Investigating reciprocal regulation of the cytoskeleton and protein translation machinery

细胞骨架作为一个动态的内部框架在细胞中起着至关重要的作用。它赋予细胞形状、细胞内运输的路径、物理支持、表面受体的组织以及对外部机械力敏感的相关信号因子。蛋白质合成是一个高度复杂的过程，涉及到被称为核糖体的巨大分子机器将mRNAs翻译成多肽。此外，还需要一套称为tRNAs的接头样核酸和一系列不同的翻译因子来协调新蛋白质的制造。人们越来越认识到，这两种细胞现象并不是孤立地工作的，而是协同工作的。细胞骨架似乎为蛋白质翻译机制的定位提供了一个支架，包括真核启动因子、核糖体、mRNAs和氨基酰-tRNA合成酶。反过来，据报道，这些因素中的一些在组织细胞骨架的肌动蛋白细丝方面发挥了作用。此外，这个丝状网络的生化破坏已被证明显著干扰蛋白质的合成。然而，尽管有这些联系，这两个复杂的细胞机制的交叉调节仍然处于探索之中。这个项目旨在扩大我们对细胞骨架和蛋白质翻译之间的相互关系的了解。我们将把注意力集中在我们的初步数据显示与细胞骨架结合的一个关键的蛋白质翻译启动因子上。重要的是，当使用一种名为RNA干扰(RNAi)的技术显著降低细胞中这一因子的水平时，我们发现细胞骨架的行为发生了惊人的变化，但令人惊讶的是，没有影响组成细胞骨架的蛋白质的总水平，如肌动蛋白。然而，我们发现当细胞暴露在机械力下时，这个翻译因子对于结合到细胞骨架的关键信号枢纽上的局部蛋白质翻译是重要的。我们将使用包括细胞生物学、质谱学和最新的下一代测序技术在内的一系列生物学方法来了解这种蛋白质转换因子如何调节细胞骨架，以及如何调节机械诱导的蛋白质合成。我们相信，这项工作也将阐明解释细胞骨架和蛋白质翻译机制如何以及为什么相互交叉调节的一般原理。从长远来看，这项工作的基本发现可能会对神经系统疾病和癌症的治疗产生影响。

The cytoskeleton plays an essential role in the cell as a dynamic internal framework. It imparts cell shape, routeways for intra-cellular transport, physical support, and organisation of surface receptors and related signaling factors that are sensitive to external mechanical forces. Protein synthesis is a highly complex process involving the translation of mRNAs into polypeptides by massive molecular machines known as ribosomes. In addition, a suite of adaptor-like nucleic acids called tRNAs, and a host of different translation factors are required to coordinate the manufacture of new proteins. There is growing appreciation that these two cellular phenomena do not work in isolation but rather in concert. The cytoskeleton appears to provide a scaffold for the positioning of the protein translation machinery including eukaryotic initiation factors, ribosomes, mRNAs, and aminoacyl-tRNA synthetases. In return, some of these factors have been reported to play role in organising the actin protein filaments of the cytoskeleton. Further, biochemical disruption of this filamentous network has been shown to significantly interfere with protein synthesis. However, despite these connections the cross regulation of these two complex cellular machineries remains under explored. This project seeks to expand our knowledge of the inter-relationship between the cytoskeleton and protein translation. We will focus our attention on a key protein translation initiation factor that our preliminary data shows binds to the cytoskeleton. Importantly, when levels of this factor are significantly reduced in the cell using a technique called RNA interference (RNAi) we find there is a striking change in the behaviour of the cytoskeleton, but surprisingly without affecting the total levels of the proteins that make up the cytoskeleton such as actin. However, we find this translation factor is important for localised protein translation at key signaling hubs bound to the cytoskeleton when the cells are exposed to mechanical force. We will use a range of biological approaches including cell biology, mass spectrometry and the latest next-generation sequencing techniques to deconvolute how this protein translation factor regulates the cytoskeleton, and also modulates mechanically-induced protein synthesis. We believe this work will also shed light on general principles that explain how and why the cytoskeleton and protein translation machinery cross-regulate each other. In the long term, fundamental findings from this work may have implications for the treatment of diseases including nervous system disorders and cancer.