Uncovering the role of RIN1 in coordinating AMPA-receptor membrane trafficking and structural spine changes in bidirectional synaptic plasticity

揭示 RIN1 在协调 AMPA 受体膜运输和双向突触可塑性结构脊柱变化中的作用

• 批准号: 186089766
• 负责人: Professorin Dr. Ingrid Ehrlich
• 金额: --
• 依托单位: Institut für Zellbiologie und Immunologie (IZI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/186089766?language=en
• 关键词: Uncovering; role; RIN1; coordinating; AMPA

Synaptic connections in the brain are continuously weakened or strengthened in response to specific changes in neuronal activity. This process, known as synaptic plasticity, is the cellular basis for learning and memory, and is impaired in several brain disorders. Long-term potentiation (LTP) and long-term depression (LTD) are the most studied forms of activity-dependent synaptic plasticity. LTD and LTP are on one hand supported by the highly dynamic and tightly controlled trafficking and synaptic targeting of AMPA-type glutamate receptors (AMPA-Rs), which are the major mediators of fast excitatory transmission in the brain. On the other hand, dynamic remodeling of the actin cytoskeleton supports the accompanying changes in dendritic spine morphology and stability. Despite their important function in synaptic plasticity, the molecular mechanisms coordinating AMPA-R trafficking and cytoskeletal remodeling during synaptic plasticity are still not fully understood. The Ras effector protein RIN1 is highly and specifically expressed in excitatory neurons of the forebrain, particularly in the cerebral cortex, hippocampus, and amygdala. Importantly, RIN1 has a dual role as it enhances signaling of the tyrosine kinases Abl and Arg, which regulate actin cytoskeletal remodeling, and it activates the small GTPase Rab5 to facilitate receptor endocytosis. Recently, in hippocampal neurons we have found that RIN1 destabilizes synaptic connections and is a key player in postsynaptic AMPA receptor endocytosis. We further identified RIN1 to be required for activity-dependent spine plasticity during LTD. Building on our previous body of work, the overarching aim of this project is to gain comprehensive insight in how the dual functions of RIN1 orchestrate AMPA receptor trafficking and activity-dependent structural spine changes during bidirectional synaptic plasticity at excitatory synapses. Towards this end, we will combine a number of state of the art techniques including molecular manipulations of RIN1, biochemical assays, subcellular localization studies, live cell imaging experiments, and electrophysiological recordings. Biochemical studies will address the regulation of RIN1 and its protein-protein interactions. Imaging approaches will unravel plasticity-driven changes in subcellular regulation and activation of downstream signaling pathways, including their contributions to structural plasticity and AMPA-R trafficking. Finally, electrophysiological approaches will interrogate how different RIN1 functions contribute to the regulation of bidirectional synaptic strength in defined hippocampal circuits.

大脑中的突触连接不断减弱或加强，以响应神经元活动的特定变化。这个过程被称为突触可塑性，是学习和记忆的细胞基础，在几种大脑疾病中受损。长时程增强（LTP）和长时程抑制（LTD）是活动依赖性突触可塑性研究最多的形式。LTD和LTP一方面由AMPA型谷氨酸受体（AMPA-R）的高度动态和严格控制的运输和突触靶向支持，AMPA-R是大脑中快速兴奋性传递的主要介质。另一方面，肌动蛋白细胞骨架的动态重塑支持树突棘形态和稳定性的伴随变化。尽管AMPA-R在突触可塑性中起着重要作用，但其在突触可塑性中协调AMPA-R运输和细胞骨架重塑的分子机制仍不完全清楚。Ras效应蛋白RIN 1在前脑的兴奋性神经元中高度特异性表达，特别是在大脑皮层、海马和杏仁核中。重要的是，RIN 1具有双重作用，因为它增强酪氨酸激酶Abl和Arg的信号传导，其调节肌动蛋白细胞骨架重塑，并且它激活小GTTR Rab 5以促进受体内吞作用。最近，在海马神经元中，我们发现RIN 1使突触连接不稳定，并且是突触后AMPA受体内吞作用的关键参与者。我们进一步确定了RIN 1需要在有限公司的活动依赖性脊柱可塑性的基础上，我们以前的工作机构，这个项目的首要目标是获得全面的洞察力，在双向突触可塑性在兴奋性突触的双重功能RIN 1编排AMPA受体贩运和活动依赖性结构脊柱的变化。为此，我们将结合联合收割机的最先进的技术，包括RIN 1的分子操作，生化测定，亚细胞定位研究，活细胞成像实验，和电生理记录。生物化学研究将解决RIN 1及其蛋白质-蛋白质相互作用的调节。成像方法将揭示亚细胞调节和下游信号通路激活的可塑性驱动的变化，包括它们对结构可塑性和AMPA-R运输的贡献。最后，电生理学方法将询问不同的RIN 1功能如何有助于在定义的海马回路中调节双向突触强度。