Mechanisms that determine subcellular sites of HIV-1 assembly

标题：确定HIV-1组装的亚细胞位置的机制 摘要/摘要： 艾滋病的病原体HIV-1的病毒颗粒组装发生在质膜上 大多数细胞类型包括自然宿主T细胞。这一过程是由病毒结构蛋白Gag驱动的。这个N- Gag的末端矩阵(MA)结构域决定了Gag对PM的定位，从而决定了病毒在PM的组装体量 通过N-末端肉豆蔻基部分和高碱性区域(HBr)介导GAG的膜结合 酸性脂类。Hbr与质膜特异性酸性磷脂PI(4，5)P2的结合是质膜定位Gag的关键 和高效的病毒释放。值得注意的是，体外和基于细胞的研究表明，MA HBr也与 TRNAs抑制Gag与非PI(4，5)P2酸性脂类的结合，提示tRNAs是一种新的寄主因子 它调节MA-膜的相互作用。然而，tRNA-MA HBR相互作用的分子决定因素 并通过与PI(4，5)P2的相互作用逆转其作用，PI(4，5)P2的组合调节PM特异性的GAG定位， 仍有待阐明。此外，这些互动是如何开始的，以及这些互动对 对子代病毒粒子末端的性质知之甚少。TRNA与MA HBR的结合最有可能 由于翻译机构之外的tRNA可获得性有限，因此发生在翻译站点。然而，几乎没有 已知GAG翻译的亚细胞位置，在那里GAG开始向PM移动在首相面前，恶作剧 多聚体可能会造成酸性脂质的积累，但它对后代病毒粒子的能力产生了影响 传播到未感染细胞的情况仍不清楚。 我们的长期目标是阐明确定HIV-1组装位点的机制，并使用 开发抗病毒策略的知识。我们在此应用程序中的中心假设是MA HBR 在翻译过程中与tRNAs的相互作用，以及与酸性脂质的相互作用，决定了亚细胞Gag 子代病毒粒子的定位和性质。为了验证这一假设，我们计划：1)鉴定分子 MA HBR与tRNAs相互作用的决定因素及其被PI(4，5)P2逆转；2)识别 抑制PI(4，5)P2非依赖性膜结合，但允许PI(4，5)P2介导的逆转；3)检查 GAG在翻译过程中与tRNA结合的可能性；以及4)检查酸性脂质的影响 病毒聚集点对病毒粒子性质的影响。概述了从实验中获得的知识 这项提案可能有助于我们开发针对调节GAG的机制的抗病毒策略 定位到PM，从而抑制细胞外病毒的释放和传播。

Title: Mechanisms that determine subcellular sites of HIV-1 assembly Summary/Abstract: Virus particle assembly of HIV-1, the causative agent of AIDS, takes place at the plasma membrane (PM) in most cell types including natural host T cells. This process is driven by a viral structural protein Gag. The N- terminal matrix (MA) domain of Gag determines Gag localization to and hence virus assembly at the PM. MA mediates membrane binding of Gag via N-terminal myristoyl moiety and a highly basic region (HBR) that binds acidic lipids. Binding of HBR to a PM-specific acidic phospholipid PI(4,5)P2 is critical for PM localization of Gag and efficient virus release. Notably, in vitro and cell-based studies showed that MA HBR also interacts with tRNAs, which suppress binding of Gag to non-PI(4,5)P2 acidic lipids, suggesting tRNAs as a new host factor that regulates MA-membrane interactions. However, molecular determinants for the tRNA-MA HBR interaction and its reversal by the interaction with PI(4,5)P2, combination of which regulates PM-specific Gag localization, remain to be elucidated. Moreover, how these interactions begin and what effect these interactions have on the property of progeny virions at the end are poorly understood. Binding of tRNAs to MA HBR is most likely to occur at translation sites due to limited availability of tRNAs outside of the translation machinery. However, little is known about subcellular sites of Gag translation, where Gag begins its movement to the PM. At the PM, Gag multimerization is likely to create accumulation of acidic lipids, but its impact on the ability of progeny virions to spread to uninfected cells remains unknown. Our long-term goal is to elucidate mechanisms that determine sites of HIV-1 assembly and to use the knowledge for developing antiviral strategies. Our central hypothesis in this application is that MA HBR interactions with tRNAs, which begin during translation, and with acidic lipids determine subcellular Gag localization and the properties of progeny virions. To test this hypothesis, we plan to: 1) identify molecular determinants for interaction of MA HBR with tRNAs and its reversal by PI(4,5)P2; 2) identify tRNAs that suppress PI(4,5)P2-independent membrane binding but allow PI(4,5)P2-mediated reversal; 3) examine the possibility that Gag associates with tRNA during translation; and 4) examine the effect of acidic lipid accumulation at virus assembly sites on the virion properties. The knowledge gained from experiments outlined in this proposal will likely help us develop antiviral strategies that target mechanisms regulating Gag localization to the PM, thereby inhibiting extracellular virus release and spread.