Regulation of Actin Dynamics During T Cell Activation

描述(由申请人提供)：实验和临床研究强调T细胞在增强抗肿瘤反应中的潜力及其在炎症中的病理作用。因此，旨在了解T细胞激活过程中使用的信号转导机制的努力为开发策略以在需要时从药物或基因上增强或抑制T细胞功能提供了基础。肌动蛋白细胞骨架及其调节因子在T细胞受体(TCR)、共刺激和整合素介导的信号转导中起关键作用。我们的初步数据表明，Dynamin 2、Vav1和WAVE2这三种肌动蛋白调节蛋白的动态相互作用影响TCR参与后细胞骨架的变化和激活级联反应。这项建议中概述的机械实验将通过检验以下中心假设来从功能上表征dy2及其效应器分子在TCR交联后肌动蛋白介导的过程中的作用：dy2通过作为在T细胞-ARC接触部位组装肌动蛋白调节蛋白的分子支架来促进T细胞的激活。此外，我们认为，Vav1在免疫突触上的定位需要新的dy2-Vav1相互作用，在那里它将激活其靶分子rac1。此外，我们提供的证据表明，在T细胞激活中起关键作用的DYN2靶标是由rac1调节的WAVE2复合体。为了验证我们的中心假设，我们将(1)确定Dynamin 2在T细胞激活中的作用；(2)确定Vav1调节Dynamin 2介导的调节事件的机制；(3)确定Abi-WAVE2复合体在T细胞中的作用。总之，这些研究将为理解参与调节T细胞激活的分子事件提供实验基础，并将在更广泛的背景下促进我们对淋巴细胞激活过程中涉及肌动蛋白细胞骨架动力学的基本过程的理解。

DESCRIPTION (provided by applicant): Experimental and clinical studies highlight the potential for T cells in enhancing anti-tumor response and their pathological role in inflammation. Thus, efforts aimed at understanding the signal transduction mechanisms utilized during T cell activation provide a foundation for developing strategies to pharmacologically or genetically enhance or suppress T cell functions when needed. The actin cytoskeleton and its regulators play a key role in T-cell receptor (TCR)-, costimulatory-, and integrin-mediated signaling. Our preliminary data suggest that the dynamic interaction of three actin-regulatory proteins, Dynamin 2, Vav1 and WAVE2 influence cytoskeletal changes and the activation of kinase cascades following TCR engagement. The mechanistic experiments outlined in this proposal will functionally characterize the role of Dyn2 and its effector molecules in actin-mediated processes following TCR crosslinking by testing the central hypothesis that: Dyn2 contributes to T cell activation by functioning as a molecular scaffold for the assembly of actin regulatory proteins at the T cell - ARC contact site. In addition, we propose that the novel Dyn2-Vav1 interaction is required for the localization of Vav1 to the immunological synapse where it will activate its target molecule Rac1. Moreover, we provide evidence that identifies a role for the Rac1-regulated WAVE2 complex as a target of Dyn2 that plays a key role in T cell activation. In order to test our central hypothesis, we will (1) Determine the role of Dynamin 2 in T cell activation; (2) Determine the mechanism by which Vav1 regulates Dynamin 2-mediated regulatory events; and (3) Determine the role of the Abi-WAVE2 complex in T cells. Together, these studies will provide an experimental basis for understanding the molecular events that are involved in the regulation of T cell activation, and will in a broader context, advance our understanding of fundamental processes involved in actin cytoskeletal dynamics during lymphocyte activation.