Cardiac function and PIP2

心脏功能和 PIP2

• 批准号: 7150002
• 负责人: DONALD W HILGEMANN
• 金额: $ 36.98万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-15 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7150002
• 关键词: 1,2-diacylglycerol; Address; Affect; Animals; Area; Biological Assay; Cardiac; Cardiac Myocytes; Cell Line; Cell membrane; Cell surface; Cells; Coupled; Cyclic AMP-Dependent Protein Kinases; Cytoskeleton; Data; Degradation Pathway; Diglycerides; Dopamine; Dyes; Electric Capacitance; Electric Stimulation; Endocytosis; Event; Exocytosis; Experimental Models; Fluorescent Probes; Free Radical Scavenging; Frequencies; Golgi Apparatus; Growth; Heart; Heart Hypertrophy; High Pressure Liquid Chromatography; Inositol; Intervention; Ions; Label; Lipids; Localized; Measurement; Membrane; Membrane Fusion; Membrane Protein Traffic; Metabolic; Metabolism; Methods; Modeling; Monitor; Movement; Mus; Muscle Cells; Myocardial; Optical Methods; Oxygen; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipids; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiology; Process; Protein Overexpression; Proteolysis; Publications; Publishing; Radio; Range; Regulation; Research Personnel; Resolution; Retrieval; Role; Sarcolemma; Second Messenger Systems; Secretory Vesicles; Serine; Serine/Threonine Phosphorylation; Signaling Molecule; Signaling Protein; Standards of Weights and Measures; Stretching; Surface; Testing; Tissues; Transcriptional Activation; Transgenic Mice; Transgenic Organisms; Up-Regulation; Vesicle; Work; cytokine; falls; heart function; improved; inorganic phosphate; patch clamp; phosphatidylinositol phosphate; prevent; programs; response; second messenger; trafficking; 1,2-diacylglycerol; Address; Affect; Animals; Area; Biological Assay; Cardiac; Cardiac Myocytes; Cell Line; Cell membrane; Cell surface; Cells; Coupled; Cyclic AMP-Dependent Protein Kinases; Cytoskeleton; Data; Degradation Pathway; Diglycerides; Dopamine; Dyes; Electric Capacitance; Electric Stimulation; Endocytosis; Event; Exocytosis; Experimental Models; Fluorescent Probes; Free Radical Scavenging; Frequencies; Golgi Apparatus; Growth; Heart; Heart Hypertrophy; High Pressure Liquid Chromatography; Inositol; Intervention; Ions; Label; Lipids; Localized; Measurement; Membrane; Membrane Fusion; Membrane Protein Traffic; Metabolic; Metabolism; Methods; Modeling; Monitor; Movement; Mus; Muscle Cells; Myocardial; Optical Methods; Oxygen; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipids; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiology; Process; Protein Overexpression; Proteolysis; Publications; Publishing; Radio; Range; Regulation; Research Personnel; Resolution; Retrieval; Role; Sarcolemma; Second Messenger Systems; Secretory Vesicles; Serine; Serine/Threonine Phosphorylation; Signaling Molecule; Signaling Protein; Standards of Weights and Measures; Stretching; Surface; Testing; Tissues; Transcriptional Activation; Transgenic Mice; Transgenic Organisms; Up-Regulation; Vesicle; Work; cytokine; falls; heart function; improved; inorganic phosphate; patch clamp; phosphatidylinositol phosphate; prevent; programs; response; second messenger; trafficking

Phosphatidylinositol-4,5,-bis-phosphate (PIP2) is the precursor of inositol-trisphosphate (IP3), diacylglycerol (DAG), and phosphatidylinositol-trisphosphate (PIP3). It also anchors cytoskeleton and numerous signaling molecules at the plasmalemma, and its metabolism is closely coupled to membrane trafficking. In addition, it modulates profoundly the function of several cardiac ion transporters and channels. This application addresses how PIP2 is regulated in heart and how PIP2 metabolism is related to membrane turnover at the cardiac sarcolemma. As suggested by Preliminary Data, we will test whether PI4-kinases are regulated by serine/threonine phosphorylation and whether lipid phosphatases are regulated by surface membrane insertion and oxygen-dependent proteolysis. As a new experimental model, we have generated transgenic mice with cardiac-specific over-expression of the type2c_ PI4-kinase (PI4K2a). This kinase localizes primarily to Golgi and internal membranes, and its over-expression is associated with high-grade cardiac hypertrophy and up-regulation of ECC. We will now test how membrane trafficking to and away from the cardiac sarcolemma is affected using (1) fluorescent membrane dyes, (2) a new amperometric method to monitor surface membrane fusion events, and (3) high resolution capacitance measurements in on-cell patch clamp configuration. Preliminary Data suggests that PKC's may activate PI4K2Gt on internal membranes, thereby initiating movement of vesicles containing lipid phosphatases to the sarcolemma. Insertion at the sarcolemma appears to be activated directly by DAG, whereby subsequent depletion of sarcolemmal PIP2 would prevent endocytosis and favor the expansion of the sarcolemma. Complementary to studies of PI4K2(x, we will test whether the type 21_ PI4-kinase (PI4K213) is the major sarcolemmal PI4-kinase and whether its regulation may be tied to the regulation of cardiac transporters and channels. Finally, the hypothesis will be tested that PIP2 metabolism is inherently sensitive to membrane tension and curvature, as well as to myocyte stretch (i.e. the cardiac preload).

磷脂酰肌醇-4,5，-bis-磷酸（PIP2）是肌醇 - 三磷酸（IP3），二酰基甘油的前体 （DAG）和磷脂酰肌醇三磷酸盐（PIP3）。它还锚定细胞骨架和许多信号传导 血浆中的分子及其代谢与膜运输密切相关。另外，它 深刻调节了几种心脏离子转运蛋白和通道的功能。此应用程序 解决了PIP2在心脏中的调节方式以及PIP2代谢与膜转换的关系 心脏肌肉发达。正如初步数据所建议的那样，我们将测试PI4-激酶是否受到调节 丝氨酸/苏氨酸磷酸化以及脂质磷酸酶是否由表面膜插入调节 和氧依赖性蛋白水解。作为一种新的实验模型，我们已经与 Type2C_ PI4-激酶（PI4K2A）的心脏特异性过表达。这种激酶主要定位于高尔基 和内部膜及其过表达与高级心脏肥大和 ECC上调。现在，我们将测试膜贩运如何与心脏肌脱落 使用（1）荧光膜染料受影响，（2）一种新的安培方法来监测表面 膜融合事件，（3）在电池贴片夹中的高分辨率电容测量值 配置。初步数据表明，PKC可能会在内部膜上激活PI4K2GT，从而 引发含有脂质磷酸酶向肌膜的囊泡的运动。插入肌肉 似乎是通过DAG直接激活的，随后的肌膜PIP2耗竭将阻止 内吞作用并有利于肌膜扩张。互补的PI4K2研究（X，我们将测试 21_ PI4-激酶类型（PI4K213）是否是主要的肌肌Pi4-激酶，以及其调节是否可以 与心脏转运蛋白和通道的调节有关。最后，将检验假设PIP2 代谢对膜张力和曲率以及对心肌伸展的敏感（即 心脏预紧力）。