Fig. 1. Summary of biological functions of HS. HS proteoglycan (HSPG) consists of a core protein and HS polysaccharide side chains. HS chains interact with antithrombin to regulate blood coagulation process and to fibroblast growth factor (FGF) and FGF receptor to impact cell proliferation. HS also bind to chemokines to recruit leukocytes in response to inflammation. Herpes simplex virus (and other viruses) use HS on the cell surface to establish the infections. HSPG is one of the major components of endothelial glycocalyx, implementing in many other functions as discussed in the text.