title: An active biopolymer network controlled by molecular motors.
abstract: We describe an active polymer network in which processive molecular motors control network elasticity. This system consists of actin filaments cross-linked by filamin A (FLNa) and contracted by bipolar filaments of muscle myosin II. The myosin motors stiffen the network by more than two orders of magnitude by pulling on actin filaments anchored in the network by FLNa cross-links, thereby generating internal stress. The stiffening response closely mimics the effects of external stress applied by mechanical shear. Both internal and external stresses can drive the network into a highly nonlinear, stiffened regime. The active stress reaches values that are equivalent to an external stress of 14 Pa, consistent with a 1-pN force per myosin head. This active network mimics many mechanical properties of cells and suggests that adherent cells exert mechanical control by operating in a nonlinear regime where cell stiffness is sensitive to changes in motor activity. This design principle may be applicable to engineering novel biologically inspired, active materials that adjust their own stiffness by internal catalytic control.
authors: Department of Physics and Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138.
authors: Gijsje H
authors: GH
authors: Koenderink
authors: Zvonimir
authors: Z
authors: Dogic
authors: Fumihiko
authors: F
authors: Nakamura
authors: Poul M
authors: PM
authors: Bendix
authors: Frederick C
authors: FC
authors: MacKintosh
authors: John H
authors: JH
authors: Hartwig
authors: Thomas P
authors: TP
authors: Stossel
authors: David A
authors: DA
authors: Weitz
mesh_terms: D000199:Actins / Q000378:metabolism*; D001696:Biomechanical Phenomena; D001698:Biomedical Engineering / Q000379:methods*; D003285:Contractile Proteins / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D004548:Elasticity; D064448:Filamins; D008840:Microfilament Proteins / Q000378:metabolism*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism*; D012212:Rheology
chemical_list: D000199:Actins; D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D020409:Molecular Motor Proteins; D011108:Polymers