STRUCTURE, FUNCTION, AND MODULATION OF SERORTONIN (3A) RECEPTORS

项目总结/摘要 该提案的总体目标是确定变构机制的结构基础， 5-羟色胺受体（5-HT 3AR）的门控和调节。5-HT 3ARs在胃肠道疾病中起着至关重要的作用。 功能、疼痛传递和情绪障碍。5-HT 3AR抑制剂在临床上用于缓解恶心 和呕吐引起的癌症治疗，管理感染后腹泻和肠易激综合征， 治疗神经系统疾病，如双相情感障碍和抑郁症。合理的药物设计受到以下因素的限制 对5-HT 3AR和下游信号事件的结构-功能相关性的理解不足。我们 最近通过单粒子冷冻技术解决了静息构象中全长5-HT 3AR的结构， 电子显微镜（cryo-EM）。通过利用这种技术进步和进一步的生物化学 通过优化，我们的目的是确定潜在的5-HT 3AR门控和脂质调节的构象变化。 我们将通过多学科方法的组合来实现这些目标，包括冷冻EM，脉冲- EPR和电生理学。具体来说，我们将在多个实验中确定5-HT 3AR的高分辨率快照。 功能状态，在调制器结合构象，并在膜脂质成分的存在下。这些 结构将补充蛋白质动态研究在膜环境和广泛的 功能分析我们提出的工作预计将提供渠道的结构蓝图， 生理相关的构象和解开通道功能的分子机制。 这些研究将为更安全有效的靶向药物设计奠定基础。

Project Summary/Abstract The overarching goal of this proposal is to determine the structural basis for allosteric mechanisms governing gating and modulation in serotonin receptors (5-HT3AR). 5-HT3ARs play a crucial role in gastrointestinal functions, pain transmission, and mood disorders. Inhibitors of 5-HT3AR are in the clinical use to alleviate nausea and vomiting caused by cancer therapies, manage post-infection diarrhea and irritable bowel syndrome, and treat neurological conditions such as bipolar disorder and depression. Rational drug design has been limited by poor understanding of the structure-function correlations in 5-HT3AR and the downstream signaling events. We recently solved the structure of the full-length 5-HT3AR in the resting conformation by single-particle cryo- electron microscopy (cryo-EM). By capitalizing on this technical advancement and further biochemical optimization, we aim to determine the conformational changes underlying 5-HT3AR gating and lipid modulation. We will achieve these goals by a combination of multidisciplinary approaches that include cryo-EM, pulsed- EPR, and electrophysiology. Specifically, we will determine high-resolution snapshots of 5-HT3AR in multiple functional states, in modulator-bound conformations, and in the presence of membrane lipid constituents. These structures will be complemented with protein dynamic studies in a membrane environment and extensive functional analysis. Our proposed work is expected to provide structural blueprints of the channel in physiologically relevant conformations and unravel the molecular mechanisms underlying channel function. These studies will be foundational in the targeted drug design for safer and effective therapeutics.