Actin cytoskeleton-organizing protein that plays a role in the formation of cell projections (By similarity). Required for actin polymerization at immunological synapses (IS) and for the recruitment of the chemokine receptor CXCR4 to IS (By similarity). Plays a role in dendritic spine morphogenesis and organization, including the localization of the dopamine receptor DRD1 to the dendritic spines (By similarity). Involved in memory-related synaptic plasticity in the hippocampus (By similarity). Interacts with RUFY (By similarity). Interacts with CXCR4; this interaction is enhanced by antigenic stimulation (By similarity). Interacts (via ADF-H domain) with ZMYND8 (via PHD-type Zinc finger, Bromo and PWWP domains); the interaction leads to sequestering of ZMYND8 in the cytoplasm (By similarity). In the absence of antigen, evenly distributed throughout subcortical regions of the T-cell membrane and cytoplasm. In the presence of antigen, distributes to the immunological synapse forming at the T-cell-APC contact area, where it localizes at the peripheral and distal supramolecular activation clusters (SMAC). Colocalized with RUFY3 and F-actin at the transitional domain of the axonal growth cone. Brain neurons. ISGylated. Drebrins are classified into two forms of the embryonic type (E1 and E2) and one form of the adult type (A). The time course of their appearance are different from each other. Their structures are closely related. Adult rat brain expresses only drebrin A while drebrin E1 or E2 is observed in immature animals.