Inactivates MAP kinases. Has a specificity for the ERK family (PubMed:8626780). Implicated in muscle and neuronal differentiation (PubMed:8631996). Plays an important role in alleviating chronic postoperative pain. Necessary for the normal dephosphorylation of the long-lasting phosphorylated forms of spinal MAPK1/3 and MAP kinase p38 induced by peripheral surgery, which drives the resolution of acute postoperative allodynia (By similarity). Also important for dephosphorylation of MAPK1/3 in local wound tissue, which further contributes to resolution of acute pain (By similarity). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Interacts with MAPK1/ERK2. Expressed in lung, heart, brain, and kidney, but not significantly in skeletal muscle or testis. Belongs to the protein-tyrosine phosphatase family. Non-receptor class dual specificity subfamily.