Duality of plasmin effect on cytosolic free calcium in human platelets
| Autor: | Masayuki Kimura, K. Nakamura, J. W. Fenton, T. T. Andersen, Abraham Aviv |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Blood Platelets
Male Fura-2 Physiology Plasmin chemistry.chemical_compound Cytosol Thrombin Thrombin receptor Cyclic AMP medicine Humans Fibrinolysin Phosphorylation Tyrosine Cyclic GMP Protein Kinase C Protein kinase C Tyrosine phosphorylation Cell Biology Protein-Tyrosine Kinases Peptide Fragments chemistry Biochemistry Biophysics Calcium Receptors Thrombin circulatory and respiratory physiology medicine.drug |
| Zdroj: | American Journal of Physiology-Cell Physiology. 268:C958-C967 |
| ISSN: | 1522-1563 0363-6143 |
| Popis: | Plasmin caused a modest and gradual increase in platelet cytosolic Ca2+, mediated through both Ca2+ mobilization and external Ca2+ entry. This response was associated with accelerated Ca2+ extrusion and protein tyrosine phosphorylation. Plasmin-enhanced external Ca2+ entry and Ca2+ extrusion (but not Ca2+ mobilization) were attenuated by the tyrosine kinase inhibitor, genistein. Plasmin inhibited the thrombin-evoked increase in cytosolic Ca2+ and also inhibited the Ca2+ response to the tethered peptide TRAP-6 of the thrombin receptor. Furthermore, plasmin inhibited the binding of 125I-labeled alpha-thrombin to platelets. The inhibitory effect of plasmin on the thrombin response shared some characteristics with the effect of protein kinase C stimulators but was not reversed by protein kinase C inhibitors. Plasmin did not change platelet cyclic nucleotides. These results suggest a dual effect of plasmin. Plasmin produces a small rise in platelet cytosolic Ca2+ and a tyrosine kinase-dependent enhancement of Ca2+ turnover (external Ca2+ influx and Ca2+ efflux). However, it also attenuates the thrombin-evoked cytosolic Ca2+ response by blocking Ca2+ mobilization and slowing the rate of external Ca2+ influx. The latter feature would result in a plasmin-induced inhibition of thrombogenesis. |
| Databáze: | OpenAIRE |
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