Targeting the MNK1-MYH9 axis blocks YAP1 recruitment to prevent thrombosis and platelet activation-induced NETosis.

Platelet activation and neutrophil extracellular trap (NET) formation are critical drivers of immunothrombosis, yet the molecular crosstalk governing these processes remains incompletely understood. In this study, we unveil a distinct regulatory mechanism whereby Yes-associated protein 1 (YAP1) binds to non-muscle myosin heavy chain 9 (MYH9) to drive platelet activation and thrombosis. Interestingly, we identified MAPK-interacting kinase 1 (MNK1) as a natural competitive "structural shield" in this process. MNK1 physically interacts with MYH9 in resting platelets, thereby blocking the YAP1-binding site and preventing YAP1-mediated signaling. Leveraging this mechanism, we developed a peptide inhibitor R13 and a small molecule MD2. Notably, we demonstrate that MD2 functions as a structural scaffold stabilizer independent of its canonical kinase activity, effectively abrogating the pathological recruitment of YAP1 to MYH9 triggered by a broad spectrum of agonists, thereby potently suppressing platelet activation. Crucially, this inhibition effectively abolishes NET formation driven by platelet activation. Collectively, this study establishes a competitive "MNK1-MYH9-YAP1" switching axis, where targeting the MNK1-MYH9 complex via protein-protein interaction stabilization represents a promising and hemostatically sparing therapeutic strategy to combat immunothrombosis.