REGULATION OF LIVER FUNCTION BY MAPK/MKP-1

这个项目的主要目标是了解在健康状态下控制肝功能的分子机制。 和疾病。具体地说，这个项目的目的是了解局部核内和胞内钙是如何 信号与丝裂原活化蛋白激酶(MARK)信号转导通路整合 控制肝脏的生长、再生和代谢。MAPK受到一个家族的负面调控 被称为标记磷酸酶(MKPs)的酶。这个实验室最近的研究表明， 核定位的MKP家族成员MKP-1对MAPKs的负性调控起着至关重要的作用。这些 在体内观察得到支持，我们发现缺乏MKP-1表达的小鼠表现出 肝脏MAPK活性增强与肝脂代谢增强和 对脂肪肝的抵抗。我们提供初步数据来支持一种新的信令 胞浆和胞核钙信号差异调控MKP-1转录的研究范式 一种积极的态度和消极的态度。钙对细胞核内MKP-1的离散调节 控制MAPK介导的基因表达。我们假设局部钙信号调节MKP-1 限制MAPK介导的基因大小和时空动力学的表达 肝脏生长、再生和代谢动态平衡所需的活动。我们将在以下方面测试这一假设 三个具体目标。目标1将确定核质和细胞质的不同效应的分子基础 钙通过干扰钙信号对这些亚细胞MKP-1基因转录的调节 使用先前开发的靶向钙结合蛋白的隔室。目标2将定义 MKP-1在肝脏中的核定位对其生理功能的重要性为了验证这一点，一本小说 以胞浆为靶点的MKP-1基因突变将被用诱导剂“敲入”小鼠体内。 CreLoxP方法。目标3将确定MKP-1在肝脏生长、再生和应激中的作用 管理使用MKP-1“敲除”小鼠。连同Nathanson和Ehrlich的项目，拟议中的分子， 该项目中的生化和遗传方法将建立一种新的信号传递模式 钙信号、MKP-1和MAPK介导的基因表达在肝功能调控中的作用

The broad goal of this project is to understand the molecular mechanisms that control liver function in health and disease. Specifically, the aim of this project is to understand how local nuclear and cytosolic calcium signals integrate with the mitogen-activated protein kinase (MARK) signal transduction pathway in the control of liver growth, regeneration, and metabolism. The MAPKs are negatively regulated by a family of enzymes known as the MARK phosphatases (MKPs). Recent work from this laboratory has shown that the nuclear localized MKP family member, MKP-1, is essential for the negative regulation of the MAPKs. These observations are supported in vivo where we have discovered that mice lacking expression of MKP-1 exhibit enhanced MAPK activation in the liver which correlates with enhanced hepatic lipid metabolism and resistance to the acquisition of a fatty liver. We present preliminary data to support a new signaling paradigm in which cytosolic and nuclear calcium signals differentially regulate the transcription of MKP-1 in a positive and negative manner, respectively. This discrete regulation of MKP-1 in the nucleus by calcium controls MAPK-mediated gene expression. We hypothesize that local calcium signals regulates MKP-1 expression which serves to limit the magnitude and spatio-temporal kinetics of MAPK-mediated gene activity required for liver growth, regeneration, and metabolic homeostasis. We will test this hypothesis in three specific aims. Aim 1 will define the molecular basis for the differential effects of nuclear and cytosolic calcium on the regulation of MKP-1 gene transcription by disrupting calcium signaling in these sub-cellular compartments using previously developed targeted calcium-binding proteins. Aim 2 will define the importance of MKP-1 nuclear localization for its physiological function in the liver. To test this, a novel genetic mutation in MKP-1 that targets it to the cytosol will be "knocked-in" to mice using an inducible CreLoxP approach. Aim 3 will determine the role of MKP-1 on liver growth, regeneration, and stress management using MKP 1 "knock-out" mice. Together with projects by Nathanson and Ehrlich, the proposed molecular, biochemical and genetic approaches in this project will establish a new signaling paradigm between local calcium signals, MKP-1 and MAPK-mediated gene expression in the control of liver function.