1
|
Jiang J, Natarajan K, Margulies DH. Chaperone-mediated MHC-I peptide exchange in antigen presentation. IUCRJ 2024; 11:287-298. [PMID: 38656309 PMCID: PMC11067752 DOI: 10.1107/s2052252524002768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024]
Abstract
This work focuses on molecules that are encoded by the major histocompatibility complex (MHC) and that bind self-, foreign- or tumor-derived peptides and display these at the cell surface for recognition by receptors on T lymphocytes (T cell receptors, TCR) and natural killer (NK) cells. The past few decades have accumulated a vast knowledge base of the structures of MHC molecules and the complexes of MHC/TCR with specificity for many different peptides. In recent years, the structures of MHC-I molecules complexed with chaperones that assist in peptide loading have been revealed by X-ray crystallography and cryogenic electron microscopy. These structures have been further studied using mutagenesis, molecular dynamics and NMR approaches. This review summarizes the current structures and dynamic principles that govern peptide exchange as these relate to the process of antigen presentation.
Collapse
Affiliation(s)
- Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - David H. Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| |
Collapse
|
2
|
Jia Z, Yu W, Li J, Zhang M, Zhan B, Yan L, Ming Z, Cheng Y, Tian X, Shao S, Huang J, Zhu X. Crystal structure of Trichinella spiralis calreticulin and the structural basis of its complement evasion mechanism involving C1q. Front Immunol 2024; 15:1404752. [PMID: 38690267 PMCID: PMC11059001 DOI: 10.3389/fimmu.2024.1404752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 05/02/2024] Open
Abstract
Helminths produce calreticulin (CRT) to immunomodulate the host immune system as a survival strategy. However, the structure of helminth-derived CRT and the structural basis of the immune evasion process remains unclarified. Previous study found that the tissue-dwelling helminth Trichinella spiralis produces calreticulin (TsCRT), which binds C1q to inhibit activation of the complement classical pathway. Here, we used x-ray crystallography to resolve the structure of truncated TsCRT (TsCRTΔ), the first structure of helminth-derived CRT. TsCRTΔ was observed to share the same binding region on C1q with IgG based on the structure and molecular docking, which explains the inhibitory effect of TsCRT on C1q-IgG-initiated classical complement activation. Based on the key residues in TsCRTΔ involved in the binding activity to C1q, a 24 amino acid peptide called PTsCRT was constructed that displayed strong C1q-binding activity and inhibited C1q-IgG-initiated classical complement activation. This study is the first to elucidate the structural basis of the role of TsCRT in immune evasion, providing an approach to develop helminth-derived bifunctional peptides as vaccine target to prevent parasite infections or as a therapeutic agent to treat complement-related autoimmune diseases.
Collapse
Affiliation(s)
- Zhihui Jia
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wen Yu
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Jingmo Li
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Mingming Zhang
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Bin Zhan
- Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Liming Yan
- Ministry of Education Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Zhenhua Ming
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yuli Cheng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xiaolin Tian
- Ministry of Education Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shuai Shao
- Beijing institute of Clinical Medicine, Capital Medical University Affiliated Beijing Friendship Hospital, Beijing, China
| | - Jingjing Huang
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xinping Zhu
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| |
Collapse
|
3
|
Yu F, Liu X, Li M, Liu X, Wang X, Guo M. Protein disulfide isomerase A3 as novel biomarker for endometrial cancer. Front Oncol 2023; 13:1247446. [PMID: 37909009 PMCID: PMC10614013 DOI: 10.3389/fonc.2023.1247446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/28/2023] [Indexed: 11/02/2023] Open
Abstract
Objective This study aims to investigate the potential of PDIA3 as a novel prognostic biomarker and therapeutic target for Endometrial Cancer (EC) with the ultimate goal of improving survival rates in EC patients. Methods This study employed a combination of public database analysis and clinical tissue sample assays. The analysis included comparing the gene expression of PDIA3 between EC and adjacent paracancerous tissues, investigating this expression status using qPCR and immunohistochemistry (IHC) assays, studying the correlation of expression with different parameters using Chi-square test, Cox Regression, and log-rank test, as well as exploring the PDIA3-related immune infiltration and metabolic pathway using TIMER and GSEA. Results The analysis of public datasets revealed that PDIA3 mRNA and protein expression was significantly higher in EC tissues compared to adjacent tissues (P = 4.1e-03, P = 1.95e-14, and P = 1.6e-27, respectively). The qPCR analysis supported this finding (P = 0.029). IHC analysis revealed a significant increase in PDIA3 expression in endometrial cancer (EC) tissues compared to adjacent normal tissues (P = 0.01). Furthermore, PDIA3 expression showed significant correlations with cancer stage and tumor grade. Multivariate Cox regression analysis suggested that the PDIA3 gene holds promise as a prognostic factor for EC patients (HR = 0.47, 95% CI [0.27, 0.82], P = 0.008). The results from TIMER demonstrated a positive correlation between PDIA3 and tumor-infiltrating CD8 T cells and macrophages, and a negative correlation with tumor-infiltrating CD4 T cells. Additionally, the GSEA results indicated that PDIA3 overexpression was associated with various metabolic processes in EC patients. Conclusion PDIA3 has been validated as a potential biomarker for EC, and its expression is further associated with pathological staging and prognosis.
Collapse
Affiliation(s)
- Fanrong Yu
- Department of Obstetrics and Gynecology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, China
| | - Xin Liu
- Department of Pathology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, China
| | - Min Li
- Department of Pathology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, China
| | - Xiufen Liu
- Department of Pathology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, China
| | - Xintai Wang
- School of Information Science and Technology, Dalian Maritime University, Dalian, China
- 2D Material Lab, Zhejiang Mashang Technology Research Institute, Cangnan, Wenzhou, Zhejiang, China
| | - Meixiang Guo
- Department of General Practice, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, China
| |
Collapse
|
4
|
Yusuf M, Destiarani W, Widayat W, Yosua Y, Gumilar G, Tanudireja AS, Rohmatulloh FG, Maulana FA, Baroroh U, Hardianto A, Maharani R, Nurainy N, Wijayadikusumah AR, Ristandi RB, Atmosukarto IIC, Subroto T. Coarse-grained molecular dynamics-guided immunoinformatics to explain the binder and non-binder classification of Cytotoxic T-cell epitope for SARS-CoV-2 peptide-based vaccine discovery. PLoS One 2023; 18:e0292156. [PMID: 37796941 PMCID: PMC10553366 DOI: 10.1371/journal.pone.0292156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/13/2023] [Indexed: 10/07/2023] Open
Abstract
Epitope-based peptide vaccine can elicit T-cell immunity against SARS-CoV-2 to clear the infection. However, finding the best epitope from the whole antigen is challenging. A peptide screening using immunoinformatics usually starts from MHC-binding peptide, immunogenicity, cross-reactivity with the human proteome, to toxicity analysis. This pipeline classified the peptides into three categories, i.e., strong-, weak-, and non-binder, without incorporating the structural aspect. For this reason, the molecular detail that discriminates the binders from non-binder is interesting to be investigated. In this study, five CTL epitopes against HLA-A*02:01 were identified from the coarse-grained molecular dynamics-guided immunoinformatics screening. The strong binder showed distinctive activities from the non-binder in terms of structural and energetic properties. Furthermore, the second residue from the nonameric peptide was most important in the interaction with HLA-A*02:01. By understanding the nature of MHC-peptide interaction, we hoped to improve the chance of finding the best epitope for a peptide vaccine candidate.
Collapse
Affiliation(s)
- Muhammad Yusuf
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Padjadjaran, Bandung, West Java, Indonesia
- Research Center for Molecular Biotechnology and Bioinformatics, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Wanda Destiarani
- Research Center for Molecular Biotechnology and Bioinformatics, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Wahyu Widayat
- Faculty of Pharmacy, Pharmaceutical Biology Science, Universitas Mulawarman, Samarinda, East Kalimantan, Indonesia
| | - Yosua Yosua
- Research Center for Molecular Biotechnology and Bioinformatics, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Gilang Gumilar
- Research Center for Electronics, National Research and Innovation Agency Republic of Indonesia (BRIN), Bandung, West Java, Indonesia
| | - Angelica Shalfani Tanudireja
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Fauzian Giansyah Rohmatulloh
- Research Center for Molecular Biotechnology and Bioinformatics, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Farhan Azhwin Maulana
- Research Center for Molecular Biotechnology and Bioinformatics, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Umi Baroroh
- Research Center for Molecular Biotechnology and Bioinformatics, Universitas Padjadjaran, Bandung, West Java, Indonesia
- Department of Biotechnology, Indonesian School of Pharmacy, Bandung, West Java, Indonesia
| | - Ari Hardianto
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Rani Maharani
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Padjadjaran, Bandung, West Java, Indonesia
| | - Neni Nurainy
- Department of Research and Development, PT Bio Farma, Bandung, West Java, Indonesia
| | | | - Ryan B. Ristandi
- West Java Provincial Reference Laboratory, Bandung, West Java, Indonesia
| | | | - Toto Subroto
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Padjadjaran, Bandung, West Java, Indonesia
- Research Center for Molecular Biotechnology and Bioinformatics, Universitas Padjadjaran, Bandung, West Java, Indonesia
| |
Collapse
|
5
|
Bekker GJ, Numoto N, Kawasaki M, Hayashi T, Yabuno S, Kozono Y, Shimizu T, Kozono H, Ito N, Oda M, Kamiya N. Elucidation of binding mechanism, affinity, and complex structure between mWT1 tumor-associated antigen peptide and HLA-A*24:02. Protein Sci 2023; 32:e4775. [PMID: 37661929 PMCID: PMC10510467 DOI: 10.1002/pro.4775] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/02/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
We have applied our advanced computational and experimental methodologies to investigate the complex structure and binding mechanism of a modified Wilms' Tumor 1 (mWT1) protein epitope to the understudied Asian-dominant allele HLA-A*24:02 (HLA-A24) in aqueous solution. We have applied our developed multicanonical molecular dynamics (McMD)-based dynamic docking method to analyze the binding pathway and mechanism, which we verified by comparing the highest probability structures from simulation with our experimentally solved x-ray crystal structure. Subsequent path sampling MD simulations elucidated the atomic details of the binding process and indicated that first an encounter complex is formed between the N-terminal's positive charge of the 9-residue mWT1 fragment peptide and a cluster of negative residues on the surface of HLA-A24, with the major histocompatibility complex (MHC) molecule preferring a predominantly closed conformation. The peptide first binds to this closed MHC conformation, forming an encounter complex, after which the binding site opens due to increased entropy of the binding site, allowing the peptide to bind to form the native complex structure. Further sequence and structure analyses also suggest that although the peptide loading complex would help with stabilizing the MHC molecule, the binding depends in a large part on the intrinsic affinity between the MHC molecule and the antigen peptide. Finally, our computational tools and analyses can be of great benefit to study the binding mechanism of different MHC types to their antigens, where it could also be useful in the development of higher affinity variant peptides and for personalized medicine.
Collapse
Affiliation(s)
- Gert-Jan Bekker
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Nobutaka Numoto
- Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Maki Kawasaki
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Kyoto, Japan
| | - Takahiro Hayashi
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Kyoto, Japan
| | - Saaya Yabuno
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Kyoto, Japan
| | - Yuko Kozono
- Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Takeyuki Shimizu
- Department of Immunology, Kochi Medical School, Kochi University, Nankoku-shi, Kochi, Japan
| | - Haruo Kozono
- Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Nobutoshi Ito
- Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Kyoto, Japan
| | - Narutoshi Kamiya
- Graduate School of Information Science, University of Hyogo, Kobe, Hyogo, Japan
| |
Collapse
|
6
|
Li L, Peng X, Batliwala M, Bouvier M. Crystal structures of MHC class I complexes reveal the elusive intermediate conformations explored during peptide editing. Nat Commun 2023; 14:5020. [PMID: 37596268 PMCID: PMC10439229 DOI: 10.1038/s41467-023-40736-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/08/2023] [Indexed: 08/20/2023] Open
Abstract
Studies have suggested that MHC class I (MHC I) molecules fluctuate rapidly between numerous conformational states and these motions support peptide sampling. To date, MHC I intermediates are largely uncharacterized experimentally and remain elusive. Here, we present x-ray crystal structures of HLA-B8 loaded with 20mer peptides that show pronounced distortions at the N-terminus of the groove. Long stretches of N-terminal amino acid residues are missing in the electron density maps creating an open-ended groove. Our structures also reveal highly unusual features in MHC I-peptide interaction at the N-terminus of the groove. Molecular dynamics simulations indicate that the complexes have varying degrees of conformational flexibility in a manner consistent with the structures. We suggest that our structures have captured the remarkable molecular dynamics of MHC I-peptide interaction. The visualization of peptide-dependent conformational motions in MHC I is a major step forward in our conceptual understanding of dynamics in high-affinity peptide selection.
Collapse
Affiliation(s)
- Lenong Li
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Xubiao Peng
- Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Mansoor Batliwala
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Marlene Bouvier
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA.
| |
Collapse
|
7
|
Amaya-Ramirez D, Martinez-Enriquez LC, Parra-López C. Usefulness of Docking and Molecular Dynamics in Selecting Tumor Neoantigens to Design Personalized Cancer Vaccines: A Proof of Concept. Vaccines (Basel) 2023; 11:1174. [PMID: 37514989 PMCID: PMC10386133 DOI: 10.3390/vaccines11071174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 07/30/2023] Open
Abstract
Personalized cancer vaccines based on neoantigens are a new and promising treatment for cancer; however, there are still multiple unresolved challenges to using this type of immunotherapy. Among these, the effective identification of immunogenic neoantigens stands out, since the in silico tools used generate a significant portion of false positives. Inclusion of molecular simulation techniques can refine the results these tools produce. In this work, we explored docking and molecular dynamics to study the association between the stability of peptide-HLA complexes and their immunogenicity, using as a proof of concept two HLA-A2-restricted neoantigens that were already evaluated in vitro. The results obtained were in accordance with the in vitro immunogenicity, since the immunogenic neoantigen ASTN1 remained bound at both ends to the HLA-A2 molecule. Additionally, molecular dynamic simulation suggests that position 1 of the peptide has a more relevant role in stabilizing the N-terminus than previously proposed. Likewise, the mutations may have a "delocalized" effect on the peptide-HLA interaction, which means that the mutated amino acid influences the intensity of the interactions of distant amino acids of the peptide with the HLA. These findings allow us to propose the inclusion of molecular simulation techniques to improve the identification of neoantigens for cancer vaccines.
Collapse
Affiliation(s)
| | - Laura Camila Martinez-Enriquez
- Grupo de Inmunología y Medicina Traslacional, Departamento de Microbiología, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá 111321, Colombia
| | - Carlos Parra-López
- Grupo de Inmunología y Medicina Traslacional, Departamento de Microbiología, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá 111321, Colombia
| |
Collapse
|
8
|
Desikan H, Kaur A, Pogozheva ID, Raghavan M. Effects of calreticulin mutations on cell transformation and immunity. J Cell Mol Med 2023; 27:1032-1044. [PMID: 36916035 PMCID: PMC10098294 DOI: 10.1111/jcmm.17713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/16/2023] Open
Abstract
Myeloproliferative neoplasms (MPNs) are cancers involving dysregulated production and function of myeloid lineage hematopoietic cells. Among MPNs, Essential thrombocythemia (ET), Polycythemia Vera (PV) and Myelofibrosis (MF), are driven by mutations that activate the JAK-STAT signalling pathway. Somatic mutations of calreticulin (CRT), an endoplasmic reticulum (ER)-localized lectin chaperone, are driver mutations in approximately 25% of ET and 35% of MF patients. The MPN-linked mutant CRT proteins have novel frameshifted carboxy-domain sequences and lack an ER retention motif, resulting in their secretion. Wild type CRT is a regulator of ER calcium homeostasis and plays a key role in the assembly of major histocompatibility complex (MHC) class I molecules, which are the ligands for antigen receptors of CD8+ T cells. Mutant CRT-linked oncogenesis results from the dysregulation of calcium signalling in cells and the formation of stable complexes of mutant CRT with myeloproliferative leukemia (MPL) protein, followed by downstream activation of the JAK-STAT signalling pathway. The intricate participation of CRT in ER protein folding, calcium homeostasis and immunity suggests the involvement of multiple mechanisms of mutant CRT-linked oncogenesis. In this review, we highlight recent findings related to the role of MPN-linked CRT mutations in the dysregulation of calcium homeostasis, MPL activation and immunity.
Collapse
Affiliation(s)
- Harini Desikan
- Department of Microbiology and ImmunologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Amanpreet Kaur
- Department of Microbiology and ImmunologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Irina D. Pogozheva
- Department of Medicinal ChemistryCollege of Pharmacy, University of MichiganAnn ArborMichiganUSA
| | - Malini Raghavan
- Department of Microbiology and ImmunologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| |
Collapse
|
9
|
Advancing our knowledge of antigen processing with computational modelling, structural biology, and immunology. Biochem Soc Trans 2023; 51:275-285. [PMID: 36645000 DOI: 10.1042/bst20220782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/09/2022] [Accepted: 01/03/2023] [Indexed: 01/17/2023]
Abstract
Antigen processing is an immunological mechanism by which intracellular peptides are transported to the cell surface while bound to Major Histocompatibility Complex molecules, where they can be surveyed by circulating CD8+ or CD4+ T-cells, potentially triggering an immunological response. The antigen processing pathway is a complex multistage filter that refines a huge pool of potential peptide ligands derived from protein degradation into a smaller ensemble for surface presentation. Each stage presents unique challenges due to the number of ligands, the polymorphic nature of MHC and other protein constituents of the pathway and the nature of the interactions between them. Predicting the ensemble of displayed peptide antigens, as well as their immunogenicity, is critical for improving T cell vaccines against pathogens and cancer. Our predictive abilities have always been hindered by an incomplete empirical understanding of the antigen processing pathway. In this review, we highlight the role of computational and structural approaches in improving our understanding of antigen processing, including structural biology, computer simulation, and machine learning techniques, with a particular focus on the MHC-I pathway.
Collapse
|
10
|
Lan BH, Becker M, Freund C. The mode of action of tapasin on major histocompatibility class I (MHC-I) molecules. J Biol Chem 2023; 299:102987. [PMID: 36758805 PMCID: PMC10040737 DOI: 10.1016/j.jbc.2023.102987] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 01/05/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023] Open
Abstract
Tapasin (Tsn) plays a critical role in antigen processing and presentation by major histocompatibility complex class I (MHC-I) molecules. The mechanism of Tsn-mediated peptide loading and exchange hinges on the conformational dynamics governing the interaction of Tsn and MHC-I with recent structural and functional studies pinpointing the critical sites of direct or allosteric regulation. In this review, we highlight these recent findings and relate them to the extensive molecular and cellular data that are available for these evolutionary interdependent proteins. Furthermore, allotypic differences of MHC-I with regard to the editing and chaperoning function of Tsn are reviewed and related to the mechanistic observations. Finally, evolutionary aspects of the mode of action of Tsn will be discussed, a short comparison with the Tsn-related molecule TAPBPR (Tsn-related protein) will be given, and the impact of Tsn on noncanonical MHC-I molecules will be described.
Collapse
Affiliation(s)
- By Huan Lan
- Institute of Chemistry & Biochemistry, Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Moritz Becker
- Institute of Chemistry & Biochemistry, Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Christian Freund
- Institute of Chemistry & Biochemistry, Laboratory of Protein Biochemistry, Freie Universität Berlin, Berlin, Germany.
| |
Collapse
|
11
|
Cassano T, Giamogante F, Calcagnini S, Romano A, Lavecchia AM, Inglese F, Paglia G, Bukke VN, Romano AD, Friuli M, Altieri F, Gaetani S. PDIA3 Expression Is Altered in the Limbic Brain Regions of Triple-Transgenic Mouse Model of Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24033005. [PMID: 36769334 PMCID: PMC9918299 DOI: 10.3390/ijms24033005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
In the present study, we used a mouse model of Alzheimer's disease (AD) (3×Tg-AD mice) to longitudinally analyse the expression level of PDIA3, a protein disulfide isomerase and endoplasmic reticulum (ER) chaperone, in selected brain limbic areas strongly affected by AD-pathology (amygdala, entorhinal cortex, dorsal and ventral hippocampus). Our results suggest that, while in Non-Tg mice PDIA3 levels gradually reduce with aging in all brain regions analyzed, 3×Tg-AD mice showed an age-dependent increase in PDIA3 levels in the amygdala, entorhinal cortex, and ventral hippocampus. A significant reduction of PDIA3 was observed in 3×Tg-AD mice already at 6 months of age, as compared to age-matched Non-Tg mice. A comparative immunohistochemistry analysis performed on 3×Tg-AD mice at 6 (mild AD-like pathology) and 18 (severe AD-like pathology) months of age showed a direct correlation between the cellular level of Aβ and PDIA3 proteins in all the brain regions analysed, even if with different magnitudes. Additionally, an immunohistochemistry analysis showed the presence of PDIA3 in all post-mitotic neurons and astrocytes. Overall, altered PDIA3 levels appear to be age- and/or pathology-dependent, corroborating the ER chaperone's involvement in AD pathology, and supporting the PDIA3 protein as a potential novel therapeutic target for the treatment of AD.
Collapse
Affiliation(s)
- Tommaso Cassano
- Department of Medical and Surgical Sciences, University of Foggia, Via L. Pinto 1, 71122 Foggia, Italy
| | - Flavia Giamogante
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Silvio Calcagnini
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Adele Romano
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Angelo Michele Lavecchia
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Francesca Inglese
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Giuliano Paglia
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Vidyasagar Naik Bukke
- Department of Medical and Surgical Sciences, University of Foggia, Via L. Pinto 1, 71122 Foggia, Italy
| | - Antonino Davide Romano
- Department of Medical and Surgical Sciences, University of Foggia, Via L. Pinto 1, 71122 Foggia, Italy
| | - Marzia Friuli
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Fabio Altieri
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
- Correspondence:
| | - Silvana Gaetani
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| |
Collapse
|
12
|
Li L, Peng X, Batliwala M, Bouvier M. Unusual crystal structures of MHC class I complexes reveal the elusive intermediate conformations explored during peptide editing in antigen presentation. RESEARCH SQUARE 2023:rs.3.rs-2500847. [PMID: 36747752 PMCID: PMC9901037 DOI: 10.21203/rs.3.rs-2500847/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Studies have suggested that MHC class I (MHC I) molecules fluctuate rapidly between conformational states as they sample peptides for potential ligands. To date, MHC I intermediates are largely uncharacterized experimentally and remain elusive. We present x-ray crystal structures of HLA-B8 loaded with 20mer peptides that show significant conformational heterogeneity at the N-terminus of the groove. Long stretches of N-terminal residues were missing in the electron density maps creating an unstructured and widely open-ended groove. Our structures also revealed highly unusual features in MHC I and peptide conformations, and in MHC I-peptide interaction at the N-terminus of the groove. Molecular dynamics simulations showed that the complexes have varying degrees of flexibility in a manner consistent with the structures. We suggest that our structures represent transient substates explored by MHC I molecules during peptide editing. The visualization of peptide-dependent conformational flexibility in MHC I groove is a major step forward in our conceptual understanding of peptide repertoire development in antigen presentation. Our study also raises questions about the role of the N-terminus of the groove in peptide editing.
Collapse
Affiliation(s)
- Lenong Li
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Xubiao Peng
- Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Mansoor Batliwala
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Marlene Bouvier
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| |
Collapse
|
13
|
Wingbermühle S, Schäfer LV. Partial peptide dissociation and binding groove plasticity in two major histocompatibility complex class I alleles - differences between alleles versus force field and sampling effects. RSC Adv 2022; 12:29908-29914. [PMID: 36321080 PMCID: PMC9580618 DOI: 10.1039/d2ra05324a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
Major histocompatibility complex class I (MHC I) reports a cell's health status by presenting antigenic peptides inside its binding groove. However, MHC I binding grooves can differ largely in their plasticity, from binding grooves that are conformationally stable by themselves to those that require a high-affinity peptide to be bound to attain conformational stability. These latter MHC I alleles are dependent on the C-terminus of the peptide that stabilizes the F-pocket region of their binding grooves. It has remained unclear to what extent a peptide-MHC I complex (pMHC I) can tolerate the (intermittent) partial dissociation of high-affinity peptides, especially of the peptide's N-terminus. Using bias exchange umbrella sampling (BEUS), a technique to achieve enhanced sampling in molecular dynamics (MD) simulations, we obtained the free-energy profiles of the N-terminal dissociation of a respective high-affinity peptide from HLA-B*35:01 and HLA-B*44:02, two alleles on opposite ends of the scale regarding binding groove plasticity. The potential of mean force (PMF) for HLA-B*35:01 was calculated for two different sets of starting structures and is compared with a PMF obtained previously with a different force field to disentangle allele differences from force field and sampling effects. For both alleles, the free-energy profiles indicate that the peptide N-terminus dissociates in a substantial fraction of the pMHC I, suggesting that their crystal structures with fully bound peptides only partially capture the dynamic conformational ensemble of pMHC I in solution, and thus in the cell. In solution, high-affinity peptides are likely to dissociate partially from two alleles of major histocompatibility complex I. Despite very similar free-energy profiles, two molecular dynamics force fields predict different underlying mechanisms.![]()
Collapse
|
14
|
Pharmacogenetic Variation and Its Clinical Relevance in a Latin American Rural Population. Int J Mol Sci 2022; 23:ijms231911758. [PMID: 36233078 PMCID: PMC9570141 DOI: 10.3390/ijms231911758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/21/2022] [Accepted: 09/27/2022] [Indexed: 11/17/2022] Open
Abstract
Latin-American populations have been largely underrepresented in genomic studies of drug response and disease susceptibility. In this paper, we present a genome-wide Chilean dataset from Talca based on the Illumina Global Screening Array. This let us to compare the frequency of gene variants involved in response to drugs among our population and others, taking data from the 1000 Genomes Project. We found four single-nucleotide polymorphisms with low prevalence in Chileans when compared with African, Amerindian, East and South Asian, and European populations: rs2819742 (RYR2), rs2631367 (SLC22A5), rs1063320 (HLA-G), and rs1042522 (TP53). Moreover, two markers showed significant differences between lower and higher proportion of Mapuche ancestry groups: rs1719247 (located in an intergenic region in chromosome 15; p-value = 6.17 × 10−5, Bonferroni corrected p-value = 0.02) and rs738409 (A nonsynonymous gene variant in the PNPLA3 gene; p-value = 9.02 × 10−5, Bonferroni corrected p-value = 0.04). All of these polymorphisms have been shown to be associated with diverse pathologies, such as asthma, cancer, or chronic hepatitis B, or to be involved in a different response to drugs, such as metformin, HMG-CoA reductase inhibitors, or simvastatin. The present work provides a pharmacogenetic landscape of an understudied Latin American rural population and supports the notion that pharmacogenetic studies in admixed populations should consider ancestry for a higher accuracy of the results. Our study stresses the relevance of the pharmacogenomic research to provide guidance for a better choice of the best treatment for each individual in a population with admixed ancestry.
Collapse
|
15
|
Structural mechanism of tapasin-mediated MHC-I peptide loading in antigen presentation. Nat Commun 2022; 13:5470. [PMID: 36115831 PMCID: PMC9482634 DOI: 10.1038/s41467-022-33153-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/26/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractLoading of MHC-I molecules with peptide by the catalytic chaperone tapasin in the peptide loading complex plays a critical role in antigen presentation and immune recognition. Mechanistic insight has been hampered by the lack of detailed structural information concerning tapasin–MHC-I. We present here crystal structures of human tapasin complexed with the MHC-I molecule HLA-B*44:05, and with each of two anti-tapasin antibodies. The tapasin-stabilized peptide-receptive state of HLA-B*44:05 is characterized by distortion of the peptide binding groove and destabilization of the β2-microglobulin interaction, leading to release of peptide. Movements of the membrane proximal Ig-like domains of tapasin, HLA-B*44:05, and β2-microglobulin accompany the transition to a peptide-receptive state. Together this ensemble of crystal structures provides insights into a distinct mechanism of tapasin-mediated peptide exchange.
Collapse
|
16
|
McShan AC, Devlin CA, Papadaki GF, Sun Y, Green AI, Morozov GI, Burslem GM, Procko E, Sgourakis NG. TAPBPR employs a ligand-independent docking mechanism to chaperone MR1 molecules. Nat Chem Biol 2022; 18:859-868. [PMID: 35725941 PMCID: PMC9703140 DOI: 10.1038/s41589-022-01049-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 04/28/2022] [Indexed: 11/08/2022]
Abstract
Chaperones tapasin and transporter associated with antigen processing (TAP)-binding protein related (TAPBPR) associate with the major histocompatibility complex (MHC)-related protein 1 (MR1) to promote trafficking and cell surface expression. However, the binding mechanism and ligand dependency of MR1/chaperone interactions remain incompletely characterized. Here in vitro, biochemical and computational studies reveal that, unlike MHC-I, TAPBPR recognizes MR1 in a ligand-independent manner owing to the absence of major structural changes in the MR1 α2-1 helix between empty and ligand-loaded molecules. Structural characterization using paramagnetic nuclear magnetic resonance experiments combined with restrained molecular dynamics simulations reveals that TAPBPR engages conserved surfaces on MR1 to induce similar adaptations to those seen in MHC-I/TAPBPR co-crystal structures. Finally, nuclear magnetic resonance relaxation dispersion experiments using 19F-labeled diclofenac show that TAPBPR can affect the exchange kinetics of noncovalent metabolites with the MR1 groove, serving as a catalyst. Our results support a role of chaperones in stabilizing nascent MR1 molecules to enable loading of endogenous or exogenous cargo.
Collapse
Affiliation(s)
- Andrew C McShan
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christine A Devlin
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Georgia F Papadaki
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi Sun
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Adam I Green
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Giora I Morozov
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - George M Burslem
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cancer Biology and Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
17
|
Walker-Sperling V, Digitale JC, Viard M, Martin MP, Bashirova A, Yuki Y, Ramsuran V, Kulkarni S, Naranbhai V, Li H, Anderson SK, Yum L, Clifford R, Kibuuka H, Ake J, Thomas R, Rowland-Jones S, Rek J, Arinaitwe E, Kamya M, Rodriguez-Barraquer I, Feeney ME, Carrington M. Genetic variation that determines TAPBP expression levels associates with the course of malaria in an HLA allotype-dependent manner. Proc Natl Acad Sci U S A 2022; 119:e2205498119. [PMID: 35858344 PMCID: PMC9303992 DOI: 10.1073/pnas.2205498119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/27/2022] [Indexed: 11/26/2022] Open
Abstract
HLA class I (HLA-I) allotypes vary widely in their dependence on tapasin (TAPBP), an integral component of the peptide-loading complex, to present peptides on the cell surface. We identified two single-nucleotide polymorphisms that regulate TAPBP messenger RNA (mRNA) expression in Africans, rs111686073 (G/C) and rs59097151 (A/G), located in an AP-2α transcription factor binding site and a microRNA (miR)-4486 binding site, respectively. rs111686073G and rs59097151A induced significantly higher TAPBP mRNA expression relative to the alternative alleles due to higher affinity for AP-2α and abrogation of miR-4486 binding, respectively. These variants associated with lower Plasmodium falciparum parasite prevalence and lower incidence of clinical malaria specifically among individuals carrying tapasin-dependent HLA-I allotypes, presumably by augmenting peptide loading, whereas tapasin-independent allotypes associated with relative protection, regardless of imputed TAPBP mRNA expression levels. Thus, an attenuated course of malaria may occur through enhanced breadth and/or magnitude of antigen presentation, an important consideration when evaluating vaccine efficacy.
Collapse
Affiliation(s)
- Victoria Walker-Sperling
- Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, 20892
| | - Jean C. Digitale
- Department of Medicine, University of California San Francisco, San Francisco, California, 94158
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, 94143
| | - Mathias Viard
- Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, 20892
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Maureen P. Martin
- Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, 20892
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Arman Bashirova
- Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, 20892
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Yuko Yuki
- Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, 20892
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Veron Ramsuran
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, 4041, South Africa
| | - Smita Kulkarni
- Texas Biomedical Research Institute, Host Pathogen Interaction Program, San Antonio, Texas, 78227
| | - Vivek Naranbhai
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, 4041, South Africa
- Dana Farber Cancer Institute, Department of Medical Oncology, Boston, Massachusetts, 02215
- MGH Cancer Center, Massachusetts General Hospital, Boston, Massachusetts, 02114
- Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, 02114
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, 4041, South Africa
| | - Hongchuan Li
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
- Laboratory of Cancer Immunometabolism, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Stephen K. Anderson
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
- Laboratory of Cancer Immunometabolism, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Lauren Yum
- U.S. Military HIV Research Program,, Walter Reed Army Institute of Research, Silver Spring, Maryland, 20910
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, 20817
| | - Robert Clifford
- U.S. Military HIV Research Program,, Walter Reed Army Institute of Research, Silver Spring, Maryland, 20910
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, 20817
| | - Hannah Kibuuka
- Makerere University Walter Reed Project, Kampala, Uganda
| | - Julie Ake
- U.S. Military HIV Research Program,, Walter Reed Army Institute of Research, Silver Spring, Maryland, 20910
| | - Rasmi Thomas
- U.S. Military HIV Research Program,, Walter Reed Army Institute of Research, Silver Spring, Maryland, 20910
| | - Sarah Rowland-Jones
- Viral Immunology Unit, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | | | - Margaret E. Feeney
- Department of Medicine, University of California San Francisco, San Francisco, California, 94158
- Department of Pediatrics, University of California San Francisco, San Francisco, California, 94158
| | - Mary Carrington
- Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, 20892
- Basic Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, 02139
| |
Collapse
|
18
|
Marzella DF, Parizi FM, van Tilborg D, Renaud N, Sybrandi D, Buzatu R, Rademaker DT, 't Hoen PAC, Xue LC. PANDORA: A Fast, Anchor-Restrained Modelling Protocol for Peptide: MHC Complexes. Front Immunol 2022; 13:878762. [PMID: 35619705 PMCID: PMC9127323 DOI: 10.3389/fimmu.2022.878762] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/07/2022] [Indexed: 11/21/2022] Open
Abstract
Deeper understanding of T-cell-mediated adaptive immune responses is important for the design of cancer immunotherapies and antiviral vaccines against pandemic outbreaks. T-cells are activated when they recognize foreign peptides that are presented on the cell surface by Major Histocompatibility Complexes (MHC), forming peptide:MHC (pMHC) complexes. 3D structures of pMHC complexes provide fundamental insight into T-cell recognition mechanism and aids immunotherapy design. High MHC and peptide diversities necessitate efficient computational modelling to enable whole proteome structural analysis. We developed PANDORA, a generic modelling pipeline for pMHC class I and II (pMHC-I and pMHC-II), and present its performance on pMHC-I here. Given a query, PANDORA searches for structural templates in its extensive database and then applies anchor restraints to the modelling process. This restrained energy minimization ensures one of the fastest pMHC modelling pipelines so far. On a set of 835 pMHC-I complexes over 78 MHC types, PANDORA generated models with a median RMSD of 0.70 Å and achieved a 93% success rate in top 10 models. PANDORA performs competitively with three pMHC-I modelling state-of-the-art approaches and outperforms AlphaFold2 in terms of accuracy while being superior to it in speed. PANDORA is a modularized and user-configurable python package with easy installation. We envision PANDORA to fuel deep learning algorithms with large-scale high-quality 3D models to tackle long-standing immunology challenges.
Collapse
Affiliation(s)
- Dario F Marzella
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, Netherlands
| | - Farzaneh M Parizi
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, Netherlands
| | - Derek van Tilborg
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, Netherlands.,Department of Biomedical Engineering, Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Nicolas Renaud
- Natural Sciences and Engineering section, Netherlands eScience Center, Amsterdam, Netherlands
| | - Daan Sybrandi
- Bijvoet Centre for Biomolecular Research, Faculty of Science - Chemistry, Utrecht University, Utrecht, Netherlands
| | - Rafaella Buzatu
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, Netherlands
| | - Daniel T Rademaker
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, Netherlands
| | - Peter A C 't Hoen
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, Netherlands
| | - Li C Xue
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, Netherlands
| |
Collapse
|
19
|
Xu H, Song K, Da LT. Dynamics of peptide loading into major histocompatibility complex class I molecules chaperoned by TAPBPR. Phys Chem Chem Phys 2022; 24:12397-12409. [PMID: 35575131 DOI: 10.1039/d2cp00423b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Major histocompatibility complex class I (MHC-I) molecules display antigenic peptides on the cell surface for T cell receptor scanning, thereby activating the immune response. Peptide loading into MHC-I molecules is thus a critical step during the antigen presentation process. Chaperone TAP-binding protein related (TAPBPR) plays a critical role in promoting high-affinity peptide loading into MHC-I, by discriminating against the low-affinity ones. However, the complete peptide loading dynamics into TAPBPR-bound MHC-I is still elusive. Here, we constructed kinetic network models based on hundreds of short-time MD simulations with an aggregated simulation time of ∼21.7 μs, and revealed, at atomic level, four key intermediate states of one antigenic peptide derived from melanoma-associated MART-1/Melan-A protein during its loading process into TAPBPR-bound MHC-I. We find that the TAPBPR binding at the MHC-I pocket-F can substantially reshape the distant pocket-B via allosteric regulations, which in turn promotes the following peptide N-terminal loading. Intriguingly, the partially loaded peptide could profoundly weaken the TAPBPR-MHC stability, promoting the dissociation of the TAPBPR scoop-loop (SL) region from the pocket-F to a more solvent-exposed conformation. Structural inspections further indicate that the peptide loading could remotely affect the SL binding site through both allosteric perturbations and direct contacts. In addition, another structural motif of TAPBPR, the jack hairpin region, was also found to participate in mediating the peptide editing. Our study sheds light on the detailed molecular mechanisms underlying the peptide loading process into TAPBPR-bound MHC-I and pinpoints the key structural factors responsible for dictating the peptide-loading dynamics.
Collapse
Affiliation(s)
- Honglin Xu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
| | - Kaiyuan Song
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
| | - Lin-Tai Da
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
| |
Collapse
|
20
|
Margulies DH, Taylor DK, Jiang J, Boyd LF, Ahmad J, Mage MG, Natarajan K. Chaperones and Catalysts: How Antigen Presentation Pathways Cope With Biological Necessity. Front Immunol 2022; 13:859782. [PMID: 35464465 PMCID: PMC9022212 DOI: 10.3389/fimmu.2022.859782] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Immune recognition by T lymphocytes and natural killer (NK) cells is in large part dependent on the identification of cell surface MHC molecules bearing peptides generated from either endogenous (MHC I) or exogenous (MHC II) dependent pathways. This review focuses on MHC I molecules that coordinately fold to bind self or foreign peptides for such surface display. Peptide loading occurs in an antigen presentation pathway that includes either the multimolecular peptide loading complex (PLC) or a single chain chaperone/catalyst, TAP binding protein, related, TAPBPR, that mimics a key component of the PLC, tapasin. Recent structural and dynamic studies of TAPBPR reveal details of its function and reflect on mechanisms common to tapasin. Regions of structural conservation among species suggest that TAPBPR and tapasin have evolved to satisfy functional complexities demanded by the enormous polymorphism of MHC I molecules. Recent studies suggest that these two chaperone/catalysts exploit structural flexibility and dynamics to stabilize MHC molecules and facilitate peptide loading.
Collapse
Affiliation(s)
- David H Margulies
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Daniel K Taylor
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Jiansheng Jiang
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Lisa F Boyd
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Javeed Ahmad
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Michael G Mage
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| | - Kannan Natarajan
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Molecular Biology Section, National Institutes of Health, Bethesda, MD, United States
| |
Collapse
|
21
|
Pishesha N, Harmand TJ, Ploegh HL. A guide to antigen processing and presentation. Nat Rev Immunol 2022; 22:751-764. [PMID: 35418563 DOI: 10.1038/s41577-022-00707-2] [Citation(s) in RCA: 164] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2022] [Indexed: 12/13/2022]
Abstract
Antigen processing and presentation are the cornerstones of adaptive immunity. B cells cannot generate high-affinity antibodies without T cell help. CD4+ T cells, which provide such help, use antigen-specific receptors that recognize major histocompatibility complex (MHC) molecules in complex with peptide cargo. Similarly, eradication of virus-infected cells often depends on cytotoxic CD8+ T cells, which rely on the recognition of peptide-MHC complexes for their action. The two major classes of glycoproteins entrusted with antigen presentation are the MHC class I and class II molecules, which present antigenic peptides to CD8+ T cells and CD4+ T cells, respectively. This Review describes the essentials of antigen processing and presentation. These pathways are divided into six discrete steps that allow a comparison of the various means by which antigens destined for presentation are acquired and how the source proteins for these antigens are tagged for degradation, destroyed and ultimately displayed as peptides in complex with MHC molecules for T cell recognition.
Collapse
Affiliation(s)
- Novalia Pishesha
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Society of Fellows, Harvard University, Cambridge, MA, USA.,Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Thibault J Harmand
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hidde L Ploegh
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
22
|
Mercier R, LaPointe P. The role of cellular proteostasis in anti-tumor immunity. J Biol Chem 2022; 298:101930. [PMID: 35421375 PMCID: PMC9108985 DOI: 10.1016/j.jbc.2022.101930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/21/2022] [Accepted: 03/31/2022] [Indexed: 12/25/2022] Open
Abstract
Immune checkpoint blockade therapy is perhaps the most important development in cancer treatment in recent memory. It is based on decades of investigation into the biology of immune cells and the role of the immune system in controlling cancer growth. While the molecular circuitry that governs the immune system in general - and anti-tumor immunity in particular - is intensely studied, far less attention has been paid to the role of cellular stress in this process. Proteostasis, intimately linked to cell stress responses, refers to the dynamic regulation of the cellular proteome and is maintained through a complex network of systems that govern the synthesis, folding, and degradation of proteins in the cell. Disruption of these systems can result in the loss of protein function, altered protein function, the formation of toxic aggregates, or pathologies associated with cell stress. However, the importance of proteostasis extends beyond its role in maintaining proper protein function; proteostasis governs how tolerant cells may be to mutations in protein coding genes and the overall half-life of proteins. Such gene expression changes may be associated with human diseases including neurodegenerative diseases, metabolic disease, and cancer and manifest at the protein level against the backdrop of the proteostasis network in any given cellular environment. In this review, we focus on the role of proteostasis in regulating immune responses against cancer as well the role of proteostasis in determining immunogenicity of cancer cells.
Collapse
Affiliation(s)
- Rebecca Mercier
- Department of Cell Biology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Paul LaPointe
- Department of Cell Biology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
23
|
Ballabio F, Broggini L, Paissoni C, Han X, Peqini K, Sala BM, Sun R, Sandalova T, Barbiroli A, Achour A, Pellegrino S, Ricagno S, Camilloni C. l- to d-Amino Acid Substitution in the Immunodominant LCMV-Derived Epitope gp33 Highlights the Sensitivity of the TCR Recognition Mechanism for the MHC/Peptide Structure and Dynamics. ACS OMEGA 2022; 7:9622-9635. [PMID: 35350306 PMCID: PMC8945122 DOI: 10.1021/acsomega.1c06964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Presentation of pathogen-derived epitopes by major histocompatibility complex I (MHC-I) can lead to the activation and expansion of specific CD8+ T cell clones, eventually resulting in the destruction of infected target cells. Altered peptide ligands (APLs), designed to elicit immunogenicity toward a wild-type peptide, may affect the overall stability of MHC-I/peptide (pMHC) complexes and modulate the recognition by T cell receptors (TCR). Previous works have demonstrated that proline substitution at position 3 (p3P) of different MHC-restricted epitopes, including the immunodominant LCMV-derived epitope gp33 and escape variants, may be an effective design strategy to increase epitope immunogenicity. These studies hypothesized that the p3P substitution increases peptide rigidity, facilitating TCR binding. Here, molecular dynamics simulations indicate that the p3P modification rigidifies the APLs in solution predisposing them for the MHC-I loading as well as once bound to H-2Db, predisposing them for TCR binding. Our results also indicate that peptide position 6, key for interaction of H-2Db/gp33 with the TCR P14, takes a suboptimal conformation before as well as after binding to the TCR. Analyses of H-2Db in complex with APLs, in which position 6 was subjected to an l- to d-amino acid modification, revealed small conformational changes and comparable pMHC thermal stability. However, the l- to d-modification reduced significantly the binding to P14 even in the presence of the p3P modification. Our combined data highlight the sensitivity of the TCR for the conformational dynamics of pMHC and provide further tools to dissect and modulate TCR binding and immunogenicity via APLs.
Collapse
Affiliation(s)
- Federico Ballabio
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
| | - Luca Broggini
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
- Institute
of Molecular and Translational Cardiology, IRCCS Policlinico San Donato, San Donato Milanese 20097, Italy
| | - Cristina Paissoni
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
| | - Xiao Han
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Kaliroi Peqini
- DISFARM,
Dipartimento di Scienze Farmaceutiche, Sezione Chimica Generale e
Organica, Università degli Studi
di Milano, Milano 20122, Italy
| | - Benedetta Maria Sala
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Renhua Sun
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Tatyana Sandalova
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Alberto Barbiroli
- Dipartimento
di Scienze per gli Alimenti, la Nutrizione e l’Ambiente, Università degli Studi di Milano, Milano 20122, Italy
| | - Adnane Achour
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Sara Pellegrino
- DISFARM,
Dipartimento di Scienze Farmaceutiche, Sezione Chimica Generale e
Organica, Università degli Studi
di Milano, Milano 20122, Italy
| | - Stefano Ricagno
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
- Institute
of Molecular and Translational Cardiology, IRCCS Policlinico San Donato, San Donato Milanese 20097, Italy
| | - Carlo Camilloni
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
| |
Collapse
|
24
|
Yamamori Y, Tomii K. Application of Homology Modeling by Enhanced Profile-Profile Alignment and Flexible-Fitting Simulation to Cryo-EM Based Structure Determination. Int J Mol Sci 2022; 23:ijms23041977. [PMID: 35216093 PMCID: PMC8879198 DOI: 10.3390/ijms23041977] [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: 12/17/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 12/03/2022] Open
Abstract
Application of cryo-electron microscopy (cryo-EM) is crucially important for ascertaining the atomic structure of large biomolecules such as ribosomes and protein complexes in membranes. Advances in cryo-EM technology and software have made it possible to obtain data with near-atomic resolution, but the method is still often capable of producing only a density map with up to medium resolution, either partially or entirely. Therefore, bridging the gap separating the density map and the atomic model is necessary. Herein, we propose a methodology for constructing atomic structure models based on cryo-EM maps with low-to-medium resolution. The method is a combination of sensitive and accurate homology modeling using our profile–profile alignment method with a flexible-fitting method using molecular dynamics simulation. As described herein, this study used benchmark applications to evaluate the model constructions of human two-pore channel 2 (one target protein in CASP13 with its structure determined using cryo-EM data) and the overall structure of Enterococcus hirae V-ATPase complex.
Collapse
Affiliation(s)
- Yu Yamamori
- Artificial Intelligence Research Center (AIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan;
| | - Kentaro Tomii
- Artificial Intelligence Research Center (AIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan;
- AIST-Tokyo Tech Real World Big-Data Computation Open Innovation Laboratory (RWBC-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
- Correspondence:
| |
Collapse
|
25
|
Chichiarelli S, Altieri F, Paglia G, Rubini E, Minacori M, Eufemi M. ERp57/PDIA3: new insight. Cell Mol Biol Lett 2022; 27:12. [PMID: 35109791 PMCID: PMC8809632 DOI: 10.1186/s11658-022-00315-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/18/2022] [Indexed: 12/15/2022] Open
Abstract
The ERp57/PDIA3 protein is a pleiotropic member of the PDIs family and, although predominantly located in the endoplasmic reticulum (ER), has indeed been found in other cellular compartments, such as the nucleus or the cell membrane. ERp57/PDIA3 is an important research target considering it can be found in various subcellular locations. This protein is involved in many different physiological and pathological processes, and our review describes new data on its functions and summarizes some ligands identified as PDIA3-specific inhibitors.
Collapse
Affiliation(s)
- Silvia Chichiarelli
- Department of Biochemical Sciences "A.Rossi-Fanelli", Sapienza University of Rome, P.le A.Moro 5, 00185, Rome, Italy.
| | - Fabio Altieri
- Department of Biochemical Sciences "A.Rossi-Fanelli", Sapienza University of Rome, P.le A.Moro 5, 00185, Rome, Italy
| | - Giuliano Paglia
- Department of Biochemical Sciences "A.Rossi-Fanelli", Sapienza University of Rome, P.le A.Moro 5, 00185, Rome, Italy
| | - Elisabetta Rubini
- Department of Biochemical Sciences "A.Rossi-Fanelli", Sapienza University of Rome, P.le A.Moro 5, 00185, Rome, Italy.,Enrico Ed Enrica Sovena" Foundation, Rome, Italy
| | - Marco Minacori
- Department of Biochemical Sciences "A.Rossi-Fanelli", Sapienza University of Rome, P.le A.Moro 5, 00185, Rome, Italy
| | - Margherita Eufemi
- Department of Biochemical Sciences "A.Rossi-Fanelli", Sapienza University of Rome, P.le A.Moro 5, 00185, Rome, Italy
| |
Collapse
|
26
|
Frozen motion: how cryo-EM changes the way we look at ABC transporters. Trends Biochem Sci 2021; 47:136-148. [PMID: 34930672 DOI: 10.1016/j.tibs.2021.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 12/18/2022]
Abstract
ATP-binding cassette (ABC) transporters are widely present molecular machines that transfer substrates across the cell membrane. ABC transporters are involved in numerous physiological processes and are often clinical targets. Structural biology is fundamental to obtain the molecular details underlying ABC transporter function and suggest approaches to modulate it. Until recently, X-ray crystallography has been the only method capable of providing high-resolution structures of ABC transporters. However, modern cryo-electron microscopy (cryo-EM) opens entirely new ways of studying these dynamic membrane proteins. Cryo-EM enables analyses of targets that resist X-ray crystallography, challenging multicomponent complexes, and the exploration of conformational dynamics. These unique capacities have turned cryo-EM into the dominant technique for structural studies of membrane proteins, including ABC transporters.
Collapse
|
27
|
Ilca FT, Boyle LH. The glycosylation status of MHC class I molecules impacts their interactions with TAPBPR. Mol Immunol 2021; 139:168-176. [PMID: 34543843 PMCID: PMC8524320 DOI: 10.1016/j.molimm.2021.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/16/2021] [Accepted: 09/11/2021] [Indexed: 11/20/2022]
Abstract
Glycosylation plays a crucial role in the folding, structure, quality control and trafficking of glycoproteins. Here, we explored whether the glycosylation status of MHC class I (MHC-I) molecules impacts their affinity for the peptide editor, TAPBPR. We demonstrate that the interaction between TAPBPR and MHC-I is stronger when MHC-I lacks a glycan. Subsequently, TAPBPR can dissociate peptides, even those of high affinity, more easily from non-glycosylated MHC-I compared to their glycosylated counterparts. In addition, TAPBPR is more resistant to peptide-mediated allosteric release from non-glycosylated MHC-I compared to species with a glycan attached. Consequently, we find the glycosylation status of HLA-A*68:02, -A*02:01 and -B*27:05 influences their ability to undergo TAPBPR-mediated peptide exchange. The discovery that the glycan attached to MHC-I significantly influences the affinity of their interactions with TAPBPR has important implications, on both an experimental level and in a biological context.
Collapse
Affiliation(s)
- F Tudor Ilca
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK.
| |
Collapse
|
28
|
Multiscale simulations of large complexes in conjunction with cryo-EM analysis. Curr Opin Struct Biol 2021; 72:27-32. [PMID: 34399155 DOI: 10.1016/j.sbi.2021.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 11/21/2022]
Abstract
The cellular environment is highly crowded with most proteins and RNA/DNA forming homomeric and heteromeric complexes. Essential questions regarding how these complexes switch between functional, rest, and abnormal states with regulators or modifications remain challenging and complicated. Here, we review the recent progress integrating cryoelectron microscopy and multiscale molecular modeling to understand the dynamics and function-related mechanism in protein-RNA/DNA complexes, protein-protein complexes/assemblies, and membrane protein complexes. One future direction of multiscale simulations will be to interpret the large complex multibody regulation in assembly-induced function enhancement in conjunction with advanced atomic resolution structural-biology techniques and specialized computing architectures.
Collapse
|
29
|
Palomar G, Dudek K, Migalska M, Arntzen JW, Ficetola GF, Jelić D, Jockusch E, Martínez-Solano I, Matsunami M, Shaffer HB, Vörös J, Waldman B, Wielstra B, Babik W. Coevolution between MHC class I and Antigen Processing Genes in salamanders. Mol Biol Evol 2021; 38:5092-5106. [PMID: 34375431 PMCID: PMC8557411 DOI: 10.1093/molbev/msab237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Proteins encoded by antigen-processing genes (APGs) provide major histocompatibility complex (MHC) class I (MHC-I) with antigenic peptides. In mammals, polymorphic multigenic MHC-I family is served by monomorphic APGs, whereas in certain nonmammalian species both MHC-I and APGs are polymorphic and coevolve within stable haplotypes. Coevolution was suggested as an ancestral gnathostome feature, presumably enabling only a single highly expressed classical MHC-I gene. In this view coevolution, while optimizing some aspects of adaptive immunity, would also limit its flexibility by preventing the expansion of classical MHC-I into a multigene family. However, some nonmammalian taxa, such as salamanders, have multiple highly expressed MHC-I genes, suggesting either that coevolution is relaxed or that it does not prevent the establishment of multigene MHC-I. To distinguish between these two alternatives, we use salamanders (30 species from 16 genera representing six families) to test, within a comparative framework, a major prediction of the coevolution hypothesis: the positive correlation between MHC-I and APG diversity. We found that MHC-I diversity explained both within-individual and species-wide diversity of two APGs, TAP1 and TAP2, supporting their coevolution with MHC-I, whereas no consistent effect was detected for the other three APGs (PSMB8, PSMB9, and TAPBP). Our results imply that although coevolution occurs in salamanders, it does not preclude the expansion of the MHC-I gene family. Contrary to the previous suggestions, nonmammalian vertebrates thus may be able to accommodate diverse selection pressures with flexibility granted by rapid expansion or contraction of the MHC-I family, while retaining the benefits of coevolution between MHC-I and TAPs.
Collapse
Affiliation(s)
- G Palomar
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Kraków, Poland
| | - K Dudek
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Kraków, Poland
| | - M Migalska
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Kraków, Poland
| | - J W Arntzen
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA leiden, Leiden, The Netherlands.,Institute of Biology Leiden, Leiden University, 2300 RA Leiden, The Netherlands
| | - G F Ficetola
- Department of Environmental Sciences and Policy, University of Milano, Italy.,Laboratoire d'Ecologie Alpine (LECA), CNRS, Université Grenoble Alpes and Université Savoie Mont Blanc, Grenoble, France
| | - D Jelić
- Croatian Institute for Biodiversity, Zagreb, Croatia
| | - E Jockusch
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT USA
| | - I Martínez-Solano
- Museo Nacional de Ciencias Naturales (MNCN), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - M Matsunami
- Department of Advanced Genomic and Laboratory Medicine, Graduate School of Medicine, University of the Ryukyus, Nishihara-cho, Japan
| | - H B Shaffer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA.,La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, USA
| | - J Vörös
- Department of Zoology, Hungarian Natural History Museum, Budapest, Hungary
| | - B Waldman
- Department of Integrative Biology, Oklahoma State University, Stillwater, Oklahoma 74078, USA.,School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - B Wielstra
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA leiden, Leiden, The Netherlands.,Institute of Biology Leiden, Leiden University, 2300 RA Leiden, The Netherlands
| | - W Babik
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Kraków, Poland
| |
Collapse
|
30
|
Bergmann AC, Kyllesbech C, Slibinskas R, Ciplys E, Højrup P, Trier NH, Houen G. Epitope Mapping of Monoclonal Antibodies to Calreticulin Reveals That Charged Amino Acids Are Essential for Antibody Binding. Antibodies (Basel) 2021; 10:antib10030031. [PMID: 34449535 PMCID: PMC8395503 DOI: 10.3390/antib10030031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/25/2021] [Accepted: 07/30/2021] [Indexed: 02/01/2023] Open
Abstract
Calreticulin is a chaperone protein, which is associated with myeloproliferative diseases. In this study, we used resin-bound peptides to characterize two monoclonal antibodies (mAbs) directed to calreticulin, mAb FMC 75 and mAb 16, which both have significantly contributed to understanding the biological function of calreticulin. The antigenicity of the resin-bound peptides was determined by modified enzyme-linked immunosorbent assay. Specific binding was determined to an 8-mer epitope located in the N-terminal (amino acids 34–41) and to a 12-mer peptide located in the C-terminal (amino acids 362–373). Using truncated peptides, the epitopes were identified as TSRWIESK and DEEQRLKEEED for mAb FMC 75 and mAb 16, respectively, where, especially the charged amino acids, were found to have a central role for a stable binding. Further studies indicated that the epitope of mAb FMC 75 is assessable in the oligomeric structure of calreticulin, making this epitope a potential therapeutic target.
Collapse
Affiliation(s)
| | - Cecilie Kyllesbech
- Department of Neurology, Rigshospitalet Glostrup, 2600 Glostrup, Denmark;
| | - Rimantas Slibinskas
- Institute of Biotechnology, University of Vilnius, 01513 Vilnius, Lithuania; (R.S.); (E.C.)
| | - Evaldas Ciplys
- Institute of Biotechnology, University of Vilnius, 01513 Vilnius, Lithuania; (R.S.); (E.C.)
| | - Peter Højrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark;
| | - Nicole Hartwig Trier
- Department of Neurology, Rigshospitalet Glostrup, 2600 Glostrup, Denmark;
- Correspondence: (N.H.T.); (G.H.)
| | - Gunnar Houen
- Department of Neurology, Rigshospitalet Glostrup, 2600 Glostrup, Denmark;
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark;
- Correspondence: (N.H.T.); (G.H.)
| |
Collapse
|
31
|
The role of MHC I protein dynamics in tapasin and TAPBPR-assisted immunopeptidome editing. Curr Opin Immunol 2021; 70:138-143. [PMID: 34265495 DOI: 10.1016/j.coi.2021.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 06/16/2021] [Accepted: 06/24/2021] [Indexed: 11/23/2022]
Abstract
Major Histocompatibility Complex class I (MHC I) molecules are highly polymorphic, with allotypes differing in peptide binding preferences, and in their dependence upon tapasin for optimal peptide selection. The tapasin dependence of MHC allotypes is inversely correlated with their self-editing ability, and underpinned by conformational plasticity. Recently, TAPBPR has been shown to enhance MHC I assembly via a chaperone-like function, and by editing the peptide repertoire of some MHC I allotypes. Structural analysis has shown TAPBPR binding changes the conformation and dynamics of MHC I, with MHC protein dynamics likely to determine the prevailing TAPBPR function: generically enhancing MHC I assembly by stabilising highly dynamic peptide-empty MHC I; and by editing the peptide repertoire of highly dynamic MHC I allotypes.
Collapse
|
32
|
Lan H, Abualrous ET, Sticht J, Fernandez LMA, Werk T, Weise C, Ballaschk M, Schmieder P, Loll B, Freund C. Exchange catalysis by tapasin exploits conserved and allele-specific features of MHC-I molecules. Nat Commun 2021; 12:4236. [PMID: 34244493 PMCID: PMC8271027 DOI: 10.1038/s41467-021-24401-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 06/18/2021] [Indexed: 11/29/2022] Open
Abstract
The repertoire of peptides presented by major histocompatibility complex class I (MHC-I) molecules on the cell surface is tailored by the ER-resident peptide loading complex (PLC), which contains the exchange catalyst tapasin. Tapasin stabilizes MHC-I molecules and promotes the formation of stable peptide-MHC-I (pMHC-I) complexes that serve as T cell antigens. Exchange of suboptimal by high-affinity ligands is catalyzed by tapasin, but the underlying mechanism is still elusive. Here we analyze the tapasin-induced changes in MHC-I dynamics, and find the catalyst to exploit two essential features of MHC-I. First, tapasin recognizes a conserved allosteric site underneath the α2-1-helix of MHC-I, ‘loosening’ the MHC-I F-pocket region that accomodates the C-terminus of the peptide. Second, the scoop loop11–20 of tapasin relies on residue L18 to target the MHC-I F-pocket, enabling peptide exchange. Meanwhile, tapasin residue K16 plays an accessory role in catalysis of MHC-I allotypes bearing an acidic F-pocket. Thus, our results provide an explanation for the observed allele-specificity of catalyzed peptide exchange. Tapasin is part of the peptide loading complex necessary for presenting antigenic peptides on MHC-I for the induction of adaptive immunity. Here the authors show that tapasin interacts with MHC-I in both conserved and allele-specific regions to promote antigen presentation, with tapasin L18 and K16 residues both implicated in this molecular interaction.
Collapse
Affiliation(s)
- Huan Lan
- Laboratory of Protein Biochemistry, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Esam T Abualrous
- Laboratory of Protein Biochemistry, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany.,Artificial Intelligence for the Sciences, Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
| | - Jana Sticht
- Laboratory of Protein Biochemistry, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany.,Core Facility BioSupraMol, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Laura Maria Arroyo Fernandez
- Laboratory of Protein Biochemistry, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Tamina Werk
- Laboratory of Protein Biochemistry, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Christoph Weise
- Laboratory of Protein Biochemistry, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany.,Core Facility BioSupraMol, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Martin Ballaschk
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Peter Schmieder
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Bernhard Loll
- Laboratory of Structural Biology, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Christian Freund
- Laboratory of Protein Biochemistry, Institute for Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany.
| |
Collapse
|
33
|
Truong HV, Sgourakis NG. Dynamics of MHC-I molecules in the antigen processing and presentation pathway. Curr Opin Immunol 2021; 70:122-128. [PMID: 34153556 PMCID: PMC8622473 DOI: 10.1016/j.coi.2021.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/20/2021] [Accepted: 04/30/2021] [Indexed: 01/07/2023]
Abstract
The endogenous antigen processing and presentation (APP) is a fundamental pathway found in jawed vertebrates, which allows for a set of epitope peptides sampled from the intracellular proteome to be assembled and displayed on class I proteins of the major histocompatibility complex (MHC-I). Peptide/MHC-I antigens enable different aspects of adaptive immunity to emerge, by providing a basis for recognition of self vs. non-self by T cells and Natural Killer (NK) cells. Pioneering studies of pMHC-I molecules and their higher-order protein complexes with molecular chaperones and membrane receptors have gleaned important insights into the peptide loading and antigen recognition mechanisms. While X-ray and cryoEM structures have provided us with static snapshots of different MHC-I assembly stages, complementary biophysical techniques have revealed that MHC-I molecules are highly mobile on a range of biologically relevant timescales, which bears importance for their assembly, peptide repertoire selection, membrane display and turnover. This review summarizes insights gained from experimental and simulation studies aimed at investigating MHC-I dynamics, and their functional implications.
Collapse
Affiliation(s)
- Hau V Truong
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA.
| |
Collapse
|
34
|
Hafstrand I, Aflalo A, Boyle LH. Why TAPBPR? Implications of an additional player in MHC class I peptide presentation. Curr Opin Immunol 2021; 70:90-94. [PMID: 34052734 DOI: 10.1016/j.coi.2021.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/15/2021] [Accepted: 04/30/2021] [Indexed: 10/21/2022]
Abstract
The peptide editor TAPBPR is the newest member of the major histocompatibility complex class I (MHC-I) antigen processing and presentation pathway. Since 2013, studies have explored the functions and mechanisms of action of this tapasin homolog. Here, we review the key insights gained from structural studies of the TAPBPR:MHC-I complex and the involvement of the TAPBPR loop in peptide exchange. However, despite recent advances, the question still remains: why do we need TAPBPR? The recent appreciation that different MHC-I allotypes vary in their ability to interact with TAPBPR, together with a role for TAPBPR in alternative presentation pathways highlights that much remains unknown concerning the biological need for TAPBPR.
Collapse
Affiliation(s)
- Ida Hafstrand
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom; Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
| | - Aure Aflalo
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom.
| |
Collapse
|
35
|
Abualrous ET, Sticht J, Freund C. Major histocompatibility complex (MHC) class I and class II proteins: impact of polymorphism on antigen presentation. Curr Opin Immunol 2021; 70:95-104. [PMID: 34052735 DOI: 10.1016/j.coi.2021.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/23/2021] [Accepted: 04/25/2021] [Indexed: 01/01/2023]
Abstract
The major histocompatibility complex (MHC) loci are amongst the most polymorphic regions in the genomes of vertebrates. In the human population, thousands of MHC gene variants (alleles) exist that translate into distinct allotypes equipped with overlapping but unique peptide binding profiles. Understanding the differential structural and dynamic properties of MHC alleles and their interaction with critical regulators of peptide exchange bears the potential for more personalized strategies of immune modulation in the context of HLA-associated diseases.
Collapse
Affiliation(s)
- Esam T Abualrous
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Jana Sticht
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Christian Freund
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany.
| |
Collapse
|
36
|
McShan AC, Devlin CA, Morozov GI, Overall SA, Moschidi D, Akella N, Procko E, Sgourakis NG. TAPBPR promotes antigen loading on MHC-I molecules using a peptide trap. Nat Commun 2021; 12:3174. [PMID: 34039964 PMCID: PMC8154891 DOI: 10.1038/s41467-021-23225-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 04/16/2021] [Indexed: 11/08/2022] Open
Abstract
Chaperones Tapasin and TAP-binding protein related (TAPBPR) perform the important functions of stabilizing nascent MHC-I molecules (chaperoning) and selecting high-affinity peptides in the MHC-I groove (editing). While X-ray and cryo-EM snapshots of MHC-I in complex with TAPBPR and Tapasin, respectively, have provided important insights into the peptide-deficient MHC-I groove structure, the molecular mechanism through which these chaperones influence the selection of specific amino acid sequences remains incompletely characterized. Based on structural and functional data, a loop sequence of variable lengths has been proposed to stabilize empty MHC-I molecules through direct interactions with the floor of the groove. Using deep mutagenesis on two complementary expression systems, we find that important residues for the Tapasin/TAPBPR chaperoning activity are located on a large scaffolding surface, excluding the loop. Conversely, loop mutations influence TAPBPR interactions with properly conformed MHC-I molecules, relevant for peptide editing. Detailed biophysical characterization by solution NMR, ITC and FP-based assays shows that the loop hovers above the MHC-I groove to promote the capture of incoming peptides. Our results suggest that the longer loop of TAPBPR lowers the affinity requirements for peptide selection to facilitate peptide loading under conditions and subcellular compartments of reduced ligand concentration, and to prevent disassembly of high-affinity peptide-MHC-I complexes that are transiently interrogated by TAPBPR during editing.
Collapse
Affiliation(s)
- Andrew C McShan
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Christine A Devlin
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Giora I Morozov
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Sarah A Overall
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Danai Moschidi
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Neha Akella
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA.
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
37
|
Thomas C, Tampé R. MHC I assembly and peptide editing - chaperones, clients, and molecular plasticity in immunity. Curr Opin Immunol 2021; 70:48-56. [PMID: 33689959 DOI: 10.1016/j.coi.2021.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 02/07/2021] [Indexed: 11/24/2022]
Abstract
Peptides presented on MHC I molecules allow the immune system to detect diseased cells. The displayed peptides typically stem from proteasomal degradation of cytoplasmic proteins and are translocated into the ER lumen where they are trimmed and loaded onto MHC I. Peptide translocation is carried out by the transporter associated with antigen processing, which forms the central building block of a dynamic assembly called the peptide-loading complex (PLC). By coordinating peptide transfer with MHC I loading and peptide optimization, the PLC is a linchpin in the adaptive immune system. Peptide loading and optimization is catalyzed by the PLC component tapasin and the PLC-independent TAPBPR, two MHC I-dedicated enzymes chaperoning empty or suboptimally loaded MHC I and selecting stable peptide-MHC I complexes in a process called peptide editing or proofreading. Recent structural and functional studies of peptide editing have dramatically improved our understanding of this pivotal event in antigen processing/presentation. This review is dedicated to Vincenzo Cerundolo (1959-2020) for his pioneering work in the field of antigen processing/presentation.
Collapse
Affiliation(s)
- Christoph Thomas
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, Frankfurt, 60438 Main, Germany.
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, Frankfurt, 60438 Main, Germany.
| |
Collapse
|