Role of myosin 1e in podocyte biology and renal filtration

描述(申请人提供)：为了改善慢性肾脏疾病的预防和治疗，慢性肾脏疾病是美国和世界范围内的一个主要公共卫生问题，识别正常肾小球功能所需的蛋白质是至关重要的。识别对肾小球滤过至关重要的蛋白质将有助于准确定位导致肾功能障碍的疾病途径的分子靶点。这项研究的目标是确定肌动蛋白依赖的分子马达肌球蛋白1e(Myo1e)在正常肾功能和肾脏疾病发展中的作用。肌球蛋白1e表达于肾小球足细胞，这是一种特殊的肾上皮细胞，在选择性肾滤过中起关键作用。我们发现，myo1e基因敲除的小鼠是存活的，但在肾小球滤过和组织方面存在严重缺陷。本项目的重点是鉴定足细胞中myo1e的细胞内功能，并分析myo1e在维持正常肾滤过中的作用。这些研究将有助于确定肌电活动的变化如何有助于肾脏疾病的进展。我们提出了一种假说，即肌动活动是其在正常足细胞功能中所必需的。为了验证这一假设，我们将追求以下具体目标。目的1.分析足细胞中myo1e基因突变对其功能的影响。在这一目标中，我们将确定肌肉运动活动在足细胞迁移和细胞形状调节中的作用。目的2.确定足细胞内的信号通路是如何受到肌电活动丧失的影响的，并分析足细胞信号对肌电功能的调节。目的3.检测myo1e突变体对缺失myo1e小鼠肾小球滤过功能缺陷的修复能力。

DESCRIPTION (provided by applicant): In order to improve prevention and treatment of chronic kidney disease, a major public health concern in the US and worldwide, it is essential to identify proteins that are necessary for normal glomerular functions. Identification of proteins that are critical for glomerular filtration will help pinpoint molecular targets of disease pathways that lead to renal dysfunction. The goal of this research project is to identify the roles of an actin-dependent molecular motor myosin 1e (myo1e) in normal kidney functions and in development of kidney disease. Myosin 1e is expressed in glomerular podocytes, specialized kidney epithelial cells that play a critical role in selective renal filtration. We have found that myo1e knockout mice are viable but exhibit severe defects in glomerular filtration and organization. This project focuses on identification of the intracellular functions of myo1e in podocytes and analysis of the role of myo1e in maintaining normal renal filtration. These studies will help determine how changes in myo1e activity may contribute to progression of kidney disease. We propose a hypothesis that myo1e motor activity is required for its role in normal podocyte functions. In order to test this hypothesis, we will pursue the following specific aims. Aim 1. Analyze the effects of mutations in myo1e on its functions in podocytes. In this aim we will determine the role of myo1e motor activity in regulation of podocyte migration and cell shape. Aim 2. Determine how intracellular signaling pathways in podocytes are affected by the loss of myo1e activity and analyze regulation of myo1e motor functions by podocyte signaling. Aim 3. Test the ability of myo1e mutants to rescue the defects in glomerular filtration in mice lacking myo1e.