Proposed consequence of mutated Aip1. Neutrophil migration and spreading requires dynamic polymerization/depolymerization of the cytoskeletal actin, altering the fluidity of the cytosol (gel↔sol transformations) and promoting changes in cellular morphology. Aip1 is thought to bind to cofilin and enhance its actin depolymerizing activity. Mutations affecting Aip1 either disrupt its interactions with cofilin (failure to enhance its activity), promoting the accumulation of F-actin and disrupting the cytoskeletal organization of the cytosol.