Six blind men and the elephant--the many faces of heparan sulfate

摘要

Did you hear the one about the chem.- ist, the biochemist, the molecular bi- ologist, the physiologist, the physician- scientist, and the clinical oncologist? They went out to learn about a mysterious and complex creature called a heparan sulfate (HS) proteoglycan. Their interest was piqued by an intriguing paper in this issue of PNAS (1) with the title "Tumor Cell Surface Heparan Sulfate as Cryptic Pro- moters or Inhibitors of Tumor Growth and Metastasis." They came upon a knowledgeable female scientist who told them that HS chains belonged to a class of long acidic sugar chains called glycosami- noglycans (GAGs), which usually are at- tached to cell surfaces via a core protein (2). The combination of one or more HS chains and a core protein is called an HS proteoglycan (Fig. 1).