Cellular Stress Response Mechanisms

项目摘要 这项提案的目的是确定细胞如何在面对不利的环境条件下优化生存。 条件拟议的研究是一个长期计划的延续，旨在了解如何 应激信号通路包括eIF 2 α的磷酸化、4 EBP-1的低磷酸化和 血管生成素诱导的tRNA切割重新编程蛋白质翻译并诱导应激颗粒的组装 (SGs)来调节细胞存活。我们的中心假设是，这些信号通路调节 以可用于治疗癌症的方式表达促生长和促存活蛋白 和神经退行性疾病。这是基于我们的发现，ANG选择性地切割tRNA， 产生生物活性片段（即，使用多种机制来抑制翻译起始， 诱导SG组装。我们还发现，不同的应激刺激产生不同的组成SG 可以促进或抑制细胞存活。这项研究的基本原理是，一旦我们知道 这些信号通路如何重新编程蛋白质翻译来调节细胞存活，我们将能够利用 这些事件来治疗癌症和神经退行性疾病。我们将测试我们的中心假设， 阻碍该领域进展的主要知识差距。其中包括：（1）对角色的理解 RNA在SG组装成核中的作用，2）了解SG的组成和功能 促进或抑制细胞存活，3）了解SG成核的机制， 蛋白G3 BP 1/2促进SG装配，4）阐明了tiRNA抑制复合物的组成， 其靶转录物的鉴定，5）理解tiRNAs如何选择性地调节 携带5 '末端寡嘧啶基序的mRNA，6）对G-四链体结构的理解 调节tiRNA功能，以及7）阐明单个tiRNA抑制的不同机制 翻译起始这项研究的贡献将是确定tiRNAs和SGs 调节参与癌症和神经变性疾病发病机制的细胞的存活。这 贡献是重要的，因为它提供了药理学发展的分子基础 预防应激介导的肿瘤生长或运动神经元死亡的策略。拟议的研究是 创新，因为它专注于这些压力反应程序的下游效应器，并试图 确定可以开发成新疗法的分子靶点。

Project Summary The objective of this proposal is to determine how cells optimize survival in the face of adverse environmental conditions. The proposed research is a continuation of a long-standing program designed to understand how stress signaling pathways including phosphorylation of eIF2α, hypophosphorylation of 4EBP-1, and angiogenin-induced tRNA cleavage re-program protein translation and induce the assembly of stress granules (SGs) to modulate cell survival. Our central hypothesis is that these signaling pathways modulate the expression of pro-growth and pro-survival proteins in ways that can be exploited for the treatment of cancer and neurodegenerative disease. This is based upon our findings that ANG selectively cleaves tRNAs to produce bioactive fragments (i.e., tiRNAs) that use multiple mechanisms to inhibit translation initiation and induce SG assembly. We have also found that different stress stimuli produce compositionally distinct SGs that can either promote or inhibit cell survival. The rationale for the proposed research is that, once we know how these signaling pathways re-program protein translation to modulate cell survival, we will be able to exploit these events to treat cancer and neurodegenerative disease. We will test our central hypothesis by addressing key knowledge gaps that are holding back progress in the field. These include: 1) an understanding of the role played by RNA in the nucleation of SG assembly, 2) an understanding of the composition and function of SGs that either promote or inhibit cell survival, 3) an understanding of the mechanism by which the SG nucleating proteins G3BP1/2 promote SG assembly, 4) elucidation of the composition of tiRNA inhibitory complexes and the identify of their target transcripts, 5) an understanding of how tiRNAs selectively modulate the translation of mRNAs bearing 5'-terminal oligopyrimidine motifs, 6) an understanding of how G-quadruplex structures modulate tiRNA function, and 7) elucidation of the different mechanisms by which individual tiRNAs inhibit translation initiation. The contribution of the proposed research will be to determine how tiRNAs and SGs modulate the survival of cells involved in the pathogenesis of cancer and neurodegenerative disease. This contribution is significant because it provides a molecular basis for the development of pharmacologic strategies to prevent stress-mediated tumor growth or motor neuron death. The proposed research is innovative because it focuses on the downstream effectors of these stress response programs and attempts to identify molecular targets that can be developed into novel therapeutics.