8923
IFN-alpha enhanced tyrosine phosphorylation of STAT1, STAT3 , STAT4 , STAT5a , and STAT5b .
 ( protein: STAT4, None) , ( protein: STAT3, None) , ( protein: IFN-alpha, None) , ( protein: STAT5a, None) , ( protein: STAT5b, 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: STAT4, None) , ( protein: STAT3, None) , ( protein: IFN-alpha, None) , ( protein: STAT5a, None) , ( protein: STAT5b, None) 