Comparison between the loss of platelet membrane asymmetry, microvesiculation and the tyrosine phosphorylation of proteins.
Platelet activation by agents such as the Ca2+-ionophore A23187 or Ca2+-ATPase inhibitors leads to the generation of a procoagulant surface and the formation of microparticles. These responses are late events of platelet activation and readily detected by flow cytometry using annexin V-FITC as an aminophospholipid probe. One Ca2+-ATPase inhibitor, 2,5-di-(tertbutyl)-1,4-benzohydroquinone induced aminophospholipid exposure without microparticle formation. Previous work has shown that microparticle formation is strictly linked to the activation of calpain, a thiol-protease that modifies the platelet cytoskeleton and some signal transduction enzymes. We now report how the detection of platelet tyrosine phosphorylation by western-blotting clearly shows that when platelet activation and aminophospholipid exposure are accompanied by microparticle formation there is a decrease in the tyrosine phosphorylation of proteins.
Pasquet
J M
JM
UMR 5533 CNRS, Hôpital Cardiologique du Haut-Leveque, Pessac, France.
Dachary-Prigent
J
J
Nurden
A T
AT
D001792:Blood Platelets / Q000502:physiology*; D006801:Humans; D008566:Membranes / Q000502:physiology; D010766:Phosphorylation; D015539:Platelet Activation / Q000502:physiology; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism* / Q000502:physiology; D014443:Tyrosine / Q000378:metabolism*
D010980:Platelet Membrane Glycoproteins; D014443:Tyrosine