Cdc25 is a family of serine/threonine phosphatases that dephosphorylate and activate cyclin-dependent kinases (CDKs), thereby regulating cell cycle progression. The Cdc25 family includes Cdc25A, Cdc25B, and Cdc25C, which play key roles in the G1/S and G2/M phase transitions. Cdc25 removes inhibitory phosphate groups from CDK complexes, promoting cell entry into mitosis. Its activity is tightly regulated by DNA damage checkpoints to prevent cells with damaged DNA from progressing to the next phase.