Mechanisms of Endosome Trafficking in Neurons

神经元内体运输的机制

• 批准号: 6606262
• 负责人: Victor Faundez
• 金额: $ 28.88万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6606262
• 关键词: PC12 cells; enzyme substrate; guanosinetriphosphatases; mass spectrometry; membrane fusion; membrane transport proteins; molecular cloning; neurons; phosphorylation; protein kinase; protein protein interaction; protein structure function; protein transport; radionuclides; synaptic vesicles; synaptogenesis; transfection

DESCRIPTION (provided by applicant): A central question to the biology of any cell, is how membrane proteins are specifically sorted by vesicle carriers. This problem is particularly pertinent to the synapse, a neuronal domain specialized in the trafficking of synaptic vesicles (SV). However, the mechansisms by which synaptic vesicle proteins make their sorting decisions are not well understood. To study this fundamental problem I have developed an adaptor-dependent neuronal vesiculation model. This mechanism is capable to sort from endosomes SV proteins using the adaptor complex AP-3 and two enzymes, a GTPase and an AP-3-associated kinase that phosphorylates the adaptor AP-3. Although phosphorylation has been recognized as an important cell regulatory mechanism, its role in adaptor function is mostly unexplored. The central hypothesis guiding this proposal is that an AP-3-associated kinase selectively regulates AP-3-dependent vesiculation and sorting functions. Our goal is to use unique cell-free reconstitution assays plus the analysis of synaptic vesicle protein trafficking in intact neurons to understand the basic mechanisms that govern SV protein sorting and to test the role of phosphorylation in controlling adaptor-dependent vesicle formation. These studies will reveal the first detailed model for the role of phosphorylation in an adaptor-dependent vesiculation process. In this proposal, we will convey the wealth of molecules, mechanisms and drugs that we have characterized in PC12 cells to dissect a novel endosome SV biogenetic pathway in neurons. In mice ablation of the AP-3 pathway results in pigment dilution, epilepsy, behavioral phenotypes and defective SV protein sorting whereas in humans generates the Hermansky-Pudlak II syndrome. The understanding of the AP-3 mechanisms and regulation will open avenues for the development of pathway-specific pharmacological agents that will impact the treatment of epilepsy, behavioral disorders and the Hermansky-Pudlak II syndrome.

描述（由申请人提供）： 任何细胞生物学的一个核心问题是膜蛋白如何通过囊泡载体专门分类。这个问题与突触尤其相关，突触是一种专门用于贩运突触囊泡（SV）的神经元结构域。但是，突触囊泡蛋白使其排序决策的机甲主义尚不清楚。为了研究这个基本问题，我开发了一个依赖适应器的神经元囊泡模型。该机制能够使用适配器复合物AP-3和两种酶，GTPase和AP-3相关激酶从内体SV蛋白排序，从而磷酸化衔接子AP-3。尽管磷酸化已被认为是重要的细胞调节机制，但其在衔接函数中的作用大多未开发。指导该建议的中心假设是AP-3相关激酶选择性调节AP-3依赖性囊泡和分类功能。我们的目标是使用独特的无细胞重建测定法加上完整神经元中突触囊泡蛋白运输的分析，以了解控制SV蛋白分类的基本机制，并测试磷酸化在控制适应体依赖性囊泡形成中的作用。这些研究将揭示磷酸化在适应器依赖性囊泡过程中的作用的第一个详细模型。在此提案中，我们将传达我们在PC12细胞中表征的分子，机制和药物的丰富，以剖析神经元中新型内体SV生物遗传途径。在ap-3途径的小鼠消融中，会导致色素稀释，癫痫，行为表型和有缺陷的SV蛋白排序，而人类中的人类产生了Hermansky-Pudlak II综合征。对AP-3机制和调节的理解将为发展途径特异性药理学剂的发展开放，这些途径将影响癫痫，行为障碍和Hermansky-Pudlak II综合征的治疗。