A role for dystroglycan in basement membrane assembly

Basement membranes are composed of ordered arrays of characteristic extrace llular matrix proteins, but little is known about the assembly of these str uctures in vivo. We have investigated the function of dystroglycan, a cell- surface laminin receptor expressed by cells contacting basement membranes i n developing and adult tissues. We find that dystroglycan is required for t he formation of a basement membrane in embryoid bodies. Our results further indicate that dystroglycan-laminin interactions are prerequisite for the d eposition of other basement membrane proteins. Dystroglycan may exert its i nfluence on basement membrane assembly by binding soluble laminin and organ izing it on the cell surface. These data establish a role for dystroglycan in the assembly of basement membranes and suggest fundamental mechanisms un derlying this process.