MODULATION OF ION CHANNELS BY PHOSPHOINOSITIDE METABOLISM

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 本项目涉及G蛋白偶联受体(GPCR)信号转导膜脂蛋白对离子通道功能的调节。它着重于一种假设，即许多离子通道的功能取决于质膜中一种稀有的磷脂--磷脂酰肌醇4，5-二磷酸(PIP2)的浓度。将测量从M1 M受体到磷脂酶C的信号步骤的动力学，以检验它们是快速的假设，可能反映了预先形成的信号复合体。将测量消耗和补充PIP2的代谢步骤的动力学，以了解PIP2的细胞来源和动力学。所有结果都将与一个全面的动力学模型相匹配，以提供有关信号级联机制的额外信息。我们将研究PIP2浓度变化和M胆碱信号对KCNQ通道和电压门控钙通道(Cav通道)功能的调节能力。这些方法将包括膜片钳电生理学、荧光共振能量转移、酶对细胞膜的动态靶向、共聚焦显微镜和化学分析。虚拟细胞建模和模拟软件将有助于对这些实验的分析和解释。大部分研究将在细胞系上进行。这项工作为理解荷尔蒙对精神状态的控制以及许多生物精神病学药物和滥用药物的作用奠定了基础。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project concerns the regulation of ion-channel function by G-protein-coupled receptor (GPCR) signaling to membrane lipids. It focuses on the hypothesis that the function of many ion channels depends on the concentration of one rare phospholipid, phosphatidylinositol 4,5-bisphosphate (PIP2) in the plasma membrane. The kinetics of signaling steps from M1 muscarinic receptors to phospholipase C will be measured to test the hypothesis that they are fast, perhaps reflecting a preformed signaling complex. The kinetics of the metabolic steps that deplete and replenish PIP2 will be measured to understand the cellular sources and dynamics of PIP2. All results will be fitted with a comprehensive kinetic model to provide additional information on the mechanisms of the signaling cascade. The ability of PIP2 concentration changes and muscarinic signaling to modulate function of KCNQ channels and voltage-gated Ca2+ channels (CaV channels) will be studied. The methods will include patch-clamp electrophysiology, fluorescence resonance energy transfer, dynamic targeting of enzymes to cellular membranes, confocal microscopy, and chemical analysis. Analysis and interpretation of these experiments will be facilitated with the Virtual Cell modeling and simulation software. Most of the studies will be done on cell lines. This work lays the basis for understanding hormonal control of mental state and the actions of many drugs of biological psychiatry and of drugs of abuse.