Regulation of phosphoinositide metabolism and calcium dynamics in the neocortex

项目概要/摘要： 新皮层是哺乳动物中枢神经系统的特有结构。在人类中，大脑皮层 参与高级大脑功能，如认知和语言。新皮层的所有投射神经元 是从端脑侧脑室表面的一个共同的神经祖细胞库中产生的。 有丝分裂后投射神经元必须从增殖龛迁移到其预期的皮质层， 成熟并建立功能性突触联系。PN迁移的失调具有破坏性的 对人类健康的后果，并导致一系列的神经元迁移障碍，破坏神经元的功能。 电路和/或脑形态，导致认知问题，神经精神疾病，癫痫，和 神经解剖畸形这个项目的首要目标是确定新的分子机制 指导投射神经元迁移，迁移结束，并在新皮层中的最终位置定居。 最近，我们已经确定了E3泛素连接酶CRL 5作为迁移和最终定位的关键调节因子。 皮层的投射神经元。在这里，我们的目标是了解CRL 5依赖的分子机制， 控制锥体神经元迁移和终止。我们的初步数据表明，CRL 5调节的水平， 磷脂酰肌醇4，5-二磷酸（PIP 2）和 3，4，5-三磷酸磷脂酰肌醇（PIP 3）。我们的数据还表明， 通过对抗磷脂酰肌醇4-磷酸5-激酶（PIP 5 K）的活性来调节PIP 2和PIP 3水平 和磷酸肌醇3-激酶（PI 3 K），其分别合成PIP 2和PIP 3。此外，CRL 5还 通过调节钙离子事件的频率来控制钙离子动力学，这对锥体神经元至关重要 迁移该提案旨在解决CRL 5在投射神经元迁移和皮质神经元迁移过程中的作用。 通过回答以下问题，了解发展情况： 1)CRL 5如何调节PIP 5 K和PI 3 K活性以控制磷酸肌醇水平？，2)CRL 5是否调节 PIP 2和PIP 3水平控制投射神经元迁移？3)CRL 5是否参与细胞内Ca 2+动态 投射神经元通过控制Ca 2+通道活性/定位？，和4）CRL 5依赖性调节 PIP 2和PIP 3水平直接影响Ca 2+动态？该项目的成功完成将提供 第一个详细的CRL 5如何控制投射神经元迁移和终止的分子框架， 协调皮质形态发生，并将CRL 5鉴定为磷酸肌醇代谢的新调节剂， 神经系统中的Ca 2+动力学。该项目的完成将为治疗提供潜在的靶点 神经元迁移障碍的干预。

Project Summary/Abstract: The neocortex is an exclusive structure of the mammalian central nervous system. In humans, the neocortex is involved in higher-order brain functions such as cognition and language. All projection neurons in the neocortex are born from a common pool of neural progenitors at the surface of the lateral ventricles of the telencephalon. Post-mitotic projection neurons must migrate from the proliferative niche to their intended cortical layers in order to mature and establish functional synaptic contacts. Misregulation of PN migration has devastating consequences for human health and results in a series of neuronal migration disorders that disrupt neural circuitry and/or brain morphology, leading to cognition problems, neuropsychiatric disease, epilepsy, and neuroanatomical malformations. The overarching goal of this project is to define novel molecular mechanisms that instruct projection neuron migration, migration ending, and settling in their final position in the neocortex. Recently, we have identified the E3 ubiquitin ligase CRL5 as a key regulator of migration and final positioning of projection neurons in the cortex. Here, we aim to understand the CRL5-dependent molecular mechanisms that control pyramidal neuron migration and termination. Our preliminary data indicate that CRL5 regulates the levels of two crucial phosphoinositide signaling lipids, phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 3,4,5-trisphosphate (PIP3) in projection neurons. Our data also suggests that CRL5 regulates PIP2 and PIP3 levels by opposing the activity of the phosphatidylinositol 4-phosphate 5-kinase (PIP5K) and phosphoinositide 3-kinases (PI3K), which synthesizes PIP2 and PIP3, respectively. Moreover, CRL5 also controls Ca2+ dynamics by regulating the frequency of Ca2+ events, which are crucial for pyramidal neuron migration. This proposal aims to address the role of CRL5 during projection neuron migration and cortical development by answering the following questions: 1) How does CRL5 regulate PIP5K and PI3K activity to control phosphoinositide levels?, 2) Is CRL5 regulating PIP2 and PIP3 levels to control projection neuron migration?, 3) Does CRL5 participate in Ca2+ dynamics in projection neurons by controlling Ca2+ channels activity/localization?, and 4) Does CRL5-dependent regulation of PIP2 and PIP3 levels directly affect Ca2+ dynamics? The successful completion of the project will provide the first detailed molecular framework of how CRL5 controls projection neuron migration and termination to orchestrate cortical morphogenesis and identify CRL5 as a novel regulator of phosphoinositides metabolism and Ca2+ dynamics in the nervous system. Completion of this project will offering potential targets for therapeutic intervention in neuronal migration disorders.