Cellular Mechanisms of Neuronal Metal Transport and Toxicity

神经元金属转运和毒性的细胞机制

• 批准号: 7086650
• 负责人: Victor Faundez
• 金额: $ 28.71万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7086650
• 关键词: cytotoxicity; intracellular transport; laboratory mouse; laboratory rat; metal metabolism; neuronal transport; protein localization; protein protein interaction; proteomics; synaptic vesicles; transport proteins; ubiquitin; vesicle /vacuole; zinc

DESCRIPTION (provided by applicant): Zinc plays fundamental and diverse roles in cells yet excess free zinc is associated with metal cytotoxicity. To balance these opposing effects, cells have evolved universal mechanisms controlling cytoplasmic metal concentration. Cells accomplish this goal by zinc extrusion into the extracellular space, chelation by cytosolic chaperones, or sequestration within intracellular compartments. This last mechanism is the less explored process and it constitutes the main focus of our proposal. Zinc plays fundamental roles in synaptic physiology as well as in acute and chronic pathological conditions, ranging from excitotoxicity to the formation of amyloid aggregates characteristic of neurodegenerative diseases. Despite these fundamental roles of zinc, our understanding of the contribution of intracellular compartment in metal sequestration and homoeostasis is limited. In neurons, organellar zinc is stored in synaptic vesicles (SVs) by the activity of a synaptic vesicle specific zinc transporter, ZnT3. We have isolated and characterized by proteomics a ZnT3- enriched vesicle population. In these vesicles, we have identified ~ 140 molecular targets, several of which either up- or down-regulate vesicular endosomal zinc stores. These molecules provide a unique set of tools to assess the role of intracellular organelles, en particular endosomes and SV, in normal and pathological metal homeostasis. Our studies suggest that ZnT3 transport function are regulated by the nature of the compartment in which the ZnT3 transporter resides. Consistent with this notion, we have identified three targeting mechanisms that control ZnT3 subcellular localization that have the potential to regulate ZnT3 zinc transport function. In this proposal, we will specifically explore these novel regulatory paradigms testing the hypothesis that endosome-specific zinc transporter interactions regulate zinc transporter activity and resistance to metal-induced cytotoxicity.

描述（由申请人提供）：锌在细胞中起基本和多样的作用，但过量的自由锌与金属细胞毒性有关。为了平衡这些相反的影响，细胞已经发展出控制细胞质金属浓度的通用机制。细胞通过将锌挤出到细胞外空间，通过胞质伴侣或细胞内室内的隔离来实现这一目标。最后一个机制是较少探索的过程，它构成了我们提案的主要重点。锌在突触生理以及急性和慢性病理状况中扮演着基本角色，从兴奋性毒性到形成神经退行性疾病的特征。尽管锌的这些基本作用，但我们对金属隔离和同性恋者中细胞内室的贡献的理解是有限的。在神经元中，细胞器锌通过突触囊泡特异性锌转运蛋白Znt3的活性存储在突触囊泡中（SVS）中。我们已经以蛋白质组学为Znt3-富含囊泡的囊泡分离和特征。在这些囊泡中，我们已经确定了〜140个分子靶标，其中一些靶标是向上或下调囊泡内体锌储备。这些分子提供了一组独特的工具，可以评估正常和病理金属稳态中细胞内细胞器，特定内体和SV的作用。我们的研究表明，Znt3传输函数受Znt3转运蛋白所在的隔室的性质调节。与这个概念一致，我们已经确定了控制Znt3亚细胞定位的三种靶向机制，这些机制具有调节Znt3锌传输函数的潜力。在此提案中，我们将专门探索这些新的调节范例，以测试内体特异性锌转运蛋白相互作用的假设调节锌转运蛋白的活性和对金属诱导的细胞毒性的抗性。