Gap Junction Trafficking to and within the Plasma Membrane

间隙连接运输到质膜和质膜内

• 批准号: 8443871
• 负责人: Robin M Shaw
• 金额: $ 1.92万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-15 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8443871
• 关键词: Actins; Affect; Arrhythmia; Behavior; Binding; Biochemistry; Blood flow; Cardiac; Cardiac Myocytes; Cell membrane; Cells; Cellular biology; Clinical; Congestive Heart Failure; Connexin 43; Connexon; Coupling; Cytoskeleton; Data; Diffuse; Diffusion; Disease; Elements; Event; Fluorescence Microscopy; Functional disorder; Future; Gap Junctions; Goals; Growth; Health; Heart failure; Imaging Techniques; Imaging technology; Intercalated disc; Ion Channel; Ischemia; Knowledge; Laboratories; Lateral; Life; Location; Measures; Membrane; Microtubules; Molecular; Morbidity - disease rate; Movement; Myocardial Ischemia; Oxidative Stress; Pattern; Positioning Attribute; Process; Property; Proteins; Regulation; Resolution; Role; Simulate; Stress; Sudden Death; Techniques; Testing; Time; United States; Ventricular; Work; base; cellular imaging; charge coupled device camera; fluorescence imaging; heart cell; immunocytochemistry; inhibitor/antagonist; mortality; prevent; protein transport; sudden cardiac death; targeted delivery; therapeutic target; therapy development; trafficking

DESCRIPTION (provided by applicant): Ischemic heart disease and its associated complications of sudden cardiac death and congestive heart failure remain leading causes of morbidity and mortality in the United States. The arrhythmogenic pathophysiology of ischemic disease includes loss of cardiomyocyte electrical coupling through altered localization and modulation of gap junctions. The precise molecular mechanisms underlying altered coupling remain elusive. The objective of this proposal is to understand the cellular movement of gap junction hemichannels (connexons) in normal and ischemic conditions. Our central hypothesis is that connexons require the cytoskeleton to target them to specific locations on the plasma membrane and, once in the plasma membrane, there is a limited role of lateral diffusion and other means of non- cytoskeleton based channel movement. The hypothesis will be tested by using fixed and live cell imaging techniques including high resolution total internal reflection fluorescence (TIRF) imaging, with supplementary biochemistry, to understand the molecular mechanisms of connexon trafficking. Particular aims include understanding the role of microtubule based directed targeting of connexons to intercalated discs in conditions of oxidative stress and simulated ischemia; to understand the role of the actin cytoskeleton in targeted delivery of connexons; and to determine quantitatively the capacity of connexons to diffuse laterally to other membrane regions within the plasma membrane. Preliminary data indicate that oxidative stress limits microtubule capture of cortical membrane, preventing delivery of connexons to the plasma membrane; that actin helps microtubules position and target ion channels to specific regions of the cortical membrane, and that lateral diffusion of connexons is highly restricted. These aims will further our understanding of the regulation and behavior of cardiac gap junctions. The general field of protein trafficking will benefit from fundamental new knowledge about cytoskeleton and ischemic type regulation of these channels. Furthermore, key molecules and events in the trafficking of gap junctions will be identified to be used as therapeutic targets to lessen the arrhythmias and dysfunction associated with ischemic heart disease.

描述（由申请人提供）：缺血性心脏病及其心源性猝死和充血性心力衰竭的相关并发症仍然是美国发病率和死亡率的主要原因。缺血性疾病的致心律失常病理生理学包括通过改变间隙连接的定位和调节而导致心肌细胞电耦合丧失。改变耦合背后的精确分子机制仍然难以捉摸。该提案的目的是了解间隙连接半通道（连接子）在正常和缺血条件下的细胞运动。我们的中心假设是连接子需要细胞骨架将它们靶向质膜上的特定位置，并且一旦进入质膜，横向扩散和其他基于非细胞骨架的通道运动的作用就有限。该假设将通过使用固定和活细胞成像技术（包括高分辨率全内反射荧光（TIRF）成像）和补充生物化学来测试，以了解连接子运输的分子机制。具体目标包括了解基于微管的连接子定向靶向闰盘在氧化应激和模拟缺血条件下的作用；了解肌动蛋白细胞骨架在连接子靶向递送中的作用；并定量确定连接子横向扩散到质膜内其他膜区域的能力。初步数据表明，氧化应激限制了皮质膜的微管捕获，阻止了连接子向质膜的传递；肌动蛋白帮助微管将离子通道定位和靶向皮质膜的特定区域，并且连接子的横向扩散受到高度限制。这些目标将进一步加深我们对心脏间隙连接的调节和行为的理解。蛋白质运输的一般领域将受益于有关细胞骨架和这些通道的缺血型调节的基本新知识。此外，间隙连接运输中的关键分子和事件将被确定用作治疗靶点，以减轻与缺血性心脏病相关的心律失常和功能障碍。