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-4 was initially identified as a homologous protein to Caspase-1 and the C. elegans Ced-3 which could induce apoptosis in transfected cells. More recent studies have shown that it can be activated by ER stress and has been suggested to be involved in multiple neuronal pathologies such as Alzheimer’s disease.
