6mks | pdb_00006mks
Cryo-EM structure of NLRC4-CARD filament
Structural highlights
Disease[NLRC4_HUMAN] The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. Function[NLRC4_HUMAN] Key component of inflammasomes that indirectly senses specific proteins from pathogenic bacteria and fungi and responds by assembling an inflammasome complex that promotes caspase-1 activation, cytokine production and macrophage pyroptosis (PubMed:15107016). The NLRC4 inflammasome is activated as part of the innate immune response to a range of intracellular bacteria (By similarity).[UniProtKB:Q3UP24][1] Publication Abstract from PubMedInflammasomes are supramolecular signaling platforms integral to innate immune defense against invading pathogens. The Nod Like Receptor (NLR) family apoptosis inhibitory protein (NAIP)*NLR family caspase-recruiting domain (CARD) domain-containing 4 (NLRC4) inflammasome recognizes intracellular bacteria and induces the polymerization of the caspase-1 protease, which in turn executes maturation of interleukin-1beta (IL-1beta) and pyroptosis. Several high-resolution structures of the fully assembled NAIP*NLRC4 complex are available, but these structures do not resolve the architecture of the CARD filament in atomic detail. Here, we present the cryo-EM structure of the filament assembled by the CARD of human NLRC4 (NLRC4(CARD)) at 3.4 A resolution. The structure revealed that the helical architecture of the NLRC4(CARD) filament is essentially identical to that of the downstream filament assembled by the CARD of caspase-1 (casp1(CARD)), but deviates from the split washer-like assembly of the NAIP*NLRC4 oligomer. Our results suggest that architectural complementarity is a major driver for the recognition between up- and downstream CARD assemblies in inflammasomes. Furthermore, a Monte Carlo simulation of the NLRC4(CARD) filament assembly rationalizes why an (un)decameric NLRC4 oligomer is optimal for assembling the helical base of the NLRC4(CARD) filament. Together, our results explain how symmetric and asymmetric supramolecular assemblies enable high-fidelity signaling in inflammasomes. Cryo-EM structure of the NLRC4(CARD) filament provides insights into how symmetric and asymmetric supramolecular structures drive inflammasome assembly.,Matyszewski M, Zheng W, Lueck J, Antiochos B, Egelman EH, Sohn J J Biol Chem. 2018 Nov 1. pii: RA118.006050. doi: 10.1074/jbc.RA118.006050. PMID:30385506[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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