Alpha-dystroglycan (DG) binds G domain-like sequences in other extracellular matrix molecules such as AGRN (agrin) (Gee et al. 1994, Campanelli et al. 1994, Sugiyama et al. 1994, Yamada et al. 1996, Gesemann et al. 1996) and HSPG2 (perlecan) (Peng et al. 1998, Talts et al. 1999). DG knockout mice exhibit severe disruption of basement membranes and embryonic stem cells fail to deposit laminin, suggesting a role for DG in laminin matrix formation (Henry & Campbell 1998). Conditional ablation of DG expression in cultured mammary epithelial cells disrupted laminin-111-induced polarity and beta-casein production, and abolished laminin binding and assembly on the cell surface. Dystroglycan re-expression restored these deficiencies (Weir et al. 2006).