RECEPTOR TYROSINE KINASE SIGNALING IN THE LIVER

描述：（改编自申请人摘要）一个重要的增长群体 因子和激素通过受体酪氨酸激酶作用于肝细胞 表皮生长因子（EGF）受体、肝细胞生长因子（EGF）受体等 因子/分散因子（HGF/SF）受体和胰岛素受体。尽管 我们对酪氨酸激酶分子机制的认识爆炸性增长 在过去的十年中，RTK信号通路的调节在 细胞水平仍然知之甚少。RTK激活多个信令 在早期衔接子/靶蛋白水平上经常重叠的途径 活化，刺激丝裂原活化蛋白激酶（MAPK）级联， 以及由它们的刺激物触发的转录事件。最近的文献数据， 也得到了霍洛坚科博士小组的研究结果的支持， 信号传导的特异性是由信号传导的时间、持续时间和幅度产生的。 激活不同的组件进程。然而，缺乏一个 RTK途径调控的定量和综合描述 阻碍了我们理解复杂的特定变化的原因， 信号反应及其对下游通路的直接影响。 该提案旨在通过定量动力学监测填补这一空白， RTK磷酸化和活化水平的计算分析 在用EGF、HGF/SF和胰岛素刺激的肝细胞中的途径中间体。 Kholodenko博士将采用生长因子的动力学和控制分析 完整肝细胞中的信号传导，以确定主要分子和动力学 控制RTK信号通路的因素。具体目标是：（1） 分析控制瞬态和持续响应模式的因素， 新鲜分离的EGF刺激靶向的多种信号蛋白 （2）分析早期信号转导的动力学和调控 （3）为了延长实验时间， 和计算分析，以调查对其他RTK介导的 信号，特别是HGF/SF和胰岛素，单独或组合。

DESCRIPTION: (adapted from applicant's abstract) An important group of growth factors and hormones acts on liver cells through receptor tyrosine kinases (RTKs) such as the epidermal growth factor (EGF) receptor, hepatocyte growth factor/scatter factor (HGF/SF) receptor and insulin receptor. Despite an explosive growth of our knowledge of molecular mechanisms of tyrosine kinase signaling during the past decade, the regulation of RTK pathways at the cellular level remains poorly understood. RTKs activate multiple signaling pathways that often overlap at the level of early adapter/target protein activation, stimulation of mitogen activated protein kinase (MAPK) cascades, and transcriptional events triggered by their stimuli. Recent literature data, also supported by findings from Dr. Kholodenko's group, suggest that specificity of signaling is generated by the timing, duration and amplitude of activation of the different component processes. However, the lack of a quantitative and integrative description of the regulation of RTK pathways hampers our understanding of the causes of particular alterations in complex signaling responses and their immediate consequences for downstream pathways. This proposal aims to fill this gap by quantitative kinetic monitoring and computational analysis of the levels of phosphorylation and activation of RTK pathway intermediates in hepatocytes stimulated with EGF, HGF/SF and insulin. Dr. Kholodenko will employ kinetic and control analyses of growth factor signaling in intact hepatocytes to identify the principal molecular and kinetic factors controlling RTK signaling pathways. The Specific Aims are: (1) To analyze the factors controlling transient and sustained response patterns in multiple signaling proteins targeted by EGF stimulation in freshly isolated hepatocytes; (2) To analyze the kinetics and control of early signaling responses of the EGF-stimulated MAPK cascade; (3) To extend the experimental and computational analyses to investigate the responses to other RTK-mediated signals, specifically HGF/SF and insulin, singly or in combination.