Diacylglycerol Elevations in Control Platelets are Unaccompanied by Pleckstrin Phosphorylation. Implications for the Role of Diacylglycerol in Platelet Activation
| Autor: | Miriam H. Fukami, Holm Holmsen |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Blood Platelets
Hot Temperature Biology In Vitro Techniques Biochemistry Diglycerides chemistry.chemical_compound Thrombin medicine Humans Protease-activated receptor Platelet Platelet activation Phosphorylation Protein kinase C Diacylglycerol kinase Blood Proteins Phosphatidic acid Phosphoproteins Platelet Activation Pleckstrin homology domain Kinetics chemistry lipids (amino acids peptides and proteins) medicine.drug |
| Zdroj: | European Journal of Biochemistry. 228:579-586 |
| ISSN: | 1432-1033 0014-2956 |
| DOI: | 10.1111/j.1432-1033.1995.tb20297.x |
| Popis: | Several laboratories have reported that diacylglycerol levels in human platelets (approximately 100 pmol/10(9) platelets) increased severalfold in response to 0.5-1 U/ml thrombin. We report here fluctuations in diacylglycerol mass in control platelets, the magnitude of which were 60-90% of that measured in platelets treated with 0.2-0.5 U/ml of thrombin. These control platelets were not activated by such criteria as absence of aggregation, secretion, phosphatidic acid production and phosphorylation of the protein kinase C substrate, pleckstrin. Thrombin treatment evoked all of the above responses. Analysis of the diacylglycerol molecular species by reverse-phase HPLC of the dimethylated, phosphorylated derivatives showed that all of the molecular species that were present in control platelets were also present in thrombin-treated platelets. Most of the species appeared to fluctuate at random in control platelets with the exception of 1-stearoyl-2-arachidonoyl-sn-glycerol which was more or less stable and increased severalfold over control values only upon thrombin treatment. Furthermore, only this species accumulated as [32P]phosphorylated PtdOH in thrombin-treated platelets prelabelled with [32P]Pi. Our findings show that, in platelets, elevation of diacylglycerol molecular species other than the 1-stearoyl-2-arachidonoyl species occurs, but these changes are not necessarily linked to activation of protein kinase C as measured by pleckstrin phosphorylation which was observed only upon elevation of 1-stearoyl-2-arachidonoyl-sn-glycerol. |
| Databáze: | OpenAIRE |
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