Does not have hemolytic activity but shows a strong cytotoxicity towards alveolar macrophages and neutrophils. The Gly-rich region is probably involved in binding calcium, which is required for target cell-binding or cytolytic activity. The three transmembrane domains are believed to be involved in pore formation by the cytotoxin. Palmitoylated by ApxIIIC. The toxin only becomes active when modified (By similarity). Belongs to the RTX prokaryotic toxin (TC 1.C.11) family.