Role of heparan sulfate proteoglycans in cell-cell signaling in Drosophila

Heparan sulfate proteoglycans (HSPGs) are abundant molecules associated wit h the cell surface and extracellular matrix, and consist of a protein core to which heparan sulfate (HS) glycosaminoglycan (GAG) chains are attached. Although these molecules have been the focus of intense biochemical studies in vitro, their biological functions in vivo were unclear until recently. We have undertaken an in vivo functional study of HSPGs in Drosophila. Our studies, as well as others, demonstrate the critical roles of HSPGs in seve ral major signaling pathways, including ibroblast growth factor (FGF), Wnt, Hedgehog (Hh) and TGF-beta. Our results also suggest that specific HS GAG chain modifications, as well as specific HSPG protein cores, are involved i n specific signaling pathways. (C) 2000 Elsevier Science B.V./International Society of Matrix Biology. All rights reserved.