KSR and regulators of RAS signaling in C elegans

线虫中 KSR 和 RAS 信号传导的调节因子

• 批准号: 7255646
• 负责人: Meera Sundaram
• 金额: $ 27.99万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7255646
• 关键词: Affect; Animals; Binding; Binding Proteins; Biological; Biological Models; Bypass; Caenorhabditis elegans; Cell membrane; Cells; Development; Developmental Process; Duct (organ) structure; Endocytosis; Enhancers; Ensure; Funding; Genes; Genetic; Goals; Human; MEKs; Malignant Neoplasms; Mediating; Membrane; Modeling; Pathway interactions; Pattern; Phosphorylation; Phosphotransferases; Play; Process; Proteins; RNA Interference; Regulation; Research; Research Personnel; Role; Scaffolding Protein; Signal Transduction; Signaling Protein; Site; Specificity; Testing; Therapeutic; Tissues; Ubiquitin-Conjugating Enzymes; Ubiquitination; base; design; in vivo; inhibitor/antagonist; intracellular protein transport; mutant; paralogous gene; prevent; protein transport; rab GTP-Binding Proteins; raf Kinases; receptor; response; scaffold; trafficking; tumorigenesis

DESCRIPTION (provided by applicant): The Ras-stimulated Raf/MEK/ERK kinase cascade plays critical roles in normal animal development and cancer. Multiple poorly understood mechanisms ensure that this cascade is active only when and where it should be. Increasing evidence suggests that compartmentalization of signaling proteins by scaffolds is an important component of such regulation. Our research uses C. elegans as a genetic model system to identify new regulators of Raf/MEK/ERK signaling and understand how they function. During the previous funding period (04/01/00 to 3/31/05), we demonstrated the essential and widespread role of the scaffold KSR in MEK/ERK activation, and we showed that the scaffold CNK promotes a specific step of Raf activation. We also identified multiple other conserved, but previously unstudied, gene products that cooperate with KSR-1 to promote certain downstream responses to this signaling cascade. In the next funding period, we will focus on several sets of these gene products to understand how compartmentalization of signaling proteins controls signal propagation and specificity. In Aim 1, we will test if inherent functional differences between the KSR-1 and KSR-2 paralogs contribute to tissue-specific responses. In Aim 2, we will determine the role of the scaffold CNK-1 and its binding partner KIC-1 in Raf activation and localization. Membrane translocation and endocytosis are key steps in Raf activation and de-activation, and we will test the model that CNK-1 and KIC-1 are involved in these processes. In Aim 3, we will determine the role of a conserved ubiquitin conjugating (E2) enzyme in Ras signaling and scaffold function. We will test the model that this E2 regulates trafficking and localization of the KSR or CNK scaffolds, or of other signaling proteins, and we will identify the mechanism by which it acts. In Aim 4, we will continue both forward genetic and RNAi-based screens for new Ras pathway regulators, and choose for further study those mostly likely to function with KSR, CNK and/or our E2 protein. Our studies are expected to reveal new aspects of Ras pathway regulation and clarify the mechanisms and biological relevance of signaling compartmentalization. Aberrant signaling by Ras or Raf is 1 of the most frequent causes of human cancers. In the long term, a detailed understanding of Raf/MEK/ERK regulation will allow the rational design of therapeutic approaches to treat such cancers.

描述（由申请人提供）：Ras 刺激的 Raf/MEK/ERK 激酶级联在正常动物发育和癌症中发挥关键作用。多种鲜为人知的机制确保这种级联仅在其应有的时间和地点才起作用。越来越多的证据表明，支架对信号蛋白的区室化是这种调节的重要组成部分。我们的研究使用线虫作为遗传模型系统来识别 Raf/MEK/ERK 信号传导的新调节因子并了解它们的功能。在之前的资助期间（04/01/00至3/31/05），我们证明了支架KSR在MEK/ERK激活中的重要和广泛的作用，并且我们表明支架CNK促进Raf激活的特定步骤。我们还鉴定了多个其他保守但之前未研究过的基因产物，它们与 KSR-1 合作促进对该信号级联的某些下游反应。在下一个资助期间，我们将重点关注这些基因产物的几组，以了解信号蛋白的区室化如何控制信号传播和特异性。在目标 1 中，我们将测试 KSR-1 和 KSR-2 旁系同源物之间固有的功能差异是否有助于组织特异性反应。在目标 2 中，我们将确定支架 CNK-1 及其结合伙伴 KIC-1 在 Raf 激活和定位中的作用。膜易位和内吞作用是Raf激活和失活的关键步骤，我们将测试CNK-1和KIC-1参与这些过程的模型。在目标 3 中，我们将确定保守的泛素缀合 (E2) 酶在 Ras 信号传导和支架功能中的作用。我们将测试该 E2 调节 KSR 或 CNK 支架或其他信号蛋白的运输和定位的模型，并且我们将确定其作用机制。在目标 4 中，我们将继续基于正向遗传和 RNAi 筛选新的 Ras 通路调节剂，并选择那些最有可能与 KSR、CNK 和/或我们的 E2 蛋白一起发挥作用的调节剂进行进一步研究。我们的研究有望揭示 Ras 通路调控的新方面，并阐明信号区室化的机制和生物学相关性。 Ras 或 Raf 信号传导异常是人类癌症的最常见原因之一。从长远来看，对 Raf/MEK/ERK 调节的详细了解将有助于合理设计治疗此类癌症的治疗方法。