Twist response of actin filaments
Abstract
Actin cytoskeleton force generation, sensing, and adaptation are dictated by the bending and twisting mechanics of filaments. Here, we use magnetic tweezers and microfluidics to twist and pull individual actin filaments and evaluate their response to applied loads. Twisted filaments bend and dissipate torsional strain by adopting a supercoiled plectoneme. Pulling prevents plectoneme formation, which causes twisted filaments to sever. Analysis over a range of twisting and pulling forces and direct visualization of filament and single subunit twisting fluctuations yield an actin filament torsional persistence length of ~10 µm, similar to the bending persistence length. Filament severing by cofilin is driven by local twist strain at boundaries between bare and decorated segments and is accelerated by low pN pulling forces. This work explains how contractile forces generated by myosin motors accelerate filament severing by cofilin and establishes a role for filament twisting in the regulation of actin filament stability and assembly dynamics.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 19, 2023
- Source ID
- 10.1073/pnas.2208536120
Entities
People
- Charles V Sindelar
- Enrique M. De La Cruz
- Jeffrey P. Bibeau
- Nandan G. Pandit
- Nooshin Shatery Nejad
- Shawn Gray
- Wenxiang Cao
Organizations
- National Institute of General Medical Sciences
- Yale University