3821
However, the combined treatment with PDTC and PMA , two agents that synergize on AP-1 activation , resulted in the persistent phosphorylation of ERK-2 .
 protein: ERK-2; protein: AP-1
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: ERK-2, AP-1 
Answer:
 protein: ERK-2; protein: AP-1