Theory 34/Cytoskeletal Mechanics
Contractility Is a Duty Ratio
The claim
Cell contractility is set by the ratio of myosin activity to crosslinker unbinding rate rather than by myosin activity alone, so a network that remodels quickly cannot sustain force.
01The mechanism
Force must be transmitted through connections that persist; if crosslinkers unbind faster than myosin generates force, the network slips.
02Predictions
- P1Contractility should track the duty ratio.
- P2Myosin activity alone should mispredict.
03Refutation
Contractility tracking myosin activity would remove the unbinding term.