Can dephosphorylate single and diphosphorylated synthetic MAPK peptides, with preference for the phosphotyrosine and diphosphorylated forms over phosphothreonine. In vitro, dephosphorylates p-nitrophenyl phosphate (pNPP). 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 Activated by manganese ions, inhibited by iodoaretic acid. Optimum pH is 6.0. Optimum temperature is 55 degrees Celsius. Translocates to cytoplasm in response to apoptotic stimuli such as staurosporine treatment. Widely expressed with highest levels in liver, brain, ovary and testis. Belongs to the protein-tyrosine phosphatase family. Non-receptor class dual specificity subfamily.