Single molecule imaging and kinetic analysis of actin filament-cofilin interactions modulated by fluctuations of the actin filament.

• Project/Area Number: 24657130
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Cell biology
• Research Institution: Nagoya University
• Principal Investigator: HAYAKAWA Kimihide 名古屋大学, 医学(系)研究科(研究院), 特任講師 (60467280)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Project Status: Completed (Fiscal Year 2014)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2014: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2013: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2012: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
• Keywords: アクチン / コフィリン / 張力 / ゆらぎ / 協同性 / 力学受容 / 力覚受容 / 一分子イメージング

Outline of Final Research Achievements

Actin-depolymerizing factor/cofilin proteins preferentially sever actin filaments when the filament was not tensed. We performed real-time single molecule imaging of the binding of cofilin to single actin filaments without tension. Our results show that the binding of a single cofilin molecule enhances the binding of additional cofilin within 65 nm (across 26 actin protomers) of the initial binding site. The fluctuations of the actin filaments was positively correlated to the on-rate of cofilin binding.

Research Products

• [Journal Article] Single-molecule imaging and kinetic analysis of cooperative cofilin-actin filament interactions. (2014)
  • Author(s): Kimihide Hayakawa, Shotaro Sakakibara, Masahiro Sokabe, Hitoshi Tatsumi
  • Journal Title: Proceedings of the National Academy of Science of the United States of America Volume: 111 (27) Issue: 27 Pages: 9810-9815
  • DOI: 10.1073/pnas.1321451111
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Presentation] ATPおよびADP結合アクチンフィラメントに対するコフィリン結合の一分子観察 (2014)
  • Author(s): 早川公英、曽我部正博、辰巳仁史
  • Organizer: 第52回日本生物物理学会年会
  • Place of Presentation: 札幌コンベンションセンター（札幌市）
  • Year and Date: 2014-09-25 – 2014-09-27
• [Presentation] アクチン繊維による力覚受容 “Mechano-sensing” by actin filaments. (2014)
  • Author(s): 早川公英、辰巳仁史、曽我部正博
  • Organizer: 第53回日本生体医工学会大会
  • Place of Presentation: 仙台コンベンションセンター（仙台市）
  • Year and Date: 2014-06-26
  • Invited
• [Presentation] “Mechano-sensing” by actin filaments. (2014)
  • Author(s): Kimihide Hayakawa, Masahiro Sokabe, Hitoshi Tatsumi
  • Organizer: INTERNATIONAL SYNPOSIOUM ON MECHANOBIOLOGY 2014
  • Place of Presentation: 岡山大学(岡山市）
  • Year and Date: 2014-05-21
• [Presentation] Direct measurement of thermodynamic parameters of cofilin-actin filament interactions at the single molecule level. (2014)
  • Author(s): 早川公英、榊原正太郎、曽我部正博、辰巳仁志
  • Organizer: Biophysical Society
  • Place of Presentation: San Francisco, USA
• [Presentation] Analysis of Cooperative Cofilin-Actin Filament Interactions examined at the single molecule level. (2013)
  • Author(s): 早川公英、榊原正太郎、曽我部正博、辰巳仁志
  • Organizer: 日本生物物理学会
  • Place of Presentation: 京都国際会議場、京都
• [Presentation] Direct observation of cooperative binding of cofilin to actin filaments (2012)
  • Author(s): Kimihide Hayakawa, Hitoshi Tatsumi, Takahumi Goto, Masahiro Sokabe
  • Organizer: 日本生物物理学会第50回年会
  • Place of Presentation: 名古屋大学
• [Presentation] A theoretical model of cooperative binding of cofilin to actin filaments (2012)
  • Author(s): Shota Sakakibara, Kimihide Hayakawa, Hitoshi Tatsumi, Masahiro Sokabe
  • Organizer: 日本生物物理学会第50回年会
  • Place of Presentation: 名古屋大学