Effects of jararaca GPIb-BP on PTP of whole cell lysates (A) and p72syk activation (B) induced by botrocetin-vWF. Platelets were incubated with or without 10 μg/mL of jararaca GPIb-BP for 5 minutes and then activated with 3 μg/mL of botrocetin and 10 μg/mL of vWF for the indicated time intervals. For PTP analysis, reactions were terminated with Laemmli SDS buffer, and samples were Western-blotted using antiphosphotyrosine MoAb, 4G10. For analysis of p72syk autophosphorylation, reactions were terminated by adding lysis buffer. p72syk was immunoprecipitated with anti-p72syk MoAb, and the sample was Western-blotted using antiphosphotyrosine MoAb, 4G10. (A) PTP in whole cell lysates. The arrowhead indicates 64-kD PTP. (B) p72syk autophosphorylation. The arrowhead represents the band presumably from IgG heavy chains. The data are representative of three experiments.
