title: Molecular origin of strain softening in cross-linked F-actin networks.
abstract: Two types of measurement are presented that relate molecular events to macroscopic behavior of F-actin networks. First, shear modulus is measured by oscillating an embedded microbead. Second, a microbead is translated at constant rate and transitions in the resisting force are observed. The loading rate dependence of the force at the transitions is similar to that of the molecular unbinding force, suggesting that they share a common origin. Reversibility tests of shear modulus provide further evidence that strain softening of F-actin networks is caused by force-induced rupture of cross-links.
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Hyungsuk
authors.initials: H
authors.lastname: Lee
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Ferrer
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Lang
authors.forename: Roger D
authors.initials: RD
authors.lastname: Kamm
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000648:ultrastructure*; D003198:Computer Simulation; D003432:Cross-Linking Reagents / Q000737:chemistry; D055119:Elastic Modulus; D006244:Hardness; D008956:Models, Chemical; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000648:ultrastructure; D011487:Protein Conformation; D013314:Stress, Mechanical
chemical_list: D000199:Actins; D003432:Cross-Linking Reagents; D046912:Multiprotein Complexes