Regulatory Roles of Cellular Cholesterol

项目描述 胆固醇是哺乳动物质膜的主要脂质成分。胆固醇异常 水平已牵连在几种疾病，包括心血管疾病，尼曼-皮克 C型疾病和阿尔茨海默氏病，等等;然而，不知道胆固醇如何 浓度与细胞过程有关。特别是，胆固醇直接参与细胞 通过与胞质蛋白质的特异性相互作用的调节尚未被彻底研究。 我们最近发现，胆固醇特异性地与各种细胞溶质支架相互作用， 蛋白质并调节其多种细胞信号传导活动。这一重要发现不仅 表明胆固醇可以直接与主要的细胞调节蛋白相互作用， 提供了优秀的系统来研究膜胆固醇水平之间的直接相关性， 和细胞活动。我们还开发了一种新的荧光成像技术， 膜脂质的实时定量。总的来说，我们发现了一类新的胆固醇 结合蛋白和我们新的定量脂质成像技术为我们提供了一个独特的， 这是一个前所未有的机会，可以系统地研究胆固醇调节 不同的细胞过程。我们的主要假设是血浆中的局部胆固醇水平 膜充当各种细胞过程的活化阈值，包括Wnt信号传导。 这项研究的主要目的是调查不同的潜在机制， 胆固醇介导的细胞调节。具体而言，我们建议（1）确定胆固醇如何 通过与支架蛋白Dvl的特异性相互作用调节Wnt信号传导，（2）建立稳健的 和通用的细胞胆固醇原位定量成像，和（3）确定如何在细胞内的变化， 质膜中的局部胆固醇水平介导经典Wnt信号传导。

PROJECT DESCRIPTION Cholesterol is a major lipid component of the mammalian plasma membrane. Abnormal cholesterol levels have been implicated in several diseases, including cardiovascular diseases, Niemman-Pick type C disease, and Alzheimer's disease, among others; however it is not know how the cholesterol concentration is linked to cellular processes. In particular, the direct involvement of cholesterol in cell regulation through specific interactions with cytosolic proteins has not been thoroughly investigated. We have recently discovered that cholesterol specifically interacts with various cytosolic scaffold proteins and regulate their diverse cellular signaling activities. This important finding not only demonstrates that cholesterol can directly interact with major cellular regulatory proteins but also offers excellent systems to investigate the direct correlation between membrane cholesterol levels and cellular activities. We also developed a new fluorescence imaging technology for accurate in situ real-time quantification of membrane lipids. Collectively, our discovery of a new class of cholesterol binding proteins and our new quantitative lipid imaging technology provide us a unique and unprecedented opportunity to systematically study the mechanisms by which cholesterol regulates diverse cellular processes. Our main hypothesis is that the local cholesterol level in the plasma membrane serves as an activation threshold for various cellular processes, including Wnt signaling. The primary objective of this proposed research is to investigate the mechanisms underlying diverse cholesterol-mediated cell regulation. Specifically, we propose to (1) determine how cholesterol regulates Wnt signaling through specific interaction with a scaffold protein, Dvl, (2) establish robust and versatile in situ quantitative imaging of cellular cholesterol, and (3) determine how changes in the local cholesterol level in the plasma membrane mediate canonical Wnt signaling.