Secretion-associated dynamic of the plasma membrane

质膜的分泌相关动态

• 批准号: 7674348
• 负责人: Arun Anantharam
• 金额: $ 4.72万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7674348
• 关键词: Adrenal Glands; Biochemical; Biochemistry; Biogenic Amines; Biological; Cardiovascular system; Cell membrane; Cell model; Cells; Chromaffin Cells; Coupled; Cytoplasmic Granules; Detection; Development; Docking; Endocrine; Endocytosis; Event; Exocytosis; Extracellular Space; Kinetics; Left; Length; Lipids; Location; Membrane; Membrane Proteins; Molecular Conformation; Morphology; Nature; Neuroendocrine Cell; Neurons; Neuropeptides; Optical Methods; Optics; Pathway interactions; Phosphatidylinositols; Physiological; Plasma; Process; Property; Proteins; Regulation; Relative (related person); Resolution; Role; Rupture; Series; Site; Techniques; Time; Uncertainty; amphiphysin; base; cohort; design; effusion; insight; nervous system disorder; presynaptic; research study; response; synaptotagmin; treatment strategy

DESCRIPTION (provided by applicant): This proposal will fill a gap in our understanding of key events in secretion, namely, the nature of changes in plasma membrane morphology and biochemistry during the coupled processes of exocytosis and endocytosis. When triggered by Ca2+, neuroendocrine cells release biogenic amines and neuropeptides into the extracellular space through fusion of dense core granules with the plasma membrane. Granule membranes are then retrieved for reuse via endocytosis. A precisely orchestrated series of events underlie the proper execution of these tasks. Prior to exocytosis, biochemical interactions between granule and plasma membrane proteins and lipids occur priming the granule for fusion; the inositol phospholipid Pl(4,5) P2 is critical for these events. The respective membranes are then ruptured and merged to form a fusion pore. After exocytosis, other interactions occur to deform the plasma membrane and recover granule membrane constituents. In recent years, a cohort of proteins thought to be important in exo-/endocytosis has been identified. Some of these are predicted to alter membrane morphology, either prior to exocytosis, such as synaptotagmin, or after exocytosis, such as endophilin and amphiphysin. The timing and the location of these changes may be influenced by their interaction with PI(4,5)P2. There is also uncertainty about the length of time the granule membrane retains its curvature before it flattens into the plasma membrane or is retrieved by endocytosis. Because rapid, high resolution detection of plasma membrane events has been difficult, the elucidation of these processes is still lacking. The unifying hypothesis behind this proposal is that the underlying biochemical and physiological changes in the plasma membrane important for secretion result in changes of membrane conformation. The Specific Aims are designed to: 1) Determine the morphological dynamics of the plasma membrane associated with exocytosis and endocytosis; 2) Determine the role of PI(4,5)P2 in regulating properties of the plasma membrane important for secretion. The experiments will utilize adrenal chromaffin cells, and confocal and TIR-based optical methods. It is anticipated that the results of our studies will provide fundamental insights into the regulation and dynamics of the secretory response. They will also have broad relevance based on the similarity of the chromaffin cell model to other neuroendocrine cells and to presynaptic pathways in neurons. A more complete understanding of the mechanisms underlying exo-/endocytosis will help drive the development of rational strategies for the treatment of cardiovascular, endocrine and neurological diseases.

描述（由申请人提供）：该提案将填补我们对分泌关键事件的理解空白，即胞吐作用和内吞作用耦合过程中质膜形态和生物化学变化的本质。当 Ca2+ 触发时，神经内分泌细胞通过致密核心颗粒与质膜的融合将生物胺和神经肽释放到细胞外空间。然后通过内吞作用回收颗粒膜以供重复使用。一系列精心策划的事件是正确执行这些任务的基础。在胞吐作用之前，颗粒与质膜蛋白和脂质之间发生生化相互作用，引发颗粒融合；肌醇磷脂 Pl(4,5) P2 对于这些事件至关重要。然后各个膜破裂并合并形成融合孔。胞吐作用后，发生其他相互作用以使质膜变形并恢复颗粒膜成分。近年来，已经鉴定出一组被认为在外吞/内吞作用中重要的蛋白质。其中一些预计会在胞吐作用之前（例如突触结合蛋白）或在胞吐作用之后（例如内亲蛋白和两性蛋白）改变膜形态。这些变化的时间和位置可能受到它们与 PI(4,5)P2 相互作用的影响。颗粒膜在变平进入质膜或通过内吞作用恢复之前保持其曲率的时间长度也存在不确定性。由于快速、高分辨率地检测质膜事件一直很困难，因此仍然缺乏对这些过程的阐明。该提议背后的统一假设是，质膜中对分泌很重要的潜在生化和生理变化导致膜构象的变化。具体目标旨在： 1) 确定与胞吐作用和内吞作用相关的质膜形态动力学； 2) 确定 PI(4,5)P2 在调节对分泌重要的质膜特性中的作用。实验将利用肾上腺嗜铬细胞以及共聚焦和基于 TIR 的光学方法。预计我们的研究结果将为分泌反应的调节和动态提供基本见解。基于嗜铬细胞模型与其他神经内分泌细胞和神经元突触前通路的相似性，它们也将具有广泛的相关性。更全面地了解外吞/内吞作用的机制将有助于推动治疗心血管、内分泌和神经疾病的合理策略的发展。