論文

査読有り
2014年7月

Single-molecule imaging and kinetic analysis of cooperative cofilin-actin filament interactions

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
  • Kimihide Hayakawa
  • ,
  • Shotaro Sakakibara
  • ,
  • Masahiro Sokabe
  • ,
  • Hitoshi Tatsumi

111
27
開始ページ
9810
終了ページ
9815
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1073/pnas.1321451111
出版者・発行元
NATL ACAD SCIENCES

The actin filament-severing protein actin depolymerizing factor (ADF)/cofilin is ubiquitously distributed among eukaryotes and modulates actin dynamics. The cooperative binding of cofilin to actin filaments is crucial for the concentration-dependent unconventional modulation of actin dynamics by cofilin. In this study, the kinetic parameters associated with the cooperative binding of cofilin to actin filaments were directly evaluated using a single-molecule imaging technique. The on-rate of cofilin binding to the actin filament was estimated to be 0.06 mu M-1.s(-1) when the cofilin concentration was in the range of 30 nM to 1 mu M. A dwell time histogram of cofilin bindings decays exponentially to give an off-rate of 0.6 s(-1). During long-term cofilin binding events (>0.4 s), additional cofilin bindings were observed in the vicinity of the initial binding site. The on-rate for these events was 2.3-fold higher than that for noncontiguous bindings. Super-high-resolution image analysis of the cofilin binding location showed that the on-rate enhancement occurred within 65 nm of the original binding event. By contrast, the cofilin off-rate was not affected by the presence of prebound cofilin. Neither decreasing the temperature nor increasing the viscosity of the test solution altered the on-rates, off-rates, or the cooperative parameter (omega) of the binding. These results indicate that cofilin binding enhances additional cofilin binding in the vicinity of the initial binding site (ca. 24 subunits), but it does not affect the off-rate, which could be the molecular mechanism of the cooperative binding of cofilin to actin filaments.

リンク情報
DOI
https://doi.org/10.1073/pnas.1321451111
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000338514800034&DestApp=WOS_CPL
ID情報
  • DOI : 10.1073/pnas.1321451111
  • ISSN : 0027-8424
  • Web of Science ID : WOS:000338514800034

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