Studies on the mechanism of membrane fusion. Role of head-group composition in calcium- and magnesium-induced fusion of mixed phospholipid vesicles.

来自 dx.doi.org

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阅读量：

102

作者：

N Düzgünes，J Wilschut，R Fraley，D Papahadjopoulos

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摘要：

We have investigated the contribution of various phospholipids to membrane fusion induced by divalent cations. Fusion was followed by means of a new fluorescence assay monitoring the mixing of internal aqueous contents of large (0.1 μm diameter) unilamellar liposomes. The rate and extent of fusion induced by Ca 2+ in mixed phosphatidylserine/phosphatidylcholine vesicles were lower compared to those in pure phosphatidylserine vesicles. The presence of 50% phosphatidylcholine completely inhibited fusion, although the vesicles aggregated upon Ca 2+ addition. When phosphatidylserine was mixed with phosphatidylethanolamine, however, rapid fusion could be induced by Ca 2+ even in mixtures that contained only 25% phosphatidylserine. Phosphatidylethanolamine also facilitated fusion by Mg 2+ which could not fuse pure phosphatidylserine vesicles. In phosphatidylserine/phosphatidylethanolamine/phosphatidylcholine mixtures, in which the phosphatidylcholine content was kept at 25%, phosphatidylethanolamine could not substitute for phosphatidylserine, and the fusogenic capacity of Mg 2+ was abolished by the presence of merely 10% phosphatidylcholine. The initial rate of release of vesicle contents was slower than the rate of fusion in all the mixtures used. The presence of phosphate effected a considerable decrease in the threshold concentration of Ca 2+ and also enhanced

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关键词：

EGTA ethylene glycol bis(β- aminoethyl ether)-N,N′- tetraacetic acid ethylene glycol bis(β- aminoethyl ether)-N,N′- tetraacetic acid Tes tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid

DOI：

10.1016/0005-2736(81)90148-6

被引量：

648

年份：

1981