8144
Furthermore, CoCl2 also caused time-dependent tyrosine phosphorylation of mitogen-activated protein (MAP) kinase isoform ERK2 without significantly affecting ERK1 , indicating ERK2 is the preferred substrate for upstream kinase of the MAPK pathway .
 ( protein: ERK2, None) , ( protein: ERK2, None) , ( protein: upstream kinase, None) , ( protein: ERK1, None) , ( protein: MAPK, None) , ( protein: mitogen-activated protein (MAP) 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: ERK2, None) , ( protein: ERK2, None) , ( protein: upstream kinase, None) , ( protein: ERK1, None) , ( protein: MAPK, None) , ( protein: mitogen-activated protein (MAP) kinase, None) 