α-Granules are essential to normal platelet activity. These unusual secretory granules derive
their cargo from both regulated secretory and endocytotic pathways in megakaryocytes.
Rare, inheritable defects of α-granule formation in mice and man have enabled identification
of proteins that mediate cargo trafficking and α-granule formation. In platelets, α-granules
fuse with the plasma membrane upon activation, releasing their cargo and increasing
platelet surface area. The mechanisms that control α-granule membrane fusion have begun …