title: Cell-sized asymmetric lipid vesicles facilitate the investigation of asymmetric membranes.
abstract: Asymmetric lipid giant vesicles have been used to model the biochemical reactions in cell membranes. However, methods for producing asymmetric giant vesicles lead to the inclusion of an organic solvent layer that affects the mechanical and physical characteristics of the membrane. Here we describe the formation of asymmetric giant vesicles that include little organic solvent, and use them to investigate the dynamic responses of lipid molecules in the vesicle membrane. We formed the giant vesicles via the inhomogeneous break-up of a lipid microtube generated by applying a jet flow to an asymmetric planar lipid bilayer. The asymmetric giant vesicles showed a lipid flip-flop behaviour in the membrane, superficially similar to the lipid flip-flop activity observed in apoptotic cells. In vitro synthesis of membrane proteins into the asymmetric giant vesicles revealed that the lipid asymmetry in bilayer membranes improves the reconstitution ratio of membrane proteins. Our asymmetric giant vesicles will be useful in elucidating lipid-lipid and lipid-membrane protein interactions involved in the regulation of cellular functions.
authors.affiliation: Artificial Cell Membrane Systems Group, Kanagawa Academy of Science and Technology, KSP East 303, 3-2-1 Sakado, Takatsu, Kawasaki, Kanagawa 213-0012, Japan.|Japan Science of Technology Agency, PRESTO, KSP East 303, 3-2-1 Sakado, Takatsu, Kawasaki, Kanagawa 213-0012, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Kamiya
authors.affiliation: Artificial Cell Membrane Systems Group, Kanagawa Academy of Science and Technology, KSP East 303, 3-2-1 Sakado, Takatsu, Kawasaki, Kanagawa 213-0012, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kawano
authors.affiliation: Artificial Cell Membrane Systems Group, Kanagawa Academy of Science and Technology, KSP East 303, 3-2-1 Sakado, Takatsu, Kawasaki, Kanagawa 213-0012, Japan.|Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
authors.forename: Toshihisa
authors.identifier: 0000-0003-1659-2541
authors.initials: T
authors.lastname: Osaki
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University JST ERATO, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Akiyoshi
authors.affiliation: Artificial Cell Membrane Systems Group, Kanagawa Academy of Science and Technology, KSP East 303, 3-2-1 Sakado, Takatsu, Kawasaki, Kanagawa 213-0012, Japan.|Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Takeuchi
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry; D001430:Bacteriocins / Q000737:chemistry; D018031:Connexin 43 / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D010316:Particle Size; D010456:Peptides, Cyclic / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry; D010718:Phosphatidylserines / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D053835:Unilamellar Liposomes / Q000737:chemistry*
chemical_list: D000473:Alkanes; D001430:Bacteriocins; D018031:Connexin 43; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D010456:Peptides, Cyclic; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D012235:Rhodamines; D053835:Unilamellar Liposomes; C000485:cinnamycin; D015060:1,2-Dipalmitoylphosphatidylcholine; C042511:1,2-dioleoylphosphatidylserine; C017251:1,2-oleoylphosphatidylcholine; C012867:decane