The IPAF (NLRC4) inflammasome can be activated by several stimuli, most notably by Gram-negative bacteria with either type III or type IV secretion systems that result in cytosolic flagellin, which is recognized by the IPAF inflammasome (Miao et al. 2006). IPAF also recognizes the rod-component of the type III secretion system which shares a sequence motif with flagellin that is essential for detection (Miao et al. 2010). Detection of Legionella and/or flagellin may also involve NAIP5 (Zamboni et al. 2006, Lightfield et al. 2008). IPAF contains a CARD domain and can interact directly with procaspase-1 (Poyet et al. 2001) but ASC increases the maximal activation of caspase-1 in response to S. typhimurium (Mariathasan et al. 2004), S. flexneri, and P. aeruginosa suggesting a possible collaboration with a PYD-containing NLRP for responses to these pathogens (Schroder & Tschopp, 2010). IPAF mediated caspase-1 activation can lead to a particular type of cell death called 'pyroptosis' (see Schroder & Tschopp 2010).