Mechanics of actomyosin networks beneath the cell membrane

• Project/Area Number: 16H06165
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Biophysics
• Research Institution: Kyoto University (2017-2018); Waseda University (2016)
• Principal Investigator: Miyazaki Makito 京都大学, 白眉センター, 特定准教授 (40609236)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥24,830,000 (Direct Cost: ¥19,100,000、Indirect Cost: ¥5,730,000); Fiscal Year 2018: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000); Fiscal Year 2017: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2016: ¥18,070,000 (Direct Cost: ¥13,900,000、Indirect Cost: ¥4,170,000)
• Keywords: 細胞骨格 / アクトミオシン / 分子モーター / 人工細胞 / 再構成 / 細胞運動 / 対称性の破れ / 細胞分裂 / 生物物理

Outline of Final Research Achievements

Actomyosin networks beneath the cell membrane regulate various cellular functions including cell motility and intracellular positioning. To elucidate the regulatory mechanisms, we have employed in vitro models composed of purified proteins or cytoplasmic extracts encapsulated in cell-sized water-in-oil droplets. Here we found that the spontaneous rupture of the actin cortex by myosin induced directed motion of droplets. Tug-of-war between actomyosin waves generated from the droplet boundary and stochastically formed actomyosin networks in the bulk space regulates the positioning symmetry of intracellular objects. These findings will help us understand the regulatory mechanisms of various cellular functions orchestrated by the active actin cytoskeleton.

Academic Significance and Societal Importance of the Research Achievements

アクチン細胞骨格は細胞運動や細胞内構造の配置制御など、様々な細胞機能を制御している。アクチン細胞骨格を制御する上流のシグナル系はかなり明らかになりつつあるが、その一方で、最下流のアクチン細胞骨格がどのような物理的機構で細胞機能を制御しているのか、その仕組みはほとんど未解明である。そこで上流のシグナル系を排除するために、精製した細胞骨格タンパク質及び細胞質抽出液を封入した人工細胞を用いて実験を行った。本研究で得られた結果は、アクチン細胞骨格自身が、その力学的相互作用のみで様々な細胞機能を制御する能力を備えていることを示唆している。

Research Products

• [Journal Article] サイズ依存性から見えてきた細胞骨格の自己組織化原理～人工細胞を用いた細胞分裂装置の再構成研究を通して～ (2018)
  • Author(s): 宮﨑 牧人
  • Journal Title: 実験医学 Volume: 36 Pages: 2186-2192
• [Journal Article] Reconstitution of Contractile Actomyosin Rings in Vitro (2016)
  • Author(s): 宮崎牧人、石渡信一
  • Journal Title: Seibutsu Butsuri Volume: 56 Issue: 3 Pages: 174-176
  • DOI: 10.2142/biophys.56.174
  • NAID: 130005153074
  • ISSN: 0582-4052, 1347-4219
  • Peer Reviewed
• [Presentation] Tug-of-war by active gel shapes positioning symmetry in cell-sized compartment (2019)
  • Author(s): Ryota Sakamoto, Yusuke T. Maeda, Tetsuya Hiraiwa, Masatoshi Tanabe, Shin’ichi Ishiwata, Makito Miyazaki
  • Organizer: American Physical Society March Meeting
  • Int'l Joint Research
• [Presentation] Boundary induced actomyosin wave and symmetry breaking of active gels (2018)
  • Author(s): Ryota Sakamoto, Yusuke T. Maeda, Tetsuya Hiraiwa, Masatoshi Tanabe, Shin’ichi Ishiwata, Makito Miyazaki
  • Organizer: Designer Soft Matter (DSM2018)
  • Int'l Joint Research
• [Presentation] Symmetry breaking of actomyosin and actin-waves in confined artificial cells (2018)
  • Author(s): Ryota Sakamoto, Masatoshi Tanabe, Tetsuya Hiraiwa, Shin’ichi Ishiwata, Yusuke T. Maeda, Makito Miyazaki
  • Organizer: 第79回岡崎コンファレンス
• [Presentation] In vitro reconstitution of actin cytoskeleton: Toward a unified understanding of the mechanics of cell motility and division (2018)
  • Author(s): Makito Miyazaki
  • Organizer: 第56回日本生物物理学会年会
  • Invited
• [Presentation] タンパク質から観た細胞の世界～タンパク質分子は如何にして”巨大”な細胞を制御しているのか？～ (2018)
  • Author(s): 宮﨑 牧人
  • Organizer: 第56回日本生物物理学会年会
  • Invited
• [Presentation] Periodic contraction of actomyosin gel and nucleus-like cluster positioning in a confined geometry (2018)
  • Author(s): Ryota Sakamoto, Yusuke T. Maeda, Tetsuya Hiraiwa, Masatoshi Tanabe, Shin’ichi Ishiwata, Makito Miyazaki
  • Organizer: 第56回日本生物物理学会年会
• [Presentation] アクチン系細胞骨格のin vitro再構成：細胞運動と細胞分裂の仕組みの包括的理解を目指して (2018)
  • Author(s): 宮﨑 牧人
  • Organizer: 第91回日本生化学会大会
  • Invited
• [Presentation] Actomyosin waves and percolation control nucleus-like cluster positioning in a cell-sized space (2018)
  • Author(s): Ryota Sakamoto, Yusuke T. Maeda, Tetsuya Hiraiwa, Masatoshi Tanabe, Shin’ichi Ishiwata, Makito Miyazaki
  • Organizer: Advances in Physics of Emergent Orders in Fluctuations (APEF2018)
  • Int'l Joint Research
• [Presentation] アクトミオシンの収縮力によって動く液滴：細胞運動の構成的理解を目指して (2018)
  • Author(s): 宮﨑 牧人
  • Organizer: 第41回日本分子生物学会年会
  • Invited
• [Presentation] 細胞分裂装置のin vitro再構成 (2017)
  • Author(s): 宮崎 牧人
  • Organizer: アクティブマター研究会
  • Place of Presentation: 九州大学，福岡
  • Year and Date: 2017-01-20
  • Invited
• [Presentation] 細胞サイズ閉鎖空間でのアクチン細胞骨格のin vitro再構成 (2017)
  • Author(s): 宮崎 牧人
  • Organizer: 定量生物学の会第８回年会
  • Place of Presentation: 岡崎カンファレンスセンター，愛知
  • Year and Date: 2017-01-08
  • Invited
• [Presentation] In vitro reconstitution of contractile actomyosin rings (2017)
  • Author(s): Makito Miyazaki, Shin’ichi Ishiwata
  • Organizer: The 69th Annual Meeting of the Japan Society for Cell Biology
  • Invited
• [Presentation] 構成的アプローチによる細胞骨格の自己組織化メカニズムの解明 (2017)
  • Author(s): 宮﨑牧人
  • Organizer: 2017年 日本液晶学会討論会・液晶交流会
  • Invited
• [Presentation] Toward a physical understanding of the cell division machinery from the combination of single-molecule and in vitro reconstitution experiments (2017)
  • Author(s): Makito Miyazaki
  • Organizer: The 3rd Africa International Biotechnology and Biomedical Conference (AIBBC2017)
  • Int'l Joint Research / Invited
• [Presentation] 細胞骨格のin vitro再構成：システムサイズ依存性から見えてきた自己組織化機構 (2017)
  • Author(s): 宮﨑牧人
  • Organizer: 2017年度生命科学系学会合同年次大会（ConBio2017: 第40回日本分子生物学会年会＆第90回日本生化学会大会）
  • Invited
• [Presentation] Cell-sized spherical confinement induces the spontaneous formation of contractile actomyosin rings in vitro (2016)
  • Author(s): Makito Miyazaki, Masataka Chiba, Hiroki Eguchi, Takashi Ohki, and Shin’ichi Ishiwata
  • Organizer: IGER International Symposium on “Now in actin study: Motor protein research reaching a new stage”
  • Place of Presentation: Nagoya, Japan
  • Year and Date: 2016-12-12
  • Int'l Joint Research
• [Presentation] In vitro reconstitution of contractile actomyosin cytoskeleton (2016)
  • Author(s): Makito Miyazaki and Shin’ichi Ishiwata
  • Organizer: The 54th Annual Meeting of the Biophysical Society of Japan
  • Place of Presentation: Tsukuba, Japan
  • Year and Date: 2016-11-25
  • Int'l Joint Research / Invited
• [Presentation] Directed motion of cell-sized droplets driven by actomyosin network contraction (2016)
  • Author(s): Yuto Sano, Makito Miyazaki, Kozue Hamao, and Shin’ichi Ishiwata
  • Organizer: The 54th Annual Meeting of the Biophysical Society of Japan
  • Place of Presentation: Tsukuba, Japan
  • Year and Date: 2016-11-25
  • Int'l Joint Research
• [Presentation] 細胞骨格のin vitro再構成：細胞骨格が司る細胞機能発現機構の解明を目指して (2016)
  • Author(s): 宮崎 牧人
  • Organizer: 『細胞を創る』研究会9.0
  • Place of Presentation: 早稲田大学，東京
  • Year and Date: 2016-11-21
  • Invited
• [Presentation] 細胞骨格構造のin vitro再構成 (2016)
  • Author(s): 宮崎 牧人
  • Organizer: 第６回ソフトマター研究会
  • Place of Presentation: 北海道大学，北海道
  • Year and Date: 2016-10-24
  • Invited
• [Presentation] Dynamic properties of bio-motile systems as a liquid-crystalline structure (2016)
  • Author(s): Shin’ichi Ishiwata, Makito Miyazaki, Katsuhiko Sato, Koutaro Nakagome, Kazuya Suzuki, Jun Takagi, Yuta Shimamoto, and Takeshi Itabashi
  • Organizer: 26th International Liquid Crystal Conference (ILCC 2016)
  • Place of Presentation: Kent State University, OH, USA
  • Year and Date: 2016-07-31
  • Int'l Joint Research / Invited
• [Presentation] Self-organization of active cytoskeletal networks in a cell-sized confined space (2016)
  • Author(s): Shin’ichi Ishiwata, Makito Miyazaki, Masataka Chiba, and Kazuya Suzuki
  • Organizer: Biophysical Society 2016 Thematic Meetings “Engineering Approaches to Biomolecular Motors: From in vitro to in vivo”
  • Place of Presentation: Simon Fraser University, Vancouver, Canada
  • Year and Date: 2016-06-14
  • Int'l Joint Research / Invited
• [Presentation] In vitro reconstitution of active cytoskeletal networks in cell-sized droplets (2016)
  • Author(s): Makito Miyazaki, Kazuya Suzuki, and Shin’ichi Ishiwata
  • Organizer: EMN (Energy Materials Nanotechnology) Meeting on Droplets 2016
  • Place of Presentation: San Sebastian, Spain
  • Year and Date: 2016-05-09
  • Int'l Joint Research / Invited