FIGURE 23-36 The inflammasome. The inflammasome is a type of complex that senses the presence of cytoplasmic pathogen-derived nucleic acids and can also be activated by other danger signals, including particulate matter such as uric acid crystals or even asbestos. There are close to two dozen proteins that can participate in the formation of these complexes to yield inflammasomes of different composition, two of which are represented here schematically. Ultimately, the fully assembled inflammasome activates caspase-1, the enzyme that converts pro-IL-1β into the active, cleaved cytokine IL-1β. NALP3 = a member of the protein family characterized by the presence of NACHT, LRR, and PYD domains; ASC = apoptosis-associated Speck-like protein containing a CARD (caspase recruitment domain).