Unraveling the mechanism by which Rps26-deficient ribosomes form to support the stress response

揭示 Rps26 缺陷核糖体形成支持应激反应的机制

基本信息

批准号：
10226865
负责人：
Jason Yoon-Mo Yang
金额：
$ 5.01万
依托单位：
SCRIPPS FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2022-04-04
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10226865
关键词：
Alanine Amino Acids Binding Cells Congenital Abnormality Data Destinations Development Diamond-Blackfan anemia Disease Dissociation Ensure Etiology Excision Failure Genetic Translation Heterogeneity In Vitro Individual Life Lifting Link Malignant Neoplasms Marrow Messenger RNA Modification Molecular Chaperones Mutation Organism Outcome Pathway interactions Phenotype Phosphorylation Phosphotransferases Physiologic pulse Physiological Population Positioning Attribute Post-Translational Protein Processing Production Protein Biosynthesis Protein Deficiency Proteins Quality Control Recombinants Reporting Ribosomal Proteins Ribosomal RNA Ribosomes Risk Role Series Sodium Chloride Specificity Stress Testing Translating Translations Work Yeasts biological adaptation to stress bone cancer cell cost design experimental study human disease in vivo interest macromolecule mimetics novel null mutation preference programs proteostasis repaired response

项目摘要

Project Summary/Abstract Recently ribosome subpopulations that differ in their composition, lacking individual ribosomal proteins (RPs), or containing specific modifications have garnered a lot of interest. In the case of RP content, multiple studies have shown that ribosomes lacking specific RPs are present in cells, including ribosomes deficient in Rps26. While their physiological relevance remains unclear in most cases, the Karbstein lab has recently demonstrated that ribosomes lacking Rps26 are produced specifically under high salt and pH stress to enable the preferential translation of mRNAs encoding proteins from the Hog1 and Rim101 pathways that are required for the response to these stresses. This change in mRNA specificity between Rps26-containing and deficient ribosomes arises from the recognition of the -4 position of the Kozak sequence by Rps26, thereby supporting the translation of well-translated mRNAs by Rps26-containing ribosomes in rich medium, and the translation of specific mRNAs in the Hog1 and Rim101 pathways by Rps26-deficient ribosomes that are formed under these stresses. What remains unknown is how Rps26-deficient ribosomes form under high salt and high pH stress. My preliminary results suggest Rps26-deficient ribosomes are produced by release of Rps26 from pre-existing ribosomes. Therefore, I will further dissect in more detail the mechanism that leads to the production of Rps26- deficient ribosomes, exploring the role of the Rps26-specific chaperone Tsr2 in delivering to and extracting Rps26 from ribosomes (Aim1), and testing which posttranslational modifications regulate this pathway (Aim2). Next, I will test if Rps26 is (re-) incorporated into Rps26-deficient ribosomes, to allow for a rapid switch in mRNA-specificity without the costs of re-building new ribosomes, or whether instead these ribosomes are degraded (Aim3). Together, these experiments will clarify how Rps26-deficient ribosomes form under stress. In addition to further expanding on this novel paradigm of stress-induced production of a specific ribosome population, the results will also have implications for the development of diseases linked to Rps26-deficiency, such as Diamond- Blackfan anemia. Because the etiology of 10-15% of all cases remains unknown, and is not linked to RP- deficiency, it is possible that overactivation of pathways leading to the release of RPs such as Rps26 might be responsible for a subset of cases, similar to the subset of cases caused by deficiency of the Rps26-chaperone Tsr2. Furthermore, ribosomes lacking individual RPs, including Rps26, are produced in cancer cells, where they are associated with poor outcomes. Thus, this work will also help delineate how cancer cells modulate the translational machinery to subvert translation to its purposes.

项目概要/摘要最近，核糖体亚群的组成不同，缺乏单独的核糖体蛋白（RP），或包含特定修饰引起了很多兴趣。就 RP 内容而言，多项研究研究表明，细胞中存在缺乏特定 RP 的核糖体，包括缺乏 Rps26 的核糖体。虽然在大多数情况下它们的生理相关性仍不清楚，但卡布斯坦实验室最近发现证明缺乏 Rps26 的核糖体是在高盐和 pH 胁迫下专门产生的，从而能够编码来自 Hog1 和 Rim101 途径所需蛋白质的 mRNA 的优先翻译来应对这些压力。含有 Rps26 的和缺乏 Rps26 的 mRNA 特异性的这种变化核糖体源自 Rps26 对 Kozak 序列的 -4 位点的识别，从而支持含有 Rps26 的核糖体在丰富培养基中翻译良好翻译的 mRNA，以及 Hog1 和 Rim101 途径中由 Rps26 缺陷核糖体形成的特定 mRNA 压力。目前尚不清楚的是 Rps26 缺陷核糖体在高盐和高 pH 胁迫下如何形成。我的初步结果表明 Rps26 缺陷核糖体是通过从预先存在的 Rps26 中释放而产生的核糖体。因此，我将进一步更详细地剖析导致Rps26产生的机制—— 缺陷核糖体，探索 Rps26 特异性伴侣 Tsr2 在递送和提取中的作用来自核糖体的 Rps26 (Aim1)，并测试哪些翻译后修饰调节该通路 (Aim2)。接下来，我将测试 Rps26 是否（重新）整合到 Rps26 缺陷核糖体中，以允许快速切换 mRNA 特异性，无需重建新核糖体的成本，或者这些核糖体是否是降级（目标 3）。总之，这些实验将阐明 Rps26 缺陷核糖体在压力下如何形成。除了进一步扩展了这种应激诱导产生特定核糖体群体的新范式，结果还将对与 Rps26 缺乏相关的疾病的发展产生影响，例如 Diamond- 黑扇贫血。因为所有病例中 10-15% 的病因仍不清楚，且与 RP- 无关缺陷，可能是导致 RP（例如 Rps26）释放的途径过度激活负责部分病例，类似于 Rps26 伴侣缺陷引起的病例子集 Tsr2。此外，缺乏单个 RP（包括 Rps26）的核糖体是在癌细胞中产生的，其中它们与不良结果相关。因此，这项工作也将有助于描述癌细胞如何调节翻译机器颠覆翻译的目的。