The innate immune system is critical for host defense against bacterial pathogens, as it detectspathogen-associated molecular patterns (PAMPs). Distinct forms of regulated cell death mediate antimicrobial host defense through a breadth of possible initiator molecules, driving the engagement and assembly of distinct signaling complexes. Pathogen infection of host cells triggers an inflammatory cell death termed pyroptosis via activation of inflammatory caspases. However, blockade of immune signaling kinases by the Yersinia virulence factor YopJ triggers cell death involving both apoptotic caspase-8 (Casp8) and pyroptotic caspase-1 (Casp1). While Casp1 is normally activated within inflammasomes, Yersinia-induced Casp1 activation is independent of known inflammasome components. We found that Casp8 is an essential initiator, and Casp1 an essential amplifier of its own activation. Furthermore, Casp8 is activated within multiple foci throughout the cell, followed by assembly of a canonical inflammasome speck, indicating that caspase-8 and canonical inflammasome complex assemblies are kinetically and spatially distinct. Caspase-11 (Casp11) is a pattern-recognition receptor that senses cytosolic LPS. In response, Casp11 assembles into a supramolecular organizing center (SMOC) designated the noncanonical inflammasome, where it is thought to undergo proximity-induced auto processing and become activated to mediate pyroptosis. We found that catalytic activity was required for LPS-induced Casp11 assembly in macrophages, and that both catalytic activity and auto processing were required for Casp11 oligomerization in an ectopic expression system, suggesting that catalytic activity and auto processing occur upstream of, and mediate, Casp11 oligomerization. Overall, our findings further define mechanisms of how the immune system responds to microbial infections via assembly of distinct cell death-mediating complexes.