101
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Mermigka G, Amprazi M, Mentzelopoulou A, Amartolou A, Sarris PF. Plant and Animal Innate Immunity Complexes: Fighting Different Enemies with Similar Weapons. TRENDS IN PLANT SCIENCE 2020; 25:80-91. [PMID: 31677931 DOI: 10.1016/j.tplants.2019.09.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 05/06/2023]
Abstract
Both animals and plants express intracellular innate immunity receptors known as NLR (NOD-like receptors or nucleotide-binding domain and leucine-rich repeat receptors, respectively). For various mammalian systems, the specific formation of macromolecular structures, such as inflammasomes by activated NLR receptors, has been extensively reported. However, for plant organisms, the formation of such structures was an open scientific question for many years. This year, the first plant 'resistosome' structure was reported, revealing significant structural similarities to mammalian apoptosome and inflammasome structures. In this review, we summarize the key components comprising the mammalian apoptosome/inflammasome structures and the newly discovered plant resistosome, highlighting their commonalities and differences.
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Affiliation(s)
- Glykeria Mermigka
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, 70013, Crete, Greece
| | - Maria Amprazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, 70013, Crete, Greece; Department of Biology, University of Crete, 714 09 Heraklion, Crete, Greece
| | | | - Argyro Amartolou
- Department of Biology, University of Crete, 714 09 Heraklion, Crete, Greece
| | - Panagiotis F Sarris
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, 70013, Crete, Greece; Department of Biology, University of Crete, 714 09 Heraklion, Crete, Greece; Biosciences, University of Exeter, Geoffrey Pope Building, Exeter EX4 4QD, UK.
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102
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Chear CT, Nallusamy R, Canna SW, Chan KC, Baharin MF, Hishamshah M, Ghani H, Ripen AM, Mohamad SB. A novel de novo NLRC4 mutation reinforces the likely pathogenicity of specific LRR domain mutation. Clin Immunol 2019; 211:108328. [PMID: 31870725 DOI: 10.1016/j.clim.2019.108328] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/12/2019] [Accepted: 12/20/2019] [Indexed: 01/01/2023]
Abstract
Autoinflammatory disorders are characterized by dysregulated innate immune response, resulting in recurrent uncontrolled systemic inflammation and fever. Gain-of-function mutations in NLRC4 have been described to cause a range of autoinflammatory disorders. We report a twelve-year-old Malay girl with recurrent fever, skin erythema, and inflammatory arthritis. Whole exome sequencing and subsequent bidirectional Sanger sequencing identified a heterozygous missense mutation in NLRC4 (NM_001199138: c.1970A > T). This variant was predicted to be damaging in silico, was absent in public and local databases and occurred in a highly conserved residue in the leucine-rich repeat (LRR) domain. Cytokine analysis showed extremely high serum IL-18 and IL-18/CXCL9 ratio, consistent with other NLRC4-MAS patients. In summary, we identified the first patient with a novel de novo heterozygous NLRC4 gene mutation contributing to autoinflammatory disease in Malaysia. Our findings reinforce the likely pathogenicity of specific LRR domain mutations in NLRC4 and expand the clinical spectrum of NLRC4 mutations.
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Affiliation(s)
- Chai Teng Chear
- Primary Immunodeficiency Unit, Allergy and Immunology Research Centre, Institute for Medical Research, Ministry of Health, Malaysia; Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Revathy Nallusamy
- Pediatric Department, Penang General Hospital, Ministry of Health, Malaysia
| | - Scott W Canna
- Pediatrics and Immunology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kwai Cheng Chan
- Pediatric Department, Penang General Hospital, Ministry of Health, Malaysia
| | - Mohd Farid Baharin
- Primary Immunodeficiency Unit, Allergy and Immunology Research Centre, Institute for Medical Research, Ministry of Health, Malaysia
| | - Munirah Hishamshah
- Primary Immunodeficiency Unit, Allergy and Immunology Research Centre, Institute for Medical Research, Ministry of Health, Malaysia
| | - Hamidah Ghani
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Adiratna Mat Ripen
- Primary Immunodeficiency Unit, Allergy and Immunology Research Centre, Institute for Medical Research, Ministry of Health, Malaysia
| | - Saharuddin Bin Mohamad
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia; Centre of Research in Systems Biology, Structural Bioinformatics and Human Digital Imaging (CRYSTAL), University of Malaya, Kuala Lumpur, Malaysia.
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103
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Burdett H, Bentham AR, Williams SJ, Dodds PN, Anderson PA, Banfield MJ, Kobe B. The Plant "Resistosome": Structural Insights into Immune Signaling. Cell Host Microbe 2019; 26:193-201. [PMID: 31415752 DOI: 10.1016/j.chom.2019.07.020] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Plant innate immunity is triggered via direct or indirect recognition of pathogen effectors by the NLR family immune receptors. Mechanistic understanding of plant NLR function has relied on structural information from individual NLR domains and inferences from studies on animal NLRs. Recent reports of the cryo-EM structures of the Arabidopsis plant immune receptor ZAR1 in monomeric inactive and transition states, as well as the active oligomeric state or the "resistosome," have afforded a quantum leap in our understanding of how plant NLRs function. In this Review, we outline the recent structural findings and examine their implications for the activation of plant immune receptors more broadly. We also discuss how NLR signaling in plants, as illustrated by the ZAR1 structure, is analogous to innate immune receptor signaling mechanisms across kingdoms, drawing particular attention to the concept of signaling by cooperative assembly formation.
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Affiliation(s)
- Hayden Burdett
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Adam R Bentham
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Simon J Williams
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra 2601, Australia
| | - Peter N Dodds
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT 2601, Australia
| | - Peter A Anderson
- College of Sciences, Flinders University, Adelaide, SA 5001, Australia
| | - Mark J Banfield
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia.
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104
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Adachi H, Contreras MP, Harant A, Wu CH, Derevnina L, Sakai T, Duggan C, Moratto E, Bozkurt TO, Maqbool A, Win J, Kamoun S. An N-terminal motif in NLR immune receptors is functionally conserved across distantly related plant species. eLife 2019; 8:e49956. [PMID: 31774397 PMCID: PMC6944444 DOI: 10.7554/elife.49956] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 11/23/2019] [Indexed: 12/19/2022] Open
Abstract
The molecular codes underpinning the functions of plant NLR immune receptors are poorly understood. We used in vitro Mu transposition to generate a random truncation library and identify the minimal functional region of NLRs. We applied this method to NRC4-a helper NLR that functions with multiple sensor NLRs within a Solanaceae receptor network. This revealed that the NRC4 N-terminal 29 amino acids are sufficient to induce hypersensitive cell death. This region is defined by the consensus MADAxVSFxVxKLxxLLxxEx (MADA motif) that is conserved at the N-termini of NRC family proteins and ~20% of coiled-coil (CC)-type plant NLRs. The MADA motif matches the N-terminal α1 helix of Arabidopsis NLR protein ZAR1, which undergoes a conformational switch during resistosome activation. Immunoassays revealed that the MADA motif is functionally conserved across NLRs from distantly related plant species. NRC-dependent sensor NLRs lack MADA sequences indicating that this motif has degenerated in sensor NLRs over evolutionary time.
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Affiliation(s)
- Hiroaki Adachi
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Mauricio P Contreras
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Adeline Harant
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Chih-hang Wu
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Lida Derevnina
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Toshiyuki Sakai
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Cian Duggan
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - Eleonora Moratto
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - Tolga O Bozkurt
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - Abbas Maqbool
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Joe Win
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
| | - Sophien Kamoun
- The Sainsbury LaboratoryUniversity of East Anglia, Norwich Research ParkNorwichUnited Kingdom
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105
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Lai L, Yang G, Yao X, Wang L, Zhan Y, Yu M, Yin R, Li C, Yang X, Ge C. NLRC4 Mutation in flagellin-derived peptide CBLB502 ligand-binding domain reduces the inflammatory response but not radioprotective activity. JOURNAL OF RADIATION RESEARCH 2019; 60:780-785. [PMID: 31599956 PMCID: PMC6873615 DOI: 10.1093/jrr/rrz062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/25/2019] [Indexed: 06/10/2023]
Abstract
Bacterial flagellin is a pathogen-associated molecular pattern recognized by surface-localized Toll-like receptor 5 (TLR5) and cytosolic NOD-like receptor protein 4 (NLRC4). CBLB502, derived from Salmonella flagellin, exhibits high radioprotective efficacy in mice and primates by regulating TLR5 and the nuclear factor kappa B (NF-κB) signaling pathway. In this study, we examined the effects of CBLB502 and mutations in its NLRC4- and TLR5-binding domains on radioprotective efficacy and the immune inflammatory response. The results showed that CBLB502 mutation with I213A in the TLR5-binding domain significantly reduced NF-κB activity and radioprotective activity, whereas CBLB502 mutation with L292A in NLRC4-binding domain did not. Additionally, CBLB502 with both mutations greatly reduced NF-κB activity and eliminated radioprotection in mice. In contrast, NLRC4-binding domain mutation reduced the secretion of inflammatory interleukin-1β and interleukin-18. CBLB502 exerts its radioprotective effects through both the TLR5 and NLRC4 pathways. Additionally, deletion in the NLRC4-binding domain did not reduce radioprotective activity but reduced the inflammatory response.
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Affiliation(s)
- Lili Lai
- Graduate School of Anhui Medical University, Hefei 230032, China
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Ganggang Yang
- College of Life Science, Henan Normal University; Xinxiang Key Laboratory of Genetic Engineering Medicine, Xinxiang 453731, China
| | - Xuelian Yao
- Graduate School of Anhui Medical University, Hefei 230032, China
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Lei Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Yiqun Zhan
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Miao Yu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Ronghua Yin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Changyan Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Xiaoming Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Changhui Ge
- Graduate School of Anhui Medical University, Hefei 230032, China
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China
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106
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Rai RC. Host inflammatory responses to intracellular invaders: Review study. Life Sci 2019; 240:117084. [PMID: 31759040 DOI: 10.1016/j.lfs.2019.117084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/13/2022]
Abstract
As soon as a pathogen invades through the physical barriers of its corresponding host, host mounts a series of protective immune response to get rid of the invading pathogen. Host's pattern recognition receptors (PRR), localized at the cellular surface, cytoplasm and also in the nucleus; recognises pathogen associated molecular patterns (PAMPs) and plays crucial role in directing the immune response to be specific. Inflammatory responses are among the earliest strategies to tackle the pathogen by the host and are tightly regulated by multiple molecular pathways. Inflammasomes are multi-subunit protein complex consisting of a receptor molecule viz. NLRP3, an adaptor molecule- Apoptosis-associated speck-like protein containing a CARD (ASC) and an executioner caspase. Upon infection and/or injury; inflammasome components assemble and oligomerizes leading to the auto cleavage of the pro-caspase-1 to its active form. The activated caspase-1 cleaves immature form of the pro-inflammatory cytokines to their mature form e.g. IL1-β and IL-18 which mount inflammatory response. Moreover, C-terminal end of the Gasdermin D molecule is also cleaved by the caspase-1. The activated N-terminal Gasdermin D molecule form pores in the infected cells leading to their pyroptosis. Hence, inflammasomes drive inflammation during infection and controls the establishment of the pathogen by mounting inflammatory response and activation of the pyroptotic cell death.
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Affiliation(s)
- Ramesh Chandra Rai
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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107
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Hidden Aspects of Valency in Immune System Regulation. Trends Immunol 2019; 40:1082-1094. [PMID: 31734148 DOI: 10.1016/j.it.2019.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/10/2019] [Accepted: 10/16/2019] [Indexed: 02/08/2023]
Abstract
Valency can be defined as the number of discrete interactions a biomolecule can engage in. Valency can be critical for function, such as determining whether a molecule acts as a scaffold for assembling large supramolecular complexes or forms a functional dimer. Here, we highlight the importance of the role of valency in regulating immune responses, with a focus on innate immunity. We discuss some of the ways in which valency itself is regulated through transcriptional, post-transcriptional, and post-translational modifications. Finally, we propose that the valency model can be applied at the whole cell level to study differences in individual cell responses with relevance to putative therapeutic applications.
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108
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Radaelli E, Santagostino SF, Sellers RS, Brayton CF. Immune Relevant and Immune Deficient Mice: Options and Opportunities in Translational Research. ILAR J 2019; 59:211-246. [PMID: 31197363 PMCID: PMC7114723 DOI: 10.1093/ilar/ily026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/03/2018] [Indexed: 12/29/2022] Open
Abstract
In 1989 ILAR published a list and description of immunodeficient rodents used in research. Since then, advances in understanding of molecular mechanisms; recognition of genetic, epigenetic microbial, and other influences on immunity; and capabilities in manipulating genomes and microbiomes have increased options and opportunities for selecting mice and designing studies to answer important mechanistic and therapeutic questions. Despite numerous scientific breakthroughs that have benefitted from research in mice, there is debate about the relevance and predictive or translational value of research in mice. Reproducibility of results obtained from mice and other research models also is a well-publicized concern. This review summarizes resources to inform the selection and use of immune relevant mouse strains and stocks, aiming to improve the utility, validity, and reproducibility of research in mice. Immune sufficient genetic variations, immune relevant spontaneous mutations, immunodeficient and autoimmune phenotypes, and selected induced conditions are emphasized.
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Affiliation(s)
- Enrico Radaelli
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Sara F Santagostino
- Department of Safety Assessment, Genentech, Inc., South San Francisco, California
| | | | - Cory F Brayton
- Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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109
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Matsushima N, Takatsuka S, Miyashita H, Kretsinger RH. Leucine Rich Repeat Proteins: Sequences, Mutations, Structures and Diseases. Protein Pept Lett 2019; 26:108-131. [PMID: 30526451 DOI: 10.2174/0929866526666181208170027] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022]
Abstract
Mutations in the genes encoding Leucine Rich Repeat (LRR) containing proteins are associated with over sixty human diseases; these include high myopia, mitochondrial encephalomyopathy, and Crohn's disease. These mutations occur frequently within the LRR domains and within the regions that shield the hydrophobic core of the LRR domain. The amino acid sequences of fifty-five LRR proteins have been published. They include Nod-Like Receptors (NLRs) such as NLRP1, NLRP3, NLRP14, and Nod-2, Small Leucine Rich Repeat Proteoglycans (SLRPs) such as keratocan, lumican, fibromodulin, PRELP, biglycan, and nyctalopin, and F-box/LRR-repeat proteins such as FBXL2, FBXL4, and FBXL12. For example, 363 missense mutations have been identified. Replacement of arginine, proline, or cysteine by another amino acid, or the reverse, is frequently observed. The diverse effects of the mutations are discussed based on the known structures of LRR proteins. These mutations influence protein folding, aggregation, oligomerization, stability, protein-ligand interactions, disulfide bond formation, and glycosylation. Most of the mutations cause loss of function and a few, gain of function.
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Affiliation(s)
- Norio Matsushima
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan.,Institute of Tandem Repeats, Noboribetsu 059-0464, Japan
| | - Shintaro Takatsuka
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hiroki Miyashita
- Institute of Tandem Repeats, Noboribetsu 059-0464, Japan.,Hokubu Rinsho Co., Ltd, Sapporo 060-0061, Japan
| | - Robert H Kretsinger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, United States
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110
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López-Yglesias AH, Lu CC, Zhao X, Chou T, VandenBos T, Strong RK, Smith KD. FliC's Hypervariable D3 Domain Is Required for Robust Anti-Flagellin Primary Antibody Responses. Immunohorizons 2019; 3:422-432. [PMID: 31488506 PMCID: PMC11650696 DOI: 10.4049/immunohorizons.1800061] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 08/13/2019] [Indexed: 11/19/2022] Open
Abstract
Bacterial flagellin is a well-known agonist of the innate immune system that induces proinflammatory responses through the TLR5 and Naip5/6 recognition pathways. Several clinical trials investigating flagellin fusion proteins have demonstrated promising results for inducing protective immunity toward influenza virus, which has been largely attributed to flagellin's ability to activate TLR5. Our laboratory previously demonstrated that the Salmonella enterica serovar Typhimurium flagellin protein, FliC, induces Ab responses in mice through a third pathway that is independent of TLR5, Casp1/11, and MyD88. In this study, we further define the structural features of FliC that contribute to this unknown third pathway. By destroying the Naip5/6 and TLR5 recognition sites, we demonstrate that neither were required for the TLR5-, inflammasome- and MyD88-independent Ab responses toward FliC. In contrast, deletion of FliC's D3 or D0/D1 domains eliminated primary anti-flagellin Ab responses. For optimal primary and secondary anti-flagellin Ab responses we show that TLR5, inflammasome recognition, and the D3 domain of FliC are essential for flagellin's robust immunogenicity. Our data demonstrate that the D3 domain of FliC influences immunogenicity independent of the known innate recognition sites in the D0/D1 domains to augment Ab production. Our results suggest full-length FliC is critical for optimal immunogenicity and Ab responses in flagellin-based vaccines.
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Affiliation(s)
| | - Chun-Chi Lu
- Department of Pathology, University of Washington, Seattle, WA 98195; and
| | - Xiaodan Zhao
- Department of Pathology, University of Washington, Seattle, WA 98195; and
| | - Tiffany Chou
- Department of Pathology, University of Washington, Seattle, WA 98195; and
| | - Tim VandenBos
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Roland K Strong
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Kelly D Smith
- Department of Pathology, University of Washington, Seattle, WA 98195; and
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111
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Feng B, Tang D. Mechanism of plant immune activation and signaling: Insight from the first solved plant resistosome structure. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:902-907. [PMID: 30950566 DOI: 10.1111/jipb.12814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
This commentary introduces an exciting breakthrough: the first solved structure of a plant NLR immune receptor complex. The significance of this work, including the similarity between the activation of NLRs from plants and animals, and potentially novel mechanism of immune signaling in plants, were discussed and put into perspective.
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Affiliation(s)
- Baomin Feng
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Dingzhong Tang
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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112
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Adachi H, Derevnina L, Kamoun S. NLR singletons, pairs, and networks: evolution, assembly, and regulation of the intracellular immunoreceptor circuitry of plants. CURRENT OPINION IN PLANT BIOLOGY 2019; 50:121-131. [PMID: 31154077 DOI: 10.1016/j.pbi.2019.04.007] [Citation(s) in RCA: 159] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/26/2019] [Accepted: 04/20/2019] [Indexed: 05/20/2023]
Abstract
NLRs are modular plant and animal proteins that are intracellular sensors of pathogen-associated molecules. Upon pathogen perception, NLRs trigger a potent broad-spectrum immune reaction known as the hypersensitive response. An emerging paradigm is that plant NLR immune receptors form networks with varying degrees of complexity. NLRs may have evolved from multifunctional singleton receptors, which combine pathogen detection (sensor activity) and immune signalling (helper or executor activity) into a single protein, to functionally specialized interconnected receptor pairs and networks. In this article, we highlight some of the recent advances in plant NLR biology by discussing models of NLR evolution, NLR complex formation, and how NLR (mis)regulation modulates immunity and autoimmunity. Multidisciplinary approaches are required to dissect the evolution, assembly, and regulation of the immune receptor circuitry of plants. With the new conceptual framework provided by the elucidation of the structure and activation mechanism of a plant NLR resistosome, this field is entering an exciting era of research.
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Affiliation(s)
- Hiroaki Adachi
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Lida Derevnina
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Sophien Kamoun
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, UK.
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113
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de Alba E. Structure, interactions and self-assembly of ASC-dependent inflammasomes. Arch Biochem Biophys 2019; 670:15-31. [PMID: 31152698 PMCID: PMC8455077 DOI: 10.1016/j.abb.2019.05.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/10/2019] [Accepted: 05/28/2019] [Indexed: 12/12/2022]
Abstract
The inflammasome is a multi-protein platform that assembles upon the presence of cues derived from infection or tissue damage, and triggers the inflammatory response. Inflammasome components include sensor proteins that detect danger signals, procaspase 1 and the adapter ASC (apoptosis-associated speck-like protein containing a CARD) tethering these molecules together. Upon inflammasome assembly, procaspase 1 self-activates and renders functional cytokines to arbitrate in the defense mechanism. This assembly is mediated by self-association and protein interactions via Death Domains. The inflammasome plays a critical role in innate immunity and its dysregulation is the culprit of many autoimmune disorders. An in-depth understanding of the factors involved in inflammasome assembly could help fight these conditions. This review describes our current knowledge on the biophysical aspects of inflammasome formation from the perspective of ASC. The specific characteristics of the three-dimensional solution structure and interdomain dynamics of ASC are explained in relation to its function in inflammasome assembly. Additionally, the review elaborates on the identification of ASC interacting surfaces at the amino acid level using NMR techniques. Finally, the macrostructures formed by full-length ASC and its two Death Domains studied with Transmission Electron Microscopy are compared in the context of a directional model for inflammasome assembly.
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Affiliation(s)
- Eva de Alba
- Department of Bioengineering. School of Engineering. University of California, Merced, 5200 North Lake Road, Merced, CA, 95343, USA.
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114
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Viewing Legionella pneumophila Pathogenesis through an Immunological Lens. J Mol Biol 2019; 431:4321-4344. [PMID: 31351897 DOI: 10.1016/j.jmb.2019.07.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/25/2019] [Accepted: 07/13/2019] [Indexed: 12/14/2022]
Abstract
Legionella pneumophila is the causative agent of the severe pneumonia Legionnaires' disease. L. pneumophila is ubiquitously found in freshwater environments, where it replicates within free-living protozoa. Aerosolization of contaminated water supplies allows the bacteria to be inhaled into the human lung, where L. pneumophila can be phagocytosed by alveolar macrophages and replicate intracellularly. The Dot/Icm type IV secretion system (T4SS) is one of the key virulence factors required for intracellular bacterial replication and subsequent disease. The Dot/Icm apparatus translocates more than 300 effector proteins into the host cell cytosol. These effectors interfere with a variety of cellular processes, thus enabling the bacterium to evade phagosome-lysosome fusion and establish an endoplasmic reticulum-derived Legionella-containing vacuole, which facilitates bacterial replication. In turn, the immune system has evolved numerous strategies to recognize intracellular bacteria such as L. pneumophila, leading to potent inflammatory responses that aid in eliminating infection. This review aims to provide an overview of L. pneumophila pathogenesis in the context of the host immune response.
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115
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Matyszewski M, Sohn J. Preparation of filamentous proteins for electron microscopy visualization and reconstruction. Methods Enzymol 2019; 625:167-176. [PMID: 31455526 DOI: 10.1016/bs.mie.2019.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cryo electron microscopy (cryo-EM) has become a mainstream tool for determining the structures of macromolecular complexes at the atomic resolution. It has many advantages over other techniques such as X-ray crystallography and nuclear magnetic resonance (NMR). However, it also entails several challenges, a major one being preparation of an ideal sample. Recent studies have identified that DNA sensors and inflammasomes often assemble into filamentous oligomers, which poses a unique set of challenges in preparing ideal samples for high-resolution reconstruction using cryo-EM. This chapter will discuss how to overcome several major issues in cryo-EM sample preparation including construct design, screening using negative stain (ns) EM, and tips on working with filamentous proteins.
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Affiliation(s)
- Mariusz Matyszewski
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jungsan Sohn
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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116
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Gonçalves AV, Margolis SR, Quirino GFS, Mascarenhas DPA, Rauch I, Nichols RD, Ansaldo E, Fontana MF, Vance RE, Zamboni DS. Gasdermin-D and Caspase-7 are the key Caspase-1/8 substrates downstream of the NAIP5/NLRC4 inflammasome required for restriction of Legionella pneumophila. PLoS Pathog 2019; 15:e1007886. [PMID: 31251782 PMCID: PMC6622555 DOI: 10.1371/journal.ppat.1007886] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 07/11/2019] [Accepted: 06/03/2019] [Indexed: 11/24/2022] Open
Abstract
Inflammasomes are cytosolic multi-protein complexes that detect infection or cellular damage and activate the Caspase-1 (CASP1) protease. The NAIP5/NLRC4 inflammasome detects bacterial flagellin and is essential for resistance to the flagellated intracellular bacterium Legionella pneumophila. The effectors required downstream of NAIP5/NLRC4 to restrict bacterial replication remain unclear. Upon NAIP5/NLRC4 activation, CASP1 cleaves and activates the pore-forming protein Gasdermin-D (GSDMD) and the effector caspase-7 (CASP7). However, Casp1–/– (and Casp1/11–/–) mice are only partially susceptible to L. pneumophila and do not phenocopy Nlrc4–/–mice, because NAIP5/NLRC4 also activates CASP8 for restriction of L. pneumophila infection. Here we show that CASP8 promotes the activation of CASP7 and that Casp7/1/11–/– and Casp8/1/11–/– mice recapitulate the full susceptibility of Nlrc4–/– mice. Gsdmd–/– mice exhibit only mild susceptibility to L. pneumophila, but Gsdmd–/–Casp7–/– mice are as susceptible as the Nlrc4–/– mice. These results demonstrate that GSDMD and CASP7 are the key substrates downstream of NAIP5/NLRC4/CASP1/8 required for resistance to L. pneumophila. Inflammasomes are multi-protein complexes that detect infection and other stimuli and activate the Caspase-1 (CASP1) protease. The effectors required downstream of NAIP5/NLRC4 to restrict bacterial replication remain unclear. Active CASP1 cleaves and activates the pore-forming protein gasdermin D (GSDMD) to induce inflammation and cell death. We have previously shown that CASP8 is activated by the NAIP5/NLRC4 inflammasome independently of CASP1 and functions to restrict replication of the intracellular bacterium Legionella pneumophila. Here, we show that CASP7 is activated downstream of CASP8 and is required for CASP8-dependent restriction of L. pneumophila replication in macrophages and in vivo. In addition, CASP7 is also activated by CASP1. Taken together, these results imply that CASP7 and GSDMD are the two key caspase substrates downstream of NAIP5/NLRC4. In support of this hypothesis, we found that mice double deficient in CASP7 and GSDMD are more susceptible than the single knockouts and are as susceptible as the Nlrc4 deficient mice for restriction of L. pneumophila replication in vivo. Collectively, our data indicate that GSDMD and CASP7 are activated by CASP1 and induce cell death and restriction of bacterial infection. Therefore, GSDMD and multiple caspases (CASP1, CASP7 and CASP8) operate downstream of the NAIP5/NLRC4 inflammasome for restriction of infection by pathogenic bacteria.
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Affiliation(s)
- Augusto V. Gonçalves
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Shally R. Margolis
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Gustavo F. S. Quirino
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Danielle P. A. Mascarenhas
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Isabella Rauch
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Randilea D. Nichols
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Eduard Ansaldo
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Mary F. Fontana
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Russell E. Vance
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
- Howard Hughes Medical Institute, University of California, Berkeley, California, United States of America
- * E-mail: (REV); (DSZ)
| | - Dario S. Zamboni
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- * E-mail: (REV); (DSZ)
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117
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Wang J, Hu M, Wang J, Qi J, Han Z, Wang G, Qi Y, Wang HW, Zhou JM, Chai J. Reconstitution and structure of a plant NLR resistosome conferring immunity. Science 2019; 364:364/6435/eaav5870. [PMID: 30948527 DOI: 10.1126/science.aav5870] [Citation(s) in RCA: 500] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/13/2019] [Indexed: 12/27/2022]
Abstract
Nucleotide-binding, leucine-rich repeat receptors (NLRs) perceive pathogen effectors to trigger plant immunity. Biochemical mechanisms underlying plant NLR activation have until now remained poorly understood. We reconstituted an active complex containing the Arabidopsis coiled-coil NLR ZAR1, the pseudokinase RKS1, uridylated protein kinase PBL2, and 2'-deoxyadenosine 5'-triphosphate (dATP), demonstrating the oligomerization of the complex during immune activation. The cryo-electron microscopy structure reveals a wheel-like pentameric ZAR1 resistosome. Besides the nucleotide-binding domain, the coiled-coil domain of ZAR1 also contributes to resistosome pentamerization by forming an α-helical barrel that interacts with the leucine-rich repeat and winged-helix domains. Structural remodeling and fold switching during activation release the very N-terminal amphipathic α helix of ZAR1 to form a funnel-shaped structure that is required for the plasma membrane association, cell death triggering, and disease resistance, offering clues to the biochemical function of a plant resistosome.
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Affiliation(s)
- Jizong Wang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Meijuan Hu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China
| | - Jia Wang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jinfeng Qi
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China
| | - Zhifu Han
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Guoxun Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China
| | - Yijun Qi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Hong-Wei Wang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
| | - Jian-Min Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China.
| | - Jijie Chai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China. .,Max Planck Institute for Plant Breeding Research, Cologne, Germany.,Institute of Biochemistry, University of Cologne, Zuelpicher Strasse 47, 50674 Cologne, Germany
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118
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Wang J, Wang J, Hu M, Wu S, Qi J, Wang G, Han Z, Qi Y, Gao N, Wang HW, Zhou JM, Chai J. Ligand-triggered allosteric ADP release primes a plant NLR complex. Science 2019; 364:364/6435/eaav5868. [PMID: 30948526 DOI: 10.1126/science.aav5868] [Citation(s) in RCA: 299] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/13/2019] [Indexed: 12/16/2022]
Abstract
Pathogen recognition by nucleotide-binding (NB), leucine-rich repeat (LRR) receptors (NLRs) plays roles in plant immunity. The Xanthomonas campestris pv. campestris effector AvrAC uridylylates the Arabidopsis PBL2 kinase, and the latter (PBL2UMP) acts as a ligand to activate the NLR ZAR1 precomplexed with the RKS1 pseudokinase. Here we report the cryo-electron microscopy structures of ZAR1-RKS1 and ZAR1-RKS1-PBL2UMP in an inactive and intermediate state, respectively. The ZAR1LRR domain, compared with animal NLRLRR domains, is differently positioned to sequester ZAR1 in an inactive state. Recognition of PBL2UMP is exclusively through RKS1, which interacts with ZAR1LRR PBL2UMP binding stabilizes the RKS1 activation segment, which sterically blocks ZAR1 adenosine diphosphate (ADP) binding. This engenders a more flexible NB domain without conformational changes in the other ZAR1 domains. Our study provides a structural template for understanding plant NLRs.
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Affiliation(s)
- Jizong Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jia Wang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Meijuan Hu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China
| | - Shan Wu
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jinfeng Qi
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China
| | - Guoxun Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China
| | - Zhifu Han
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Yijun Qi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Ning Gao
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Hong-Wei Wang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
| | - Jian-Min Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Academy of Seed Design, Chinese Academy of Sciences, 100101 Beijing, China.
| | - Jijie Chai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China. .,Max Planck Institute for Plant Breeding Research, D-50829 Cologne, Germany.,Institute of Biochemistry, University of Cologne, Zuelpicher Str. 47, 50674 Cologne, Germany
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119
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Structural mechanism for NEK7-licensed activation of NLRP3 inflammasome. Nature 2019; 570:338-343. [PMID: 31189953 PMCID: PMC6774351 DOI: 10.1038/s41586-019-1295-z] [Citation(s) in RCA: 526] [Impact Index Per Article: 87.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/16/2019] [Indexed: 01/01/2023]
Abstract
The NLRP3 inflammasome can be activated by diverse stimuli, including nigericin, uric acid crystals, amyloid-β fibrils, and extracellular ATP. The mitotic kinase NEK7 licenses NLRP3 inflammasome assembly and activation in the interphase. Here we report a 3.8-Å cryo-electron microscopy structure of inactive human NLRP3 in complex with NEK7. The earring-shaped NLRP3 consists of curved leucine-rich repeat (LRR) and globular NACHT domains, whereas the C-terminal lobe of NEK7 nestles against both NLRP3 domains. Structural recognition between NLRP3 and NEK7 is confirmed by mutagenesis both in vitro and in cells. Modelling of an active NLRP3-NEK7 conformation based on the NLRC4 inflammasome predicts an additional contact between an NLRP3-bound NEK7 and a neighbouring NLRP3. Mutations on this interface abolish the ability of NEK7 or NLRP3 to rescue NLRP3 activation in NEK7KO or NLRP3KO cells. Taken together, these data suggest that NEK7 bridges adjacent NLRP3 subunits with bipartite interactions to mediate NLRP3 inflammasome activation.
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120
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Fusco WG, Duncan JA. Novel aspects of the assembly and activation of inflammasomes with focus on the NLRC4 inflammasome. Int Immunol 2019; 30:183-193. [PMID: 29617808 DOI: 10.1093/intimm/dxy009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 02/13/2018] [Indexed: 12/31/2022] Open
Abstract
Inflammasomes are multiprotein structures that activate caspase-1, support secretion of pro-inflammatory cytokines, IL-1β and IL-18, and also induce inflammatory programmed cell death, termed pyoptosis. Inflammasomes are activated in response to the detection of endogenous and microbially derived danger signals and are mediated by several classes of inflammasome-forming sensors. These include several nucleotide-binding proteins of the NOD-like receptor (NLR) family, including NLRP1, NLRP3 and NLRC4, as well as the proteins Absent in Melanoma 2 (AIM2) and Pyrin. Mutations in genes encoding some of these sensors have been found to be associated with gain-of-function monogenetic inflammatory disorders in humans. Genetic, biochemical and structural studies have begun to demonstrate how these proteins sense danger signals and to shed light on the step-by-step processes that are necessary for the assembly of inflammasomes, in both physiologic responses to pathogens and potentially in autoinflammatory conditions. Recent biochemical studies of pro-caspase-1 and an adapter protein known as ASC suggest that inflammasomes act to initiate self-generating effector filaments responsible for activating caspase-1 and initiating downstream signaling. These studies have suggested a model of molecular events from sensor activation to inflammasome formation that may describe processes that are universal to inflammasome formation.
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Affiliation(s)
- William G Fusco
- Department of Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joseph A Duncan
- Department of Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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121
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Brewer SM, Brubaker SW, Monack DM. Host inflammasome defense mechanisms and bacterial pathogen evasion strategies. Curr Opin Immunol 2019; 60:63-70. [PMID: 31174046 DOI: 10.1016/j.coi.2019.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/25/2019] [Accepted: 05/01/2019] [Indexed: 02/07/2023]
Abstract
Inflammasomes are a formidable armada of intracellular pattern recognition receptors. They recognize determinants of infection, such as foreign entities or danger signals within the host cell cytosol, rapidly executing innate immune defenses and initiating adaptive immune responses. Although inflammasomes are implicated in many diseases, they are especially critical in host protection against intracellular bacterial pathogens. Given this role, it is not surprising that many pathogens have evolved effective strategies to evade inflammasome activation. In this review, we will provide a brief summary of inflammasome activation during infection with the intent of highlighting recent advances in the field. Additionally, we will review known bacterial evasion strategies and countermeasures that impact pathogenesis.
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Affiliation(s)
- Susan M Brewer
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sky W Brubaker
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Denise M Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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122
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Haloupek N, Grob P, Tenthorey J, Vance RE, Nogales E. Cryo-EM studies of NAIP-NLRC4 inflammasomes. Methods Enzymol 2019; 625:177-204. [PMID: 31455527 PMCID: PMC7025759 DOI: 10.1016/bs.mie.2019.04.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The NAIP-NLRC4 family of inflammasomes are components of the innate immune system that sound a molecular alarm in the presence of intracellular pathogens. In this chapter, we provide an in-depth guide to using cryo-electron microscopy (cryo-EM) to investigate these inflammasomes, focusing especially on the techniques we used in our recent structural analysis of the NAIP5-NLRC4 inflammasome. We explain how to circumvent specific obstacles we encountered at each step, from sample preparation through data processing. The methods described here will be useful for further studies of the NAIP5-NLRC4 inflammasome and related supracomplexes involved in innate immune surveillance; they may also be useful for unrelated complexes that present similar issues, such as preferential orientations and compositional heterogeneity.
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Affiliation(s)
- Nicole Haloupek
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States.
| | - Patricia Grob
- Howard Hughes Medical Institute, UC Berkeley, Berkeley, CA, United States
| | - Jeannette Tenthorey
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States
| | - Russell E Vance
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States; Howard Hughes Medical Institute, UC Berkeley, Berkeley, CA, United States
| | - Eva Nogales
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States; Howard Hughes Medical Institute, UC Berkeley, Berkeley, CA, United States; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Lab, Berkeley, CA, United States.
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123
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Shen C, Sharif H, Xia S, Wu H. Structural and mechanistic elucidation of inflammasome signaling by cryo-EM. Curr Opin Struct Biol 2019; 58:18-25. [PMID: 31128494 DOI: 10.1016/j.sbi.2019.03.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 10/26/2022]
Abstract
The innate immune system forms an evolutionarily ancient line of defense against invading pathogens and endogenous danger signals. Within certain cells of innate immunity, including epithelial cells and macrophages, intricate molecular machineries named inflammasomes sense a wide array of stimuli to mount inflammatory responses. Dysregulation in inflammasome signaling leads to a wide range of immune disorders such as gout, Crohn's disease, and sepsis. Recent technological advances in cryo-electron microscopy (cryo-EM) have enabled the structural determination of several key signaling molecules in inflammasome pathways, from which macromolecular assembly emerges as a common mechanistic theme. Through the assembly of helical filaments, symmetric disks, and transmembrane pores, inflammasome pathways employ highly dynamic yet ordered processes to relay and amplify signals. These unprecedentedly detailed views of inflammasome signaling not only revolutionize our understanding of inflammation, but also pave the way for the development of therapeutics against inflammatory diseases.
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Affiliation(s)
- Chen Shen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Humayun Sharif
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Shiyu Xia
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
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Mitchell PS, Sandstrom A, Vance RE. The NLRP1 inflammasome: new mechanistic insights and unresolved mysteries. Curr Opin Immunol 2019; 60:37-45. [PMID: 31121538 DOI: 10.1016/j.coi.2019.04.015] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/18/2019] [Accepted: 04/19/2019] [Indexed: 11/25/2022]
Abstract
Nucleotide-binding domain, leucine-rich repeat (NLR) proteins constitute a diverse class of innate immune sensors that detect pathogens or stress-associated stimuli in plants and animals. Some NLRs are activated upon direct binding to pathogen-derived ligands. In contrast, we focus here on a vertebrate NLR called NLRP1 that responds to the enzymatic activities of pathogen effectors. We discuss a newly proposed 'functional degradation' mechanism that explains activation and assembly of NLRP1 into an oligomeric complex called an inflammasome. We also discuss how NLRP1 is activated by non-pathogen-associated triggers such as the anti-cancer drug Val-boroPro, or by human disease-associated mutations. Finally, we discuss how research on NLRP1 has led to additional biological insights, including the unexpected discovery of a new CARD8 inflammasome.
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Affiliation(s)
- Patrick S Mitchell
- Division of Immunology & Pathogenesis, Department of Molecular & Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, CA, USA
| | - Andrew Sandstrom
- Division of Immunology & Pathogenesis, Department of Molecular & Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - Russell E Vance
- Division of Immunology & Pathogenesis, Department of Molecular & Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
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125
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MCC950 directly targets the NLRP3 ATP-hydrolysis motif for inflammasome inhibition. Nat Chem Biol 2019; 15:556-559. [PMID: 31086327 DOI: 10.1038/s41589-019-0277-7] [Citation(s) in RCA: 662] [Impact Index Per Article: 110.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 03/22/2019] [Indexed: 11/09/2022]
Abstract
Inhibition of the NLRP3 inflammasome is a promising strategy for the development of new treatments for inflammatory diseases. MCC950 is a potent and specific small-molecule inhibitor of the NLRP3 pathway, but its molecular target is not defined. Here, we show that MCC950 directly interacts with the Walker B motif within the NLRP3 NACHT domain, thereby blocking ATP hydrolysis and inhibiting NLRP3 activation and inflammasome formation.
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126
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Animal NLRs continue to inform plant NLR structure and function. Arch Biochem Biophys 2019; 670:58-68. [PMID: 31071301 DOI: 10.1016/j.abb.2019.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/10/2019] [Accepted: 05/01/2019] [Indexed: 12/22/2022]
Abstract
Plant NLRs share many of the structural hallmarks of their animal counterparts. At a functional level, the central nucleotide-binding pocket appears to have binding and hydrolysis activities, similar to that of animal NLRs. The TIR domains of plant NLRs have been shown to self-associate, and there is emerging evidence that full-length plant NLRs may do so as well. It is therefore tempting to speculate that plant NLRs may form higher-order complexes similar to those of the mammalian inflammasome. Here we review the available knowledge on structure-function relationships in plant NLRs, focusing on how the information available on animal NLRs informs the mechanism of plant NLR function, and highlight the evidence that innate immunity signalling pathways in multicellular organisms often require the formation of higher-order protein complexes.
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127
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Adachi H, Kamoun S, Maqbool A. A resistosome-activated 'death switch'. NATURE PLANTS 2019; 5:457-458. [PMID: 31036914 DOI: 10.1038/s41477-019-0425-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Hiroaki Adachi
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Sophien Kamoun
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK.
| | - Abbas Maqbool
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
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128
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Hornick EE, Dagvadorj J, Zacharias ZR, Miller AM, Langlois RA, Chen P, Legge KL, Bishop GA, Sutterwala FS, Cassel SL. Dendritic cell NLRC4 regulates influenza A virus-specific CD4 T cell responses through FasL expression. J Clin Invest 2019; 129:2888-2897. [PMID: 31038471 DOI: 10.1172/jci124937] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Influenza A virus (IAV)-specific T cell responses are important correlates of protection during primary and subsequent infections. Generation and maintenance of robust IAV-specific T cell responses relies on T cell interactions with dendritic cells (DCs). In this study, we explore the role of nucleotide-binding domain leucine-rich repeat containing receptor family member NLRC4 in modulating the DC phenotype during IAV infection. Nlrc4-/- mice had worsened survival and increased viral titers during infection, normal innate immune cell recruitment and IAV-specific CD8 T cell responses, but severely blunted IAV-specific CD4 T cell responses compared to wild-type mice. The defect in the pulmonary IAV-specific CD4 T cell response was not a result of defective priming or migration of these cells in Nlrc4-/- mice but was instead due to an increase in FasL+ DCs, resulting in IAV-specific CD4 T cell death. Together, our data support a novel role for NLRC4 in regulating the phenotype of lung DCs during a respiratory viral infection, and thereby influencing the magnitude of protective T cell responses.
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Affiliation(s)
- Emma E Hornick
- Interdisciplinary Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Jargalsaikhan Dagvadorj
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Zeb R Zacharias
- Interdisciplinary Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Ann M Miller
- Department of Surgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Ryan A Langlois
- Center for Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Peter Chen
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Kevin L Legge
- Interdisciplinary Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Gail A Bishop
- Interdisciplinary Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Fayyaz S Sutterwala
- Interdisciplinary Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Suzanne L Cassel
- Interdisciplinary Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
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129
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130
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Yeoh BS, Gewirtz AT, Vijay-Kumar M. Adaptive Immunity Induces Tolerance to Flagellin by Attenuating TLR5 and NLRC4-Mediated Innate Immune Responses. Front Cell Infect Microbiol 2019; 9:29. [PMID: 30838179 PMCID: PMC6390806 DOI: 10.3389/fcimb.2019.00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/31/2019] [Indexed: 12/02/2022] Open
Abstract
The host immune system is constantly exposed to diverse microbial ligands, including flagellin (FliC; a ligand for TLR5 and NLRC4) and lipopolysaccharide (LPS; a ligand for TLR4), which could induce immune tolerance to subsequent exposure. Herein, we investigated the extent to which FliC induces self-tolerance in vivo and the role of adaptive immunity in mediating such effect. Mice pre-treated with FliC displayed attenuated serum keratinocyte-derived chemokine (KC), interleukin (IL)-6 and IL-18 responses to secondary challenge of FliC. A negative correlation was observed between high anti-FliC titer and reduced KC, IL-6, and IL-18 responses upon FliC re-challenge in WT mice, but not Rag1KO mice, suggesting that adaptive immunity could tolerize TLR5 and NLRC4. However, administration of LPS during FliC pre-treatment impaired the generation of anti-FliC antibodies and resulted in a partial loss of self-tolerance to FliC re-challenge. These findings may be relevant in the context of bacterial infection, as we observed that anti-FliC response are protective against systemic infection by Salmonella typhimurium. Taken together, our study delineates a distinct co-operative and reciprocal interaction between the innate and adaptive arms of immunity in modulating their responses to a bacterial protein.
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Affiliation(s)
- Beng San Yeoh
- Graduate Program in Immunology and Infectious Disease, Pennsylvania State University, University Park, PA, United States
| | - Andrew T Gewirtz
- Center for Inflammation, Immunity and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
| | - Matam Vijay-Kumar
- Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.,Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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131
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Broz P. Recognition of Intracellular Bacteria by Inflammasomes. Microbiol Spectr 2019; 7:10.1128/microbiolspec.bai-0003-2019. [PMID: 30848231 PMCID: PMC11588290 DOI: 10.1128/microbiolspec.bai-0003-2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Indexed: 01/08/2023] Open
Abstract
Inflammasomes are multiprotein signaling complexes that are assembled by cytosolic sensors upon the detection of infectious or noxious stimuli. These complexes activate inflammatory caspases to induce host cell death and cytokine secretion and are an essential part of antimicrobial host defense. In this review, I discuss how intracellular bacteria are detected by inflammasomes, how the specific sensing mechanism of each inflammasome receptor restricts the ability of bacteria to evade immune recognition, and how host cell death is used to control bacterial replication in vivo.
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Affiliation(s)
- Petr Broz
- Department of Biochemistry, University of Lausanne, Switzerland
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132
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Nambayan RJT, Sandin SI, Quint DA, Satyadi DM, de Alba E. The inflammasome adapter ASC assembles into filaments with integral participation of its two Death Domains, PYD and CARD. J Biol Chem 2019; 294:439-452. [PMID: 30459235 PMCID: PMC6333874 DOI: 10.1074/jbc.ra118.004407] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 11/17/2018] [Indexed: 11/06/2022] Open
Abstract
The inflammasome is a multiprotein complex necessary for the onset of inflammation. The adapter protein ASC assembles inflammasome components by acting as a molecular glue between danger-signal sensors and procaspase-1. The assembly is mediated by ASC self-association and protein interactions via its two Death Domains, PYD and CARD. Truncated versions of ASC have been shown to form filaments, but information on the filaments formed by full-length ASC is needed to construct a meaningful model of inflammasome assembly. To gain insights into this system, we used a combination of transmission EM, NMR, and computational analysis to investigate intact ASC structures. We show that ASC forms ∼6-7-nm-wide filaments that stack laterally to form bundles. The structural characteristics and dimensions of the bundles indicate that both PYD and CARD are integral parts of the filament. A truncated version of ASC with only the CARD domain (ASCCARD) forms different filaments (∼3-4-nm width), providing further evidence that both domains work in concert in filament assembly. Ring-shaped protein particles bound to pre-existing filaments match the size of ASC dimer structures generated by NMR-based protein docking, suggesting that the ASC dimer could be a basic building block for filament formation. Solution NMR binding studies identified the protein surfaces involved in the ASCCARD-ASCCARD interaction. These data provide new insights into the structural underpinnings of the inflammasome and should inform future efforts to interrogate this important biological system.
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Affiliation(s)
| | - Suzanne I Sandin
- From the Department of Bioengineering
- Chemistry and Chemical Biology Graduate Program
| | - David A Quint
- NSF-CREST Center for Cellular and Biomolecular Machines, and
- Department of Physics, University of California, Merced, California 95343
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133
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Abstract
Infection of C57BL/6 mice with wild-type Legionella pneumophila typically results in very mild disease. However, in mice where the cytosolic recognition of flagellin is impaired by mutation, L. pneumophila infection results in more severe lung inflammation that is reminiscent of Legionnaires' disease. This can be replicated in wild-type mice by using aflagellated mutants of L. pneumophila. These models greatly facilitate the investigation of L. pneumophila virulence factors and the complex pulmonary immune system that is triggered by infection. Here we describe methods for infecting C57BL/6 mice with aflagellated L. pneumophila, the quantification of bacterial load in the lungs and isolation and analysis of invading immune cells. These assays enable the identification of phagocyte subsets and can determine whether phagocytic cells act as a replicative niche for L. pneumophila replication.
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134
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Abstract
Legionella pneumophila is a gram-negative bacterium that infects many species of unicellular protozoa in freshwater environments. The human infection is accidental, and the bacteria may not have evolved strategies to bypass innate immune signaling in mammalian macrophages. Thus, L. pneumophila triggers many innate immune pathways including inflammasome activation. The inflammasomes are multimolecular platforms assembled in the host cell cytoplasm and lead to activation of inflammatory caspases. Inflammasome activation leads to secretion of inflammatory cytokines, such as IL-1β and IL-18, and an inflammatory form of cell death called pyroptosis, which initiates with the induction of a pore in the macrophage membranes. In this chapter we provide detailed protocols to evaluate Legionella-induced inflammasome activation in macrophages, including real-time pore formation assay, western blotting to detect activation of inflammatory caspases (cleavage and pulldown), and the measurement of inflammatory cytokines.
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Affiliation(s)
- Danielle P A Mascarenhas
- Department of Cell Biology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Dario S Zamboni
- Department of Cell Biology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
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135
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Structural Biology of NOD-Like Receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1172:119-141. [DOI: 10.1007/978-981-13-9367-9_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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136
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Maharana J, Panda D, De S. Deciphering the ATP-binding mechanism(s) in NLRP-NACHT 3D models using structural bioinformatics approaches. PLoS One 2018; 13:e0209420. [PMID: 30571723 PMCID: PMC6301626 DOI: 10.1371/journal.pone.0209420] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 12/05/2018] [Indexed: 01/04/2023] Open
Abstract
Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs), the first line of defense, are the cytosolic pattern recognition receptors (PRRs) that regulate the inflammatory activity in response to invading pathogens. NLRs are the members of AAA+ ATPase superfamily that comprises of N-terminal EBD(s), a centrally positioned NOD/NACHT and varying range of LRRs towards the C-terminal end. Due to the lack of structural data, the functional aspects of NLRP-signaling mechanism, which includes pathogen recognition, nucleotide-binding, and sensor-adaptor-effector interactions, are not fully understood. In this study, we implemented structural bioinformatics approaches including protein modeling, docking, and molecular dynamics simulations to explore the structural-dynamic features of ADP-/ATP-Mg2+ binding in NLRPNACHT models. Our results indicate a similar mode of ATP-Mg2+ binding in all NLRPNACHT models and the interacting residues are found consistent with reported mutagenesis data. Accompanied by the key amino acids (proposed to be crucial for ATP-Mg2+ coordination), we further have noticed that some additional conserved residues (including 'Trp' of the PhhCW motif, and 'Phe' and 'Tyr' of the GFxxxxRxxYF motif) are potentially interacting with ATP during dynamics; which require further experimentation for legitimacy. Overall, this study will help in understanding the ADP-/ATP-Mg2+ binding mechanisms in NLRPs in a broader perspective and the proposed ATP-binding pocket will aid in designing novel inhibitors for the regulation of inflammasome activity.
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Affiliation(s)
- Jitendra Maharana
- Department of Bioinformatics, Orissa University of Agriculture and Technology, Bhubaneswar, Odisha, India
- * E-mail: (JM); (SD)
| | - Debashis Panda
- Distributed Information Centre (DIC), Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
| | - Sachinandan De
- Animal Genomics Lab., Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
- * E-mail: (JM); (SD)
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137
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Hafner-Bratkovič I, Sušjan P, Lainšček D, Tapia-Abellán A, Cerović K, Kadunc L, Angosto-Bazarra D, Pelegrin P, Jerala R. NLRP3 lacking the leucine-rich repeat domain can be fully activated via the canonical inflammasome pathway. Nat Commun 2018; 9:5182. [PMID: 30518920 PMCID: PMC6281599 DOI: 10.1038/s41467-018-07573-4] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 11/08/2018] [Indexed: 11/23/2022] Open
Abstract
NLRP3 is a cytosolic sensor triggered by different pathogen- and self-derived signals that plays a central role in a variety of pathological conditions, including sterile inflammation. The leucine-rich repeat domain is present in several innate immune receptors, where it is frequently responsible for sensing danger signals and regulation of activation. Here we show by reconstitution of truncated and chimeric variants into Nlrp3−/− macrophages that the leucine-rich repeat domain is dispensable for activation and self-regulation of NLRP3 by several different triggers. The pyrin domain on the other hand is required to maintain NLRP3 in the inactive conformation. A fully responsive minimal NLRP3 truncation variant reconstitutes peritonitis in Nlrp3−/− mice. We demonstrate that in contrast to pathogen-activated NLRC4, the constitutively active NLRP3 molecule cannot engage wild-type NLRP3 molecules in a self-catalytic oligomerization. This lack of signal amplification is likely a protective mechanism to decrease sensitivity to endogenous triggers to impede autoinflammation. Activation of the NLRP3 inflammasome is associated with various diseases but its activation mechanism is not fully understood. Here, the authors determine the impact of different NLRP3 domains on sensing NLRP3 triggers, inflammasome assembly and regulation of NLRP3 inflammasome activation.
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Affiliation(s)
- Iva Hafner-Bratkovič
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia. .,EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, 1000, Ljubljana, Slovenia.
| | - Petra Sušjan
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Duško Lainšček
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Ana Tapia-Abellán
- Molecular Inflammation Group, Biomedical Research Institute of Murcia (IMIB-Arrixaca), University Clinical Hospital Virgen de la Arrixaca, Carretera Buenavista s/n, 30120 El Palmar, Murcia, Spain
| | - Kosta Cerović
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Lucija Kadunc
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Diego Angosto-Bazarra
- Molecular Inflammation Group, Biomedical Research Institute of Murcia (IMIB-Arrixaca), University Clinical Hospital Virgen de la Arrixaca, Carretera Buenavista s/n, 30120 El Palmar, Murcia, Spain
| | - Pablo Pelegrin
- Molecular Inflammation Group, Biomedical Research Institute of Murcia (IMIB-Arrixaca), University Clinical Hospital Virgen de la Arrixaca, Carretera Buenavista s/n, 30120 El Palmar, Murcia, Spain
| | - Roman Jerala
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia. .,EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, 1000, Ljubljana, Slovenia.
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138
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Bentham AR, Zdrzałek R, De la Concepcion JC, Banfield MJ. Uncoiling CNLs: Structure/Function Approaches to Understanding CC Domain Function in Plant NLRs. PLANT & CELL PHYSIOLOGY 2018; 59:2398-2408. [PMID: 30192967 PMCID: PMC6290485 DOI: 10.1093/pcp/pcy185] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 08/24/2018] [Indexed: 05/20/2023]
Abstract
Plant nucleotide-binding leucine-rich repeat receptors (NLRs) are intracellular pathogen receptors whose N-terminal domains are integral to signal transduction after perception of a pathogen-derived effector protein. The two major plant NLR classes are defined by the presence of either a Toll/interleukin-1 receptor (TIR) or a coiled-coil (CC) domain at their N-terminus (TNLs and CNLs). Our knowledge of how CC domains function in plant CNLs lags behind that of how TIR domains function in plant TNLs. CNLs are the most abundant class of NLRs in monocotyledonous plants, and further research is required to understand the molecular mechanisms of how these domains contribute to disease resistance in cereal crops. Previous studies of CC domains have revealed functional diversity, making categorization difficult, which in turn makes experimental design for assaying function challenging. In this review, we summarize the current understanding of CC domain function in plant CNLs, highlighting the differences in modes of action and structure. To aid experimental design in exploring CC domain function, we present a 'best-practice' guide to designing constructs through use of sequence and secondary structure comparisons and discuss the relevant assays for investigating CC domain function. Finally, we discuss whether using homology modeling is useful to describe putative CC domain function in CNLs through parallels with the functions of previously characterized helical adaptor proteins.
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Affiliation(s)
- Adam R Bentham
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, UK
| | - Rafał Zdrzałek
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, UK
| | | | - Mark J Banfield
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, UK
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139
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Thomson NM, Ferreira JL, Matthews-Palmer TR, Beeby M, Pallen MJ. Giant flagellins form thick flagellar filaments in two species of marine γ-proteobacteria. PLoS One 2018; 13:e0206544. [PMID: 30462661 PMCID: PMC6248924 DOI: 10.1371/journal.pone.0206544] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/15/2018] [Indexed: 01/04/2023] Open
Abstract
Flagella, the primary means of motility in bacteria, are helical filaments that function as microscopic propellers composed of thousands of copies of the protein flagellin. Here, we show that many bacteria encode “giant” flagellins, greater than a thousand amino acids in length, and that two species that encode giant flagellins, the marine γ-proteobacteria Bermanella marisrubri and Oleibacter marinus, produce monopolar flagellar filaments considerably thicker than filaments composed of shorter flagellin monomers. We confirm that the flagellum from B. marisrubri is built from its giant flagellin. Phylogenetic analysis reveals that the mechanism of evolution of giant flagellins has followed a stepwise process involving an internal domain duplication followed by insertion of an additional novel insert. This work illustrates how “the” bacterial flagellum should not be seen as a single, idealised structure, but as a continuum of evolved machines adapted to a range of niches.
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Affiliation(s)
| | - Josie L. Ferreira
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail:
| | - Mark J. Pallen
- Quadram Institute, Norwich Research Park, Norwich, Norfolk, United Kingdom
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140
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Qi T, Seong K, Thomazella DPT, Kim JR, Pham J, Seo E, Cho MJ, Schultink A, Staskawicz BJ. NRG1 functions downstream of EDS1 to regulate TIR-NLR-mediated plant immunity in Nicotiana benthamiana. Proc Natl Acad Sci U S A 2018; 115:E10979-E10987. [PMID: 30373842 PMCID: PMC6243234 DOI: 10.1073/pnas.1814856115] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Effector-triggered immunity (ETI) in plants involves a large family of nucleotide-binding leucine-rich repeat (NLR) immune receptors, including Toll/IL-1 receptor-NLRs (TNLs) and coiled-coil NLRs (CNLs). Although various NLR immune receptors are known, a mechanistic understanding of NLR function in ETI remains unclear. The TNL Recognition of XopQ 1 (Roq1) recognizes the effectors XopQ and HopQ1 from Xanthomonas and Pseudomonas, respectively, which activates resistance to Xanthomonas euvesicatoria and Xanthomonas gardneri in an Enhanced Disease Susceptibility 1 (EDS1)-dependent way in Nicotiana benthamiana In this study, we found that the N. benthamiana N requirement gene 1 (NRG1), a CNL protein required for the tobacco TNL protein N-mediated resistance to tobacco mosaic virus, is also essential for immune signaling [including hypersensitive response (HR)] triggered by the TNLs Roq1 and Recognition of Peronospora parasitica 1 (RPP1), but not by the CNLs Bs2 and Rps2, suggesting that NRG1 may be a conserved key component in TNL signaling pathways. Besides EDS1, Roq1 and NRG1 are necessary for resistance to Xanthomonas and Pseudomonas in N. benthamiana NRG1 functions downstream of Roq1 and EDS1 and physically associates with EDS1 in mediating XopQ-Roq1-triggered immunity. Moreover, RNA sequencing analysis showed that XopQ-triggered gene-expression profile changes in N. benthamiana were almost entirely mediated by Roq1 and EDS1 and were largely regulated by NRG1. Overall, our study demonstrates that NRG1 is a key component that acts downstream of EDS1 to mediate various TNL signaling pathways, including Roq1 and RPP1-mediated HR, resistance to Xanthomonas and Pseudomonas, and XopQ-regulated transcriptional changes in N. benthamiana.
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Affiliation(s)
- Tiancong Qi
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Kyungyong Seong
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Daniela P T Thomazella
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Joonyoung Ryan Kim
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Julie Pham
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
| | - Eunyoung Seo
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Myeong-Je Cho
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
| | - Alex Schultink
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
| | - Brian J Staskawicz
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120;
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
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141
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Matyszewski M, Zheng W, Lueck J, Antiochos B, Egelman EH, Sohn J. Cryo-EM structure of the NLRC4 CARD filament provides insights into how symmetric and asymmetric supramolecular structures drive inflammasome assembly. J Biol Chem 2018; 293:20240-20248. [PMID: 30385506 DOI: 10.1074/jbc.ra118.006050] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 10/26/2018] [Indexed: 01/12/2023] Open
Abstract
Inflammasomes are supramolecular signaling platforms integral to innate immune defense against invading pathogens. The NOD-like receptor (NLR) family apoptosis inhibitory protein (NAIP)·NLR family caspase-recruiting domain (CARD) domain-containing 4 (NLRC4) inflammasome recognizes intracellular bacteria and induces the polymerization of the caspase-1 protease, which in turn executes maturation of interleukin-1β (IL-1β) and pyroptosis. Several high-resolution structures of the fully assembled NAIP·NLRC4 complex are available, but these structures do not resolve the architecture of the CARD filament in atomic detail. Here, we present the cryo-EM structure of the filament assembled by the CARD of human NLRC4 (NLRC4CARD) at 3.4 Å resolution. The structure revealed that the helical architecture of the NLRC4CARD filament is essentially identical to that of the downstream filament assembled by the CARD of caspase-1 (casp1CARD), but deviates from the split washer-like assembly of the NAIP·NLRC4 oligomer. Our results suggest that architectural complementarity is a major driver for the recognition between upstream and downstream CARD assemblies in inflammasomes. Furthermore, a Monte Carlo simulation of the NLRC4CARD filament assembly rationalized why an (un)decameric NLRC4 oligomer is optimal for assembling the helical base of the NLRC4CARD filament. Together, our results explain how symmetric and asymmetric supramolecular assemblies enable high-fidelity signaling in inflammasomes.
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Affiliation(s)
- Mariusz Matyszewski
- From the Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Weili Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, and
| | - Jacob Lueck
- From the Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Brendan Antiochos
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, and.
| | - Jungsan Sohn
- From the Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205,.
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142
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Li Y, Fu TM, Lu A, Witt K, Ruan J, Shen C, Wu H. Cryo-EM structures of ASC and NLRC4 CARD filaments reveal a unified mechanism of nucleation and activation of caspase-1. Proc Natl Acad Sci U S A 2018; 115:10845-10852. [PMID: 30279182 PMCID: PMC6205419 DOI: 10.1073/pnas.1810524115] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Canonical inflammasomes are cytosolic supramolecular complexes that activate caspase-1 upon sensing extrinsic microbial invasions and intrinsic sterile stress signals. During inflammasome assembly, adaptor proteins ASC and NLRC4 recruit caspase-1 through homotypic caspase recruitment domain (CARD) interactions, leading to caspase-1 dimerization and activation. Activated caspase-1 processes proinflammatory cytokines and Gasdermin D to induce cytokine maturation and pyroptotic cell death. Here, we present cryo-electron microscopy (cryo-EM) structures of NLRC4 CARD and ASC CARD filaments mediated by conserved three types of asymmetric interactions (types I, II, and III). We find that the CARDs of these two adaptor proteins share a similar assembly pattern, which matches that of the caspase-1 CARD filament whose structure we defined previously. These data indicate a unified mechanism for downstream caspase-1 recruitment through CARD-CARD interactions by both adaptors. Using structure modeling, we further show that full-length NLRC4 assembles via two separate symmetries at its CARD and its nucleotide-binding domain (NBD), respectively.
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Affiliation(s)
- Yang Li
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Tian-Min Fu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115;
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Alvin Lu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Kristen Witt
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Jianbin Ruan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Chen Shen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115;
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
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143
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Cytosolic Recognition of Microbes and Pathogens: Inflammasomes in Action. Microbiol Mol Biol Rev 2018; 82:82/4/e00015-18. [PMID: 30209070 DOI: 10.1128/mmbr.00015-18] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Infection is a dynamic biological process underpinned by a complex interplay between the pathogen and the host. Microbes from all domains of life, including bacteria, viruses, fungi, and protozoan parasites, have the capacity to cause infection. Infection is sensed by the host, which often leads to activation of the inflammasome, a cytosolic macromolecular signaling platform that mediates the release of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18 and cleavage of the pore-forming protein gasdermin D, leading to pyroptosis. Host-mediated sensing of the infection occurs when pathogens inject or carry pathogen-associated molecular patterns (PAMPs) into the cytoplasm or induce damage that causes cytosolic liberation of danger-associated molecular patterns (DAMPs) in the host cell. Recognition of PAMPs and DAMPs by inflammasome sensors, including NLRP1, NLRP3, NLRC4, NAIP, AIM2, and Pyrin, initiates a cascade of events that culminate in inflammation and cell death. However, pathogens can deploy virulence factors capable of minimizing or evading host detection. This review presents a comprehensive overview of the mechanisms of microbe-induced activation of the inflammasome and the functional consequences of inflammasome activation in infectious diseases. We also explore the microbial strategies used in the evasion of inflammasome sensing at the host-microbe interaction interface.
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144
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Nanson JD, Rahaman MH, Ve T, Kobe B. Regulation of signaling by cooperative assembly formation in mammalian innate immunity signalosomes by molecular mimics. Semin Cell Dev Biol 2018; 99:96-114. [PMID: 29738879 DOI: 10.1016/j.semcdb.2018.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/18/2018] [Accepted: 05/04/2018] [Indexed: 12/16/2022]
Abstract
Innate immunity pathways constitute the first line of defense against infections and cellular damage. An emerging concept in these pathways is that signaling involves the formation of finite (e.g. rings in NLRs) or open-ended higher-order assemblies (e.g. filamentous assemblies by members of the death-fold family and TIR domains). This signaling by cooperative assembly formation (SCAF) mechanism allows rapid and strongly amplified responses to minute amounts of stimulus. While the characterization of the molecular mechanisms of SCAF has seen rapid progress, little is known about its regulation. One emerging theme involves proteins produced both in host cells and by pathogens that appear to mimic the signaling components. Recently characterized examples involve the capping of the filamentous assemblies formed by caspase-1 CARDs by the CARD-only protein INCA, and those formed by caspase-8 by the DED-containing protein MC159. By contrast, the CARD-only protein ICEBERG and the DED-containing protein cFLIP incorporate into signaling filaments and presumably interfere with proximity based activation of caspases. We review selected examples of SCAF in innate immunity pathways and focus on the current knowledge on signaling component mimics produced by mammalian and pathogen cells and what is known about their mechanisms of action.
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Affiliation(s)
- Jeffrey D Nanson
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Md Habibur Rahaman
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Thomas Ve
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia; Institute for Glycomics, Griffith University, Southport, QLD, 4222, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia.
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145
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Moghaddas F, Zeng P, Zhang Y, Schützle H, Brenner S, Hofmann SR, Berner R, Zhao Y, Lu B, Chen X, Zhang L, Cheng S, Winkler S, Lehmberg K, Canna SW, Czabotar PE, Wicks IP, De Nardo D, Hedrich CM, Zeng H, Masters SL. Autoinflammatory mutation in NLRC4 reveals a leucine-rich repeat (LRR)-LRR oligomerization interface. J Allergy Clin Immunol 2018; 142:1956-1967.e6. [PMID: 29778503 PMCID: PMC6281029 DOI: 10.1016/j.jaci.2018.04.033] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/22/2018] [Accepted: 04/27/2018] [Indexed: 12/28/2022]
Abstract
Background Monogenic autoinflammatory disorders are characterized by dysregulation of the innate immune system, for example by gain-of-function mutations in inflammasome-forming proteins, such as NOD-like receptor family CARD-containing 4 protein (NLRC4). Objective Here we investigate the mechanism by which a novel mutation in the leucine-rich repeat (LRR) domain of NLRC4 (c.G1965C, p.W655C) contributes to autoinflammatory disease. Methods: We studied 2 unrelated patients with early-onset macrophage activation syndrome harboring the same de novo mutation in NLRC4. In vitro inflammasome complex formation was quantified by using flow cytometric analysis of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) specks. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 techniques and lentiviral transduction were used to generate THP-1 cells with either wild-type or mutant NLRC4 cDNA. Cell death and release of IL-1β/IL-18 were quantified by using flow cytometry and ELISA, respectively. Results The p.W655C NLRC4 mutation caused increased ASC speck formation, caspase-1–dependent cell death, and IL-1β/IL-18 production. ASC contributed to p.W655C NLRC4–mediated cytokine release but not cell death. Mutation of p.W655 activated the NLRC4 inflammasome complex by engaging with 2 interfaces on the opposing LRR domain of the oligomer. One key set of residues (p.D1010, p.D1011, p.L1012, and p.I1015) participated in LRR-LRR oligomerization when triggered by mutant NLRC4 or type 3 secretion system effector (PrgI) stimulation of the NLRC4 inflammasome complex. Conclusion This is the first report of a mutation in the LRR domain of NLRC4 causing autoinflammatory disease. c.G1965C/p.W655C NLRC4 increased inflammasome activation in vitro. Data generated from various NLRC4 mutations provides evidence that the LRR-LRR interface has an important and previously unrecognized role in oligomerization of the NLRC4 inflammasome complex.
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Affiliation(s)
- Fiona Moghaddas
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Ping Zeng
- Department of Rheumatology, Guangzhou Women and Children's Medical Centre, Guangzhou, China
| | - Yuxia Zhang
- Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou, China
| | - Heike Schützle
- Department of Pediatrics, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Sebastian Brenner
- Department of Pediatrics, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Sigrun R Hofmann
- Department of Pediatrics, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Reinhard Berner
- Department of Pediatrics, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Yuanbo Zhao
- Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou, China; Department of Chemical Biology, Guizhou Medical University, Guiyang, China
| | - Bingtai Lu
- Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou, China
| | - Xiaoyun Chen
- Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou, China
| | - Li Zhang
- Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou, China
| | - Suyun Cheng
- Department of Rheumatology, Guangzhou Women and Children's Medical Centre, Guangzhou, China
| | - Stefan Winkler
- Department of Pediatrics, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Kai Lehmberg
- Division of Pediatric Stem Cell Transplantation and Immunology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Scott W Canna
- Pediatric Rheumatology/RK Mellon Institute, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pa
| | - Peter E Czabotar
- Department of Medical Biology, University of Melbourne, Parkville, Australia; Structural Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Ian P Wicks
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia; Rheumatology Department, Royal Melbourne Hospital, Parkville, Australia
| | - Dominic De Nardo
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Christian M Hedrich
- Department of Pediatrics, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany; Department of Women's & Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom; Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust Hospital, Liverpool, United Kingdom
| | - Huasong Zeng
- Department of Rheumatology, Guangzhou Women and Children's Medical Centre, Guangzhou, China
| | - Seth L Masters
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia; Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou, China.
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146
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Indispensable Role of Proteases in Plant Innate Immunity. Int J Mol Sci 2018; 19:ijms19020629. [PMID: 29473858 PMCID: PMC5855851 DOI: 10.3390/ijms19020629] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 02/14/2018] [Accepted: 02/19/2018] [Indexed: 12/13/2022] Open
Abstract
Plant defense is achieved mainly through the induction of microbe-associated molecular patterns (MAMP)-triggered immunity (MTI), effector-triggered immunity (ETI), systemic acquired resistance (SAR), induced systemic resistance (ISR), and RNA silencing. Plant immunity is a highly complex phenomenon with its own unique features that have emerged as a result of the arms race between plants and pathogens. However, the regulation of these processes is the same for all living organisms, including plants, and is controlled by proteases. Different families of plant proteases are involved in every type of immunity: some of the proteases that are covered in this review participate in MTI, affecting stomatal closure and callose deposition. A large number of proteases act in the apoplast, contributing to ETI by managing extracellular defense. A vast majority of the endogenous proteases discussed in this review are associated with the programmed cell death (PCD) of the infected cells and exhibit caspase-like activities. The synthesis of signal molecules, such as salicylic acid, jasmonic acid, and ethylene, and their signaling pathways, are regulated by endogenous proteases that affect the induction of pathogenesis-related genes and SAR or ISR establishment. A number of proteases are associated with herbivore defense. In this review, we summarize the data concerning identified plant endogenous proteases, their effect on plant-pathogen interactions, their subcellular localization, and their functional properties, if available, and we attribute a role in the different types and stages of innate immunity for each of the proteases covered.
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147
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Rathinam VAK, Chan FKM. Inflammasome, Inflammation, and Tissue Homeostasis. Trends Mol Med 2018; 24:304-318. [PMID: 29433944 DOI: 10.1016/j.molmed.2018.01.004] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/06/2018] [Accepted: 01/14/2018] [Indexed: 02/07/2023]
Abstract
Organismal fitness demands proper response to neutralize the threat from infection or injury. At the mammalian intestinal epithelium barrier, the inflammasome coordinates an elaborate tissue repair response marked by the induction of antimicrobial peptides, wound-healing cytokines, and reparative proliferation of epithelial stem cells. The inflammasome in myeloid and intestinal epithelial compartments exerts these effects in part through maintenance of a healthy microbiota. Disease-associated mutations and elevated expression of certain inflammasome sensors have been identified. In many cases, inhibition of inflammasome activity has dramatic effects on disease outcome in mouse models of experimental colitis. Here, we discuss recent studies on the role of distinct inflammasome sensors in intestinal homeostasis and how this knowledge may be translated into a therapeutic setting.
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Affiliation(s)
- Vijay A K Rathinam
- Department of Immunology, UConn Health School of Medicine, Farmington, CT 06030, USA.
| | - Francis Ka-Ming Chan
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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148
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Poudel B, Gurung P. An update on cell intrinsic negative regulators of the NLRP3 inflammasome. J Leukoc Biol 2018; 103:10.1002/JLB.3MIR0917-350R. [PMID: 29377242 PMCID: PMC6202258 DOI: 10.1002/jlb.3mir0917-350r] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/09/2018] [Indexed: 12/22/2022] Open
Abstract
Inflammasomes are multimeric protein complexes that promote inflammation (through specific cleavage and production of bioactive IL-1β and IL-18) and pyroptotic cell death. The central role of inflammasomes in combating infection and maintaining homeostasis has been studied extensively. Although inflammasome-mediated inflammation and cell death are vital to limit pathogenic insults and to promote wound healing/tissue regeneration, unchecked/uncontrolled inflammation, and cell death can cause cytokine storm, tissue damage, autoinflammatory and autoimmune diseases, and even death in the afflicted individuals. NLRP3 is one of the major cytosolic sensors that assemble an inflammasome. Given the adverse consequences of uncontrolled inflammasome activation, our immune system has developed tiered mechanisms to inhibit NLRP3 inflammasome activation. In this review, we highlight and discuss recent advances and our current understanding of mechanisms by which NLRP3 inflammasome can be negatively regulated.
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Affiliation(s)
- Barun Poudel
- Inflammation Program, University of Iowa, Iowa City, Iowa, USA
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Prajwal Gurung
- Inflammation Program, University of Iowa, Iowa City, Iowa, USA
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
- Immunology Graduate Program, University of Iowa, Iowa City, Iowa, USA
- Center for Immunology and Immune-Based Disease, University of Iowa, Iowa City, Iowa, USA
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149
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Abstract
Activation of the NAIP/NLRC4 inflammasomes initiates inflammatory responses against bacterial invasion. Two recent reports described the cryo-EM structure of the flagellin/NAIP5 complex, providing important insights into the mechanism of bacterial sensing by innate immunity.
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Affiliation(s)
- Liman Zhang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
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150
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VanHook AM. Paper of note in
Science
358
(6365). Sci Signal 2017. [DOI: 10.1126/scisignal.aar5178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This week’s article presents the structure of the NLRC4 inflammasome bound to ligand.
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