受体型蛋白质酪氨酸磷酸酶RPTPα的N-糖基化鉴定及相关功能研究

早期的研究揭示受体型蛋白质酪氨酸磷酸酶RPTPα可以特异去磷酸化c-Src蛋白的C-末端527位酪氨酸残基，激活癌基因c-Src激酶活性，诱发细胞恶性转化，但其自身的调控机制少有研究。我们前期的研究证实膜蛋白RPTPα存在N-糖基化修饰 (N-glycosylation), 初步的实验结果揭示该修饰对生理条件下RPTPα的膜定位，蛋白稳定性及发挥磷酸酶活性等都有影响，近期我们又鉴定出Asn36和Asn104是RPTPα糖基化修饰位点。本课题拟在此基础上，通过分子生物学、细胞生物学实验及动物模型等深入研究RPTPα N-糖基化的生物学特性及对RPTPα—c-Src相关信号通路的调控；并尝试建立RPTPα的去N-糖链偶联免疫分析方法，助力临床诊疗研究。

RPTPα, one receptor protein tyrosine phosphatase, functions as an activator of c-Src kinase by specially dephosphorylating the tyrosine 527 located near the C-terminus of c-Src, and thus is considered to be an oncogenic gene. However, little is known about regulation of RPTPα expression. Here our preliminary data show that RPTPα could be modified with N-glycosylation, which modification of RPTPα is closed related to its characteristics such as membrane location, protein stability and phosphatase activity. Recently, Asn36 and Asn104, located at the extracellular domain, are identified to be the N-glycosylated sites of RPTPα. In this project, we try to elucidate the biological characters of this N-glycosylation and the functions of this modification on RPTPα—c-Src signaling. In addition, we plan to develop a practical method for detection of RPTPα by deglycosylation linked with immunoassay for accurate prediction of clinical outcome.