TY - JOUR
T1 - Parameters affecting the fusion of unilamellar phospholipid vesicles within planar bilayer membranes
AU - Cohen, F. S.
AU - Akabas, M. H.
AU - Zimmerberg, J.
AU - Finkelstein, A.
PY - 1984
Y1 - 1984
N2 - 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.
AB - 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.
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U2 - 10.1083/jcb.98.3.1054
DO - 10.1083/jcb.98.3.1054
M3 - Article
C2 - 6699081
AN - SCOPUS:0021364633
SN - 0021-9525
VL - 98
SP - 1054
EP - 1062
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 3
ER -