Biophysics of actin filament severing by cofilin

FEBS Lett. 2013 Apr 17;587(8):1215-9. doi: 10.1016/j.febslet.2013.01.062. Epub 2013 Feb 5.


The continuous assembly and disassembly of actin filament networks is vital for cellular processes including division, growth, and motility. Network remodeling is facilitated by cofilins, a family of essential regulatory proteins that fragment actin filaments. Cofilin induces net structural changes in filaments that render them more compliant in bending and twisting. A model in which local stress accumulation at mechanical discontinuities, such as boundaries of bare and cofilin-decorated filament segments, accounts for the cofilin concentration dependence of severing, including maximal activity at sub-stoichiometric binding densities. Real-time imaging of cofilin-mediated filament severing supports the boundary-fracture model. The severing model predicts that fragmentation is promoted by factors modulating filament mechanics (e.g. tethering, cross-linking, or deformation), possibly explaining enhanced in vivo severing activities.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Actin Cytoskeleton / chemistry*
  • Actin Cytoskeleton / metabolism
  • Actin Depolymerizing Factors / chemistry*
  • Actin Depolymerizing Factors / metabolism
  • Actins / chemistry*
  • Actins / metabolism
  • Animals
  • Biophysical Phenomena
  • Humans
  • Kinetics
  • Models, Molecular*
  • Protein Binding
  • Thermodynamics


  • Actin Depolymerizing Factors
  • Actins