Recent advances in the structural biology of chondroitin sulfate and dermatan sulfate.

Recent glycobiology studies have suggested fundamental biological functions for chondroitin, chondroitin sulfate and dermatan sulfate, which are widely distributed as glycosaminoglycan sidechains of proteoglycans in the extracellular matrix and at cell surfaces. They have been implicated in the signaling functions of various heparin-binding growth factors and chemokines, and play critical roles in the development of the central nervous system. They also function as receptors for various pathogens. These functions are closely associated with the sulfation patterns of the glycosaminoglycan chains. Surprisingly, nonsulfated chondroitin is indispensable in the morphogenesis and cell division of Caenorhabditis elegans, as revealed by RNA interference experiments of the recently cloned chondroitin synthase gene and by the analysis of mutants of squashed vulva genes.