Platelet alpha-granule

Alpha granules (or α-granules) are a cellular component of platelets. Platelets contain different types of granules that perform different functions including alpha granules, dense granules, and lysosomes. Of these alpha granules are the most common. The term 'alpha granules' is used to describe granules containing several growth factors. Alpha granules (or α-granules) are a cellular component of platelets. Platelets contain different types of granules that perform different functions including alpha granules, dense granules, and lysosomes. Of these alpha granules are the most common. The term 'alpha granules' is used to describe granules containing several growth factors. 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. A deficiency of alpha granules is known as gray platelet syndrome.