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p21ras is activated by the T cell antigen receptor ( TCR ) and then co-ordinates important signaling pathways for T lymphocyte activation .
 TCR, T cell antigen receptor, T lymphocyte, p21ras
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 TCR, T cell antigen receptor, T lymphocyte, p21ras