Parameters affecting the fusion of unilamellar phospholipid vesicles within planar bilayer membranes

F. S. Cohen, M. H. Akabas, J. Zimmerberg, A. Finkelstein

Research output: Contribution to journalArticle

85 Scopus citations

Abstract

It was previously shown (Cohen, F.S., J. Zimmerberg, and A. Finkelstein, 1980, J. Gen. Physiol., 75:251-270) that multilamellar phospholipid vesicles can fuse with decane-containing phospholipid bilayer membranes. An essential requirement for fusion was an osmotic gradient across the planar membrane, with the vesicle-containing (cis) side hyperosmotic with respect to the opposite (trans) side. We now report that unilamellar vesicles will fuse with 'hydrocarbon-free' membranes subject to these same osmotic conditions. Thus the same conditions that apply to fusion of multilamellar vesicles with planar bilayer membranes also apply to fusion of unilamellar vesicles with these membranes, and hydrocarbon is not required for the fusion process. If the vesicles and/or planar membrane contain negatively charged lipids, divalent cation (~ 15 mM Ca++) is required in the cis compartment (in addition to the osmotic gradient across the membrane) to obtain substantial fusion rates. On the other hand, vesicles made from uncharged lipids readily fuse with planar phosphatidylethanolamine planar membrane in the near absence of divalent cation with just an osmotic gradient. Vesicles fuse much more readily with phosphatidylethanolamine-containing than with phosphatidylcholine-containing planar membranes. Although hydrocarbon (decane) is not required in the planar membrane for fusion, it does affect the rate of fusion and causes the fusion process to be dependent on stirring in the cis compartment.

Original languageEnglish (US)
Pages (from-to)1054-1062
Number of pages9
JournalJournal of Cell Biology
Volume98
Issue number3
DOIs
StatePublished - 1984

ASJC Scopus subject areas

  • Cell Biology

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