Adapter protein that binds F-actin and DNM1, and thereby plays a role in receptor-mediated endocytosis. Plays a role in the reorganization of the actin cytoskeleton, formation of cell projections, such as neurites, in neuron morphogenesis and synapse formation via its interaction with WASL and COBL. Does not bind G-actin and promote actin polymerization by itself. Required for the formation of organized podosome rosettes (By similarity). May act as a common effector of antigen receptor-signaling pathways in leukocytes. Acts as a key component of the immunological synapse that regulates T-cell activation by bridging TCRs and the actin cytoskeleton to gene activation and endocytic processes. Interacts with SHANK2, SHANK3 and SYN1. Interacts with FGD1 and DNM1. Interacts with ANKRD54. Interacts with COBL. Interacts with WASL and WIPF1 (By similarity). Interacts with MAP4K1 and PRAM1. Associates with lamellipodial actin and membrane ruffles. Colocalizes with actin and cortactin at podosome dots and podosome rosettes. The SH3 domain mediates interaction with SHANK2, SHANK3 and PRAM1. Degraded by caspases during apoptosis. Belongs to the ABP1 family.