The surfaces of eukaryotic cells and microorganisms (bacteria, viruses) are very complex structures composed of various lipids and proteins, which in most cases are modified by a variety of carbohydrates. Most of these carbohydrates on the cell surface are directed to the outside media where they are involved in cellular or parasite-cellular interactions. For example, the T-cell surface glycoprotein CD4 has an important role in immune cell interactions: infection of T- cells by HIV is mediated by the HIV glycoprotein 120 that binds to the CD4 glycoprotein1,2. Covalent modifications of proteins with oligosaccharides occur during one of the major post-translational modification processes, glycosylation. Glycosylation processes, mediated by various glycotransferases, start immediately during protein biosynthesis in the endoplasmic reticulum and continue in the Golgi apparatus, and plasma membrane. Current biochemical methods to study protein glycosylation rely on the chemical and structural analyses of proteins isolated from the cells. However, these methods, like mass spectroscopy and NMR, while very powerful in the information they provide, lack applicability for studies in vivo. To achieve a more complete understanding of how glycosylation occurs in live cells as well as how glycosylation of proteins is involved in various signaling events, scientists need new methodologies. One of the approaches to analyze protein glycosylation is to create a genetically encoded biosensor for specific glycoproteins or for monitoring the specific glycosylation events in the cells.
|Original language||English (US)|
|Publication status||Published - Mar 9 2005|