The tight junction: Structure and function

摘要: Abstract The tight junction (TJ) is a specialized structure that generally circumscribes the most apical region of lateral plasma membranes polarized epithelia and endothelia. It apparently consists two sets strands, one for each adjacent cell, which seal intercellular spaces, thus restricting passage substances through paracellular pathway. also forms boundary between basolateral membrane domains. Although polarization components may proceed independently TJ, they segregate certain proteins lipids into their respective domains, preventing intermixing. molecular nature sealing element still unknown, but such as ZO-1 cingulin have recently been isolated detected in association with cytoplasmic side TJ. A variety data now suggest TJ are highly dynamic structures, sensitive to envronmental cellular factors. They able control pathway depending on physiological requirements, presumably regulatory mechanisms interactions cytoskeletal microfilament system. Their assembly depend extracellular Ca 2+ , cell-adhesion mechanisms, recognition cascades events yet be determined. Determination near future composition its mechanism will undoubtedly contribute basic understanding these important specializations health disease.