HHV-8 vGPCR Signaling in Virus Biology

描述(申请人提供)：人类疱疹病毒-8(HHV-8)是一种伽马-2疱疹病毒，与亚家族的许多其他成员一样，与肿瘤有关，包括B细胞恶性肿瘤和内皮细胞血管增生性疾病。HHV-8病毒致病蛋白之一是由开放阅读框架(ORF)74编码的病毒G蛋白偶联受体(VGPCR)。该受体在体外影响细胞的增殖和转化，在体内影响肿瘤的形成和血管生成。其他疱疹病毒中的GPCRs，包括小鼠伽玛-疱疹病毒-68(MHV-68)，已被证明在病毒裂解复制中发挥作用，无论是在培养中还是在体内。因此，了解HHV-8vGPCR信号的机制和调节对于控制病毒复制和相关疾病的尝试是相关的。本实验室以前对vGPCR的结构和功能的研究发现，受体残基参与了GA偶联和选择性，并使GA亚类激活的通路能够解离。这一建议的目的是(1)扩展我们先前对HHV-8vGPCR的结构-功能研究，以表征GRK介导的vGPCR信号负调控的结构要求，以及(2)利用功能改变的工程vGPCR蛋白来研究特定的信号通路和vGPCR调控机制在病毒复制中的作用。这些研究将首次阐明vGPCR在病毒裂解复制中的作用，并为进一步研究vGPCR激活的途径和控制机制在KS体外和体内模型中的疾病发展提供可能的数据、技术和试剂。

DESCRIPTION (provided by applicant): 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.