May play a role in cell cycle regulation. Dual specificity CC phosphatase active toward substrates containing either phosphotyrosine or phosphoserine residues (PubMed:8127873, PubMed:8242750). Dephosphorylates CDK2 at 'Thr-160' in a cyclin-dependent manner (PubMed:7569954). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate Interacts with cyclin-dependent kinases such as CDK1, CDK2 and CDK3. Does not interact with CDK4. Interacts (via C-terminus) with phosphorylated CDK2 (via C-terminal helix). Interacts with MS4A3 (via C-terminus); the interaction enhances CDKN3 enzymatic activity. Up-regulated in breast and prostate cancer cells. The gene represented in this entry may be involved in disease pathogenesis. Belongs to the protein-tyrosine phosphatase family.