6146
The former pathway is recruited by all ERK -activating stimuli , whereas the latter pathway uses an undefined serine kinase and is recruited selectively by cytokines .
 ( protein: cytokines, None) , ( protein: ERK, None) , ( protein: serine kinase, 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: cytokines, None) , ( protein: ERK, None) , ( protein: serine kinase, None) 