Metal Homeostatic Mechanisms in Yeast

酵母中的金属稳态机制

• 批准号: 6998438
• 负责人: Dennis R. Winge
• 金额: $ 23.38万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-12-15 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6998438
• 关键词: Metal; Homeostatic; Mechanisms; Yeast

DESCRIPTION (provided by applicant): This application focuses on homeostatic coupling of intracellular copper (Cu) and iron (Fe) levels to gene expression in the yeast Saccharomyces cerevisiae. Metalloregulation of Cu uptake genes is controlled by the Mac1 transcriptional activator. Metalloregulation of Fe uptake genes is controlled by two related activators, Aft1 and Aft2. These three factors are transcriptional activators in metal-deficient cells, but specifically inhibited in metal-replete cells. The major objectives are to elucidate the mechanisms of Cu ion sensing by Mac1 and Fe ion sensing by Aft1 and Aft2. Many interconnections exist between Fe and Cu homeostasis in yeast. In the past grant cycle we provided evidence suggestive that Mac1 senses Cu ions within the yeast nucleus through direct binding of Cu(I) ions by Mac1. Cu(I) binding appears to induce an intramolecular interaction between the N-terminal DNA binding domain and C-terminal transactivation domain. Studies are proposed to verify direct sensing of Cu and to map the intramolecular interface that inhibits both DNA binding and transactivation. An important goal is to identify other yeast proteins important in either Cu shuttling to the nucleus or Cu inhibition of Mac1. Fe-homeostasis in yeast is regulated by Aft1 and Aft2. The mechanism of Fe inhibition of Aft1 and Aft2 function is unknown. The significance of these studies is that S. cerevisiae is the best model eukaryotic system to understand the mechanism of Fe sensing by a transcription regulator. We propose to determine whether Fe sensing occurs through direct Fe binding, Fe-mediated post-translational modification or through another protein? Aft1 and Aft2 exhibit limited functional redundancy in yeast. We propose to determine whether each exhibits a distinct physiological function. Mac1 and Aftl/Aft2 are excellent model eukaryotic systems to study nutritional control of gone expression. Information gleaned on the mechanism of Cu- and Fe-regulation may be applicable to other species.

描述（由申请人提供）：本申请重点关注酿酒酵母中细胞内铜（Cu）和铁（Fe）水平与基因表达的稳态耦合。 Cu 摄取基因的金属调节由 Mac1 转录激活因子控制。 Fe 吸收基因的金属调节由两个相关的激活剂 Aft1 和 Aft2 控制。这三个因子在金属缺乏的细胞中是转录激活剂，但在金属充足的细胞中受到特别抑制。 主要目标是阐明 Mac1 感应 Cu 离子以及 Aft1 和 Aft2 感应 Fe 离子的机制。 酵母中 Fe 和 Cu 稳态之间存在许多相互联系。在过去的资助周期中，我们提供的证据表明 Mac1 通过 Mac1 直接结合 Cu(I) 离子来感知酵母细胞核内的 Cu 离子。 Cu(I) 结合似乎会诱导 N 端 DNA 结合结构域和 C 端反式激活结构域之间的分子内相互作用。建议进行研究以验证 Cu 的直接传感并绘制抑制 DNA 结合和反式激活的分子内界面。 一个重要的目标是鉴定在 Cu 穿梭至细胞核或 Cu 对 Mac1 的抑制中起重要作用的其他酵母蛋白。 酵母中的 Fe 稳态由 Aft1 和 Aft2 调节。 Fe 抑制 Aft1 和 Aft2 功能的机制尚不清楚。 这些研究的意义在于，酿酒酵母是了解转录调节因子对 Fe 的感应机制的最佳真核系统模型。 我们建议确定 Fe 传感是通过直接 Fe 结合、Fe 介导的翻译后修饰还是通过另一种蛋白质发生？ Aft1 和 Aft2 在酵母中表现出有限的功能冗余。 我们建议确定每种物质是否表现出独特的生理功能。 Mac1 和 Aftl/Aft2 是研究消失表达的营养控制的优秀模型真核系统。 收集到的有关铜和铁调节机制的信息可能适用于其他物种。