Regulation of c-Raf-1 by Ras and Growth Factors

Ras-Raf-MAPK信号通路通过传递膜信号来调节许多生理过程。 结合核受体和细胞质靶标，协调细胞对各种因素的反应，如 生长、压力、生存和炎症。该途径中的异常会导致异常的生长和增殖， 在许多情况下，会导致恶变。发现激活RAS突变的高频率 各种人类癌症，再加上Raf在许多生理过程中被充分证明的作用，使得 Ras-Raf-MAPK通路是各种癌症、炎症和其他疾病药物开发的主要靶点 C-Raf-1，一种在转化病毒中也发现的细胞原癌基因，是RAS的主要效应因子 MAPK被激活，是RAS-MAPK信号通路中不可缺少的重要组成部分。尽管许多实验室 尽管人们一直在研究Raf的调控，但这一高度复杂的机制的许多方面仍不清楚。已出版 申请者的工作和本提案中提出的初步结果有助于解开其中的几个方面 为抑制Raf活性提供了一种新的途径。本申请的目标是 进一步了解RAF的调节，重点是RAS和磷酸化在体内的具体作用 Raf调节，并基于体外有效的Raf抑制剂开发一种有用的体内Raf抑制剂， 在本申请中描述的。这些目标将通过追求以下三个具体目标来实现 ALMS：1.描述RAS在Raf-1激活过程中的作用。我们将注意区分 RAS在膜上募集Raf和置换14-3-3的作用与RAS-RAS和Ras-Ras的作用 Raf-Raf在活化过程中的二聚化。2.确定Raf-1$471和T481位点在大鼠体内的作用 规范和功能。这一目标将通过审查471美元和T481的监管来实现 并通过评价它们的取代和磷酸化的功能意义。3. 鉴定Raf-1抑制肽抑制Raf的机制，并鉴定多肽递送 允许在体内抑制细胞Raf-1的方法。拟议的研究将加深我们对Raf的了解 通过提供RAS的作用和新发现的Raf磷酸化位点的分子细节进行调控 激活。此外，这项拟议的研究为开发体内Raf抑制剂提供了前景，该抑制剂在 除了是一个非常有用的研究工具外，还将为开发治疗药物提供基础 涉及细胞过度增殖的疾病，如癌症和炎症。 我

The Ras-Raf-MAPK pathway regulates many physiological processes by transmitting signals from membrane- bound receptors to nuclear and cytoplasmic targets that coordinate cellular response to a variety of factors, such as growth, stress, survival and inflammation. Aberrations in this pathway result in abnormal growth and proliferation, and in many cases, cause malignant transformation. The high frequency of activating Ras mutations found in various human cancers, together with the well-documented role of Raf in numerous physiological processes, make the Ras-Raf-MAPK pathway a prime target for drug development for various cancers, inflammation and other aliments, c-Raf-1, a cellular protooncogene also found in transforming viruses, is the primary Ras effector for MAPK activation and is a major and indispensable part of the Ras-MAPK cascade. Although many laboratories have been studying Raf regulation, many aspects of this highly complex mechanism remain unknown. Published work by the applicant and preliminary results presented in this proposal help to unravel several of these aspects and provide a novel approach for inhibiting Raf activity. The objectives of the present application are to further the understanding of Raf regulation, focusing on specific roles of Ras and phosphorylation in Raf regulation, and to develop a useful in vivo Raf inhibitor based on a potent in vitro Raf inhibitor, described in this application. These objectives will be accomplished by pursuing the following three specific alms: 1. Characterize the role of Ras in the Raf-1 activation process. Attention will be given to distinguishing between the role of Ras in recruiting Raf to the membrane and displacing 14-3-3, and to the role of Ras-Ras and Raf-Raf dimerization in the activation process. 2. Determine the role of Raf-1 $471 and T481 sites in Rat regulation and function. This aim will be accomplished by examining the regulation of $471 and T481 phosphorylation and by evaluating the functional significance of their substitution and phosphorylation. 3. Characterize the mechanism underlying Raf inhibition by the Raf-1 inhibitor peptide, and identify peptide-delivery methods allowing inhibition of cellular Raf-1 in vivo. The proposed study will enhance our understanding of Raf regulation by providing molecular details on the role of Ras and newly identified Raf phosphorylation sites in Raf activation. In addition, the proposed study offers the prospect for developing an in vivo Raf inhibitor, which in addition to being a highly useful research tool, would provide a basis for developing therapeutic agents for diseases involving excessive cell proliferation such as cancer and inflammation. I