Thrombin treatment induces rapid changes in tyrosine phosphorylation in platelets.
We previously demonstrated that platelets express high levels of the tyrosine protein kinase pp60c-src. By a quantitative immunoblot assay, it is shown in this report that pp60c-src represents 0.2-0.4% of total platelet protein. The expression of high levels of pp60c-src in platelets correlated with high levels of total cell phosphotyrosine. Unstimulated platelets were shown to possess numerous phosphotyrosine-containing proteins by immunoblot analysis using antibodies that specifically recognize phosphotyrosine residues. To examine whether the pattern of phosphotyrosine-containing proteins changes upon platelet activation, lysates from thrombin- and phorbol ester-treated platelets were subjected to immunoblot analysis. Novel phosphotyrosine-containing proteins were detected within seconds following platelet stimulation. These results suggest that tyrosine phosphorylation, perhaps mediated by pp60c-src, may be involved in events associated with platelet activation.
Golden
A
A
Department of Microbiology, State University of New York, Stony Brook 11794.
Brugge
J S
JS
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology*; D002460:Cell Line; D006801:Humans; D015151:Immunoblotting; D066298:In Vitro Techniques; D010766:Phosphorylation; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000097:blood*; D011518:Proto-Oncogene Proteins / Q000097:blood*; D016392:Proto-Oncogene Proteins pp60(c-src); D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000502:physiology*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000097:blood
D011518:Proto-Oncogene Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D013917:Thrombin; D013755:Tetradecanoylphorbol Acetate