THE ROLE OF HIV-1 VPU IN THE REGULATION OF CD40

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 该项目的总体目标是了解HIV-1蛋白Vpu在HIV发病机制中的作用。最初的目的是了解Vpu如何调节细胞因子受体CD 40的表达。 我们的研究表明，Vpu对CD 40的影响是由于下游的其他途径的调节。因此，我们进行了蛋白质组学，以确定新的细胞蛋白影响的Vpu在β TrCP依赖性的方式，并确定BST-2作为一个重要的Vpu目标。 这一点很重要，因为BST-2最近被鉴定为限制HIV从感染细胞释放的宿主抗病毒因子。 BST-2被重新命名为tetherin，独立的研究证实了我们的发现，Vpu拮抗BST-2。 因此，我们重新调整了我们的项目目标，调查Vpu介导的BST-2下调的机制和生物学后果，并在这方面取得了重大进展。 我们发现Vpu通过内体/溶酶体途径与BST-2相互作用并靶向BST-2降解，并且β TrCP是降解所需的，并已发表了这项工作。 我们在以下领域取得了额外的进展：i）绘制克服BST-2对病毒排出的限制所必需的Vpu区域; ii）表征泛素在Vpu介导的BST-2降解中的作用; iii）鉴定参与病毒体束缚或充当Vpu功能的接头的BST-2结合配偶体。 这一进展使我们能够提交新的R 01申请“BST-2的Vpu药物降解表征”。 我们的BST-2试剂也被用于合作研究，以检测BST-2对KSHV K5蛋白的拮抗作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of this project is to understand the role of the HIV-1 protein Vpu in HIV pathogenesis. The original aim was to understand how Vpu modulates expression of the cytokine receptor CD40. Our studies showed that Vpu's effect on CD40 was due to downstream modulation of other pathways. We thus performed proteomics to identify novel cellular proteins affected by Vpu in a beta TrCP-dependent manner, and identified BST-2 as a significant Vpu target. This was important, since BST-2, was recently identified as a host antiviral factor that restricts the release of HIV from infected cells. BST-2 was renamed tetherin and independent studies confirmed our finding that Vpu antagonizes BST-2. We thus refocused our project goals to investigate the mechanisms and biological consequences of Vpu-mediated BST-2 downregulation and have made significant progress in this regards. We found that Vpu interacts with and targets BST-2 for degradation by an endosomal/lysosomal pathway and that beta TrCP is required for degradation and have published this work. We have made additional progress in the following areas i) mapping Vpu regions necessary for overcoming BST-2 restriction of viral egress; ii) characterizing the role of ubiquitin in Vpu-mediated BST-2 degradation; iii) identifying BST-2 binding partners involved in virion tethering or acting as adapters for Vpu function. This progress has allowed us submit a new R01 application "Characterization of Vpu-medicated Degradation of BST-2". Our BST-2 reagents were also used in collaborative work to examine BST-2 antagonism by the KSHV K5 protein that is now published.