Plays an important role in the reorganization of the actin cytoskeleton. Regulates neuron morphogenesis and increases branching of axons and dendrites. Regulates dendrite branching in Purkinje cells (By similarity). Binds to and sequesters actin monomers (G actin). Nucleates actin polymerization by assembling three actin monomers in cross-filament orientation and thereby promotes growth of actin filaments at the barbed end. Can also mediate actin depolymerization at barbed ends and severing of actin filaments. Promotes formation of cell ruffles. Identified in a complex composed of ACTA1, COBL, GSN AND TMSB4X. Interacts (via WH2 domains) with actin monomers. Interacts with both PACSIN1 and DBNL. Identified in a complex composed of COBL, PACSIN1 and WASL. Interacts with PACSIN1, PACSIN2 and PACSIN3 (By similarity). Recruited to the cell membrane via interaction with PACSIN1. Colocalizes with the actin cytoskeleton. Detected throughout the neuron cell body, as well as in axons and dendrites (By similarity). Extended N-terminus.