Glycosylation

GPI Anchor

Glycosylphosphatidylinisotol (GPI)-anchored proteins are membrane-bound proteins found throughout the animal kingdom. Their functionality ranges from enzymatic to antigenic and adhesion. GPI anchored proteins are linked at their carboxy-terminus through a phosphodiester linkage of phosphoethanolamine to a trimannosyl-non-acetylated glucosamine (Man3-GlcN) core. The reducing end of the GlcN is linked through another phosphodiester linkage to phosphatidylinositol (PI). The PI is then anchored to the cell membrane through its hydrophobic region. The Mann3-GlcN oligosaccharide core may undergo various modifications during secretion from the cell.1,2,3Phospholipase C, Phosphatidylinositol-specific (PLC-PI). This enzyme specifically hydrolyzes the phosphodiester bond of phosphatidylinositol to form free 1,2-diacylglycerol and glycopeptide-bound inositol-cyclic-1,2-phosphate.

References:

  1. Brooks, S.A., et . al., Functional and Molecular Glycobiology, pp. 221-226, Bios Scientific Pub. (Oxford UK 2002).
  2. Hart, G.W., in Essentials of Glycobiology, pp. 131-143, Cold Spring Harbor Press, (Cold Spring Harbor, NY 1999).
  3. Ferguson, M. A. J., in Glycobiology: A Practical Approach, Fukuda, M. and Kobata, A. (Eds), pp. 349-350, IRL/Oxford Univ. Press (Oxford UK 1993).