Characterization of Parp14-Trim25 directed mitochondrial ISGylation and its antagonism by viral deISGylases

Parp14-Trim25 定向线粒体 ISG 化的表征及其病毒去 ISG 酶的拮抗作用

• 批准号: BB/Y000307/1
• 负责人: Sumana Sanyal
• 金额: $ 63.34万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FY000307%2F1
• 关键词: Characterization; Parp14; Trim25; directed; mitochondrial

Interferon stimulated gene 15 (ISG15) is a ubiquitin like post-translational modifier, and expressed in abundance upon immune challenges such as infection, and other cellular stresses such as mitochondrial disruption, ageing and DNA damage. ISG15 can modify substrates in a process referred to as ISGylation. Many viruses in turn have co-evolved the ability to hydrolyse ISG15 modifications via the reverse reaction referred to as deISGylation, allowing them to subvert host cell function and innate immune responses.Much of the innate immune signalling takes place at the mitochondrial membranes, which function as platforms or signalling hubs in collaboration with the endoplasmic reticulum membrane. These processes consist of various signalling branches with specificity for different pathogen classes. The role of ISGylation in antiviral signalling at the mitochondria and subsequent virus restriction are poorly understood processes.Our efforts to expand the knowledge on the role of ISGylation, recently led to the identification of a new antiviral branch defined by the Poly ADP-ribosyltransferase 14 (Parp14) enzyme together with an E3 ligase Trim25. We showed that this enzyme drives ISGylation of as yet unidentified substrates at the mitochondria. Many of these substrates in turn are deISGylated by a viral protease (SARS-CoV-2 PLpro). How Parp14-Trim25 functions to regulate ISGylation at the mitochondria, and its functional implications are not known. Similarly, the full repertoire of substrates of Parp14-Trim25 and how its ADP-ribosyltransferase enzymatic activity impacts ISGylation remain important issues to address. While not much is known about Parp14-Trim25, deletion of Parp14 leads to increased susceptibility to virus infection and aberrant innate immune signalling. Importantly, viruses encoding potent deISGylating activities are also known to contain ADP-ribosylhydrolase activities in macrodomains and have effective immune suppression abilities. Whether these hydrolytic activities function in concert to evade host immunity is currently unknown.This proposal combines genetic, biochemical and proteomics approaches in cultured and hIPS-derived macrophages to systematically address these open questions. Our work will provide comprehensive insight into the novel Parp14-regulated antiviral branch and shed light on its physiological role in a relevant cellular system. The findings will inform on the mechanisms of antiviral immunity and other stress conditions, and those disrupted by many RNA viruses to ultimately offer hints toward novel avenues for therapeutic intervention.

干扰素刺激基因15（Interferon stimulated gene 15，ISG 15）是一种泛素样翻译后修饰物，在免疫挑战如感染和其他细胞应激如线粒体破坏、衰老和DNA损伤时大量表达。ISG 15可以在称为ISGylation的过程中修饰底物。许多病毒反过来又共同进化出了通过称为去ISGylation的逆反应水解ISG 15修饰的能力，使它们能够破坏宿主细胞功能和先天免疫应答。许多先天免疫信号传导发生在线粒体膜上，线粒体膜与内质网膜合作发挥平台或信号传导枢纽的作用。这些过程由对不同病原体类别具有特异性的各种信号传导分支组成。ISGylation在线粒体抗病毒信号传导和随后的病毒限制中的作用知之甚少。我们努力扩大对ISGylation作用的认识，最近发现了一个新的抗病毒分支，由聚ADP-核糖基转移酶14（Parp 14）和E3连接酶Trim 25共同定义。我们发现，这种酶驱动ISGylation的尚未确定的底物在线粒体。这些底物中的许多又被病毒蛋白酶（SARS-CoV-2 PLpro）去ISGylated。Parp 14-Trim 25如何发挥作用来调节线粒体的ISG化，及其功能意义尚不清楚。类似地，Parp 14-Trim 25的底物的全部库以及其ADP-核糖基转移酶酶促活性如何影响ISG化仍然是需要解决的重要问题。虽然对Parp 14-Trim 25的了解不多，但Parp 14的缺失导致对病毒感染和异常先天免疫信号的易感性增加。重要的是，还已知编码有效的去ISGylating活性的病毒在宏结构域中含有ADP-核糖基水解酶活性，并具有有效的免疫抑制能力。这些水解活性是否能协同逃避宿主免疫目前尚不清楚，该提案结合了培养的和HIPS-derived巨噬细胞的遗传学、生物化学和蛋白质组学方法，以系统地解决这些悬而未决的问题。我们的工作将提供全面的洞察到新的Parp 14调节的抗病毒分支，并阐明其在相关的细胞系统中的生理作用。这些发现将为抗病毒免疫和其他应激条件的机制以及被许多RNA病毒破坏的机制提供信息，最终为治疗干预的新途径提供线索。