P-selectin is a cell adhesion molecule (CAM) found in granules in endothelial cells (cells lining blood vessels) and activated platelets. Other names for P-selectin include CD62P, Granule Membrane Protein 140 (GMP-140), and Platelet Activation-Dependent Granule to External Membrane Protein (PADGEM). It was first shown to be found in endothelial cells in 1989.

Function

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P-selectin plays an essential role in the recruitment of leukocytes (white blood cells) to the site of injury. When endothelial cells are activated by molecules such as histamine or thrombin during inflammation, P-selectin moves from an internal cell location to the endothelial cell surface. Once at the cell surface, it binds to a receptor on leukocytes, called PSGL-1. This initiates the leukocyte adhesion cascade, an essential step in inflammation. Once it has performed its role at the cell surface it is rapidly reinternalised, by endocytosis, and recycled back to newly forming Weibel-Palade bodies or degraded in lysosomes.

Location

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Endothelial cells: stored in the membrane of Weibel-Palade bodies.

Platelets: stored in alpha-granules.

See also

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• Selectin