Molecular mechanisms of Basolateral targeting in polarized epithelial cells

极化上皮细胞基底外侧靶向的分子机制

基本信息

批准号：
7578891
负责人：
HEIKE FOLSCH
金额：
$ 26.53万
依托单位：
NORTHWESTERN UNIVERSITY
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：
2005-02-01 至 2010-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7578891
关键词：
Adaptor Signaling Protein Address Alleles Animals Apical Binding Biochemical Biochemical Genetics Biological Cell Polarity Cell membrane Cells Clathrin Adaptors Complex Connective Tissue Cytoplasmic Tail Data Defect Disease Disseminated Malignant Neoplasm Dominant-Negative Mutation Embryonic Development Endosomes Ensure Epithelial Epithelial Cells Event Face Family Genetic Goals Golgi Apparatus Grant Integral Membrane Protein Laboratories Learning Lipids Location Mediating Membrane Membrane Protein Traffic Membrane Proteins Molecular Molecular Target Monomeric GTP-Binding Proteins Names Organ Pathway interactions Play Process Proteins Recycling Regulation Role Signal Transduction Site Sorting - Cell Movement Staining method Stains Surface Testing Tissues Transcription Factor AP-1 Vesicle Work apical membrane base basolateral membrane cancer cell interest monolayer overexpression protein protein interaction receptor trans-Golgi Network vesicular stomatitis virus G protein

项目摘要

DESCRIPTION (provided by applicant): Epithelial cells are polarized into distinct apical and basolateral plasma membrane domains. The apical membrane faces the outside of the body and the basolateral membrane is in contact with connective tissues. During the lifetime of any given epithelial cell it is crucial for organ function that this established polarity is maintained. For example, loss of polarity enables a cell to disintegrate from a monolayer, which is an early step in metastatic cancer. Apical and basolateral plasma membrane domains have distinct sets of lipids and plasma membrane receptors. To maintain this distinct distribution, the cells continuously need to sort newly synthesized proteins along the biosynthetic pathway and recycle internalized receptors to the correct membrane. Basolateral targeting often depends on targeting determinants in the cytoplasmic tail of a transmembrane protein and cytosolic adaptor molecules that recognize them and mediate sorting. We identified one major cytosolic component, the clathrin-adaptor complex AP-1B (Folsch et al., 1999). Clathrin adaptor complexes are tetraheteromers. Typically the medium subunit interacts directly with the sorting signals and is therefore of particular interest. The medium subunit of AP-1B, mu1B is exclusively expressed in epithelial tissues and directly interacts with basolateral cargo molecules (Folsch et al., 2001). Our work will focus on defining the molecular mechanisms of AP-1B function and its site(s) of action. Moreover, we will analyze how the membrane recruitment of AP-1B is regulated. Furthermore, we will investigate the molecular interactions leading to AP-1B mediated basolateral targeting. My laboratory will combine cell biological, biochemical and genetic approaches to resolve the following specific aims: 1) At which intracellular site(s) does AP-1B fulfill its sorting function? 2) How is AP-1B membrane recruitment and vesicle formation regulated? 3) What is the molecular basis for AP-1B specific sorting events? A better understanding of the processes by which epithelial cells maintain polarity is essential, if we want to learn which defects in molecular sorting may transform epithelial cells into cancer cells, to name only one example of diseases associated with the loss of cell polarity.

描述（由申请人提供）：上皮细胞偏振分为不同的顶端和基底外侧质膜结构域。顶部膜面部面向人体的外部，基底外侧膜与结缔组织接触。在任何给定上皮细胞的生命周期中，对器官功能至关重要，即保持这种已建立的极性。例如，极性丧失使细胞从单层分解，这是转移性癌症的早期一步。顶端和基底外侧质膜结构域具有不同的脂质和质膜受体。为了维持这种独特的分布，细胞需要连续分类沿生物合成途径的新合成蛋白，并将内部化受体回收到正确的膜。基底外侧靶向通常取决于靶向决定因素的跨膜蛋白和胞质衔接子分子的细胞质尾部，这些分子识别它们并介导分类。我们确定了一个主要的胞质成分，即网状蛋白 - 适应器复合物AP-1B（Folsch等，1999）。网格蛋白适配器复合物是四位表。通常，培养基亚基与分类信号直接相互作用，因此特别感兴趣。 AP-1B，MU1B的培养基亚基仅在上皮组织中表达，并直接与基底外侧货物分子相互作用（Folsch等，2001）。我们的工作将集中于定义AP-1B功能的分子机制及其作用位点。此外，我们将分析如何调节AP-1B的膜募集。此外，我们将研究导致AP-1B介导的基底外侧靶向的分子相互作用。我的实验室将结合细胞生物学，生化和遗传方法来解决以下特定目的： 1）AP-1B在哪个细胞内部位履行其排序功能？ 2）如何调节AP-1B膜募集和囊泡形成？ 3）AP-1B特定分类事件的分子基础是什么？更好地理解上皮细胞维持极性的过程至关重要，如果我们想学习分子排序中的哪些缺陷可能会将上皮细胞转化为癌细胞，仅举一个与细胞极性丧失相关的疾病的例子。