Actin-binding protein that contains 2 major actin binding sites (PubMed:8769857). Organizes filamentous actin into parallel bundles (PubMed:8769857). 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 (By similarity). Interacts with RUFY3 (via N-terminus); the interaction induces neuron axon development (By similarity). Interacts with NGFR (PubMed:22155786). Associates with CTNNB1 (By similarity). Interacts with PLXNB3 (By similarity). Colocalized with RUFY3 and F-actin at filipodia of the axonal growth cone. Colocalized with DBN1 and F-actin at the transitional domain of the axonal growth cone. Detected in embryonic brain and brain from young rats (at protein level). Composed of four fascin beta-trefoil domains. Phosphorylation at Ser-39 inhibits actin-binding. Phosphorylation is required for the reorganization of the actin cytoskeleton in response to NGF. Belongs to the fascin family.