Macroscopic differences in HMGA oncoproteins post-translational modifications:C-terminal phosphorylation of HMGA2 affects its DNA binding properties.

We have performed an LC/MS screening on several different cell lines to investigate HMGA proteins expression and their posttranslational modifications in order to detect distinctive modification patterns for each. Our analyses evidenced relevant macroscopic differences in the phosphorylation and methylation patterns of these proteins. These differences occur both within the HMGA family members and in the different cell types. Focusing on HMGA2, we have mapped its in vivo phosphorylation sites demonstrating that, similarly to the HMGA1 proteins, it is highly phosphorylated on the acidic C-terminal tail and that these modifications affect its DNA binding properties.