The Molecular Mechanisms Contributing to the Specific Localization of HIV-1 Gag to the Plasma Membrane

项目总结/摘要 HIV-1 Gag是一种病毒结构蛋白，其介导病毒颗粒在 感染细胞的质膜。到这个网站的插科打诨交易是其互动的结果 与质膜特异性磷脂PI（4，5）P2。膜结合后， Gag通过衣壳和核衣壳多聚成更高级的结构 结构域，然后驱动新的病毒颗粒从表面萌芽， 宿主细胞尽管MA结构域能够结合任何酸性磷脂、RNA 与MA的结合抑制Gag与不含PI（4，5）P2的膜的结合。 细胞tRNA已被证明是与MA结合的主要RNA种类 加格的领地然而，值得注意的是，我们公布的初步结果显示， 一些tRNA不能抑制GAG-膜结合，而其它tRNA 即使当它们含有PI（4，5）P2时，物种也抑制Gag与膜的缔合。 一旦Gag定位于质膜，则不知道Gag的存在是否与细胞膜上的Gag结合。 PI（4，5）P2足以稳定结合Gag，或者Gag多聚化是否也 有助于这种稳定的联系。此外，尽管我们观察到 结合MA结构域和抑制Gag的膜结合的能力， 不同的tRNA子集，tRNA的分子特征，这是重要的最佳 抑制Gag膜结合仍然不清楚。定义分子间的相互作用 这有助于Gag的稳定膜结合和tRNA与MA的结合 结构域对于理解感染细胞内发生的过程至关重要， 驱动Gag特异性定位于质膜。我们的核心假设是 最佳的抑制性tRNA种类与Gag的MA结构域结合， 翻译位点，确保Gag特异性靶向质膜， PI（4，5）P2和Gag的多聚化促进稳定的膜结合。为了 为了验证我们的假设，我们的目标是确定有助于 Gag在膜上的结合和保留（目标1），并确定如何以及何时 最佳抑制性tRNA种类与Gag的MA结构域结合（Aim 2）。这项工作的完成将澄清分子因素的模型， 对于Gag向质膜的运输和其在质膜上的保留是重要的。 位置.

Project Summary/Abstract HIV-1 Gag is a viral structural protein that mediates virus particle assembly at the plasma membrane of infected cells. Gag trafficking to this site is a result of its interaction with the plasma membrane specific phospholipid PI(4,5)P2. After membrane binding, Gag multimerizes into higher order structures through the capsid and nucleocapsid domains, which then drives the budding of new virus particles from the surface of the host cell. Although the MA domain is capable of binding any acidic phospholipid, RNA binding to MA inhibits the association of Gag with non-PI(4,5)P2-containing membranes. Cellular tRNA has been shown to be the major RNA species that binds to the MA domain of Gag. Notably, however, our published and preliminary results revealed that some tRNAs are incapable of inhibiting Gag-membrane binding, whereas other tRNA species inhibit Gag association with membranes even when they contain PI(4,5)P2. Once Gag localizes to the plasma membrane, it is not known whether the presence of PI(4,5)P2 is sufficient for the stable binding of Gag or whether Gag multimerization also contributes to this stable association. Additionally, although we observed differences in the abilities to bind the MA domain and to inhibit membrane binding of Gag among different tRNA subsets, the molecular features of tRNA that are important for the optimal inhibition of Gag membrane binding are still unclear. Defining the molecular interactions that contribute to the stable membrane binding of Gag and binding of tRNA to the MA domain are essential for understanding the processes that occur within infected cells to drive the specific localization of Gag to the plasma membrane. Our central hypothesis is that optimally inhibitory tRNA species become bound to the MA domain of Gag at the site of translation, ensuring that Gag targets specifically to the plasma membrane where PI(4,5)P2 and the multimerization of Gag promote stable membrane binding. In order to test our hypothesis, we aim to identify the molecular interactions that contribute to the binding and retention of Gag on the membrane (Aim 1) and to determine how and when optimally inhibitory tRNA species become associated with the MA domain of Gag (Aim 2). The completion of this work will clarify the model for the molecular factors that are important for the trafficking of Gag to the plasma membrane and its retention at this location.