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Scribble(Scrib)是富含亮氨酸重复序列及PDZ结构域蛋白(LAP)家族的一员,以脚手架蛋白的方式与多种分子相结合并整合多种信号通路协同发挥作用。β-catenin是一种多功能蛋白质,在介导细胞粘附及信号转导中起中心分子作用。为研究Scrib与β-catenin间是否存在联系及何种联系,我们做了一系列实验。研究发现,如果HEK293/HEK293T细胞中过表达Scrib,β-catenin的转录活性报告基因LEF-1-1uciferase的活性则显著减弱;而如果HEK293/HEK293T细胞中稳定下调Scrib,LEF-1-luciferase的活性则显著增强。表明Scrib可抑制β-catenin的转录活性。我们同时利用免疫共沉淀(Co-IP)实验发现Scrib与β-catenin存在特异结合作用。另外,细胞组分分离实验表明HEK293/HEK293T细胞中稳定下调Scrib,细胞中β-catenin蛋白总量不变,而胞浆及胞核内β-catenin量增多即表明Scrib可抑制β-catenin的入核。本研究在分子机制上表明Scrib可通过与β-catenin的结合,抑制β-catenin入核,从而影响β-catenin的下游调控基因。
Scribble (Scrib) is a member of a family of leucine-rich repeats and PDZ-domain proteins (LAPs) that act as scaffolding proteins in conjunction with multiple molecules and integrate multiple signaling pathways. β-catenin is a multifunctional protein that plays a central role in mediating cell adhesion and signal transduction. In order to investigate whether Scrib and β-catenin are involved in or not, we conducted a series of experiments. The study found that if Scrib was overexpressed in HEK293 / HEK293T cells, the activity of LEF-1-1uciferase, a transcriptional reporter for β-catenin, was significantly attenuated; whereas, if Scrib was consistently down-regulated in HEK293 / HEK293T cells, LEF-1-luciferase activity Is significantly enhanced. Scribed inhibition of β-catenin transcriptional activity. We also use co-immunoprecipitation (Co-IP) experiments found that Scrib and β-catenin specific binding. In addition, the cell component separation experiments showed that the stable down-regulation of Scrib in HEK293 / HEK293T cells, the total amount of β-catenin protein in the cells unchanged, while the cytoplasmic and nuclear β-catenin increased that Scrib inhibited β-catenin into nuclear. The molecular mechanism of this study shows that Scrib inhibits the entry of β-catenin into the nucleus by binding to β-catenin, thereby affecting the downstream regulatory genes of β-catenin.