Regulated exocytosis and endocytosis coupling in pancreatic endocrine cells

描述（由申请人提供）：该项目的长期目标是提高我们对β细胞生物学的认识，探索新的治疗策略和潜在的药物靶向治疗糖尿病。β细胞对胰岛素分泌和葡萄糖稳态至关重要。β细胞的功能障碍是糖尿病发展的关键步骤。最近的全基因组筛选发现了许多与β细胞中胰岛素颗粒膜运输相关的基因。胞吞作用是与胰岛素胞吐作用相结合的细胞膜运输的一个基本步骤。虽然胞吐过程中细胞膜和囊泡蛋白的及时回收对β细胞的结构和功能至关重要，但其潜在的分子机制仍未得到解决。动力蛋白是一种保守的内吞机制蛋白，被认为在许多形式的内吞作用中起着关键作用。然而，近年来的遗传学研究对动力素在大脑中的功能的经典观点提出了许多新的问题。不同的动力蛋白异构体可能具有不同的或冗余的功能。我们的初步数据表明，胰岛中有不止一种异构体表达，培养中动力蛋白的消融显示膜运输受损。动力蛋白可能在葡萄糖稳态、糖耐量受损和糖尿病中起重要作用。根据我们最近对脑动力蛋白的研究和目前在胰岛的初步数据，我们将研究不同的动力蛋白异构体在调节内噬作用、胰岛素分泌和葡萄糖稳态中的作用。我们将进行实时电容测量，荧光成像，使用生成β细胞特异性，诱导动力蛋白消融β细胞和小鼠模型。

DESCRIPTION (provided by applicant): The long term goal of this project is to improve our knowledge of beta cell biology and to explore new strategies of therapy and potential drug targeting to cure diabetes. Beta cells are essential for insulin secretion and glucose homeostasis. Malfunction of beta cells is a key step in the development of diabetes. Recent genome-wide screening identified numerous genes that associate with insulin granule membrane trafficking in beta cells. Endocytosis is a fundamental step of membrane trafficking that is coupled with insulin exocytosis. While this timely retrieval of membrane and vesicle proteins that are added to the cell surface during exocytosis is critical for beta cell structure and function, the underlying molecular mechanism remains unresolved. Dynamin, a conserved protein of the endocytic machinery, has been thought to serves as a pinchase in many forms of endocytosis. However, recent genetic studies raised many new questions on the classical view of dynamin function in the brain. Different dynamin isoform may have distinct or redundant functions. Our preliminary data demonstrated more than one isoforms expressed in pancreatic islets, ablation of dynamins in culture showed impaired membrane trafficking. Dynamin may play an important role in glucose homeostasis, impaired glucose tolerance and diabetes. Guided by our recent study on dynamin in the brain and current preliminary data in pancreatic islets, we will investigate the role of different dynamin isoforms in regulation of endocytosis, insulin secretion, and glucose homeostasis. We will perform real-time capacitance measurement, fluorescence imaging, using generate beta cell specific, inducible dynamin ablation beta cells and mouse models.