Shows activity both for tyrosine-protein phosphate and serine-protein phosphate, but displays a strong preference toward phosphotyrosines (PubMed:10224087, PubMed:11863439). Specifically dephosphorylates and inactivates ERK1 and ERK2 (PubMed:10224087, PubMed:11863439). {ECO:0000269|PubMed:10224087, ECO:0000269|PubMed:11863439}. This is the function of DUSP3 (dual specificity phosphatase 3, ENSG00000108861).