G2/m checkpoint

Definition

The g2/m checkpoint is a critical regulatory point in the cell cycle that ensures a cell is fully prepared to enter mitosis. This checkpoint assesses DNA integrity and the completeness of DNA replication, preventing cells with damaged or incomplete DNA from progressing to division. By maintaining genomic stability, the g2/m checkpoint plays a vital role in the overall control of the cell cycle and helps prevent errors during cell division.

5 Must Know Facts For Your Next Test

1. The g2/m checkpoint is crucial for ensuring that any DNA damage is repaired before the cell enters mitosis.
2. Proteins such as p53 play important roles in sensing DNA damage at the g2/m checkpoint and initiating repair processes or apoptosis if necessary.
3. Failure to properly regulate the g2/m checkpoint can lead to uncontrolled cell division, which is a hallmark of cancer.
4. This checkpoint is also involved in the decision-making process for whether a cell should proceed to mitosis or delay division until conditions are favorable.
5. The activation of cyclin-dependent kinases (CDKs) at this checkpoint is essential for the transition from g2 phase to mitosis.

Review Questions

• How does the g2/m checkpoint contribute to maintaining genomic stability during the cell cycle?
  • The g2/m checkpoint plays a key role in maintaining genomic stability by checking for any DNA damage or incomplete replication before a cell enters mitosis. If damage is detected, proteins like p53 can trigger repair mechanisms or initiate apoptosis, thereby preventing damaged DNA from being passed on to daughter cells. This ensures that only healthy, fully prepared cells proceed to division, reducing the risk of mutations and other errors during mitosis.
• Discuss the molecular mechanisms involved in regulating the g2/m checkpoint and their implications for cancer biology.
  • The g2/m checkpoint is regulated by several proteins, including cyclin-dependent kinases (CDKs) and their cyclin partners. When conditions are right, these proteins promote progression through the checkpoint. However, if DNA damage is present, checkpoints such as p53 can halt progression by inhibiting CDK activity. Disruption in these regulatory mechanisms can lead to unchecked cell division, contributing to tumorigenesis and making understanding these pathways essential in cancer biology.
• Evaluate the importance of the g2/m checkpoint in drug development aimed at targeting cancer cells.
  • In drug development, targeting the g2/m checkpoint has become an important strategy for treating cancer. Many cancer therapies aim to exploit the vulnerabilities of tumor cells that have defective checkpoint controls. By using drugs that further disrupt this checkpoint, it may be possible to induce apoptosis in cancer cells that are already compromised in their ability to repair DNA damage. Evaluating how specific inhibitors affect g2/m regulation can lead to more effective treatments that specifically target cancerous cells while sparing normal cells, highlighting its significance in contemporary cancer therapies.

Related terms

Cell Cycle: The series of phases that a cell goes through leading to its division and replication, including interphase and mitotic phase.

Checkpoints: Regulatory pathways in the cell cycle that monitor and ensure the proper progression of cells through different phases.

Mitosis: The process of cell division where a single cell divides to produce two genetically identical daughter cells.