A chemical approach to unravelling how peptide signals mediate cell-cell communication

化学探针是一种小分子工具，可以帮助解决历史上不均衡的生物学探索问题，刺激对以前被忽视的蛋白质的研究，并有助于新药物靶点的验证。我们体内的微生物细胞是人体细胞的十倍，但这些复杂的群落是如何运作的，我们还没有很好地了解。细胞之间通过一种小分子信号的化学语言进行交流、操纵和检测。在大多数情况下，我们不知道信号是如何被感知的，在活细胞中识别信号的蛋白质传感器是极具挑战性的。很少有化学探针直接用于揭示宿主-微生物的通讯，尽管在这个领域缺乏对信号如何与蛋白质靶点相互作用的分子理解。该项目将设计基于小分子肽信号的新型探针，并建立通用方法来分析它们与什么蛋白质相互作用。探针将包含一个战斗部（光反应性或内在反应性）来捕获受体和一个标签来附加用于分析的标签。在初步设计和验证探针之后，第二个目标将是设计新的特征，例如在探针内选择性切割连接，以精确确定探针在其蛋白质靶标上的结合位点。最后，标记化学将用于将化学功能转移到受体，以研究受体在细胞中的定位，识别新的信号和蛋白质相互作用的伙伴。因此，这项研究将建立一种使能技术，用于识别哪些蛋白质与活细胞中的肽信号相互作用。这种方法将广泛应用于化学生物学，以理解其他信号受体相互作用，并将阐明宿主-微生物通信的特定机制。这些新的生物学见解将有助于我们了解人类细胞如何与常驻和入侵微生物相互作用。这些社区的功能障碍与许多疾病有关，包括癌症、糖尿病和肥胖。该项目属于EPSRC化学生物学和生物化学领域，将提供有机和肽合成、生化方法和基于质谱的蛋白质组学方面的培训。

Chemical probes are small molecule tools that can help address the historically uneven exploration of biology, stimulating research into previously neglected proteins and contributing to the validation of new drug targets.There are ten times as many microbial cells as human cells in our bodies but how these complex communities function is not well understood. Cells communicate, manipulate and detect each other using a chemical language of small molecule signals. In most cases we do not know how signals are sensed, and identifying the protein sensors of signals in live cells is extremely challenging. Few chemical probes are directed at unravelling host-microbe communication, although molecular understanding of how signals interact with their protein targets is lacking in this field.This project will design novel probes based on small molecule peptide signals and establish general methods to analyse what proteins they interact with. Probes will incorporate a warhead (photoreactive or intrinsically reactive) to trap receptors and a tag to attach labels for analysis. Following initial design and validation of probes, the second objective will be the design of novel features such as selectively cleavable linkages within probes to enable precise determination of the binding sites of probes at their protein targets. Finally, labelling chemistry will be used to transfer chemical functionality to receptors, in order to study receptor localisation in the cell, identify new signals and protein interacting partners.This research will therefore establish an enabling technology for identifying which proteins interact with peptide signals in living cells. This approach will be widely applicable across chemical biology to understand other signal-receptor interactions and will also elucidate specific mechanisms of host-microbe communication. These new biological insights will contribute to our understanding of how human cells interact with resident and invading microbes. Dysfunction of these communities has been linked to numerous diseases, including cancer, diabetes and obesity.This project falls within the EPSRC area of Chemical biology and biological chemistry, and will provide training in organic and peptide synthesis, biochemical methods, and mass spectrometry-based proteomics.