Mechanisms of Ras signaling in single synapses

摘要 Ras超家族的小GTPase蛋白对突触所必需的许多神经元过程都是重要的 可塑性，包括长期突触增强，新突触的形成，以及细胞兴奋性的调节。 在RAS超家族中，一个特别重要的亚家族是一组被称为RAB的蛋白质，它调节 突触可塑性过程中膜和谷氨酸受体的运输。与……的重要性一致 Rab信号在突触可塑性中的作用，异常的Rab信号与引起认知障碍的疾病有关 学习障碍和学习障碍。然而，Rab蛋白在突触过程中的时空动态 树突棘的可塑性及其确切功能尚不完全清楚。因此，目标是 本研究旨在阐明树突棘中Rab蛋白在突触可塑性过程中的机制和作用。 我们已经开发出高灵敏的生物传感器来检测Rab4、Rab5、Rab8和Rab10的成像活性。我们的 初步数据表明，RAB蛋白在不同的时间窗口中被激活或失活 突触可塑性。根据这些初步数据和之前的文献，我们的中心假设是Rab 蛋白质调节不同内膜室之间的膜转运平衡 树突棘调节树突棘的功能和结构可塑性，而这反过来又调节 突触可塑性、学习和记忆。在本项目中，我们将进一步分析RAB介导的信号传递 蛋白质及其在突触可塑性过程中膜和受体运输中的作用。我们的具体目标是 1)揭示突触可塑性过程中RAB活性的时空动态，并识别上游 Rab蛋白的调节，2)阐明Rab蛋白在脊椎结构和功能中的作用 突触可塑性过程中的膜转运，3)鉴定Rab蛋白在谷氨酸受体中的作用 使用生化分析的内化和循环，以及4)阐明Rab蛋白在突触中的作用 可塑性、学习和记忆。这项工作将增进我们对Rab如何将钙与 突触可塑性、学习和记忆。

ABSTRACT The Ras superfamily of small GTPase proteins is important for many neuronal processes essential to synaptic plasticity, including long-term synaptic potentiation, formation of new synapses, and regulation of cell excitability. Among the Ras superfamily, a particularly important subfamily is a group of proteins called Rab, which regulate trafficking of membrane and glutamate receptors during synaptic plasticity. Consistent with the importance of Rab signaling in synaptic plasticity, abnormal Rab signaling is associated with diseases causing cognitive impairments and learning deficits. However, the spatiotemporal dynamics of Rab proteins during synaptic plasticity and their exact functions at individual dendritic spines are not fully understood. Thus, the objective of this project is to elucidate the mechanisms and roles of Rab protiens in dendritic spines during synaptic plasticity. We have developed highly sensitive biosensors for imaging activity of Rab4, Rab5, Rab8 and Rab10. Our preliminary data suggest that Rab proteins are activated or inactivated in different temporal windows during synaptic plasticity. Based on these preliminary data and previous literatures, our central hypothesis is that Rab proteins regulate the balance of membrane trafficking between different internal membrane compartments in dendritic spines to regulate functional and structural plasticity of dendritic spines, and this in turn modulates synaptic plasticity, learning and memory. In this project, we will further analyze signaling mediated by Rab proteins and their roles in trafficking of membrane and receptors during synaptic plasticity. Our specific aims are 1) to reveal the spatiotemporal dynamics of Rab activity during synaptic plasticity and to identify upstream regulators of Rab proteins, 2) to elucidate the roles of Rab proteins in structure and function of spines and in membrane trafficking during synaptic plasticity, 3) to identify the roles of Rab proteins in glutamate receptor internalization and recycling using biochemical assays, and 4) to elucidate the roles of Rab proteins in synaptic plasticity, learning and memory. This work will advance our understanding of how Rab couples calcium with synaptic plasticity, learning and memory.