Tight-Junction Molecules / Tight Junction Proteins

Key features:

= a ring of proteins that seals apical epithelium; includes the integral membrane proteins occludin and claudin, in association with cytoplasmic Zonula Occludens (ZO) Proteins (Zoludins)

Occludin plays a role in regulating interactions between occludin and Zonula Occludens Protein-1 (ZO-1), which helps maintain a complete tight junction (TJ) complex and supports paracellular barrier function. Studies indicate that short-chain fatty acids (SCFA) enhance the intestinal barrier by boosting the expression of claudin. Junctional adhesion molecules (JAMs) are capable of recruiting scaffolding proteins and polarity complex proteins, which assist in establishing the basolateral and apical polarity of cell-cell junctions.
Li et al. 2020s

Gap junctions are complex structures that form intercellular channels that allow ions and small molecules to diffuse directly between adjacent epithelial cells through multiple pathways such as a pore pathway and a leaky pathway
Portincasa et al. 2022a Int. J. Mol. Sci. 23: 1105

The intestinal epithelial apical junctional complex, which includes tight and adherens junctions, contributes to the intestinal barrier function via their role in regulating paracellular permeability
Jin & Blikslager 2020

Tight-Junction Molecules / Tight Junction Proteins formed between enterocytes are numerous and selectively allow permeation of molecules while simultaneously walling the Lamina propria from the lumen. Many proteins are involved in Tight-Junction Molecules / Tight Junction Proteins maintenance, including occludin, claudins, cadherins, etc., and these proteins are integral in gut barrier maintenance
Rohr et al. 2020

A complex of transmembrane proteins interact or make contact across the intercellular spaces to form Tight Junction
Mitic et al. 2000 Am J Physiol Gastrointest Liver Physiol 279(2): G250-4
Van Itallie & Anderson 2006 Annu Rev Physiol 68: 403–29
Elkouby-Naor & Ben-Yosef 2010 Int Rev Cell Mol Biol 279: 1-32
Buckley & Turner 2018 Cold Spring Harb Perspect Biol 10(1): 1-16
Ma et al. 2018a In: Physiology of the Gastrointestinal Tract: Sixth Edition. London, United Kingdom, San Diego, CA, United States, Cambridge, MA, United States, Kidlington, United Kingdom: Elsevier Inc 587-639. 1-2.

These proteins include occludin, members of the claudin family of proteins, and the Junctional Adhesion Molecules (JAMs) family of proteins as well as cytosolic scaffold proteins, such as ZO-1, ZO-2, and ZO-3, which in turn anchor the transmembrane proteins to the actin cytoskeleton
Stevenson et al. 1986 J Cell Biol 103(3): 755-66
Mitic et al. 2000 Am J Physiol Gastrointest Liver Physiol 279(2): G250-4
Van Itallie & Anderson 2006 Annu Rev Physiol 68: 403–29
Van Itallie & Anderson 2014 Semin Cell Dev Biol 36: 157-65
König et al. 2016 Clin Transl Gastroenterol 7(10): e196
Ma et al. 2018a In: Physiology of the Gastrointestinal Tract: Sixth Edition. London, United Kingdom, San Diego, CA, United States, Cambridge, MA, United States, Kidlington, United Kingdom: Elsevier Inc 587-639. 1-2.

After treatment with an FXR agonist, recruitment of both NK cells and the NK cell-derived pro-inflammatory cytokine IFN-gamma was markedly reduced, leading to restoration of intestinal epithelial integrity through up-regulation of the tight junction proteins Claudin-1 / CLDN1, occludin, and ZO-1 and thus preventing translocation of bacteria across the gut wall
Verbeke et al. 2015 Am. J. Pathol. 185: 409–419

More than 40 TJ proteins have been identified, including occludin, claudin family proteins, and junction adhesion molecules
Das et al. 2012 Virchows Arch. 460: 261-270

The main integral proteins of the Tight junction proteins include occludin and claudins
Furuse et al. 1993 J Cell Biol 123: 1777-88
Furuse et al. 1998 J Cell Biol 141: 1539-50

PGE2 and PGI2 have a synergistic role in restoration of intestinal barrier function by increasing intracellular cAMP and Ca2+, respectively, which in turn signal cytoskeletal-mediated tight junction closure
Blikslager et al. 1997 J. Clin. Invest. 100: 1928–1933

Tight junctions are dynamic structures that are regulated by mediators such as Interferon Type II (IFN Type II) / Interferon Gamma (IFN-g), cAMP, and Ca2+
Duffey et al. 1981 Nature (Lond.). 294: 451-453
Palant et al. 1983 Am. J. Physiol. 245:C203-C212
Madara & Stafford 1989 J. Clin. Invest. 83: 724-727

Considering tight junctions control the passage of solutes via the paracellular space, the major route of transepithelial solute passage, physiologic control over tight junctions is of major physiologic importance
Madara 1989 J. Clin. Invest. 83:1089–1094

see also:
Epithelial Barrier Integrity / Mucosal Barrier Integrity
Occludin