CDC25B, Active

CDC25B (also known as cell division cycle 25 homolog B) is a member of the CDC25 family of phosphatases that activate the cyclin dependent kinase CDC2 by removing two phosphate groups. CDC25B is required for cell entry into mitosis. CDC25B shuttles between the nucleus and the cytoplasm due to nuclear localization and nuclear export signals. Cdc25B is the first genetic model for studying the mechanisms regulating prophase arrest in vertebrates (1). The regulation of CDC25B phosphorylation by p38 is a critical event for initiating the G2/M checkpoint after ultraviolet radiation (2).