Mechanical unfolding of single filamin A (ABP‐280) molecules detected by atomic force microscopy

FEBS Letters

Furuike, Shou¹  Ito, Tadanao²  Yamazaki, Masahito¹ 

[1] Materials Science, Graduate School of Science and Engineering, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan;Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan

关键词: Cytoskeleton;    Actin/filamin A gel;    Mechanical unfolding;    Mechanical response of cell;    Atomic force microscopy;   

DOI  :  10.1016/S0014-5793(01)02497-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Filamin A (ABP-280), which is an actin-binding protein of 560 kDa as a dimer, can, together with actin filaments, produce an isotropic cross-linked three-dimensional network (actin/filamin A gel) that plays an important role in mechanical responses of cells in processes such as maintenance of membrane stability and translational locomotion. In this study, we investigated the mechanical properties of single filamin A molecules using atomic force microscopy. In force–extension curves, we observed sawtooth patterns corresponding to the unfolding of individual immunoglobulin (Ig)-fold domains of filamin A. At a pulling speed of 0.37 μm/s, the unfolding interval was sharply distributed around 30 nm, while the unfolding force ranged from 50 to 220 pN. This wide distribution of the unfolding force can be explained by variation in values of activation energy and the width of activation barrier of 24 Ig-fold domains of the filamin A at the unfolding transition. This unfolding can endow filamin A with great extensibility. The refolding of the unfolded chain of filamin A occurred when the force applied to the protein was reduced to near zero, indicating that its unfolding is reversible. Based on these results, we discuss here the physiological implications of the mechanical properties of single filamin A molecules.

【 授权许可】

Unknown