What effect does the phosphorylation of Cdc25 by M-Cdk have?

The phosphorylation of Cdc25 by M-Cdk leads to its activation, which then promotes the activation of more M-Cdk. This process is a crucial part of the positive feedback loop in the cell cycle machinery. When M-Cdk is active, it phosphorylates Cdc25, enhancing its activity. Cdc25 is a phosphatase that removes inhibitory phosphates from cyclin-dependent kinase (Cdk), specifically M-Cdk in this case, allowing it to become fully activated.

Once Cdc25 is activated and promotes the activation of more M-Cdk, this amplifies the cell's progression through mitosis. The increase of active M-Cdk then facilitates further cell cycle events associated with mitosis, pushing the cell closer to completing cell division. This cascading effect is critical for ensuring that the transition through the M phase is swift and effective, showcasing a well-regulated mechanism within cell cycle progression.