My various thoughts on actin

• Published in: Biophysics and Physicobiology Vol. 15; pp. 151 - 158
• Main Author: Oosawa, Fumio
• Format: Journal Article
• Language: English
• Published: Japan The Biophysical Society of Japan 01.01.2018; The Biophysical Society of Japan (BSJ)
• Subjects: actin binding proteins; actin thermodynamics; entropy changes in G-F transformation; flexibility of actin filament; hydration of actin; Review; actin binding proteins; flexibility of actin filament; actin thermodynamics; entropy changes in G-F transformation; hydration of actin
• ISSN: 2189-4779; 2189-4779
• DOI: 10.2142/biophysico.15.0_151

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.