The hemifusion intermediate and its conversion to complete fusion: regulation by membrane composition.
To fuse, membranes must bend. The energy of each lipid monolayer with respect to bending is minimized at the spontaneous curvature of the monolayer. Two lipids known to promote opposite spontaneous curvatures, lysophosphatidylcholine and arachidonic acid, were added to different sides of planar phospholipid membranes. Lysophosphatidylcholine added to the contacting monolayers of fusing membranes inhibited the hemifusion we observed between lipid vesicles and planar membranes. In contrast, fusion pore formation depended upon the distal monolayer of the planar membrane; lysophosphatidylcholine promoted and arachidonic acid inhibited. Thus, the intermediates of hemifusion and fusion pores in phospholipid membranes involve different membrane monolayers and may have opposite net curvatures, Biological fusion may proceed through similar intermediates.
Laboratory of Theoretical and Physical Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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L
Chernomordik
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A
Chanturiya
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Green
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J
Zimmerberg
D016718:Arachidonic Acid / Q000737:chemistry*; D007700:Kinetics; D008051:Lipid Bilayers; D008244:Lysophosphatidylcholines / Q000737:chemistry*; D008561:Membrane Fusion; D008954:Models, Biological; D008968:Molecular Conformation; D010713:Phosphatidylcholines / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D012710:Serum Albumin, Bovine; D013329:Structure-Activity Relationship
D008051:Lipid Bilayers; D008244:Lysophosphatidylcholines; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D012710:Serum Albumin, Bovine; D016718:Arachidonic Acid; C031730:3-dodecanoylpropanediol-1-phosphorylcholine