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Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy
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Deciphering Mechanochemical Influences of Emergent Actomyosin Crosstalk Using QCM-D
Emily M Kerivan1, Victoria N Amari1, William B Weeks1
1Department of Biomedical Engineering, University of Mississippi, University, MS 38677 USA.
Cellular and Molecular Bioengineering
|February 14, 2025
Summary
This study used QCM-D to measure how actomyosin bundles change mechanics with myosin II concentration and nucleotide state. Findings reveal how cytoskeletal protein ensembles exhibit emergent mechanics and force sensing.
Area of Science:
- Biophysics
- Cellular Mechanics
- Biomaterials Science
Background:
- Cytoskeletal protein ensembles display emergent mechanics, where their collective behavior differs from individual component properties.
- Filaments can function as force sensors, modulating motor protein activity through feedback mechanisms.
Purpose of the Study:
- To investigate the design principles of emergent mechanics in actomyosin bundles.
- To utilize Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) to measure mechanical responses to environmental changes affecting myosin II motor behavior.
Main Methods:
- Employed QCM-D to analyze actin-myosin bundle viscoelasticity.
- Constructed actomyosin bundles on a QCM-D sensor using microfluidics.
- Measured frequency and dissipation changes upon addition of components and nucleotide variations (ATP vs. ADP).
Main Results:
- Decreased myosin II concentration led to reduced frequency and dissipation shifts.
- Different nucleotide conditions (ATP vs. ADP) produced distinct viscoelastic signatures.
- Myosin II in an ADP-bound state increased bundle rigidity by tightly binding actin, acting as a static crosslinker and recruiting more actin.
Conclusions:
- QCM-D effectively detects molecular-level changes in actomyosin viscoelasticity.
- Results support actin's role in mechanical force sensing and provide insights into cytoskeletal ensemble crosstalk.
- This method can be adapted to study complex cytoskeletal systems and intracellular mechanosensing.
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