Coordinate Regulation Of Nuclear DGK-theta and PLD

核 DGK-theta 和 PLD 的协调调控

• 批准号: 7267587
• 负责人: Daniel M. Raben
• 金额: $ 29.55万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7267587
• 关键词: 1,2-diacylglycerol; 1-Phosphatidylinositol 3-Kinase; Agonist; Area; Binding; Cell Nucleus; Cell membrane; Cell surface; Coupling; Cytoplasm; Data; Diacylglycerol Kinase; Diglycerides; Elements; Enzymes; Event; Fibroblasts; GTP-Binding Proteins; Generations; Growth; Heterotrimeric GTP-Binding Proteins; Laboratories; Lipids; Mediating; Metabolism; Molecular; Molecular Weight; Nuclear; Nuclear Protein; Nuclear Proteins; Nuclear Translocation; Pathway interactions; Phosphatidic Acid; Phosphoinositide-3-Kinase, Catalytic, Gamma Polypeptide; Phospholipase D; Phosphotransferases; Physiological; Play; Production; Protein Kinase C; Protein Kinase C Alpha; Protein Subunits; Publishing; Receptor Activation; Regulation; Research; Role; Scheme; Signal Transduction; Signaling Molecule; System; Testing; Thrombin; Thrombin Receptor; Time; Tissues; Wound Healing; alpha-Thrombin; in vivo; insight; interest; lipid metabolism; response; rhoA GTP-Binding Protein

DESCRIPTION (provided by applicant): This proposal focuses on an emerging signal transduction paradigm which counters the prevailing view that the nucleus is a passive recipient of signals produced at the plasma membrane. Our laboratory and others have shown that receptor activation at the cell surface results in regulation of nuclear enzymes that produce and modify potent lipid signaling molecules. While this area has garnered increasing interest, we still understand neither the molecular aspects of the regulation nor the precise physiological roles of the induced lipid metabolism. The proposed studies aim at elucidating key elements of this signal transduction mechanism and its functional consequences. We find that the small molecular weight GTP-binding protein RhoA reciprocally regulates two signaling enzymes, diacylglycerol kinase-theta and phospholipase D, at the nucleus in response to alpha-thrombin stimulation of fibroblasts. We have termed this regulation the "RhoA Switch". We predict that the resulting modulation of diacylglycerol and phosphatidic acid levels and molecular composition have important physiological consequences such as the regulation of nuclear localization and activity of protein kinase C-alpha. Two heterotrimeric GTP-binding proteins, Gq and G13, and the lipid kinase PI 3-kinase mediate thrombin activation of this pathway. We hypothesize that; alpha-thrombin, after initiating an early Gq-dependent increase in nuclear diacylglycerol kinase-theta activity, stimulates a G13/PI 3-kinase-dependent nuclear translocation of RhoA that acts as a temporal "switch" to inhibit nuclear diacylglycerol kinase-theta while activating nuclear phospholipase D. We will test the hypothesis that Gq is essential for the induced increase in nuclear diacylglycerol kinase-theta activity, and identify the diacylglycerol-theta domains essential for its nuclear translocation in Aim I. Aim II will determine the molecular mechanism of the RhoA Switch by testing whether PI 3-kinase activation is responsible for nuclear RhoA translocation. Further, we will determine the molecular interactions between RhoA, diacylglycerol kinase-theta and phospholipase D. The physiological consequences of the RhoA Switch will be examined in Aim III. We will focus on the effect of the Switch on nuclear protein kinase C-alpha activity, composition of nuclear phosphatidic acids, and growth. We believe that an understanding of nuclear lipid signaling is key to our ability to intervene in events such as wound repair and tissue remodeling.

描述（由申请人提供）：该提案的重点是新兴信号转导范式，该范式反驳了核心是在质膜上产生的信号的被动接收者的普遍观点。我们的实验室和其他实验室表明，细胞表面的受体激活导致调节产生和修饰有效脂质信号分子的核酶。尽管该领域引起了人们的兴趣，但我们仍然既不了解调节的分子方面，也不了解诱导的脂质代谢的精确生理作用。拟议的研究旨在阐明该信号转导机制及其功能后果的关键要素。我们发现，小分子量GTP结合蛋白RhoA在细胞核上响应于α-脑包刺激成纤维细胞，从而在细胞核上相互调节两种信号传导酶，二酰基甘油激酶-THETA和磷脂酶D。我们已经将此法规称为“ Rhoa Switch”。我们预测，二酰基甘油和磷脂酸水平和分子组成的调节具有重要的生理后果，例如调节核定位和蛋白激酶C-α的活性。两种异三聚体GTP结合蛋白GQ和G13，以及该途径的脂质激酶PI 3-激酶介导凝血酶激活。我们假设这一点； alpha-thrombin, after initiating an early Gq-dependent increase in nuclear diacylglycerol kinase-theta activity, stimulates a G13/PI 3-kinase-dependent nuclear translocation of RhoA that acts as a temporal "switch" to inhibit nuclear diacylglycerol kinase-theta while activating nuclear phospholipase D. We will test the hypothesis that Gq is essential for the induced increase在核二酰基甘油激酶-THETA活性中，并确定AIM I中其核易位至关重要的二酰基甘油 - theta结构域，AIM II将通过测试PI 3-激酶激活是否负责核RhoA易位来确定RhoA转换的分子机制。此外，我们将确定RhoA，二酰基甘油激酶-THETA和磷脂酶D之间的分子相互作用。RHOA开关的生理后果将在AIM III中检查。我们将重点关注转换对核蛋白激酶C-α活性，核磷脂酸的组成和生长的影响。我们认为，了解核脂质信号是我们干预伤口修复和组织重塑等事件的能力的关键。