Tight junction protein ZO-1 (TJP1)

TJP1, TJP2, and TJP3 are closely related scaffolding proteins which link tight junction (TJ) transmembrane proteins such as claudins, junctional adhesion molecules, and occludin to the actin cytoskeleton (PubMed:7798316, PubMed:9792688). The tight junction functions to restrict movement of substances through the paracellular space as well as a border between the compositionally distinct apical and basolateral plasma membrane domains of epithelial and endothelial tissues.

Necessary for lumenogenesis, and especially efficient epithelial polarization and barrier formation (By similarity). Plays a role in the regulation of cell migration by targeting CDC42BPB into the leading edge of migrating cells (PubMed:21240187).