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

Ras-Raf-MAPK通路通过从细胞膜传递信号来调节许多生理过程。 将受体结合到细胞核和细胞质靶点，以协调细胞对各种因素的反应，例如 生长、压力、存活和炎症。该途径的异常导致异常生长和增殖， 在很多情况下，会导致恶性转化高频率的激活Ras突变发现于 各种人类癌症，以及Raf在许多生理过程中的作用， Ras-Raf-MAPK通路是用于各种癌症、炎症和其它疾病药物开发的主要靶点 c-Raf-1是一种细胞原癌基因，也存在于转化病毒中，是Ras的主要效应子， MAPK的活化是Ras-MAPK级联反应中不可缺少的重要组成部分。虽然许多实验室 尽管科学家们一直在研究Raf的调控，但这种高度复杂的机制的许多方面仍然未知。发表 申请人的工作和本提案中提出的初步结果有助于阐明其中的几个方面 提供了一种抑制Raf活性的新途径。本申请的目的是 进一步了解Raf调控，重点是Ras和磷酸化在 Raf调节，并基于有效的体外Raf抑制剂开发有用的体内Raf抑制剂， 在本申请中描述。这些目标将通过以下三个具体目标来实现： 施舍：1.描述Ras在Raf-1激活过程中的作用。将注意区分 Ras在将Raf募集到膜上和置换14-3-3中的作用之间，以及Ras-Ras和 活化过程中的Raf-Raf二聚化。2.确定Raf-1$471和T481位点在大鼠中的作用 规则和功能。这一目标将通过审查471美元和T481美元的规定来实现 磷酸化和评估其取代和磷酸化的功能意义。3. 表征Raf-1抑制剂肽抑制Raf的潜在机制，并鉴定肽递送 允许在体内抑制细胞Raf-1的方法。建议的研究将加强我们对Raf的了解 通过提供Ras作用的分子细节和Raf中新鉴定的Raf磷酸化位点， activation.此外，该研究为开发体内Raf抑制剂提供了前景， 除了是一种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