Nervous system proteoglycans as modulators of neurite outgrowth

The proteoglycans are multifunctional macromolecules composed of a core pol ypeptide and a variable number of glycosaminoglycan chains. The structural diversity and complexities of proteoglycan expression in the developing and adult Nervous System underlies the variety of biological functions that th ese molecules fulfill. Thus, in the Nervous System, proteoglycans regulate the structural organisation of the extracellular matrix, modulate growth fa ctor activities and cellular adhesive and motility events, such as cell mig ration and axon outgrowth. This review summarises the evidences indicating that proteoglycans have an important role as modulators of neurite outgrowt h and neuronal polarity. Special emphasis will be placed on those studies t hat have shown that proteoglycans of certain subtypes inhibit neurite exten sion either during the development and/or the regeneration of the vertebrat e Central Nervous System. (C) 2000 Elsevier Science Ltd. All rights reserve d.