Biophysical characterization of cofilin-induced extension-torsion coupling in actin filaments

Jae In Kim; Junpyo Kwon; Inchul Baek; Sungsoo Na

doi:10.1016/j.jbiomech.2016.04.015

Biophysical characterization of cofilin-induced extension-torsion coupling in actin filaments

J Biomech. 2016 Jun 14;49(9):1831-1835. doi: 10.1016/j.jbiomech.2016.04.015. Epub 2016 Apr 26.

Authors

Jae In Kim¹, Junpyo Kwon¹, Inchul Baek¹, Sungsoo Na²

Affiliations

¹ Department of Mechanical Engineering, Korea University, Anam-dong 5-ga, Sungbuk-gu, Seoul 136-701, Republic of Korea.
² Department of Mechanical Engineering, Korea University, Anam-dong 5-ga, Sungbuk-gu, Seoul 136-701, Republic of Korea. Electronic address: nass@korea.ac.kr.

PMID: 27143106
DOI: 10.1016/j.jbiomech.2016.04.015

Abstract

Cofilin makes the actin filament flexible and thermally unstable by disassembling the filament and inducing bending and torsional compliance. Actin monomers bound to cofilin are able to chemically and mechanically interact in response to external forces. In this study, we performed two molecular dynamics tensile tests for actin and cofilactin filaments under identical conditions. Surprisingly, cofilactin filaments were found to be twisted, generating shear stress caused by torsion. Additionally, analysis by plane stress assumption indicated that the extension-torsion coupling effect increases the amount of principal stress by 10%. Using elasticity and solid mechanics theories, our study elucidates the role of cofilin in the disassembly of actin filaments under tensile forces.

Keywords: Actin; Cofilin; Coupling effect; Extension; SMD; Torsion.

MeSH terms

Actin Cytoskeleton / physiology*
Actin Depolymerizing Factors / physiology*
Biophysical Phenomena
Elasticity
Molecular Dynamics Simulation
Stress, Mechanical

Substances

Actin Depolymerizing Factors