Adhesion molecules

Adhesion molecules are proteins involved in the binding of cells either to other cells or to components of the extracellular matrix. In addition, adhesion molecules can participate in cell signaling or display enzymatic activities. For example, the oxidase activity of vascular adhesion protein-1 (VAP-1) controls leukocyte infiltration into tissues and induces endothelial E- and P-selectins. Cell junctions play an important role in cell-to-cell adhesion and cell barrier functions. Together with gap junctions and adherens junctions, tight junctions form apical junctional complexes in epithelial and endothelial cells. These junctions hold cells together and prevent the passage of molecules and ions through the intercellular space. Furthermore, they block the movement of integral membrane proteins between the apical and basolateral surfaces of the cell.