Leaky vesicle fusion induced by phosphatidylinositol-specific phospholipase C: observation of mixing of vesicular inner monolayers.
Biochemistry
; 39(46): 14012-8, 2000 Nov 21.
Article
en En
| MEDLINE
| ID: mdl-11087348
Large unilamellar vesicles containing phosphatidylinositol (PI), neutral phospholipids, and cholesterol are induced to fuse by the catalytic activity of phosphatidylinositol-specific phospholipase C (PI-PLC). PI cleavage by PI-PLC is followed by vesicle aggregation, intervesicular lipid mixing, and mixing of vesicular aqueous contents. An average of 2-3 vesicles merge into a large one in the fusion process. Vesicle fusion is accompanied by leakage of vesicular contents. A novel method has been developed to monitor mixing of lipids located in the inner monolayers of the vesicles involved in fusion. Using this method, the mixing of inner monolayer lipids and that of vesicular aqueous contents are seen to occur simultaneously, thus giving rise to the fusion pore. Kinetic studies show, for fusing vesicles, second-order dependence of lipid mixing on diacylglycerol concentration in the bilayer. Varying proportions of PI in the liposomal formulation lead to different physical effects of PI-PLC. Specifically, 30-40 mol % PI lead to vesicle fusion, while with 5-10 mol % PI only hemifusion is detected, i.e., mixing of outer monolayer lipids without mixing of aqueous contents. However, when diacylglycerol is included in the bilayers containing 5 mol % PI, PI-PLC activity leads to complete fusion.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fosfolipasas de Tipo C
/
Membrana Dobles de Lípidos
/
Fusión de Membrana
Idioma:
En
Revista:
Biochemistry
Año:
2000
Tipo del documento:
Article
País de afiliación:
España
Pais de publicación:
Estados Unidos