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Kinetic and thermodynamic studies of the interaction between activating and inhibitory Ly49 natural killer receptors and MHC class I molecules. Biochem J 2017; 474:179-194. [PMID: 27831490 DOI: 10.1042/bcj20160876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/01/2016] [Accepted: 11/09/2016] [Indexed: 11/17/2022]
Abstract
Natural killer (NK) cells are lymphocytes of the innate immune system that eliminate virally infected or malignantly transformed cells. NK cell function is regulated by diverse surface receptors that are both activating and inhibitory. Among them, the homodimeric Ly49 receptors control NK cell cytotoxicity by sensing major histocompatibility complex class I molecules (MHC-I) on target cells. Although crystal structures have been reported for Ly49/MHC-I complexes, the underlying binding mechanism has not been elucidated. Accordingly, we carried out thermodynamic and kinetic experiments on the interaction of four NK Ly49 receptors (Ly49G, Ly49H, Ly49I and Ly49P) with two MHC-I ligands (H-2Dd and H-2Dk). These Ly49s embrace the structural and functional diversity of the highly polymorphic Ly49 family. Combining surface plasmon resonance, fluorescence anisotropy and far-UV circular dichroism (CD), we determined that the best model to describe both inhibitory and activating Ly49/MHC-I interactions is one in which the two MHC-I binding sites of the Ly49 homodimer present similar binding constants for the two sites (∼106 M-1) with a slightly positive co-operativity in some cases, and without far-UV CD observable conformational changes. Furthermore, Ly49/MHC-I interactions are diffusion-controlled and enthalpy-driven. These features stand in marked contrast with the activation-controlled and entropy-driven interaction of Ly49s with the viral immunoevasin m157, which is characterized by strong positive co-operativity and conformational selection. These differences are explained by the distinct structures of Ly49/MHC-I and Ly49/m157 complexes. Moreover, they reflect the opposing roles of NK cells to rapidly scan for virally infected cells and of viruses to escape detection using immunoevasins such as m157.
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De Marzi MC, Todone M, Ganem MB, Wang Q, Mariuzza RA, Fernández MM, Malchiodi EL. Peptidoglycan recognition protein-peptidoglycan complexes increase monocyte/macrophage activation and enhance the inflammatory response. Immunology 2015; 145:429-42. [PMID: 25752767 DOI: 10.1111/imm.12460] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 02/19/2015] [Accepted: 02/28/2015] [Indexed: 02/02/2023] Open
Abstract
Peptidoglycan recognition proteins (PGRP) are pattern recognition receptors that can bind or hydrolyse peptidoglycan (PGN). Four human PGRP have been described: PGRP-S, PGRP-L, PGRP-Iα and PGRP-Iβ. Mammalian PGRP-S has been implicated in intracellular destruction of bacteria by polymorphonuclear cells, PGRP-Iα and PGRP-Iβ have been found in keratinocytes and epithelial cells, and PGRP-L is a serum protein that hydrolyses PGN. We have expressed recombinant human PGRP and observed that PGRP-S and PGRP-Iα exist as monomer and disulphide dimer proteins. The PGRP dimers maintain their biological functions. We detected the PGRP-S dimer in human serum and polymorphonuclear cells, from where it is secreted after degranulation; these cells being a possible source of serum PGRP-S. Recombinant PGRP do not act as bactericidal or bacteriostatic agents in the assayed conditions; however, PGRP-S and PGRP-Iα cause slight damage in the bacterial membrane. Monocytes/macrophages increase Staphylococcus aureus phagocytosis in the presence of PGRP-S, PGRP-Iα and PGRP-Iβ. All PGRP bind to monocyte/macrophage membranes and are endocytosed by them. In addition, all PGRP protect cells from PGN-induced apoptosis. PGRP increase THP-1 cell proliferation and enhance activation by PGN. PGRP-S-PGN complexes increase the membrane expression of CD14, CD80 and CD86, and enhance secretion of interleukin-8, interleukin-12 and tumour necrosis factor-α, but reduce interleukin-10, clearly inducing an inflammatory profile.
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Affiliation(s)
- Mauricio C De Marzi
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, Buenos Aires, Argentina.,Instituto de Ecología y Desarrollo Sustentable (INEDES), Luján, Buenos Aires, Argentina
| | - Marcos Todone
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, Buenos Aires, Argentina.,Instituto de Ecología y Desarrollo Sustentable (INEDES), Luján, Buenos Aires, Argentina
| | - María B Ganem
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Qian Wang
- W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, USA
| | - Roy A Mariuzza
- W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, USA
| | - Marisa M Fernández
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Emilio L Malchiodi
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
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Forbes CA, Coudert JD. Mechanisms regulating NK cell activation during viral infection. Future Virol 2015. [DOI: 10.2217/fvl.14.106] [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
ABSTRACT NK cells constitute a population of lymphocytes involved in innate immune functions. They play a critical role in antiviral immune surveillance. Viruses have evolved with their host species for millions of years, each exerting a selective pressure upon the other. As a corollary, the pathways used by the immune system that are critical to control viral infection can be revealed by defining the role of viral gene products that are nonessential for virus replication. We relate here the battery of resources available to NK cells to recognize and eliminate viruses and reciprocally the immune evasion mechanisms developed by viruses to prevent NK cell activation.
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Affiliation(s)
- Catherine A Forbes
- Centre for Experimental Immunology, Lions Eye Institute, 2 Verdun St, Nedlands, WA 6009, Australia
| | - Jerome D Coudert
- Centre for Experimental Immunology, Lions Eye Institute, 2 Verdun St, Nedlands, WA 6009, Australia
- Centre for Ophthalmology & Vision Science, M517, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia
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Brizić I, Lenac Roviš T, Krmpotić A, Jonjić S. MCMV avoidance of recognition and control by NK cells. Semin Immunopathol 2014; 36:641-50. [DOI: 10.1007/s00281-014-0441-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 07/15/2014] [Indexed: 01/27/2023]
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Berry R, Vivian JP, Deuss FA, Balaji GR, Saunders PM, Lin J, Littler DR, Brooks AG, Rossjohn J. The structure of the cytomegalovirus-encoded m04 glycoprotein, a prototypical member of the m02 family of immunoevasins. J Biol Chem 2014; 289:23753-63. [PMID: 24982419 DOI: 10.1074/jbc.m114.584128] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ability of CMVs to evade the immune system of the host is dependent on the expression of a wide array of glycoproteins, many of which interfere with natural killer cell function. In murine CMV, two large protein families mediate this immune-evasive function. Although it is established that the m145 family members mimic the structure of MHC-I molecules, the structure of the m02 family remains unknown. The most extensively studied m02 family member is m04, a glycoprotein that escorts newly assembled MHC-I molecules to the cell surface, presumably to avoid "missing self" recognition. Here we report the crystal structure of the m04 ectodomain, thereby providing insight into this large immunoevasin family. m04 adopted a β-sandwich immunoglobulin variable (Ig-V)-like fold, despite sharing very little sequence identity with the Ig-V superfamily. In addition to the Ig-V core, m04 possesses several unique structural features that included an unusual β-strand topology, a number of extended loops and a prominent α-helix. The m04 interior was packed by a myriad of hydrophobic residues that form distinct clusters around two conserved tryptophan residues. This hydrophobic core was well conserved throughout the m02 family, thereby indicating that murine CMV encodes a number of Ig-V-like molecules. We show that m04 binds a range of MHC-I molecules with low affinity in a peptide-independent manner. Accordingly, the structure of m04, which represents the first example of an murine CMV encoded Ig-V fold, provides a basis for understanding the structure and function of this enigmatic and large family of immunoevasins.
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Affiliation(s)
- Richard Berry
- From the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences and
| | - Julian P Vivian
- From the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences and
| | - Felix A Deuss
- From the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences and
| | - Gautham R Balaji
- From the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences and
| | - Philippa M Saunders
- the Department of Microbiology & Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia, and
| | - Jie Lin
- the Department of Microbiology & Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia, and
| | - Dene R Littler
- From the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences and
| | - Andrew G Brooks
- the Department of Microbiology & Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia, and
| | - Jamie Rossjohn
- From the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences and the Institute of Infection and Immunity, Cardiff University, School of Medicine, Heath Park, Cardiff CF14 4XN, United Kingdom the Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia,
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Li Y, Mariuzza RA. Structural basis for recognition of cellular and viral ligands by NK cell receptors. Front Immunol 2014; 5:123. [PMID: 24723923 PMCID: PMC3972465 DOI: 10.3389/fimmu.2014.00123] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 03/10/2014] [Indexed: 11/13/2022] Open
Abstract
Natural killer (NK) cells are key components of innate immune responses to tumors and viral infections. NK cell function is regulated by NK cell receptors that recognize both cellular and viral ligands, including major histocompatibility complex (MHC), MHC-like, and non-MHC molecules. These receptors include Ly49s, killer immunoglobulin-like receptors, leukocyte immunoglobulin-like receptors, and NKG2A/CD94, which bind MHC class I (MHC-I) molecules, and NKG2D, which binds MHC-I paralogs such as the stress-induced proteins MICA and ULBP. In addition, certain viruses have evolved MHC-like immunoevasins, such as UL18 and m157 from cytomegalovirus, that act as decoy ligands for NK receptors. A growing number of NK receptor–ligand interaction pairs involving non-MHC molecules have also been identified, including NKp30–B7-H6, killer cell lectin-like receptor G1–cadherin, and NKp80–AICL. Here, we describe crystal structures determined to date of NK cell receptors bound to MHC, MHC-related, and non-MHC ligands. Collectively, these structures reveal the diverse solutions that NK receptors have developed to recognize these molecules, thereby enabling the regulation of NK cytolytic activity by both host and viral ligands.
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Affiliation(s)
- Yili Li
- W. M. Keck Laboratory for Structural Biology, Institute for Bioscience and Biotechnology Research, University of Maryland , Rockville, MD , USA ; Department of Cell Biology and Molecular Genetics, University of Maryland , College Park, MD , USA
| | - Roy A Mariuzza
- W. M. Keck Laboratory for Structural Biology, Institute for Bioscience and Biotechnology Research, University of Maryland , Rockville, MD , USA ; Department of Cell Biology and Molecular Genetics, University of Maryland , College Park, MD , USA
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