Investigating the cellular role of a novel deubiquitylating enzyme in the DNA damage response

泛素是一种由76个氨基酸组成的多肽，可以在翻译后添加到靶蛋白上，以改变其在细胞中的功能和周转。顾名思义，它参与了一系列的细胞功能，从蛋白质降解到炎症信号和细胞对DNA损伤的反应。细胞可以将单个泛素分子附加到靶标上，也可以合成更长的泛素链，通过内部赖氨酸残基或N端伯胺连接。这产生了大量不同的信号，这些信号由不同的效应蛋白读取，驱动细胞内不同的功能结果。泛素结合和信号传递的一个关键方面是它是一个可逆的、高度动态的过程。与许多细胞过程一样，重要的是信号的存在和不存在之间的平衡。维持这种微妙平衡的酶类是去泛素化酶(DUBS)，它作用于切割或编辑蛋白质底物上的泛素信号。令人兴奋的是，研究界最近报道了一种名为ZUP1的新发现。该蛋白与现有的DUBS没有显著的同源性，构成了一类新的酶。有趣的是，ZUP1已被证明定位于DNA损伤的位置，并促进基因组稳定性和细胞活力，以响应遗传毒性压力。然而，ZUP1‘S在细胞内的功能仍不明确。该项目将使用尖端技术，如全基因组CRISPR-Cas9筛选，以确定ZUP1的功能途径，以及这如何促进细胞对DNA损伤的反应。这项研究符合DTP的机械性分子和细胞生物科学框架，并探索了细胞如何受到翻译后修饰的调节。

Ubiquitin is a 76-amino-acid polypeptide that can be appended to target proteins post-translationally to modify their function and turnover in cells. As the name suggests, it is involved in a wide array of cellular functions, ranging from protein degradation to inflammatory signaling and the cell's response to DNA damage. Cells can append a single ubiquitin molecule to a target, as well as synthesize longer chains of ubiquitin linked either via internal lysine residues or to the N-terminal primary amine. This creates a vast array of different signals that are read by distinct effector proteins driving different functional outcomes within a cell. A critical aspect of ubiquitin conjugation and signaling is that it is a reversible and highly dynamic process. As with many cellular processes it is the balance between presence and absence of a signal that is important. The enzyme class that maintains this delicate equilibrium are deubiquitylating enzymes (DUBs), which act to cleave or edit the ubiquitin signal from protein substrates. Excitingly, the research community has recently reported the discovery of a novel DUB named ZUP1. This protein does not share significant homology with existing DUBs and constitutes a new class of enzymes. Interestingly, ZUP1 has been shown to localize to sites of DNA damage and promote genome stability and cell viability in response to genotoxic stress. However, ZUP1's function within cells remains poorly defined. This project will use cutting edge techniques such as genome-wide CRISPR-Cas9 screening to identify the pathways that ZUP1 functions in and how this promotes the cellular response to DNA damage. This research fits within the mechanistic molecular and cellular bioscience framework of the DTP and explores how cells are regulated by post-translational modification.