Syndecans have attached heparan sulfate (HS) and to a lesser extent chondroitin sulfate (CS) chains. These allow interactions with a large number of proteins, including vitronectin (VTN) (Wilkins-Port & McKeown-Longo 1996, Wilkins-Port et al. 2003). It is thought that syndecans often act in concert with other receptors, e.g. integrins alphavbeta3 and alphavbeta5 cooperate with syndecan-1 during adhesion to vitronectin (Beauvais et al. 2004, McQuade et al. 2006) while alpha2beta1 and alpha6beta4 integrins cooperate with syndecans during adhesion to laminin (laminin alpha-1 Hozumi et al. 2006, laminin gamma-2, Ogawa et al. 2007). This relationship between syndecans and co-receptors is not well understood (Alexopoulou et al. 2007). Syndecan-null mice have subtle phenotypes when compared with mice deficient in HS chain synthesis or modification (Echtermeyer et al. 2001, Ishiquro et al. 2001, Götte et al. 2002). GPI-anchored glypicans and matrix HSPGs such as perlecan may compensate for the absence of syndecans.