Intestinal epithelial cell tight junction (TJ)

Intestinal epithelial cell tight junctions are multiprotein complexes at the apicolateral membrane of adjacent intestinal epithelial cells. Major proteins involved are claudins, occludin, junctional adhesion molecules (JAMs), tricellulin, and scaffolding proteins such as zonula occludens (ZO-1, ZO-2, ZO-3). Tight junctions seal the paracellular space, restrict diffusion of solutes and macromolecules, and demarcate apical/basolateral membrane domains. Their dynamic regulation maintains intestinal barrier integrity, and their dysfunction is implicated in multiple diseases, notably inflammatory bowel diseases, metabolic disorders, and autoimmune syndromes. They are not a single molecule or canonical receptor but a molecular complex formed by specific protein families. Drugs and dietary interventions may influence tight junction function indirectly, for example, by targeting protein phosphorylation pathways or expression levels

Other names

Intestinal tight junctionepithelial tight junctionzonula occludens (historically)TJ

Agents improve or disrupt barrier by modulating phosphorylation states of TJ proteins, inhibiting myosin light chain kinase (MLCK) activity, or changing expression of TJ constituent proteins (e.g., claudins, occludin, JAMs)