Identification of an adhesion-associated protein of the retinal pigment epithelium.

The normal function of the retinal pigment epithelium (RPE) is dependent on the maintenance of tight adhesions between cells. In order to identify cell surface molecules which may be important for maintaining the integrity of the RPE, we have undertaken a combined functional, biochemical, and immunohistochemical analysis of cell surface proteins of the RPE. These studies have led to the identification of a 100-kD cell surface protein whose presence correlates with the maintenance of calcium-dependent adhesions between RPE cells. In intact RPE tissue the protein is concentrated at the junctions between RPE cells. The properties of the protein suggest that it may be a member of the cadherin family of calcium-dependent cell adhesion proteins.