Coordinated regulation of signaling events for insulin biosynthesis and secretion

摘要： 这个项目的目标是破译分子信号机制，以控制 胰岛素的生物合成和分泌，目前的重点是解剖功能 Shp2酪氨酸磷酸酶在协调细胞信号级联中的作用。虽然 胰腺细胞衰竭是所有形式的糖尿病的关键组成部分，分子 细胞功能障碍的基础还知之甚少。这主要是因为 对于介导葡萄糖和胰岛素信号的细胞质成分知之甚少。 ？-细胞。Shp2是一种胞质酪氨酸磷酸酶，具有两个SH2结构域，即 与信号通路的调节和协调有关。特别是，Shp2拥有 已被证明在体外促进胰岛素刺激的ERK激活，尽管 Shp2在胰岛素信号转导中的生理意义尚不清楚。在最近 研究中，我们成功地创造了一个条件性Shp2基因敲除等位基因Shp2flx，在 小鼠，这使我们能够研究特定细胞类型或特定细胞中的特定Shp2功能 体内的组织。我们已经产生了Shp2在成熟细胞或在 PDX1+胰腺前体细胞，并将这些新的小鼠模型表征为 检验Shp2作用于协调和控制强弱的工作假设 在细胞中协调胰岛素生物合成和分泌的几个信号通路。 作为体内基因打靶方法的补充，我们还将使用siRNA- 利用基因敲除技术破译分子信号转导机制 在细胞中。我们的具体目标是：1)确定Shp2在细胞中的生理作用 功能与血糖动态平衡；2)探讨Shp2的分子机制 3)探讨Shp2在胰腺发育和生长发育中的作用。 --细胞再生。拟议中的实验的成功完成将填补一个空白 在我们对细胞内细胞质信号事件的协调调节的知识中， 甚至可能导致一种关于葡萄糖细胞功能调节的新范式 动态平衡也参与了2型糖尿病的发病机制。

Summary: The goal of this project is to decipher molecular signaling mechanisms for control of insulin biosynthesis and secretion, and the immediate focus is on dissecting the function of Shp2 tyrosine phosphatase in orchestrating signaling cascades in ¿ cells. Although pancreatic ¿ cell failure is a critical component in all forms of diabetes, the molecular basis underlying ¿ cell dysfunction is poorly understood. This is mainly because that little is known for the cytoplasmic components mediating glucose and insulin signals in ¿-cells. Shp2 is a cytoplasmic tyrosine phosphatase with two SH2 domains that is implicated in regulation and coordination of signaling pathways. In particular, Shp2 has been shown to promote insulin-stimulated Erk activation in vitro, although the physiological significance of Shp2 function in insulin signaling is unclear. In recent studies, we have successfully created a conditional Shp2 knockout allele, Shp2flox, in mice, which allows us to investigate specific Shp2 functions in a specific cell type or tissue in vivo. We have generated mutant mice with Shp2 deleted in mature ¿-cells or in Pdx1+ pancreatic precursor cells, and will characterize these novel mouse models to test the working hypothesis that Shp2 acts to coordinate and control the strength of several signaling pathways in orchestrating insulin biosynthesis and secretion in ¿-cells. In complement with the gene targeting approach in vivo, we will also use siRNA- mediated gene knockdown technique to decipher the molecular signaling mechanisms in ¿ cells. Our specific aims are: 1) to determine the physiological role of Shp2 in ¿-cell function and glucose homeostasis; 2) to dissect the molecular mechanism for Shp2 action in ¿-cells; and 3) to investigate the Shp2 function in pancreatic development and ¿-cell regeneration. Successful completion of the proposed experiments will fill in a gap in our knowledge for coordinated regulation of cytoplasmic signaling events in ¿-cells, and may even lead to a new paradigm on regulation of ¿-cell functions in glucose homeostasis and also in pathogenesis of type 2 diabetes.