A pore-forming toxin initiates ABI1 complex switching to promote bacterial cell-to-cell spread

influx, leading to calpain-mediated cleavage of the spectrin cytoskeleton. Spectrin cleavage mobilizes ABI1, allowing ABI1 to bind EPS8 and activate EPS8's actin capping activity to facilitate local actin recycling necessary for efficient protrusion elongation and cell-to-cell spread. These findings reveal an unrecognized host-pathogen interaction, in which a bacterial pore-forming toxin induces spatially confined cytoskeletal remodeling to promote cell-to-cell spread.