ZO-3 is a member of the membrane associated guanylate kinse (MAGUK) family and are considered tight junction-associated proteins. Tight junctions are complexes of proteins that create intercellular boundaries between the plasma membrane domains of epithelial and endothelial cells. ZO-3 is believed to have both structural and signaling roles, and is characteristically defined by three protein-protein interaction modules: the PDZ domain, the SH3 domain and the guanylate kinase (GuK) domain. ZO-1 forms complexes with either ZO-2 or ZO-3. In addition, these proteins can also associate with claudin, occludin and F-actin at tight junction stands, where they provide a linkage between the actin cytoskeleton and the tight junction. ZO-1 expression is significantly reduced in many breast cancer lines. ZO-2 and ZO-3 are ubiquitously expressed within epithelial tight junctions, and unlike ZO-1, which is also expressed at cell junctions of cardiac myocytes, ZO-2 is not expressed in nonepithelial tissue.
Tight junction protein 3; tight junction protein 3 (zona occludens 3); Tight junction protein ZO-3; TJP-3; Zona occludens protein 3; Zonula occludens protein 3