![Figure 4. MAP kinase inhibition does not block activation of αIIbβ3 by VWF. (Ai) Structure of the novel MEK inhibitor 5-bromo-2-[2-chloro-4-iodo-phenylamino]-N-cyclopropylmethoxy-3,4-difluoro-benzamide (PD184161). (Aii) Human washed platelets (5 × 108/mL) were preincubated for 5 minutes with vehicle (DMSO 0.1%) or the MEK inhibitor PD184161 at the indicated concentration followed by stimulation with thrombin (0.05 IU/mL). Reactions were stopped by addition of equal volumes of sample buffer, and proteins were separated by SDS-PAGE and Western blotted for phosphorylated p42/44 MAP kinase. Blots are representative of 4 experiments. (Bi) Human platelet-rich plasma (3 × 108 platelets/mL) and (ii) human washed platelets (3 × 108 platelets/mL) were preincubated for 5 minutes with vehicle (DMSO 0.1%) or the MEK inhibitor PD184161 (1-10 μM) followed by stimulation with ristocetin (Rist; 1.5 mg/mL) or thrombin (Thr; 0.05 IU/mL). Experiments were conducted in aggregometer cuvettes with stirring at 37°C. Arrows indicate addition of agonist. Traces are representative of 3 experiments.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/103/7/10.1182_blood-2003-09-3319/6/zh80070459270004.jpeg?Expires=1724233399&Signature=0EqUXxh2zUk~JMcPyElREmRJRqs3oeYnsq8oYXnNV7-5gbS-i2AJn2JvjVNQ2~TRTyEA1M5YREctKokhnd~kqSL6FnC5jQyn2k-hNenICWzRYAs43LIaJGGinabEhMogCNCbsaQu-zfMB6ipEvPJzopdPd8SFp0LMXi93wkIBwKxIWnNhFTfBn5vP6rrywRfCZvrcnkOXpBG3CHU-pKrOWxlDkVsQJkhlWiRwq6l7xSZ7Z0mt4tBLPzOPCDTTV-2NOxYLmISVAhnxMsZlF7q0I7Bv84h6wWCEcwCHy9Yn90RpH8NeT7tghhqqJIGtgbgadM-eRAVH3jOz-PvHceHZA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
MAP kinase inhibition does not block activation of αIIbβ3 by VWF. (Ai) Structure of the novel MEK inhibitor 5-bromo-2-[2-chloro-4-iodo-phenylamino]-N-cyclopropylmethoxy-3,4-difluoro-benzamide (PD184161). (Aii) Human washed platelets (5 × 108/mL) were preincubated for 5 minutes with vehicle (DMSO 0.1%) or the MEK inhibitor PD184161 at the indicated concentration followed by stimulation with thrombin (0.05 IU/mL). Reactions were stopped by addition of equal volumes of sample buffer, and proteins were separated by SDS-PAGE and Western blotted for phosphorylated p42/44 MAP kinase. Blots are representative of 4 experiments. (Bi) Human platelet-rich plasma (3 × 108 platelets/mL) and (ii) human washed platelets (3 × 108 platelets/mL) were preincubated for 5 minutes with vehicle (DMSO 0.1%) or the MEK inhibitor PD184161 (1-10 μM) followed by stimulation with ristocetin (Rist; 1.5 mg/mL) or thrombin (Thr; 0.05 IU/mL). Experiments were conducted in aggregometer cuvettes with stirring at 37°C. Arrows indicate addition of agonist. Traces are representative of 3 experiments.
