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Updated: Feb 6, 2026

Quantification of Filamentous Actin F-actin Puncta in Rat Cortical Neurons
Published on: February 10, 2016
My various thoughts on actin
Fumio Oosawa1,2,3
1Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan.
Abstract:
An enormous amount of research has been performed to characterize actin dynamics. Structural biology investigations have determined the localization of main chains and their changes coupled with G (Globular)-F (Filamentous) transformation of actin, whereas local thermal fluctuations that may be caused by free rotations of the tips of side chains are not yet fully investigated. This paper argues if the entropy change of actin accompanied by the G-F transformation is simply attributable to the changes in hydration. It took almost 10 years to understand that the actin filament is semi-flexible. This flexibility was visually confirmed as the development of optical microscope techniques, and the direct observation of actin severing events in the presence of actin binding proteins became possible. Finally, I expect the deep understanding of actin dynamics will lead to the elucidation of self-assembly mechanisms of the living creature.
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