Role of host protein GBF1 in organizing enterovirus replication complexes

项目描述。病毒是终极的细胞内寄生虫。以最低限度的遗传 他们能够改变细胞代谢途径并劫持细胞蛋白质以促进 它们自己的复制。因此，了解特定宿主因子在病毒生命周期中的作用是至关重要的。 用于开发新的抗病毒策略。肠道病毒是一组小核糖核酸病毒，小 包括人类在内的脊椎动物的+RNA病毒。肠道病毒在临床上和经济上引起 重要的人类疾病，从普通感冒到致命的脑炎和心肌炎。高 这些病毒的遗传多样性和适应性使综合疫苗的开发变得复杂 以及针对病毒特异性蛋白的传统疗法。在所有致病的肠道病毒中，只有 脊髓灰质炎病毒可以通过疫苗控制，没有临床批准的抗肠病毒药物可以 可用。因此，迫切需要新的方法来控制与人类相关的肠道病毒。 疾病。微小核糖核酸病毒在特殊的膜域上复制它们的基因组 细胞器以独特的脂肪和蛋白质组成为特征，其发育依赖于细胞的再生长。 细胞脂质合成和膜运输途径的组织。这意味着至少有一些 细胞膜代谢成分对于病毒的繁殖是必不可少的。的确， 肠道病毒的复制普遍需要宿主蛋白GBF1。GBF1是一个大型的多域 作为精氨酸脱氢酶小分子GTP酶的鸟嘌呤核苷酸交换因子的蛋白质 一家人。GBF1是分泌途径中蛋白质运输早期步骤的主协调者，并且 参与维持高尔基体的结构和功能，并参与脂滴代谢。然而，如何 GBF1支持的病毒复制周期尚不清楚。试图将已知的细胞 GBF1的活性，如Arf激活、膜重塑和细胞蛋白募集到 膜对GBF1在病毒复制中的作用产生了争议的结果。已知GBF1可以相互作用 大量的细胞蛋白和肠道病毒复制蛋白3A，但病毒如何利用这些 对他们有利的互动仍不得而知。在这里，我们提出了一种新的模型，在其中GBF1起作用 作为分子支架，协调病毒和细胞蛋白的组装，形成可操作的复制 复合体。为了这个项目，我们建立了一支在GBF1生物学方面拥有卓越专业知识的细胞生物学家团队 (Sztul)，以及一位在小核糖核酸病毒复制方面具有杰出背景的病毒学家(Belov)。在一起，我们 我将描绘病毒生命周期中需要GBF1的步骤(S)，并揭示GBF1的作用机制 在复制复合体的形成功能中。各种肠道病毒普遍依赖于 GBF1为广谱疗法的发展提供了前所未有的机遇 靶向受感染细胞中受GBF1控制的过程。

Description of the project. Viruses are the ultimate intracellular parasites. With minimal genetic resources they are able to reroute cellular metabolic pathways and hijack cellular proteins to promote their own replication. Thus, understanding the role of specific host factors in the viral life cycle is essential for the development of novel anti-viral strategies. Enteroviruses are a group of picornaviruses, small +RNA viruses of vertebrates including humans. Enteroviruses cause clinically and economically important human diseases, ranging from the common cold to fatal encephalitis and myocarditis. High genetic diversity and adaptability of these viruses complicates development of comprehensive vaccines and traditional therapeutics targeting virus-specific proteins. Of all the pathogenic enteroviruses, only polioviruses can be controlled with vaccines, and no clinically approved anti-enterovirus drugs are available. Thus, novel approaches are urgently needed to control enteroviruses associated with human diseases. Picornaviruses replicate their genomes on specialized membrane domains, replication organelles that feature unique lipid and protein composition and whose development relies on the re- organization of cellular lipid synthesis and membrane trafficking pathways. This implies that at least some cellular membrane metabolism components must be indispensable for viral propagation. Indeed, enteroviruses universally require the host protein GBF1 for their replication. GBF1 is a large multi-domain protein that functions as a guanine nucleotide exchange factor (GEF) for select small GTPases of the Arf family. GBF1 is a master coordinator of the early steps of protein transport in the secretory pathway, and participates in maintaining Golgi structure and function and in lipid droplet metabolism. However, how GBF1 supports the viral replication cycle remains unknown. Attempts to relate the known cellular activities of GBF1 such as Arf activation, membrane remodeling and recruitment of cellular proteins to membranes to GBF1 function in viral replication produced controversial results. GBF1 is known to interact with numerous cellular proteins and with the enterovirus replication protein 3A, but how viruses use these interactions to their advantage remains unknown. Herein, we propose a new model in which GBF1 acts as a molecular scaffold to coordinate the assembly of viral and cellular proteins into operational replication complexes. For this project, we built a team of a cell biologist with a superior expertise in GBF1 biology (Sztul), and a virologist with an outstanding background in picornavirus replication (Belov). Together, we will delineate the step(s) in viral life cycle that require GBF1 and uncover the mechanisms of GBF1 action in the formation function of replication complexes. The universal reliance of diverse enteroviruses on GBF1 provides an unprecedented opportunity for the development of broad-spectrum therapeutics targeting GBF1-controlled processes in infected cells.