regulation of exit from mitosis

Definition

Target type: biologicalprocess

Any process involved in the progression from anaphase/telophase to G1 that is associated with a conversion from high to low mitotic CDK activity. [GOC:rn]

Regulation of exit from mitosis is a tightly controlled process that ensures proper chromosome segregation and cell division. It involves a complex interplay of signaling pathways, protein modifications, and changes in gene expression.

**Key events in exit from mitosis:**

1. **Cyclin B degradation:** Cyclin B, a key regulator of mitotic entry, is degraded by the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase. This triggers the inactivation of cyclin-dependent kinases (CDKs), which are essential for mitotic progression.
2. **Dephosphorylation of mitotic substrates:** CDK inactivation leads to the dephosphorylation of various proteins that were phosphorylated during mitosis, including proteins involved in chromosome condensation, nuclear envelope breakdown, and microtubule dynamics.
3. **Nuclear envelope reassembly:** Dephosphorylation of nuclear lamins and other nuclear envelope proteins allows for the reassembly of the nuclear envelope around the segregated chromosomes.
4. **Chromosome decondensation:** The dephosphorylation of histone proteins results in chromosome decondensation, returning the chromosomes to their interphase state.
5. **Microtubule depolymerization:** Microtubule-associated proteins are dephosphorylated, contributing to the depolymerization of the mitotic spindle.
6. **Cytokinesis:** The cleavage furrow forms, dividing the cytoplasm and completing cell division.

**Signaling pathways involved in mitotic exit:**

* **The spindle assembly checkpoint (SAC):** This pathway ensures that all chromosomes are properly attached to the mitotic spindle before anaphase onset.
* **The Polo kinase pathway:** Polo kinase is a serine/threonine kinase that plays a crucial role in mitotic progression and exit.
* **The Wee1/Cdc25 pathway:** This pathway regulates CDK activity through phosphorylation and dephosphorylation events.

**Regulation of mitotic exit:**

* **Phosphorylation/dephosphorylation events:** The activity of key proteins, including CDKs and their regulators, is tightly controlled by phosphorylation and dephosphorylation.
* **Ubiquitination and proteolysis:** Proteins involved in mitotic progression, such as cyclins and APC/C components, are targeted for degradation by ubiquitination.
* **Transcriptional regulation:** The expression of genes involved in mitotic exit is regulated through transcription factors and signaling pathways.

**Consequences of defects in mitotic exit:**

* **Chromosome missegregation:** Defective mitotic exit can lead to aneuploidy, which is the presence of an abnormal number of chromosomes in cells.
* **Cell cycle arrest:** Cells may be unable to exit mitosis properly, leading to cell cycle arrest and potentially apoptosis.
* **Cancer development:** Defects in mitotic exit can contribute to the development of cancer by promoting genomic instability and uncontrolled cell growth.

Regulation of exit from mitosis is a complex and critical process that ensures the faithful segregation of chromosomes and the completion of cell division. Dysregulation of this process can have serious consequences for cell function and organismal health.'
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Proteins (2)

Compounds (36)