Characterization of glycosylation sites of the epidermal growth factor receptor
Characterization of glycosylation sites of the epidermal growth factor receptor
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DOI：
10.1021/bi027101p
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发表时间：
2003-05-13
期刊：
影响因子：
2.9
通讯作者：
Staros, JV
中科院分区：
文献类型：
--
作者：
Zhen, YJ;Caprioli, RM;Staros, JV
表皮生长因子受体是介导细胞对表皮生长因子（EGF）和转化生长因子-α（TGF-α）的应答的跨膜糖蛋白。在A431细胞中天然表达的人EGF受体的这项研究中，通过质谱法表征了全长膜结合受体和分泌形式受体的糖基化位点。我们的数据表明，自然表达的人EGF受体是完全糖基化的11个典型的网站上的8个，两个网站是不糖基化，一个是部分糖基化，网站使用的模式相似，但不相同的重组人EGF受体异源表达在中国仓鼠卵巢细胞。我们还证实了在中国仓鼠卵巢细胞中表达的受体中首次发现的非典型NNC位点的部分糖基化。我们表明，一个额外的典型网站的分泌形式的受体是完全糖基化。虽然糖基化的模式对于受体的全长和分泌形式所共有的位点是相同的，但全长受体的寡糖被更广泛地加工。最后，我们提供的证据表明，除了已知的分泌形式的受体，蛋白水解裂解产物的受体对应于完整的胞质外，配体结合域存在于条件培养基中。
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.