Actin-binding protein that contains 2 major actin binding sites . Organizes filamentous actin into parallel bundles . Plays a role in the organization of actin filament bundles and the formation of microspikes, membrane ruffles, and stress fibers . Important for the formation of a diverse set of cell protrusions, such as filopodia, and for cell motility and migration . Mediates reorganization of the actin cytoskeleton and axon growth cone collapse in response to NGF