Caspases are a family of cysteine proteases that can be divided into the apoptotic and inflammatory caspase subfamilies. Unlike the apoptotic caspases, members of the inflammatory subfamily are generally not involved in cell death but are associated with the immune response to microbial pathogens. Members of this subfamily include caspase-1, -4, -5, and -12. Activation of these caspases results in the cleavage and activation of proinflammatory cytokines such as IL-1β and IL-18. Caspase-5 can interact with caspase-1; both are constituents of the NALP1 inflammasome, a complex that can trigger the cleavage of pro-IL-1β. Expression of caspase-5 can be regulated by lipopolysaccharide (LPS) and IFN-gamma.