Inflammasome components, assembly, and activation. Microbial and nonmicrobial stimuli can induce the activation of the NLRP3 inflammasome. The NLRP3 inflammasome consists of a nucleotide-binding-oligomerization-domain- (NOD-) like receptor (NLR) that can be activated by certain bacterial toxins containing specific pathogen-associated molecular patterns (PAMPs), in the presence of extracellular adenosine triphosphate (ATP). Oligomerization of the NLR and ASC results in a macromolecular complex capable of cleaving procaspase-1 to its active form, which in turn cleaves the proforms of IL-1β and IL-18 to their biologically active forms.