Celllular mechanisms of neuronal metal transport and toxicity

描述（由申请人提供）：神经元锌参与关键过程，如兴奋性神经传递的调节。相反，神经元对过量的这种金属特别敏感。为了平衡这些相反的作用，细胞具有精细控制细胞质游离金属浓度的机制。在这些机制中，通过细胞器金属螯合的锌稳态依赖于ZnT/SLC 30锌转运蛋白家族成员。这些机制是本申请的重点。神经元中主要的ZnT/SLC 30锌转运体是ZnT 3。ZnT 3位于突触囊泡中，其遗传缺陷调节从癫痫到阿尔茨海默病的病理学。在我们之前的资助期间，我们发现ZnT 3的分布和锌转运活性受其低聚化的控制 状态ZnT 3二聚体通过ZnT 3间双酪氨酸键赋予细胞对锌毒性的抗性，所述ZnT 3间双酪氨酸键的产生由氧化还原机制催化。这是第一个由双酪氨酸键调控的膜蛋白的例子。我们建议，隔室特定的ZnT 3转运蛋白寡聚化通过氧化还原机制调节金属毒性抗性。在本申请中，我们使用ZnT 3中的二聚化获得和丧失功能突变以及在ZnT 3运输和转运途径中携带缺陷或获得功能的小鼠在体外和体内测试该假设。我们的研究将影响我们对锌发挥作用的急性和慢性神经系统疾病过程的理解和可能的治疗，如癫痫和阿尔茨海默病。

DESCRIPTION (provided by applicant): Neuronal zinc participates in key processes such as modulation of excitatory neurotransmission. In contrast, neurons are particularly susceptible to excess of this metal. To balance these opposing effects, cells possess mechanisms to finely control free cytoplasmic metal concentration. Among these mechanisms, zinc homeostasis by organelle metal sequestration relies on ZnT/SLC30 zinc transporter family members. These mechanisms are the focus of this application. The main ZnT/SLC30 zinc transporter in neurons is ZnT3. ZnT3 is located in synaptic vesicles and its genetic deficiency modulates pathology ranging from epilepsy to Alzheimer's disease. During our previous funding period, we discovered that ZnT3 distribution and zinc transport activity are controlled by its oligomerization state. ZnT3 dimers confer cellular resistance to zinc toxicity by an inter-ZnT3 dityrosine bond whose generation is catalyzed by redox mechanisms. This is the first example of a membrane protein regulated by dityrosine bonds. We propose that compartment-specific ZnT3 transporter oligomerization by redox mechanisms regulates metal toxicity resistance. In this application, we test this hypothesis in vitro and in vivo using dimerization gain- and loss-of-function mutations i ZnT3 as well as mice carrying deficiencies or gain-of-function in the ZnT3 trafficking and transport pathways. Our studies will impact our understanding and possibly treatment of acute and chronic neurological disease processes where zinc play a role such as epilepsy and Alzheimer's disease.