The epithelial tissue is held intact by the formation of tight junctions between cells. The basic functional units that form adhesive contacts across cells are the tight junction strands, which are composed of transmembrane proteins such as claudin, occludin and tricellulin.

What forms tight junctions?

Tight Junctions are predominately formed through interactions between members of the Claudin family of proteins and other transmembrane components such as occludin, tricellulin and junctional adhesion molecules (JAMs).

What are tight junctions for?

Tight junctions form the border between the apical and basolateral cell surface domains in polarized epithelia, and support the maintenance of cell polarity by restricting intermixing of apical and basolateral transmembrane components.