Analysis of the defective signal transduction mechanism through the platelet thromboxane A2 receptor in a patient with polycythemia vera

We previously reported a patient wiht polycythemia vera whose platelets showed subnormal responses to thromboxane A 2 (TXA 2 ) (Thromb Haemostas 1987; 57: 158-64). The patient's platelets showed normal binding activity to TXA 2 analogues but the generation of second messengers was defective. We further studied the mechanism of this dysfunction in this work. The coupling of TXA 2 receptor with its relevant GTP binding protein was examined using STA 2 (a synthetic TXA 2 mimetic)-induced augmentation of GTPase activity as its measure