positive regulation of cell cycle

Definition

Target type: biologicalprocess

Any process that activates or increases the rate or extent of progression through the cell cycle. [GOC:go_curators]

Positive regulation of the cell cycle is a fundamental biological process that ensures the orderly progression of cell division. It involves a complex interplay of regulatory proteins, signaling pathways, and checkpoints that control the transition between different phases of the cell cycle, ensuring that DNA replication and chromosome segregation occur accurately.

Key components of this process include:

1. **Cyclins and cyclin-dependent kinases (CDKs):** These proteins form complexes that drive the transition between cell cycle phases. Cyclins are regulatory proteins whose levels fluctuate throughout the cycle, while CDKs are enzymes that phosphorylate target proteins, triggering downstream events.
2. **Cell cycle checkpoints:** These checkpoints monitor the integrity of the cell cycle, halting progression if errors are detected. Major checkpoints include the G1/S checkpoint, which monitors DNA integrity, and the G2/M checkpoint, which ensures that DNA replication is complete.
3. **Signal transduction pathways:** External signals, such as growth factors and nutrients, can activate signaling pathways that influence cell cycle progression. These pathways can either promote or inhibit cell cycle entry and progression.

**Detailed steps:**

1. **G1 phase:** This is the first gap phase, during which the cell grows and prepares for DNA replication. Key events include the accumulation of cyclins and CDKs, which activate transcription factors that promote the synthesis of proteins necessary for DNA replication.
2. **S phase:** This phase is characterized by DNA replication. Cyclin E-CDK2 complexes activate DNA replication machinery, ensuring that each chromosome is replicated only once.
3. **G2 phase:** This is the second gap phase, during which the cell continues to grow and prepares for mitosis. Cyclin B-CDK1 complexes accumulate, initiating the entry into mitosis.
4. **M phase:** This phase involves nuclear division (mitosis) and cytoplasmic division (cytokinesis). Cyclin B-CDK1 complexes trigger chromosome condensation, spindle formation, and the separation of sister chromatids.

**Positive regulation:**

Positive regulation of the cell cycle involves mechanisms that promote cell cycle progression. This includes:

1. **Activation of cyclins and CDKs:** The accumulation of cyclins and the activation of CDKs are key drivers of cell cycle progression.
2. **Activation of signaling pathways:** Growth factors and other external signals can activate signaling pathways that promote cell cycle entry and progression.
3. **Overcoming checkpoints:** Certain signals or conditions can override checkpoints, allowing the cell cycle to proceed even in the presence of errors.

**Overall, positive regulation of the cell cycle is a tightly controlled process that ensures accurate DNA replication, chromosome segregation, and the production of new cells. Dysregulation of this process can contribute to diseases such as cancer. '
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Proteins (13)

Compounds (567)