tiheliiduseid moodustavate valkude perekond, mis tekitavad epiteeli- ja endoteelirakkude vahel mitterakulise barjääri ja poorid, mille kaudu reguleeritakse molekulide liikumist läbi rakkudevahelise ruumi, Claudins are a family of proteins that are the most important components of the tight junctions, where they establish the paracellular barrier that controls the flow of molecules in the intercellular space between the cells of an epithelium. They have four transmembrane domains, with the N-terminus and the C-terminus in the cytoplasm.