13412
We have previously shown that the presence of the CD4 cytoplasmic tail is critical for human immunodeficiency virus (HIV)-induced apoptosis (J.Corbeil, M.Tremblay, and D.D.Richman, J.Exp.Med.183:39-48, 1996).
 ( protein: CD4 cytoplasmic tail, 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: CD4 cytoplasmic tail, None) 