Claudin-15 (CLDN15)

Claudins function as major elements of the tight junction complexes that regulate the permeability of epithelia. Though some claudin family members serve as impermeable barriers, others mediate the permeability to ions and small molecules.

Often, several claudin family members are coexpressed and interact with each other, and this determines the overall permeability. CLDN15 forms tight junctions that mediate the paracellular transport of small monovalent cations along a concentration gradient, because of selective permeability for Na(+), Li(+) and K(+) ions, but chooses against Cl(-) ions.