TpI2 Kinase in Macrophage Activation by Microbes

TpI2 激酶在微生物激活巨噬细胞中的作用

• 批准号: 6700336
• 负责人: Shao-Cong Sun
• 金额: $ 33.33万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6700336
• 关键词: biological signal transduction; enzyme activity; enzyme induction /repression; enzyme mechanism; immune response; laboratory mouse; leukocyte activation /transformation; lipopolysaccharides; macrophage; nuclear factor kappa beta; protein degradation; protein kinase; protein protein interaction; toll like receptor

DESCRIPTION (provided by applicant): Our long-range goal is to dissect the signaling pathways mediating microbial induction of inflammatory mediators in macrophages. This knowledge is important for rational design of strategies to modulate immune responses against infections and to treat inflammation and septic shock. The overall objective of this application is to elucidate the molecular mechanisms regulating the signaling function of a protein kinase, Tpl2. Recent genetic studies have revealed a central role for Tpl2 in mediating macrophage activation by lipopolysaccharide (LPS), a potent inflammatory elicitor from Gram-negative bacteria. However, how the function of Tpl2 is regulated remains unknown. The studies proposed in this grant application are based on a large body of preliminary data generated by the applicants. We have demonstrated that in macrophages, Tpl2 forms a latent complex with the nfkbl gene product p105. Genetic and biochemical evidence suggests that both the stability and kinase function of Tpl2 are tightly controlled by its partner p105. Interestingly, LPS-stimulated Tpl2 activation is correlated with its phosphorylation and release from p105. We have further observed that LPS also stimulates the degradation of Tpl2, which may serve as a negative feedback mechanism to prevent uncontrolled activation of this key inflammatory mediator. Based on these findings, the central hypothesis to be tested is that the signaling function of Tpl2 is regulated by both positive and negative mechanisms, which involve its modification by upstream signals and dynamic interaction with p105. To accomplish the objective of this application, we will pursue four specific aims: (1) define the biochemical mechanisms mediating Tpl2 activation; (2) investigate how Tpl2 is targeted for degradation; (3) determine the mechanisms by which p105 regulates the stability and function of Tpl2; and (4) identify upstream signaling molecules involved in Tpl2 activation. At the completion of this research, we expect to have determined how the signaling function of Tpl2 is positively and negatively regulated in the LPS signaling cascade. We also expect to have isolated novel signaling molecules participating in this important innate immune response.

描述（由申请人提供）：我们的远程目标是剖析介导巨噬细胞中炎症介质的微生物诱导的信号通路。这些知识对于合理设计的策略很重要，以调节针对感染并治疗炎症和败血性休克的免疫反应。该应用的总体目的是阐明调节蛋白激酶TPL2信号传导功能的分子机制。最近的遗传研究表明，TPL2在介导脂多糖（LPS）的巨噬细胞激活中的核心作用，脂多糖（LPS）是革兰氏阴性细菌的有效炎症性诱发剂。但是，如何调节TPL2的功能仍然未知。本赠款申请中提出的研究基于申请人产生的大量初步数据。我们已经证明，在巨噬细胞中，TPL2与NFKBL基因产物P105形成了潜在的复合物。遗传和生化证据表明，TPL2的稳定性和激酶功能都由其伴侣P105紧密控制。有趣的是，LPS刺激的TPL2激活与其磷酸化并从P105释放相关。我们进一步观察到，LP还刺激TPL2的降解，这可能是防止这种关键炎症介质的不受控制激活的负反馈机制。基于这些发现，要测试的中心假设是TPL2的信号传导函数受正和负机制的调节，这涉及通过上游信号的修饰以及与P105的动态相互作用。为了实现此应用的目标，我们将追求四个具体目标：（1）定义介导TPL2激活的生化机制； （2）研究如何将TPL2靶向降解； （3）确定P105调节TPL2的稳定性和功能的机制； （4）识别参与TPL2激活的上游信号分子。这项研究完成时，我们希望确定在LPS信号级联中TPL2的信号传导函数如何积极和负调节。我们还期望有参与这一重要的先天免疫反应的孤立的新型信号分子。