scholarly journals Full-length NLRP3 forms oligomeric cages to mediate NLRP3 sensing and activation

2021 ◽  
Author(s):  
Liudmila Andreeva ◽  
Liron David ◽  
Shaun Rawson ◽  
Chen Shen ◽  
Teerithveen Pasricha ◽  
...  
Keyword(s):  
Membrane Integrity ◽  
Full Length ◽  
Early Event ◽  
Inflammasome Activation ◽  
Leucine Rich Repeat ◽  
Nucleotide Binding Domain ◽  
Double Ring ◽  
Pyrin Domain ◽  
Stimulus Responsive ◽  
Golgi Network

The nucleotide-binding domain and leucine-rich-repeat (LRR) containing protein 3 with a pyrin domain (NLRP3) is emerging to be a critical intracellular inflammasome sensor of membrane integrity and a highly important clinical target against chronic inflammation. Here we report that the endogenous, stimulus-responsive form of full-length NLRP3 is a 12-16 mer double ring cage held together by LRR-LRR interactions with the pyrin domains shielded within the assembly to avoid premature activation. Surprisingly, this NLRP3 form is predominantly membrane localized, which is consistent with previously noted localization of NLRP3 at various membrane organelles. Structure-guided mutagenesis reveals that trans-Golgi network dispersion into vesicles, an early event observed for all NLRP3 activating stimuli, requires the double ring cages of NLRP3. Double ring-defective NLRP3 mutants further abolish inflammasome punctum formation, caspase-1 processing and cell death. Thus, unlike other inflammasome sensors that are monomeric when inactive, our data uncover a unique NLRP3 oligomer on membrane that is poised to sense diverse signals to induce inflammasome activation.

scholarly journals The Roles of Endoplasmic Reticulum in NLRP3 Inflammasome Activation

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1219 ◽  
Author(s):  
Yang Zhou ◽  
Zhizi Tong ◽  
Songhong Jiang ◽  
Wenyan Zheng ◽  
Jianjun Zhao ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Nlrp3 Inflammasome ◽  
Critical Role ◽  
Immune Defense ◽  
Inflammasome Activation ◽  
Nucleotide Binding Domain ◽  
Cholesterol Trafficking ◽  
Pyrin Domain ◽  
Nlrp3 Inflammasome Activation ◽  
Molecular Patterns

The NLRP3 (nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3) inflammasome senses pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), and activates caspase-1, which provokes release of proinflammatory cytokines such as interleukin-1β (IL-1β) and IL-18 as well as pyroptosis to engage in innate immune defense. The endoplasmic reticulum (ER) is a large and dynamic endomembrane compartment, critical to cellular function of organelle networks. Recent studies have unveiled the pivotal roles of the ER in NLRP3 inflammasome activation. ER–mitochondria contact sites provide a location for NLRP3 activation, its association with ligands released from or residing in mitochondria, and rapid Ca2+ mobilization from ER stores to mitochondria. ER-stress signaling plays a critical role in NLRP3 inflammasome activation. Lipid perturbation and cholesterol trafficking to the ER activate the NLRP3 inflammasome. These findings emphasize the importance of the ER in initiation and regulation of the NLRP3 inflammasome.

A ring-like model for ASC self-association via the CARD domain

Inflammasome ◽  
2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Eva de Alba ◽  
Clara M. Santiveri ◽  
Javier Oroz
Keyword(s):  
Protein Interactions ◽  
Adaptor Protein ◽  
Innate Immune ◽  
Inflammasome Activation ◽  
Type I ◽  
Nucleotide Binding Domain ◽  
Double Ring ◽  
Ring Model ◽  
Complex Process ◽  
Self Association

AbstractInflammasomes are molecular platforms controlling the innate immune response to pathogens and cellular stress. ASC is an adaptor protein common to most NLR (nucleotide-binding domain and leucine-rich repeat containing receptor) inflammasome complexes as its N-terminal PYD and C-terminal CARD interact with the homologous domains in NLR and procaspase-1. Although inflammasome activation depends on ASC oligomerization, the molecular basis of ASC self-association and the protein interactions mediating the inflammatory signaling pathway remain unknown. Both CARD and PYD domains are involved in the oligomerization process of ASC. Based on our previous structural and dynamics data on ASC we propose a model for its oligomerization consisting of a 7-member ring. In this model, CARD monomers associate via type I homotypic interactions leaving the remaining binding site of each monomer free for further oligomerization and thus ring formation. A second more open PYD ring is accommodated on top of the CARDs. Our model is discussed in light of previous work evidencing the formation of helical filaments and large globular structures by ASC. The double-ring model can help in the understanding of inflammasome assembly, nevertheless, ASC oligomerization has to be envisaged as a complex process that might include molecular organizations with structurally different features.

The zebrafish as a model to study the inflammasome

Inflammasome ◽  
2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Diego Angosto ◽  
Victoriano Mulero
Keyword(s):  
Animal Models ◽  
Mouse Model ◽  
Mouse Models ◽  
Mutant Mouse ◽  
Genetic Manipulation ◽  
Inflammasome Activation ◽  
Leucine Rich Repeat ◽  
Nucleotide Binding Domain ◽  
Evolutionary Aspects

AbstractOur knowledge about the inflammasome and the nucleotide-binding domain and leucine-rich repeat containing receptor (NLR) family has increased enormously during recent years due to studies in transgenic and mutant mouse models. Although the mouse provides many advantages for deciphering the mechanisms involved in inflammasome activation and its role in immunity, other animal models, such as the zebrafish may be complementary, especially for the in vivo visualization of inflammasome activation. Indeed, the zebrafish has emerged as an excellent model to study a wide variety of diseases due to its unique advantages, including its transparency and easy genetic manipulation. Here we briefly discuss the evolutionary aspects of the inflammasome and consider the use of the zebrafish to study the inflammasome complementary to the widely used mouse model.

scholarly journals The Roles of Inflammasomes in Host Defense against Mycobacterium tuberculosis

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 120
Author(s):  
Jialu Ma ◽  
Shasha Zhao ◽  
Xiao Gao ◽  
Rui Wang ◽  
Juan Liu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Host Defense ◽  
Inflammatory Responses ◽  
Inflammasome Activation ◽  
Caspase Activation ◽  
Nucleotide Binding Domain ◽  
Caspase 1 ◽  
Pyrin Domain

Mycobacterium tuberculosis (MTB) infection is characterized by granulomatous lung lesions and systemic inflammatory responses during active disease. Inflammasome activation is involved in regulation of inflammation. Inflammasomes are multiprotein complexes serving a platform for activation of caspase-1, which cleaves the proinflammatory cytokines such as interleukin-1β (IL-1β) and IL-18 into their active forms. These cytokines play an essential role in MTB control. MTB infection triggers activation of the nucleotide-binding domain, leucine-rich-repeat containing family, pyrin domain-containing 3 (NLRP3) and absent in melanoma 2 (AIM2) inflammasomes in vitro, but only AIM2 and apoptosis-associated speck-like protein containing a caspase-activation recruitment domain (ASC), rather than NLRP3 or caspase-1, favor host survival and restriction of mycobacterial replication in vivo. Interferons (IFNs) inhibits MTB-induced inflammasome activation and IL-1 signaling. In this review, we focus on activation and regulation of the NLRP3 and AIM2 inflammasomes after exposure to MTB, as well as the effect of inflammasome activation on host defense against the infection.

scholarly journals Development of an in vitro assay for the detection of polymerization of the pyrin domain of ASC

BioTechniques ◽  
2021 ◽  
Author(s):  
Ian P Bresch ◽  
Dominik A Machtens ◽  
Thomas F Reubold ◽  
Susanne Eschenburg
Keyword(s):  
Protein Complexes ◽  
In Vitro Assay ◽  
Innate Immune ◽  
Leucine Rich Repeat ◽  
Nucleotide Binding Domain ◽  
Vitro Assay ◽  
Microscale Thermophoresis ◽  
Pyrin Domain ◽  
Polymerization Behavior

Multicomponent protein complexes called inflammasomes play a major role in the innate immune system by activating proinflammatory cytokines and promoting a highly inflammatory form of programmed cell death, called pyroptosis. A hallmark of the function of the nucleotide-binding domain, leucine-rich repeat and NLRP3-mediated inflammasome assembly is the polymerization of ASC into large filaments. The ASC filaments recruit and activate procaspase-1 by induced proximity. We developed an in vitro assay for monitoring the polymerization of the pyrin domain of ASC by microscale thermophoresis. We have validated the assay by analyzing the effects of buffer conditions, mutations of ASC and the use of seeds on the polymerization behavior of ASC.

Sign in / Sign up

Export Citation Format

Share Document