Mechanistic insights into homeostatic copper acquistion

说明(申请人提供)：铜是一种必需的，但有毒的微量营养素。铜是对正常生长和发育至关重要的酶的辅因子。铜代谢的遗传性疾病、与铜有关的退行性疾病以及各种生物中的营养性铜缺乏提供了惊人的证据，表明铜的稳态代谢是一个必不可少的生理过程。在这些临床相关性的背景下，铜运输系统的特征代表了一个重要的生物医学问题。Ctrl是真核生物中高度保守的整合膜蛋白家族，已被鉴定。虽然Ctrl在铜代谢中的作用刚刚开始被阐明，但对铜的最佳获取至关重要的Ctrl的作用机制和调控仍有待确定。Ctrl和其他参与铜代谢的成分之间的物理和功能相互作用尚不完全清楚。这项提议的长期目标是了解铜在质膜上的动态平衡运输的分子机制，并描述生物获得最佳铜水平的途径。本研究旨在阐明Ctrl铜转运蛋白的作用机制和调控机制。我们的初步数据显示，Ctrl的结构、表达水平、亚细胞定位和活性都以一种铜依赖的方式受到精细控制。我们的中心假设是，Ctrl翻译后的几层调控维持了细胞内铜的最佳获取。结合生理学、生物化学、细胞生物学和遗传学的多学科方法将被用来追求以下具体目标：1)我们将表征Ctrl多聚体复合体中与铜运输相耦合的分子事件。2)我们将阐明Ctrl氨基末端结构域在铜转运中的作用。3)我们将确定铜诱导的红牛敏感的Ctrl多聚体的生理意义、结构决定因素和信号转导。鉴于铜的获得是铜代谢的中心步骤，确定Ctrl的功能、作用模式和调节可能有助于更好地了解铜的动态平衡。考虑到威尔逊病、门克斯病、阿尔茨海默病和其他严重的退行性疾病与铜稳态的缺陷有关，对铜获得的分子机制的研究将最终提高我们对抗铜相关病理的能力。

DESCRIPTION (provided by applicant): Copper is an essential, yet toxic, micronutrient. Copper serves as a cofactor of enzymes that are vital for normal growth and development. Genetic disorders in copper metabolism, copper-implicated degenerative diseases, and nutritional copper deficiency in various organisms provide striking evidence that homeostatic copper metabolism is an essential physiological process. In the context of these clinical correlations, characterization of the copper transport system represents an important biomedical problem. Ctrl, a highly conserved family of integral membrane protein in eukaryotes, has been identified. While roles of Ctrl in copper metabolism have just begun to be elucidated, the mechanisms of action and regulation of Ctrl which is critical for optimal copper acquisition remain to be determined. Physical and functional interactions between Ctrl and other components involved in copper metabolism are not fully understood. The long-term goals of this proposal are to understand the molecular mechanisms of homeostatic copper transport across the plasma membrane and characterization of the pathways whereby organisms acquire optimal levels of copper. This application focuses on elucidation of the mechanisms of action and regulation of Ctrl copper transporter. Our preliminary data show that the structure, expression levels, subcellular localization and activity of Ctrl are delicately controlled in a copper-dependent manner. Our central hypothesis is that several layers of post-translational regulation of Ctrl maintain optimal cellular copper acquisition. A multi- disciplinary approach combining physiology, biochemistry, cell biology, and genetics will be employed to pursue the following specific aims: 1) We will charaterize molecuar events in the Ctrl multimeric complex that are coupled with copper transport. 2) We will elucidate the roles of the Ctrl amino terminal domain in copper transport. 3) We will define the physiological significance, structural determinants, and signaling involved in copper-induced red ox-sensitive multimerization of Ctrl. Given that Cu acquisition is a central step in Cu metabolism, defining the function, mode of action and regulation of Ctrl could lead to better insights into Cu homeostasis. Considering the fact that Wilson disease, Menkes disease, Alzheimer's disease, and other severe degenerative disorders are linked to defects in copper homeostasis, studies on the molecular mechanisms of copper acquisition would ultimately advance our ability to combat copper-related pathologies.