4626
COS-1 cells , co-expressing the human IL-10R and individual STAT proteins , confirmed a preference of the IL-10R for STAT3 and STAT1 .
 ( protein: STAT3, None) , ( cell line: COS-1 cells, None) , ( protein: IL-10R, None) , ( protein: STAT proteins, None) , ( protein: STAT1, None) , ( protein: IL-10R, 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: STAT3, None) , ( cell line: COS-1 cells, None) , ( protein: IL-10R, None) , ( protein: STAT proteins, None) , ( protein: STAT1, None) , ( protein: IL-10R, None) 