Description
PECAM-1, or platelet endothelial cell adhesion molecule-1, also called CD31, is made up of six extracellular immunoglobulin-like domains, a single transmembrane domain, and a cytoplasmic domain containing serine and tyrosine residues that when phosphorylated, activate the molecules signaling function. It is expressed on platelets, monocytes, neutrophils, bone marrow macrophage and dendritic cells precursors, and at the intracellular junction of endothelial cells. PECAM-1, on the endothelial lining of blood vessels, helps maintain the vascular barrier. In response to inflammatory mediators, the endothelial pull away from each other allowing fluid, inflammatory cells and proteins into the extravascular space. The inflammatory response fades as adhesion of neighboring cells increase. PECAM-1 also plays an important role in angiogenesis, promoting endothelial cell motility, junctional development and capillary morphogenesis