SIGNAL TRANSDUCTION BY LYSOPHOSPHATIDIC ACID

溶血磷脂酸的信号转导

基本信息

批准号：
6626600
负责人：
JIE WU
金额：
$ 10.77万
依托单位：
UNIVERSITY OF SOUTH FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-01-01 至 2003-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6626600
关键词：
biological signal transduction calcium cell line enzyme activity enzyme induction /repression enzyme inhibitors epidermal growth factor free radical oxygen growth factor receptors lysophospholipids phosphatidate protein tyrosine kinase site directed mutagenesis

项目摘要

Lysophosphatidic acid (LPA) is a major mitogen in serum that regulates an array of cellular processes related to pathogenesis of cancer and other human diseases. Despite the central role of LPA in controlling cell growth and other cellular activities, very little is understood about the signaling mechanisms of LPA. While protein tyrosine phosphorylation has been recognized as an important signaling mechanism of LPA and other agonists of G protein-coupled receptors, it remains largely unknown how activation of G-proteins leads to tyrosine phosphorylation. To address this important question, LPA-induced tyrosine phosphorylation of the epidermal growth factor receptor (EGFR) will be studied. Based on our preliminary observations and increasing evidence of redox-regulation in cell signaling, it is postulated that LPA transactivates the EGFR by decreasing EGF receptor phosphatase activity through a mechanism mediated by calcium and reactive oxygen species (ROS). Three specific aims are proposed to critically evaluate key aspects of this hypothesis. In Specific Aim I, the requirement for intrinsic EGFR tyrosine kinase activity will be assessed using kinase- defective EGFR and new specific inhibitors for the EGFR. Effects of decreasing protein tyrosine phosphatase activity toward EGFR will also be examined. Alternatively, a novel sensitive approach is proposed to determine whether LPA activates the EGFR kinase. TO further evaluate whether LPA-induced tyrosine phosphorylation is catalyzed by intrinsic EGF receptor kinase or by another cellular kinase, Specific Aim II proposes phosphopeptide mapping and mutagenesis experiments to analyze LPA-induced tyrosine phosphorylation sites on the EGFR. In Specific Aim III, regulation of EGFR-dephosphorylating activity by LPA will be investigated both in vitro and in intact cells under conditions that redox-mediated changes can be detected, and the involvement of calcium and ROS will be evaluated. These studies not only will advance our understanding of signal transduction by LPA and G-proteins that control many cellular processes fundamental to the development of cancer and other human diseases, but also will stimulate further research in the emerging area of oxidative signaling.

溶血磷脂酸 (LPA) 是血清中的主要有丝分裂原，可调节一系列与癌症发病机制相关的细胞过程其他人类疾病。尽管 LPA 在控制中发挥着核心作用人们对细胞生长和其他细胞活动知之甚少关于LPA的信号传导机制。而蛋白质酪氨酸磷酸化已被认为是重要的信号传导机制 LPA 和 G 蛋白偶联受体的其他激动剂，它仍然很大程度上不知道 G 蛋白的激活如何导致酪氨酸磷酸化。为了解决这个重要问题，LPA 诱导表皮生长因子受体 (EGFR) 的酪氨酸磷酸化将被研究。根据我们的初步观察和不断增加细胞信号传导中氧化还原调节的证据，推测 LPA 通过降低 EGF 受体磷酸酶反式激活 EGFR 通过钙和活性氧介导的机制发挥活性物种（ROS）。提出了三个具体目标来严格评估这一假设的关键方面。在具体目标 I 中，要求内在 EGFR 酪氨酸激酶活性将使用激酶进行评估有缺陷的 EGFR 和新的 EGFR 特异性抑制剂。的影响降低蛋白酪氨酸磷酸酶对 EGFR 的活性也会被检查。或者，提出了一种新颖的敏感方法确定 LPA 是否激活 EGFR 激酶。进一步评估 LPA诱导的酪氨酸磷酸化是否是由内在的催化 EGF 受体激酶或另一种细胞激酶，Specific Aim II 提出磷酸肽作图和诱变实验来分析 LPA 诱导的 EGFR 酪氨酸磷酸化位点。特定目标 III、LPA对EGFR去磷酸化活性的调节将是在体外和完整细胞中进行了研究可以检测到氧化还原介导的变化，并且钙的参与并对 ROS 进行评估。这些研究不仅将推动我们了解 LPA 和 G 蛋白控制的信号转导许多细胞过程对于癌症的发展至关重要其他人类疾病，也将刺激进一步的研究氧化信号传导的新兴领域。