Regulation and Function of Integrated Stress Response

综合应激反应的调节和功能

• 批准号: 10398838
• 负责人: RONALD C WEK
• 金额: $ 38.64万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10398838
• 关键词: Address; Bar Codes; Biochemistry; Cell Survival; Cells; Collection; Couples; Diabetes Mellitus; Diagnosis; Disease; Gene Expression; Gene Expression Profile; Genes; Genetic Translation; Genomics; Goals; Guanosine Triphosphate; Knowledge; Malignant Neoplasms; Messenger RNA; Metabolic Diseases; Molecular; Molecular and Cellular Biology; Nutrient; Obesity; Open Reading Frames; Pathway interactions; Pattern; Peptide Initiation Factors; Phosphorylation; Process; Protein Biosynthesis; Protein Kinase; Proteolysis; Proteome; Regulation; Repression; Research; Resources; Ribosomes; Scanning; Signal Pathway; Stress; Technology; Therapeutic; Transcription Coactivator; Translating; Translation Initiation; Translations; biological adaptation to stress; biomarker development; cell type; innovation; insight; irradiation; neuropathology; non-alcoholic fatty liver disease; programs; protein degradation; protein folding; repaired

Cells adapt to extrinsic and intrinsic stresses by rapidly adjusting the rates of protein synthesis. An important mechanism for this translational control involves phosphorylation of eIF2, a translation initiator factor that couples with GTP and delivers Met-tRNAi(Met) to ribosomes. For example during nutrient limitation, GCN2 (EIF2AK4) phosphorylation of eIF2 (eIF2-P) blocks the exchange of eIF2-GDP to eIF2-GTP, thus reducing global translation initiation which allows cells to conserve resources and reprogram gene expression. GCN2 is also activated by UV-B irradiation, disruption in protein degradation, and during differentiation of certain cell types. Coincident with repression of global protein synthesis, eIF2-P enhances translation of select mRNAs, such as ATF4, encoding a transcriptional activator of genes subject to the Integrated Stress Response (ISR). Translational control in the ISR involves upstream open reading frames (uORFs) that serve as “bar codes” for scanning ribosomes to delineate mRNAs that are preferentially translated from those that are repressed by or indifferent to eIF2-P. It is important to emphasize that a majority of mammalian mRNAs contain uORFs, so their presence alone is not sufficient to direct preferential translation. Rather we determined that the sequence and context of uORFs are critical determinants for preferential translation in the ISR. Furthermore, while diverse stresses induce the ISR, our research suggests that the ISR implementation of translational control provides for different programs of gene expression that are best suited for cell adaptation to a given stress condition. Our hypothesis is that GCN2 is activated by diverse cell perturbations, facilitating patterns of gene expression that are tailored to adapt to a specific stress condition. In this proposal we address important gaps in our knowledge of the ISR. Using innovative concepts and technologies that feature biochemistry, molecular and cellular biology, and genomic and structural perspectives, we will address three fundamental ISR questions. 1) What are the mechanisms by which GCN2 recognizes diverse stress conditions and invokes translational control? 2) How does eIF2-P induce different patterns of mRNA translation, whereby some mRNAs are preferentially translated, whereas others are tolerant of or repressed by eIF2-P? Finally, 3) How does translational control invoked by eIF2-P, combined with stress-induced proteolysis, change the proteome and signaling pathways that direct cell survival? Completion of the proposed studies will garner new insights into the mechanisms by which diverse stresses activate GCN2 and the processes by which ribosomes differentially translate mRNAs. These studies will also provide an understanding for how the ISR contributes to the progression of stress-related diseases, including diabetes and related metabolic disorders, neuropathologies, and cancer, with the promise of developing new strategies for diagnosis and treatment.

细胞通过快速调节蛋白质合成速率来适应外部和内在应激。一个 这种翻译控制的重要机制涉及EIF2的磷酸化，这是一种翻译引发剂因子 与GTP并将Met-troNAi（MET）伴侣伴侣到核糖体。例如，在养分限制期间，GCN2 （EIF2AK4）EIF2（EIF2-P）的磷酸化阻止EIF2-GDP与EIF2-GTP的交换，从而减少 全局翻译启动，允许细胞保存资源和重编程基因表达。 GCN2是 也通过UV-B辐射，蛋白质降解的破坏以及某些细胞分化而激活 类型。 EIF2-P与全球蛋白质合成的表达一致，增强了精选mRNA的翻译， 例如ATF4，编码受综合应力反应（ISR）的基因转录激活因子。 ISR中的翻译控制涉及上游开放式阅读框（UORF），这些框架是“条形码” 扫描核糖体以描述优先翻译的mRNA 对EIF2-p无动于衷。重要的是要强调，大多数哺乳动物mRNA都包含Uorfs，因此 仅它们的存在就不足以指导首选翻译。相反，我们确定了序列 UORF的上下文是ISR中首选翻译的关键决定剂。此外， 潜水员强调的是ISR，我们的研究表明，ISR的实施转化控制 提供不同的基因表达程序，最适合细胞适应给定的压力 健康）状况。我们的假设是GCN2被多种细胞扰动激活，支持基因的模式 量身定制以适应特定应力条件的表达。在此提案中，我们解决了重要差距 根据我们对ISR的了解。使用具有生物化学的创新概念和技术，分子 和细胞生物学以及基因组和结构观点，我们将解决三个基本ISR 问题。 1）GCN2识别潜水压力状况并引用的机制是什么 翻译控制？ 2）EIF2-P如何影响mRNA翻译的不同模式，其中一些 优选地翻译了mRNA，而其他mRNA则宽容或通过EIF2-P进行了耐受？最后，3）如何 EIF2-p调用的翻译对照，结合了应力诱导的蛋白水解，改变了蛋白质组 和直接细胞存活的信号通路？拟议研究的完成将获得新的见解 进入各种应力激活GCN2的机制和核糖体的过程 差异翻译mRNA。这些研究还将对ISR如何贡献 与压力相关疾病的进展，包括糖尿病和相关代谢性疾病， 神经病理学和癌症，有望制定新的诊断和治疗策略。