6100
Studies with motheaten mice , which lack the SHP1 protein tyrosine phosphatase , indicate that this enzyme plays an important negative role in T cell antigen receptor ( TCR ) signaling .
 ( protein: SHP1, None) , ( protein: tyrosine phosphatase, None) , ( protein: T cell antigen receptor, None) , ( protein: SHP1 protein, None) , ( protein: TCR, 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: SHP1, None) , ( protein: tyrosine phosphatase, None) , ( protein: T cell antigen receptor, None) , ( protein: SHP1 protein, None) , ( protein: TCR, None) 