DYNAMIC REGULATION IN COPPER ION HOMEOSTASIS

描述(改编自申请者摘要)：人类和 威尔逊病是由一种金属离子的稳态缺陷引起的， 铜(Cu2+和Cu2+)。铜离子是一种动态的生物性质， 基本的但有毒的。这两种疾病代表了 铜离子动态平衡：铜离子缺乏和过剩。铜离子 铜离子依赖性酶铅缺乏导致功能丧失 与门克斯病有关。铜离子过量介导的毒性是威尔逊的 疾病。由于铜离子是一种基本的营养物质，但又是一种强效的 毒素，细胞必须拥有动态的动态平衡才能维持适当的 细胞水平的铜离子。其分子机制是什么？ 动态铜离子动态平衡？这仍然是一个根本性的问题 待解决的问题。这项提案的目标是，使用酵母作为模型 系统，研究铜离子动态平衡的动态调节。 酵母细胞执行与所需的类似的生化反应 在人类身上。此外，铜离子的动态平衡机制在很大程度上 在酵母、人类和其他不同物种中保守。 Mac1p是一种可能的金属离子敏感型酵母蛋白，其功能是关键 高亲和力铜离子吸收和转运的调节因子 生理条件。最近的研究表明，Mac1p 对铜离子的毒性水平做出反应 调节蛋白质降解的机制。Mac1p降级是一种新的 铜离子动态平衡的机制及其非调控机制 铜离子转运蛋白基因CTR1和CTR3表达的功能。这个 Mac1p在生理和毒性铜离子作用下的功能差异 条件反映了铜离子的动态生物学性质。 因此，了解Mac1p函数将有助于 确定铜离子动态平衡的分子机制。在这 建议，结合遗传学、分子生物学、化学和 生化方法被设计用来确定精确的分子 Mac1p的作用机制。这些方法将应用于 回答以下问题：(1)Mac1p如何回应 铜离子的生理和毒性水平有何不同？(2) Mac1p如何感知铜离子及其浓度变化？(3)什么 是调控蛋白的分子机制和重要性 铜离子动态平衡的降解？这些建议的结果 研究将为理解 动态铜离子动态平衡。

DESCRIPTION (adapted from applicant's abstract): Human Menkes and Wilsons diseases are caused by homeostatic defects of a metal ion, copper (Cu2+ and Cu+). Copper ion is a dynamic biological nature, essential yet toxic. The two diseases represent the two extremes in copper ion homeostasis: copper ions deficiency and excess. Copper ion deficiency caused loss of function of copper ion-dependent enzymes leads to Menkes disease. Copper ion excess mediated toxicity is Wilson's disease. Since the copper ion is an essential nutrient yet a potent toxin, cells must possess a dynamic homeostasis to maintain a proper cellular level of copper ions. What is the molecular mechanism of dynamic copper ion homeostasis? This is still a fundamental question to be addressed. The goal of this proposal is, using yeast as a model system, to study the dynamic regulation in copper ion homeostasis. Yeast cells carry out similar biochemical reactions to those required in humans. Furthermore, copper ion homeostatic mechanisms are largely conserved among yeast, human and other divergent species. Mac1p, a putative metal ion sensing yeast protein, functions as a key regulatory factor in high affinity copper ion uptake and transport under physiological conditions. Recent studies have demonstrated that Mac1p responds to toxic levels of copper ions through an uncharacterized mechanism of regulated protein degradation. Mac1p degradation is a new mechanism in copper ion homeostasis and independent of its regulatory function in copper ion transporter gene CTR1 and CTR3 expression. The differential functions of Mac1p under physiological and toxic copper ion conditions reflect the dynamic biological nature of copper ions. Therefore, understanding Mac1p functions will be instrumental to determine molecular mechanism of dynamic copper ion homeostasis. In this proposal, a combination of genetic, molecular biology, chemical and biochemical methods are designed to determine the precise molecular mechanisms of Mac1p functions. These approaches will be applied to address the following questions: (1) how does Mac1p respond differentially to physiological and toxic levels of copper ions? (2) how does Mac1p sense copper ion and its concentration changes? (3) What is the molecular mechanism and importance of regulated protein degradation in copper ion homeostasis? The outcomes of these proposed research will make fundamental contributions to the understanding of dynamic copper ion homeostasis.