Paramyxovirus F protein mediated membrane fusion

 描述（由申请人提供）：过去十年中令人信服的工作表明，曾经被认为仅作为疏水锚发挥作用的跨膜结构域（TMD）是驱动细胞蛋白质寡聚化、细胞信号传导和通道调节的核心参与者。 功能然而，TMDs在病毒糖蛋白稳定性和功能中的作用仍然知之甚少。在之前的资助期间，我们对亨德拉病毒（HeV）融合（F）蛋白的研究确定了TMD在调节F蛋白稳定性、细胞运输和融合功能方面的关键作用。我们的新研究利用沉降平衡（SE）分析建立了F蛋白TMD有效地三聚体分离的其余蛋白质。改变TM-TM协会被发现多个功能上重要的突变，涉及TM-TM相互作用的调节F蛋白折叠和功能。我们研究的长期目标是 了解副粘病毒F蛋白促进膜融合的分子细节和调控。该建议的总体假设是TMD与其自身和脂质环境的相互作用对于融合蛋白的稳定性和功能是至关重要的，使得这些相互作用成为抗病毒治疗的潜在靶标。为了验证这一重要假设， 我们会致力达致三个目标。首先，我们将定义驱动F蛋白TM-TM相互作用的关键要素，包括定义L/I七肽在TM-TM缔合和Hendra F蛋白稳定性中的作用。其次，我们将确定TMD如何影响融合触发和促进膜融合，重点是C-末端的α-分支残基的作用，并确定当TM-TM相互作用不能释放时可能发生的构象变化。第三，我们将剖析的作用，脂质环境中的融合前F稳定性的背景下，细胞和病毒膜。这些重要的实验将提供关键的新的见解，在F蛋白的稳定性和融合促进的调节中的作用TMDs。

 DESCRIPTION (provided by applicant): Compelling work in the last decade has shown that transmembrane domains (TMDs), once thought to function solely as hydrophobic anchors, are central players driving cellular protein oligomerization, cell signaling, and regulation of channel function. However, the role of TMDs in viral glycoprotein stability and function remains poorly understood. During the previous funding period, our studies of the Hendra virus (HeV) fusion (F) protein identified key roles for TMDs in regulation of F protein stability, cellular trafficking, ad fusion function. Our novel studies utilizing sedimentation equilibrium (SE) analysis established that F protein TMDs efficiently trimerize separate from the rest of the protein. Altered TM-TM association was found for multiple functionally important mutations, implicating TM-TM interactions in regulation of F protein folding and function. The long-term goal of our research is to understand the molecular details and regulation of membrane fusion promoted by the paramyxovirus F proteins. The overall hypothesis of this proposal is that interactions of the TMD with itself and the lipid environment are critical for fusion protein stability and function, makin these interactions potential targets for antiviral therapeutics. To test this important hypothesis, we will pursue three specific aims. First, we will define key elements driving F protein TM-TM interactions including defining the role of a L/I heptad in TM-TM association and Hendra F protein stability. Second, we will determine how the TMD affects fusion triggering and promotion of membrane fusion, with a focus on the role of C-terminal ß-branched residues and a determination of the conformational changes that can occur when TM-TM interactions cannot be released. Third, we will dissect the role of the lipid environment in prefusion F stability in the context of cellular and viral membranes. These important experiments will provide critical new insight into the role of TMDs in regulation of F protein stability and fusion promotion.