Syndecans are type I transmembrane proteins, with an N-terminal ectodomain that contains several consensus sequences for glycosaminoglycan (GAG) attachment and a short C-terminal cytoplasmic domain. Syndecans have attached heparan sulfate (HS) and to a lesser extent chondroitin sulfate (CS) chains. These allow interactions with a large number of proteins. Various enzymes involved in post-translational HS chain modifications produce unique binding motifs that selectively recognize different proteins (Tkachenko et al. 2005). HS chains facilitate interactions of syndecan-1 with extracellular matrix proteins, including several types of collagen (type I, III and V - Koda et al. 1985). It is thought that syndecans often act in concert with other receptors, e.g. alphavbeta3 and alphavbeta5 integrins 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). Similarly syndecan-1 appears to support integrin alpha2Beta1-mediated adhesion to collagen (human to cow collagen I - Vuoriluoto et al. 2008). 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).