A glycolipid that functions as a protein modifier and has a core structure composed of a phosphatidylinositol (PI) bound, through a carbohydrate linker comprised of glucosamine and three mannose residues, to an ethanolamine phosphate (EtNP), which can be covalently linked to the carboxy-terminal amino acid of the modified protein. Glycosylphosphatidylinositol moieties anchor extracellular proteins to the cell surface by insertion of the PI fatty acid chains into the membrane bilayer.

Compounds containing carbohydrate or glycosyl groups linked to phosphatidylinositols. They anchor GPI-LINKED PROTEINS or polysaccharides to cell membranes.