title: Wrinkling of a spherical lipid interface induced by actomyosin cortex.
abstract: Actomyosin actively generates contractile forces that provide the plasma membrane with the deformation stresses essential to carry out biological processes. Although the contractile property of purified actomyosin has been extensively studied, to understand the physical contribution of the actomyosin contractile force on a deformable membrane is still a challenging problem and of great interest in the field of biophysics. Here, we reconstitute a model system with a cell-sized deformable interface that exhibits anomalous curvature-dependent wrinkling caused by the actomyosin cortex underneath the spherical closed interface. Through a shape analysis of the wrinkling deformation, we find that the dominant contributor to the wrinkled shape changes from bending elasticity to stretching elasticity of the reconstituted cortex upon increasing the droplet curvature radius of the order of the cell size, i.e., tens of micrometers. The observed curvature dependence is explained by the theoretical description of the cortex elasticity and contractility. Our present results provide a fundamental insight into the deformation of a curved membrane induced by the actomyosin cortex.
authors.affiliation: Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ito
authors.affiliation: Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Nishigami
authors.affiliation: Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo 678-1297, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Sonobe
authors.affiliation: Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Ichikawa
mesh_terms: D000205:Actomyosin / Q000378:metabolism*; D000656:Amoeba / Q000166:cytology; D001696:Biomechanical Phenomena; D002462:Cell Membrane / Q000378:metabolism; D004548:Elasticity; D055595:Mechanical Phenomena; D008954:Models, Biological
chemical_list: D000205:Actomyosin