Molecular Mechanism of Regulation of the Human Copper Transporter ATP7B

人铜转运蛋白 ATP7B 调控的分子机制

• 批准号: RGPIN-2017-06822
• 负责人: Dmitriev, Oleg
• 金额: $ 1.89万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=649383
• 关键词: Molecular; Mechanism; Regulation; Human; Copper

Copper is an essential cofactor in many biological processes, yet excess of copper is highly toxic for the cells, and acquisition, distribution and removal of copper from the human cells is tightly controlled. Copper transport processes in the cell are complex and not well understood at present. The long term goal of our research is to elucidate the molecular mechanism of copper transport in human tissues. The key enzymes in copper metabolism in the cell are two structurally similar ATP-driven membrane transporters, ATP7B, which is the focus of this research proposal, and ATP7A. Enzymatic activity and intracellular localization of ATP7B are regulated by copper. In the cell, copper, delivered by a chaperone protein Atox1, is transferred to the chain of six cytosolic metal binding domains (MBD1-6) of ATP7B. Conformation of MBD1-6, the subsequent steps of intramolecular copper transfer, and the mechanism of ATP7B regulation by copper are unknown. Our central hypothesis is that copper-dependent changes in the interactions and the three-dimensional fold of the MBD chain trigger relocalization of ATP7B from the trans-Golgi network to the cytosolic membrane vesicles and plasma membrane, and activate copper transport across the cell membranes and out of the cell. Using high-resolution NMR, small-angle X-ray scattering (SAXS) and biochemical methods, we will determine how the conformation and dynamics of MBD1-6 regulate activity and intracellular localization of MBD1-6. This work will provide new insight into the fundamental principles of biological regulation of multidomain eukaryotic proteins, and advance our knowledge of metal transport processes in the human cells.

铜是许多生物过程中必不可少的辅因子，但过量的铜对细胞具有高度毒性，铜的获取、分布和从人体细胞中的移除受到严格控制。铜在电池中的运输过程是复杂的，目前还没有很好的了解。我们研究的长期目标是阐明铜在人体组织中转运的分子机制。细胞内铜代谢的关键酶是两个结构相似的由ATP驱动的膜转运蛋白，ATP7B和ATP7A，这是本研究计划的重点。ATP7B的酶活性和细胞内定位受铜的调节。在细胞中，由伴侣蛋白Atox1传递的铜被转移到ATP7B的六个胞质金属结合结构域(MBD1-6)的链上。MBD1-6的构象、分子内铜转移的后续步骤以及铜对ATP7B的调控机制尚不清楚。我们的中心假设是，铜依赖的相互作用和MBD链三维折叠的变化触发了ATP7B从跨高尔基网络到细胞膜囊泡和质膜的重新定位，并激活了铜跨细胞膜和细胞外的运输。利用高分辨核磁共振、小角X射线散射(SAXS)和生化方法，我们将确定MBD1-6的构象和动力学如何调节MBD1-6的活性和细胞内定位。这项工作将为多结构域真核蛋白生物调控的基本原理提供新的见解，并促进我们对人类细胞中金属运输过程的了解。