Control of Epithelial Polarity

上皮极性的控制

• 批准号: 8705503
• 负责人: Keith E Mostov
• 金额: $ 33.6万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8705503
• 关键词: 3-Dimensional; Abbreviations; Adhesives; Annexins; Apical; Basement membrane; Binding; Canis familiaris; Cell Line; Cell membrane; Cells; Cellular biology; Charge; Collagen; Cyst; Data; Development; Enzymes; Epithelial; Epithelial Cells; Extracellular Matrix; Face; Gel; Hepatocyte Growth Factor; Image; Ions; Kidney; Life; Lipids; MDCK cell; Membrane; Mesenchymal; Microscopy; Modeling; Molecular; Molecular Models; Movement; Nephrons; Organ; PH Domain; PTEN gene; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipase D; Phosphoric Monoester Hydrolases; Phosphotransferases; Polycystic Kidney Diseases; Polymeric Immunoglobulin Receptors; Positioning Attribute; Protein Isoforms; Proteins; RNA Interference; Recruitment Activity; Role; Scaffolding Protein; Signal Transduction; Surface; Testing; Thin Layer Chromatography; Tight Junctions; Tube; Work; base; cellular imaging; inhibitor/antagonist; innovation; inorganic phosphate; inositol 4,5-bisphosphate; inositol 4-phosphate; inositol-1,4,5-trisphosphate 5-phosphatase; matrigel; molecular modeling; monolayer; phosphatidylinositol 3,4,5-triphosphate; podocalyxin; prevent; protein transport; research study; sialomucin; sialomucins; sodium-hydrogen exchanger regulatory factor; src Homology Region 2 Domain

DESCRIPTION (provided by applicant): Many internal organs, such as the kidney, consist of hollow tubules and spheres lined by a layer of polarized epithelial cells. These cells have an apical plasma membrane domain facing the central lumen and a basolateral plasma membrane facing the underlying basement membrane. These two plasma membrane domains have completely different protein and lipid compositions, and trafficking of proteins and lipids to these distinct membrane surfaces is vital. We have found that the signaling lipid phosphatidyl inositol 3,4,5- trisphosphate (PIP3) is found only at the basolateral plasma membrane and is a key determinant of the identity and formation of this surface. In contrast phosphatidyl inositol 4,5-bisphosphate (PIP2) is concentrated at the apical plasma membrane, where it is a main determinant of this surface. We will test the hypothesis that PIP2 and PIP3 control the development of epithelial polarity, using live cell imaging. We will test the hypothesis that PIP3 is synthesized at the basolateral plasma membrane by a specific isoform(s) of phosphatidyl inositiol 3- kinase. We will test the respective roles of the lipid phosphatases PTEN and SHIP1/2 in preventing PIP3 from accumulating at the apical plasma membrane. We will test the hypothesis that gp135/podocalyxin and proteins with which it interacts are directly involved in formation of the apical surface. Gp135 is a negatively charged, transmembrane sialomucin, which binds via a PDZ motif at its C-terminus to the scaffolding protein NHERF1. We will mislocalize gp135 to the basolateral surface and see if NHERF1 and other proteins follow. Much of the PIP2 at the plasma membrane is synthesized by phosphatidyl inositol 4- phosphate 5-kinase (PI5K). The isoform PI5K1beta is found at the apical plasma membrane and interacts with NHERF1. We will test the involvement of PI5K1beta (as well as the alpha and gamma isoforms) in formation of the apical plasma membrane. We will also test if PTEN is recruited to the apical plasma membrane by its interaction with NHERF. Together, these experiments will help us understand the molecular mechanism of apical plasma membrane and lumen formation.

描述(申请人提供)：许多内部器官，如肾脏，由中空的小管和球体组成，内衬一层极化的上皮细胞。这些细胞具有顶端质膜区和基底侧质膜，顶端质膜区面向中央管腔，基底侧质膜面向基底膜。这两个质膜结构域具有完全不同的蛋白质和脂类组成，蛋白质和脂类向这两个不同的膜表面运输是至关重要的。我们发现，信号脂质磷脂酰肌醇3，4，5-三磷酸(PIP3)只存在于基侧质膜上，是决定该表面的特性和形成的关键因素。相反，磷脂酰肌醇4，5-二磷酸(PIP2)集中在顶端质膜，在那里它是这一表面的主要决定因素。我们将使用活细胞成像来验证PIP2和PIP3控制上皮极性发展的假设。我们将验证这一假设，即PIP3是通过磷脂酰肌醇3-激酶的一个特定亚型(S)在基底侧质膜上合成的。我们将测试脂肪磷酸酶PTEN和SHIP1/2在防止PIP3在顶端质膜积聚中的各自作用。我们将检验这一假设，即gp135/podocalyin及其相互作用的蛋白质直接参与顶面的形成。Gp135是一种带负电荷的跨膜唾液酸粘蛋白，它通过其C-末端的PDZ基序与支架蛋白NHERF1结合。我们将gp135错误定位到基底侧面，看看NHERF1和其他蛋白质是否紧随其后。质膜上的PIP2大部分是由磷脂酰肌醇4-磷酸5-激酶(PI5K)合成的。异构体PI5K1β位于顶端质膜，与NHERF1相互作用。我们将测试PI5K1β(以及α和伽马异构体)在顶端质膜形成中的参与。我们还将测试PTEN是否通过与NHERF的相互作用被招募到顶端质膜。综上所述，这些实验将有助于我们了解顶端质膜和管腔形成的分子机制。