Regulation of ubiquitin ligase Nedd4-2 and cardiac sodium and potassium ion channels

泛素连接酶 Nedd4-2 和心脏钠钾离子通道的调节

• 批准号: 384368-2013
• 负责人: Zhang, Shetuan
• 金额: $ 2.19万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=629617
• 关键词: Regulation; ubiquitin; ligase; Nedd4; cardiac

BACKGROUND: Ion channels are membrane proteins which generate electrical signals essential for cell communication. They control many vital physiological processes such as brain function and muscle contractions. The number of channels in the plasma membrane is a key determinant for the amplitude of electrical signals. The channel numbers are tightly regulated by the creation and destruction. Recent work by us and others have shown that a molecule called Nedd4-2 (neural precursor cell expressed, developmentally down-regulated 4-2) mediates the degradation of several ion channels. Presently, it is not known how the activity of Nedd4-2 is regulated. Given its pivotal role, it is therefore critical to understand the regulation of Nedd4-2 function, which further determines the number of ion channels in the cell membrane.HYPOTHESIS: Activity of Nedd4-2 is regulated by intracellular Ca2+ levels, GTPase Rab4, and glucocorticoid-inducible kinase (SGK), which in turn regulates sodium and potassium channel expressions.OBJECTIVE: Using electrophysiology, cell biology and cell imaging techniques in cell line systems and rat cardiomyocytes, we will determine (1) the effect of intracellular Ca2+ on the function of Nedd4-2; (2) the effects of the small GTPase Rab4 on the Nedd4-2 activity; (3) the effects of SGK activation on the Nedd4-2 activity. We will further investigate the effects of altered Nedd4-2 on the function and expression of cardiac ion channels (e.g. Nav1.5, KCNQ1 and hERG) and the electrical properties of cardiac myocytes.SIGNIFICANCE: Information obtained from the present project focusing on ion channels will not only extend our understanding of human biology but also is essential for developing biotech products such as artificial pacemakers, and muscle prostheses. HQP involved will attain critical thinking skills and expertise in molecular biology and electrophysiology. They will become invaluable resources for education, biotech companies, and research laboratories. Such training will enhance Canada's Workforce Skills and will benefit Canadian economy.

背景：离子通道是产生细胞通讯所必需的电信号的膜蛋白。它们控制着许多重要的生理过程，如大脑功能和肌肉收缩。质膜中通道的数量是电信号幅度的关键决定因素。频道号受到创建和销毁的严格控制。我们和其他人最近的工作表明，一种名为Nedd4-2(神经前体细胞表达，发育下调的4-2)的分子介导了几种离子通道的降解。目前，Nedd4-2的活性是如何被调节的还不清楚。因此，了解Nedd4-2功能的调节是至关重要的，它进一步决定了细胞膜上的离子通道的数量。背景：Nedd4-2的活性受细胞内钙水平、GTPase Rab4和糖皮质激素诱导的激酶(SGK)的调节，后者反过来调节钠和钾通道的表达。目的：利用细胞系和大鼠心肌细胞的电生理学、细胞生物学和细胞成像技术，我们将确定(1)细胞内钙离子对Nedd4-2功能的影响；(2)小GTPase Rab4对Ned4-2活性的影响；(3)SGK激活对Nedd4-2活性的影响。我们将进一步研究改变的Nedd4-2对心脏离子通道(如NaV1.5、KCNQ1和HERG)的功能和表达以及心肌细胞的电学性质的影响。意义：从这个专注于离子通道的项目中获得的信息不仅将扩大我们对人类生物学的理解，而且对于开发人工起搏器和肌肉假体等生物技术产品也是必不可少的。所参与的HQP将获得批判性思维技能和分子生物学和电生理学方面的专业知识。它们将成为教育、生物技术公司和研究实验室的宝贵资源。这样的培训将提高加拿大的劳动力技能，并将使加拿大经济受益。