11885
In contrast, prostaglandin I2 ( PGI2 ), a strong negative regulator of platelet function , inhibited agonist-induced as well as Ca2+ -induced activation of Rap1 .
 ( protein: Rap1, None) , ( cell type: platelet, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: Rap1, None) , ( cell type: platelet, None) 