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

描述（由申请人提供）：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直接传播给人类的持续事件、H1N1人类毒株中对当前抗流感药物的耐药毒株的高流行率以及猪源H1N1和高致病性禽H5 N1毒株之间的高遗传相容性表明，人类面临致命的耐药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合理的新策略是靶向病毒所需的细胞成分。在我们以前的研究中，我们评估了细胞SUMO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作为真正的SUMO靶标，揭示了病毒触发细胞SUMO化的两倍全球增加的能力，并证明细胞SUMO化的大的全球变化影响病毒蛋白表达和病毒增殖。因此，细胞SUMO化系统似乎在流感病毒感染中起重要作用。重要的是，在鉴定的所有病毒SUMO靶点中，非结构蛋白NS 1是SUMO化最有效的。考虑到这一事实，NS 1在病毒感染过程中发挥的众多作用，以及通常与SUMO化相关的功能，我们假设SUMO化通过影响NS 1与其他病毒和细胞蛋白建立特异性蛋白质-蛋白质相互作用的能力来调节NS 1功能，从而解释了其与流感感染的相关性。为了验证这一假设，我们将评估NS 1 SUMO化对两个主要参数的影响：i）NS 1与其他病毒和细胞蛋白相互作用的能力。ii）NS 1的主要功能和生物化学特征，即其中和I型干扰素应答的能力、其细胞定位和其半衰期。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NS 1 SUMO化的人工调节剂的组合进行。所产生的数据将为流感病毒感染期间NS 1功能的翻译后调节和SUMO化介导的分子效应提供重要见解，并可能导致鉴定用于开发广谱抗流感疗法的新靶点。此外，这些研究还将扩大我们对病毒和细胞SUMO化系统之间建立的相互作用的理解。 公共卫生相关性：流感仍然是造成年度流行病的主要传染病，能够造成极具破坏性的大流行病。更好地了解病毒与其宿主细胞之间建立的多种相互作用可能会导致开发更有效的治疗方法。本研究将在分子水平上表征宿主翻译后修饰系统对非结构蛋白NS 1的影响，可能导致新的抗病毒靶点的鉴定。

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. PUBLIC HEALTH RELEVANCE: Influenza remains a major infectious disease responsible for annual epidemics and capable of producing extremely damaging pandemics. A better knowledge of the multiple interactions established between the virus and its host cell will likely lead the way to the development of more effective treatments. This study will characterize at the molecular level the effects exerted by a host's post-translational modification system upon the non-structural protein NS1, potentially leading to the identification of novel antiviral targets.