title: Comparative maps of motion and assembly of filamentous actin and myosin II in migrating cells.
abstract: To understand the mechanism of cell migration, one needs to know how the parts of the motile machinery of the cell are assembled and how they move with respect to each other. Actin and myosin II are thought to be the major structural and force-generating components of this machinery (Mitchison and Cramer, 1996; Parent, 2004). The movement of myosin II along actin filaments is thought to generate contractile force contributing to cell translocation, but the relative motion of the two proteins has not been investigated. We use fluorescence speckle and conventional fluorescence microscopy, image analysis, and computer tracking techniques to generate comparative velocity and assembly maps of actin and myosin II over the entire cell in a simple model system of persistently migrating fish epidermal keratocytes. The results demonstrate contrasting polarized assembly patterns of the two components, indicate force generation at the lamellipodium-cell body transition zone, and suggest a mechanism of anisotropic network contraction via sliding of myosin II assemblies along divergent actin filaments.
authors.affiliation: Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Schaub
authors.forename: Sophie
authors.initials: S
authors.lastname: Bohnet
authors.forename: Valérie M
authors.initials: VM
authors.lastname: Laurent
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Meister
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Verkhovsky
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000818:Animals; D001696:Biomechanical Phenomena; D002465:Cell Movement / Q000187:drug effects; D016764:Cell Polarity / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D005399:Fishes; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D015603:Keratinocytes / Q000166:cytology* / Q000187:drug effects; D008954:Models, Biological; D009038:Motion; D024462:Myosin Type II / Q000378:metabolism*; D011554:Pseudopodia / Q000187:drug effects
chemical_list: D006576:Heterocyclic Compounds, 4 or More Rings; C472645:blebbistatin; D024462:Myosin Type II