Cellular Determinants and Function Consequences of PP2A-B56 Degradation by HIV-1 Vif

项目总结 HIV-1 Vif蛋白在感染后期表达，具有众所周知的泛素化和 降解APOBEC3家族中的蛋白质，从而中和其抗病毒活性。最近，又增加了一项 我们和其他人描述了HIV-1 Vif泛素化和降解蛋白磷酸酶2A的功能 含有B56家族调节亚基的全酶(PP2A-B56)。Vif介导的PP2A-的保守性 B56在全球流通的HIV-1亚型中的降解表明它在功能上是重要的。 然而，在理解PP2A-B56降解赋予 对HIV-1的健身优势。此外，与APOBEC3降解相反，宿主细胞决定因素 Vif介导的泛素化和PP2A-B56降解所需的蛋白质尚未定义。 在这个项目中，我们的目标是通过定义细胞决定因素和功能来解决这些理解上的差距 HIV-1 Vif对PP2A-B56降解的影响在目标1中，我们将应用无偏见的蛋白质相互作用技术 目的：确定PP2A-B56被Vif降解时与其相互作用的蛋白质。在目标2中，我们将进行基因组- 广泛的CRISPR/Cas9遗传筛选，以确定调控APOBEC3和PP2A-B56降解的基因。在AIM 3，将测试PP2A-B56调节的单个磷酸化位点在HIV-1初级复制中的影响 CD4+T细胞。该项目的成功完成将促进对Vif-PP2A-B56信号的理解 Axis，可能导致针对晚期的新型抗逆转录病毒疗法的开发 HIV-1感染的过程。

PROJECT SUMMARY The HIV-1 Vif protein is expressed late during infection and has a well-described function to ubiquitinate and degrade proteins in the APOBEC3 family, thus neutralizing their antiviral activities. More recently, an additional function of HIV-1 Vif was described by us and others to ubiquitinate and degrade protein phosphatase 2A holoenzymes containing B56 family regulatory subunits (PP2A-B56). The conservation of Vif-mediated PP2A- B56 degradation throughout globally circulating HIV-1 subtypes suggests that it is functionally important. However, there remains a gap in understanding the mechanisms by which PP2A-B56 degradation confers a fitness advantage to HIV-1. Furthermore, in contrast to APOBEC3 degradation, the host cellular determinants required for Vif-mediated ubiquitination and degradation of PP2A-B56 are undefined. In this project, we aim to address these gaps in understanding by defining the cellular determinants and functional effects of PP2A-B56 degradation by HIV-1 Vif. In Aim 1, we will apply unbiased protein interaction technologies to determine proteins interacting with PP2A-B56 while it is degraded by Vif. In Aim 2, we will carry out a genome- wide CRISPR/Cas9 genetic screen to identify genes regulating APOBEC3 and PP2A-B56 degradation. In Aim 3, will test the impact of individual phosphorylation sites regulated by PP2A-B56 in HIV-1 replication in primary CD4+ T cells. Successful completion of this project will advance understanding of the Vif-PP2A-B56 signaling axis, potentially leading towards the development of novel classes of antiretroviral therapies that target late processes of HIV-1 infection.