L-selectin

L-selectin, also known as CD62L, is a cell adhesion molecule found on leukocytes. It belongs to the selectin family of proteins, which recognise sialylated carbohydrate groups. It is cleaved by ADAM17.

Ligands

 * GlyCAM-1, found in the high endothelial venules of the lymph nodes.
 * CD34, found on endothelial cells.
 * MadCAM-1, found on endothelial cells of gut associated lymphoid tissue.
 * PSGL-1, binds with low affinity.

Function
L-selectin acts as a "homing receptor" for leukocytes to enter secondary lymphoid tissues via the high endothelial venules. Ligands present on endothelial cells will bind to leukocytes expressing L-selectin, which causes the leukocytes to become localised at that point. The receptor is also found on the cell surfaces of "naive" T cells, which have not yet encountered their specific antigen. This surface expression is lost after the cells are activated.