Crumbs3 and Epithelial Polarity

Crumbs3 和上皮极性

基本信息

批准号：
8320425
负责人：
BENJAMIN L MARGOLIS
金额：
$ 31.07万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-02-15 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8320425
关键词：
Acute Kidney Failure Apical Binding Proteins Cell Polarity Cell division Cells Complex Cytokinesis Data Development Disease Epithelial Epithelial Cells Epithelium Excision Goals Injury Integral Membrane Protein Kidney Kidney Failure Knock-in Mouse Laboratories Lateral Lead Maintenance Membrane Membrane Protein Traffic Mesenchymal Mesenchyme Modeling Movement Mus Natural regeneration Pathway interactions Phosphorylation Phosphotransferases Play Polycystic Kidney Diseases Process Protein Family Protein Isoforms Proteins RNA Splicing Recovery Regulation Renal function Role Side Signaling Molecule Tail Testing Tight Junctions Time Transforming Growth Factor beta Tube Work apical membrane basolateral membrane epithelial to mesenchymal transition in vivo in vivo Model nephrogenesis overexpression polarized cell protein complex public health relevance renal epithelium tissue culture trafficking

项目摘要

DESCRIPTION (provided by applicant): The polarization of renal epithelia is crucial for proper kidney development and function. Recent work from our laboratory and others has pointed to an important role for the Crumbs family of proteins in development and maintenance of epithelial cell polarity. Our work has focused on Crumbs3 which is the predominant form in renal epithelia. Crumbs3 is a small apical transmembrane protein that exists as two different splice isoforms. One isoform, Crumbs3a, uses an evolutionarily conserved carboxy-terminal tail to organize two important polarity complexes, the Crumbs/PALS/PATJ complex and the PAR3/PAR6/aPKC complex. Loss of Crumbs3 expression or overexpression of Crumbs3 can lead to a loss of cell polarity and tight junction formation. It is felt that Crumbs3 functions as a transmembrane anchor that localizes signaling molecules such as aPKC to define the apical domain via reciprocal phosphorylation steps with kinases localized on the basolateral membrane. However a fundamental question is how is Crumbs3 initially localized to instruct creation of the apical membrane. Our newest studies in three-dimensional culture demonstrate that Crumbs3 initiates apical membrane and lumen formation very early in cell division during the cytokinetic process. We hypothesize that the ability of Crumbs3 to target to the mid-body during the cytokinetic process is a crucial step in initial apical membrane and lumen formation. This hypothesis will be tested in the first specific aim where we will examine if factors that regulate membrane trafficking to the midbody during cytokinesis also regulate initial apical membrane formation. In the second specific aim, we will examine the regulation of Crumbs3 expression and trafficking in established polarized epithelia and in epithelia undergoing mesenchymal transition. The last specific aim will examine these processes in vivo by generating a GFP knock in Crumbs3 mouse. This will allow us to determine if our hypothesis generated in tissue culture models holds during kidney development, normal kidney function and during renal recovery from injury. PUBLIC HEALTH RELEVANCE: The goal of this work is to understand the steps that lead to polarized epithelia and kidney tube formation. The proposal focuses on a protein called Crumbs that is crucial in this process. Proper tube formation is important in many diseases including polycystic kidney disease and in recovery from kidney failure. Our data will delineate the basic steps utilized by the Crumbs protein to initiate epithelial polarization.

描述（由申请人提供）：肾上皮细胞的极化对于肾脏的正常发育和功能至关重要。我们实验室和其他实验室最近的工作指出了 Crumbs 蛋白家族在上皮细胞极性的发育和维持中的重要作用。我们的工作重点是 Crumbs3，它是肾上皮细胞中的主要形式。 Crumbs3 是一种小的顶端跨膜蛋白，以两种不同的剪接亚型存在。 Crumbs3a 是一种异构体，它使用进化上保守的羧基末端尾部来组织两个重要的极性复合物，即 Crumbs/PALS/PATJ 复合物和 PAR3/PAR6/aPKC 复合物。 Crumbs3 表达缺失或 Crumbs3 过度表达可导致细胞极性和紧密连接形成的丧失。据认为，Crumbs3 充当跨膜锚，定位信号分子（例如 aPKC），通过与位于基底外侧膜上的激酶的相互磷酸化步骤来定义顶端结构域。然而，一个基本问题是 Crumbs3 最初如何定位以指导顶膜的创建。我们在三维培养中的最新研究表明，Crumbs3 在细胞分裂过程中的细胞分裂早期就启动了顶膜和管腔的形成。我们假设 Crumbs3 在细胞分裂过程中靶向中体的能力是初始顶膜和管腔形成的关键步骤。这一假设将在第一个具体目标中得到检验，我们将检查在胞质分裂期间调节膜运输到中体的因素是否也调节初始顶膜形成。在第二个具体目标中，我们将检查已建立的极化上皮细胞和正在进行间质转化的上皮细胞中 Crumbs3 表达和运输的调节。最后一个具体目标是通过在 Crumbs3 小鼠中产生 GFP 敲除来在体内检查这些过程。这将使我们能够确定在组织培养模型中产生的假设在肾脏发育、正常肾功能和肾脏损伤恢复期间是否成立。公共卫生相关性：这项工作的目标是了解导致极化上皮和肾管形成的步骤。该提案的重点是一种名为 Crumbs 的蛋白质，它在此过程中至关重要。适当的管形成对于包括多囊肾病和肾衰竭的恢复在内的许多疾病都很重要。我们的数据将描述 Crumbs 蛋白启动上皮极化的基本步骤。