Heparan sulfate matrix proteins

Proteoglycans bind to a variety of different proteins and polysaccharides. For example, the large extracellular matrix protein tenascin, which is important to adhesion, cell migration, and proliferation, binds to chondroitin sulfate proteoglycans such as neurocan.225 Syndecan, a transmembrane proteoglycan, carries both chondroitin and heparan sulfate chains, enabling it to interact with a variety of proteins that mediate cell-matrix adhesion.185... 

Heparan sulfate consists of the repeating disaccharide /3-D-glucopyranosyluronic acid-(1 4)-iV-sulfato-2-amino-2-deoxy-a-D-glucopyranosyl linked (1 4). This polysaccharide is linked to a core protein to give a proteoglycan that is found as a matrix component of arterial wall, lung, heart, liver, and skin [93]. 

Proteoglycans are major components of the extracellular matrix in animal cells. They are composed of core proteins and glycosaminoglycan polysaccharides. Heparin and heparan sulfate are the most complex glycosaminoglycans, a family of molecules that also includes chon-... 

These are either integral membrane proteoglycans or are linked to the membrane via a phosphatidylinositol moiety. They appear to serve as receptors for growth factors and other components of the extracellular matrix, for cell-matrix and cell-cell interactions, and as receptors for other cell-cell interaction molecules. Usually it is the heparan sulfate glycosaminoglycan that is the interactive agent, although chondroitin sulfate and the core proteins have also been shown to function in this manner under some conditions. In addition there are reports of free glycosaminoglycan chains found in cell surfaces [147]. Their source and functions are unclear. 

A heparin-binding protein, named penetrin, has been characterized in T. cruzi (83). It is a 60 kDa protein located on the surface of trypomastigotes and adheres to heparin, heparan sulfate, and collagen, three components of the extracellular matrix (ECM). Coating of plastic surfaces with these molecules supported the attachment of T. cruzi. Therefore, penetrin may mediate interaction of T. cruzi with ECM and facilitate migration through basement membranes. In addition, penetrin binds to T. cruzi host cells, in a saturable and specific manner, suggesting that penetrin may also promote T. cruzi attachment to and invasion of host cells. Indeed, excess purified penetrin... 

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