ELECTRICAL PROPERTIES OF TRIADS/DIADS IN STRIATED MUSCLE

横纹肌中三元组/二元组的电特性

基本信息

批准号：
3397617
负责人：
WILLIAM F GILLY
金额：
$ 15.51万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1981
资助国家：
美国
起止时间：
1981-07-01 至 1993-05-31
项目状态：
已结题

项目摘要

This proposal serves the broad, long-term objective of providing insight into common molecular mechanisms underlying i) excitation-contraction (E-C) coupling in muscle, ii) voltage controlled gating of ion channels in nerve and muscle cells, and iii) cell biological control of functional diversity in adult and developing neuromuscular systems. An integrated experimental approach will utilize three model systems: 1. Calcium channel gating in arthropod muscle. Ionic currents through Ca channels and gating currents controlling channel activation will be studied with voltage clamp techniques. Kinetic and pharmacologic analysis will advance understanding for Ca channel gating and its functional and molecular relationships to E- C coupling in skeletal muscle and to NA channel gating in neurons and muscle cells. 2. E-C coupling, charge movement and ion channels in developing vertebrate muscle. Myogenic cells form two waves (embryonic vs fetal) of avian muscle developemnt will be studied in vitro. Myotubes formed from cells of these time frames differ in morphological and biochemical parameters, but physiological differences remain unknown. Patch voltage clamp and video microscopy techniques will be used to characterize ion channels, voltage-dependent charge movement E-C coupling, and contractile properties in myotubes of each type. Embryonic myotubes which express distinct myosing heavy chains (fast and slow) will also be studied with this methodology and later identified immunocytochemically to correlate myosin-type and physiological properties. A smiilar approach will be applied to fast fetal myotubes which cna be induced to express slow myosin and to satellite cell-derived myotubes from injured adult muscle. This project will fill in several outstanding gaps in our knowledge of muscle cell developmental biology. 3. Cell biology of Na and Ca channels in neurons. Knowledge of biosynthesis and processing of membrane proteins classified as Na channels, Ca channels and voltage-sensors for E-C coupling is very limited, but primary sequence homologies in these proteins show that some relation between them exists. Proposed experiments on cultured neurons will explore the possibility that cell biological control processes can alter properties of these proteins in physiologically definable ways. Such processes must be vital in maintaining normal cellular properties and in establishing these during development (e.g., in myotubes) or recovery from injury. Studies of Na channels in cultured squid neurons following axotomy suggest that newly synthesized NA channels may have an unusual set of properties that makes the labels of Na and Ca channel ambiguous. Patch clamp studies in this system will extend these observations which are relevant to fundamental problems in neurobiology.

该提案是提供广泛的长期目标深入了解i的常见分子机制）肌肉中的激发 - 收缩（E-C）耦合，ii）电压神经和肌肉细胞中离子通道的控制门控，以及 iii）成人功能多样性的细胞生物控制和开发神经肌肉系统。集成的实验方法将利用三个模型系统： 1。节肢动物肌肉中的钙通道门控。离子电流通过CA通道和控制通道的门控电流将使用电压夹技术研究激活。动力学药理学分析将提高对CA的理解通道门控及其与E-的功能和分子关系 c在骨骼肌和神经元中的NA通道门控耦合和肌肉细胞。 2。E-C耦合，电荷运动和离子通道的发展脊椎动物肌肉。肌原细胞形成两个波（胚胎与将在体外研究鸟类肌肉发育的胎儿。这些时间框架的单元格形成的肌管不同形态学和生化参数，但生理差异仍然未知。补丁电压夹和视频显微镜技术将用于表征离子通道，电压依赖电荷运动E-C耦合，并且每种类型的肌管中的收缩特性。胚胎肌管表达明显的肌链链（快速和缓慢）也将通过这种方法研究和后来以免疫细胞化学识别以相关的肌球蛋白类型和生理特性。将采用Smiilar方法快速诱导CNA表达慢速的胎儿肌管肌球蛋白和卫星细胞衍生的肌管受伤成人肌肉。这个项目将填补我们的几个未出色的空白了解肌肉细胞发育生物学。 3。神经元中Na和Ca通道的细胞生物学。知识分类为NA的膜蛋白的生物合成和加工用于E-C耦合的通道，CA通道和电压传感器为这些蛋白质非常有限，但主要的序列同源性证明它们之间存在一些关系。建议的关于培养神经元的实验将探讨细胞生物控制过程可以改变这些的特性蛋白质在生理上可确定的方式。这样的过程必须对于维持正常的细胞特性和中至关重要在开发过程中建立这些（例如，在Myotubes中）或从伤害中恢复。培养鱿鱼中NA通道的研究轴切开后神经元表明新合成的Na 渠道可能具有一套不寻常的属性，使 NA和CA通道的标签模棱两可。斑块夹研究该系统将扩展这些观察结果神经生物学的基本问题。