6146
The former pathway is recruited by all ERK -activating stimuli , whereas the latter pathway uses an undefined serine kinase and is recruited selectively by cytokines .
 protein: cytokines; protein: ERK; protein: serine kinase
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: cytokines, ERK, serine kinase 
Answer:
 protein: cytokines; protein: ERK; protein: serine kinase