Tight junctions (TJs) and adherens junctions (AJs) are key determinants of the structure and permeability of epithelial barriers. Although exocytic delivery to the cell surface is crucial for junctional assembly, little is known about the mechanisms controlling TJ and AJ exocytosis. This study was aimed at investigating whether a key mediator of exocytosis, soluble N-ethylmaleimide sensitive factor (NSF) attachment protein alpha (αSNAP), regulates epithelial junctions. αSNAP was enriched at apical junctions in SK-CO15 and T84 colonic epithelial cells and in normal human intestinal mucosa. siRNA-mediated knockdown of αSNAP inhibited AJ/TJ assembly and establishment of the paracellular barrier in SK-CO15 cells, which was accompanied by a significant down-regulation of p120-catenin and E-cadherin expression. A selective depletion of p120 catenin effectively disrupted AJ and TJ structure and compromised the epithelial barrier. However, overexpression of p120 catenin did not rescue the defects of junctional structure and permeability caused by αSNAP knockdown thereby suggesting the involvement of additional mechanisms. Such mechanisms did not depend on NSF functions or induction of cell death, but were associated with disruption of the Golgi complex and down-regulation of a Golgi-associated guanidine nucleotide exchange factor, GBF1. These findings suggest novel roles for αSNAP in promoting the formation of epithelial AJs and TJs by controlling Golgi-dependent expression and trafficking of junctional proteins.
Pubmed ID: 22485163 RIS Download
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Commercial antibody vendor which supplies antibodies and other products to life science researchers.
View all literature mentionsA contract research organization providing drug development and animal testing services. Under the name Covance Research Products Inc., based in Denver, Pennsylvania, the company also deals in the import, breeding and sale of laboratory animals. It breeds dogs, rabbits, guinea pigs, non-human primates, and pigs, and runs the largest non-human primate laboratory in Germany. (Wikipedia)
View all literature mentionsA second-generation retrovirus producer lines for the generation of helper free ecotropic and amphotropic retroviruses. The lines are based on the 293T cell line (a human embryonic kidney line transformed with adenovirus E1a and carrying a temperature sensitive T antigen co-selected with neomycin). The unique feature of this cell line is that it is highly transfectable with either calcium phosphate mediated transfection or lipid-based transfection protocols-- up to 50% or higher of cells can be transiently transfected. The lines were created by placing into 293T cells constructs capable of producing gag-pol, and envelope protein for ecotropic and amphotropic viruses. The lines offered advantages over previous stable systems in that virus can be produced in just a few days. Academic and non-profit laboratories may obtain the Phoenix cells from either Allele Biotechnology or the National Gene Vector Bank. The vectors may be obtained from Addgene. They are no longer distributing these reagents from the lab.
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