Arrestin proteins mediate microbial cellular adaptation and fungal virulence

摘要 为了有效地导致疾病，微生物必须不断地感知并迅速做出反应 不断变化的环境。对于微生物病原体，这些适应性的细胞过程包括反应的能力 到主体衍生应力。微生物在很大程度上调节这些适应性反应的健壮性 确定它们在受感染的宿主内生存的能力。 在本提案中概述的实验中，我们以实验室的最新数据和汇聚数据为基础 支持蛋白质泛素化在微生物宿主反应中的重要性。最初定义为导演 对于蛋白质的降解，泛素化越来越被认为是一种精确调控 许多靶蛋白的定位和功能。在人类真菌病原体新生隐球菌中，我们 已经确定Rsp5泛素连接酶是应激反应和毒力的关键介体。我们的预赛 实验已经开始定义需要Rsp5活性的致病过程的具体方面， 包括细胞壁动态平衡和细胞周期进程。与泛素化的新兴模式相一致 不同物种，我们的实验结果表明，Rsp5通过接头蛋白定向到其蛋白质靶标， 包括arrestin蛋白家族。我们初步的体外和体内实验表明，毒力- 新生假单胞菌rsp5突变体的相关表型很可能是由 改变了靶蛋白功能。通过进一步定义微生物泛素连接酶/接头/靶蛋白轴，我们 将更深入地探索压力诱导的细胞反应影响真菌感染的机制。

Abstract In order to effectively cause disease, microorganisms must continuously sense and respond to rapidly changing environments. For microbial pathogens, these adaptive cellular processes include the ability to respond to host-derived stresses. The robustness with which microorganisms regulate these adaptive responses largely determines their ability to survive within the infected host. In the experiments outlined in this proposal, we build upon recent and converging data from our laboratory supporting the importance of protein ubiquitination in microbial host responses. Originally defined for directing proteins for degradation, ubiquitination is increasingly recognized as a means of precise regulation of the localization and function of many target proteins. In the human fungal pathogen Cryptococcus neoformans, we have identified the Rsp5 ubiquitin ligase as a key mediator of stress response and virulence. Our preliminary experiments have begun to define the specific aspects of the pathogenic process that require Rsp5 activity, including cell wall homeostasis and cell cycle progression. Consistent with emerging models of ubiquitination in diverse species, our experimental results suggest that Rsp5 is directed to its protein targets by adaptor proteins, including the arrestin protein family. Our initial in vitro and in vivo experiments indicate that the virulence- associated phenotypes of the C. neoformans rsp5 mutant are likely a composite of individual contribution of altered target protein function. By further defining the microbial ubiquitin ligase / adaptor / target protein axis, we will more deeply explore the mechanisms by which stress-induced cellular responses influence fungal infections.