A single charge in the actin binding domain of fascin can independently tune the linear and non-linear response of an actin bundle network

  • M. Maier
  • K. W. Müller
  • C. Heussinger
  • S. Köhler
  • W. A. Wall
  • A. R. Bausch
  • O. Lieleg
Open AccessRegular Article

DOI: 10.1140/epje/i2015-15050-3

Cite this article as:
Maier, M., Müller, K.W., Heussinger, C. et al. Eur. Phys. J. E (2015) 38: 50. doi:10.1140/epje/i2015-15050-3

Abstract

Actin binding proteins (ABPs) not only set the structure of actin filament assemblies but also mediate the frequency-dependent viscoelastic moduli of cross-linked and bundled actin networks. Point mutations in the actin binding domain of those ABPs can tune the association and dissociation dynamics of the actin/ABP bond and thus modulate the network mechanics both in the linear and non-linear response regime. We here demonstrate how the exchange of a single charged amino acid in the actin binding domain of the ABP fascin triggers such a modulation of the network rheology. Whereas the overall structure of the bundle networks is conserved, the transition point from strain-hardening to strain-weakening sensitively depends on the cross-linker off-rate and the applied shear rate. Our experimental results are consistent both with numerical simulations of a cross-linked bundle network and a theoretical description of the bundle network mechanics which is based on non-affine bending deformations and force-dependent cross-link dynamics.

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Keywords

Soft Matter: Polymers and Polyelectrolytes 
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© The Author(s) 2015

Authors and Affiliations

  • M. Maier
    • 1
  • K. W. Müller
    • 2
  • C. Heussinger
    • 3
  • S. Köhler
    • 4
  • W. A. Wall
    • 2
  • A. R. Bausch
    • 1
  • O. Lieleg
    • 5
  1. 1.Lehrstuhl für Zellbiophysik E27, Physik-DepartmentTechnische Universität MünchenGarchingGermany
  2. 2.Institute for Computational Mechanics, Department of Mechanical EngineeringTechnische Universität MünchenGarchingGermany
  3. 3.Institute for Theoretical PhysicsUniversität GöttingenGöttingenGermany
  4. 4.Department of Molecular and Cell BiologyUniversity of CaliforniaBerkeleyUSA
  5. 5.Institute of Medical Engineering IMETUM and Department of Mechanical EngineeringTechnische Universität MünchenGarchingGermany