Structural Features of Tight-Junction Proteins

Abstract

Tight junctions are complex supramolecular entities composed of integral membrane proteins, membrane-associated and soluble cytoplasmic proteins engaging in an intricate and dynamic system of protein–protein interactions. Three-dimensional structures of several tight-junction proteins or their isolated domains have been determined by X-ray crystallography, nuclear magnetic resonance spectroscopy, and cryo-electron microscopy. These structures provide direct insight into molecular interactions that contribute to the formation, integrity, or function of tight junctions. In addition, the known experimental structures have allowed the modeling of ligand-binding events involving tight-junction proteins. Here, we review the published structures of tight-junction proteins. We show that these proteins are composed of a limited set of structural motifs and highlight common types of interactions between tight-junction proteins and their ligands involving these motifs.

ROCK inhibitor combined with Ca2+ controls the myosin II activation and optimizes human nasal epithelial cell sheets

“…Claudin-1 and ZO-2 were expressed in the upper layer of the cell sheet under all experimental conditions (Fig. S6), indicating the presence of tight junctions 42,43 . Although adherens junctions were observed in the basal layer by TEM when normal KCM (1.6 mM Ca 2+ ) was used (Fig.…”

Paranode stability requires UNC5B expression by oligodendrocytes

“…Occludens-1, 2 and 3 (ZO-1, 2, 3), link transmembrane junction proteins to the underlying cytoskeleton (Stevenson and Keon, 1998). ZU5 domains are found in the UNC5B intracellular domain and in ZO-1, in which it contributes to linking tight and adherens junctions to the cytoskeleton (Heinemann and Schuetz, 2019;Schultz et al, 1998).…”

Zonula occludens and nasal epithelial barrier integrity in allergic rhinitis

“…ZO-1 and ZO-2 have been detected in human nasal mucosa where ZO-1 is found in the uppermost layer of epithelium ( Kojima et al, 2013 ). ZO-1 protein contains an N-terminal PDZ domain that can recognize specific C-terminal or other peptide motifs to assemble with other TJ molecules such as claudins to form a TJ barrier at gaps between epithelial cells ( Heinemann & Schuetz, 2019 ; Herve et al, 2014 ; Umeda et al, 2006 ). The TJ barrier controls the diffusion of molecules by acting as semipermeable diffusion barriers through the paracellular pathway.…”