Identification of ω-sites of Glycosylphosphatidylinositol Anchored Proteins

Unique and complex post-translational modifications are present in the outer leaflet of the plasma membrane. Glycosylphosphatidylinositol (GPI) anchoring is essential for the expression of several outer membrane proteins on the cell surface. A common GPI anchor structure is constituted by glycan moiety, lipid moiety, phosphate and ethanolamine. GPI-anchored proteins (GPI-APs) are observed among eukaryotic species. Abnormal GPI anchoring of proteins is thought to cause various diseases such as paroxysmal nocturnal hemoglobinuria. Recently, many inherited GPI deficiencies (IGDs) have been reported to cause epilepsy, mental retardation, coarse facial features, and multiple organ anomalies. Diseases caused by abnormal GPI anchoring will probably continue to increase, because it is still unknown how many causative genes of IGDs are present. Therefore, in order to study these diseases, the analytical methods of GPI-APs will become important in the future. To date, many methods have been developed for analysis of GPI- APs. In this review, we attempt to summarize the present knowledge about comprehensive analytical methods of GPI-APs and introduce briefly some GPI anchor-related diseases.