REGULATION OF ION CHANNELS IN NERVE CELLS

我建议继续我们正在进行的关于神经元离子调节的研究， 渠道 离子通道特性的调节是离子通道的基础。 神经元电活动的长期调节的重要性。 我们的方法仍然是一个还原论，并涉及使用组合 生物化学、分子、生物物理和生理技术来研究 信道调制 在下一个拨款期内，我们会集中研究 大鼠两类离子依赖性钾通道的调节 脑：钙依赖性钾（KCa）通道和钠依赖性 钾（KNa）通道。 (1)We广泛研究了脑细胞膜上KCa通道的调节 补丁和磷脂双层，并已获得证据， 内源性蛋白激酶和磷酸酶活性， 与这些通道中的一些相关并调节它们的活动。 我们将扩展这些研究，以表征内源性激酶， 磷酸酶活性的详细信息，目的是了解他们如何 相互作用以调节KCa通道活性。 这将涉及使用 药理学探针，结合单通道测量。 (2)We已经证明KNa通道广泛存在于哺乳动物的大脑中 并且也经受调制。 它们的活动迅速减少 分离的膜补丁，但不在细胞附着的补丁中，这表明 某些胞质因子是维持KNa通道所必需的 活动 我们将研究KNa通道调节的机制， 将它们与KCa通道调节中涉及的机制进行比较。 (3)We将利用我们最近的惊人发现， 对应于Shaker样钾的氨基末端区域 KCa和KNa通道也可以相互作用并阻断大脑KCa和KNa通道。 我们将对这些相互作用进行详细的生物物理研究， 目的是确定可能是共同的结构特征之间的 振荡器样和离子依赖性钾通道。 我对此感到兴奋 获得渠道监管机制新见解的独特机会 通过比较两种不同类型的离子的性质和调制， 依赖性钾通道

I propose to continue our ongoing studies on the regulation of neuronal ion channels. Modulation of ion channel properties is of fundamental importance for the long-term regulation of neuronal electrical activity. Our approach remains a reductionist one, and involves the use of combined biochemical, molecular, biophysical and physiological techniques to study channel modulation. We will focus during the next funding period on the modulation of two classes of ion-dependent potassium channels from rat brain: calcium-dependent potassium (KCa) channels and sodium-dependent potassium (KNa) channels. (1)We have studied modulation of brain KCa channels extensively in membrane patches and phospholipid bilayers, and have obtained evidence for endogenous protein kinase and phosphatase activities that are closely associated with some of these channels and that modulate their activity. We will extend these studies to characterize the endogenous kinase and phosphatase activities in detail, with the goal of understanding how they interact to regulate KCa channel activity. This will involve the use of pharmacological probes, in conjunction with single channel measurements. (2)We have demonstrated that KNa channels are widespread in mammalian brain and are also subject to modulation. Their activity runs down rapidly in detached membrane patches but not in cell-attached patches, indicating that some cytoplasmic factor(s) is necessary for the maintenance of KNa channel activity. We will study the mechanisms of KNa channel modulation, and compare them with mechanisms involved in KCa channel modulation. (3)We will exploit our recent surprising finding that a peptide corresponding to the amino-terminal region of Shaker-like potassium channels can interact with and block brain KCa and KNa channels as well. We will carry out a detailed biophysical study of these interactions, with the goal of identifying structural features that may be common between the Shaker-like and the ion-dependent potassium channels. I am excited by this unique opportunity to gain new insights into channel regulatory mechanisms by comparing the properties and modulation of two distinct classes of ion- dependent potassium channels.