title: Dynamical organization of the cytoskeletal cortex probed by micropipette aspiration.
abstract: Bleb-based cell motility proceeds by the successive inflation and retraction of large spherical membrane protrusions ("blebs") coupled with substrate adhesion. In addition to their role in motility, cellular blebs constitute a remarkable illustration of the dynamical interactions between the cytoskeletal cortex and the plasma membrane. Here we study the bleb-based motions of Entamoeba histolytica in the constrained geometry of a micropipette. We construct a generic theoretical model that combines the polymerization of an actin cortex underneath the plasma membrane with the myosin-generated contractile stress in the cortex and the stress-induced failure of membrane-cortex adhesion. One major parameter dictating the cell response to micropipette suction is the stationary cortex thickness, controlled by actin polymerization and depolymerization. The other relevant physical parameters can be combined into two characteristic cortex thicknesses for which the myosin stress (i) balances the suction pressure and (ii) provokes membrane-cortex unbinding. We propose a general phase diagram for cell motions inside a micropipette by comparing these three thicknesses. In particular, we theoretically predict and experimentally verify the existence of saltatory and oscillatory motions for a well-defined range of micropipette suction pressures.
authors: Laboratoire Gulliver, Centre National de la Recherche Scientifique-Ecole Superieure de Physique et Chimie Industrielles, Unité Mixte de Recherche 7083, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors: Jan
authors: J
authors: Brugués
authors: Benoit
authors: B
authors: Maugis
authors: Jaume
authors: J
authors: Casademunt
authors: Pierre
authors: P
authors: Nassoy
authors: François
authors: F
authors: Amblard
authors: Pierre
authors: P
authors: Sens
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism*; D000465:Algorithms; D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism*; D004748:Entamoeba histolytica / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D008954:Models, Biological; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D009218:Myosins / Q000378:metabolism; D010274:Parasitology / Q000295:instrumentation / Q000379:methods; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D009218:Myosins