title: Nonequilibrium fluctuations of a remodeling in vitro cytoskeleton.
abstract: Motor proteins actively contract the actin cytoskeleton of cells and thereby give rise to nonequilibrium fluctuations as well as changes in the architecture of the cytoskeleton. Here, we show, by video microrheology of a reconstituted cytoskeleton, that motors generate time-dependent nonequilibrium fluctuations, which evolve as the network is remodeled. At earlier times, the fluctuation spectrum is dominated by strong non-Gaussian fluctuations, which arise from large displacements. At later times, directed displacements are infrequent and finally disappear. We show that these effects are due to contractile coarsening of the network into large actin-myosin foci.
authors.affiliation: Biological Soft Matter Group, FOM Institute for Atomic and Molecular Physics, AMOLF, Science Park 104, Amsterdam 1098 XG, The Netherlands.
authors.forename: Björn
authors.initials: B
authors.lastname: Stuhrmann
authors.forename: Marina
authors.initials: M
authors.lastname: Soares E Silva
authors.forename: Martin
authors.initials: M
authors.lastname: Depken
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Mackintosh
authors.forename: Gijsje H
authors.initials: GH
authors.lastname: Koenderink
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002470:Cell Survival; D003599:Cytoskeleton / Q000378:metabolism*; D055616:Microtechnology; D009218:Myosins / Q000378:metabolism; D011817:Rabbits; D012212:Rheology; D013997:Time Factors
chemical_list: D000199:Actins; D009218:Myosins