HSPG2 (perlecan) is a modular proteoglycan primarily located in the basement membranes of vascularized tissues. It is involved in several developmental processes, both during embryogenesis and in human disease such as cancer and diabetes (Iozzo et al. 1994). Domain V of the core protein binds alpha-dystroglycan (Talts et al. 1999), which in vivo forms a membrane-associated heterodimer with beta-dystroglycan (Peng et al. 1998).