Tight junction and adherens junction proteins (TJ/AJ proteins)

Tight junction and adherens junction proteins are the primary components of the apical junctional complex (AJC), which regulates the permeability and structural integrity of epithelial and endothelial barriers (StatPearls, 2023). Tight junctions (TJs), including claudins, occludin, and zonula occludens (ZO) proteins, form a "gate" that controls the paracellular transport of ions and solutes and a "fence" that maintains cell polarity (UniProt). Adherens junctions (AJs), characterized by cadherins and catenins, provide the mechanical adhesive force necessary to hold cells together and link the plasma membrane to the actin cytoskeleton (PubMed, PMID: 28249132). In diseases such as cancer, the loss of E-cadherin is a key step in the epithelial-mesenchymal transition (EMT), facilitating metastasis, while TJ dysfunction is central to inflammatory conditions like Crohn's disease and celiac disease (NIH, 2022). Therapeutic strategies include the use of monoclonal antibodies like zolbetuximab to target claudin-18.2 in gastric tumors and peptides like larazotide to stabilize TJs in autoimmune disorders. However, targeting these proteins carries risks of systemic barrier failure and unintended permeability changes in non-target tissues.

Other names

Apical junctional complexIntercellular junction proteinsCell-cell adhesion proteinsJunctional proteins

Modulation of paracellular permeability, stabilization of junctional complexes, and targeted cytotoxicity against cells overexpressing specific junctional components.