Mammalian 20S proteasome isotypes: from structure and function to selective inhibition

哺乳动物 20S 蛋白酶体同种型：从结构和功能到选择性抑制

• 批准号: 256398100
• 负责人: Professor Dr. Michael Groll
• 金额: --
• 依托单位: Lehrstuhl für Biochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/256398100?language=en
• 关键词: Mammalian; 20S; proteasome; isotypes; structure

The 20S proteasome core particle (CP) is the key player of the non-lysosomal protein degradation pathway, controls a plethora of essential intracellular processes and is a validated drug target. While simple eukaryotes express only one type of CP, the evolution of mammals and their increased complexity led to diversification and differentiation of the CP, ultimately resulting in four isotypes. Present in all cells, the constitutive proteasome (cCP) accomplishes the bulk of polypeptide degradation required for protein homoeostasis and survival. In contrast, the immunoproteasome (iCP) and the thymoproteasome (tCP) are engaged in shaping a functional adaptive immune system, whereas the role of the spermatoproteasome (sCP) is yet to be elucidated. Although the overall architecture of CP isotypes is identical, their subunit composition varies. Inhibitors that do not discriminate between CP isotypes are blockbuster drugs for the treatment of blood cancers and additional medicinal applications of iCP-selective compounds, e.g. chronic inflammatory or autoimmune diseases, are explored in clinical trials. During the current funding period extensive structure-based inhibitor and mutagenesis studies were performed on cCP and iCP, the results of which we have reported in 11 publications. To date, both tCP and sCP are poorly understood and their structural examination would provide a more thorough understanding of the unique subunits ß5t and Alpha 4s, respectively. Therefore, in the applied follow-up project we aim to structurally and biochemically characterize the tCP. In particular, the analysis of cleavage patterns of tCP versus cCP and iCP will be used to develop tCP-specific ligands. Such compounds may serve future efforts to probe the biological function of the tCP and any medicinal relevance of its selective inactivation. Similar to our work on the iCP, yeast mutagenesis efforts are envisioned to determine crucial elements of ß5t for assembly and function of the tCP. Besides, elaborate experiments on the sCP are planned. The primary goal is expression, purification and crystallization of the genuine human sCP or of a chimeric CP, i.e. a yeast CP that contains the human sCP-specific α4s entity. The envisioned interdisciplinary concept of this proposal certainly will enrich basic proteasome research and may open up future directions in CP drug development. The excellent infrastructure and the long lasting expertise of my lab allow to expect also promising new insights into 20S proteasome isotypes.

20S蛋白酶体核心颗粒(CP)是非溶酶体蛋白降解途径的关键分子，控制着大量的细胞内过程，是一个有效的药物靶点。虽然简单的真核生物只表达一种类型的CP，但哺乳动物的进化及其复杂性的增加导致了CP的多样化和分化，最终形成了四种同功型。构成蛋白酶体(CCP)存在于所有细胞中，完成蛋白质稳态和生存所需的大部分多肽降解。相比之下，免疫蛋白酶体和胸腺蛋白酶体参与了功能性适应性免疫系统的形成，而精子蛋白酶体(SCP)的作用尚不清楚。虽然CP亚型的整体结构是相同的，但它们的亚基组成不同。不区分CP同种类型的抑制剂是治疗血癌的重磅炸弹药物，临床试验中还探索了ICP选择性化合物的其他医学应用，例如慢性炎症或自身免疫性疾病。在本供资期间，对CCP和ICP进行了广泛的基于结构的抑制物和诱变研究，我们已在11份出版物中报告了其结果。到目前为止，对TCP和SCP的了解都很少，它们的结构研究将提供更全面的了解，分别是独特的亚基？5t和Alpha 4s。因此，在应用后续项目中，我们的目标是对TCP的结构和生化特性进行表征。特别是，将利用对TCP与CCP和ICP的切割模式的分析来开发TCP特定的配体。这些化合物可能有助于未来探索磷酸三氢叶酸的生物学功能以及其选择性失活的任何药用价值。与我们在ICP上的工作类似，酵母菌的诱变努力是为了确定tcp组装和功能所需的5t的关键元素。此外，还计划对SCP进行详细的实验。主要目标是表达、纯化和结晶真正的人SCP或嵌合CP，即包含人SCP特异性α4S实体的酵母CP。这一方案设想的跨学科概念肯定会丰富蛋白酶体的基础研究，并可能开辟未来CP药物开发的方向。我的实验室优良的基础设施和持久的专业知识也让我们有希望对20多岁的蛋白酶体亚型有新的见解。