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Myosin II Activity Softens Cells in Suspension
Chii J Chan1, Andrew E Ekpenyong1, Stefan Golfier2
1Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
Biophysical Journal
|April 23, 2015
Summary
Myosin II inhibition increases the stiffness and solid-like behavior of suspended cells. This contrasts with substrate-adhered cells, highlighting myosin II
Area of Science:
- Cellular mechanics
- Cytoskeletal dynamics
- Biophysics
Background:
- The cellular cytoskeleton, particularly actin, regulates cell mechanics essential for functions like motility and shape change.
- Myosin activity is a key factor in cell mechanics, but its role in suspended cells remains less understood compared to substrate-adhered cells.
Purpose of the Study:
- To investigate the mechanical properties of suspended cells and the role of myosin activity.
- To determine how myosin inhibition affects cell mechanics in suspension across different timescales.
Main Methods:
- Utilized microfluidic optical stretcher, microfluidic microcirculation mimetic, and real-time deformability cytometry.
- Applied pharmacological and genetic perturbations to inhibit myosin activity in various cell types (nonadherent blood cells, mitotic cells, suspended adherent cells).
Main Results:
- Myosin inhibition led to increased stiffness and solid-like behavior in suspended cells across multiple timescales (milliseconds to minutes).
- These findings were consistent across different cell types and myosin-targeting perturbations.
- Observed a distinct functional role for myosin II in suspended cells compared to substrate-adhered cells.
Conclusions:
- Myosin II activity contributes to whole-cell compliance and fluidity in suspended cells.
- This contrasts with substrate-adhered cells, where myosin II generates prestress and increases stiffness.
- Myosin II plays a critical, distinct role in modulating the mechanics of non-adherent cells.
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