An adaptor protein for dendritic spine exocytosis and postsynaptic plasticity

用于树突棘胞吐作用和突触后可塑性的接头蛋白

• 批准号: 8263917
• 负责人: Angela M Mabb
• 金额: $ 2.29万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8263917
• 关键词: adaptor; protein; dendritic; spine; exocytosis

DESCRIPTION (provided by applicant): The targeted delivery of AMPA-type glutamate receptors (AMPAR) from intracellular compartments to the postsynaptic membrane is a major cellular mechanism for learning-related synaptic plasticity in the mammalian brain. Yet, little is known about the molecular machinery that ensures the spine- specific transport of AMPARs to the synapse. Prior work in our laboratory has demonstrated that recycling endosomes (REs) within and at the base of spines provide membrane and AMPARs to the synapse when using a protocol for learning known as long term potentiation (LTP). Although it is established that activity- dependent recruitment of REs to dendritic spines is essential for the expression of LTP, the precise location of RE docking for the delivery of receptors and membrane in dendrites remains obscure. Here, we have identified regions of exocytosis in dendritic spines that are positioned adjacent to the postsynaptic density. Further, we describe a putative molecular sensor, the adaptor molecule Rabi 1-FIP2 which aids in the correct membrane positioning of REs for proper spine exocytosis. This proposal will aim to (1) identify the signaling pathways required for Rabi 1-FIP2 spine localization (2) determine if disruption of Rabi 1-FIP2 mediates spine exocytosis and (3) define the functional consequences of Rabi 1-FIP2 disruption on facilitating delivery of AMPA receptors to spine membranes for the expression of LTP. Experiments will use a combination of basic biochemical approaches and live cell imaging in hippocampal neurons to identify the critical signaling pathways and requirement of Rabi 1-FIP2 for spine exocytosis. Further, organotypic hippocampal slices in combination with electrophysiology will be used to test the function of Rabi 1-FIP2 on LTP. Since exocytosis from REs is crucial for the proper deliver of AMPARs to the postsynaptic membrane, we propose that this Rabi 1-FIP2 dependent cellular mechanism is a key element for learning-related synaptic plasticity in the mammalian brain. Public information: The delivery of AMPA receptors (AMPARs) from intracellular compartments known as recycling endosomes to the postsynaptic membrane of synapses is a major cellular mechanism for learning- related synaptic plasticity in the brain. In addition, dysregulation of endosomal function and AMPAR trafficking in dendritic spines contributes to various neurological disorders such as Alzheimer's disease, Down's syndrome, and schizophrenia. This proposal will focus on identifying the molecular machinery that is critical for learning-related synaptic plasticity in the mammalian brain and will provide insight into how disruption of endosomal function leads to neurological disease.

描述（由申请人提供）：AMPA型谷氨酸受体（AMPAR）从细胞内隔室靶向递送至突触后膜是哺乳动物大脑中学习相关突触可塑性的主要细胞机制。然而，人们对确保AMPAR向突触的脊柱特异性运输的分子机制知之甚少。我们实验室先前的工作已经证明，当使用称为长时程增强（LTP）的学习协议时，在棘内和棘基部的再循环内体（RE）为突触提供膜和AMPAR。虽然已经确定RE向树突棘的活性依赖性募集对于LTP的表达是必不可少的，但是用于递送受体和树突中的膜的RE对接的精确位置仍然不清楚。在这里，我们已经确定了位于突触后致密物附近的树突棘中的胞吐区域。此外，我们描述了一个假定的分子传感器，适配器分子Rabi 1-FIP 2，它有助于正确的膜定位的RE适当的脊柱胞吐。该提案旨在（1）鉴定Rabi 1-FIP 2棘定位所需的信号传导途径（2）确定Rabi 1-FIP 2的破坏是否介导棘胞吐作用和（3）确定Rabi 1-FIP 2破坏对促进AMPA受体递送至棘膜以表达LTP的功能后果。实验将使用基本的生物化学方法和海马神经元中的活细胞成像的组合来鉴定Rabi 1-FIP 2对于棘胞吐的关键信号通路和要求。此外，将使用与电生理学组合的器官型海马切片来测试Rabi 1-FIP 2对LTP的功能。由于RE的胞吐作用对于AMPAR正确传递到突触后膜是至关重要的，因此我们提出这种Rabi 1-FIP 2依赖性细胞机制是哺乳动物大脑中学习相关突触可塑性的关键因素。公共信息：AMPA受体（AMPAR）从称为再循环内体的细胞内区室递送到突触的突触后膜是脑中学习相关的突触可塑性的主要细胞机制。此外，树突棘中内体功能和AMPAR运输的失调有助于各种神经系统疾病，如阿尔茨海默病、唐氏综合征和精神分裂症。该提案将侧重于确定对哺乳动物大脑中与学习相关的突触可塑性至关重要的分子机制，并将深入了解内体功能的破坏如何导致神经系统疾病。