2892
We thus conclude that PTPases play a crucial role in the negative regulation of signal transduction culminating in T-lymphocyte activation .
 ( cell type: T-lymphocyte, None) , ( protein: PTPases, 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:
 ( cell type: T-lymphocyte, None) , ( protein: PTPases, None) 