Glypicans, a small multigene family of glycosylphosphatidylinositol （GPI）-linked proteoglycans, play a pivotal role in growth factor signaling. GPC-1, a member of the glypican family, is expressed in various cell types including neurons, smooth and skeletal muscle cells, keratinocytes, osteoblasts, Schwann cells, immature dendritic cells, tumor cells, and tumor-associated vascular endothelial cells. The glypican-related integral membrane proteoglycan family （GRIPS） consists of core proteins anchored to the plasma membrane via a glycosyl phosphatidylinositol linkage. These proteins are implicated in the regulation of cell division and growth control.