Modular Domains of Host Proteins Regulate Filovirus Maturation

这一建议的最终目的是阐明宿主BAG3的新的抗病毒机制；一种新的 发现了丝状病毒VP40相互作用蛋白，可抑制病毒出口。丝状病毒(埃博拉[EBOV]和 Marburg[Marv])是A类高优先级病原体，目前还没有商业用途 疫苗或治疗剂。因此，探索性和创新性的方法是有必要的，以更好地 了解促进和抑制这些致命病毒传播的病毒与宿主的相互作用。 我们的实验室专注于丝状病毒与宿主蛋白相互作用和招募宿主蛋白的机制。 调控萌芽过程。在这里，我们发现了丝状病毒VP40和丝状病毒VP40之间意外的相互作用 宿主蛋白BAG3。BAG3是一种受压力调节的辅助伴侣蛋白，其功能是确保细胞 通过伴侣辅助选择性自噬(CASA)的存活和蛋白质动态平衡。而BAG3则有 已被证明对某些病毒的进入和复制有积极影响，我们发现 EBOV和MARV VP40的PPxY基序与BAG3的单个N端WW结构域一起导致了 EBOV和MARV VP40病毒样颗粒(VLP)以及VSV的出口意外减少 作为功能性EBOV替代品的重组病毒，因为它们被基因工程改造成 表达EBOVVP40WT或突变的L结构域来代替VSVM的L结构域。我们假设 BAG3在丝状病毒感染后被诱导表达，并且BAG3靶向VP40进行移除 和/或从质膜上的萌发部位隔离。我们将用严谨的多面性 一种询问BAG3扰乱病毒颗粒出口的机制的方法，从而提供了新的 洞察CASA作为一种新的和特定的宿主防御策略的潜在作用 VP40，以促进病毒颗粒的有效扩散和扩散。

The ultimate goal of this proposal is to elucidate the novel antiviral mechanism of host BAG3; a newly discovered filovirus VP40 interacting protein that inhibits viral egress. Filoviruses (Ebola [EBOV] and Marburg [MARV]) are Category A, high-priority pathogens, for which there are no commercially available vaccines or therapeutic agents. Thus, exploratory and innovative approaches are warranted to better understand viral-host interactions that both promote and inhibit the transmission of these deadly viruses. Our laboratory focuses on the mechanisms by which filoviruses interact with and recruit host proteins to regulate the budding process. Here, we identified an unanticipated interaction between filovirus VP40 and the host protein BAG3. BAG3 is a stress-regulated, co-chaperone protein whose function is to ensure cell survival and protein homeostasis via Chaperone-Assisted Selective Autophagy (CASA). While BAG3 has been shown to positively influence entry and replication for some viruses, we found that the interaction of the PPxY motif of both EBOV and MARV VP40 with the single N-terminal WW-domain of BAG3 leads to an unexpected decrease in egress of both EBOV and MARV VP40 virus-like particles (VLPs), as well as VSV recombinant viruses that serve as functional EBOV surrogates, as they are genetically engineered to express either EBOV VP40 WT or mutant L-domains in place of the L-domain of VSV M. We hypothesize that BAG3 expression is induced following filovirus infection, and that BAG3 targets VP40 for removal and/or sequestration from the site of budding at the plasma membrane. We will use a rigorous multifaceted approach to interrogate the mechanisms by which BAG3 disrupts virus particle egress, thus providing new insight into the potential role of CASA as a novel and specific host defense strategy to counteract the ability of VP40 to promote efficient egress and spread of virus particles.