Tyrosine protein phosphatase which functions as a dosage-dependent inducer of mitotic progression. Directly dephosphorylates CDK1 and stimulates its kinase activity. Also dephosphorylates CDK2 in complex with cyclin E, in vitro (By similarity). Phosphorylation by PIM1 leads to an increase in phosphatase activity (By similarity). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Stimulated by B-type cyclins. Stimulated by PIM1-mediated phosphorylation (By similarity). Interacts with CCNB1/cyclin B1. Interacts with YWHAE/14-3-3 epsilon when phosphorylated. Interacts with CUL1 specifically when CUL1 is neddylated and active. Interacts with BTRC/BTRCP1 and FBXW11/BTRCP2. Interactions with CUL1, BTRC and FBXW11 are enhanced upon DNA damage. Interacts with PIM1. Interacts with CHEK2; mediates CDC25A phosphorylation and degradation in response to infrared-induced DNA damages (By similarity). Interacts with HSP90AB1; prevents heat shock-mediated CDC25A degradation and contributes to cell cycle progression (By similarity). Ubiquitously expressed in most developing tissue. High levels in the testis and lower levels in the ovary, particularly in germ cells. Lower levels also in kidney, liver, heart and muscle. First detected at the blastocyst stage. The phosphodegron motif mediates interaction with specific F-box proteins when phosphorylated. Putative phosphorylation sites at Ser-78 and Ser-81 appear to be essential for this interaction (By similarity). Phosphorylated by CHEK1 on Ser-75, Ser-123, Ser-172, Ser-271, Ser-284 and Thr-497 during checkpoint mediated cell cycle arrest. Also phosphorylated by CHEK2 on Ser-123, Ser-271, and Ser-284 during checkpoint mediated cell cycle arrest. Phosphorylation on Ser-172 and Thr-497 creates binding sites for YWHAE/14-3-3 epsilon which inhibits CDC25A. Phosphorylation on Ser-75, Ser-123, Ser-172, Ser-271 and Ser-284 may also promote ubiquitin-dependent proteolysis of CDC25A by the SCF complex. Phosphorylation of CDC25A at Ser-75 by CHEK1 primes it for subsequent phosphorylation at Ser-75, Ser-81 and Ser-87 by NEK11. Phosphorylation by NEK11 is required for BTRC-mediated polyubiquitination and degradation. Phosphorylation by PIM1 leads to an increase in phosphatase activity. Phosphorylated by PLK3 following DNA damage, leading to promote its ubiquitination and degradation (By similarity). Ubiquitinated by the anaphase promoting complex/cyclosome (APC/C) ubiquitin ligase complex that contains FZR1/CDH1 during G1 phase leading to its degradation by the proteasome. Ubiquitinated by a SCF complex containing BTRC and FBXW11 during S phase leading to its degradation by the proteasome. Deubiquitination by USP17L2/DUB3 leads to its stabilization (By similarity). Belongs to the MPI phosphatase family.