Regulation of NK Cell Function by Vav-family Proteins

Vav 家族蛋白对 NK 细胞功能的调节

• 批准号: 7022275
• 负责人: WOJCIECH A SWAT
• 金额: $ 22.41万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7022275
• 关键词: bioassay; biological signal transduction; cell mediated cytotoxicity; cellular immunity; gene mutation; genetically modified animals; guanine nucleotide exchange factors; immunologic receptors; immunoregulation; laboratory mouse; leukocyte activation /transformation; membrane proteins; microorganism immunology; natural killer cells; neoplasm /cancer immunology; phosphorylation; site directed mutagenesis; tissue /cell culture; tyrosine

DESCRIPTION (provided by applicant): Vav proteins are guanine nucleotide exchange factors and molecular adaptors that play a key role in signal transduction of lymphocyte antigen receptors. Several recent studies have also implicated Vav1 in natural killer (NK) cell-mediated cytotoxicity of tumor cells. However, whether Vav1 effects all NK cell activating pathways is not known, and it is possible that other Vav family molecules are involved in NK cell triggering. NK cells recognize tumor or virally-infected cells through multiple activating receptors with diverse structures, specificities and signaling adaptors. The activating NK cell receptor NKG2D recognizes endogenous major histocompatibility complex (MHC) class I-related molecules expressed at high levels primarily in virally infected and tumor cells while Ly49H mediates selective recognition of m157, a murine cytomegalovirus (MCMV)-encoded class I-like molecule that is expressed on infected cells. Both NKG2D and Ly49H deliver stimulatory signals which trigger secretion of IFN-? and release of cytotoxic granules that contain perforin and granzymes. However, it is not know exactly how such stimulatory signals are transduced inside the NK cells. NKG2D and Ly49D/H lack cytoplasmic signaling elements and can deliver stimulatory signals only by associating with transmembrane adaptor proteins. Ly49D and Ly49H signal through DAP12 (also called KARAP) which contains immunoreceptor tyrosine-based activation motifs (ITAM) that are phosphorylated and function as docking sites for Syk and ZAP70 protein tyrosine kinases. In contrast, NKG2D signals through DAP10, a unique adapter that contains a YxNM motif which recruits phosphatidyl inositol 3-kinase (PI3-K) and Grb-2. As part of our preliminary studies for this proposal we generated mice lacking the individual, or all, Vavfamily proteins and began to examine the potential contribution of these proteins to NK cell cytotoxicity. Intriguingly, these data indicate that Vav is essential for DAP10- but not for DAP12-mediated natural cytotoxicity. Thus, these data suggest a new paradigm regarding the utilization of Vav in activation of natural cytotoxicity downstream of NK cell surface receptors associated with non-ITAM- vs. ITAM-containing adaptors. Here, we propose to use several in vitro and in vivo approaches to determine Vav mechanism in NK cell function and development of natural cytotoxicity against virally-infected and tumor cells.

描述（由申请人提供）：VAV蛋白是鸟嘌呤核苷酸交换因子和分子适配器，它们在淋巴细胞抗原受体的信号转导中起关键作用。最近的一些研究也暗示了VAV1在肿瘤细胞的天然杀伤（NK）细胞介导的细胞毒性中。但是，VAV1是否影响所有NK细胞激活途径尚不清楚，并且其他VAV家族分子可能参与NK细胞触发。 NK细胞通过具有多种结构，特异性和信号适配器的多种激活受体识别肿瘤或病毒感染的细胞。 The activating NK cell receptor NKG2D recognizes endogenous major histocompatibility complex (MHC) class I-related molecules expressed at high levels primarily in virally infected and tumor cells while Ly49H mediates selective recognition of m157, a murine cytomegalovirus (MCMV)-encoded class I-like molecule that is expressed on infected cells. NKG2D和LY49H都提供刺激信号，这会触发IFN-的分泌？并释放含有穿孔蛋白和颗粒状的细胞毒性颗粒。但是，不确定在NK细胞内部如何转导这种刺激信号。 NKG2D和LY49D/H缺乏细胞质信号传导元件，只能通过与跨膜衔接蛋白相关来传递刺激信号。 LY49D和LY49H信号通过DAP12（也称为KARAP），其中包含基于免疫感受器酪氨酸的活化基序（ITAM），这些基序（ITAM）是磷酸化的，并用作SYK和ZAP70蛋白质酪氨酸酪氨酸激酶的对接位点。相反，NKG2D通过DAP10信号，DAP10是一个唯一的适配器，其中包含YXNM基序，该基序募集了磷脂酰肌醇3-激酶（PI3-K）和GRB-2。 作为我们对该提案的初步研究的一部分，我们产生了缺乏个体或全部vavfamily蛋白质的小鼠，并开始研究这些蛋白质对NK细胞毒性的潜在贡献。有趣的是，这些数据表明VAV对于DAP10至关重要，但对于DAP12介导的自然细胞毒性不是必需的。因此，这些数据提出了关于VAV在激活NK细胞表面受体下游激活与非iTam-in-Itam-与ITAM含ITAM的适配器有关的新范式的新范式。在这里，我们建议使用几种体外和体内方法来确定NK细胞功能中的VAV机制以及针对病毒感染和肿瘤细胞的自然细胞毒性的发展。