Factors influencing the determination of cell traction forces

We are using video-enhanced light microscopy to investigate the pattern and magnitude of forces that fish keratocytes exert on flexible silicone rubber substrata. Our goal is a clearer understanding of the way molecular motors acting through the cytoskeleton co-ordinate their efforts into locomotion at cell velocities up to 1 μm/sec. Cell traction forces were previously observed as wrinkles(Fig.l) in strong silicone rubber films by Harris.(l) These forces are now measureable by two independant means.In the first of these assays, weakly crosslinked films are made, into which latex beads have been embedded.(Fig.2) These films report local cell-mediated traction forces as bead displacements in the plane of the film(Fig.3), which recover when the applied force is released. Calibrated flexible glass microneedles are then used to reproduce the translation of individual beads. We estimate the force required to distort these films to be 0.5 mdyne/μm of bead movement. Video-frame analysis of bead trajectories is providing data on the relative localisation, dissipation and kinetics of traction forces.

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Cell Traction Forces Direct Fibronectin Matrix Assembly

Biophysical Journal ◽

10.1016/j.bpj.2008.10.009 ◽

2009 ◽

Vol 96 (2) ◽

pp. 729-738 ◽

Cited By ~ 99

Author(s):

Christopher A. Lemmon ◽

Christopher S. Chen ◽

Lewis H. Romer

Keyword(s):

Matrix Assembly ◽

Traction Forces ◽

Cell Traction Forces ◽

Fibronectin Matrix ◽

Cell Traction

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Dissipation of contractile forces: the missing piece in cell mechanics

Molecular Biology of the Cell ◽

10.1091/mbc.e16-09-0672 ◽

2017 ◽

Vol 28 (14) ◽

pp. 1825-1832 ◽

Cited By ~ 12

Author(s):

Laetitia Kurzawa ◽

Benoit Vianay ◽

Fabrice Senger ◽

Timothée Vignaud ◽

Laurent Blanchoin ◽

...

Keyword(s):

Cell Mechanics ◽

Force Production ◽

Traction Force ◽

Structural Rearrangements ◽

Force Transmission ◽

Traction Forces ◽

Cell Traction Forces ◽

Cell Traction ◽

Contractile Forces ◽

Fiber Contraction

Mechanical forces are key regulators of cell and tissue physiology. The basic molecular mechanism of fiber contraction by the sliding of actin filament upon myosin leading to conformational change has been known for decades. The regulation of force generation at the level of the cell, however, is still far from elucidated. Indeed, the magnitude of cell traction forces on the underlying extracellular matrix in culture is almost impossible to predict or experimentally control. The considerable variability in measurements of cell-traction forces indicates that they may not be the optimal readout to properly characterize cell contractile state and that a significant part of the contractile energy is not transferred to cell anchorage but instead is involved in actin network dynamics. Here we discuss the experimental, numerical, and biological parameters that may be responsible for the variability in traction force production. We argue that limiting these sources of variability and investigating the dissipation of mechanical work that occurs with structural rearrangements and the disengagement of force transmission is key for further understanding of cell mechanics.

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