Function and regulation of the Cdc48-20S proteasome

Cdc48-20S蛋白酶体的功能和调节

• 批准号: 234232818
• 负责人: Dr. Dominik Barthelme
• 金额: --
• 依托单位: Max-Planck-Institut für Infektionsbiologie
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/234232818?language=en
• 关键词: Function; regulation; Cdc48; 20S; proteasome

Proteasomes, the major ATP-dependent proteases in the eukaryotic and archaeal domains of life, are required for degradation of damaged or misfolded proteins during protein-quality control and for regulation of diverse cell-signalling pathways. To execute protein degradation, the 20S peptidase combines with the hexameric AAA+ enzymes of the 19S regulatory particle in eukarya or with the AAA+ ring of archaeal PAN.In pilot studies, I identified the Cdc48-20S complex as a novel proteasome in the archaeon Thermoplasma acidophilum. Cdc48 (alias p97/VCP/VAT) is an abundant and essential double-ring AAA+ molecular machine ubiquitously present in archaea and eukarya. The physiological role of archaeal Cdc48 has long been uncertain, but eukaryotic Cdc48 participates by largely unknown mechanism in a myriad of biological processes, including membrane fusion, cell-cycle regulation, and the ubiquitin-proteasome-system. Intriguingly, the sequence and structural features that allow archaeal Cdc48 and 20S to collaborate in protein degradation are also conserved in the eukaryotic enzymes. Proteolysis in collaboration with the 20S peptidase may therefore be an ancestral function of the Cdc48 family that has have been preserved over billions of years of evolution.Key questions about the modus operandi, physiological function, and cellular regulation of this novel proteasome remain to be answered. Solving a high-resolution cryo-EM structure of the archaeal Cdc48-20S proteasome will help understanding how both macromolecules interact. I will also explore how adapter proteins interact with Cdc48, affect its conformation, and allosterically regulate its function using biochemical interaction studies, mechanistic enzymology, and biophysical characterization. Finally, I will test the exciting possibility that an alternative Cdc48-20S proteasome also functions in the eukaryotic domain of life.I aim to understand how native and misfolded proteins are recognized, unfolded, translocated, and finally degraded by Cdc48-20S proteasome. My research will answer questions about the evolutionary origins of proteasomes and will provide insights into the operational principles of this ATP-dependent protease and related enzymes. My work will also help to clarify the role of eukaryotic Cdc48 during ubiquitin-dependent proteolysis, cell cycle regulation, and protein-misfolding diseases.

蛋白酶体是真核生物和古细菌中主要的ATP依赖性蛋白酶，在蛋白质质量控制过程中降解受损或错误折叠的蛋白质以及调节不同的细胞信号传导途径是必需的。为了执行蛋白质降解，20 S肽酶与真核生物中19 S调节颗粒的六聚体AAA+酶或古菌PAN的AAA+环相结合。在初步研究中，我确定Cdc 48 - 20 S复合物是古菌嗜酸热浆菌中的一种新型蛋白酶体。Cdc 48（别名p97/VCP/VAT）是一个丰富的和必需的双环AAA+分子机器，广泛存在于古细菌和真核生物中。古细菌Cdc 48的生理作用长期以来一直不确定，但真核生物Cdc 48参与了大量的生物过程，包括膜融合，细胞周期调控，和泛素-蛋白酶体系统在很大程度上未知的机制。有趣的是，允许古细菌Cdc 48和20 S在蛋白质降解中协作的序列和结构特征在真核酶中也是保守的。因此，与20 S肽酶合作的蛋白水解可能是Cdc 48家族的祖先功能，该家族在数十亿年的进化过程中一直保留着，关于这种新型蛋白酶体的工作方式、生理功能和细胞调控的关键问题仍有待回答。解决古细菌Cdc 48 - 20 S蛋白酶体的高分辨率cryo-EM结构将有助于理解两种大分子如何相互作用。我还将探讨衔接蛋白如何与Cdc 48相互作用，影响其构象，并使用生化相互作用研究，机械酶学和生物物理特性变构调节其功能。最后，我将测试一个令人兴奋的可能性，一个替代Cdc 48 - 20 S蛋白酶体也在真核生物领域的功能。我的目标是了解如何天然和错误折叠的蛋白质被识别，解折叠，易位，并最终由Cdc 48 - 20 S蛋白酶体降解。我的研究将回答有关蛋白酶体的进化起源的问题，并将提供这种ATP依赖性蛋白酶和相关酶的操作原理的见解。我的工作也将有助于阐明真核Cdc 48在泛素依赖性蛋白水解、细胞周期调控和蛋白质错误折叠疾病中的作用。