title: Formation and maintenance of tubular membrane projections: experiments and numerical calculations.
abstract: To study the mechanical properties of lipid membranes, we manipulated liposomes by using a system comprising polystyrene beads and laser tweezers, and measured the force required to transform their shapes. When two beads pushed the membrane from inside, spherical liposomes transformed into a lemon-shape. Then a discontinuous shape transformation occurred to form a membrane tube from either end of the liposomes, and the force dropped drastically. We analyzed these processes using a mathematical model based on the bending elasticity of the membranes. Numerical calculations showed that when the bead size was taken into account, the model reproduced both the liposomal shape transformation and the force-extension relation. This result suggests that the size of the beads is responsible for the existence of a force barrier for the tube formation.
authors.affiliation: GraduateSchool of Maritime Sciences, Kobe University, 5-1-1, Fukae-minami-machi, Higashinada-ku, Kobe 658-0022, Japan. umeda@maritime.kobe-u.a.jp
authors.forename: Tamiki
authors.initials: T
authors.lastname: Umeda
authors.forename: Takehiko
authors.initials: T
authors.lastname: Inaba
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ishijima
authors.forename: Kingo
authors.initials: K
authors.lastname: Takiguchi
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Hotani
mesh_terms: D008081:Liposomes / Q000737:chemistry*; D008560:Membrane Fluidity; D008954:Models, Biological
chemical_list: D008081:Liposomes