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/V014528/1
• 负责人: Nicolas Locker
• 金额: $ 56.32万
• 依托单位: University of Surrey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FV014528%2F1
• 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.

活着的有机体不断地受到激励，对环境做出反应。这包括营养水平、温度、氧气、病原体入侵和激素等信号的变化。为了暂停和适应，一个关键的事件是限制蛋白质合成，这是一个耗能的过程。此外，几个信号在整个细胞内发送，以传达协调大范围变化的紧急状态。这允许对细胞中的蛋白质进行彻底改造，以有利于促进在新条件下生存的蛋白质。根据教科书，细胞的主要组织原理是含有内质网或线粒体等细胞器的膜，包裹在脂双层中。然而，最近的研究正在重新思考这一模式。无膜细胞器允许分子分离，为细胞生物学提供了一种新的范式。它们的形成是因为它们的成分的物理性质发生了变化，现在这些成分集中在细胞的特定区域。由于无膜细胞器可以加速其成分之间的反应或充当临时存储，它们非常适合在应激期间帮助快速适应。蛋白质是由称为信使RNA(信使RNA)的基因的RNA拷贝编码的。这些mRNAs与一系列控制其命运的RNA结合蛋白(RBPs)相互作用。作为对应激和蛋白质合成抑制的反应，与它们结合的mRNAs和RBPs与许多其他蛋白质一起，在细胞质中迅速区域化，形成应激颗粒(SGS)。35年前发现的它们是无膜细胞器的典范。已经为SGS提出了几个功能。首先，他们帮助对mRNA进行分类和存储，以确定哪些是适应新条件所需的，哪些是多余的。其次，它们对于储存蛋白质很重要，这些蛋白质可以发送信号来触发对压力的特定反应。第三，它们在疾病中很重要；如果异常，它们可能会导致大脑疾病，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区间化浪潮非常重要，控制着另一种无膜细胞器--副视斑--在细胞核中的组装。尽管如此，关于SGS如何运作的主要悬而未决的问题仍然存在。它们是对压力的普遍第一线反应的一部分，但很明显，具有不同成分和性质的SGS取决于压力的性质。如何以及为什么选择特定的组件，以及它们如何驱动特定的功能，目前还知之甚少。此外，SGS和其他无膜细胞器如副细胞器如何沟通，以及这些协调的区隔波在正常和病理条件下的重要性尚不清楚。在我们研究SGS和Paraspeckles的专业知识的基础上，我们现在想要揭示它们是如何在压力下对细胞适应和特殊功能做出贡献的。我们的研究计划将在一系列不同的压力下对SGS和Paraspeckles进行全面的指纹分析，以确定它们的组成、相互作用和功能。我们还将定义SGS调控副脑室组装的分子机制，揭示它们是如何沟通的，以及它们是否调控其他隔室的组装。我们将确定SGS和Paraspeckles如何促进细胞对病毒的防御，以及与神经退行性疾病相关的异常SGS如何影响脑细胞中Paraspeckles介导的反应。我们目前分离这些细胞器的经验和开发的新工具是这些研究成功的关键。最终，这项工作的结果将促进我们对细胞生物学新的和基本的方面的理解，并将其与病理条件重要地联系起来。

项目成果

The Batten disease protein CLN3 is important for stress granules dynamics and translational activity.

• DOI: 10.1016/j.jbc.2023.104649
• 发表时间: 2023-05
• 期刊: JOURNAL OF BIOLOGICAL CHEMISTRY
• 影响因子: 4.8
• 作者: Relton, Emily L.;Roth, Nicolas J.;Yasa, Seda;Kaleem, Abuzar;Hermey, Guido;Minnis, Christopher J.;Mole, Sara E.;Shelkovnikova, Tatyana;Lefrancois, Stephane;McCormick, Peter J.;Locker, Nicolas
• 通讯作者: Locker, Nicolas