These new observations reveal a previously unappreciated complexity to platelet granule formation and exocytosis and challenge our earlier notions of how these granules are organized within platelets and contribute to the multitude of physiological activities in which platelets function.

Key Points VAMP-7 functions in platelet granule exocytosis and spreading. VAMP-7 associates with VARP and Arp2/3, thereby linking granule exocytosis and actin reorganization.