Lipid Modulation of Ligand-Gated Ion Channels

项目概要/摘要 五聚体配体门控离子通道（pLGIC）介导突触传递，并且是许多神经递质的靶点。 神经活性药物，其是pLGIC活性的变构调节剂。内源性脂质包括磷脂， 脂肪酸和类固醇也是pLGIC的变构调节剂，这些脂质的作用是基本的 我们对pLGIC生物学和调控的理解。本项目的长期目标是了解 脂质调节pLGIC的分子机制。我们开发了创新的生物物理和 生物化学技术检测pLGIC模型中脂质结合和调节，欧文氏菌 配体门控离子通道（ELIC），包括天然离子迁移率质谱（MS），功能分析， 模型膜和共价修饰/光标记。使用这些技术，我们发现， 阴离子磷脂，1-棕榈酰-2-油酰-磷脂酰甘油（POPG），直接与ELIC结合并调节 通过相对于不敏感状态稳定开路来进行通道选通。我们现在建议调查 两种模型pLGIC ELIC和GLIC的磷脂、脂肪酸和类固醇调节机制 （粘多糖配体门控离子通道），重点是阐明相互作用的特异性和位点，以及 脂质结合的影响。本研究计划的总体设想是开发一个详细的结构模型 pLGIC的脂质调节，包括在不同的细胞中存在的机制的潜在多样性， pLGIC。

Project Summary/Abstract Pentameric ligand-gated ion channels (pLGICs) mediate synaptic transmission and are the targets of many neuroactive drugs, which are allosteric modulators of pLGIC activity. Endogenous lipids including phospholipids, fatty acids and steroids are also allosteric modulators of pLGICs, and the effects of these lipids are fundamental to our understanding of pLGIC biology and regulation. The long-term goal of this project is to understand the molecular mechanisms by which lipids modulate pLGICs. We have developed innovative biophysical and biochemical techniques to examine lipid binding and modulation in the model pLGIC, Erwinia chrysanthemi ligand-gated ion channel (ELIC), including native ion mobility mass spectrometry (MS), functional analysis in model membranes, and covalent modification/photolabeling. Using these techniques, we discovered that the anionic phospholipid, 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG), directly binds to ELIC and modulates channel gating by stabilizing the open relative to the desensitized state. We now propose to investigate the mechanisms of phospholipid, fatty acid and steroid modulation of two model pLGICs, ELIC and GLIC (Gloeobacter ligand-gated ion channel), with a focus on elucidating the specificity and sites of interaction, and the effects of lipid binding. The overall vision of this research program is to develop a detailed structural model of lipid modulation of pLGICs that encompasses the potential diversity of mechanisms present in different pLGICs.