Alpha granule
Cellular component of platelets
Alpha granules, (α-granules) also known as platelet alpha-granules are a cellular component of platelets. Platelets contain different types of granules that perform different functions, and include alpha granules, dense granules, and lysosomes. Of these, alpha granules are the most common, making up 50% to 80% of the secretory granules. Alpha granules contain several growth factors.
01Contents
Contents include insulin-like growth factor 1, platelet-derived growth factors, TGF beta, 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.
02Clinical significance
A deficiency of alpha granules is known as gray platelet syndrome.
Sources and credits
This article is adapted from the Wikipedia article “Alpha granule”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Platelet structure.png by Dr Graham Beards, CC BY-SA 3.0
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