Role of Cell Adhesion in Organizing Membrane Growth

细胞粘附在组织膜生长中的作用

• 批准号: 6826010
• 负责人: Charles A Yeaman
• 金额: $ 25.81万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6826010
• 关键词: binding sites; biological signal transduction; biological transport; cell adhesion; cell cell interaction; cellular polarity; conformation; exocytosis; immunoprecipitation; plasmids; protein protein interaction; transfection; vesicle /vacuole

DESCRIPTION (provided by applicant): The long-term goal of this proposal is to understand the molecular mechanisms that regulate exocytosis in order to comprehend and develop therapies for devastating human diseases in which exocytosis is defective, such as diabetes and polycystic kidney disease. The overall objective of this work is to dissect the spatio-temporal regulation of exocytosis at a molecular level during development of epithelial cell polarity. This proposal focuses on three components of the trafficking machinery: the Exocyst (a putative vesicle tethering factor), Munc18c (a regulator of tethering/fusion machinery), and Syntaxin 4 (a component of the fusion machinery). Based upon results of preliminary studies, a working hypothesis has been developed for how polarized trafficking to the basal-lateral membrane is established. Cell-cell adhesion promotes assembly, movement and association of Exocyst with intercellular contact sites defined by E-cadherin-associated protein complexes; association of transport vesicles with these sites coincides with an interaction between an Exocyst subunit (Sec6) and Munc18c, and this in turn regulates the activity of Syntaxin 4, leading to membrane fusion. The specific aims of this study are to: 1) identify mechanisms that specify targeting patch assembly at sites of cell-cell adhesion; 2) determine the functional significance of Sec6 binding to Munc18c in basal-lateral membrane trafficking; and 3) determine whether conformational changes in Sec6 regulate its association with Munc18c. The research plan to achieve these aims involves a combination of cell biology, biochemistry and molecular biology approaches. The significance of these studies is that they will define signaling pathways and specific interactions that couple an extracellular spatial cue (cell adhesion) to organization of components involved in membrane trafficking (vesicle docking/fusion machinery) leading to establishment of cell polarity. In the long term these studies will provide new insights into understanding the basis for abnormalities in membrane protein organizations characteristic of epithelial diseases. Also, because this proposal focuses on how information is transferred from vesicle to plasma membrane to initiate exocytosis, it has broad implications for many processes including antigen presentation, neurotransmission and hormone secretion.

描述（由申请人提供）：该提案的长期目标是了解调节胞吐作用的分子机制，以便理解和开发针对胞吐作用有缺陷的毁灭性人类疾病的疗法，例如糖尿病和多囊肾病。这项工作的总体目标是在分子水平上剖析上皮细胞极性发育过程中胞吐作用的时空调节。该提案重点关注贩运机制的三个组成部分：Exocyst（一种假定的囊泡束缚因子）、Munc18c（束缚/融合机制的调节剂）和 Syntaxin 4（融合机制的组成部分）。根据初步研究的结果，对于如何建立向基底外侧膜的极化运输建立了一个工作假设。细胞间粘附促进 Exocyst 的组装、运动和与 E-钙粘蛋白相关蛋白复合物定义的细胞间接触位点的结合；运输囊泡与这些位点的关联与 Exocyst 亚基 (Sec6) 和 Munc18c 之间的相互作用相一致，这反过来又调节 Syntaxin 4 的活性，导致膜融合。 本研究的具体目的是：1）确定在细胞-细胞粘附位点靶向贴片组装的机制； 2) 确定 Sec6 与 Munc18c 结合在基底侧膜运输中的功能意义； 3) 确定 Sec6 中的构象变化是否调节其与 Munc18c 的关联。实现这些目标的研究计划涉及细胞生物学、生物化学和分子生物学方法的结合。这些研究的意义在于，它们将定义信号传导途径和特定相互作用，将细胞外空间线索（细胞粘附）与参与膜运输的组件组织（囊泡对接/融合机制）结合起来，从而导致细胞极性的建立。从长远来看，这些研究将为理解上皮疾病特征的膜蛋白组织异常的基础提供新的见解。此外，由于该提案重点关注信息如何从囊泡转移到质膜以启动胞吐作用，因此它对包括抗原呈递、神经传递和激素分泌在内的许多过程具有广泛的影响。