187-1, N-WASP Inhibitor TFA, a 14-amino acid cyclic peptide, serves as an allosteric inhibitor of the neural Wiskott-Aldrich syndrome protein (N-WASP). This compound effectively suppresses actin assembly triggered by phosphatidylinositol 4,5-bisphosphate (PIP2), exhibiting a potent inhibitory concentration (IC 50) of 2 μM. Furthermore, 187-1, N-WASP Inhibitor TFA inhibits the activation of the Arp2/3 complex by N-WASP, maintaining the protein in its autoinhibited state, ensuring the prevention of its activation.