Participates in cell-cell adhesion. It is a counterreceptor for ITGAM, mediating leukocyte-platelet interactions and is involved in the regulation of transepithelial migration of polymorphonuclear neutrophils (PMN). The soluble form is a mediator of angiogenesis.
Highest expression in placenta, brain and kidney. Significant expression is detected on platelets. Expressed in intestinal mucosa cells. Expressed in the vascular endothelium. Found in serum (at protein level). Also detected in the synovial fluid of patients with rheumatoid arthritis, psoriatic arthritis or ostearthritis (at protein level).
Defects in JAM3 are the cause of hemorrhagic destruction of the brain with subependymal calcification and cataracts (HDBSCC) [MIM:613730]. A syndrome characterized by congenital cataracts and severe brain abnormalities apparently resulting from hemorrhagic destruction of the brain tissue, including the cerebral white matter and basal ganglia. Patients manifest profound developmental delay, and other neurologic features included seizures, spasticity, and hyperreflexia. Brain imaging shows multifocal intraparenchymal hemorrhage with associated liquefaction and massive cystic degeneration, and calcification in the subependymal region and in brain tissue.
Belongs to the immunoglobulin superfamily. Contains 1 Ig-like C2-type (immunoglobulin-like) domain. Contains 1 Ig-like V-type (immunoglobulin-like) domain.
Proteolytically cleaved from endothelial cells surface into a soluble form by ADAM10 and ADAM17; the release of soluble JAM3 is increased by proinflammatory factors.
Cell membrane. Cell junction > desmosome. Secreted > extracellular space. In epithelial cells, it is expressed at desmosomes but not at tight junctions. Localizes at the cell surface of endothelial cells; treatment of endothelial cells with vascular endothelial growth factor stimulates recruitement of JAM3 to cell-cell contacts.