2. Academic Validation
  3. Molecular mechanism for NLRP6 inflammasome assembly and activation

Molecular mechanism for NLRP6 inflammasome assembly and activation

  • Proc Natl Acad Sci U S A. 2019 Feb 5;116(6):2052-2057. doi: 10.1073/pnas.1817221116.
Chen Shen 1 2,  Alvin Lu 1 2,  Wen Jun Xie 3,  Jianbin Ruan 1 2,  Roberto Negro 1 2,  Edward H Egelman 4,  Tian-Min Fu 5 2,  Hao Wu 5 2
Affiliations

Affiliations

  • 1 Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115.
  • 2 Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115.
  • 3 Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139.
  • 4 Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908.
  • 5 Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115; Tianmin.Fu@childrens.harvard.edu wu@crystal.harvard.edu.
PMID: 30674671 DOI: 10.1073/pnas.1817221116
Abstract

Inflammasomes are large protein complexes that trigger host defense in cells by activating inflammatory caspases for cytokine maturation and Pyroptosis. NLRP6 is a sensor protein in the nucleotide-binding domain (NBD) and leucine-rich repeat (LRR)-containing (NLR) inflammasome family that has been shown to play multiple roles in regulating inflammation and host defenses. Despite the significance of the NLRP6 inflammasome, little is known about the molecular mechanism behind its assembly and activation. Here we present cryo-EM and crystal structures of NLRP6 pyrin domain (PYD). We show that NLRP6 PYD alone is able to self-assemble into filamentous structures accompanied by large conformational changes and can recruit the ASC adaptor using PYD-PYD interactions. Using molecular dynamics simulations, we identify the surface that the NLRP6 PYD filament uses to recruit ASC PYD. We further find that full-length NLRP6 assembles in a concentration-dependent manner into wider filaments with a PYD core surrounded by the NBD and the LRR domain. These findings provide a structural understanding of inflammasome assembly by NLRP6 and other members of the NLR family.

Keywords

NLRP6; X-ray crystallography; cryo-EM; inflammasome; innate immunity.

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