11939
Both MAP ERK kinase kinase-1 ( MEKK1 ) and Raf are activated strongly by FMLP , but minimally by PAF .
 PAF, MEKK1, FMLP, MAP ERK kinase kinase-1, Raf
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:
 PAF, MEKK1, FMLP, MAP ERK kinase kinase-1, Raf