Abstract
Although exocytosis is triggered by a rise in intracellular levels of Ca2+, it is not known how Ca2+ produces this effect. Because Ca2+ regulates so many cellular functions, it is difficult to establish what role any one of these plays in exocytosis. An approach for determining the mechanisms underlying fusion is to study those aspects of the process that can be attributed solely to phospholipid bilayer interactions, independent of membrane proteins and cytoplasmic factors. Thus, considerable effort has gone into studying fusion between artificial phospholipid bilayer membranes, with most of this effort directed to fusion between vesicles [8,9,11]. On the other hand, we have studied the fusion of phospholipid vesicles to planar phospholipid bilayer membranes. Here, we describe the physical principles that govern fusion in this system and discuss their possible applicability to fusion and exocytosis as they occur biologically.
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References
Akabas, M. H.; Cohen, F. S.; Finkelstein, A. Separation of the osmotically driven fusion event from vesicle- planar membrane attachment in a model system for exocytosis. J. Cell Biol. 98: 1063–1071, 1984.
Berl, S.; Psuszkin, S.; Nicklas, W. J. Actomyosin-like protein in brain. Science 179: 441–446, 1973.
Cohen, F. S.; Zimmerberg, J.; Finkelstein, A. Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. II. Incorporation of a vesicular membrane marker into the planar membrane. J. Gen. Physiol. 75:251–270, 1980.
Cohen, F. S.; Akabas, M. H.; Finkelstein, A. Osmotic swelling of phospholipid vesicles causes them to fuse with a planar phospholipid bilayer membrane. Science 217: 458–460, 1982.
Creutz, C. E.; Pazoles, C. J.; Pollard, H. B. Identification and purification of an adrenal medullary protein (synexin) that causes calcium-dependent aggregation of isolated chromaffin granules. J. Biol. Chem. 253: 2858–2866, 1978.
Dean, P. M. Exocytosis modelling: An electrostatic function for calcium in stimulus-secretion coupling. J. Theor. Biol. 54: 289–308, 1975.
Howell, S. L.; Tyhurst, M. Microtubules, microfilaments, and insulin secretion. Diabetologia 22: 301–308, 1982.
Kendall, D. A.; MacDonald, R. C. A fluorescence assay to monitor vesicle fusion and lysis. J. Biol. Chem. 257: 13892–13895, 1982.
9Miller, C.; Arvan, P.; Telford, J. N.; Racker, E. Ca2 + -induced fusion of proteoliposomes: Dependence on transmembrane osmotic gradients. J. Membr. Biol. 30: 271–282, 1976.
Schindler, H.; Rosenbusch, J. P. Matrix protein from Escherichia coli outer membranes forms voltage- controlled channels in lipid bilayers. Proc. Natl. Acad. Sci. USA 75: 3751–3755, 1978.
Wilschut, J.; Papahadjopolous, D. Ca2+-induced fusion of phospholipid vesicles monitored by mixing of aqueous contents. Nature (London) 281: 690–692, 1979.
Zimmerberg, J.; Cohen, F. S.; Finkelstein, A. Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. I. Discharge of vesicular contents across the planar membrane. J. Gen. Physiol. 75: 241–250, 1980.
Zimmerberg, J.; Cohen, F. S.; Finkelstein, A. Micromolar Ca2+ stimulates fusion of lipid vesicles with planar bilayers containing a calcium-binding protein. Science 210: 906–908, 1980.
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© 1985 Plenum Press, New York
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Cohen, F.S., Akabas, M.H., Finkelstein, A. (1985). The Role of Calcium and Osmosis in Membrane Fusion. In: Rubin, R.P., Weiss, G.B., Putney, J.W. (eds) Calcium in Biological Systems. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-2377-8_14
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DOI: https://doi.org/10.1007/978-1-4613-2377-8_14
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