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)和2022年(Rahman等人，分子生物学杂志，2022年)。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)。我们现在计划直接测量IFITM3对膜刚性的影响，这一功能与其抑制病毒进入的能力有关。此外，我们计划评估两亲性螺旋在IFITM3的致癌功能中所起的功能作用，包括它作为质膜上PI3K信号支架的能力。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) and one article in 2022 (Rahman et al., Journal of Molecular Biology, 2022). 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 directly measure cholesterol binding by IFITM3 contributes to its effect on membrane rigidity, a feature that is functionally tied to its capacity to inhibit virus entry. Furthermore, we plan to assess the functional role played by the amphipathic helix in the oncogenic functions of IFITM3, including its ability to act as a scaffold for PI3K signaling at 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.