Probing life-and-death switches using "designer" p53

蛋白质是控制大多数生物过程的分子机器。其中，一种名为p53的蛋白质起到了抗癌的作用，它指示癌细胞在繁殖之前自我毁灭。因此，p53的功能障碍是大多数人类癌症的先决条件。因此，了解p53单独或与其他蛋白伙伴共同作用的分子机制是很重要的。在分子水平上，p53接受来自细胞的大量应激信号，这些应激信号以共价生化信号的形式沉积在p53上，即所谓的翻译后修饰。这些信号形成了一种编码，然后p53将其整合到一个定义的细胞反应中，从“一切如常”到有针对性的修复过程，一直到细胞死亡协议的启动。然而，p53及其蛋白伙伴如何解码翻译后修饰仍然是个谜。该提案旨在通过确定特定的翻译后修饰如何改变p53与其蛋白质伙伴之间的功能相互作用来揭示p53如何做出这种生死决定。我们之所以能够实现这一目标，是因为我们开发了化学工具，使我们能够合成携带特定修饰的“设计p53”。在合成新版本的“设计师p53”后，我们的目标是在试管中重建生化信号过程，使我们能够在受控环境下测量翻译后修饰的效果。具体来说，我们的目标是解决p53修饰如何作为分子对接平台连接已知和新的蛋白质伙伴，并将这些相互作用转化为进一步的生化信号。通过这种方式，我们将阐明p53如何作为一种分子信号整合装置，为新的定量见解奠定基础，以了解其作为肿瘤抑制因子的作用。

Proteins are molecular machines that control most biological processes. Among them, a protein called p53 acts as a safeguard against cancer in that it instructs cancers cells to self-destruct before they can multiply. Accordingly, malfunction of p53 is a prerequisite for most human cancers. It is therefore important to understand the molecular mechanism by which p53 operates, alone and in conjunction with other protein partners. At the molecular level, p53 receives a multitude of stress signals from cells that are deposited onto p53 in the form of covalent biochemical signals, so-called post-translational modifications. These signals form a type of code which p53 then integrates into a defined cellular response ranging from "business as usual" and targeted repair processes all the way to the initiation of cell death protocols. However, how exactly p53 and its protein partners decode post-translational modifications remains enigmatic. This proposal aims to unravel how p53 makes such life-and-death decisions by determining how specific post-translational modifications change the functional interactions between p53 and its protein partners. We are able to achieve this goal because we have developed chemical tools that allows us to synthesise "designer p53" carrying defined modifications. Upon synthesising new versions of "designer p53", we aim to reconstitute biochemical signalling processes in the test tube, allowing us to measure the effect of post-translational modifications under controlled circumstances. Specifically, we aim to address how p53 modifications act as molecular docking platforms to connect with known and new protein partners and convert these interactions into further biochemical signals. In this way, we will illuminate how p53 acts as a molecular signal integration device which sets the foundation for new quantitative insights into its action as a tumour suppressor.