title: Thrombin-induced Ca2+ influx and protein tyrosine phosphorylation in endothelial cells is inhibited by herbimycin A.
abstract: During endothelial cell activation, alpha-thrombin elicits both Ca2+ release from internal stores and influx of external Ca2+ across the plasma membrane. The mechanisms of alpha-thrombin-induced Ca2+ entry into endothelial cells are unclear. Therefore, effects of the specific tyrosine kinase inhibitor herbimycin A on protein tyrosine phosphorylation and on intracellular Ca2+ transients were studied in alpha-thrombin-stimulated human umbilical vein endothelial cells. alpha-Thrombin caused significant tyrosine phosphorylation of mainly two proteins and evoked typical biphasic changes of free cytosolic Ca2+ concentration. We show that 24 h pretreatment with herbimycin A inhibited alpha-thrombin-induced endothelial protein tyrosine phosphorylation. Moreover, herbimycin A significantly attenuated alpha-thrombin-induced Ca2+ influx but not release from internal stores. The data suggest that protein tyrosine phosphorylation by alpha-thrombin is involved in the regulation of alpha-thrombin-induced Ca2+ influx into endothelial cells.
authors.affiliation: Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, University of Munich, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Kruse
authors.forename: E V
authors.initials: EV
authors.lastname: Negrescu
authors.forename: P C
authors.initials: PC
authors.lastname: Weber
authors.forename: W
authors.initials: W
authors.lastname: Siess
mesh_terms: D016227:Benzoquinones; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D017136:Ion Transport / Q000187:drug effects; D047029:Lactams, Macrocyclic; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology*; D017828:Rifabutin / Q000031:analogs & derivatives; D013917:Thrombin / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D016227:Benzoquinones; D047029:Lactams, Macrocyclic; D011809:Quinones; D017828:Rifabutin; D014443:Tyrosine; C020754:herbimycin; D011505:Protein-Tyrosine Kinases; D013917:Thrombin; D002118:Calcium