Endothelial functions of platelet/endothelial cell adhesion molecule-1 (CD31)

Purpose of review The purpose of this article is to describe the function of the vascular cell adhesion and signaling molecule, platelet/endothelial cell adhesion molecule-1 (PECAM-1), in endothelial cells, with special emphasis on its role in maintaining and restoring the vascular permeability barrier following disruption of the endothelial cell junction. Recent findings In addition to its role as an inhibitory receptor in circulating platelets and leukocytes, PECAM-1 is highly expressed at endothelial cell–cell junctions, where it functions as an adhesive stress-response protein to both maintain endothelial cell junctional integrity and speed restoration of the vascular permeability barrier following inflammatory or thrombotic challenge. Summary Owing to the unique ability of antibodies that bind the membrane proximal region of the extracellular domain to trigger conformational changes leading to affinity modulation and homophilic adhesion strengthening, PECAM-1 might be an attractive target for treating vascular permeability disorders.