Cellular Stress Response Mechanisms

项目摘要 这项建议的目标是确定细胞如何在不利的环境中优化生存。 条件。这项拟议的研究是一项长期计划的延续，旨在了解 胁迫信号通路包括eif2α的磷酸化，4EBP-1的低磷酸化，以及 血管生成素诱导的tRNA裂解重编程蛋白翻译并诱导应激颗粒的组装 (SGS)调节细胞存活。我们的中心假设是，这些信号通路调节 促进生长和促进生存的蛋白在癌症治疗中的表达 和神经退行性疾病。这是基于我们的发现，Ang选择性地将tRNA切割到 产生生物活性片段(即，tiRNAs)，它使用多种机制来抑制翻译启动和 诱导SG组装。我们还发现，不同的应激刺激会产生成分不同的SGS 既可以促进细胞存活，也可以抑制细胞存活。提出这项研究的理由是，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生存，我们将能够利用 这些事件用于治疗癌症和神经退行性疾病。我们将通过解决以下问题来测试我们的中心假设 阻碍该领域进展的关键知识差距。这些包括：1)对角色的理解 RNA在SG组装成核中的作用，2)对SGS组成和功能的理解 促进或抑制细胞存活，3)对SG成核机制的理解 蛋白质G3BP1/2促进SG组装，4)阐明tiRNA抑制复合体的组成和 他们的目标转录本的识别，5)理解tiRNAs如何选择性地调节 含有5‘-末端寡嘧啶基序的mRNAs，6)对G-四链结构的理解 调节tiRNA的功能，以及7)阐明单个tiRNA抑制的不同机制 翻译启蒙。拟议研究的贡献将是确定tiRNAs和SGS如何 调节参与癌症和神经退行性疾病发病机制的细胞的存活。这 贡献是重大的，因为它为药理学的发展提供了分子基础 防止应激诱导的肿瘤生长或运动神经元死亡的策略。拟议的研究是 创新是因为它专注于这些应激反应计划的下游效应器，并试图 确定可被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.