1883
In particular , we demonstrate that upon stress - induced phosphorylation of p53 on Ser46 by homeodomain interacting protein kinase 2 , Pin1 stimulates its mitochondrial trafficking signal , that is , monoubiquitination .
 Chemical: Ser46
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Ser46