Wiley-Blackwell Functions of the Proteoglycans (Novartis Foundation Symposia)

Proteoglycans are macromolecules containing glycosaminoglycan chains covalently bound to protein cores. In this symposium workers from a range of disciplines (biochemistry, cell biology, pathology and developmental biology among others) focus on the structure and functions of the many types of proteoglycan found in mammalian tissues. The proteoglycans are a major ingredient of the extracellular matrix of connective tissue and help determine its properties. The structure of the large proteoglycan of cartilage has been elucidated in part and distinct families of small proteoglycans are now being identified in skin, bone, cartilage, sclera, tendon and arterial wall. Proteoglycans occur on cells as well as between them. The surface location of these largely heparan sulphate proteoglycans gives them a role in cell-cell and cell-matrix attachments. Several chapters of the symposium deal with these adhesive responses, which involve interactions with the cytoskeleton and with extracellular molecules such as fibronectin. Other proteoglycans are basement membrane constituents; members of this proteoglycan family have been characterized in adult and embryonic tissues. The storage granules of mast cells, and the granules of cytotoxic NK (natural killer) cells, also contain proteoglycans; their function and fate in mast cell exocytosis and in the killing of tumour and other cells is being actively investigated, as reported here. Proteoglycans are immensely varied but already, molecular biological studies of their protein cores suggest that a relatively small number of major gene families may exist within this heterogeneous, multifunctional and fascinating group of molecules. Proteoglycans are major components of the extracellular matrix of connective tissues and also occur in cell surfaces, as mediators of cell attachment. Other proteoglycans are found in basement membranes and in the granules of mast cells and cytotoxic natural killer cells. The symposium emphasizes the structural and functional diversity of these fascinating macromolecules.