Structure, function, and regulation of cellular tight junctions

Abstract

The tight junction (TJ) is a dynamic structure that is controlled, in part, by the activity of the cytoskeleton. It has become abundantly clear that, in the presence of Ca2+, assembly of the TJ is the result of cellular interactions that trigger a complex cascade of biochemical events that ultimately lead to the formation of an organized network of TJ elements, the composition of which remains unknown. The TJ functions both as a barrier between two fluid compartments and, to a lesser extent, as a fence between apical and basolateral membrane domains. To meet the many physiological and pathological challenges to which epithelia and endothelia are subjected, the TJ must be capable of a rapid and coordinated response, which depends on complex regulatory mechanisms. The precise characterization of the mechanisms involved in the assembly and regulation of the TJ is an area of current active investigation. However, until the biochemical composition of this structure has been defined and its gene identified, the TJ will continue to be an elusive yet tantalizing challenge to the cell biologist.

Human astrocytes/astrocyte-conditioned medium and shear stress enhance the barrier properties of human brain microvascular endothelial cells

“…Tight junctions in general, fulfill the two functions. First, they contribute to the maintenance of cell polarity [77,79], and second they seal the gap between adjacent cells and prevent uncontrolled paracellular exchange of small and macromolecules [66,77]. However, the sealing properties of tight junctions vary between endothelial cells of different locations.…”

Severe feed restriction increases permeability of mammary gland cell tight junctions and reduces ethanol stability of milk

“…TJs are structures located in the cell's apical domain, surrounding both endothelial and epithelial cells (Stelwagen et al, 1998a), with the so-called fence and barrier functions. They play an important role in maintaining cell-cell contact (Pitelka, 1978;cited by Zettl et al, 1992), separating its basolateral (interstitial fluid) and apical (alveolar lumen) sides (Schneeberger and Lynch, 1992) and controlling the paracellular movement of ions and small molecules between two fluid compartments (Stelwagen et al, 1998a). TJs are impermeable when in perfect condition, not allowing the influx of components from blood into milk, and vice-versa (Stelwagen et al, 1998a).…”

Restricted Localization of Claudin-16 at the Tight Junction in the Thick Ascending Limb of Henle's Loop Together with Claudins 3, 4, and 10 in Bovine Nephrons

“…68 (5): [453][454][455][456][457][458][459][460][461][462][463] 2006 Tight junctions (TJs) are located at the apicalmost region of lateral membranes of epithelial cells, and play a central role in sealing the intercellular space in epithelial cellular sheets. TJs create the primary barrier to the diffusion of solutes and water through the paracellular pathway and maintain cell polarity as a boundary between the apical and basolateral plasma membrane domains [7,26,29,34]. On freeze-fracture electron microscopy, TJs are visualized as a continuous anastomosing network of intramembranous particle strands, i.e., TJ strands, and complementary grooves [28].…”