Amanda M. Marchiando

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In vitro studies have demonstrated that occludin and tricellulin are important for tight junction barrier function, but in vivo data suggest that loss of these proteins can be overcome. The presence of a heretofore unknown, yet related, protein could explain these observations. Here, we report marvelD3, a novel tight junction protein that, like occludin and(More)
Epithelial paracellular barrier function, determined primarily by tight junction permeability, is frequently disrupted in disease. In the intestine, barrier loss can be mediated by tumor necrosis factor (alpha) (TNF) signaling and epithelial myosin light chain kinase (MLCK) activation. However, TNF induces only limited alteration of tight junction(More)
BACKGROUND & AIMS Tumor necrosis factor (TNF) increases intestinal epithelial cell shedding and apoptosis, potentially challenging the barrier between the gastrointestinal lumen and internal tissues. We investigated the mechanism of tight junction remodeling and barrier maintenance as well as the roles of cytoskeletal regulatory molecules during TNF-induced(More)
Although the C-terminal cytoplasmic tail of the tight junction protein occludin is heavily phosphorylated, the functional impact of most individual sites is undefined. Here, we show that inhibition of CK2-mediated occludin S408 phosphorylation elevates transepithelial resistance by reducing paracellular cation flux. This regulation requires occludin,(More)
Autophagy is a process whereby a double-membrane structure (autophagosome) engulfs unnecessary cytosolic proteins, organelles, and invading pathogens and delivers them to the lysosome for degradation. We examined the fate of cytosolic Salmonella targeted by autophagy and found that autophagy-targeted Salmonella present in the cytosol of HeLa cells(More)
Epithelia form barriers that are essential to life. This is particularly true in the intestine, where the epithelial barrier supports nutrient and water transport while preventing microbial contamination of the interstitial tissues. Along with plasma membranes, the intercellular tight junction is the primary cellular determinant of epithelial barrier(More)
The perijunctional actomyosin ring contributes to myosin light chain kinase (MLCK)-dependent tight junction regulation. However, the specific protein interactions involved in this process are unknown. To test the hypothesis that molecular remodeling contributes to barrier regulation, tight junction protein dynamic behavior was assessed by fluorescence(More)
Polymorphisms in the essential autophagy gene Atg16L1 have been linked with susceptibility to Crohn's disease, a major type of inflammatory bowel disease (IBD). Although the inability to control intestinal bacteria is thought to underlie IBD, the role of Atg16L1 during extracellular intestinal bacterial infections has not been sufficiently examined and(More)
γδ intraepithelial lymphocytes (IELs) are located beneath or between adjacent intestinal epithelial cells and are thought to contribute to homeostasis and disease pathogenesis. Using in vivo microscopy to image jejunal mucosa of GFP γδ T-cell transgenic mice, we discovered that γδ IELs migrate actively within the intraepithelial compartment and into the(More)
We questioned how tight junctions contribute to intestinal barrier function during the cell shedding that is part of physiological cell renewal. Intravital confocal microscopy studied the jejunal villus epithelium of mice expressing a fluorescent zonula occludens 1 (ZO-1) fusion protein. Vital staining also visualized the cell nucleus (Hoechst staining) or(More)