Laminins bind to HSPG2 (perlecan) through interactions with its heparan sulfate sidechains (Battaglia et al. 1992, Behrens et al. 2012). The E3 fragment of laminin (containing the C-terminal LG4-LG5 domain pair) harbours binding sites for heparin, sulfatides and the cell surface receptor dystroglycan (Andac et al. 1999, Tisi et al. 2000) This interaction, rather than nidogen-mediated association, has been proposed to be the structural basis for association of the laminin and collagen type IV networks in basement membrane (Behrens et al. 2012). Alternatively the heparan sulfate chains of both perlecan and agrin might extend from a nidogen-containing laminin network to bind type IV collagen (Hohenester & Yurchenko 2013).