CK-666 is widely used in biological research as a selective inhibitor of the Arp2/3 complex, a key regulator of actin filament nucleation and branching. By inhibiting Arp2/3, CK-666 disrupts the formation of branched actin networks, making it a valuable tool for studying cell motility, lamellipodia formation, intracellular trafficking, and pathogen-induced actin remodeling. It is commonly applied in cell-based assays to probe the role of actin dynamics in processes such as cell migration, endocytosis, and cancer cell invasion. Due to its reversible and specific mode of action, CK-666 allows for precise temporal control in experimental settings, enabling researchers to dissect the contribution of the Arp2/3 complex in various cellular functions without permanently altering genetic or structural components.