May play a role in the ERK signaling pathway by inhibiting the dephosphorylation of ERK by phosphatase PP2A-PPP2R5C holoenzyme. Also acts as an ERK downstream effector mediating survival. As a member of the NUPR1/RELB/IER3 survival pathway, may provide pancreatic ductal adenocarcinoma with remarkable resistance to cell stress, such as starvation or gemcitabine treatment. {ECO:0000269|PubMed:12356731, ECO:0000269|PubMed:16456541, ECO:0000269|PubMed:22565310}. This is the function of IER3 (immediate early response 3, ENSG00000137331).