ABSTRACT
Junctional adhesion molecules (JAMs) comprise a small family of immunoglobulinlike adhesion molecules. JAMs were originally identifi ed in leukocytes, endothelial and epithelial cells, and their main function has been considered to be regulation of cell-cell interactions during infl ammation. Meanwhile, the diversity of cell types that express JAMs has increased, and JAMs have been found on cells of the reproductive system, on cells of the nervous system, on fi broblasts and on stem cells. In addition, a number of extracellular ligands as well as intracellular binding partners were identifi ed. Two major functions can be attributed to JAMs: (1) the regulation of vascular infl ammation by mediating transient interactions of immune cells with endothelial cells and (2) the regulation of cellular polarization by mediating the targeting of cytoplasmic proteins to specifi c sites of cell-cell adhesion. Th rough the latter activity, JAMs are involved in processes such as the
formation of tight junctions in epithelial and endothelial cells, the development of spermatids or the formation of functional nerves. Recent evidence indicates that JAMs play a role in cell migration and proliferation, suggesting that their functions are more diverse than anticipated. Here, we will review the role of JAMs in diff erent biological systems.
