151
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Martin SJ. The FEBS Journal in 2016: read, reflect and don't feed the wolves. FEBS J 2015; 283:4-8. [PMID: 26662635 DOI: 10.1111/febs.13623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Seamus Martin holds the Smurfit Chair of Medical Genetics at the Smurfit Institute of Genetics, Trinity College Dublin, Ireland. He obtained his PhD with Tom Cotter at the National University of Ireland, followed by post-doctoral fellowships with Ivan Roitt at UCL, London, UK, and Doug Green at The La Jolla Institute for Allergy and Immunology, California, USA. He works on all aspects of cell death control and is especially interested in the links between apoptosis, necrosis and inflammation. He received the GlaxoSmithKline Award of The Biochemical Society for his work on unravelling the caspase activation cascade and was elected to the Royal Irish Academy in 2006 and EMBO in 2009. He has been the Editor-in-Chief of The FEBS Journal since 2014.
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Affiliation(s)
- Seamus J Martin
- The FEBS Journal Editorial Office, Cambridge, UK.,Department of Genetics, Trinity College, Dublin 2, Ireland
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152
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Diebolder CA, Halff EF, Koster AJ, Huizinga EG, Koning RI. Cryoelectron Tomography of the NAIP5/NLRC4 Inflammasome: Implications for NLR Activation. Structure 2015; 23:2349-2357. [PMID: 26585513 DOI: 10.1016/j.str.2015.10.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 09/24/2015] [Accepted: 10/01/2015] [Indexed: 10/22/2022]
Abstract
Inflammasomes are high molecular weight protein complexes that play a crucial role in innate immunity by activating caspase-1. Inflammasome formation is initiated when molecules originating from invading microorganisms activate nucleotide-binding domain and leucine-rich repeat-containing receptors (NLRs) and induce NLR multimerization. Little is known about the conformational changes involved in NLR activation and the structural organization of NLR multimers. Here, we show by cryoelectron tomography that flagellin-induced NAIP5/NLRC4 multimers form right- and left-handed helical polymers with a diameter of 28 nm and a pitch of 6.5 nm. Subtomogram averaging produced an electron density map at 4 nm resolution, which was used for rigid body fitting of NLR subdomains derived from the crystal structure of dormant NLRC4. The resulting structural model of inflammasome-incorporated NLRC4 indicates that a prominent rotation of the LRR domain of NLRC4 is necessary for multimer formation, providing unprecedented insight into the conformational changes that accompany NLR activation.
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Affiliation(s)
- Christoph A Diebolder
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, the Netherlands; Crystal and Structural Chemistry, Department of Chemistry, Faculty of Science, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Els F Halff
- Crystal and Structural Chemistry, Department of Chemistry, Faculty of Science, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Abraham J Koster
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, the Netherlands
| | - Eric G Huizinga
- Crystal and Structural Chemistry, Department of Chemistry, Faculty of Science, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Roman I Koning
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, the Netherlands.
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153
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Jank T, Belyi Y, Aktories K. Bacterial glycosyltransferase toxins. Cell Microbiol 2015; 17:1752-65. [DOI: 10.1111/cmi.12533] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 12/28/2022]
Affiliation(s)
- Thomas Jank
- Institute for Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs University of Freiburg; Freiburg Germany
| | - Yury Belyi
- Gamaleya Research Institute; Moscow 123098 Russia
- Freiburg Institute for Advanced Studies (FRIAS); Albert-Ludwigs University of Freiburg; Freiburg Germany
| | - Klaus Aktories
- Institute for Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs University of Freiburg; Freiburg Germany
- Freiburg Institute for Advanced Studies (FRIAS); Albert-Ludwigs University of Freiburg; Freiburg Germany
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154
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Vajjhala PR, Lu A, Brown DL, Pang SW, Sagulenko V, Sester DP, Cridland SO, Hill JM, Schroder K, Stow JL, Wu H, Stacey KJ. The Inflammasome Adaptor ASC Induces Procaspase-8 Death Effector Domain Filaments. J Biol Chem 2015; 290:29217-30. [PMID: 26468282 DOI: 10.1074/jbc.m115.687731] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Indexed: 01/19/2023] Open
Abstract
Inflammasomes mediate inflammatory and cell death responses to pathogens and cellular stress signals via activation of procaspases-1 and -8. During inflammasome assembly, activated receptors of the NLR or PYHIN family recruit the adaptor protein ASC and initiate polymerization of its pyrin domain (PYD) into filaments. We show that ASC filaments in turn nucleate procaspase-8 death effector domain (DED) filaments in vitro and in vivo. Interaction between ASC PYD and procaspase-8 tandem DEDs optimally required both DEDs and represents an unusual heterotypic interaction between domains of the death fold superfamily. Analysis of ASC PYD mutants showed that interaction surfaces that mediate procaspase-8 interaction overlap with those required for ASC self-association and interaction with the PYDs of inflammasome initiators. Our data indicate that multiple types of death fold domain filaments form at inflammasomes and that PYD/DED and homotypic PYD interaction modes are similar. Interestingly, we observed condensation of procaspase-8 filaments containing the catalytic domain, suggesting that procaspase-8 interactions within and/or between filaments may be involved in caspase-8 activation. Procaspase-8 filaments may also be relevant to apoptosis induced by death receptors.
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Affiliation(s)
| | - Alvin Lu
- the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, and the Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115
| | - Darren L Brown
- the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Siew Wai Pang
- From the School of Chemistry and Molecular Biosciences and
| | | | - David P Sester
- From the School of Chemistry and Molecular Biosciences and
| | | | - Justine M Hill
- From the School of Chemistry and Molecular Biosciences and
| | - Kate Schroder
- the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jennifer L Stow
- the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Hao Wu
- the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, and the Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115
| | - Katryn J Stacey
- From the School of Chemistry and Molecular Biosciences and the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia,
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155
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Structure and assembly of the mouse ASC inflammasome by combined NMR spectroscopy and cryo-electron microscopy. Proc Natl Acad Sci U S A 2015; 112:13237-42. [PMID: 26464513 DOI: 10.1073/pnas.1507579112] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Inflammasomes are multiprotein complexes that control the innate immune response by activating caspase-1, thus promoting the secretion of cytokines in response to invading pathogens and endogenous triggers. Assembly of inflammasomes is induced by activation of a receptor protein. Many inflammasome receptors require the adapter protein ASC [apoptosis-associated speck-like protein containing a caspase-recruitment domain (CARD)], which consists of two domains, the N-terminal pyrin domain (PYD) and the C-terminal CARD. Upon activation, ASC forms large oligomeric filaments, which facilitate procaspase-1 recruitment. Here, we characterize the structure and filament formation of mouse ASC in vitro at atomic resolution. Information from cryo-electron microscopy and solid-state NMR spectroscopy is combined in a single structure calculation to obtain the atomic-resolution structure of the ASC filament. Perturbations of NMR resonances upon filament formation monitor the specific binding interfaces of ASC-PYD association. Importantly, NMR experiments show the rigidity of the PYD forming the core of the filament as well as the high mobility of the CARD relative to this core. The findings are validated by structure-based mutagenesis experiments in cultured macrophages. The 3D structure of the mouse ASC-PYD filament is highly similar to the recently determined human ASC-PYD filament, suggesting evolutionary conservation of ASC-dependent inflammasome mechanisms.
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156
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Morrone SR, Matyszewski M, Yu X, Delannoy M, Egelman EH, Sohn J. Assembly-driven activation of the AIM2 foreign-dsDNA sensor provides a polymerization template for downstream ASC. Nat Commun 2015. [PMID: 26197926 PMCID: PMC4525163 DOI: 10.1038/ncomms8827] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
AIM2 recognizes foreign dsDNA and assembles into the inflammasome, a filamentous supramolecular signalling platform required to launch innate immune responses. We show here that the pyrin domain of AIM2 (AIM2PYD) drives both filament formation and dsDNA binding. In addition, the dsDNA-binding domain of AIM2 also oligomerizes and assists in filament formation. The ability to oligomerize is critical for binding dsDNA, and in turn permits the size of dsDNA to regulate the assembly of the AIM2 polymers. The AIM2PYD oligomers define the filamentous structure, and the helical symmetry of the AIM2PYD filament is consistent with the filament assembled by the PYD of the downstream adaptor ASC. Our results suggest that the role of AIM2PYD is not autoinhibitory, but generating a structural template by coupling ligand binding and oligomerization is a key signal transduction mechanism in the AIM2 inflammasome. The AIM2 inflammasome complex is essential for defence against a number of human pathogens but how it assembles upon recognition of foreign DNA remains incompletely understood. Here Morrone et al. suggest the AIM2 pyrin domain acts in both DNA binding and filament assembly to generate a structural template for complex assembly.
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Affiliation(s)
- Seamus R Morrone
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine Baltimore, Maryland 21205, USA
| | - Mariusz Matyszewski
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine Baltimore, Maryland 21205, USA
| | - Xiong Yu
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine Charlottesville, Virginia 22908, USA
| | - Michael Delannoy
- Microscope Core Facilities, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine Charlottesville, Virginia 22908, USA
| | - Jungsan Sohn
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine Baltimore, Maryland 21205, USA
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157
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Innate Immunity and Biomaterials at the Nexus: Friends or Foes. BIOMED RESEARCH INTERNATIONAL 2015; 2015:342304. [PMID: 26247017 PMCID: PMC4515263 DOI: 10.1155/2015/342304] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 06/15/2015] [Accepted: 06/22/2015] [Indexed: 01/04/2023]
Abstract
Biomaterial implants are an established part of medical practice, encompassing a broad range of devices that widely differ in function and structural composition. However, one common property amongst biomaterials is the induction of the foreign body response: an acute sterile inflammatory reaction which overlaps with tissue vascularisation and remodelling and ultimately fibrotic encapsulation of the biomaterial to prevent further interaction with host tissue. Severity and clinical manifestation of the biomaterial-induced foreign body response are different for each biomaterial, with cases of incompatibility often associated with loss of function. However, unravelling the mechanisms that progress to the formation of the fibrotic capsule highlights the tightly intertwined nature of immunological responses to a seemingly noncanonical “antigen.” In this review, we detail the pathways associated with the foreign body response and describe possible mechanisms of immune involvement that can be targeted. We also discuss methods of modulating the immune response by altering the physiochemical surface properties of the biomaterial prior to implantation. Developments in these areas are reliant on reproducible and effective animal models and may allow a “combined” immunomodulatory approach of adapting surface properties of biomaterials, as well as treating key immune pathways to ultimately reduce the negative consequences of biomaterial implantation.
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158
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Lu A, Li Y, Yin Q, Ruan J, Yu X, Egelman E, Wu H. Plasticity in PYD assembly revealed by cryo-EM structure of the PYD filament of AIM2. Cell Discov 2015; 1. [PMID: 26583071 PMCID: PMC4646227 DOI: 10.1038/celldisc.2015.13] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Absent in melanoma 2 (AIM2) is an essential cytosolic double-stranded DNA receptor that assembles with the adaptor, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and caspase-1 to form the AIM2 inflammasome, which leads to proteolytic maturation of cytokines and pyroptotic cell death. AIM2 contains an N-terminal Pyrin domain (PYD) that interacts with ASC through PYD/PYD interactions and nucleates ASCPYD filament formation. To elucidate the molecular basis of AIM2-induced ASCPYD polymerization, we generated AIM2PYD filaments fused to green fluorescent protein (GFP) and determined its cryo-electron microscopic (cryo-EM) structure. The map showed distinct definition of helices, allowing fitting of the crystal structure. Surprisingly, the GFP-AIM2PYD filament is a 1-start helix with helical parameters distinct from those of the 3-start ASCPYD filament. However, despite the apparent symmetry difference, helical net and detailed interface analyses reveal minimal changes in subunit packing. GFP-AIM2PYD nucleated ASCPYD filament formation in comparable efficiency as untagged AIM2PYD, suggesting assembly plasticity in both AIM2PYD and ASCPYD. The DNA-binding domain of AIM2 is able to form AIM2/DNA filaments, within which the AIM2PYD is brought into proximity to template ASCPYD filament assembly. Because ASC is able to interact with many PYD-containing receptors for the formation of inflammasomes, the observed structural plasticity may be critically important for this versatility in the PYD/PYD interactions.
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Affiliation(s)
- Alvin Lu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA ; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Yang Li
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA ; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Qian Yin
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA ; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Jianbin Ruan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA ; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Xiong Yu
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Edward Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA ; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
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159
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van der Burgh R, Boes M. Mitochondria in autoinflammation: cause, mediator or bystander? Trends Endocrinol Metab 2015; 26:263-71. [PMID: 25850613 DOI: 10.1016/j.tem.2015.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 03/06/2015] [Accepted: 03/13/2015] [Indexed: 12/19/2022]
Abstract
People suffering from autoinflammatory disease (AID) have recurring sterile inflammation due to dysregulated inflammasome activation. Although certain genes have been associated with several AIDs, the molecular underpinnings of seemingly spontaneous inflammation are not well understood. Emerging data now suggest that mitochondrial reactive oxygen species (ROS), mitochondrial DNA (mtDNA), and autophagy might drive key signaling pathways towards activation of the inflammasome. In this review, we discuss recent findings and highlight common features between different AIDs and mitochondrial (dys)function. Although it is still early to identify clear therapeutic targets, the emerging paradigms in inflammation and mitochondrial biology show that mitochondria play an important role in AIDs, and understanding this interplay will be key in the development of new therapies.
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Affiliation(s)
- Robert van der Burgh
- Department of Pediatric Immunology and Infectious Diseases and Laboratory of Translational Immunology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht EA, 3584, The Netherlands
| | - Marianne Boes
- Department of Pediatric Immunology and Infectious Diseases and Laboratory of Translational Immunology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht EA, 3584, The Netherlands.
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160
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Martin SJ. The FEBS Journalin 2015: onwards and upwards. FEBS J 2014. [DOI: 10.1111/febs.13164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Seamus J. Martin
- The FEBS Journal Editorial Office; Cambridge UK
- Department of Genetics; Trinity College; Dublin 2 Ireland
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