Junctional Adhesion Molecule C Protein & Antibody (JAM-C, JAM3 Protein) also known as Junctional adhesion molecule 3, JAM3, is a single-pass type I membrane protein which belongs to the immunoglobulin superfamily. It is an adhesion molecule expressed by endothelial cells (ECs) that plays a role in tight junction formation, leukocyte adhesion, and transendothelial migration. JAM-C is an adhesion molecule that is expressed on cells within the vascular compartment and epithelial cells and, to date, has been largely studied in the context of inflammatory events. JAM-C is also expressed in peripheral nerves and that this expression is localized to Schwann cells at junctions between adjoining myelin end loops. JAM-C is a component of the autotypic junctional attachments of Schwann cells and plays an important role in maintaining the integrity and function of myelinated peripheral nerves. JAM-C was recently shown to be a counter receptor for the leukocyte beta2-integrin Mac-1 (CD11b/CD18), thereby mediating interactions between vascular cells, particularly in inflammatory cell recruitment. JAM-C is up-regulated by oxidized low-density lipoprotein (LDL) and may thereby contribute to increased inflammatory cell recruitment during atherosclerosis. JAM-C may therefore provide a novel molecular target for antagonizing interactions between vascular cells in atherosclerosis. JAM-C was shown to undergo a heterophilic interaction with the leukocyte beta2 integrin Mac-1, thereby mediating interactions between vascular cells in inflammatory cell recruitment. JAM-C undergoes a homophilic interaction via the Arg64-Ile65-Glu66 motif on the membrane-distal Ig domain of the molecule. The homophilic interaction of JAM-C can mediate tumor cell-endothelial cell interactions and may thereby be involved in the process of tumor cell metastasis.
