Regulation of Mitochondrial Morphology in Liver Cells

肝细胞线粒体形态的调节

• 批准号: 6935805
• 负责人: YISANG YOON
• 金额: $ 23.63万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6935805
• 关键词: SDS polyacrylamide gel electrophoresis; adenosine triphosphate; biological signal transduction; electron microscopy; fluorescence microscopy; guanosinetriphosphatases; immunoprecipitation; liver cells; mitochondria; mitochondrial membrane; morphology; polymerase chain reaction; protein kinase C; protein structure function; tissue /cell culture

DESCRIPTION (provided by applicant): The goal of this proposal is to study how hepatocytes control the number, shape, and distribution of mitochondria. It is well known that mitochondria perform vital cellular functions in the hepatocyte including ATP generation, calcium homeostasis, regulation of redox state, and participation in signaling cascades that can regulate cell death. While mitochondrial dynamics appear to play an important role in these processes, the molecular mechanisms by which these essential organelles change their form and cytoplasmic location are poorly understood. Recently, we and others have identified two large GTPases, DLP1 and Mfn, which are found to participate in maintaining normal mitochondrial morphology in yeast and rat hepatocytes by mediating membrane fission and fusion. DLP1 is a dynamin-like protein that is presumed to function in mitochondrial division via its GTPase activity while Mfn has been reported to be a major factor involved in mitochondrial fusion. Our published work and substantial preliminary data in hepatocytes support the central hypothesis of this proposal that hepatic mitochondrial morphology and function is maintained through the antagonistic action of two large GTPases, DLP1 and Mfn. This proposal describes novel in vivo and in vitro studies, combined with numerous molecular and immunological reagents that we have made, to define the role of DLP1 and Mfn in regulating mitochondrial shape in the hepatocyte and to provide important insights into how these large GTPases function. We will pursue three Specific Aims. First, using state-of-the-art microscopic imaging techniques, we will test the respective roles of DLP1 and Mfn in maintaining mitochondrial number and morphology in living hepatocytes. Second, structural studies will define, at a molecular level, how DLP1 acts to sever mitochondrial membranes and whether this severing activity is enhanced by putative binding partners that we have already identified. Third, we will define how cellular signaling cascades regulate DLP1 and Mfn activity to subsequently alter the form and function of hepatocyte mitochondria. Information gathered from these studies will greatly increase our understanding of how mitochondrial shape and number are regulated and contribute to hepatocellular physiology and injury in health and disease.

描述（由申请人提供）：该提案的目的是研究肝细胞如何控制线粒体的数量，形状和分布。众所周知，线粒体在肝细胞中执行重要的细胞功能，包括ATP产生，钙稳态，调节氧化还原状态以及参与可以调节细胞死亡的信号级联反应。尽管线粒体动力学在这些过程中似乎起着重要作用，但这些基本细胞器改变其形式和细胞质位置的分子机制却鲜为人知。最近，我们和其他人发现了两个大型GTPases DLP1和MFN，它们被发现参与通过介导膜裂变和融合来维持酵母和大鼠肝细胞中正常的线粒体形态。 DLP1是一种类动力蛋白样蛋白，假定通过其GTPase活性在线粒体分裂中起作用，而MFN据报道是与线粒体融合有关的主要因素。我们发表的肝细胞中发表的工作和大量初步数据支持了这一提议的中心假设，即通过两个大GTPases DLP1和MFN的拮抗作用来维持肝线粒体形态和功能。该提案描述了新型体内和体外研究，并结合了我们制作的许多分子和免疫学试剂，以定义DLP1和MFN在调节肝细胞中线粒体形状中的作用，并为这些大GTPase如何发挥作用。我们将追求三个具体目标。首先，使用最先进的显微成像技术，我们将测试DLP1和MFN在维持生命肝细胞中维持线粒体数和形态的各自作用。其次，结构研究将在分子水平上定义DLP1如何作用于切断线粒体膜，以及我们已经确定的假定结合伙伴是否可以增强这种断开活性。第三，我们将定义细胞信号传导如何调节DLP1和MFN活性以随后改变肝细胞线粒体的形式和功能。从这些研究中收集的信息将大大增加我们对线粒体形状和数量如何受到调节的理解，并有助于肝细胞生理和健康和疾病的损伤。