Regulation of parallel recycling pathways at synaptic sites

突触位点平行回收途径的调节

• 批准号: 10665064
• 负责人: Michael Mark Alexander Sutton
• 金额: $ 49.25万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-15 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10665064
• 关键词: Address; Brain; Complex; Data; Defect; Dendritic Spines; Dorsal; Down-Regulation; Endosomes; Excitatory Synapse; Frequencies; Glutamate Receptor; Hippocampus; Immunofluorescence Microscopy; Inhibitory Synapse; Integrins; Lentivirus; Lipids; Long-Term Depression; Maintenance; Measures; Membrane; Minor; Molecular; Mutation; Nervous System; Neuroglia; Neurons; PI3 gene; Pathway interactions; Phosphatidylinositols; Play; Proteins; Proteomics; Publishing; Rattus; Recruitment Activity; Recycling; Regulation; Role; Signal Transduction; Site; Slice; Surface; Synapses; Synaptic plasticity; Testing; Vertebral column; density; genetic regulatory protein; inorganic phosphate; insight; knock-down; nervous system disorder; phosphatidylinositol 5-phosphate; postsynaptic; protein function; protein protein interaction; receptor; receptor recycling; recruit; small hairpin RNA; synaptic function; trafficking

PROJECT SUMMARY/ABSTRACT Phosphoinositide signaling lipids are key regulators of endomembrane trafficking and are critical for synaptic function and plasticity. Notably, many synapse-specific trafficking pathways are highly similar to cognate pathways in non-neuronal cells. The specialized trafficking at synapses is largely achieved via modest alterations to generic trafficking pathways. Due to the high demand of traffic at synapses, very minor mutations in these pathways specifically impact the nervous system and underlie a wide range of neurological disorders. PIKfyve and its regulatory proteins Vac14 and Fig4 control the cellular levels of the low abundance signaling lipids phosphatidylinositol (3,5)-bis phosphate (PI3,5P2) and phosphatidylinositol 5- phosphate (PI5P). Studies from us and others revealed that minor mutations in this pathway are associated with several neurological disorders. Insights into roles of PI(3,5)P2 in neurons came from our discovery that PIKfyve plays essential roles in synaptic function and plasticity, and acts in part via controlling the surface levels of AMPA- type glutamate receptors (AMPARs). PIKfyve downregulation results in enhanced recycling and surface levels of AMPAR, although the underlying molecular mechanism(s) are unknown. Paradoxically, our new studies in non-neuronal cells, reveal that PIKfyve has a direct positive role in the control of the SNX17 recycling pathway. Notably, both the SNX17 and SNX27 pathways emerge from the same microdomains on endosomes. This places PIKfyve on endosomes that actively recycle both SNX17-dependent and SNX27-dependent cargoes. Importantly AMPAR surface levels are controlled in part via SNX27-dependent recycling. Aim 1 of this proposal seeks to determine whether PIKfyve controls AMPAR surface levels via negative regulation of SNX27- dependent recycling. Importantly, our new studies raise the possibility that dysregulation of SNX17 during PIKfyve inhibition, may also contribute to the observed synaptic defects. Mutations in proteins that function with SNX17 underlie some neurological diseases, but surprisingly, there are no published studies to establish whether SNX17 recycling is critical for synaptic function. The current project will test the hypothesis that PIKfyve differentially regulates distinct recycling pathways that emerge from the same endosomes. To address this hypothesis we will 1) Determine mechanisms whereby PIKfyve regulates AMPAR recycling; 2) Determine roles of the SNX17- Retriever pathway in neurons and whether similar to non-neuronal cells, PIKfyve is a regulator of this pathway.

项目摘要/摘要 磷酸肌醇信号传导脂质是内膜运输的关键调节剂，对于突触至关重要 功能和可塑性。值得注意的是，许多突触特异性的贩运途径与同类高度相似 非神经元细胞中的途径。突触的专业贩运在很大程度上是通过谦虚实现的 对通用贩运途径的改变。由于突触的交通需求量很大，突变非常小 在这些途径中，特别影响了神经系统，并构成了广泛的神经系统疾病。 Pikfyve及其调节蛋白vac14和Fig4控制低丰度的细胞水平 信号脂质磷脂酰肌醇（3,5） - 磷酸盐（PI3,5P2）和磷脂酰肌醇5-磷酸盐 （PI5P）。来自我们和其他人的研究表明，该途径中的小突变与几种相关 神经系统疾病。对神经元中Pi（3,5）P2角色的见解来自我们发现Pikfyve扮演的角色 在突触功能和可塑性中的重要作用，并部分通过控制AMPA-的表面水平起作用 型谷氨酸受体（AMPAR）。 pikfyve下调导致回收和表面水平增强 尽管基本的分子机制尚不清楚，但AMPAR的矛盾的是，我们在 非神经元细胞表明，Pikfyve在控制SNX17回收途径中具有直接的积极作用。 值得注意的是，SNX17和SNX27途径均来自内体的同一微区域出现。这 将Pikfyve放置在积极回收SNX17依赖性和SNX27依赖性货物的内体上。 重要的是，AMPAR表面水平由SNX27依赖性回收部分控制。目的1本提案 试图确定Pikfyve是否通过SNX27-的负调控来控制AMPAR表面水平 依赖回收。 重要的是，我们的新研究提出了pikfyve抑制期间SNX17失调的可能性， 也可能有助于观察到的突触缺陷。 SNX17基础功能的蛋白质突变 一些神经系统疾病，但令人惊讶的是，尚无公开研究来确定SNX17是否存在 回收对于突触功能至关重要。当前项目将检验pikfyve差异化的假设 调节从同一内体出现的不同的回收途径。为了解决这一假设 将1）确定Pikfyve调节AMPAR回收的机制； 2）确定SNX17-的作用 pikfyve是该途径的调节剂。