Platelet alpha granule

Contents of alpha-granules

Contents include insulin-like growth factor 1, platelet-derived growth factors, TGFβ, platelet factor 4 (which is a heparin-binding chemokine) and other clotting proteins (such as thrombospondin, fibronectin, factor V, and von Willebrand factor).

The alpha granules express the adhesion molecule P-selectin and CD63. These are transferred to the membrane after synthesis.

The other type of granules within platelets are called dense granules.

Clinical significance

A deficiency of alpha granules is known as gray platelet syndrome.