The tight junction is an intracellular junctional structure that mediates adhesion between epithelial cells and is required for epithelial cell function. Tight junctions control paracellular permeability across epithelial cell sheets and also serve as a barrier to intramembrane diffusion of components between a cell's apical and basolateral membrane domains. Recent genetic and biochemical studi...

The human airway is lined with respiratory epithelial cells, which create a critical barrier through the formation of apical tight junctions. To investigate the molecular mechanisms underlying this process, an RNAi screen for guanine nucleotide exchange factors (GEFs) was performed in human bronchial epithelial cells (16HBE). We report that SOS1, acting through the Ras/MEK/ERK pathway, is essen...

Tight junctions are unique organelles in polarized epithelial and endothelial cells that regulate the flow of solutes and ions across the epithelial barrier. The structure and functions of tight junctions are regulated by a wide variety of signaling and molecular mechanisms. Several recent studies in mammals, drosophila, and zebrafish reported a new role for Na,K-ATPase, a well-studied ion tran...

The epithelial cell tight junction has several functions including the control of paracellular transport between epithelial cells. Renal paracellular transport has been long recognized to exhibit unique characteristics within different segments of the nephron, functions as an important component of normal renal physiology and has been speculated to contribute to renal related pathology if funct...

Cingulin, a component of vertebrate tight junctions, contains a head domain that controls its junctional recruitment and protein interactions. To determine whether lack of junctional cingulin affects tight-junction organization and function, we examined the phenotype of embryoid bodies derived from embryonic stem cells carrying one or two alleles of cingulin with a targeted deletion of the exon...

Tight junctions help prevent the passage of digestive enzymes and microorganisms through the space between adjacent epithelial cells lining. However, Helicobacter pylori encoded virulence factors negatively regulate these tight junctions and contribute to dysfunction of gastric mucosa. Here, we have predicted the regulation of important tight junction proteins, such as Zonula occludens-1, Claud...

Tight junctions are crucial for maintaining the polarity and vectorial transport functions of epithelial cells. We and others have shown that Na-K-ATPase plays a key role in the organization and permeability of tight junctions in mammalian cells and analogous septate junctions in Drosophila. However, the mechanism by which Na-K-ATPase modulates tight junctions is not known. In this study, using...