Factors regulating Cav 2.1 modulation by Ca2+ in neurons

电压门控的钙离子通道将膜去极化与钙离子的内流结合起来，从而启动了广泛的 多种重要的生物学过程，包括磷酸化、基因转录和神经递质释放。 由于这些钙离子通道对细胞信号的重要性，它们的活性受制于多种形式的 监管。特别是，Cav2.1(P/Q型)钙离子通道经历了钙离子的双重反馈调节， 有助于某些突触的短期可塑性。在重复刺激中，Cav2.1钙电流最初增加 (促进)和逐渐减少(停用)。易化和失活都依赖于钙离子，因此可以 受控制神经元内钙离子水平的因素影响。本提案中提出的初步结果 表明在一些神经元中存在高浓度的钙缓冲蛋白，以及细胞内的钙离子 钙库可能是钙离子调节Cav2.1的重要决定因素。研究计划中概述的实验将 检验以下假设：这些因素对神经元Cav2.1通道的调制程度有重要影响 Ca2+。全细胞膜片钳电生理学、分子生物学和钙成像技术将用于 表征钙缓冲蛋白和细胞内钙存储如何通过以下方式影响Cav2.1的活性依赖反馈 转染组细胞和分离的神经细胞内均有钙离子。这项研究的发现可能会揭示新的机制 深入了解神经元中Cav2.1通道的异质性，并为替代方案提供新的见解 治疗与钙离子通道缺陷相关的疾病的策略，如密尔卡因。Eoileosv.和共济失调。

Voltage-gated Ca2+ channels couple membrane depolarization to the influx of Ca2+ into the cell, which initiates a wide variety of biologically important processes including phosphorylation, gene transcription and neurotransmitter release. Because of the importance of these Ca2+ channels for cellular signaling, their activity is subject to numerous forms of regulation. In particular, Cav2.1 (P/Q-type) Ca2+ channels undergo a dual feedback regulation by Ca2+ ions which contributes to short-term plasticity at some synapses. During repetitive stimuli, Cav2.1 Ca2+ currents initially increase (facilitate) and gradually decrease (inactivate). Both facilitation and inactivation are Ca2+-dependent and therefore can be influenced by factors controlling intracellular Ca2+ levels in neurons. Preliminary results presented in this proposal indicate that Ca2+ buffering proteins, which are present at high concentrations in some neurons, and Ca2+ in intracellular stores may be important determinantsof Cav2.1 regulation by Ca2+. The experiments outlined in the research plan will test the hypothesis that these factors critically influence the extent to which neuronal Cav2.1 channels are modulated by Ca2+. Whole-cell patch clamp electrophysiology, molecular biology, and Ca2+ imaging techniques will be used to characterize how Ca2* buffering proteins and intracellular Ca2+ stores affect activity-dependent feedback of Cav2.1 by Ca~+ both in transfected cells and isolated neurons. The findings from this research may reveal novel mechanisms underlying the heterogeneous properties of Cav2.1 channels in neurons and provide new insights into alternative strategies to treat diseases associated with Ca2+ channel defects, such as mieraine. eoileosv. and ataxia.