Cytoplasmic tight junctional proteins

Figure 3 A hydrophobic permeant must negotiate through a complex series of diffu-sional and thermodynamic barriers as it penetrates into a cell. The lipid and protein compositions and charge distribution of the inner and outer leaflets of the membrane lipid bilayer can play limiting roles, particularly at the tight junction. Depending upon the permeant s characteristics, it may remain within the plasma membrane or enter the cytoplasm, possibly in association with cytosolic proteins, and partition into cytoplasmic membranes.

Tight junctions form selective barriers that regulate paracellular transport across epithelia and endothelia. Tight junctions are composed of transmembrane proteins (occludin, claudins, and JAMs) linked to the actin cytoskeleton through cytoplasmic ZO proteins, whereas adherence junctions are composed of the nectin-afadin system and the E-cadhcrin catenin system [143]. These cell cell adhesion proteins create the barrier and regulate electrical resistance, size, and ionic charge selectivity [144], Several experimental procedures have... 

---