HIV-1 Vif in AIDS-Related Malignancies

 描述(申请人提供)：HIV-1VIF在艾滋病相关恶性肿瘤中摘要病毒感染性因子(VIF)是一种辅助蛋白，几乎在包括HV-1在内的所有慢病毒中都存在，并且对于在CD4+T细胞中的生产性感染是必不可少的。它的典型功能围绕APOBEC3-Vif轴，Vif多泛素化和靶向APOBEC3蛋白降解，通过劫持转录因子CBF？和包含CUL5、ELOB、ELOC和RBX2的E3泛素连接酶。然而，大量数据表明，Vif具有替代功能。最近，我们发现Vif还与自噬相关蛋白AMBRA1相互作用，这种Vif-AMBRA1相互作用在HIV-1、SIV、FIV、BIV和MVV之间是保守的。仅保守性本身就提出了一种新的替代VIF功能。VIF很可能劫持AMBRA1在细胞凋亡和自噬中的正常功能，并形成E3泛素连接酶来降解细胞蛋白质。这项提案的目标1将集中于确定 通过1A)使用有效的串联亲和纯化-质谱法和1B)通过系统截断和定点突变来定位每个组分的相互作用结构域来完成Vif-AMBRA1相互作用复合体。本提案的目的2将通过以下方式来探索Vif-AMBRA1复合体的功能：2A)量化Vif对AMBRA1介导的自噬和细胞凋亡的影响；2B)确定Vif-AMBRA1连接酶复合体的细胞泛素化靶标。本文提出的研究可能为HIV感染过程中肿瘤的发生提供了另一种机制。与所有肿瘤一样，艾滋病相关恶性肿瘤不是一步到位的过程，但宿主蛋白的颠覆和细胞过程的调节等因素的组合在这个复杂的过程中起着重要的作用。

 DESCRIPTION (provided by applicant): HIV-1 Vif in AIDS-Related Malignancies ABSTRACT Viral infectivity factor (Vif) is an accessory protein found in nearly all lentiviruses including HV-1 and is essential for productive infection in CD4+ T cells. Its canonical function revolves around the APOBEC3-Vif axis, whereby Vif polyubiquitinates and targets APOBEC3 proteins for degradation by hijacking the transcription factor CBFß and an E3 ubiquitin ligase containing CUL5, ELOB, ELOC, and RBX2. However, numerous data suggest that Vif possesses alternative functions. Recently, we have found that Vif also interacts with the autophagy-related protein, AMBRA1, and that this Vif-AMBRA1 interaction is conserved among HIV-1, SIV, FIV, BIV, and MVV. Conservation alone suggests a novel alternative Vif function. Vif most likely hijacks AMBRA1 from its normal functions in apoptosis and autophagy and forms an E3 ubiquitin ligase to degrade cellular proteins. Aim 1 of this proposal will focus on identifying the complete Vif-AMBRA1 interacting complex by 1A) using a validated tandem affinity purification-mass spectrometry approach and 1B) mapping the interaction domains of each constituent via systematic truncation and site-directed mutagenesis. Aim 2 of this proposal will explore the function of the Vif-AMBRA1 complex by 2A) quantifying the impact of Vif on AMBRA1- mediated autophagy and apoptosis and 2B) identifying the cellular ubiquitination targets of the Vif-AMBRA1 ligase complex. The studies proposed here may provide an additional mechanism of tumorigenesis during HIV infection. As is with all tumors, no one-step process directly explains AIDS-related malignancies, but combinations of factors such as subversion of host proteins and modulation of cellular processes serve as important steps in this complex process.