The RPE plays a critical role in maintaining the viability of retinal neurons. This grant tests the hypothesis that FGFs and their receptors are segregated on the apical and basal surfaces of the RPE cells, and that loss of this polarization results in their proliferation. There are three specific aims, each with individual objectives. First, is the release of individual FGFs polarized in monolayers of human RPE in vitro. Second, are the distribution of high and low affinity FGF receptors polarized in human RPE monolayers. Third, do cell adhesion molecules regulate basic FGF gene expression.