Claudin-1: Proteins and Enzymes

Claudins are transmembrane proteins with four membrane-spanning regions that serve as the major cell-adhesion molecules of tight junctions. Tight junctions restrict the flow of ions and aqueous molecules between cells, and their permeability is determined by the profile of claudin expression and arrangement of claudins with other proteins at the paracellular barrier. The combination and proportion of claudins vary among different cell types.