Exploring the Allosteric Response of Fascin to Its Inhibitor

Fascin is a major actin-binding protein (ABP) for stabilizing filopodia to support efficient adhesion and migration of cancer cells. Fascin is also highly expressed in metastatic tumors. Disrupting the actin-binding site (ABS) on fascin constitutes a critical approach to hindering tumor metastasis. The G2 series of small molecules was formulated with the specific purpose of obstructing the binding pocket of fascin. The determination of inhibitor-induced structural dynamics in fascin is crucial for a comprehensive of its biological functions and the strategic development of pharmacological interventions. In this study, we utilized both equilibrium and dynamical-nonequilibrium molecular dynamics (D-NEMD) to elucidate the molecular mechanisms responsible for transmitting structural changes when removing the G2 inhibitor, in both the wild type (WT) and its variants. Our findings indicate that when G2 is removed, structural dynamics in fascin originate from the G2 binding pocket of fascin and propagate signals through the conformational transformation that spans all four β-trefoil domains. Although different mutant variants demonstrated comparable conformational networks, they showed varying response times. However, the signaling pathways in mutants remained consistent in comparison to the WT fascin. This study provides valuable insights into the structural features and communication pathways of fascin and provides avenues for the development of targeted inhibitors with promising prospects in cancer therapy.