HHV-8 vGPCR Signaling in Virus Biology

人疱疹病毒-8（HHV-8）是γ-2疱疹病毒，并且与亚科的许多其他成员一样，是 与瘤形成相关，包括B细胞恶性肿瘤和内皮细胞血管增生性疾病。 病毒G蛋白偶联受体（vGPCR）是参与病毒发病机制的HHV-8蛋白之一 由开放阅读框（ORF）74编码。受体影响细胞增殖和转化， 体外和体内肿瘤发生和血管生成。其他疱疹病毒中的GPCR，包括鼠γ- 疱疹病毒-68（MHV-68）已被证明在病毒裂解性复制中起作用，无论是在培养物中还是 in vivo.因此，了解HHV-8 vGPCR信号传导的机制和调控与以下相关： 试图控制病毒复制和相关疾病。vGPCR的先前结构-功能研究 在这个实验室中，确定了参与Ga偶联和选择性的受体残基， Ga亚类激活途径的解离。这项建议的目的是（1）扩大我们以前的 HHV-8 vGPCR的结构-功能研究，以表征GRK介导的 vGPCR信号传导的负调节，和（2）利用工程化的功能改变的vGPCR蛋白， 研究特定信号通路和vGPCR调控机制在病毒复制中的作用。 这些研究将首次解决vGPCR在病毒裂解复制中的功能，并提供 为未来研究vGPCR激活途径的作用提供数据、技术和试剂， KS的体外和体内模型中疾病发展的控制机制。

Human herpesvirus-8 (HHV-8) is a gamma-2 herpesvirus and,like many other members of the subfamily, is associated with neoplasia, including B cell malignancies and endothelial cell angioproliferative diseases. One of the HHV-8 proteins implicated in viral pathogenesis is the viral G protein-coupled receptor (vGPCR) encoded by open reading frame (ORF) 74. The receptor effects cellular proliferation and transformation in vitro and tumorigenesis and angiogenesis in vivo. GPCRs in other herpesviruses, including murine gamma- herpesvirus-68 (MHV-68), have been demonstrated to play roles in virus lytic replication, both in culture and in vivo. Understanding the mechanisms and regulation of HHV-8 vGPCR signaling is therefore relevant to attempts to control virus replication and associated disease. Previous structure-function studies of vGPCR in this laboratory identified receptor residues involved in Ga coupling and selectivity, and enabled dissociation of Ga subclass-activated pathways. The aims of this proposal are (1) to extend our previous structure-function studies of HHV-8 vGPCR to characterize the structural requirements for GRK-mediated negative regulation of vGPCR signaling, and (2) to utilize engineered functionally altered vGPCR proteins to investigate the roles of particular signaling pathways and vGPCR-regulatory mechanisms in virus replication. These studies will, for the first time, address the function of vGPCR in virus lytic replication, and provide enabling data, technology and reagents for future studies of the role of vGPCR-activated pathways and control mechanisms in disease development in in vitro and in vivo models of KS.