5336
The IL-2 enhancer contains a functional motif named CD28 response element ( CD28RE ) that serves a role as a target for mitogenic T cell activation signals .
 ( protein: CD28, None) , ( protein: IL-2, None) , ( DNA: CD28 response element, None) , ( DNA: CD28RE, 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: CD28, None) , ( protein: IL-2, None) , ( DNA: CD28 response element, None) , ( DNA: CD28RE, None) 