Recombinant Human Syndecan-4 (rHuSDC-4)

Syndecan-4 also known as amphiglycan or ryudocan, is a member of the syndecan family of Type 1 transmembrane proteins capable of carrying heparan sulfate (HS) and chondroitin sulfate glycosaminoglycans. The four vertebrate syndecans have two conserved cytoplasmic domains and divergent extracellular portions, except for HS attachment sites. Syndecan4 is the most similar to Syndecan2, but is more universally expressed and is found in virtually every cell type. Expression can be upregulated by TGFβ2 and in response to mechanical stress in smooth muscle, wound healing, arterial injury or acute myocardial infarction, probably in response to at least one inflammatory mediator. Human Syndecan4 ECD shares approximately 79%, 78% and 81% aa identity with mouse, rat and porcine Syndecan4 ECD, respectively. Addition of 20 80 disaccharides per side chain adds considerably to the size of the 20 kDa core protein. Noncovalent homodimerization of Syndecan4 is dependent on the transmembrane domain. The HS chains can bind fibronectin, SDF1, antithrombin, FGF2, midkine and tissue factor pathway inhibitor and can present FGF2 to its receptors. Proteolytic cleavage by plasmin, thrombin or a metalloproteinase may create a functional ectodomain. Genetic disruption of the Syndecan4 gene causes a mild phenotype, presumably due to compensation by other syndecans, but mice have an increase in placental thrombi as well as defects in wound healing and response to endotoxin shock.