Late Events in Retrovirus Assembly

描述（由申请人提供）：在本竞争性续展申请中，我们请求支持我们对逆转录病毒组装晚期事件的研究。在上一个资助周期中，我们确定并表征了几种细胞蛋白，这些蛋白通过病毒晚期出芽（L）结构域被招募到逆转录病毒组装位点。这些蛋白质是（i）E类空泡蛋白分选（VPS）途径的组分，其通常参与内体和多泡体（MVB）的操纵，或（ii）泛素连接酶。对于这些因素中的几个，我们能够证明在感染性逆转录病毒颗粒的释放中起关键作用。然而，仍然存在一些机制问题，最近我们已经确定了额外的细胞因子，似乎很可能参与逆转录病毒颗粒的构建和释放的后期阶段，和/或内体/MVB生物合成。在下一个资助期内，我们将试图阐明以前定义和新发现的细胞因子如何参与逆转录病毒组装的后期阶段和相关的细胞功能，通过追求两个具体的目标。具体目标1是了解特定的内体蛋白如何被纳入HIV-1颗粒及其在产生感染性病毒粒子中的作用。具体目标2是确定泛素，泛素连接酶和新的泛素连接酶结合蛋白的作用，发现在以前的资助期间，在逆转录病毒出芽和运输的内吞蛋白。这两个目标的实现将使我们的长期目标取得重大进展，即了解细胞和病毒因子如何合作构建完整的感染性逆转录病毒颗粒。了解这些事件可能会提供新的机会来干预这些过程，以治疗由HIV和其他包膜病毒引起的疾病。公共卫生相关性：许多包膜病毒，例如HIV-1，是威胁生命的感染的原因。为了在细胞间传播，它们利用细胞蛋白来促进精确组装的病毒颗粒的释放。了解这个系统是如何工作的，可以为靶向治疗提供干预机会。

DESCRIPTION (provided by applicant): In this competing renewal application we request support for our studies on late events in retrovirus assembly. In the previous funding cycle, we identified and characterized several cellular proteins that are recruited to sites of retrovirus assembly by viral late budding (L)-domains. These proteins are either (i) components of the class E vacuolar protein sorting (VPS) pathway that is normally involved in the manipulation of endosomes and multivesicular bodies (MVB) or (ii) ubiquitin ligases. For several of these factors we were able to demonstrate a critical role in the release of infectious retroviral particles. Several mechanistic questions remain, however, and recently we have identified additional cellular factors that seem very likely to be involved in the late stages of the construction and release of retrovirus particles, and/or endosome/MVB biogenesis. In the next grant period, we will attempt to elucidate how previously defined and newly identified cellular factors participate in the late stages of retrovirus assembly and related cellular functions by pursuing two specific aims. Specific Aim 1 is to understand how specific endosomal proteins are incorporated into HIV-1 particles and their role in generating infectious virions. Specific aim 2 is to determine the role of ubiquitin, ubiquitin ligases and novel ubiquitin ligase binding proteins, discovered during the previous funding period, in retroviral budding and trafficking of endocytosed proteins. Execution of these two aims should result in significant progress toward our long term goal of understanding how cellular and viral factors cooperate in the construction of complete, infectious retroviral particles. Understanding these events could potentially provide new opportunities to interfere in these processes for the treatment of diseases caused by HIV and other enveloped viruses. Public health relevance: Many enveloped viruses, for example HIV-1, are responsible for life threatening infections. To spread from cell to cell they make use of cellular proteins to facilitate the release of accurately assembled virus particles. Understanding how this system works could give opportunities to intervene with targeted therapeutics.