claudin5

Claudin 5 is a protein that plays a crucial role in the formation and maintenance of tight junctions in vertebrate epithelial and endothelial cells. Tight junctions are specialized cell-cell adhesion complexes that seal the space between cells, thereby controlling the passage of molecules across cell layers. Claudin 5 is a member of the claudin family, a large group of integral membrane proteins that are the primary determinants of tight junction permeability and selectivity.

This protein is specifically found in endothelial cells, particularly in the blood-brain barrier and the blood-testis barrier. In these barrier systems, claudin 5 contributes significantly to the paracellular sealing, preventing the uncontrolled diffusion of substances from the bloodstream into sensitive tissues like the brain and testes. Its presence and specific arrangement within the tight junction complex are essential for maintaining the integrity and selective permeability of these vital barriers.

Research has indicated that alterations in claudin 5 expression or function can have significant pathological consequences. For instance, dysregulation of claudin 5 has been implicated in various neurological disorders, inflammatory conditions, and even certain types of cancer, where it can affect tumor cell invasion and metastasis by compromising or altering barrier function. Understanding the precise role and regulation of claudin 5 is therefore an active area of biomedical research with potential therapeutic implications.