Lipid Reguation of Voltage-gated Sodium Channels

电压门控钠通道的脂质调节

• 批准号: 435649-2013
• 负责人: DAvanzo, Nazzareno
• 金额: $ 2.33万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=533270
• 关键词: Lipid; Reguation; Voltage; gated; Sodium

Voltage-gated sodium (Nav) channels, like all ion channels, are proteins that span across the lipid bilayer to allow for the conduction of ions from one side of a cellular membrane to the other. Thus, ion channels intimately interact with the lipids in which they are embedded. In recent years, we are now gaining appreciation for the complexity and dynamic nature of the lipid landscape, which vary both spatially and temporally within a cell, and that the physiochemical properties of the cell membrane (headgroup, degree of acyl tail unsaturation, hydrophobic thickness, curvature) may regulate the function of proteins through direct and indirect lipid-protein interactions. However, although the intimate interaction of ion channels with the membrane can be a major determinant of their function, lipid regulation of ion channels remains largely uncharacterized. This is because until recently, efforts to address lipid regulation of ion channels remained largely qualitative because of the inability to obtain purified channels and because these studies could be only performed in cells where lipid composition is complex, poorly understood and difficult to control. In view of my previous work with other ion channels, I hypothesize that Nav channels are regulated by the physiochemical properties of the membrane lipids in which they are embedded. Critical breakthroughs in purifying functional bacterial homologues of Nav channels have been recently made, enabling us to examine their lipid dependence by reconstituting purified bacterial Nav proteins into liposomes of defined composition. Combining this approach with other biophysical and structural techniques (lipid binding assays, flux assays, electrophysiological recordings, LRET, SAXS, and mass spectrometry) will enable us to expand our understanding of lipid regulation to a new class of channels, to uncover novel mechanisms of regulation in Nav channels and understand the underlying molecular basis for their lipid regulation. These data will allow us to uncover novel mechanisms of regulation in Nav channels that are otherwise unobtainable in cellular systems and provide insights into the convergent or divergent evolution of lipid regulation in voltage-gated ion channels.

电压门控钠（Nav）通道，像所有离子通道一样，是跨越脂质双层的蛋白质，允许离子从细胞膜的一侧传导到另一侧。 因此，离子通道与它们嵌入其中的脂质密切相互作用。近年来，我们现在越来越了解脂质景观的复杂性和动态性，它们在细胞内在空间和时间上都有变化，并且细胞膜的理化性质（头基、酰基尾部不饱和度、疏水性厚度、曲率）可以通过直接和间接的脂质-蛋白质相互作用调节蛋白质的功能。然而，尽管离子通道与膜的密切相互作用可能是其功能的主要决定因素，但离子通道的脂质调节在很大程度上仍未被表征。这是因为直到最近，解决离子通道的脂质调节的努力仍然主要是定性的，因为无法获得纯化的通道，并且因为这些研究只能在脂质组成复杂、了解不多和难以控制的细胞中进行。鉴于我以前的工作与其他离子通道，我假设，Nav通道的调控膜脂质的理化性质，它们嵌入。最近在纯化Nav通道的功能性细菌同源物方面取得了重大突破，使我们能够通过将纯化的细菌Nav蛋白重组到确定组成的脂质体中来检查它们的脂质依赖性。将这种方法与其他生物物理和结构技术（脂质结合测定，通量测定，电生理记录，LRET，SAXS和质谱法）相结合，将使我们能够将我们对脂质调节的理解扩展到一类新的通道，揭示Nav通道的新调节机制，并了解其脂质调节的潜在分子基础。 这些数据将使我们能够发现在细胞系统中无法获得的Nav通道中的新的调节机制，并提供对电压门控离子通道中脂质调节的收敛或发散演变的见解。