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. The protein encoded by this gene is a developmentally expressed renal tight junction protein. This gene is expressed in the cecum, colon, liver and kidney of mice, but is not identified in rat tissues. Humans and chimpanzees lack this gene.