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Updated: Jul 20, 2026

Probing Myosin Ensemble Mechanics in Actin Filament Bundles Using Optical Tweezers
Published on: May 4, 2022
Chara myosin and the energy of cytoplasmic streaming
Keiichi Yamamoto1, Kiyo Shimada, Khoji Ito
1Department of Biology, Chiba University, Inage-ku, Chiba, 263-8522 Japan. yamamoto@bio.s.chiba-u.ac.jp
Abstract:
Recently, it was found that myosin generating very fast cytoplasmic streaming in Chara corallina has very high ATPase activity. To estimate the energy consumed by this myosin, its concentration in the internodal cells of C. corallina was determined by quantitative immunoblot. It was found that the concentration of Chara myosin was considerably high (200 nM) and the amount of ATP consumed by this myosin would exceed that supplied by dark respiration if all myosin molecules were fully activated by the interaction with actin. These results and model calculations suggested that the energy required to generate cytoplasmic streaming is very small and only one-hundredth of the existing myosin is enough to maintain the force for the streaming in the Chara cell.
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