Dual specificity protein phosphatase (PubMed:9788880). Shows high activity towards MAPK1/ERK2 (PubMed:9788880). Also has lower activity towards MAPK14 and MAPK8 (PubMed:9788880). In arrested oocytes, plays a role in meiotic resumption (By similarity). Promotes nuclear envelope breakdown and activation of the CDK1/Cyclin-B complex in oocytes, probably by dephosphorylating and inactivating the conventional protein kinase C (cPKC) isozyme PRKCB (By similarity). May also inactivate PRKCA and/or PRKCG (By similarity). Also important in oocytes for normal chromosome alignment on the metaphase plate and progression to anaphase, where it might regulate activity of the spindle-assembly checkpoint (SAC) complex (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 Strongly inhibited by sodium orthovanadate. Interacts with MAPK1/ERK2; the interaction enhances DUSP7 phosphatase activity. Strongly expressed in liver (PubMed:8670865). Expressed at significantly higher levels in malignant hematopoietic cells than in corresponding non-malignant cells (PubMed:14576828). Belongs to the protein-tyrosine phosphatase family. Non-receptor class dual specificity subfamily. An out-of-frame translation product, PYST2SB, has been experimentally demonstrated to be formed from the alternative promoter. The expression of the in-frame product has not yet been shown.