SNAP-23 is the ubiquitously expressed homologue of the neuronal SNAP-25, which functions in synaptic vesicle fusion. We have investigated the subcellular localization of SNAP-23 in polarized epithelial cells. In hepatocyte-derived HepG2 cells and in Madin-Darby canine kidney (MDCK) cells, the majority of SNAP-23 was present at both the basolateral and apical plasma membrane domains with little ...

We have studied the effects of brefeldin A (BFA) on endocytosis and intracellular traffic in polarized MDCK cells by using the galactose-binding protein toxin ricin as a membrane marker and HRP as a marker of fluid phase transport. We found that BFA treatment rapidly increased apical endocytosis of both ricin and HRP, whereas basolateral endocytosis was unaffected, as was endocytosis of HRP in ...

BACKGROUND Influenza is a significant cause of morbidity and mortality. The recent pandemic of a novel H1N1 influenza virus has stressed the importance of the search for effective treatments for this disease. Essential oils from aromatic plants have been used for a wide variety of applications, such as personal hygiene, therapeutic massage and even medical practice. In this paper, we investigat...

P73, a member of p53 tumor suppressor family, plays a crucial role in tumor suppression and neural development. Due to the usage of two promoters, p73 is expressed as two isoforms, TAp73 and ∆Np73, with opposing functions. Here, we investigated the potential role of p73 in epithelial polarity and morphogenesis by using Madin-Darby canine kidney (MDCK) cells as a model system. We found that kn...

BACKGROUND Mesenchymal stromal cells (MSC) are fibroblast-like multipotent cells capable of tissue-repair properties. Given the essentiality of tight junctions (TJ) in epithelial integrity, we hypothesized that MSC modulate TJ formation, via the AMP-activated kinase (AMPK) pathway. Liver kinase-β1 (LKB1) and Ca2+-calmodulin-dependent protein kinase kinase (CaMKK) represent the main kinases that...

Transcellular transport of a variety of ligands may be an important mechanism by which regulatory substances reach their site of action. We have studied the transcellular transport of two 6,000-mol-wt proteins, epidermal growth factor (EGF) and insulin, across polarized Madin-Darby canine kidney (MDCK) cells grown on dual-sided chambers on a nitrocellulose filter substrate. When grown on these ...

Previous studies have demonstrated that bradykinin stimulates the rapid release of inositol 1,4,5 trisphosphate (IP3) from membrane phosphatidylinositol 4,5 bisphosphate (PIP2) in Madin-Darby canine kidney (MDCK) cells. Since current evidence would suggest that the activation of phospholipase C (PLC) is mediated through a guanine nucleotide-binding protein in receptor-mediated activation of PLC...

Clostridium perfringens epsilon toxin (ETX) rapidly kills MDCK II cells at 37°C, but not 4°C. The current study shows that, in MDCK II cells, ETX binds and forms an oligomeric complex equally well at 37°C and 4°C but only forms a pore at 37°C. However, the complex formed in MDCK cells treated with ETX at 4°C has the potential to form an active pore, since shifting those cells to 37°C results in...

The epithelial-specific adaptor AP1B sorts basolateral proteins, but the trafficking routes where it performs its sorting role remain controversial. Here, we used an RNAi approach to knock down the medium subunit of AP1B (mu1B) in the prototype epithelial cell line Madin-Darby canine kidney (MDCK). Mu1B-knocked down MDCK cells displayed loss of polarity of several endogenous and exogenous basol...

MDCK cells in culture form a functional transporting epithelium. Apical surface of MDCK monolayers are not adhesive to free MDCK cells that fail to grow attached to existing monolayers. In contrast, when plated at high density (106 cm-2) MDCK cells form multilayered structures in which only the outermost layer shows a typical apical surface (microvilli, tight junctions, etc). In the lower layer...