Title : Characterization of glycosylation
sites of the
epidermal growth factor receptor
Abstract :
- The epidermal growth factor receptor is a transmembrane glycoprotein that mediates the cellular responses to epidermal growth factor ( EGF ) and transforming growth factor-alpha ( TGF-alpha )
- In this study of the human EGF receptor naturally expressed in A431 cells, the glycosylation sites of the full-length, membrane-bound receptor and of a secreted form of the receptor were characterized by mass spectrometry
- Our data show that the naturally expressed human EGF receptor is fully glycosylated on eight of the 11 canonical sites ; two of the sites are not glycosylated, and one is partially glycosylated, a pattern of site-usage similar but not identical to those reported for the recombinant human EGF receptor heterologously expressed in Chinese hamster ovary cells
- We also confirm the partial glycosylation of an atypical NNC site first identified in the receptor expressed in Chinese hamster ovary cells
- We show that an additional canonical site in the secreted form of the receptor is fully glycosylated
- While the pattern of glycosylation is the same for the sites shared by the full-length and the secreted forms of the receptor , the oligosaccharides of the full-length receptor are more extensively processed
- Finally, we provide evidence that in addition to the known secreted form of the receptor , a proteolytic cleavage product of the receptor corresponding to the full extracytoplasmic, ligand-binding domain is present in the conditioned medium