Targeted Fungal RAS Signaling for Antimicrobial Therapy

摘要：项目2-针对真菌RAS信号的抗菌治疗 重要的RAS信号转导途径的蛋白质已被广泛研究为靶点 抗癌疗法，但也具有治疗其他疾病的潜力。我们已经找到了RAS和 RAS处理酶在真菌发病机制中的作用，特别是与病原菌对高致病性的 温度增长。我们的证据表明，RAS途径的抑制剂可以作为新的治疗方法 治疗人类真菌病。许多化合物正在进行临床前开发和临床试验 抑制RAS，我们建议从这些已知的抑制剂开始设计具有改进的抗真菌药物 基于我们对蛋白质结构的了解而产生的特性。 我们的目标是修饰RAS蛋白的称为异丙苯基转移酶的酶，我们还将探索一种 第二组RAS修饰酶，棕榈酰基转移酶。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功能就会丧失。我们有 研究哺乳动物异丙烯基转移酶的结构，并帮助开发有针对性的异丙烯基转移酶 抑制剂。在最近的工作中，我们还解决了四种真菌戊烯基转移酶，FTase的结构 和GGTase，在不同的病原真菌中。我们的工作揭示了在细胞内保守的分子特征 真菌酶，但不同于哺乳动物的酶。这种真菌特有的特征表明，目前 为了增强抗真菌作用，可以对抑制剂进行衍生化。我们的数据还表明，RAS的抑制将是 与针对真菌钙调神经磷酸酶和海藻糖途径的治疗协同作用(项目1和3)。 在这项建议中，我们建立和扩大我们的基于结构的研究，以开发新的协同作用，广泛的 光谱抗真菌药。我们提出了三个具体目标：1)重定向FTase抑制剂的大量集合 (FTIs)开发用于癌症化疗药物和使用结构引导方法的抗真菌药物。2)至 研究GGTase作为抗真菌药物的靶点，并利用结构导向类似地开发有效的抑制剂 接近了。3)探讨ras家族蛋白的棕榈酰化在真菌发病中的作用。 潜在的治疗靶向。棕榈酰基转移酶在真菌和哺乳动物之间差异很大，而且 我们建议的遗传和生化研究将允许重点筛选和优化 棕榈酰化抑制剂作为新的抗真菌药物。该项目将利用所有三个核心，并与 本计划项目1和2，以加快开发治疗生命的新型药物-- 威胁着人类的真菌感染。

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.