Figure 2. Inflammatory caspases mediate an innate immune response to microbial invasion.
Cellular recognition of foreign invaders leads to formation of inflammatory caspase-containing protein complexes, called the inflammasomes. The best characterized is the NALP1 inflammasome, which consists of a NLR family member, an adaptor protein called ASC, and caspase-1/5. Inflammasome assembly leads to activation of caspase-1 and maturation of IL-1β. A recent study has implicated caspase-1 in regulating non-conventional protein secretion, which may be intimately involved in the inflammatory response (Keller et al., 2008). However the exact mechanism for caspase-1 in mediating protein secretion remains to be determined.