title: VASP governs actin dynamics by modulating filament anchoring.
abstract: Actin filament dynamics at the cell membrane are important for cell-matrix and cell-cell adhesions and the protrusion of the leading edge. Since actin filaments must be connected to the cell membrane to exert forces but must also detach from the membrane to allow it to move and evolve, the balance between actin filament tethering and detachment at adhesion sites and the leading edge is key for cell shape changes and motility. How this fine tuning is performed in cells remains an open question, but possible candidates are the Drosophila enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) family of proteins, which localize to dynamic actin structures in the cell. Here we study VASP-mediated actin-related proteins 2/3 (Arp2/3) complex-dependent actin dynamics using a substrate that mimics the fluid properties of the cell membrane: an oil-water interface. We show evidence that polymerization activators undergo diffusion and convection on the fluid surface, due to continual attachment and detachment to the actin network. These dynamics are enhanced in the presence of VASP, and we observe cycles of catastrophic detachment of the actin network from the surface, resulting in stop-and-go motion. These results point to a role for VASP in the modulation of filament anchoring, with implications for actin dynamics at cell adhesions and at the leading edge of the cell.
authors.affiliation: Laboratoire Physicochimie Curie UMR 168 CNRS, Institut Curie-Section de Recherche, 11 rue Pierre et Marie Curie, 75231 Paris, cedex 05, France.
authors.forename: Léa
authors.initials: L
authors.lastname: Trichet
authors.forename: Otger
authors.initials: O
authors.lastname: Campàs
authors.forename: Cécile
authors.initials: C
authors.lastname: Sykes
authors.forename: Julie
authors.initials: J
authors.lastname: Plastino
mesh_terms: D008841:Actin Cytoskeleton / Q000737:chemistry* / Q000648:ultrastructure; D000199:Actins / Q000737:chemistry* / Q000648:ultrastructure; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000648:ultrastructure; D007700:Kinetics; D008840:Microfilament Proteins / Q000737:chemistry* / Q000648:ultrastructure; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000648:ultrastructure; D009038:Motion; D010750:Phosphoproteins / Q000737:chemistry* / Q000648:ultrastructure; D011485:Protein Binding; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D000199:Actins; D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; D020409:Molecular Motor Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein