Arrestin proteins mediate microbial cellular adaptation and fungal virulence

摘要 为了有效地引起疾病，微生物必须不断地感知并迅速作出反应。 不断变化的环境对于微生物病原体，这些适应性细胞过程包括响应 宿主产生的压力微生物调节这些适应性反应的鲁棒性在很大程度上 决定了它们在受感染宿主体内的生存能力。 在这个建议中概述的实验中，我们建立在我们实验室最近的和融合的数据之上。 支持蛋白质泛素化在微生物宿主反应中的重要性。最初定义为指导 蛋白质降解，泛素化越来越被认为是一种精确调节蛋白质降解的手段。 许多靶蛋白的定位和功能。在人类真菌病原体新型隐球菌中，我们 已经鉴定了Rsp 5泛素连接酶作为应激反应和毒力的关键介质。我们的初步 实验已经开始确定需要Rsp 5活性的致病过程的特定方面， 包括细胞壁稳态和细胞周期进程。与新出现的泛素化模型一致， 不同的物种，我们的实验结果表明，Rsp 5是针对其蛋白质靶点的衔接蛋白， 包括抑制蛋白家族。我们最初的体外和体内实验表明，毒力- 相关表型的C.新生儿rsp 5突变体可能是个体贡献的复合物， 改变靶蛋白功能。通过进一步定义微生物泛素连接酶/接头/靶蛋白轴，我们 将更深入地探索应激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.