Unexpected roles of phosphoinositides in the nucleus

磷酸肌醇在细胞核中的意外作用

• 批准号: 10711033
• 负责人: Suyong Choi
• 金额: $ 35.67万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2028-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10711033
• 关键词: 1-Phosphatidylinositol 4-Kinase; Autoimmunity; Belief; Biochemical; Biological; Cell Nucleus; Cell physiology; Cells; Chromatin; Complex; Cytoskeleton; DNA Double Strand Break; DNA Repair; Ensure; Enzymes; Epigenetic Process; Functional disorder; Gene Expression; Generations; Goals; Health; Human; Knowledge; Link; Lipids; Malignant Neoplasms; Mediating; Metabolic Diseases; Microscopic; Minor; Molecular; Nature; Neurodegenerative Disorders; Nuclear; Pathogenesis; Phosphatidylinositols; Phospholipids; Phosphotransferases; Positioning Attribute; Process; Proteins; Proteomics; RNA Processing; Regulation; Repression; Research; Role; Signal Pathway; Signal Transduction; Stimulus; Transcription Coactivator; Transcriptional Regulation; cohort; genetic corepressor; genome-wide; genome-wide analysis; high resolution imaging; human disease; innovation; insight; novel; novel strategies; programs; recruit; spatiotemporal; tool; trafficking; transcription factor

PROJECT SUMMARY / ABSTRACT Phosphoinositides (PIs) are a minor class of phospholipids often comprising less than 1% of the cellular lipid cohort. Despite the low abundance, PIs have huge impacts on cell physiology and alterations of PI signaling pathways are associated with the pathogenesis of many human diseases including neurodegenerative diseases, metabolic disorders, autoimmunity, and cancer. This pathophysiological importance is largely due to the signaling roles of PIs which depend on the subcellular distribution of PIs and on key interactions between PIs and PI effectors. A twist in PI signaling is that in contrast to general belief, a substantial fraction of PIs is found in non-membranous nuclear compartments. The nature and functions of nuclear PIs remains largely unknown due to the lack of systematic studies of nuclear PIs and PI effectors. We have expertise in defining and characterizing novel PI effector proteins involved in key signaling pathways including vesicular trafficking, cytoskeleton dynamics, and transcription regulation. Since PI kinases are often associated with PI effectors thus ensuring PI generation is spatiotemporally linked to PI effector activation, we have performed proteomic analyses to identify the interactomes of the nuclear PI-generating kinases. Out of these proteomic screens, we have validated several nuclear complexes that associate with nuclear PI kinases or with PIs themselves. The validated complexes include transcription factors and coactivators, epigenetic enzymes and associated corepressors, the DNA repair machinery, and factors involved in RNA processing. We recently discovered that nuclear PIs accumulate at distinct subnuclear regions such as nuclear speckles and DNA double-strand breaks. Based on our novel discoveries of PIs and PI kinases interacting with effectors in the nucleus, the overarching goal of my research program is to decipher the signaling pathways emanating from the nuclear PIs. Our overall hypothesis is that upon suitable stimuli the activation of nuclear PI kinase at specific subnuclear compartments elevates the local concentration of nuclear PIs and these nuclear PI foci function as platforms to regulate PI effectors recruited to the foci mediating transcription regulation and assembly of complexes that regulate epigenetic changes. The goals of my research programs for the next five years include dissecting the nature and subnuclear distribution of nuclear PIs using novel microscopic tools which will enable us to obtain high resolution images of the nuclear PIs, defining the new roles of PIs regulating chromatin positioning to nuclear speckles, and investigating novel roles of nuclear PIs in regulating gene expression with focuses on transcription regulation and epigenetic repression with innovative cell biological, genome-wide, and biochemical approaches. Upon the completion of the research programs, we will obtain insight into the unexpected roles and molecular mechanism of PIs in the nucleus, with the goal of identifying novel strategies for targeting the nuclear PI signaling pathways dysregulated in diverse human disease.

项目概要/摘要 磷脂肌醇 (PI) 是一小类磷脂，通常占细胞脂质的比例不到 1% 队列。尽管丰度较低，但 PI 对细胞生理学和 PI 信号传导的改变具有巨大影响 途径与许多人类疾病的发病机制有关，包括神经退行性疾病、 代谢紊乱、自身免疫和癌症。这种病理生理学的重要性很大程度上是由于 PI 的信号传导作用取决于 PI 的亚细胞分布以及 PI 之间的关键相互作用 和 PI 效应器。 PI 信号传递的一个扭曲之处在于，与普遍看法相反，大部分 PI 是被发现的 在非膜核区室中。核PI的性质和功能仍然知之甚少 由于缺乏对核PI和PI效应子的系统研究。我们拥有定义和 表征参与关键信号传导途径（包括囊泡运输）的新型 PI 效应蛋白， 细胞骨架动力学和转录调控。由于 PI 激酶通常与 PI 效应子相关，因此 确保 PI 生成与 PI 效应器激活在时空上相关，我们进行了蛋白质组学分析 鉴定核 PI 生成激酶的相互作用组。从这些蛋白质组筛选中，我们得到了 验证了几种与核 PI 激酶或 PI 本身相关的核复合物。经验证的 复合物包括转录因子和共激活因子、表观遗传酶和相关的辅阻遏物、 DNA 修复机制以及 RNA 加工中涉及的因素。我们最近发现核PI 积累在不同的亚核区域，例如核斑点和 DNA 双链断裂。基于 我们关于 PI 和 PI 激酶与细胞核中效应子相互作用的新发现，总体目标 我的研究项目是破译核 PI 发出的信号通路。我们的整体 假设是，在适当的刺激下，特定亚核区室中核 PI 激酶的激活 提高核 PI 的局部浓度，这些核 PI 焦点可作为调节 PI 的平台 效应子被招募到介导转录调控和调节复合物组装的焦点 表观遗传变化。我未来五年研究计划的目标包括剖析自然和 使用新型显微工具研究核 PI 的亚核分布，这将使我们能够获得高分辨率 核 PI 的图像，定义了 PI 调节染色质定位到核斑点的新作用， 并研究核 PI 在调节基因表达中的新作用，重点关注转录调控 以及通过创新的细胞生物学、全基因组和生化方法进行表观遗传抑制。于 研究计划完成后，我们将深入了解意想不到的作用和分子机制 细胞核中 PI 的变化，目的是确定针对核 PI 信号通路的新策略 在多种人类疾病中失调。