The ultrastructural basis of actin filament regulation.
The ultrastructural basis of actin filament regulation.
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肌动蛋白丝调节的超微结构基础。
DOI：
10.1007/978-3-540-46558-4_12
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发表时间：
2002
影响因子：
--
通讯作者：
Lehman,William
中科院分区：
文献类型：
--
作者：
Craig,Roger;Lehman,William
肌动蛋白丝几乎存在于所有细胞中，在整个动物和植物界中发挥着不同的功能。它们通常是动态结构，可以根据需要拆卸或重新组装。肌动蛋白通过与特定的肌动蛋白结合蛋白结合来实现这些惊人的壮举，从而改变其结构，使其能够执行所需的功能。这些肌动蛋白结合蛋白包括交联细丝（形成束或网络）、切断细丝（导致解聚）、隔离肌动蛋白单体（防止聚合）、帽丝（抑制解聚）以及充当运动蛋白以产生运动的成分。在横纹肌中，肌动蛋白丝是永久性结构，通过在 Z 线和 M 线末端加帽蛋白质来防止解聚。它们在收缩过程中执行两个关键功能：(1) 它们与肌球蛋白横桥进行循环相互作用，使肌动蛋白丝滑动穿过肌球蛋白丝，从而导致缩短和受力。(2) 在大多数横纹肌中，它们还通过打开或关闭与肌动蛋白的横桥相互作用来调节收缩，以响应胞质游离 Ca2+ 浓度的变化。大多数横纹肌的调节取决于肌动蛋白丝与肌动蛋白结合蛋白原肌球蛋白 (Tm) 的关联，而原肌球蛋白 (Tm) 又与 Ca2+ 结合蛋白复合物肌钙蛋白 (Tn) 关联。在平滑肌中，原肌球蛋白与其他肌动蛋白结合蛋白相关，可能参与调节肌动蛋白-肌球蛋白相互作用。在本章中，我们回顾了电子显微镜（EM）和图像处理对我们理解横纹肌和平滑肌肌动蛋白丝调节分子机制的贡献。我们将结果与从 X 射线衍射获得的结构数据相关联，并将结构数据的解释与基于生化和其他方法的模型联系起来。有关细丝超微结构研究的早期综合综述，请参阅 O'Brien 和 Dickens (1983)。
Actin filaments are found in virtually all cells, performing diverse functions throughout the animal and plant kingdoms. They are generally dynamic structures that may disassemble or reassemble as needed. Actin accomplishes these astonishing feats by binding to specific actin-binding proteins, which modify its structure, enabling it to perform the required function. These actin-binding proteins include components that cross-link filaments (forming bundles or networks), sever filaments (causing depolymerization), sequester actin monomers (preventing polymerization), cap filaments (inhibiting depolymerization), and those that act as motor proteins to generate motility. In striated muscle, actin filaments are permanent structures that are prevented from depolymerizing by capping proteins at both Z-line and M-line ends. They perform two crucial functions in contraction:(1) They undergo cyclic interaction with myosin crossbridges, generating sliding of the actin filaments past the myosin filaments, which leads to shortening and force.(2) In most striated muscles, they also regulate contraction, by switching crossbridge interaction with actin ON or OFF, in response to changes in cytosolic free Ca2+ concentration. Regulation in most striated muscles is dependent on association of actin filaments with the actin-binding protein, tropomyosin (Tm), which in turn is associated with the Ca2+-binding protein complex, troponin (Tn). In smooth muscles, tropomyosin is associated with other actin-binding proteins, which may be involved in modulating actin-myosin interaction.In this chapter we review the contributions of electron microscopy (EM) and image processing to our understanding of the molecular mechanism of actin filament regulation in striated and smooth muscles. We correlate the results with structural data obtained from X-ray diffraction, and we relate interpretations of structural data to models based on biochemical and other approaches. For an earlier, comprehensive review on ultrastructural studies of thin filaments, see O'Brien and Dickens (1983).
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DOI：
--
发表时间：
1993
期刊：
影响因子：
--
作者：
J. Squire;Hind A. Al;N. Yagi
通讯作者：
N. Yagi
电子显微镜对肌动蛋白副晶体研究的证据，涉及脊椎动物骨骼肌细丝中交叉条纹的起源
DOI：
--
发表时间：
1973
期刊：
Proceedings of the Royal Society of London. Series B. Biological Sciences
影响因子：
--
作者：
E. J. Hanson
通讯作者：
E. J. Hanson
影响因子：
4.8
作者：
Landis, CA;Bobkova, A;Tobacman, LS
通讯作者：
Tobacman, LS
影响因子：
5.6
作者：
HANSON, J;LOWY, J
通讯作者：
LOWY, J
第7章-钙调蛋白
DOI：
--
发表时间：
1996
期刊：
影响因子：
--
作者：
M. Gimona
通讯作者：
M. Gimona