G-protein Regulation of the Phosphatidyl Inositol (3,4,5) Trisphosphate Signal

磷脂酰肌醇 (3,4,5) 三磷酸信号的 G 蛋白调节

• 批准号: 7570012
• 负责人: JAMES Carlton GARRISON
• 金额: $ 27.95万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2010-04-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7570012
• 关键词: Adenosine; Adhesions; Adrenergic Receptor; Alanine; Amino Acids; Blood Platelets; Cell Line; Cell Shape; Cell membrane; Cell physiology; Cells; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Enzymes; Event; G-Protein-Coupled Receptors; GTP-Binding Proteins; Generations; Goals; Hematopoietic; In Vitro; Knockout Mice; Laboratories; Ligands; Link; Lipids; Membrane; Molecular; Mutate; Neutrophil Activation; PH Domain; PTEN gene; Phosphatidylinositols; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphorylation Site; Phosphotransferases; Play; Protein Isoforms; Protein Kinase; Protein Kinase C; Proto-Oncogene Proteins c-akt; Recombinant Proteins; Regulation; Relative (related person); Research; Research Personnel; Role; Shapes; Signal Pathway; Signal Transduction; Signaling Molecule; Site; Specificity; Transmembrane Domain; Work; cell motility; dimer; eosinophil; inositol-1,4,5-trisphosphate 5-phosphatase; insight; macrophage; mast cell; methionyl-leucyl-phenylalanine; migration; myo-inositol-1 (or 4)-monophosphatase; neutrophil; receptor; receptor coupling; research study; response; src Homology Region 2 Domain; stoichiometry

G protein coupled receptors provide both positive and negative regulation of hematopoietic cells. In cells such as neutrophils, macrophages, mast cells and platelets, the p110y isoform of phosphatidylinositol (4,5) 3-kinase (Ptdlns 3-kinase) plays a major role in cell activation, shape changes and migration via generation of phosphatidylinositol (3,4,5) trisphosphate (PIPs). This lipid is an important signal that activates the phosphatidylinositol dependent protein kinase, PDK-1, leading to phosphorylation of protein kinase B and a host of cell responses. The levels of PIP3 in the membrane of these cells are also tightly controlled by a SH2 domain containing inositol 5-phosphatase, SHIP, that is regulated by multiple mechanisms. Activation of G protein coupled receptors linked to Gi stimulates the p110y isoform of Ptdlns 3-kinase 40-60 fold by releasing specific py dimers. Activation of G protein coupled receptors linked to Gs raise cyclic AMP and can markedly inhibit the response of hematopoietic cells to stimulatory ligands. Our research has provided clear evidence of the specific isoforms of the Py dimer which activate the p110y isoform of Ptdlns 3 kinase. Recent experiments uncover the exciting result that both the p110y isoform of Ptdlns 3-kinase and SHIP can be phosphorylated by the cyclic AMP dependent protein kinase. The ability of the Py dimer to activate p101/p110y is inhibited by phosphorylation. Phosphorylation of SHIP activates the enzyme. These results provide a possible molecular explanation for the ability of cyclic AMP to inhibit the response of hematopoietic cells. The goal for this project is to determine the importance of these phosphorylation events in cell function. This goal will be approached via 2 Specific Aims. Aim-1a: To determine the effects of phosphorylation on the activity of Ptdlns 3-Kinase in vitro. Aim-1b: To understand how phosphorylation of Ptdlns 3-Kinase regulates the function of the enzyme in three cell lines. Aim-2a: To explore the effects of phosphorylation on the activity of SHIP in vitro. Aim-2b: To understand how phosphorylation of SHIP regulates its function in the intact cell. Completion of these Aims will provide considerable understanding of the molecular events regulating the levels of PIP3 in all cells and should reveal mechanisms by which G protein coupled receptors stimulate and inhibit the function of hematopoietic cells.

G蛋白偶联受体同时提供造血细胞的阳性和阴性调节。在细胞中 例如中性粒细胞，巨噬细胞，肥大细胞和血小板，磷脂酰肌醇的p110y同工型（4,5） 3-激酶（PTDLNS 3-激酶）在细胞激活，形态变化和通过产生中起主要作用 磷脂酰肌醇（3,4,5）三磷酸盐（PIPS）。该脂质是激活的重要信号 磷脂酰肌醇依赖性蛋白激酶PDK-1，导致蛋白激酶B和A的磷酸化 细胞反应的宿主。这些细胞膜中的PIP3水平也由SH2紧密控制 含有肌醇5-磷酸酶的结构域，由多种机制调节。 g的激活 与GI相关的蛋白偶联受体刺激PTDLNS 3-激酶40-60倍的P110Y同工型通过释放 特定的PY二聚体。与GS相关的G蛋白偶联受体的激活会引起环状AMP，并且可以显着 抑制造血细胞对刺激配体的反应。我们的研究提供了明确的证据 PY二聚体的特异性同工型，该二聚体激活PTDLNS 3激酶的P110Y同工型。最近的 实验发现了PTDLNS 3-激酶和船的P110Y同工型都可以是令人兴奋的结果 由循环AMP依赖性蛋白激酶磷酸化。 PY二聚体激活的能力 P101/P110Y被磷酸化抑制。船的磷酸化激活酶。这些结果 提供可能的分子解释，以抑制造血的反应的能力 细胞。该项目的目标是确定这些磷酸化事件在细胞功能中的重要性。 该目标将通过2个特定目标实现。 AIM-1A：确定磷酸化对 PTDLNS 3-激酶在体外的活性。 AIM-1B：了解PTDLNS 3-激酶的磷酸化如何调节 酶在三个细胞系中的功能。 AIM-2A：探索磷酸化对 体外船的活动。 AIM-2B：了解船舶的磷酸化如何调节其功能 完整的细胞。这些目标的完成将提供对分子事件的充分了解 调节所有细胞中的PIP3水平，并应揭示G蛋白偶联受体的机制 刺激并抑制造血细胞的功能。