title: Inflammasome activation causes dual recruitment of NLRC4 and NLRP3 to the same macromolecular complex.
abstract: Pathogen recognition by nucleotide-binding oligomerization domain-like receptor (NLR) results in the formation of a macromolecular protein complex (inflammasome) that drives protective inflammatory responses in the host. It is thought that the number of inflammasome complexes forming in a cell is determined by the number of NLRs being activated, with each NLR initiating its own inflammasome assembly independent of one another; however, we show here that the important foodborne pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) simultaneously activates at least two NLRs, whereas only a single inflammasome complex is formed in a macrophage. Both nucleotide-binding domain and leucine-rich repeat caspase recruitment domain 4 and nucleotide-binding domain and leucine-rich repeat pyrin domain 3 are simultaneously present in the same inflammasome, where both NLRs are required to drive IL-1β processing within the Salmonella-infected cell and to regulate the bacterial burden in mice. Superresolution imaging of Salmonella-infected macrophages revealed a macromolecular complex with an outer ring of apoptosis-associated speck-like protein containing a caspase activation and recruitment domain and an inner ring of NLRs, with active caspase effectors containing the pro-IL-1β substrate localized internal to the ring structure. Our data reveal the spatial localization of different components of the inflammasome and how different members of the NLR family cooperate to drive robust IL-1β processing during Salmonella infection.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
authors.forename: Si Ming
authors.initials: SM
authors.lastname: Man
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Hopkins
authors.affiliation: Sector of Biological and Soft Systems, The Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom;
authors.forename: Eileen
authors.initials: E
authors.lastname: Nugent
authors.affiliation: Randall Division of Cell and Molecular Biophysics, Kings College, London WC2R 2LS, United Kingdom; and.
authors.forename: Susan
authors.initials: S
authors.lastname: Cox
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
authors.forename: Ivo M
authors.initials: IM
authors.lastname: Glück
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Tourlomousis
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
authors.forename: John A
authors.initials: JA
authors.lastname: Wright
authors.affiliation: Sector of Biological and Soft Systems, The Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom;
authors.forename: Pietro
authors.initials: P
authors.lastname: Cicuta
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.
authors.forename: Tom P
authors.initials: TP
authors.lastname: Monie
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom; ceb27@cam.ac.uk.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Bryant
mesh_terms: D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000382:microbiology*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D020170:Caspase 1 / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism*; D004789:Enzyme Activation; D057809:HEK293 Cells; D006801:Humans; D058847:Inflammasomes / Q000502:physiology*; D007249:Inflammation; D053583:Interleukin-1beta / Q000378:metabolism; D008264:Macrophages / Q000382:microbiology*; D051379:Mice; D008822:Mice, Transgenic; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D012486:Salmonella typhimurium
chemical_list: D051017:Apoptosis Regulatory Proteins; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D058847:Inflammasomes; D053583:Interleukin-1beta; C512299:Ipaf protein, mouse; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D053181:Caspase 8; D020170:Caspase 1
keywords: ASC; bacteria; caspase-1; caspase-8; innate immunity