title: The dynamics of actin-based motility depend on surface parameters.
abstract: In cells, actin polymerization at the plasma membrane is induced by the recruitment of proteins such as the Arp2/3 complex, and the zyxin/VASP complex. The physical mechanism of force generation by actin polymerization has been described theoretically using various approaches, but lacks support from experimental data. By the use of reconstituted motility medium, we find that the Wiskott Aldrich syndrome protein (WASP) subdomain, known as VCA, is sufficient to induce actin polymerization and movement when grafted on microspheres. Changes in the surface density of VCA protein or in the microsphere diameter markedly affect the velocity regime, shifting from a continuous to a jerky movement resembling that of the mutated 'hopping' Listeria. These results highlight how simple physical parameters such as surface geometry and protein density directly affect spatially controlled actin polymerization, and play a fundamental role in actin-dependent movement.
authors.affiliation: Laboratoire Physico-chimie 'Curie', UMR 168 CNRS/Institut Curie, 11, rue Pierre et Marie Curie, 75231 Paris cedex 05, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Bernheim-Groswasser
authors.forename: Sebastian
authors.initials: S
authors.lastname: Wiesner
authors.forename: Roy M
authors.initials: RM
authors.lastname: Golsteyn
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Carlier
authors.forename: Cécile
authors.initials: C
authors.lastname: Sykes
mesh_terms: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism; D003598:Cytoskeletal Proteins; D008089:Listeria monocytogenes / Q000502:physiology*; D008863:Microspheres; D009068:Movement; D011137:Polystyrenes; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D012763:Shigella flexneri / Q000502:physiology*; D051316:Wiskott-Aldrich Syndrome Protein
chemical_list: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D001704:Biopolymers; D003598:Cytoskeletal Proteins; D011137:Polystyrenes; D011506:Proteins; D051316:Wiskott-Aldrich Syndrome Protein