Elastic behavior of cross-linked and bundled actin networks

Science. 2004 May 28;304(5675):1301-5. doi: 10.1126/science.1095087.


Networks of cross-linked and bundled actin filaments are ubiquitous in the cellular cytoskeleton, but their elasticity remains poorly understood. We show that these networks exhibit exceptional elastic behavior that reflects the mechanical properties of individual filaments. There are two distinct regimes of elasticity, one reflecting bending of single filaments and a second reflecting stretching of entropic fluctuations of filament length. The mechanical stiffness can vary by several decades with small changes in cross-link concentration, and can increase markedly upon application of external stress. We parameterize the full range of behavior in a state diagram and elucidate its origin with a robust model.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actin Cytoskeleton / chemistry*
  • Actin Cytoskeleton / metabolism
  • Actins / chemistry*
  • Actins / metabolism
  • Biopolymers / chemistry
  • Biopolymers / metabolism
  • Elasticity
  • Entropy
  • Mathematics
  • Microfilament Proteins / chemistry
  • Microfilament Proteins / metabolism
  • Models, Biological
  • Stress, Mechanical


  • Actins
  • Biopolymers
  • Microfilament Proteins
  • scruin protein, Horseshoe Crab