Emergent properties of composite semiflexible biopolymer networks

Mikkel H. Jensen, Eliza J. Morris, Robert D. Goldman, David A. Weitz

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


The semiflexible polymers filamentous actin (F-actin) and intermediate filaments (IF) both form complex networks within the cell, and together are key determinants of cellular stiffness. While the mechanics of F-actin networks together with stiff microtubules have been characterized, the interplay between F-actin and IF networks is largely unknown, necessitating the study of composite networks using mixtures of semiflexible biopolymers. We employ bulk rheology in a simplified in vitro system to uncover the fundamental mechanical interactions between networks of the 2 semiflexible polymers, F-actin and vimentin IF. Surprisingly, co-polymerization of actin and vimentin can produce composite networks either stronger or weaker than pure F-actin networks. We show that this effect occurs through steric constraints imposed by IF on F-actin during network formation and filament crosslinking, highlighting novel emergent behavior in composite semiflexible networks.

Original languageEnglish (US)
Pages (from-to)138-143
Number of pages6
Issue number4-5
StatePublished - 2014


  • F-actin, filamentous actin
  • G-actin, globular (monomeric) actin
  • IF, intermediate filament
  • actin
  • composite
  • intermediate filaments
  • model systems; networks
  • rheology
  • semiflexible polymers
  • vimentin

ASJC Scopus subject areas

  • Structural Biology
  • Cell Biology


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