Actin cytoskeleton-organizing protein that plays a role in the formation of cell projections. Required for actin polymerization at immunological synapses (IS) and for the recruitment of the chemokine receptor CXCR4 to IS. Plays a role in dendritic spine morphogenesis and organization, including the localization of the dopamine receptor DRD1 to the dendritic spines. Involved in memory-related synaptic plasticity in the hippocampus.