Stochastic force generation by small ensembles of myosin II motors
Abstract
Forces in the actin cytoskeleton are generated by small groups of non-processive myosin II motors for which stochastic effects are highly relevant. Using a crossbridge model with the assumptions of fast powerstroke kinetics and equal load sharing between equivalent states, we derive a one-step master equation for the activity of a finite-sized ensemble of mechanically coupled myosin II motors. For constant external load, this approach yields analytical results for duty ratio and force-velocity relation as a function of ensemble size. We find that stochastic effects cannot be neglected for ensemble sizes below 15. The one-step master equation can be used also for efficient computer simulations with linear elastic external load and reveals the sequence of build-up of force and ensemble rupture that is characteristic for reconstituted actomyosin contractility.
Keywords
Cite
@article{arxiv.1202.3038,
title = {Stochastic force generation by small ensembles of myosin II motors},
author = {Thorsten Erdmann and Ulrich S. Schwarz},
journal= {arXiv preprint arXiv:1202.3038},
year = {2015}
}
Comments
revtex, 5 pages, 4 figures