GPI anchor
A GPI anchor (phosphatidyl-inositol glycane) is a common modification of the C terminus of membrane attached proteins in which a phosphatidyl inositol moiety is linked through glucosamine and mannose to a phosphoryl ethanolamine residue that is linked to the C terminal amino acid of the protein by its amino group.Glypiation is the sole means of attachment of such proteins to the membrane.
Defects of GPI anchors occur in the rare disease paroxysmal nocturnal hemoglobinuria.