Mechanisms of cell fusion

Ahkong, Quet F.; Fisher, Derek; Tampion, W.; Lucy, J. A.

doi:10.1038/253194a0

Cited by 400 publications

(130 citation statements)

References 14 publications

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“…It was thought that fusion might then proceed by interdigitation in the two membranes of aggregated membrane proteins, and the areas of free lipid bilayer arising from protein aggregation were not considered to be of any significance. Shortly afterwards it was suggested that fusion may occur in the areas of membrane that are free from integral proteins [6]. This is consistent with the ability of lipid vesicles to fuse readily under appropriate conditions, and also with many [7-111 but not all [12] observations on the fusion of biomembranes.…”

Section: Aggregation Of Integral Proteinssupporting

confidence: 52%

Do hydrophobic sequences cleaved from cellular polypeptides induce membrane fusion reactions in vivo?

Lucy

1984

FEBS Letters

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The concept that a direct interaction between Ca2+ and phospholipids is a major factor in membrane fusion reactions is questioned. Attention is drawn to a number of findings on associations between fusion and the proteolysis of membrane proteins. It is proposed that hydrophobic polypeptides, which are functionally comparable to the fusogenic proteins of certain viruses but which are produced in cells by the endogenous proteolysis of membrane and cellular proteins, may induce membrane fusion reactions in vivo.

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Section: Aggregation Of Integral Proteinssupporting

confidence: 52%

Do hydrophobic sequences cleaved from cellular polypeptides induce membrane fusion reactions in vivo?

Lucy

1984

FEBS Letters

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“…No change in size or number of liposomes was observed when incubated at 37°C for several minutes or even when stored over night at about 4°C. This is despite of the high content of lysolecithin, which has been reported to in du ce fusion of erythrocytes [34] and liposomes [35] or alternatively to induce exchange diffusion [36].…”

Section: Fusion 01 Liposomesmentioning

confidence: 98%

Membrane fusion of secretory vesicles and liposomes Two different types of fusion

Ekerdt

Dahl²,

Gratzl³

1981

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Secretory vesieles isolated from adrenal medulla were found to fuse in vitro in response to incubation with Ca 2 +. Intervesicular fusion was detected by electron microscopy and was indicated by the appearance of twinned vesieies in freeze-fractured suspensions of vesieles and in thin-sectioned pellet. Two types of fusion could be distinguished: Type I, occurring between 10-7 M and 10-4 M Ca 2 +, was specific for ea 2 +, was inhibited by other divalent cations and was abolished by pretreatment of vesieles with glutaraldehyde, neuraminidase or trypsin. Fusion type I was linear with temperature. A second type of intervesicular fusion was elicited by Ca 2 + in concentrations higher than 2.5 mM and was morphologically characterized by multiple fusions of secretory vesicles. This type of fusion was found to be similar to fusion of liposomes prepared from the membrane lipids of adrenal medullary secretory vesieles: ea 2 + could be replaced by other divalent cations, the effect of different divalent cations was additive and pretreatments attacking membrane proteins were ineffective. Fusion type 11 of intact secretory vesieies as weil as liposome fusion was discontinuous with temperature. Liposome fusion could be detected within 35 ms and persisted for 180 min. Using liposomes containing defined Ca 2 + concentrations we have not found a major influence of Ca 2 + asymmetry on fusion. Incorporation of the ganglioside GM 3 , which is present in the membranes of intact adrenal medullary secretory vesicles did not change the properties of liposomes fusion. Using a Ca 2 +-selective electrode we have identified in secretory vesiele membranes both high affinity binding sites for Ca 2 + (/(} = 1.6 . 10-6 M) and low affinity sites (/(} = 1.2· 10-4 M).

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“…The distributions of these particles at sites of membrane fusion, reviewed in [ 11, variously support the hypothesis that fusion proceeds by the interdigitation of aggregated membrane proteins [2], or the alternative idea that fusion involves the intermingling of membrane lipids after the emergence of protein-free areas of lipid bilayer following protein aggregation [3].…”

Section: Introductionmentioning

confidence: 99%