Syndecans are type I integral membrane proteoglycans that are involved in cell-extracellular matrix adhesion and growth factor binding. Syndecan-1 is an matrix receptor which binds to Collagens, Fibronectin and Thrombospondin. Syndecan-1 and Syndecan-3 interact with MK (midkine), a growth/differentiation factor involved in embryogenesis. Syndecan-2 is highly expressed at areas of high morphogenetic activity, such as epithelial-mesenchymal interfaces and the prechondrogenic and preosteogenic mesenchymal condensations. Syndecan-4 functions cooperatively with integrins in the processes of cell spreading and focal adhesion assembly.