Protein-protein interactions that make the actin filament functional

2016 Fiscal Year Final Research Report

• Project/Area Number: 26251017
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Biophysics
• Research Institution: Nagoya University
• Principal Investigator: Maeda Yuichiro 名古屋大学, 理学研究科, 特任教授 (10321811)
• Co-Investigator(Kenkyū-buntansha): 成田 哲博 名古屋大学, 理学(系)研究科(研究院), 准教授 (30360613)
• Co-Investigator(Renkei-kenkyūsha): Shuichi Takeda 名古屋大学, 理学研究科, 研究員 (50509081) ; Tomoharu Matsumoto 名古屋大学, 理学研究科, 研究員 (30392880) ; Mahito Kikumoto 名古屋大学, 理学研究科, 研究員 (20462880) ; Kayo Maeda 名古屋大学, 理学研究科, 研究員 (00321810) ; Ryotaro Koike 名古屋大学, 情報科学研究科, 助教 (20381577) ; Motonori Ota 名古屋大学, 情報科学研究科, 助教 (40290895)
• Project Period (FY): 2014-06-27 – 2017-03-31
• Keywords: 細胞運動 / 細胞骨格 / アクチン・トレッドミリング / 筋収縮の調節 / Ｘ線結晶構造解析 / クライオ電子顕微鏡法

Outline of Final Research Achievements

Cell motility is powered by the actin ATPase through the cyclic polymerization and depolymerization-driven molecular movement-of actin. Our study has been aimed at understanding the mechanism how chemical energy release by the actin ATPase reaction is transformed into physical forces. In 2009, we discovered that polymerization is associated with conformational transition of actin from G-form to F-form. In the present study, we have elucidated first atomic resolution structures (at 1.5A resolution) of F-form actin. Based on these structures, we have proposed (1) mechanisms how the G-to-F transformation induces the ATP hydrolysis, (2) reasons why the Pi release from F-form actin is slow, and (3) reasons why ADP-F-actin is less stable than ATP-F-actin or ADPPi-F-actin. The present results have opened up a new era in our understanding how the ATP hydrolysis is coupled to the process of molecular assembly-disassembly (polymerization and depolymerization) of actin.

Free Research Field

生物物理学・構造生理学