Claudin-14 is a protein that in humans is encoded by the CLDN14 gene. It belongs to a related family of proteins called claudins. The protein encoded by CLDN14 is an integral membrane protein and a component of tight junctions, one mode of cell-to-cell adhesion in epithelial or endothelial cell sheets. Tight junctions form continuous seals around cells and serve as a physical barrier to prevent solutes and water from passing freely through the paracellular space.