Herpesvirus saimiri TIP

描述(申请人提供)：拟议的研究旨在研究疱疹病毒塞米里(HVS)酪氨酸激酶相互作用蛋白(TIP)诱导的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持续感染的建立和维持，并在培养的初级淋巴细胞永生化和非自然宿主普通绒猴的淋巴瘤诱导中是必需的。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。根据我们的初步结果，我们假设人类免疫球蛋白Tip的信号和靶向功能依赖于一系列的功能和基因上可分离的机制来全面抑制TCR信号转导：TIP与Lck的相互作用抑制TCR复合体并将其招募到脂筏中，Tip与p80的相互作用随后诱导脂筏的聚集和内化，TIP与逆聚体的相互作用最终将TCR复合体定向到溶酶体进行降解。另一方面，Lck对Tip的磷酸化招募并激活STAT/NMI转录因子复合体，以提供生存信号。因此，TiP的表达不仅可以解除对TCR信号转导和表达的调控，还可以激活STAT介导的生存信号，从而建立和维持松鼠猴的病毒持续感染，并在常见的绒猴淋巴增殖性疾病的发生发展中发挥作用。我们的生化和细胞生物学研究将更详细地确定TIP用于解除对TCR信号转导的调控和诱导STAT介导的淋巴细胞激活的机制。为了将TIP在细胞信号转导中的作用与病毒致病机制和持续感染联系起来，我们将测试含有WT TIP或其突变体的重组人类免疫缺陷病毒是否能够诱导普通绒猴的原始淋巴样细胞永生化和淋巴瘤，并建立松鼠猴的持续感染模型。在建立了良好的体外和体内实验条件的基础上，本研究将详细阐述TiP在细胞信号转导的放松调控和生存信号的诱导中的作用，从而促进病毒的持续存在和致病。

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.