Myosin dynamics in cultured skeletal muscle cells and isolated fibers

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K08079
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Integrative animal science
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: OJIMA Koichi 国立研究開発法人農業・食品産業技術総合研究機構, 畜産研究部門, 上級研究員 (60415544)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: ミオシン / 骨格筋

Outline of Final Research Achievements

In skeletal muscles, myosin is a major component of myofibrillar proteins. In myofibrils, approximately 300 myosin molecules form a single thick filament where continuous turnover of myosin is observed. However, we have not fully understood the mechanism by which myosin replacement is regulated in skeletal muscle cells. Here, we showed that one of the sources for myosin substitution in myofibrils was stored myosin in the cytoplasm of myotubes. Next, we searched for factors to affect myosin replacement rate in myofibrils. Our results demonstrated that chaperone activity of Hsp90 increased myosin replacement rate through upregulation of myosin amount in cultured myotubes. Finally, we generated genetically modified mouse in which red fluorescence protein fused myosin heavy chain was expressed in skeletal muscle cells to monitor the dynamics of endogenous myosin.

Free Research Field

骨格筋細胞生物学

Academic Significance and Societal Importance of the Research Achievements

従来までは骨格筋型を判定するためには、生体から骨格筋組織を採取し、特異的抗体を用いて抗体染色を行うなど煩雑な作業が必要であった。本研究において作出した蛍光タンパク質を融合したミオシンを発現するマウスを用いることで、蛍光波長により筋型を視覚的に簡便に区別することが可能となった。さらに、内因性のミオシンの動態を顕微鏡下で追跡できることから、ミオシンを研究する上で非常にパワフルなツールになる。