Identification of a new membrane-bound heparan sulphate proteoglycan.
The morphological changes that occur during intestinal development have been extensively described, but the molecular basis of these changes is largely unknown. As a result of our efforts to identify molecules that play a role in intestinal morphogenesis during development, we have previously isolated a cDNA that is developmentally regulated in the intestine. This cDNA, named OCI-5, was recently shown to have 20-25% identity at the protein-sequence level with glypican and cerebroglycan, two heparan sulphate proteoglycans (HSPG) that are attached to the cell membrane by a glycosyl-phosphatidylinositol (GPI) anchor. Here we provide experimental evidence indicating that OCI-5 is also a GPI-linked HSPG. We demonstrate this by showing that OCI-5 can be labelled with radioactive sulphate and can be digested by heparitinase, but not by chondroitinase. We also show that treatment with phosphatidylinositol-specific phospholipase C releases OCI-5 from the cell surface of COS cells transfected with an OCI-5 expression vector. The identification of OCI-5 as a GPI-linked HSPG confirms that this proteoglycan belongs to the same family of HSPGs that include glypican and cerebroglycan.
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry* / Q000187:drug effects; D002522:Chlorocebus aethiops; D004247:DNA / Q000032:analysis; D005455:Fluorescent Antibody Technique; D017261:Glycosylphosphatidylinositols / Q000032:analysis*; D006497:Heparan Sulfate / Q000032:analysis*; D007668:Kidney / Q000737:chemistry / Q000166:cytology; D008562:Membrane Glycoproteins / Q000032:analysis*; D009693:Nucleic Acid Hybridization; D011133:Polysaccharide-Lyases / Q000494:pharmacology; D011509:Proteoglycans / Q000032:analysis*; D014162:Transfection; D010738:Type C Phospholipases / Q000494:pharmacology
D004247:DNA; D017261:Glycosylphosphatidylinositols; D006497:Heparan Sulfate; D008562:Membrane Glycoproteins; D011133:Polysaccharide-Lyases; D011509:Proteoglycans; D010738:Type C Phospholipases; C021349:heparitinsulfate lyase