Fusion of negatively charged liposomes with clathrin-uncoated vesicles.
The interaction of lipid vesicles with uncoated vesicles from bovine brain has been studied by fluorescence energy transfer between fluorescent lipid analogs (NBD-PE, Rh-DOPE), by loss of fluorescence self-quenching (NBD-PE, carboxyfluorescein) and by freeze-fracture electron microscopy. The fluorescence techniques monitor the mixing of membranous lipids and the induced release of encapsulated material. The results demonstrate a mixing of the negatively charged lipid (PA, PS) vesicles with the uncoated vesicles. In parallel with the lipid mixing a release of intravesicularly encapsulated material takes place. Lipid vesicles composed of zwitterionic lipids (PC, DOPC, PC:PE) do not specifically interact with uncoated vesicles. The electron micrographs reveal single fusion events. Studies on the kinetics are consistent with a fusional mechanism of the negatively charged lipid vesicles with uncoated vesicles.
D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D002417:Cattle; D002458:Cell Fractionation; D003034:Coated Pits, Cell-Membrane / Q000502:physiology* / Q000648:ultrastructure; D004563:Electrochemistry; D011992:Endosomes / Q000502:physiology*; D004735:Energy Transfer; D005452:Fluoresceins; D005456:Fluorescent Dyes; D005614:Freeze Fracturing; D007700:Kinetics; D008051:Lipid Bilayers / Q000378:metabolism; D008081:Liposomes / Q000378:metabolism*; D008561:Membrane Fusion; D008854:Microscopy, Electron; D010712:Phosphatidic Acids / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D012235:Rhodamines / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D005452:Fluoresceins; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D008081:Liposomes; C053685:N-(lissamine rhodamine B sulfonyl)-1,2-dioleoylphosphatidylethanolamine; D010712:Phosphatidic Acids; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D012235:Rhodamines; C024098:6-carboxyfluorescein; C042077:N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)phosphatidylethanolamine