13020
In this study, we present evidence indicating that signal transduction pathways induced by PGE2 necessitate the participation of cyclic AMP , protein kinase A , and Ca2+ .
 protein: protein kinase A
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: protein kinase A 
Answer:
 protein: protein kinase A