negative regulation of cell division

Definition

Target type: biologicalprocess

Any process that stops, prevents, or reduces the frequency, rate or extent of cell division. [GOC:ai]

Negative regulation of cell division is a crucial biological process that ensures proper growth and development by controlling the rate and timing of cell proliferation. It involves a complex interplay of regulatory mechanisms that act to suppress or inhibit cell division when necessary. Here's a detailed description of the key components and processes involved:

**1. Cell Cycle Checkpoints:**

* **G1 Checkpoint:** This checkpoint ensures that the cell has adequate nutrients, growth factors, and DNA integrity before committing to replication. Key players include:
* **p53:** A tumor suppressor gene that halts cell cycle progression in response to DNA damage.
* **Rb:** A retinoblastoma protein that prevents the transcription of genes necessary for DNA replication.
* **G2 Checkpoint:** This checkpoint verifies that DNA replication has been completed accurately and that the cell has enough resources for mitosis. Key players include:
* **p34cdc2:** A cyclin-dependent kinase that activates the G2-to-M transition.
* **Wee1:** A kinase that inhibits p34cdc2 activity until DNA replication is complete.
* **Spindle Assembly Checkpoint:** This checkpoint ensures that chromosomes are properly attached to the spindle fibers before proceeding to anaphase (chromosome separation). Key players include:
* **Mad2:** A protein that monitors chromosome attachment and signals to stop mitosis if errors are detected.

**2. Signaling Pathways:**

* **TGF-β Pathway:** Transforming growth factor beta (TGF-β) signaling can inhibit cell division by promoting cell cycle arrest in the G1 phase.
* **Hippo Pathway:** This pathway regulates organ size and cell proliferation by controlling cell growth and apoptosis.
* **Wnt Pathway:** In some contexts, the Wnt pathway can inhibit cell division by promoting cell cycle arrest or differentiation.

**3. Protein Kinases and Phosphatases:**

* **Cyclin-dependent Kinases (CDKs):** These kinases are activated by cyclins and drive the cell cycle through different phases. However, their activity can be inhibited by specific CDK inhibitors.
* **Phosphatases:** These enzymes can dephosphorylate and inactivate proteins involved in promoting cell division.

**4. Transcription Factors:**

* **p53:** As mentioned earlier, p53 is a transcription factor that can activate genes that arrest the cell cycle or induce apoptosis.
* **Rb:** Rb inhibits the transcription of genes required for cell cycle progression.

**5. MicroRNAs:**

* **MicroRNAs (miRNAs):** These small non-coding RNAs can regulate gene expression by targeting mRNAs for degradation or translational repression. Some miRNAs play a role in inhibiting cell division.

**Consequences of Dysregulation:**

Failure to properly regulate cell division can lead to a variety of problems, including:

* **Uncontrolled Cell Growth and Cancer:** When negative regulation fails, cells may divide unchecked, leading to tumor formation and cancer development.
* **Developmental Defects:** Aberrant cell division during embryonic development can result in birth defects and malformations.
* **Tissue Homeostasis Imbalances:** Excessive or insufficient cell division can disrupt tissue homeostasis, leading to various disorders.

**Conclusion:**

Negative regulation of cell division is a complex and multifaceted process involving a delicate balance of various regulatory mechanisms. These mechanisms ensure that cell division occurs in a controlled manner, contributing to proper growth, development, and tissue homeostasis. Dysregulation of these processes can have significant consequences, highlighting the importance of maintaining this delicate equilibrium.'
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Proteins (5)

Compounds (14)