Organization and role of platelet membrane phospholipids as studied with purified phospholipases

1979 ◽  
Vol 9 (4) ◽  
pp. 400-406 ◽  
Author(s):  
H. Chap ◽  
B. Perret ◽  
G. Mauco ◽  
M. F. Simon ◽  
L. Douste-Blazy
Keyword(s):  
Platelet Membrane ◽  
Membrane Phospholipids

Organization and role of platelet membrane phospholipids as studied with phospholipases A2 from various venoms and phospholipases C from bacterial origin

Toxicon ◽  
1982 ◽  
Vol 20 (1) ◽  
pp. 291-298 ◽  
Author(s):  
H. Chap ◽  
B. Perret ◽  
G. Mauco ◽  
M. Plantavid ◽  
F. Laffont ◽  
...  
Keyword(s):  
Platelet Membrane ◽  
Membrane Phospholipids ◽  
Phospholipases A2 ◽  
Bacterial Origin

Role of Platelet Membrane Glycoproteins and Von Willebrand Factor in Adhesion of Platelets to Subendothelium and Collagen

1987 ◽  
Vol 516 (1 Blood in Cont) ◽  
pp. 52-65 ◽  
Author(s):  
KJELL S. SAKARIASSEN ◽  
EDITH FRESSINAUD ◽  
JEAN-PIERRE GIRMA ◽  
DOMINIQUE MEYER ◽  
HANS R. BAUMGARTNER
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Membrane ◽  
Membrane Glycoproteins ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Adhesion Of Platelets

Role of phospholipases A2 and C in myocardial ischemic reperfusion injury

1991 ◽  
Vol 260 (3) ◽  
pp. H877-H883 ◽  
Author(s):  
M. R. Prasad ◽  
L. M. Popescu ◽  
I. I. Moraru ◽  
X. K. Liu ◽  
S. Maity ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Ischemic Myocardium ◽  
Lower Amount ◽  
Cellular Injury ◽  
Membrane Phospholipids ◽  
Nonesterified Fatty Acids ◽  
Subcellular Organelles ◽  
Phospholipases A2 ◽  
Rat Hearts

We investigated the role of phospholipase A2 (PLA2) and phospholipase C (PLC) in myocardial phosholipid degradation and cellular injury during reperfusion of ischemic myocardium. For this purpose, isolated rat hearts were perfused with isotopic arachidonic acid to label its membrane phospholipids. Hearts preperfused with antiphospholipase A2 (anti-PLA2) retained a significantly higher amount of radiolabel in phosphatidylcholine and phosphatidylinositol and a corresponding lower amount of radiolabel in lysophosphatidylcholine and nonesterified fatty acids (P less than 0.05) after 30 min of reperfusion following 30 min of normothermic global ischemia compared with hearts preperfused with nonimmune immunoglobulin G. In similar experiments, antiphospholipase C (anti-PLC)-treated hearts were associated with significantly (P less than 0.05) higher radiolabel in all phospholipids and lower radiolabel in diacyglycerol compared with nonimmune immunoglobulin G-treated hearts. Measurement of phospholipase activity in subcellular organelles of these hearts showed decreased PLA2 activity in cytosol, mitochondria, and microsomes of anti-PLA2-treated hearts and decreased PLC activity of microsomes in anti-PLC-treated hearts. Furthermore, both the antiphospholipases attenuated the release of creatine kinase and lactate dehydrogenase into perfusate and increased contractility as well as coronary flow in the reperfused hearts. Results of this study suggest that both PLA2 and PLC are involved in the degradation of phospholipids and cellular injury that occur during reperfusion of ischemic myocardium.

Evolution of the diverse biological roles of inositols

2007 ◽  
Vol 74 ◽  
pp. 223-246 ◽  
Author(s):  
Robert H. Michell
Keyword(s):  
Membrane Trafficking ◽  
Cell Signalling ◽  
Compatible Solutes ◽  
Mirror Image ◽  
Membrane Phospholipids ◽  
Functional Diversification ◽  
Redox Reagent ◽  
Ca2 Channels ◽  
Mycobacterium Spp

Several of the nine hexahydroxycylohexanes (inositols) have functions in Biology, with myo-inositol (Ins) in most of the starring roles; and Ins polyphosphates are amongst the most abundant organic phosphate constituents on Earth. Many Archaea make Ins and use it as a component of diphytanyl membrane phospholipids and the thermoprotective solute di-L-Ins-1,1′-phosphate. Few bacteria make Ins or use it, other than as a carbon source. Those that do include hyperthermophilic Thermotogales (which also employ di-l-Ins-1,1′-phosphate) and actinomycetes such as Mycobacterium spp. (which use mycothiol, an inositol-containing thiol, as an intracellular redox reagent and have characteristic phosphatidylinositol-linked surface oligosaccharides). Bacteria acquired their Ins3P synthases by lateral gene transfer from Archaea. Many eukaryotes, including stressed plants, insects, deep-sea animals and kidney tubule cells, adapt to environmental variation by making or accumulating diverse inositol derivatives as ‘compatible’ solutes. Eukaryotes use phosphatidylinositol derivatives for numerous roles in cell signalling and regulation and in protein anchoring at the cell surface. Remarkably, the diradylglycerol cores of archaeal and eukaryote/bacterial glycerophospholipids have mirror image configurations: sn-2,3 and sn-1,2 respectively. Multicellular animals and amoebozoans exhibit the greatest variety of functions for PtdIns derivatives, including the use of PtdIns(3,4,5)P3 as a signal. Evolutionarily, it seems likely that (i) early archaeons first made myo-inositol approx. 3500 Ma (million years) ago; (ii) archeons brought inositol derivatives into early eukaryotes (approx. 2000 Ma?); (iii) soon thereafter, eukaryotes established ubiquitous functions for phosphoinositides in membrane trafficking and Ins polyphosphate synthesis; and (iv) since approx. 1000 Ma, further waves of functional diversification in amoebozoans and metazoans have introduced Ins(1,4,5)P3 receptor Ca2+ channels and the messenger role of PtdIns(3,4,5)P3.

Phospholipase A2-Induced Platelet Aggregation, Release and Lysis.

1979 ◽  
Author(s):  
D. Heinrich ◽  
S. Beckmann
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Phospholipase A2 ◽  
Platelet Membrane ◽  
Membrane Phospholipids ◽  
Specific Antibodies ◽  
High Concentrations

Activation of washed platelets by exogenous phospholipase A2 (PIA2) purified from crotalus terrificus terrificus venom was studied. Platelets were labeled with 14C-serotonin and 51chromium and resuspended in Tyrode/albumin (TA). With 1-5 μg/ml (final conc.) of crotalus PIA2 no direct platelet alterations were observed. These platelets, however, were refractory to collagen - but not to thrombin or HLA-specific antibodies.10-50 μg/ml crotalus PIA2 rapidly induced platelet aggregation and release 100 μg/ml crotalus PIA2 induced platelet lysis.PIA2-induced platelet alterations were inhibited by EDTA, PGE1, ASS and apyrase. Crotapotin, an acid peptid isolated from crotalus venom, forms complexes with crotalus PIA2 and specifically inhibits PIA2-induced platelet alterations.Conclusion: PIA2-induced platelet alterations are due to liberation of arachidonic acid from phospholipids of the platelet membrane inducing prostaglandin and thromboxane synthesis. With high concentrations of PIA2 breakdown of membrane phospholipids will lead to platelet lysis.

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