Targeted Fungal RAS Signaling for Antimicrobial Therapy

摘要：项目2 -靶向真菌Ras信号转导用于抗菌治疗 重要Ras信号转导途径的蛋白质作为靶点已经被深入研究， 抗癌治疗，而且在其他疾病中也有潜力。我们已经发现Ras的核心作用， Ras处理酶在真菌致病中的作用，特别是与病原菌的高降解能力有关。 温度增长我们的证据表明，Ras通路的抑制剂可以作为新的治疗方法 来治疗人类真菌疾病许多化合物处于临床前开发和临床试验中， 抑制Ras，我们建议从这些已知的抑制剂开始设计具有改善的抗真菌活性的药物 基于我们对蛋白质结构的了解。 我们的目标是修饰Ras蛋白质的异戊烯基转移酶，我们还将探索一种新的方法。 第二组Ras修饰酶，棕榈酰转移酶。这两种蛋白质都是 Ras信号蛋白的正确定位;没有酶的活性，Ras功能丧失。我们有 研究了哺乳动物异戊烯基转移酶的结构，并帮助开发了专门的异戊烯基转移酶 抑制剂的在最近的工作中，我们还解决了四种真菌异戊烯基转移酶的结构， 和GGT酶。我们的工作揭示了在细胞中保守的分子特征， 真菌的酶，但不同于哺乳动物的酶。这种真菌特有的特征表明， 抑制剂可以衍生化以增强抗真菌作用。我们的数据还表明，Ras抑制将 与针对真菌钙调磷酸酶和海藻糖途径的疗法协同（项目1和3）。 在这项提案中，我们建立和扩大我们的结构为基础的研究，以开发新的协同，广泛的， 广谱抗真菌药我们提出了三个具体目标：1）重定向大量的FTase抑制剂 使用结构指导的方法，将癌症化疗药物开发的FTIs（FTIs）转化为抗真菌药物。2)到 研究GGT酶作为抗真菌药物靶点，并使用结构指导类似地开发有效抑制剂 接近。3)研究Ras家族蛋白棕榈酰化在真菌致病中的作用， 治疗靶向的潜力。棕榈酰转移酶在真菌和哺乳动物之间高度不同， 我们提出的遗传和生物化学研究将允许集中筛选和优化 棕榈酰化抑制剂作为新的抗真菌剂。该项目将利用所有三个核心，并与 本计划项目的项目1和项目2旨在加速开发治疗生命的新型药物- 威胁人类的真菌感染。

ABSTRACT: Project 2 – Targeted Fungal Ras Signaling for Antimicrobial Therapy Proteins of the important Ras signal transduction pathway have been intensely studied as targets for anticancer therapeutics, but also hold potential in other diseases. We have found central roles for Ras and Ras-processing enzymes in fungal pathogenesis, particularly related to pathogens' capability for high temperature growth. Our evidence suggests that inhibitors of the Ras pathway could serve as novel therapies to treat human fungal diseases. Numerous compounds are in preclinical development and in clinical trials that inhibit Ras, and we propose to start from these known inhibitors to design agents with improved antifungal properties based on our knowledge of the proteins' structures. Our targets are enzymes called prenyltransferases that modify Ras proteins, and we also will explore a second set of Ras-modifying enzymes, the palmitoyltransferases. Both of these proteins are required for proper localization of Ras signaling proteins; without the enzymes' activities, Ras function is lost. We have studied the structure of mammalian prenyltransferases and have helped develop focused prenyltransferase inhibitors. In more recent work, we also have solved the structures of four fungal prenyltransferases, FTase and GGTase, in different pathogenic fungi. Our work has revealed molecular features that are conserved in the fungal enzymes but differ from the mammalian ones. Such fungal-specific features suggest that current inhibitors could be derivatized for enhanced antifungal effect. Our data also indicate that Ras inhibition will be synergistic with therapies directed against fungal calcineurin and trehalose pathways (Projects 1 and 3). In this proposal, we build on and expand our structure-based studies to develop novel synergistic, broad- spectrum antifungals. We propose three Specific Aims: 1) To redirect the large collections of FTase inhibitors (FTIs) developed for cancer chemotherapeutics to antifungal agents using structure-guided approaches. 2) To investigate GGTase as an antifungal drug target, and similarly develop potent inhibitors using structure-guided approaches. 3) To investigate palmitoylation of Ras-family proteins in fungal pathogenesis, and evaluate its potential for therapeutic targeting. Palmitoyltransferases are highly divergent between fungi and mammals, and our proposed genetic and biochemical studies will allow the focused screening and optimization of palmitoylation inhibitors as new antifungals. This Project will utilize all three Cores and interact closely with Projects 1 and 2 of this Program Project in order to accelerate development of novel agents to treat life- threatening fungal infections in humans.