CASP1 and infection: Both Naip5 and IPAF have been reported to physically interact, but the role of Naip5 in caspase-1 activation remains to be fully elucidated, as A/J mice (mice with a mutation that results in a non-functional Naip5) are able to secrete IL-1β following infection with S. typhimurium, P. aeruginosa, and L. monocytogenes (66, 71, 73) (Table 1).