The G2 checkpoint operates through a complex interplay of various proteins and signaling pathways. The key regulators include the [Cyclin-dependent kinases (CDKs)](), [Cyclins](), and tumor suppressor proteins such as [p53 and p21](). When DNA damage is detected, [ATM and ATR kinases]() are activated, which then phosphorylate and activate downstream effectors like [Chk1 and Chk2 kinases](). These effectors inhibit the activity of CDK1-Cyclin B complex, preventing the cell from entering mitosis.
