How the proteasome works: resolving a critical new level of regulation

蛋白酶体是所有真核生物中重要的细胞调节剂。它们通过分解旧的、受损的或不再需要的蛋白质来参与大多数蛋白质的周转。它们还对特定蛋白质进行高度调控的去除，这些蛋白质向细胞分裂、应激反应和染色质维护等重要且多样化的事件发出信号。尽管经过 30 年的研究，蛋白酶体功能的许多基本方面仍未得到充分表征。我们最近发现二价阳离子对蛋白酶体的调节达到了意想不到的新水平，这挑战了我们目前对蛋白酶体如何工作的理解。我想利用我们的新数据来明确描述蛋白酶体在细胞内的工作原理。为此，我将使用基于电子显微镜的结构分析，以及生物化学和生物物理方法，详细可视化它们如何受二价阳离子调节以及它们如何识别和处理要降解的蛋白质。由于蛋白酶体是一种关键的细胞调节剂，了解其基本工作机制将对整个生物科学产生广泛的影响。拟议工作的成果有可能有助于阐明癌症进展、神经退行性变和衰老等疾病的关键机制，其中涉及蛋白酶体功能障碍和钙失调，对广泛的受益者产生影响。蛋白酶体是治疗癌症等疾病的公认药物靶点，因此除了提高基础知识之外，该提案还有可能为药物发现和开发的进一步发展做出贡献。

Proteasomes are essential cell regulators in all eukaryotes. They are involved in the turnover of most proteins by breaking down proteins that are old, damaged, or no longer needed. They also perform the highly regulated removal of specific proteins that signal to important and diverse events such as cell division, stress responses and chromatin maintenance. Despite 30 years of research, many of the fundamental aspects of proteasome function are still not fully characterised. We recently discovered an unexpected new level of proteasome regulation by divalent cations that challenges our current understanding of how the proteasome works. I want to build on our new data to unambiguously describe how proteasomes work inside the cells. For this I will use electron microscopy based structural analysis, together with biochemical and biophysical methods, to visualise in detail how they are regulated by divalent cations and how they recognise and process the proteins to be degraded. Because the proteasome is a critical cell regulator, understanding its fundamental working mechanisms will have a broad impact in biological sciences in general. The outputs of the proposed work have the potential of contributing to the clarification of critical mechanisms underlying conditions such as cancer progression, neurodegeneration, and aging, where proteasome dysfunction and calcium deregulation have been implicated, with impact for a wide range of beneficiaries. The proteasome is a well-established drug target for conditions including cancer, so in addition to improving basic knowledge the proposal has the potential to contribute to further developments in drug discovery and development.