TY - JOUR
T1 - Thermally-induced aggregation and fusion of protein-free lipid vesicles
AU - Ibarguren, M.
AU - Bomans, P.H.H.
AU - Ruiz-Mirazo, K.
AU - Frederik, P.M.
AU - Alonso, A.
AU - Goñi, F.M.
PY - 2015/12/1
Y1 - 2015/12/1
N2 - Membrane fusion is an important phenomenon in cell biology and pathology. This phenomenon can be modeled using vesicles of defined size and lipid composition. Up to now fusion models typically required the use of chemical (polyethyleneglycol, cations) or enzymatic catalysts (phospholipases). We present here a model of lipid vesicle fusion induced by heat. Large unilamellar vesicles consisting of a phospholipid (dioleoylphosphatidylcholine), cholesterol and diacylglycerol in a 43:57:3mol ratio were employed. In this simple system, fusion was the result of thermal fluctuations, above 60°C. A similar system containing phospholipid and cholesterol but no diacylglycerol was observed to aggregate at and above 60°C, in the absence of fusion. Vesicle fusion occurred under our experimental conditions only when 31P NMR and cryo-transmission electron microscopy of the lipid mixtures used in vesicle preparation showed non-lamellar lipid phase formation (hexagonal and cubic). Non-lamellar structures are probably the result of lipid reassembly of the products of individual fusion events, or of fusion intermediates. A temperature-triggered mechanism of lipid reassembly might have occurred at various stages of protocellular evolution.
AB - Membrane fusion is an important phenomenon in cell biology and pathology. This phenomenon can be modeled using vesicles of defined size and lipid composition. Up to now fusion models typically required the use of chemical (polyethyleneglycol, cations) or enzymatic catalysts (phospholipases). We present here a model of lipid vesicle fusion induced by heat. Large unilamellar vesicles consisting of a phospholipid (dioleoylphosphatidylcholine), cholesterol and diacylglycerol in a 43:57:3mol ratio were employed. In this simple system, fusion was the result of thermal fluctuations, above 60°C. A similar system containing phospholipid and cholesterol but no diacylglycerol was observed to aggregate at and above 60°C, in the absence of fusion. Vesicle fusion occurred under our experimental conditions only when 31P NMR and cryo-transmission electron microscopy of the lipid mixtures used in vesicle preparation showed non-lamellar lipid phase formation (hexagonal and cubic). Non-lamellar structures are probably the result of lipid reassembly of the products of individual fusion events, or of fusion intermediates. A temperature-triggered mechanism of lipid reassembly might have occurred at various stages of protocellular evolution.
KW - Cholesterol
KW - Fusion
KW - Non-lamellar phases
KW - Thermal fluctuations
UR - http://www.scopus.com/inward/record.url?scp=84943746297&partnerID=8YFLogxK
U2 - 10.1016/j.colsurfb.2015.09.047
DO - 10.1016/j.colsurfb.2015.09.047
M3 - Article
C2 - 26454544
AN - SCOPUS:84943746297
VL - 136
SP - 545
EP - 552
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
SN - 0927-7765
ER -