Exploring the mechanical behavior of single intermediate filaments
Exploring the mechanical behavior of single intermediate filaments
复制标题
DOI：
10.1016/j.jmb.2005.09.092
复制
发表时间：
2005-12-02
影响因子：
5.6
通讯作者：
Aebi, U
中科院分区：
文献类型：
--
作者：
Kreplak, L;Bär, H;Aebi, U
中间纤维是真核细胞的结构元素，具有独特的力学性能。当IF缺失或由于突变导致功能障碍时，组织完整性会受到严重损害，尤其是皮肤和肌肉。我们对IF力学性能的了解主要基于宏观纤维的拉伸测试和IF网络的流变性。在单丝水平上，唯一可用的数据是波形蛋白IF的持续长度。在这里，我们使用了一种基于原子力显微镜(AFM)的协议来直接探测单个细胞质IF在生理缓冲环境中吸附到固体载体上时的力学性质。在体外研究了三种IF类型：重组小鼠结蛋白、重组人角蛋白K5/K14和从大鼠脑中分离的神经丝，它们由神经丝三联体蛋白NF-L、NF-M和NF-H组成。根据实验条件，AFM针尖被用来横向移动或拉伸吸附在其上的单个IF。在施加外力时，IF平均拉伸2.6倍。我们遇到的最大拉伸是3.6倍。随之而来的是表观细丝直径的大幅度减小。因此，观察到的力学性能表明，在体内，IFS确实可以作为机械减震器发挥作用。(C)2005爱思唯尔有限公司。保留所有权利。
Intermediate filaments (IFs) are structural elements of eukaryotic cells with distinct mechanical properties. Tissue integrity is severely impaired, in particular in skin and muscle, when IFs are either absent or malfunctioning due to Mutations. Our knowledge on the mechanical properties of IFs is mainly based on tensile testing of macroscopic fibers and on the rheology of IF networks. At the single filament level, the only piece of data available is a measure of the persistence length of vimentin IFs.Here, we have employed an atomic force microscopy (AFM) based protocol to directly probe the mechanical properties of single cytoplasmic IFs when adsorbed to a solid Support in physiological buffer environment. Three IF types were studied in vitro: recombinant murine desmin, recombinant human keratin K5/K14 and neurofilaments isolated from rat brains, which are composed of the neurofilament triplet proteins NF-L, NF-M and NF-H. Depending on the experimental conditions, the AFM tip was used to laterally displace or to stretch single IFs on the support they had been adsorbed to. Upon applying force, IFs were stretched on average 2.6-fold. The maximum stretching that we encountered was 3.6-fold. A large reduction of the apparent filament diameter was observed concomitantly. The observed mechanical properties therefore Suggest that IFs may indeed function as mechanical shock absorbers in vivo. (c) 2005 Elsevier Ltd. All rights reserved.