Tight junction and gap junction complexes (TJ/GJ complexes)

Tight junction and gap junction complexes are fundamental structural components of epithelial and endothelial cell membranes that maintain tissue integrity and facilitate communication. Tight junctions (TJs), primarily composed of claudins, occludin, and junctional adhesion molecules (JAMs), form a selective barrier that regulates the paracellular transport of ions and solutes while maintaining cell polarity (StatPearls, 2023). Gap junctions (GJs) consist of connexin proteins that assemble into hemichannels (connexons), allowing the direct exchange of ions, metabolites, and secondary messengers between adjacent cells (NIH, 2022). In disease states, the breakdown of TJs is a hallmark of inflammatory bowel disease and cancer metastasis, where loss of adhesion allows for cellular invasion (PubMed, 2021). Conversely, specific TJ proteins like Claudin 18.2 have emerged as high-value therapeutic targets in gastric and pancreatic cancers, addressed by monoclonal antibodies like zolbetuximab (Astellas, 2024). Gap junctions are targeted in conditions ranging from cardiac arrhythmias to chronic wound healing, where modulating intercellular communication can restore normal tissue function (Nature Reviews Drug Discovery, 2020). Therapeutic intervention often focuses on either restoring barrier function or selectively disrupting it for drug delivery, as well as blocking aberrant gap junctional communication in pathological states.

Other names

Intercellular junctional complexesZonula occludens and nexusEpithelial junctional complexCell-cell junctions

Monoclonal antibody-mediated cell lysis (ADCC) targeting specific claudin isoforms, and small molecule or peptide-based inhibition of connexin hemichannels and gap junctional intercellular communication.