CDC25B

CDC25B (Cell Division Cycle 25B) is a human gene encoding a protein belonging to the CDC25 family of dual-specificity phosphatases. These phosphatases play a crucial role in regulating cell cycle progression, primarily by dephosphorylating and activating cyclin-dependent kinases (CDKs).

Specifically, CDC25B activates CDKs involved in the G2/M transition, the checkpoint between the G2 phase (the period of cell growth after DNA replication) and the M phase (mitosis). The protein removes inhibitory phosphate groups from specific tyrosine and threonine residues on CDKs, allowing them to complex with cyclins and drive the cell cycle forward.

CDC25B is typically located in the cytoplasm, but upon activation, it translocates to the nucleus where it activates nuclear CDKs. The activation of CDC25B itself is a complex process, involving phosphorylation by other kinases and regulated by checkpoints that monitor DNA integrity and replication completion. Damage to DNA or incomplete replication can trigger pathways that inhibit CDC25B activity, preventing premature entry into mitosis and allowing time for repair.

The gene encoding CDC25B is located on chromosome 20q13.12. Aberrant expression or activity of CDC25B has been implicated in various cancers. Overexpression of CDC25B can lead to uncontrolled cell proliferation and tumor development, while its inhibition may have anti-cancer therapeutic potential. Different isoforms of CDC25B exist, arising from alternative splicing, which can exhibit distinct functions and regulation. Understanding the specific roles of CDC25B isoforms in different cellular contexts is an area of ongoing research.