CK-666 is primarily used in research settings as a selective inhibitor of the Arp2/3 complex, which plays a crucial role in actin polymerization. By blocking this complex, CK-666 helps scientists study the dynamics of actin cytoskeleton reorganization, a process essential for cell motility, division, and shape maintenance. Its application is particularly valuable in understanding cellular mechanisms underlying processes like cancer metastasis, immune cell migration, and neuronal development. Additionally, CK-666 is utilized in pharmacological studies to explore potential therapeutic targets for diseases where actin regulation is disrupted, such as certain cancers and neurodegenerative disorders. Its ability to precisely inhibit actin nucleation makes it a powerful tool for dissecting the role of the Arp2/3 complex in various biological contexts.