The small heat shock protein Hsp27 affects assembly dynamics and structure of keratin intermediate filament networks

Biophys J. 2013 Oct 15;105(8):1778-85. doi: 10.1016/j.bpj.2013.09.007.


The mechanical properties of living cells are essential for many processes. They are defined by the cytoskeleton, a composite network of protein fibers. Thus, the precise control of its architecture is of paramount importance. Our knowledge about the molecular and physical mechanisms defining the network structure remains scarce, especially for the intermediate filament cytoskeleton. Here, we investigate the effect of small heat shock proteins on the keratin 8/18 intermediate filament cytoskeleton using a well-controlled model system of reconstituted keratin networks. We demonstrate that Hsp27 severely alters the structure of such networks by changing their assembly dynamics. Furthermore, the C-terminal tail domain of keratin 8 is shown to be essential for this effect. Combining results from fluorescence and electron microscopy with data from analytical ultracentrifugation reveals the crucial role of kinetic trapping in keratin network formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cluster Analysis
  • HSP27 Heat-Shock Proteins / metabolism*
  • HSP27 Heat-Shock Proteins / ultrastructure
  • Intermediate Filaments / chemistry
  • Intermediate Filaments / metabolism*
  • Intermediate Filaments / ultrastructure
  • Keratins / chemistry*
  • Keratins / metabolism*
  • Keratins / ultrastructure
  • Kinetics
  • Mutant Proteins / chemistry
  • Mutant Proteins / metabolism
  • Protein Binding
  • Protein Multimerization
  • Solubility
  • Structure-Activity Relationship


  • HSP27 Heat-Shock Proteins
  • Mutant Proteins
  • Keratins