Proposed roles of PACSIN2 in megakaryocyte and platelet biology. (1) DMS formation is initiated by the activation of PACSIN2 tubulating activity by FlnA, leading to focal plasma membrane invagination. (2) PACSIN2 promotes vesicle budding from Golgi, thus facilitating the expansion of the DMS network. PACSIN normally localizes to the cleavage furrow of mitotic cells, where it couples the actomyosin contractile ring to the plasma membrane. (3-4) During megakaryocyte endomitosis, PACSIN2 could recruit FlnA that may decrease actomyosin activity, leading to abortive cytokinesis and multinucleation. (5) In platelets, PACSIN could support plasma membrane stability by activating WASP in the vicinity of the plasma membrane, thus promoting the polymerization of cortical actin.