Multi-scale observation and modeling of IP3/Ca signaling

描述（由申请人提供）： 细胞内储存到胞质溶胶中被用作信号传导机制， 几乎所有的细胞类型都能调节分泌等多种功能， 收缩、增殖和细胞死亡。观测的进展 技术揭示了细胞内Ca 2+的复杂模式， 选择性调节特定的细胞反应，并构建 通过单个离子通道的活性分级地， 集群内的通道和集群之间的交互。不可能 在一个实验中同时解决所有这些尺度， 较短的时间和距离尺度不能通过任何可用的 实验方法。因此，我们建议使用一个紧密集成的 建模、电生理学和高分辨率细胞钙的方法 成像，以阐明“基本”Ca 2+事件的机制， 触发并耦合以产生全局细胞钙信号。 具体的目的是描述（i）动力学机制的钙通量 通过单一渠道，（ii）个人之间的功能耦合 集群内的通道，以及（iii）集群之间的协调， 全局信号的传播以及缓冲区对该过程的影响。 将根据假设和参数值构建数值模型 来自膜片钳和共聚焦细胞成像实验，并将 通过与观测值的比较以及它们的预测 动力.我们的总体目标是开发一个全面的细胞内 Ca 2+信号与大量观察结果一致， 预测价值，并延伸到关键的-但实验无法达到 - 空间和时间尺度（纳米和微秒）。我们将重点介绍肌醇 三磷酸盐介导的Ca 2+信号转导，利用非洲爪蟾卵母细胞作为一个 很好的特征模型系统，但紧急原则将广泛 适用于许多细胞类型和物种，以及钙信号传导 由ryanodine受体介导。

DESCRIPTION (provided by applicant): The liberation of calcium ions from intracellular stores into the cytosol is used as a signaling mechanism by virtually all cell types to regulate functions as diverse as secretion, contraction, proliferation, and cell death. Advances in observational techniques have revealed complex patterns of intracellular Ca2+ that serve to selectively regulate specific cellular responses, and are constructed hierarchically through the activity of individual ion channels, multiple channels within clusters, and interactions between clusters. It is impossible to resolve all these scales simultaneously in a single experiment and the shorter time and distance scales cannot be resolved by any available experimental approaches. We therefore propose to use a tightly integrated approach of modeling, electrophysiology, and high-resolution cellular calcium imaging to illuminate the mechanisms by which "elementary" Ca2+ events are triggered and coupled to produce global cellular calcium signals. Specific aims are to describe (i) the kinetic mechanisms underlying the flux of calcium through single channels, (ii) the functional coupling between individual channels within a cluster, and (iii) the coordination between clusters allowing the propagation of global signals and the effects of buffers on this process. Numerical models will be constructed based on hypotheses and parameter values derived from patch-clamp and confocal cellular imaging experiments, and will be iteratively tested by comparison with observations and by their predictive power. Our overall goal is to develop a comprehensive model of intracellular Ca2+ signaling that is consistent with a multitude of observations, has predictive value, and extends to crucial - but experimentally inaccessible -space and time scales (nanometers and microseconds). We will focus on inositol trisphosphate-mediated Ca2+ signaling, utilizing Xenopus oocytes as a well-characterized model system, but the emergent principles will be widely applicable across many cell types and species, as well as to calcium signalling mediated by ryanodine receptors.