title: How VASP enhances actin-based motility.
abstract: The function of vasodilator-stimulated phosphoprotein (VASP) in motility is analyzed using a biomimetic motility assay in which ActA-coated microspheres propel themselves in a medium containing actin, the Arp2/3 complex, and three regulatory proteins in the absence or presence of VASP. Propulsion is linked to cycles of filament barbed end attachment-branching-detachment-growth in which the ActA-activated Arp2/3 complex incorporates at the junctions of branched filaments. VASP increases the velocity of beads. VASP increases branch spacing of filaments in the actin tail, as it does in lamellipodia in living cells. The effect of VASP on branch spacing of Arp2/3-induced branched actin arrays is opposed to the effect of capping proteins. However, VASP does not compete with capping proteins for binding barbed ends of actin filaments. VASP enhances branched actin polymerization only when ActA is immobilized on beads or on Listeria. VASP increases the rate of dissociation of the branch junction from immobilized ActA, which is the rate-limiting step in the catalytic cycle of site-directed filament branching.
authors.affiliation: Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Samarin
authors.forename: Stephane
authors.initials: S
authors.lastname: Romero
authors.forename: Christine
authors.initials: C
authors.lastname: Kocks
authors.forename: Dominique
authors.initials: D
authors.lastname: Didry
authors.forename: Dominique
authors.initials: D
authors.lastname: Pantaloni
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Carlier
mesh_terms: D051339:Actin Depolymerizing Factors; D000199:Actins / Q000378:metabolism*; D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D051345:Destrin; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism; D008863:Microspheres; D009132:Muscles / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011817:Rabbits; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D015815:Cell Adhesion Molecules; D051345:Destrin; D008840:Microfilament Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein