Mechanisms of Virus Entry into Cells and Antiviral Barriers Limiting Entry

我们在2020年发表了与该项目有关的两篇文章(Ahi等人，mBio，2020年；Rahman等人，eLife 2020年)，2022年发表了两篇文章(Rahman等人，《分子生物学杂志》，2022；Majdoul等人，《自然评论免疫学》，2022)，以及2023年到目前为止的一篇预印本(Shih等人，BioRxiv，2023)。我们的工作为IFITM蛋白及其所属的扩展CD225蛋白家族的功能提供了广泛的见解，并将为新的抗病毒疗法的开发提供杠杆作用。值得注意的是，我们发现了IFITM3对多种病毒的抗病毒活性所需的两亲性α螺旋，包括HIV-1、寨卡病毒和甲型流感病毒(Chesarino，Compton等人)。EMBO报告，2017)。随后，我们表明两亲性螺旋是IFITM3改变细胞膜生物物理属性(膜硬度和曲率)的能力所必需的(Rahman等人，eLife，2020)。最近，我们证明了两亲性螺旋显示了直接的胆固醇结合活性，为它对膜的影响提供了可能的解释，并为IFITM3如何限制膜融合孔的形成提供了一个可信的机制(Rahman等人，《分子生物学杂志》，2022)。我们现在计划通过使用分子动力学模拟将胆固醇结合到计算机分析中，来研究IFITM3与胆固醇结合是如何直接影响其抗病毒活性的。我们还将评估IFITM3与脂质结合如何影响其在细胞和蛋白质半衰期内的运输。此外，我们的发现将使我们更好地了解IFITM3和相关蛋白所扮演的细胞角色，包括它作为质膜脂筏上受体酪氨酸受体信号转导的支架的能力。我们的发现将为深入了解该蛋白家族所扮演的不良致癌作用，并为灭活提供治疗靶点。

We published two articles pertaining to this project in 2020 (Ahi et al., mBio, 2020; Rahman et al., eLife 2020), two articles in 2022 (Rahman et al., Journal of Molecular Biology, 2022; Majdoul et al., Nature Reviews Immunology, 2022), and one preprint so far in 2023 (Shi et al., bioRxiv, 2023). Our work provides extensive insight into the function of IFITM proteins as well as the extended CD225 protein family to which they belong and will provide leverage for the development of new antiviral therapies. Notably, we identified an amphipathic alpha helix that is required for the antiviral activity of IFITM3 against multiple viruses, including HIV-1, Zika virus, and Influenza A virus (Chesarino, Compton et al. EMBO Reports, 2017). Subsequently, we showed that the amphipathic helix is required for the ability of IFITM3 to alter the biophysical properties of cellular membranes (membrane rigidity and curvature) (Rahman et al., eLife, 2020). Most recently, we demonstrated that the amphipathic helix exhibits direct cholesterol binding activity, providing a possible explanation for its impacts on membranes and a plausible mechanism for how IFITM3 restricts membrane fusion pore formation (Rahman et al., Journal of Molecular Biology, 2022). We now plan to examine how cholesterol binding by IFITM3 directly contributes to its antiviral activities by incorporating in silico analyses using molecular dynamics simulations. We will also assess how lipid binding by IFITM3 affects its trafficking through the cell and protein half-life. In addition, our findings will allow us to better understand the cellular roles played by IFITM3 and related proteins, including its ability to act as a scaffold for receptor tyrosine receptor signaling at lipid rafts in the plasma membrane. Our findings will provide insight into the poorly characterized tumorigenic roles played by this family of proteins and provide therapeutic targets for inactivation.