Occludin is an approximately 60kDa-integral membrane protein localizing at Tight-Junction, and composed of short N-terminal cytosolic domain, four transmembrane domains and long C-terminal cytosolic domain. It is reported that Occludin has no homology to claudin family and forms strand by coporimerization with claudin family proteins. It is considered that Tight-Junction plays an important role in maintenance of cellular polarity (fence function) and in regulating the passage of ions and small molecular through the paracellular pathway (barrier function). For research use only, not for use in diagnostic procedures.