Schematic drawing of the biological functions of CS/DS on the cell surface or in the extracellular matrix. CS/DS chains play important roles on the cell surface or in the extracellular matrix. For instance, they regulate growth factor signaling, promote neurite outgrowth, are involved in cell adhesion by interacting with adhesion factors, and are recognized by microorganisms as infection receptors. In the figure, CS/DS chains are represented by alternating open and closed circles.