A mechanoresponsive signalling pathway disassembles processing bodies

机械响应信号通路分解加工体

• 批准号: RGPIN-2022-03854
• 负责人: Corcoran, Jennifer
• 金额: $ 2.33万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761055
• 关键词: mechanoresponsive; signalling; pathway; disassembles; processing

A mechanoresponsive signalling pathway disassembles processing bodies Processing bodies (PBs) are cytoplasmic ribonucleoprotein granules that fundamentally regulate gene expression. PBs degrade or sequester mRNA to control what cellular transcripts are translated into protein. PBs are dynamic; they form and disassemble in response to various stimuli. Upon their disassembly, PB-localized mRNAs are relieved of repression, making PBs an important regulatory switch. However, the precise signals that control the `PB switch' are not well defined. With our NSERC-funded research program, we identified a novel mechanoresponsive signalling pathway that elicits PB disassembly, thereby contributing new knowledge to the fundamental understanding of PB control of gene expression. Cells are subject to constant mechanical stimulation that influences behaviour in a process called mechanotransduction. The conversion of external forces into intracellular biochemical signals requires formation thick actin bundles called actin stress fibres (SFs). These activate the mechanoresponsive transcriptional regulator, Yes-associated protein (YAP) to translocate to the nucleus where it regulates gene transcription. We previously showed that the viral KapB protein induced the formation of actin SFs and the disassembly of PBs. Using RNA silencing, we were not able to genetically separate these two phenotypes. Instead, we demonstrated that KapB induction of SFs was required for PB disassembly. Moreover, silencing YAP eliminated KapB-mediated PB disassembly. A biochemically active version of YAP or the exposure of cells to mechanical forces known to activate YAP also caused PB disassembly. These data indicated that YAP was necessary for KapB-mediated PB disassembly, sufficient for PB disassembly and revealed a connection between a mechanoresponsive transcription activator and the regulation of PBs. In a continuation of our NSERC-funded research program, we will further define the signals between mechanical forces, YAP activation and PB disassembly. We propose three specific aims: 1) Characterize mechanical signals that lead to PB disassembly, 2) Identify how mechanical signals elicited from within the cell by KapB influence YAP activation, 3) Elucidate the mechanism of YAP-mediated PB disassembly Impact and Significance: Our studies advance the fundamental understanding of the role of YAP mechanotransduction. We demonstrated that PBs are regulated by mechanical signalling events that alter actin SFs and require the mechanoresponsive transcription factor, YAP. KapB activates, from within the cell, a pathway that links cell shape to post-transcriptional gene regulation via cytoplasmic PBs. This is important because many other stimuli induce actin SFs, actin contractility, changes to cell shape, and active YAP and our work predicts that these stimuli would also cause PB disassembly to modulate cellular gene expression.

加工体是细胞质内的核糖核蛋白颗粒，从根本上调节基因的表达。PB降解或隔离mRNA以控制哪些细胞转录物被翻译成蛋白质。PB是动态的;它们响应于各种刺激而形成和分解。在它们的分解后，PB定位的mRNA被解除抑制，使PB成为重要的调节开关。然而，控制“PB开关”的精确信号没有很好地定义。通过我们的NSERC资助的研究计划，我们确定了一种新的机械反应信号通路，该通路可以促进PB的分解，从而为PB控制基因表达的基本理解提供了新的知识。 细胞受到持续的机械刺激，在一个称为机械转导的过程中影响行为。将外力转化为细胞内生化信号需要形成厚的肌动蛋白束，称为肌动蛋白应力纤维（SF）。这些激活机械应答转录调节因子，是相关蛋白（雅普）易位到细胞核，在那里它调节基因转录。我们以前表明，病毒KapB蛋白诱导肌动蛋白SF的形成和PB的解体。使用RNA沉默，我们无法从遗传上区分这两种表型。相反，我们证明，KapB诱导的SF是PB拆卸所需的。此外，沉默雅普消除了KapB介导的PB分解。一种具有生物化学活性的雅普或细胞暴露于已知可激活雅普的机械力也会导致PB分解。这些数据表明，雅普是必要的KapB介导的PB解体，足以PB解体，并揭示了机械应答转录激活剂和PB的调节之间的连接。在我们的NSERC资助的研究计划的延续，我们将进一步定义机械力，雅普激活和PB拆卸之间的信号。我们提出了三个具体目标：1）表征导致PB分解的机械信号，2）确定KapB从细胞内引发的机械信号如何影响雅普激活，3）阐明雅普介导的PB分解的机制。我们证明，PB的调节，改变肌动蛋白SF的机械信号事件，并需要机械应答转录因子，雅普。KapB从细胞内激活一条途径，该途径通过细胞质PB将细胞形状与转录后基因调控联系起来。这是很重要的，因为许多其他刺激诱导肌动蛋白SF，肌动蛋白收缩性，细胞形状的变化，和积极的雅普和我们的工作预测，这些刺激也会导致PB拆卸调节细胞基因表达。