EphA2 phosphorylates the cytoplasmic tail of Claudin-4 and mediates paracellular permeability.

Eph receptors and ephrin ligands are widely expressed in epithelial cells and mediate cell-cell interaction. EphA2 is expressed in various cancer tissues and cell lines. Although the mechanism of action of EphA2 is unknown, its expression correlates with progression of the malignant phenotype of cancerous tissues. Here, we have shown that EphA2 modulates the localization and function of claudin-4, a constituent of tight junctions. EphA2 associates with claudin-4 via their extracellular domains. This association, in turn, leads to phosphorylation of the cytoplasmic carboxyl terminus of claudin-4 at Tyr-208. The tyrosine phosphorylation of claudin-4 attenuates association of claudin-4 with ZO-1, decreasing integration of claudin-4 into sites of cell-cell contact and enhancing paracellular permeability. These results indicate that EphA2 moderates the function of tight junctions via phosphorylation of claudin-4.