Molecular effects of SUMOylation on influenza virus infection: SUMO and NS1

描述(申请人提供)：流感病毒仍然是全球人类健康的主要威胁。高致病性禽流感毒株持续直接传播给人类，H1N1人类毒株对当前抗流感药物的抗药性高，以及猪源H1N1和高致病性禽流感H5N1毒株之间的高度遗传兼容性，表明人类面临致命抗药性大流行毒株出现的可能性仍然很高。开发广谱抗流感疗法的一个看似合理的新策略是针对病毒所需的细胞成分。在我们之前的研究中，我们评估了细胞糖基化系统与流感感染的相关性。我们的数据确定了几种流感蛋白是真正的相扑目标，揭示了该病毒触发细胞SUMO化的全球增加两倍的能力，并表明细胞SUMO化的大的全球变化影响病毒蛋白的表达和病毒的复制。因此，细胞糖基化系统在流感病毒感染中起着重要的作用。重要的是，在所有已确定的病毒相扑靶标中，非结构蛋白NS1的SUMO化效率最高。考虑到NS1在病毒感染过程中扮演的众多角色，以及通常与SUMO化相关的功能，我们假设SUMO化通过影响NS1与其他病毒和细胞蛋白建立特定蛋白质-蛋白质相互作用的能力来调节NS1的功能，从而解释其与流感感染的相关性。为了验证这一假说，我们将评估NS1 SUMO化对两个主要参数的影响：i)NS1‘S与其他病毒和细胞蛋白相互作用的能力。Ii)NS1的主要功能和生化特征，即其中和I型干扰素反应的能力、其细胞定位和半衰期。这些研究将使用蛋白质突变体、病毒突变体、稳定转导的细胞系和人工调节NS1 SUMO化的组合来进行。这些数据将为流感病毒感染过程中NS1功能的翻译后调控和SUMO化所介导的分子效应提供关键的见解，并可能导致为开发广谱抗流感疗法而识别新的靶点。此外，这些研究还将扩大我们对病毒和细胞SUMO化系统之间相互作用的理解。

DESCRIPTION (provided by applicant): Influenza virus continues to be a major threat to global human health. The persistent episodes of direct transmission of highly pathogenic avian influenza strains to humans, the high prevalence of resistant strains to current anti-influenza drugs among H1N1 human strains, and the high genetic compatibility between swine- origin H1N1 and highly pathogenic avian H5N1 strains, suggest that the odds of humanity facing the emergence of a deadly drug-resistant pandemic strain remain high. A plausible new strategy to develop broad- spectrum anti-influenza therapies is to target cellular components required by the virus. In our previous studies, we evaluated the relevance of the cellular SUMOylation system for influenza infection. Our data identified several influenza proteins as bona fide SUMO targets, revealed the ability of the virus to trigger a two-fold global increase in cellular SUMOylation, and demonstrated that large global changes in cellular SUMOylation affect viral protein expression and virus multiplication. Therefore, the cellular SUMOylation system appears to play an important role for influenza virus infections. Importantly, out of all viral SUMO targets identified, the non-structural protein NS1 was the most efficiently SUMOylated. Considering this fact, the numerous roles played by NS1 during viral infection, and the functions normally associated to SUMOylation, we hypothesize that SUMOylation regulates NS1 function by affecting its ability to establish specific protein-protein interactions with other viral and cellular proteins, thus explaining its relevance for influenza infection. To test this hypothesis, we will evaluate the effects exerted by NS1 SUMOylation on two main parameters: i) NS1's ability to interact with other viral and cellular proteins. ii) The main functional and biochemical characteristics of NS1, namely its ability to neutralize type-I interferon responses, its cellular localization, and its half-life. These studies will be pursued using a combination of protein mutants, viral mutants, stably transduced cell lines, and an artificial modulator of NS1 SUMOylation. The data generated will provide critical insights on the post- translational regulation of NS1 function and the molecular effects mediated by SUMOylation during influenza virus infection, and potentially lead to the identification of novel targets for the development of broad-spectrum anti-influenza therapies. Additionally, these studies will also expand our understanding of the interactions established between viruses and the cellular SUMOylation system.