Rab21通过促进EGFR降解负调控EGF激活的MAPK信号通路

发布时间：2018-01-11 00:07

本文关键词：Rab21通过促进EGFR降解负调控EGF激活的MAPK信号通路　出处：《清华大学》2012年硕士论文　论文类型：学位论文

更多相关文章： Rab21 EGFR 降解内吞 MAPK信号通路

【摘要】：表皮生长因子受体（EGFR或者ErbB1）属于ErbB受体家族，是一类具有酪氨酸激酶活性的膜受体，，它在细胞的增殖、分化、迁移、粘附及凋亡等多种重要的生命进程中起重要作用。因此EGFR受体必须受到精确的调控以确保体内生理活动的正常进行，而配体介导的细胞表面受体快速内吞即是EGFR信号转导的一种重要调控机制。在这一过程中，多种磷酸化蛋白、泛素化蛋白和内吞体膜上的蛋白协同作用，已有研究表明Rab蛋白作为一类通过招募特异效应分子控制囊泡识别转运的小G蛋白能够参与到EGFR的内吞转运中。为了进一步阐明Rab蛋白通过内吞作用调控信号传导的分子机制，本论文通过在HEK293T细胞和HeLa细胞中瞬时转染表达Rab21蛋白的质粒和一系列生物化学和分子生物学的研究方法，深入探究了小G蛋白Rab21对EGFR内吞和降解及其下游信号通路的影响。免疫共沉淀实验证明Rab21和EGFR之间存在相互作用，同时，细胞免疫荧光染色实验说明Rab21与内吞的EGFR共定位。另外，细胞免疫荧光实验证明Rab21能够改变细胞内EGFR的分布状态，促进EGFR内吞。进一步研究揭示Rab21能够促进EGF非依赖和EGF依赖两种模式下的EGFR降解。此外，磷酸化ERK水平的检测和荧光素酶报告实验均表明Rab21能够下调EGF介导的MAPK信号通路。综上所述，Rab21能够通过促进EGFR降解和内吞抑制EGF介导的MAPK信号通路。这为深刻理解配体介导的受体内吞这一经典负反馈调控过程的分子机制提供了有力证据。
[Abstract]:Epidermal growth factor receptor (EGFR) or ErbB1) belongs to the ErbB receptor family. It is a kind of membrane receptor with tyrosine kinase activity. It proliferates, differentiates and migrates in cells. Adhesion and apoptosis play an important role in many important life processes. Therefore, EGFR receptors must be precisely regulated to ensure normal physiological activities in vivo. Ligand-mediated rapid endocytosis of cell surface receptors is an important regulatory mechanism of EGFR signal transduction. In this process, many phosphorylated proteins, ubiquitin proteins and proteins on endocytosis membrane act synergistically. It has been shown that Rab protein can participate in the endocytosis of EGFR as a kind of small G protein which can control vesicle recognition and transport by recruiting specific effector molecules. In order to further elucidate the molecular mechanism of Rab protein regulating signal transduction through endocytosis. In this paper, the transient transfection of plasmid expressing Rab21 protein in HEK293T cells and HeLa cells and a series of biochemical and molecular biological methods were carried out. The effects of small G protein Rab21 on the endocytosis and degradation of EGFR and its downstream signaling pathway were investigated. The results of immunoprecipitation showed that there was an interaction between Rab21 and EGFR, and at the same time. Cellular immunofluorescence staining showed that Rab21 was colocated with endocytosis EGFR. In addition, cellular immunofluorescence assay showed that Rab21 could change the distribution of EGFR in cells. Promote EGFR endocytosis. Further study revealed that Rab21 can promote the degradation of EGFR in EGF independent and EGF dependent modes. The detection of phosphorylated ERK and luciferase report showed that Rab21 could down-regulate the MAPK signaling pathway mediated by EGF. To sum up. Rab21 can inhibit MAPK signaling pathway mediated by EGF by promoting EGFR degradation and endocytosis. This provides a profound understanding of the molecular mechanism of ligand-mediated endocytosis, a classical negative feedback regulation process. There is strong evidence.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R341

【共引文献】