Functional roles of lipid domains in B cell signaling

项目总结 B细胞感知和操纵众多细胞表面受体的横向组织，以促进 它们在免疫系统中的功能作用。受体聚集作为信号启动的一种物理模式是 在B细胞中普遍存在，但相应的感知和控制聚集的一般机制 胞内成分尚不清楚。对聚集性B细胞信号转导机制的理解 事件是必不可少的，因为它们在免疫功能中发挥着重要作用，缺陷会导致疾病，如 癌症和免疫缺陷以及广泛使用的免疫治疗药物利用了这些机制。目标是 这项工作的重点是开发一个框架，描述受体组织是如何与受体功能联系在一起的 B细胞表面受体的一类，用有序的膜结构域进行划分。工作假说是 有序结构域稳定为启动和调节不同的B蛋白提供了基本范式 细胞信号反应。这项拟议的研究是由B细胞受体(BCR)预测模型指导的 在上一个资金周期中开发的信号传递，并在实验中测试了该模型的扩展预测 不仅仅是BCR信号。在广泛的初步数据指导下，将追求三个具体目标：1) 建立聚集B细胞表面蛋白激活信号的一般机制，2)调节B细胞 通过光遗传控制支架元件的细胞膜组织和信号传递，以及3)识别 膜结构域在bcr信号中的免疫调节作用。第一个目标是建立一个将军 一种传感机制，描述了通过聚集15个以上不同的B细胞表面蛋白而启动的信号 它们在文献中被报告为具有有序结构域的分区。第二个目标将定义脚手架如何 分子模板功能膜组织跨质膜小叶及其贡献 这种对配体非依赖信号的影响。第三个目标将确定并隔离类似阶段的角色 膜结构域在下游细胞决策中发挥作用，通过调制通过 BCR。所有目标都使用定量超分辨率荧光定位显微镜技术 在化学固定细胞和活细胞中检测微妙的区域介导的相互作用的灵敏度。建议的工作是 创新性，因为它应用了膜组织的预测模型，并利用了 超分辨率成像、生物传感器技术和光遗传学。一种具有广泛适用性的机械模型 B细胞信号将推动基础B细胞生物学的未来进展，阐明 几种广泛使用的B细胞靶向药物的疗效，并为免疫治疗提供了新的途径 疾病。

PROJECT SUMMARY B cells sense and manipulate the lateral organization of numerous cell surface receptors in order to facilitate their functional roles within the immune system. Receptor clustering as a physical mode of signal initiation is ubiquitous in B cells, yet the corresponding general mechanisms by which clustering is sensed and controlled by intracellular components are unknown. A mechanistic understanding of clustering-mediated B cell signaling events is essential because they play important roles in immune function, defects lead to diseases such as cancer and immunodeficiency, and widely used immunotherapeutic drugs exploit these mechanisms. The goal of this work is to develop a framework that describes how receptor organization is tied to receptor functions for the class of B cell surface receptors that partition with ordered membrane domains. The working hypothesis is that ordered domain stabilization provides a fundamental paradigm for the initiation and regulation of diverse B cell signaling responses. The proposed research is guided by a predictive model of B cell receptor (BCR) signaling developed in the previous funding cycle and experimentally tests predictions of this model extended beyond BCR signaling alone. Guided by extensive preliminary data, three specific aims will be pursued: 1) Establish a generalized mechanism of signaling activated by clustering B cell surface proteins, 2) Modulate B cell membrane organization and signaling through optogenetic control of scaffolding elements, and 3) Identify immunomodulatory roles facilitated by membrane domains in BCR signaling. The first aim will establish a general sensing mechanism that describes signals initiated via clustering of more than 15 distinct B cell surface proteins that are reported in the literature to partition with ordered domains. The second aim will define how scaffolding elements template functional membrane organization that spans plasma membrane leaflets and the contribution of this effect to ligand-independent signaling. The third aim will identify and isolate the roles that phase-like membrane domains play in downstream cellular decision-making by modulating signals initiated through the BCR. All aims use quantitative super-resolution fluorescence localization microscopy techniques with the sensitivity to detect subtle domain-mediated interactions in chemically fixed and live cells. The proposed work is innovative because it applies predictive models of membrane organization and exploits recent advances in super-resolution imaging, biosensor technology, and optogenetics. A broadly applicable mechanistic model for B cell signaling will drive future advances in basic B cell biology, elucidate the mechanisms underlying the efficacy of several widely used B cell-targeted drugs, and provide new approaches for the treatment of immune diseases.