Highly simplified diagram of signaling pathways involving β-catenin that may be relevant for RPE cell morphogenesis and susceptibility to age-related oxidative stress. N-cadherin is specified as the cadherin adhesion protein since it is the major cadherin of cultured human RPE cells; its role in cytoskeletal remodeling and morphogenesis is unclear. For more detailed pathway maps, see the Science database of cell signaling, The Signal Transduction Knowledge Environment (STKE), at http://stke.sciencemag.org/cm/. Abbreviations: APC (adenomatous polyposis coli), FOXO (forkhead box O), GSK (glycogen synthase kinase), Lrp (lipoprotein receptor-related proteins), Mitf (microphthalmia-associated transcription factor); TCF/LEF (T cell factor/lymphoid-enhancing factor), Tyrp (tyrosinase-related proteins).