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Unlike the proposed role of Cbl as a negative regulator, our results suggest that the Cbl homologue Cbl -b has a positive role in T-cell signaling , most likely via a direct interaction with the upstream kinase Zap-70 .
 Cbl -b, upstream kinase, Cbl, Zap-70, Cbl, Cbl
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:
 Cbl -b, upstream kinase, Cbl, Zap-70, Cbl, Cbl