title: Cryo-EM structure of the activated NAIP2-NLRC4 inflammasome reveals nucleated polymerization.
abstract: The NLR family apoptosis inhibitory proteins (NAIPs) bind conserved bacterial ligands, such as the bacterial rod protein PrgJ, and recruit NLR family CARD-containing protein 4 (NLRC4) as the inflammasome adapter to activate innate immunity. We found that the PrgJ-NAIP2-NLRC4 inflammasome is assembled into multisubunit disk-like structures through a unidirectional adenosine triphosphatase polymerization, primed with a single PrgJ-activated NAIP2 per disk. Cryo-electron microscopy (cryo-EM) reconstruction at subnanometer resolution revealed a ~90° hinge rotation accompanying NLRC4 activation. Unlike in the related heptameric Apaf-1 apoptosome, in which each subunit needs to be conformationally activated by its ligand before assembly, a single PrgJ-activated NAIP2 initiates NLRC4 polymerization in a domino-like reaction to promote the disk assembly. These insights reveal the mechanism of signal amplification in NAIP-NLRC4 inflammasomes.
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Liman
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Center for Quantitative Biology, Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China. Department of Cancer Immunology and Virology, Intel Parallel Computing Center for Structural Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.
authors.forename: Shuobing
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Ruan
authors.affiliation: Center for Quantitative Biology, Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China. Department of Cancer Immunology and Virology, Intel Parallel Computing Center for Structural Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.
authors.forename: Jiayi
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Tong
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yin
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Liron
authors.initials: L
authors.lastname: David
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Alvin
authors.initials: A
authors.lastname: Lu
authors.affiliation: Department of Cancer Immunology and Virology, Intel Parallel Computing Center for Structural Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA. Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Wei Li
authors.initials: WL
authors.lastname: Wang
authors.affiliation: Center for Nanoscale Systems, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Marks
authors.affiliation: Center for Quantitative Biology, Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Ouyang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xinzheng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Center for Quantitative Biology, Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China. Department of Cancer Immunology and Virology, Intel Parallel Computing Center for Structural Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA. Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA. wu@crystal.harvard.edu youdong_mao@dfci.harvard.edu.
authors.forename: Youdong
authors.initials: Y
authors.lastname: Mao
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA. wu@crystal.harvard.edu youdong_mao@dfci.harvard.edu.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D053468:CARD Signaling Adaptor Proteins / Q000737:chemistry; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D020170:Caspase 1 / Q000737:chemistry; D020285:Cryoelectron Microscopy; D007113:Immunity, Innate; D058847:Inflammasomes / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D051616:Neuronal Apoptosis-Inhibitory Protein / Q000737:chemistry*; D058105:Polymerization; D060066:Protein Interaction Maps; D017434:Protein Structure, Tertiary
chemical_list: D051017:Apoptosis Regulatory Proteins; D001426:Bacterial Proteins; D053468:CARD Signaling Adaptor Proteins; D002135:Calcium-Binding Proteins; D058847:Inflammasomes; C512299:Ipaf protein, mouse; C496802:Naip2 protein, mouse; D051616:Neuronal Apoptosis-Inhibitory Protein; D020170:Caspase 1