4711
Active Raf-1 phosphorylates and activates the mitogen-activated protein (MAP) kinase /extracellular signal-regulated kinase kinase 1 ( MEK1 ), which in turn phosphorylates and activates the MAP kinases/extracellular signal regulated kinases , ERK1 and ERK2 .
 ( protein: Raf-1, None) , ( protein: ERK1, None) , ( protein: ERK2, None) , ( protein: mitogen-activated protein (MAP) kinase, None) , ( protein: mitogen-activated protein (MAP) kinase /extracellular signal-regulated kinase kinase 1, None) , ( protein: MEK1, None) , ( protein: MAP kinases/extracellular signal regulated kinases, 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: Raf-1, None) , ( protein: ERK1, None) , ( protein: ERK2, None) , ( protein: mitogen-activated protein (MAP) kinase, None) , ( protein: mitogen-activated protein (MAP) kinase /extracellular signal-regulated kinase kinase 1, None) , ( protein: MEK1, None) , ( protein: MAP kinases/extracellular signal regulated kinases, None) 