Allosteric regulation by cooperative conformational changes of actin filaments drives mutually exclusive binding with cofilin and myosin

Kien Xuan Ngo, Nobuhisa Umeki, Saku T. Kijima, Noriyuki Kodera, Hiroaki Ueno, Nozomi Furutani-Umezu, Jun Nakajima, Taro Q.P. Noguchi, Akira Nagasaki, Kiyotaka Tokuraku, Taro Q.P. Uyeda*

*この研究の対応する著者

研究成果: Article査読

28 被引用数 (Scopus)

抄録

Heavy meromyosin (HMM) of myosin II and cofilin each binds to actin filaments cooperatively and forms clusters along the filaments, but it is unknown whether the two cooperative bindings are correlated and what physiological roles they have. Fluorescence microscopy demonstrated that HMM-GFP and cofilin-mCherry each bound cooperatively to different parts of actin filaments when they were added simultaneously in 0.2 μM ATP, indicating that the two cooperative bindings are mutually exclusive. In 0.1 mM ATP, the motor domain of myosin (S1) strongly inhibited the formation of cofilin clusters along actin filaments. Under this condition, most actin protomers were unoccupied by S1 at any given moment, suggesting that transiently bound S1 alters the structure of actin filaments cooperatively and/or persistently to inhibit cofilin binding. Consistently, cosedimentation experiments using copolymers of actin and actin-S1 fusion protein demonstrated that the fusion protein affects the neighboring actin protomers, reducing their affinity for cofilin. In reciprocal experiments, cofilin-actin fusion protein reduced the affinity of neighboring actin protomers for S1. Thus, allosteric regulation by cooperative conformational changes of actin filaments contributes to mutually exclusive cooperative binding of myosin II and cofilin to actin filaments, and presumably to the differential localization of both proteins in cells.

本文言語English
論文番号35449
ジャーナルScientific reports
6
DOI
出版ステータスPublished - 2016 10月 20

ASJC Scopus subject areas

  • 一般

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