Understanding the crosstalk between spatially separated RNP granules during cellular stress responses

了解细胞应激反应过程中空间分离的 RNP 颗粒之间的串扰

• 批准号: BB/V014528/2
• 负责人: Nicolas Locker
• 金额: $ 42.15万
• 依托单位: The Pirbright Institute
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FV014528%2F2
• 关键词: Understanding; crosstalk; between; spatially; separated

Living organisms are constantly prompted to respond to the environment. This includes to changes in levels of nutrients, temperature, oxygen, invasion by pathogens and signals such as hormones. To pause and adapt, a key event is to limit protein synthesis, an energy hungry process. In addition, several signals are sent throughout the cell to communicate a state of emergency coordinating widespread changes. This allows for an overhaul of proteins in the cell to favour proteins that facilitate survival under the new conditions. According to textbooks, the main organising principle of a cell is the membrane with organelles such as the endoplasmic reticulum or mitochondria, wrapped in lipid bilayers. However, recent research is rethinking this model. Membraneless organelles allow the segregation of molecules, providing a new paradigm for cell biology. They form as a consequence of a change in the physical properties of their components, which now concentrate into specific regions of the cell. Because membraneless organelles can speed up reactions between their components or act as temporary storage, they are perfectly suited to contribute to rapid adaptation during stress. Proteins are encoded by RNA copies of genes called messenger RNA (mRNA). These mRNAs interact with a range of RNA binding proteins (RBPs) that control their fate. In response to stress and protein synthesis inhibition, mRNAs and RBPs bound to them, together with many other proteins, rapidly compartmentalise in the cytoplasm forming stress granules (SGs). Identified 35 years ago they are a paradigm for membraneless organelles. Several functions have been proposed for SGs. First, they help triage and store mRNAs to define which ones are needed to adapt to the new conditions and which are superfluous. Second, they are important for storing proteins that can send signals to trigger specific responses to the stress. Third, they are important in diseases; if anomalous they can contribute to diseases of the brain and they form part of our antiviral measures. Finally, our own findings suggest their assembly is important to trigger further waves of compartmentalisation, controlling the assembly of another membraneless organelle, the paraspeckle, in the nucleus. Despite this, major unsolved questions remain about how SGs function. They are part of a universal first line response to stress, yet it is apparent that SGs with distinct components and properties form depending on the nature of the stress. How and why specific components are selected, and how they drive specific functions, is currently poorly understood. Furthermore how SGs and other membraneless organelles like paraspeckles communicate, and the importance of these coordinated waves of compartmentalisation in normal and pathological conditions is unknown. Building on our expertise in studying SGs and paraspeckles, we now want to uncover how they contribute to cellular adaptation and specialised functions during stress. Our research program will comprehensively fingerprint SGs and paraspeckles under a range of different stresses to identify their components, interactions and functions. We will also define the molecular mechanisms by which SGs regulate the assembly of paraspeckles, uncovering how they communicate, and whether they regulate the assembly of other compartments. We will establish how SGs and paraspeckles contribute to the cellular defences against viruses and how the anomalous SGs associated with neurodegenerative diseases impact on paraspeckle-mediated responses in brain cells. Our current experience in isolating these organelles, and novel tools developed to image them are key for the success of these studies.Ultimately, the outcome of this work will advance our understanding of novel and fundamental aspects of cell biology and importantly relate this to pathological conditions.

不断提示生物体对环境做出反应。这包括养分水平的变化，温度，氧气，病原体的侵袭以及诸如激素之类的信号。要暂停和适应，关键事件是限制蛋白质合成，这是一个饥饿的过程。此外，在整个牢房中发送了几个信号，以传达紧急协调的状态，该状态是广泛的变化。这允许对细胞中的蛋白质进行大修，以有利于在新条件下促进生存的蛋白质。根据教科书的说法，细胞的主要组织原理是带有内质网或线粒体等细胞器的膜，包裹在脂质双层中。但是，最近的研究正在重新考虑该模型。无膜细胞器允许分离分子，为细胞生物学提供了新的范式。它们是由于其成分的物理特性的变化而形成的，该特性现在集中在细胞的特定区域中。由于无膜细胞器可以加快其组件之间的反应或充当临时存储，因此它们非常适合在压力期间快速适应。蛋白质由称为Messenger RNA（mRNA）的基因的RNA副本编码。这些mRNA与控制其命运的一系列RNA结合蛋白（RBP）相互作用。为了应对胁迫和蛋白质的合成抑制作用，与​​它们结合的mRNA和RBP与许多其他蛋白质结合，在细胞质形成应激颗粒（SGS）中迅速分裂。 35年前确定它们是无膜细胞器的范式。 SGS已提出了几种功能。首先，它们有助于分类和存储mRNA，以定义适应新条件并多余的需要哪些。其次，它们对于存储可以发送信号以触发压力的特定反应的蛋白质很重要。第三，它们在疾病中很重要。如果异常，它们可以为大脑的疾病做出贡献，并且它们构成了我们抗病毒措施的一部分。最后，我们自己的发现表明，它们的组装对于触发进一步的隔室化波很重要，控制了核中另一个无膜细胞器的组装。尽管如此，关于SGS的功能仍然存在主要的未解决问题。它们是对压力的普遍第一线反应的一部分，但是显然，具有不同组成部分和性质的SG取决于压力的性质。目前对选择特定组件的方式以及为什么选择特定的组件以及如何驱动特定功能的理解很少。此外，SGS和其他无膜细胞器（如羊皮纸）如何进行交流，以及在正常和病理条件下这些协调的隔室化波的重要性是未知的。在我们研究SG和拼贴方面的专业知识的基础上，我们现在想揭示它们在压力期间如何促进细胞适应和专业功能。我们的研究计划将在各种不同的压力下全面地指纹SG和拼贴，以识别其组成部分，相互作用和功能。我们还将定义SGS调节拼贴聚集，揭示它们的交流方式以及它们是否调节其他隔室的组装的分子机制。我们将建立SG和拼接如何有助于针对病毒的细胞防御，以及与神经退行性疾病相关的异常SG对脑细胞中拼虫介导的反应的影响。我们目前在隔离这些细胞器的经验以及为这些研究成像而开发的新工具是这些研究成功的关键。在文化中，这项工作的结果将促进我们对细胞生物学新颖和基本方面的理解，并重要地将其与病理条件有关。