DROSOPHILA SYNDECAN - CONSERVATION OF A CELL-SURFACE HEPARAN-SULFATE PROTEOGLYCAN

In mammals, cell-surface heparan sulfate is required for the action of basic fibroblast growth factor, fibronectin, antithrombin III, as wel l as other effectors. The syndecans, a gene family of four transmembra ne proteoglycans that participates in these interactions, are the majo r source of this heparan sulfate. Based on the conserved transmembrane and cytoplasmic domains of the mammalian syndecans, a single syndecan -like gene was detected and localized in the Drosophila genome. As in mammals, Drosophila syndecan is a heparan sulfate proteoglycan express ed at the cell surface that can be shed from cultured cells. The singl e Drosophila syndecan is expressed in embryonic tissues that correspon d with those tissues in mammals that express distinct members of the s yndecan family predominantly. Conservation of this class of molecules suggests that Drosophila, like mammals, uses cell-surface heparan sulf ate as a receptor or coreceptor for extracellular effector molecules.