title: Internal motility in stiffening actin-myosin networks.
abstract: We present a study on filamentous actin solutions containing heavy meromyosin subfragments of myosin II motor molecules. We focus on the viscoelastic phase behavior and internal dynamics of such networks during adenosine-triphosphate depletion. By combining microrheology and fluorescence microscopy, we observed a sol-gel transition accompanied by a sudden onset of directed filament motion. We interpret the sol-gel transition in terms of myosin II enzymology, and suggest a "zipping" mechanism to explain the filament motion in the vicinity of the sol-gel transition.
authors.affiliation: Physik Department, Technische Universität München, D-85747 Garching, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Uhde
authors.forename: Manfred
authors.initials: M
authors.lastname: Keller
authors.forename: Erich
authors.initials: E
authors.lastname: Sackmann
authors.forename: Andrea
authors.initials: A
authors.lastname: Parmeggiani
authors.forename: Erwin
authors.initials: E
authors.lastname: Frey
mesh_terms: D000199:Actins / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D000255:Adenosine Triphosphate / Q000737:chemistry*; D004548:Elasticity; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000648:ultrastructure; D009038:Motion; D046912:Multiprotein Complexes / Q000032:analysis / Q000737:chemistry / Q000648:ultrastructure; D015879:Myosin Subfragments / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D024462:Myosin Type II / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D044367:Phase Transition; D011487:Protein Conformation; D012996:Solutions; D014783:Viscosity
chemical_list: D000199:Actins; D020409:Molecular Motor Proteins; D046912:Multiprotein Complexes; D015879:Myosin Subfragments; D012996:Solutions; D000255:Adenosine Triphosphate; D024462:Myosin Type II