calnexin and calreticulin concentrate in the pericentriolar endoplasmic reticulum-derived quality control compartment that we recently described. Surprisingly, ERp57 remained in an endoplasmic reticulum pattern. Using asialoglycoprotein receptor H2a and H2b as models, we determined in pulse-chase experiments that both glycoproteins initially bind to calnexin and ERp57. However, H2b, which will exit to the Golgi, dissociated from calnexin and remained bound for a longer period to ERp57, whereas the opposite was true for the endoplasmic reticulum-associated degradation substrate H2a that will go to the endoplasmic reticulum-derived quality control compartment. At 15 degrees C, ERp57 colocalized with H2b adjacent to an endoplasmic reticulum-Golgi intermediate compartment marker. Posttranslational inhibition of glucose excision prolonged association of H2a precursor to calnexin but not to ERp57. Preincubation with a low concentration (15 microg/ml) of the glucosidase inhibitor castanospermine prevented the association of H2a to ERp57 but not to calnexin. This low concentration of castanospermine accelerated the degradation of H2a, suggesting that ERp57 protects the glycoprotein from degradation and not calnexin. Our results suggest an early chaperone-mediated sorting event with calnexin being involved in the quality control retention of molecules bound for endoplasmic reticulum-associated degradation and ERp57 giving initial protection from degradation and later assisting the maturation of molecules that will exit to the Golgi.
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Affiliation(s)
- Zehavit Frenkel
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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38
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Purcell AW, Gorman JJ. Immunoproteomics: Mass spectrometry-based methods to study the targets of the immune response. Mol Cell Proteomics 2004; 3:193-208. [PMID: 14718575 DOI: 10.1074/mcp.r300013-mcp200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mammalian immune system has evolved to display fragments of protein antigens derived from microbial pathogens to immune effector cells. These fragments are typically peptides liberated from the intact antigens through distinct proteolytic mechanisms that are subsequently transported to the cell surface bound to chaperone-like receptors known as major histocompatibility complex (MHC) molecules. These complexes are then scrutinized by effector T cells that express clonally distributed T cell receptors with specificity for specific MHC-peptide complexes. In normal uninfected cells, this process of antigen processing and presentation occurs continuously, with the resultant array of self-antigen-derived peptides displayed on the surface of these cells. Changes in this peptide landscape of cells act to alert immune effector cells to changes in the intracellular environment that may be associated with infection, malignant transformation, or other abnormal cellular processes, resulting in a cascade of events that result in their elimination. Because peptides play such a crucial role in informing the immune system of infection with viral or microbial pathogens and the transformation of cells in malignancy, the tools of proteomics, in particular mass spectrometry, are ideally suited to study these immune responses at a molecular level. Here we review recent advances in the studies of immune responses that have utilized mass spectrometry and associated technologies, with specific examples from collaboration between our laboratories.
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Affiliation(s)
- A W Purcell
- Department of Microbiology and Immunology and ImmunoID, The University of Melbourne, Victoria 3010, Australia.
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39
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Antoniou AN, Powis SJ. Characterization of the ERp57-Tapasin complex by rapid cellular acidification and thiol modification. Antioxid Redox Signal 2003; 5:375-9. [PMID: 13678524 DOI: 10.1089/152308603768295104] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Major histocompatibility complex (MHC) class I molecules bind and present short peptides to cells of the immune system. The oxidoreductase ERp57 is involved in the assembly of MHC class I molecules and is a component of the peptide loading complex, where it is found disulfide-bonded to tapasin. We have studied ERp57 and the ERp57-tapasin conjugate by rapid acidification of the intracellular environment with trichloroacetic acid (TCA), followed by thiol modification with the alkylating agent 4'-maleimidylstilbene-2,2'-disulfonic acid (AMS). By using TCA/AMS treatment, non-tapasin-associated ERp57 is shown to exist almost exclusively in a reduced state, suggesting that both thioredoxin-like CXXC motifs are exposed and reduced. A 110-kDa product is readily detected with this TCA/AMS protocol and is confirmed as an ERp57-tapasin conjugate by its absence from the tapasin-deficient .220 cell line and by immunoblotting with both ERp57- and tapasin-specific antisera. The ERp57-tapasin conjugate can also be modified with the oxidizing agent diamide, indicating that within the pool of ERp57-tapasin complexes the free, non-tapasin-linked CXXC motif exists in both oxidized and reduced states, suggesting availability to undergo redox reactions.
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Affiliation(s)
- Antony N Antoniou
- Division of Cell Biology and Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
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40
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Paulsson K, Wang P. Chaperones and folding of MHC class I molecules in the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1641:1-12. [PMID: 12788224 DOI: 10.1016/s0167-4889(03)00048-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In this review we discuss the influence of chaperones on the general phenomena of folding as well as on the specific folding of an individual protein, MHC class I. MHC class I maturation is a highly sophisticated process in which the folding machinery of the endoplasmic reticulum (ER) is heavily involved. Understanding the MHC class I maturation per se is important since peptides loaded onto MHC class I molecules are the base for antigen presentation generating immune responses against virus, intracellular bacteria as well as tumours. This review discusses the early stages of MHC class I maturation regarding BiP and calnexin association, and differences in MHC class I heavy chain (HC) interaction with calnexin and calreticulin are highlighted. Late stage MHC class I maturation with focus on the dedicated chaperone tapasin is also discussed.
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Affiliation(s)
- Kajsa Paulsson
- The Institution of Tumour Immunology, Lund University, BMC I12, S-223 62, Lund, Sweden.
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41
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Purcell AW, Zeng W, Mifsud NA, Ely LK, Macdonald WA, Jackson DC. Dissecting the role of peptides in the immune response: theory, practice and the application to vaccine design. J Pept Sci 2003; 9:255-81. [PMID: 12803494 DOI: 10.1002/psc.456] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Analytical biochemistry and synthetic peptide based chemistry have helped to reveal the pivotal role that peptides play in determining the specificity, magnitude and quality of both humoral (antibody) and cellular (cytotoxic and helper T cell) immune responses. In addition, peptide based technologies are now at the forefront of vaccine design and medical diagnostics. The chemical technologies used to assemble peptides into immunogenic structures have made great strides over the past decade and assembly of highly pure peptides which can be incorporated into high molecular weight species, multimeric and even branched structures together with non-peptidic material is now routine. These structures have a wide range of applications in designer vaccines and diagnostic reagents. Thus the tools of the peptide chemist are exquisitely placed to answer questions about immune recognition and along the way to provide us with new and improved vaccines and diagnostics.
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Affiliation(s)
- Anthony W Purcell
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia.
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42
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Affiliation(s)
- Antony N Antoniou
- Division of Cell Biology and Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.
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43
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Radcliffe CM, Diedrich G, Harvey DJ, Dwek RA, Cresswell P, Rudd PM. Identification of specific glycoforms of major histocompatibility complex class I heavy chains suggests that class I peptide loading is an adaptation of the quality control pathway involving calreticulin and ERp57. J Biol Chem 2002; 277:46415-23. [PMID: 12235131 DOI: 10.1074/jbc.m202466200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycosylation analysis was used to probe the sequence of events accompanying the binding of antigenic peptides to the major histocompatibility complex class I heavy chains. Free heavy chains were isolated from the beta(2)-microglobulin-negative cell line Daudi and from the B-lymphoblastoid cell line Raji. Heavy chains were also isolated from Raji cells in multimolecular complexes (peptide loading complexes) containing the transporter associated with antigen processing, tapasin and ERp57 with and without the lectin-like folding chaperone, calreticulin. Calreticulin is a soluble protein that recognizes primarily the terminal glucose of Glc(1)Man(7-9)GlcNAc(2) glycans. This paper shows that monoglucosylated glycoforms of heavy chain, which exist transiently in the endoplasmic reticulum in the initial stages of the glycosylation processing pathway, are present in the peptide loading complex. The data are consistent with a model in which the release of peptide-loaded major histocompatibility complex class I molecules from calreticulin, induced by deglucosylation of the heavy chain N-linked glycan, signals the dissociation of the complex. This is consistent with the hypothesis that the class I loading process is an adaptation of the quality control mechanism involving calreticulin and ERp57.
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Affiliation(s)
- Catherine M Radcliffe
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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44
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Momburg F, Tan P. Tapasin-the keystone of the loading complex optimizing peptide binding by MHC class I molecules in the endoplasmic reticulum. Mol Immunol 2002; 39:217-33. [PMID: 12200052 DOI: 10.1016/s0161-5890(02)00103-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
MHC class I molecules are loaded with peptides that mostly originate from the degradation of cytosolic protein antigens and that are translocated across the endoplasmic reticulum (ER) membrane by the transporter associated with antigen processing (TAP). The ER-resident molecule tapasin (Tpn) is uniquely dedicated to tether class I molecules jointly with the chaperone calreticulin (Crt) and the oxidoreductase ERp57 to TAP. As learned from the study of a Tpn-deficient cell line and from mice harboring a disrupted Tpn gene, the transient association of class I molecules with Tpn and TAP is critically important for the stabilization of class I molecules and the optimization of the peptide cargo presented to cytotoxic T cells. The different functions of molecular domains of Tpn and the highly coordinated formation of the TAP-associated peptide loading complex will also be discussed in this review.
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Affiliation(s)
- F Momburg
- Department of Molecular Immunology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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45
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Trombetta ES, Parodi AJ. N-glycan processing and glycoprotein folding. ADVANCES IN PROTEIN CHEMISTRY 2002; 59:303-44. [PMID: 11868276 DOI: 10.1016/s0065-3233(01)59010-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- E S Trombetta
- Instituto de Investigaciones Biotecnológicas, Universidad de San Martín, (1650) San Martin, Pcia. de Buenos Aires, Argentina
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46
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Dangoria NS, DeLay ML, Kingsbury DJ, Mear JP, Uchanska-Ziegler B, Ziegler A, Colbert RA. HLA-B27 misfolding is associated with aberrant intermolecular disulfide bond formation (dimerization) in the endoplasmic reticulum. J Biol Chem 2002; 277:23459-68. [PMID: 11978783 DOI: 10.1074/jbc.m110336200] [Citation(s) in RCA: 192] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The class I protein HLA-B27 confers susceptibility to inflammatory arthritis in humans and when overexpressed in rodents for reasons that remain unclear. We demonstrated previously that HLA-B27 heavy chains (HC) undergo endoplasmic reticulum (ER)-associated degradation. We report here that HLA-B27 HC also forms two types of aberrant disulfide-linked complexes (dimers) during the folding and assembly process that can be distinguished by conformation-sensitive antibodies W6/32 and HC10. HC10-reactive dimers form immediately after HC synthesis in the ER and constitute at least 25% of the HC pool, whereas W6/32-reactive dimers appear several hours later and represent less than 10% of the folded HC. HC10-reactive dimers accumulate in the absence of tapasin or beta(2)-microglobulin, whereas W6/32-reactive dimers are not detected. Efficient formation of W6/32-reactive dimers appears to depend on the transporter associated with antigen processing, tapasin, and beta(2)-microglobulin. The unpaired Cys(67) and residues at the base of the B pocket that dramatically impair HLA-B27 HC folding are critical for the formation of HC10-reactive ER dimers. Although certain other alleles also form dimers late in the assembly pathway, ER dimerization of HLA-B27 may be unique. These results demonstrate that residues comprising the HLA-B27 B pocket result in aberrant HC folding and disulfide bond formation, and thus confer unusual properties on this molecule that are unrelated to peptide selection per se, yet may be important in disease pathogenesis.
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Affiliation(s)
- Nandita S Dangoria
- William S. Rowe Division of Rheumatology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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47
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Antoniou AN, Ford S, Alphey M, Osborne A, Elliott T, Powis SJ. The oxidoreductase ERp57 efficiently reduces partially folded in preference to fully folded MHC class I molecules. EMBO J 2002; 21:2655-63. [PMID: 12032078 PMCID: PMC126025 DOI: 10.1093/emboj/21.11.2655] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The oxidoreductase ERp57 is an integral component of the peptide loading complex of major histocompatibility complex (MHC) class I molecules, formed during their chaperone-assisted assembly in the endoplasmic reticulum. Misfolded MHC class I molecules or those denied suitable peptides are retrotranslocated and degraded in the cytosol. The presence of ERp57 during class I assembly suggests it may be involved in the reduction of intrachain disulfides prior to retrotranslocation. We have studied the ability of ERp57 to reduce MHC class I molecules in vitro. Recombinant ERp57 specifically reduced partially folded MHC class I molecules, whereas it had little or no effect on folded and peptide-loaded MHC class I molecules. Reductase activity was associated with cysteines at positions 56 and 405 of ERp57, the N-terminal residues of the active CXXC motifs. Our data suggest that the reductase activity of ERp57 may be involved during the unfolding of MHC class I molecules, leading to targeting for degradation.
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Affiliation(s)
| | | | | | | | - Tim Elliott
- Division of Cell Biology and Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH and
Cancer Sciences Division, University of Southampton School of Medicine, Southampton General Hospital, Southampton SO16 6YD, UK Corresponding author e-mail:
| | - Simon J. Powis
- Division of Cell Biology and Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH and
Cancer Sciences Division, University of Southampton School of Medicine, Southampton General Hospital, Southampton SO16 6YD, UK Corresponding author e-mail:
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48
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Tan P, Kropshofer H, Mandelboim O, Bulbuc N, Hämmerling GJ, Momburg F. Recruitment of MHC class I molecules by tapasin into the transporter associated with antigen processing-associated complex is essential for optimal peptide loading. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:1950-60. [PMID: 11823531 DOI: 10.4049/jimmunol.168.4.1950] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The ER protein tapasin (Tpn) forms a bridge between MHC class I H chain (HC)/beta(2)-microglobulin and the TAP peptide transporter. The function of this TAP-associated complex was unclear because it was reported that soluble Tpn that has lost TAP interaction would be fully competent in terms of peptide loading and Ag presentation. We found, however, that only wild-type human Tpn (hTpn), but not three soluble hTpn variants, a transmembrane domain point mutant of hTpn (L410-->F), wild-type mouse Tpn, nor a mouse-human Tpn hybrid, fully up-regulated peptide-dependent Bw4 epitopes when expressed in Tpn-deficient.220.B*4402 cells. Consistent with suboptimal peptide loading, the t(1/2) of class I molecules was considerably reduced in the presence of soluble hTpn, hTpn-L410F, and murine Tpn. Furthermore, eluted peptide spectra and the class I-mediated inhibition of NK clones showed distinct differences to the hTpn transfectant. Only wild-type hTpn efficiently recruited HC and calreticulin (Crt) into complexes with TAP and endoplasmic reticulum p57 (ERp57). The L410F mutant was defective in TAP association, but bound to class I molecules, Crt, and ERp57. Mouse Tpn associated with human TAP and ERp57 on the one hand, and with HC and Crt on the other, but failed to recruit normal amounts of HLA class I molecules into the TAP complex. We conclude that the loading with peptides conferring high stability requires the Tpn-mediated introduction of HC into the TAP complex, whereas the mere interaction with Tpn is not sufficient.
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Affiliation(s)
- Pamela Tan
- Department of Molecular Immunology, German Cancer Research Center (Deutsches Krebsforschungszentrum), Heidelberg, Germany
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49
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Gao B, Adhikari R, Howarth M, Nakamura K, Gold MC, Hill AB, Knee R, Michalak M, Elliott T. Assembly and antigen-presenting function of MHC class I molecules in cells lacking the ER chaperone calreticulin. Immunity 2002; 16:99-109. [PMID: 11825569 DOI: 10.1016/s1074-7613(01)00260-6] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
MHC class I molecules expressed in a calreticulin-deficient cell line (K42) assembled with beta 2-microglobulin (beta2-m) normally, but their subsequent loading with optimal peptides was defective. Suboptimally loaded class I molecules were released into the secretory pathway. This occurred despite the ability of newly synthesized class I to interact with the transporter associated with antigen processing (TAP) loading complex. The efficiency of peptide loading was reduced by 50%-80%, and impaired T cell recognition was observed for three out of four antigens tested. The peptide-loading function was specific to calreticulin, since the defect in K42 could be rectified by transfection with calreticulin but not a soluble form of calnexin, which shares its lectin-like activity.
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Affiliation(s)
- Bin Gao
- University of Oxford, Nuffield Department of Clinical Medicine, Institute for Molecular Medicine, John Radcliffe Hospital, OX3 9DS, Oxford, United Kingdom
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Dick TP, Bangia N, Peaper DR, Cresswell P. Disulfide bond isomerization and the assembly of MHC class I-peptide complexes. Immunity 2002; 16:87-98. [PMID: 11825568 DOI: 10.1016/s1074-7613(02)00263-7] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The presence of a disulfide bond inside the peptide binding groove of MHC class I molecules and of the thiol oxidoreductase ERp57 in the class I loading complex suggests that disulfide bond isomerization may play a role in peptide loading. Here we show that ERp57 and tapasin are disulfide linked inside the loading complex. Mutagenesis of cysteine 95 in tapasin not only abolishes formation of the ERp57-tapasin bond but also prevents complete oxidation of the class I heavy chain in the loading complex. The resulting MHC class I-beta2m heterodimers are poorly loaded with high-affinity peptides in the ER but nevertheless escape to the cell surface where they are unstable. These findings suggest a role for disulfide bond isomerization in tapasin-mediated peptide loading.
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Affiliation(s)
- Tobias P Dick
- Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, 310 Cedar Street, New Haven, CT 06520, USA
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