Lysolecithin and Cell Fusion

Poole, A. B.; Howell, J. I.; Lucy, J. A.

doi:10.1038/227810a0

Cited by 348 publications

(103 citation statements)

References 26 publications

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“…This finding is in accord with similar inhibitions reported for fusion of intact myoblasts [64,70] as well as for isolated myoblast cell membranes [69]. In contrast, chemically induced fusion of cells was shown to be enhanced by lysolecithin [14,43,60]. 4 Studies with phospholipid membranes have not clarified the effect of lysolecithin on fusion [10,56].…”

Section: Effect Of Various Substances On Ca 2 +-Induced Fusionsupporting

confidence: 81%

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Fusion of secretory vesicles isolated from rat liver

Gratzl

Dahl

1978

J. Membrain Biol.

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Summary. Secretory vesicles isolated from rat liver were found to fuse after exposure to Ca 2 +. Vesicle fusion is characterized by the occurrence of twinned vesicles with a continuous cleavage plane between two vesicles in freeze-fracture electron microscopy. The number of fused vesicles increases with increasing Ca 2 +-concentrations and is half maximal around 10 -6 M. Other divalent cations (Ba 2+, Sr 2+, and Mg 2+) were ineffective. Mg 2+ inhibits Ca2+-induced fusion. Therefore, the fusion of secretory vesicles in vitro is Ca z+ specific and exhibits properties similar to the exocytotic process of various secretory cells.Various substances affecting secretion in vivo (microtubular inhibitors, local anesthetics, ionophores) were tested for their effect on membrane fusion in our system.The fusion of isolated secretory vesicles from liver was found to differ from that of pure phospholipid membranes in its temperature dependence, in its much lower requirement for Ca 2+, and in its Cag+-specificity. Chemical and enzymatic modifications of the vesicle membrane indicate that glycoproteins may account for these differences.Membrane fusion is an essential event in a variety of cell functions such as cell fusion, uptake of extracellular material (endocytosis) and release of cell products (exocytosis). Elucidation of the molecular mechanism of membrane fusion has been hampered by the lack of suitable systems for studying this process. Studies with intact cells have not yielded data which lead to ready interpretation concerning subcellular processes. On the other hand, studies with artificial membranes may be only tangentially related to the fusion of biological membranes.Recently our group investigated the fusion of isolated biological membranes [16,17,31,33,69,74]. We observed that Ca 2+ specifically induces the fusion of isolated secretory vesicles in a buffered sucrose medium.Intervesicular fusion of secretory vesicles, as well as the interaction between the cell membrane and the vesicle membrane, was observed in a variety of secretory cells [2,3,6,18,29,39,53,65]. Douglas [20] showed that in "compound exocytosis" by mast cells an external stimulus initiates fusion between secretory vesicle membranes and the

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Section: Effect Of Various Substances On Ca 2 +-Induced Fusionsupporting

confidence: 81%

“…Lysolecithin has been reported to promote [14,41,60] as well as to inhibit membrane fusion [64,69,70]. We have found that lysolecithin in very low concentration inhibits the CaZ+-specific fusion of isolated secretory vesicles (Table 3).…”

Section: Ejfect Of Various Agentsmentioning

confidence: 69%

Fusion of secretory vesicles isolated from rat liver

Gratzl

Dahl

1978

J. Membrain Biol.

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“…PLA, has been implicated as a control element in the 'synthesis of inflammatory mediators (29), such as eicosanoids, prostaglandins, and platelet-activating factor, providing a pool of free arachidonic acid for the cyclooxygenase pathway. Lysophosphatidylcholine, a product of the PLA,-catalyzed hydrolysis of phospholipids, has been shown to be cytolytic and fusogenic (30). More recently, it has also been reported to be chemotactic for monocytes (31).…”

Section: Discussionmentioning

confidence: 99%

Phospholipase A₂ is a Major Component of the Salt‐Extractable Pool of Matrix Proteins in Adult Human Articular Cartilage

Recklies

White

1991

Arthritis & Rheumatism

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Adult human articular cartilage contains a component with an apparent molecular weight of 16 kd, which is extractable with high ionic strength buffers. This protein, which, in addition to lysozyme, is one of the most prominent components in salt extracts of adult cartilage, is not detectable in cartilage from newborns. We performed N‐terminal sequence analysis to identify the protein. The amino acid sequence obtained for the first 20 residues was identical to that reported for phospholipase A2 (PLA2) from human placenta and human synovial cells. The extractable PLA2 was found to be active. The lack of PLA2 in salt extracts from newborn cartilage observed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis analysis was confirmed by the very low levels of PLA2 activity detectable in these preparations. PLA2 was clearly present in cartilage extracts from an 18‐year‐old subject and a 19‐year‐old subject, suggesting that its accumulation begins at some stage during the adolescent growth period. The enzyme does not appear to be released from cartilage matrix under normal physiologic conditions, and it is possible that the accumulation of PLA2 in maturing cartilage is a result of the decreased matrix turnover associated with the termination of skeletal growth. Whether PLA2 is active in the cartilage matrix, its precise localization, and its effects on the resident chondrocytes remain to be determined.

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“…In phospholipid metabolism lysophospholipids are key intermediates [2]. Under various conditions lysophosphatidylcholines may induce morphological changes in cells [3], facilitate cell fusion [4], cause hemolysis [5--7] and affect the permeability properties of phosphatidylcholine liposomes [5,6,8,9]. The wedge shape of the lysophospholipid molecules suggests a possible common mechanism in these observations.…”

Section: Introductionmentioning

confidence: 99%

Differential miscibility properties of various phosphatidylcholine/lysophosphatidylcholine mixtures

Echteld

Kruijff

Gier

1980

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Lysolecithin and Cell Fusion

Cited by 348 publications

References 26 publications

Fusion of secretory vesicles isolated from rat liver

Fusion of secretory vesicles isolated from rat liver

Phospholipase A₂ is a Major Component of the Salt‐Extractable Pool of Matrix Proteins in Adult Human Articular Cartilage

Differential miscibility properties of various phosphatidylcholine/lysophosphatidylcholine mixtures

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Lysolecithin and Cell Fusion

Cited by 348 publications

References 26 publications

Fusion of secretory vesicles isolated from rat liver

Fusion of secretory vesicles isolated from rat liver

Phospholipase A2 is a Major Component of the Salt‐Extractable Pool of Matrix Proteins in Adult Human Articular Cartilage

Differential miscibility properties of various phosphatidylcholine/lysophosphatidylcholine mixtures

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Phospholipase A₂ is a Major Component of the Salt‐Extractable Pool of Matrix Proteins in Adult Human Articular Cartilage