Phosphoinositide Signaling in the Cytosol and Nucleus

细胞质和细胞核中的磷酸肌醇信号转导

• 批准号: 10561701
• 负责人: Richard A. Anderson
• 金额: $ 70.71万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10561701
• 关键词: Agonist; Binding; Biological Process; Cardiovascular Diseases; Cell Nucleus; Cell Proliferation; Cell Survival; Cell membrane; Cell physiology; Cytosol; DNA Repair; Diabetes Mellitus; Diagnostic; Disease; EGF gene; Endosomes; Epidermal Growth Factor Receptor; Event; Gene Expression; Generations; Genes; Immune System Diseases; Link; MAP4; Malignant Neoplasms; Membrane; Microtubules; Neurodevelopmental Disorder; Neurons; Nuclear; Outcome; PDPK1 gene; PIK3CG gene; PTEN gene; Pathway interactions; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phosphotransferases; Polymerase; Process; Protein Dephosphorylation; Regulation; Research; Resistance; Role; Second Messenger Systems; Signal Pathway; Signal Transduction; Stress; System; TP53 gene; Therapeutic; Tumor Suppressor Proteins; biological adaptation to stress; cancer cell; inorganic phosphate; inositol polyphosphate multikinase; novel; receptor; scaffold

PROJECT SUMMARY. This research seeks to understand spatial phosphoinositide signaling (PI) mechanisms in the cytosol and nucleus. These pathways have broad implications for cancer, neurodevelopmental disorders, diabetes, and several congenital diseases. In the cytosol, agonists, such as EGF (and many others), activate signaling pathways that control most cellular functions. In the nucleus, these pathways are separate from known membrane compartments but control stress responses that impact DNA repair, cell survival, and other events. Agonists activated PI3K signaling occurs through the IQGAP1 scaffold that assembles multiple pathways including the PI 3-kinase and Erk pathways. Yet, how the IQGAPs assemble specific signaling pathways is not understood. We will focus on the assembly of the full PI 3-kinase pathway on IQGAPs. This includes the assembly of the PI 4-kinase (PI4KIII), type I PIP 5-kinase (PIPKI), PI3K, Ras, PDK1 and Akt into the scaffold. Remarkably, we show that IQGAP2 and IQGAP3 also assemble the PI 3-kinase pathway components but with different outcomes. IQGAP2 is tumor suppressor in cancer cells whereas IQGAP1 and IQGAP3 promote PI3K signaling and cell proliferation. Here, we will explore how receptors stimulate the assembly of the IQGAPs signaling pathways with an emphasis on the EGF receptor and IQGAP1-PI 3-kinase and Erk pathways. We will emphasize spatial PI 3-kinase signaling at endosomal compartments at proximity to microtubules by linkage with microtubule associated protein 4 (MAP4) that interacts with IQGAP1 and PI 3-kinase. The link between the cytosolic and nuclear PI signaling is the PIPKI, which generates PIP2 in the cytosol and nucleus Nuclear PI signaling remarkably is not associated with membrane compartments. We showed that a nuclear poly(A) polymerase, Star-PAP (for speckle targeted PIPKI regulated-poly(A) polymerase), associates with PIPKI and is activated by phosphatidylinositol-4,5-bisphosphate (PIP2). Star-PAP controls ~40% of genes and is regulated by many signals. Recently, we have shown that PIPKI also binds to the tumor suppressor p53, and that p53 is a PIP2 effector. The binding of PIP2 stimulates p53’s interactions with other nuclear factors that control p53 function. Both Star-PAP and p53 are also regulated by inositol polyphosphate multikinase (IPMK) that generates phosphatidylinositol-3,4,5-trisphosphate (PIP3) associated with p53, and nuclear PTEN that dephosphorylates this PIP3. We have identified Star-PAP and p53 as two key effectors of nuclear phosphoinositide signaling during stress signaling. This proposal will focus on the mechanism and impact of this stress pathway on Star-PAP functions. Remarkably the PIPn is so tightly associated with Star-PAP and p53 that it is stable to SDS-PAGE suggesting a covalent linkage and we will explore how PIP2 is linked to Star-PAP and p53. Is this covalent or a very tight interaction that is resistant to denaturation? Our findings indicate new avenues for potential therapeutic control of both the cytosolic and nuclear PI pathways as these pathways have fundamental implications in many disease processes but with an emphasis on cancer.

项目摘要。本研究旨在了解空间磷酸肌醇信号传导 (PI) 机制 这些途径对癌症、神经发育障碍、 糖尿病和一些先天性疾病在细胞质中，激动剂，例如 EGF（和许多其他），会被激活。 控制大多数细胞功能的信号通路 在细胞核中，这些通路与已知的通路是分开的。 膜隔室，但控制影响 DNA 修复、细胞存活和其他事件的应激反应。 激动剂激活的 PI3K 信号传导通过组装多个途径的 IQGAP1 支架发生 包括 PI 3 激酶和 Erk 通路，但 IQGAP 如何组装特定的信号通路尚不清楚。 我们将重点关注 IQGAP 上完整 PI 3 激酶途径的组装。 将 PI 4-激酶 (PI4KIII)、I 型 PIP 5-激酶 (PIPKI)、PI3K、Ras、PDK1 和 Akt 组装到 值得注意的是，我们表明 IQGAP2 和 IQGAP3 也组装 PI 3 激酶途径组件。 但 IQGAP2 是癌细胞的肿瘤抑制因子，而 IQGAP1 和 IQGAP3 则具有促进作用。 PI3K 信号传导和细胞增殖在这里，我们将探讨受体如何刺激 IQGAP 的组装。 我们将重点关注 EGF 受体和 IQGAP1-PI 3-激酶和 Erk 信号通路。 通过与微管附近的连接强调内体区室的空间 PI 3 激酶信号传导 微管相关蛋白 4 (MAP4) 与 IQGAP1 和 PI 3 激酶相互作用。 细胞质和细胞核 PI 信号传导是 PIPKI，它在细胞质和细胞核中生成 PIP2 核 PI 信号传导异常地与膜区室无关。 聚 (A) 聚合酶，Star-PAP（用于斑点靶向 PIPKI 调节聚 (A) 聚合酶），与 PIPKI 并由 4,5-二磷酸磷脂酰肌醇 (PIP2) 激活，Star-PAP 控制约 40% 的基因和 最近，我们发现 PIPKI 也与肿瘤抑制因子 p53 结合。 p53 是 PIP2 效应子 PIP2 的结合刺激 p53 与其他核因子的相互作用。 Star-PAP 和 p53 也受肌醇多磷酸激酶 (IPMK) 的调节。 产生与 p53 相关的磷脂酰肌醇-3,4,5-三磷酸 (PIP3) 和核 PTEN 我们已经确定 Star-PAP 和 p53 是核的两个关键效应子。 该提案将重点关注其机制和影响。 Star-PAP 功能的应激途径 值得注意的是，PIPn 与 Star-PAP 和 p53 密切相关。 它对 SDS-PAGE 稳定，表明存在共价连接，我们将探讨 PIP2 如何与 Star-PAP 连接并 p53. 这是共价还是非常紧密的相互作用，可以抵抗变性？ 用于细胞质和核 PI 途径的潜在治疗控制，因为这些途径具有 对许多疾病过程有根本性影响，但重点是癌症。