Phosphatidylinositol 4-Phosphate Hydrolysis in Spatiotemporal Cell Signaling

时空细胞信号传导中的磷脂酰肌醇 4-磷酸水解

• 批准号: 9420176
• 负责人: Alan V. Smrcka
• 金额: $ 29.47万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9420176
• 关键词: Address; Affect; Agonist; Apoptosis; Autoimmune Diseases; Binding; Biological; Calcium; Cardiac; Cardiac Myocytes; Cell Proliferation; Cell membrane; Cell physiology; Cells; Chronic; DNA biosynthesis; Data; Diabetes Mellitus; Diglycerides; Disease; Embryo; Endothelin; Enzymes; Fibroblasts; Functional disorder; G-Protein-Coupled Receptors; G-substrate; GTP-Binding Proteins; Goals; Golgi Apparatus; Growth; Heart Diseases; Hormone Receptor; Hydrolysis; In Vitro; Inositol; Laboratories; Link; Malignant Neoplasms; Malignant neoplasm of pancreas; Measures; Membrane; Metabolism; Molecular; Monitor; Mus; Neurotensin; Pancreas; Participant; Pathology; Pathway interactions; Phosphatidic Acid; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipase C; Phospholipids; Phosphoric Monoester Hydrolases; Physiological Processes; Physiology; Play; Prevalence; Process; Production; Protein Isoforms; Protein Kinase C; Protein Tyrosine Kinase; PubMed; Reaction; Receptor Activation; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Regulation; Role; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Source; Stimulation of Cell Proliferation; System; cell growth; cell type; experimental study; in vitro Model; novel; pancreatic cancer cells; phosphatidylinositol 4-phosphate; prevent; public health relevance; receptor; spatiotemporal

DESCRIPTION (provided by applicant): A major cellular signal transduction pathway activated by G protein-coupled receptors and receptor/non- receptor tyrosine kinases is the activation of phosphoinositide-specific phospholipase C (PI-PLC), to stimulate phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis and produce inositol 1,4,5 trisphosphate (IP3) and diacylglycerol (DAG). IP3 controls calcium release from internal stores and DAG regulates protein kinase C. Our laboratory has recently discovered an alternate substrate for PI-PLC activity in cardiac cells, phosphatidylinositol 4-phosphate (PI4P). Hydrolysis of PI4P by PLC produces inositol 1,4 bisphosphate (IP2) which is biologically inert, and DAG. In this application we propose to investigate the broader role for PI4P hydrolysis as source for long-term and localized DAG critical for maintaining compartmentalized and chronically activated protein kinase C and D (PKC and PKD) activities. Protein Kinase C activation is implicated in hundreds of chronic physiological processes. For example, a "PubMed" search of protein kinase C and cancer reveal close to 10,000 references. PKD activation, directly regulated by both PKC, and direct binding of DAG, has recently emerged as a key player in cell physiology and pathology. Thus the experiments outlined in this proposal have the potential to uncover an entirely new fundamental signaling mechanism with potential implications for regulation of a wide range of cell physiologies and pathophysiologies. These issues will be addressed with the following specific aims: 1: Prevalence of the PI4P signaling pathway in cells: We have clearly demonstrated in cardiac myocytes that stimulation of cells with endothelin leads to PI-PLC- dependent depletion of PI4P in the perinuclear Golgi apparatus. The goal of these experiments is to characterize and extend these observations to determine if PI4P hydrolysis plays a prominent role in cell signaling in general. 2: Mechanism for regulation of PI4P hydrolysis. Our preliminary data provide strong evidence for agonist regulated PI4P hydrolysis as a major contributor to long term IP and perhaps DAG production but the signaling pathways and enzymes involved in this process appear to be different depending on the receptor signaling mechanism and cell type. Here we will identify the molecular participants in the signaling pathways that regulate PI4P hydrolysis. 3: Role of PI4P in pancreatic cancer cell signaling, growth, apoptosis and Golgi function: PKC activation is involved in many cellular processes and diseases including cancer. In an established in vitro model of pancreatic cancer, PANC-1 cells, neurotensin potently stimulated PKC and PKD dependent DNA synthesis and cell proliferation and PKD inhibition prevents pancreatic cancer cell growth in vitro. Here we will examine the role of PI4P hydrolysis in activation of key components of this mitogenic signaling pathway and will determine its role in pancreatic cell mitogenesis.

描述（由申请人提供）：G蛋白偶联受体和受体/非受体酪氨酸激酶激活的主要细胞信号转导途径是激活磷酸肌醇特异性磷脂酶C（PI-PLC），以刺激磷脂酰肌醇4,5-二磷酸（PIP2）水解并产生肌醇1,4,5三磷酸（IP3）和二酰甘油（DAG）。 IP3 控制内部储存的钙释放，DAG 调节蛋白激酶 C。我们的实验室最近发现了心脏细胞中 PI-PLC 活性的替代底物， 磷脂酰肌醇 4-磷酸 (PI4P)。 PLC 水解 PI4P 产生生物惰性的肌醇 1,4 二磷酸 (IP2) 和 DAG。在此应用中，我们建议研究 PI4P 水解作为长期和局部 DAG 来源的更广泛作用，这对于维持区室化和长期激活的蛋白激酶 C 和 D（PKC 和 PKD）活性至关重要。蛋白激酶 C 激活与数百种慢性生理过程有关。例如，对蛋白激酶 C 和癌症的“PubMed”搜索显示了近 10,000 个参考文献。 PKD 激活直接受 PKC 和 DAG 直接结合的调节，最近已成为细胞生理学和病理学的关键参与者。因此，该提案中概述的实验有可能揭示一种全新的基本信号传导机制，对广泛的细胞生理学和病理生理学的调节具有潜在影响。这些问题将通过以下具体目标得到解决： 1：细胞中 PI4P 信号通路的普遍性：我们在心肌细胞中清楚地证明，用内皮素刺激细胞会导致核周高尔基体中 PI-PLC 依赖性的 PI4P 消耗。这些实验的目的是表征和扩展这些观察结果，以确定 PI4P 水解是否在细胞信号传导中发挥着重要作用。图2：PI4P水解调节机制。我们的初步数据提供了强有力的证据，证明激动剂调节的 PI4P 水解是长期 IP 甚至 DAG 产生的主要贡献者，但该过程中涉及的信号传导途径和酶似乎因受体信号传导机制和细胞类型而异。在这里，我们将确定调节 PI4P 水解的信号通路中的分子参与者。图3：PI4P在胰腺癌细胞信号传导、生长、凋亡和高尔基体功能中的作用：PKC激活参与包括癌症在内的许多细胞过程和疾病。在已建立的胰腺癌体外模型中，PANC-1 细胞中，神经降压素可有效刺激 PKC 和 PKD 依赖性 DNA 合成和细胞增殖，而 PKD 抑制可防止体外胰腺癌细胞生长。在这里，我们将研究 PI4P 水解在激活有丝分裂信号通路关键成分中的作用，并确定其在胰腺细胞有丝分裂中的作用。