This gene encodes a member of the claudin family. Claudins are integral membrane proteins and components of tight junction strands. Tight junction strands serve as a physical barrier to prevent solutes and water from passing freely through the paracellular space between epithelial or endothelial cell sheets, and also play critical roles in maintaining cell polarity and signal transductions. This gene is upregulated in patients with ulcerative colitis and highly overexpressed in infiltrating ductal adenocarcinomas. PKC/MAPK/AP-1 (protein kinase C/mitogen-activated protein kinase/activator protein-1) dependent pathway regulates the expression of this gene in gastric cells. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jun 2010],
Function:
Function:Plays a major role in tight junction-specific obliteration of the intercellular space, through calcium-independent cell-adhesion activity.,similarity:Belongs to the claudin family.,tissue specificity:Concentrated at the cell-cell borders of epithelial cells.,
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Cellular Localization:
Membranous
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Tissue Expression:
Isoform A1: Expression is restricted to the lung (PubMed:19047087). Isoform A2: Expression is restricted to the stomach mucosa where it is predominantly observed in the epithelial cells of the pit region and the base of the gastric glands including exocrine and endocrine cells (at protein level) (PubMed:19047087).