Herpesvirus saimiri TIP

描述（由申请人提供）：拟进行的研究旨在研究猴疱疹病毒（HVS）酪氨酸激酶相互作用蛋白（Tip）诱导信号转导的分子机制。到目前为止，我们的工作已经确定HVS Tip参与了自然宿主松鼠猴的持续感染的建立和维持，并且是培养中的原发性淋巴样细胞永生和非自然宿主普通狨猴淋巴瘤诱导所必需的。我们的生化分析还表明，Tip靶向Lck酪氨酸激酶、STAT转录因子、p80内体接头和Vps35逆转录亚基，下调T细胞受体（TCR）信号转导，并引发STAT介导的生存信号。基于我们的初步结果，我们假设HVS Tip的信号和靶向功能依赖于一系列的功能和基因可分离的机制，这些机制全面抑制TCR信号转导：Tip与Lck的相互作用抑制并招募TCR复合物到脂筏中，Tip与p80的相互作用随后诱导脂筏的聚集和内化，Tip与retromer的相互作用最终将TCR复合物引导到溶酶体中进行降解。另一方面，Lck磷酸化Tip可招募并激活STAT/Nmi转录因子复合体，提供生存信号。因此，Tip的表达不仅解除了TCR信号转导和表达的调控，还激活了stat介导的生存信号，从而在松鼠猴中建立和维持病毒持续感染，并促进了普通狨猴淋巴增生性疾病的发展。我们的生化和细胞生物学研究将更详细地定义Tip用于解除TCR信号转导并引发stat介导的淋巴细胞激活的机制。为了将Tip对细胞信号转导的影响与病毒发病机制和持续感染联系起来，我们将测试含有wt Tip或其突变体的重组HVS是否能够在普通狨猴中诱导原发性淋巴样细胞永活和淋巴瘤，并在松鼠猴中建立持续感染。随着体外和体内实验条件的完善，本研究将详细介绍Tip在细胞信号转导的失调和生存信号的诱导中的作用，从而有助于病毒的持续存在和发病机制。

DESCRIPTION (provided by applicant): The proposed research is directed toward investigating the molecular mechanism of signal transduction induced by the herpesvirus saimiri (HVS) tyrosine kinase interacting protein (Tip). Our work to date has defined that HVS Tip is involved in the establishment and maintenance of persistent infection in the natural host, the squirrel monkey, and required for primary lymphoid cell immortalization in culture and lymphoma induction in the non-natural host, the common marmoset. Our biochemical analysis also demonstrates that Tip targets Lck tyrosine kinase, STAT transcription factor, p80 endosomal adaptor, and Vps35 retromer subunit to down regulate T cell receptor (TCR) signal transduction and to elicit STAT-mediated survival signal. Based on our preliminary results, we hypothesize that the signaling and targeting functions of HVS Tip rely on sequential functionally and genetically separable mechanisms that comprehensively inhibit TCR signal transduction: Tip interaction with Lck inhibits and recruits the TCR complex to lipid rafts, Tip interaction with p80 subsequently induces the aggregation and internalization of lipid rafts, and Tip interaction with retromer finally directs TCR complex to the lysosomes for degradation. On the other hand, the phosphorylation of Tip by Lck recruits and activates STAT/Nmi transcription factor complex to provide survival signal. Consequently, Tip expression not only deregulates TCR signal transduction and expression but also activates STAT-mediated survival signaling to establish and maintain viral persistent infection in squirrel monkeys and to contribute to the development of lymphoproliferative disease in common marmosets. Our biochemical and cell biological studies will define in greater detail the mechanisms used by Tip to deregulate TCR signal transduction and to elicit STAT-mediated lymphocyte activation. To correlate the effects of Tip on cellular signal transduction with viral pathogenesis and persistent infection, we will test whether recombinant HVS containing wt Tip or its mutants is able to induce the primary lymphoid cell immortalization and lymphoma in common marmosets and to establish the persistent infection in squirrel monkeys. With well-established in vitro and in vivo experimental conditions, the proposed study will detail the roles of Tip in the deregulation of cellular signal transduction and the induction of survival signal, which consequently contributes to viral persistence and pathogenesis.