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. The NLRC4 inflammasome is activated as part of the innate immune response to a range of intracellular bacteria. It senses pathogenic proteins of the type III secretion system (T3SS) and type IV secretion system (T4SS) such as flagellin and PrgJ-like rod proteins via the Naip proteins (Naip1, Naip2 or Naip5): specific Naip proteins recognize and bind pathogenic proteins, driving assembly and activation of the NLRC4 inflammasome. The NLRC4 inflammasome senses Gram-negative bacteria such as L.pneumophila and P.aeruginosa, enteric pathogens S.typhimurium (Salmonella) and S.flexneri and fungal pathogen C.albicans. In intestine, the NLRC4 inflammasome is able to discriminate between commensal and pathogenic bacteria and specifically drives production of interleukin-1 beta (IL1B) in response to infection by Salmonella or P.aeruginosa. In case of L.pneumophila infection the inflammasome acts by activating caspase-7.
Specificity
Natural and recombinant Mouse NLR family CARD domain-containing protein 4
Homooligomer; homooligomerizes following activation of Naip proteins by pathogenic proteins such as S.typhimurium (Salmonella) flagellin or PrgJ. Component of the NLRC4 inflammasome, at least composed of NLRC4, caspase-1 (CASP1) and some NAIP protein (Naip, Naip2 or Naip5). Interacts with Naip5 and Naip6; following Naip5 and Naip6 engagement by Salmonella flagellin. Interacts with Naip2; following Naip2 engagement by Salmonella PrgJ. Interacts with EIF2AK2/PKR.