Proteoglycans
The major cell membrane HSPGs are the transmembrane syndecans and the glycosylphosphatidylinositol (GPI) anchored glypicans. Other minor forms of membrane HSPG include betaglycan and the V-3 isoform of CD44 present on keratinocytes and activated monocytes.
In the extracellular matrix, especially basement membranes, the multi-domain perlecan, agrin and collagen XVIII core proteins are the main HS-bearing species.
Read more about this topic: Heparan Sulfate