TY - JOUR
T1 - Functional implications of tyrosine protein phosphorylation in platelets. Simultaneous studies with different agonists and inhibitors
AU - Bachelot, C.
AU - Cano, E.
AU - Grelac, F.
AU - Saleun, S.
AU - Druker, B.
AU - Levy-Toledano, S.
AU - Fischer, S.
AU - Rendu, F.
PY - 1992
Y1 - 1992
N2 - During activation of platelets by agonists, a number of proteins become phosphorylated at tyrosine residues. Using immunoblotting with a monoclonal anti-phosphotyrosine antibody, we have compared the different phosphotyrosine-protein (PTP) profiles of platelets stimulated with thrombin, collagen, ADP, arachidonic acid, phorbol myristate acetate and P256, an anti-glycoprotein-Ilb IIIa (GPIIb IIIa) monoclonal antibody (mAb). Only a few PTPs were observed in resting platelets, of molecular masses 130, 64, 56-60 and 36 kDa. After stimulation by different agonists these proteins were more intensely phosphorylated and additional PTPs appeared with molecular masses of 170, 150, 140, 120, 105/97 (doublet), 85, 80, 75 and 45 kDa. The kinetics of phosphorylation differed from one agonist to another, but no significant differences in the overall patterns were detected, except in presence of ADP and P256-F(ab')2, which induced only the additional tyrosine phosphorylation of the 64 kDa protein and to a lesser extent that of a 75 kDa protein. The use of various agonists and the inhibitors (staurosporine, ajoene and RGDS) permitted a better characterization of the relationship between the different steps of activation and phosphorylation on tyrosine residues. The studies suggest the following conclusions: (i) stimulation of tyrosine phosphorylation occurs after activation of protein kinase C; (ii) there is a relationship between ligand binding to GPIIb IIIa and the tyrosine phosphorylation of the 64 kDa protein. and (iii) there is a close relationship between PTP formation and the intensity of platelet activation and aggregation.
AB - During activation of platelets by agonists, a number of proteins become phosphorylated at tyrosine residues. Using immunoblotting with a monoclonal anti-phosphotyrosine antibody, we have compared the different phosphotyrosine-protein (PTP) profiles of platelets stimulated with thrombin, collagen, ADP, arachidonic acid, phorbol myristate acetate and P256, an anti-glycoprotein-Ilb IIIa (GPIIb IIIa) monoclonal antibody (mAb). Only a few PTPs were observed in resting platelets, of molecular masses 130, 64, 56-60 and 36 kDa. After stimulation by different agonists these proteins were more intensely phosphorylated and additional PTPs appeared with molecular masses of 170, 150, 140, 120, 105/97 (doublet), 85, 80, 75 and 45 kDa. The kinetics of phosphorylation differed from one agonist to another, but no significant differences in the overall patterns were detected, except in presence of ADP and P256-F(ab')2, which induced only the additional tyrosine phosphorylation of the 64 kDa protein and to a lesser extent that of a 75 kDa protein. The use of various agonists and the inhibitors (staurosporine, ajoene and RGDS) permitted a better characterization of the relationship between the different steps of activation and phosphorylation on tyrosine residues. The studies suggest the following conclusions: (i) stimulation of tyrosine phosphorylation occurs after activation of protein kinase C; (ii) there is a relationship between ligand binding to GPIIb IIIa and the tyrosine phosphorylation of the 64 kDa protein. and (iii) there is a close relationship between PTP formation and the intensity of platelet activation and aggregation.
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U2 - 10.1042/bj2840923
DO - 10.1042/bj2840923
M3 - Article
C2 - 1622407
AN - SCOPUS:0026770575
SN - 0264-6021
VL - 284
SP - 923
EP - 928
JO - Biochemical Journal
JF - Biochemical Journal
IS - 3
ER -