G2/M Checkpoint

Definition

The G2/M checkpoint is a critical control point in the cell cycle that ensures the cell is ready to undergo mitosis. It acts as a gatekeeper, monitoring the cell's readiness to divide and preventing it from progressing to mitosis if the conditions are not favorable.

5 Must Know Facts For Your Next Test

1. The G2/M checkpoint ensures that the cell has completed DNA replication and repaired any DNA damage before allowing the cell to enter mitosis.
2. This checkpoint is regulated by a complex network of signaling pathways that monitor cellular conditions, such as DNA integrity and the availability of growth factors.
3. Cyclin-dependent kinases (CDKs) are key regulators of the G2/M checkpoint, controlling the activity of proteins involved in the initiation of mitosis.
4. Failure to properly arrest the cell cycle at the G2/M checkpoint can lead to genomic instability and the potential development of cancer.
5. The G2/M checkpoint is a critical safeguard that ensures the fidelity of cell division, preventing the propagation of cells with genetic abnormalities.

Review Questions

• Explain the role of the G2/M checkpoint in the cell cycle.
  • The G2/M checkpoint is a crucial control point in the cell cycle that ensures the cell is ready to undergo mitosis. It monitors the cell's readiness by checking for the completion of DNA replication and the presence of any DNA damage. If the conditions are not favorable, the checkpoint will arrest the cell cycle, preventing the cell from progressing to mitosis and dividing until the necessary requirements are met. This checkpoint is essential for maintaining genomic stability and preventing the propagation of cells with genetic abnormalities.
• Describe the regulatory mechanisms involved in the G2/M checkpoint.
  • The G2/M checkpoint is regulated by a complex network of signaling pathways that involve cyclin-dependent kinases (CDKs) and their associated regulatory proteins. CDKs play a central role in controlling the activity of proteins involved in the initiation of mitosis. When cellular conditions are not favorable, such as the presence of DNA damage, checkpoint signaling pathways are activated, leading to the inhibition of CDK activity and the arrest of the cell cycle at the G2/M transition. This allows the cell time to repair any DNA damage before proceeding to mitosis, ensuring the fidelity of cell division.
• Analyze the consequences of a failure in the G2/M checkpoint.
  • Failure to properly arrest the cell cycle at the G2/M checkpoint can have serious consequences for the cell and the organism as a whole. If a cell with unrepaired DNA damage or other abnormalities is allowed to progress to mitosis, it can lead to the propagation of cells with genomic instability. This genomic instability can contribute to the development of cancer, as it increases the likelihood of mutations and chromosomal abnormalities being passed on to daughter cells. Proper functioning of the G2/M checkpoint is therefore crucial for maintaining cellular integrity and preventing the development of cancerous cells.

Related terms

Cell Cycle: The series of events that a cell goes through, including growth, DNA replication, and cell division, to produce two daughter cells.

Mitosis:

The process of cell division that results in the formation of two genetically identical daughter cells.

Cyclin-Dependent Kinases (CDKs):

A family of enzymes that play a crucial role in regulating the progression of the cell cycle by phosphorylating specific target proteins.