Phospholipase D activity facilitates Ca2+-induced aggregation and fusion of complex liposomes
| Autor: | S. French, A T Transue, Donna M. Harsh, James E. Smolen, R. C. Brower, Ronald J. Hessler, R A Blackwood |
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| Rok vydání: | 1997 |
| Předmět: |
Physiology
Phospholipid Phosphatidic Acids Membrane Fusion Cell Degranulation Choline chemistry.chemical_compound Phosphatidylcholine Phospholipase D Phospholipase D activity Phospholipids Annexin A1 Liposome Hydrolysis Lipid bilayer fusion Drug Synergism Cell Biology Phosphatidic acid Streptomyces Enzyme Activation chemistry Biochemistry Liposomes Biophysics Neutrophil degranulation lipids (amino acids peptides and proteins) Calcium |
| Zdroj: | The American journal of physiology. 272(4 Pt 1) |
| ISSN: | 0002-9513 |
| Popis: | Phospholipase D (PLD) activation in stimulated neutrophils results in the conversion of membrane phosphatidylcholine (PC) to phosphatidic acid (PA). This change in membrane phospholipid composition has two potentially positive effects on degranulation. It 1) replaces a nonfusogenic phospholipid with a fusogenic one and 2) increases the potential for interactions between membranes and the annexins. Modeling neutrophil degranulation, we examined the effect of PLD (Streptomyces chromofuscus) hydrolysis on the aggregation and fusion of liposomes in the presence and absence of annexin I. We found that PLD-mediated conversion of PC to PA lowered the [Ca2+] required for fusion. Annexin I increased the rate of fusion in the presence of PA, although it did not lower threshold [Ca2+], which remained above the physiological range. However, after hydrolysis by PLD, annexin I lowered the [Ca2+] required for aggregation by almost three orders of magnitude, to near physiological concentrations. These studies indicate that the activation of PLD and the production of PA may play a role in annexin-mediated membrane-membrane apposition. |
| Databáze: | OpenAIRE |
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