A family of cell adhesion molecules that bind carbohydrates via a lectin-like domain. They are integral membrane glycoproteins with an N-terminal, C-type lectin domain. The prefix in the nomenclature reflects the tissue in which the selectin was first identified, and is not necessarily indicative of a functional role. E-selectin (endothelial selectin, CD62E, endothelial leucocyte adhesion molecule-1, ELAM-1, 610 aa) is up-regulated on endothelial cells at sites of inflammation where it contributes to trapping of neutrophils. L-selectin (leucocyte–endothelial cell adhesion molecule, LECAM, CD62L, LAM-1, MEL-14 antigen, leu-8, 372 aa) is important for the initial adhesion of circulating leucocytes to endothelium, the process of margination, and for lymphocyte homing to high endothelial venules in peripheral lymph nodes, Peyer's patches, and areas of inflammation. It is present on the surface of most haematopoietic cells and on mature monocytes, eosinophils, and neutrophils. Once the cell has left the circulation L-selectin is removed from the cell surface by a membrane-associated metallopeptidase, a sheddase. It binds to carbohydrates on CD34, CD162, GlyCam, and MAdCAM. Polymorphism in L-selectin is associated with diabetic nephropathy in type 2 diabetes. L-selectin on the trophoblast binds to ligands on the uterine wall and is important in establishing implantation. P-selectin (platelet selectin CD62P, PADGEM, GMP-140, LECAM-3, 830 aa) is found on megakaryocytes and is rapidly up-regulated in platelets and endothelial cells when activated, although only transiently expressed. It mediates rolling of neutrophils, platelets, and some T-cell subsets along the luminal surface of blood vessels.
Subjects: Medicine and Health — Chemistry.