4228
The data further indicate that the IL-7R alpha chains are directly involved in the activation of JAKs and STATs and have a major role in proliferative signaling in precursor B cells .
 ( protein: JAKs, None) , ( protein: STATs, None) , ( protein: IL-7R alpha chains, None) , ( cell type: precursor B cells, 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: JAKs, None) , ( protein: STATs, None) , ( protein: IL-7R alpha chains, None) , ( cell type: precursor B cells, None) 