Basement membranes are thin extracellular matrices which provide structural support to endothelial and epithelial cells and which regulate the passage of macromolecules into the underlying stroma. Evidence is accumulating that implicates the basement membrane in maintenance of the differentiated state. This appears to involve interactions between proteins in the basement membrane and receptors on the surface of the overlying cells. Before these interactions can be understood in detail, it is first necessary to understand more about the macromolecules which make up the basement membrane and how these molecules are organized and assembled extracellularly. Compositional and biosynthetic studies will therefore be performed on basement membrane synthesized in vitro by bovine corneal endothelial cells. The changes in rates of accumulation of three cell adhesion proteins, fibronectin, laminin, and thrombospondin, in response to growth factors and compositional modification of the basement membrane, will be studied.
