Selectins: cell surface lectins which mediate the binding of leukocytes to endothelial cells.

The selectins are the most recently identified family of cell adhesion molecules. The three known members of this family (L-, E- and P-selectin) mediate the binding of leukocytes to endothelial cells and are involved in the homing of lymphocytes to lymph nodes, as well as the extravasation of neutrophilic granulocytes into inflamed tissues. The lectin character of these cell adhesion molecules (CAMs) makes the selectin protein family unique among all known CAM families. The review will summarize present knowledge about the structural organization, the ligands identified (carbohydrates and glycoproteins) and the different regulation mechanisms of the cell surface activity of the three selectins.