MOLECULAR MECHANISMS OF MECHANOSENSITIVITY

机械敏感性的分子机制

• 批准号: 2082253
• 负责人: OWEN P HAMILL
• 金额: $ 27.61万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-04-01 至 1998-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2082253
• 关键词: Gastropoda; Xenopus oocyte; biomechanics; cations; cytoskeletal proteins; dystrophin; membrane channels; molecular biology; neurons; receptor sensitivity; sensory mechanism; voltage /patch clamp

DESCRIPTION: The long term goal of this project is to understand the molecular mechanisms underlying the fundamental physiological process of mechano-electrical transduction. The main focus of the proposal is on the dynamic properties (i.e., latency of response, turn on, turn off and adaptation) of MS membrane ion channels. These properties not only relate to the varied physiological roles of this channel, but also provide insight into the underlying gating mechanism. Two broad classes of MS gating mechanisms have been recognized; namely, direct and indirect. This classification is made according to how mechanical energy is coupled to the gating mechanism. The pressure-clamp/patch- clamp technique provides the opportunity to carry out rapid relaxation/perturbation measurements necessary to determine such dynamic properties as response latencies and thereby provide one means to distinguish between the two classes of mechanisms. A major experimental effort will be to characterize and compare the dynamic properties of the MS cation nonselective channel in Xenopus oocytes and the MS K+ selective channel in snail neurons. The investigators will determine if these channels are representative of the two classes. MS channels have also been classified as stretch activated (SA) and stretch inactivated (SI) according to whether mechanical gating opens or closes the channel. However, a complication in this classification is that SA channels also adapt (i.e., appear to inactivate) in the presence of maintained mechanical stimulation. One aim of this proposal will be to determine whether a common mechanism can explain the apparently opposite gating of SA and SI channels. Another aim of this proposal is to identify the role of the cytoskeleton in MS channel gating and the implication that this has in regard to patch-clamp recording. This aspect will be studied by investigating the effects of specific cytoskeletal protein disrupting and stabilizing agents on dynamic MS channel properties. The possible role of the cytoskeletal protein dystrophin in MS channel gating will be determined by comparing results obtained from control and dystrophic (mdx) mouse muscle. To resolve a recent controversy concerning the significance of MS channels measured in snail neurons with patch clamp, the relationship between MS channel currents measured in the patch and whole cell MS currents will be determined to test whether MS channels underlie whole cell MS responses. The results of this study will provide insight into the physiological and possible pathological roles of MS channels in cell function.

描述：该项目的长期目标是了解 分子机制是基本生理过程的基础 机械电气转导。 提案的主要重点是 动态属性（即响应的延迟，打开，关闭和 MS膜离子通道的适应）。 这些属性不仅 与该渠道的生理作用不同，但也是如此 提供有关潜在门控机制的洞察力。 两个广泛的课程 MS门控机制已得到认可；即直接和 间接。 根据机械方式进行此分类 能量与门控机制耦合。 压力夹/贴片 - 夹具技术提供了快速执行的机会 确定这种动态所需的放松/扰动测量 属性作为响应潜伏期，从而提供一种方式 区分两类机制。 一个主要的实验 精力将表征和比较 Xenopus卵母细胞和MS K+的MS阳离子非选择性通道 蜗牛神经元中的选择性通道。 调查人员将确定是否 这些渠道代表了这两个类别。 MS频道具有 也被归类为拉伸激活（SA）并脱位灭活 （SI）根据机械门控是打开还是关闭通道。 但是，此分类的并发症是SA频道 在存在的情况下适应（即，似乎失活） 机械刺激。 该提议的目的是确定 通用机制是否可以解释明显相反的门控 SA和SI通道。 该建议的另一个目的是确定 细胞骨架在MS通道门控的作用及其含义 这具有贴片钳记录。这方面将被研究 通过研究特定细胞骨架蛋白破坏的影响 并稳定在动态MS通道性能上。 可能 细胞骨架蛋白肌营养不良蛋白在MS通道门控的作用将 通过比较从对照和营养不良获得的结果来确定 （MDX）小鼠肌肉。解决有关该问题的最新争议 用斑块夹在蜗牛神经元中测得的MS通道的重要性， 在补丁中测得的MS通道电流之间的关系 将确定全电池MS电流以测试MS通道是否 全细胞MS响应是基础。 这项研究的结果将 提供有关生理和可能的病理作用的见解 细胞功能中的MS通道。