Regulation of adhesion-related protein tyrosine kinases during in vitro differentiation of retinal pigment epithelial cells: translocation of pp60c-src to the nucleus is accompanied by downregulation of pp125FAK.

In the present report we show that induction of expression of a differentiated phenotype in cultured retinal pigmented epithelium of chick embryo is accompanied by coordinate regulation of expression and distribution of two adhesion-related nonreceptor protein tyrosine kinases, pp60c-src and pp125FAK. pp60c-src translocates from the cell surface in flat undifferentiated cells to the nucleus in the packed differentiated cells. In contrast, pp125FAK, abundant in focal adhesions of flat undifferentiated cells, is downregulated in cells that have differentiated and packed into an epithelial sheet.