title: Multibudded tubules formed by COPII on artificial liposomes.
abstract: COPII-coated vesicles form at the endoplasmic reticulum for cargo transport to the Golgi apparatus. We used in vitro reconstitution to examine the roles of the COPII scaffold in remodeling the shape of a lipid bilayer. Giant Unilamellar Vesicles were examined using fast confocal fluorescence and cryo-electron microscopy in order to avoid separation steps and minimize mechanical manipulation. COPII showed a preference for high curvature structures, but also sufficient flexibility for binding to low curvatures. The COPII proteins induced beads-on-a-string-like constricted tubules, similar to those previously observed in cells. We speculate about a mechanical pathway for vesicle fission from these multibudded COPII-coated tubules, considering the possibility that withdrawal of the Sar1 amphipathic helix upon GTP hydrolysis leads to lipid bilayer destabilization resulting in fission.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA; HALOmem, University of Halle, Kurt-Mothes-Str. 3, 06120 Halle, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Bacia
authors.forename: Eugene
authors.initials: E
authors.lastname: Futai
authors.forename: Simone
authors.initials: S
authors.lastname: Prinz
authors.forename: Annette
authors.initials: A
authors.lastname: Meister
authors.forename: Sebastian
authors.initials: S
authors.lastname: Daum
authors.forename: Daniela
authors.initials: D
authors.lastname: Glatte
authors.forename: John A G
authors.initials: JA
authors.lastname: Briggs
authors.forename: Randy
authors.initials: R
authors.lastname: Schekman
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry; D022181:COP-Coated Vesicles / Q000737:chemistry* / Q000648:ultrastructure*; D022081:Cell Surface Extensions / Q000737:chemistry* / Q000648:ultrastructure*; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008422:Materials Testing; D008560:Membrane Fluidity
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes