positive regulation of G2/MI transition of meiotic cell cycle

Definition

Target type: biologicalprocess

Any signaling pathway that activates or increases the activity of a cell cycle cyclin-dependent protein kinase to modulate the switch from G2 phase to MI phase of the meiotic cell cycle. [GOC:vw, PMID:25492408]

The G2/M transition, a critical checkpoint in the meiotic cell cycle, marks the transition from the second gap phase (G2) to the mitotic phase (M). This process involves a complex interplay of regulatory mechanisms that ensure the faithful duplication of chromosomes and the proper segregation of sister chromatids.

Positive regulation of the G2/M transition involves the activation of key molecular players, notably cyclin-dependent kinases (CDKs) and their regulatory subunits, cyclins. In particular, the CDK1/cyclin B complex, also known as maturation promoting factor (MPF), plays a pivotal role in driving the G2/M transition.

The accumulation of cyclin B during G2 phase is crucial for the activation of MPF. Once sufficient cyclin B levels are reached, the CDK1/cyclin B complex becomes active and phosphorylates a plethora of target proteins involved in chromatin condensation, nuclear envelope breakdown, and microtubule organization.

The activation of MPF is further regulated by the inhibitory phosphorylation of CDK1 by Wee1 and Myt1 kinases. These kinases ensure that the G2/M transition occurs only when the cell is fully prepared for mitosis. Counteracting the inhibitory phosphorylation, Cdc25 phosphatases remove inhibitory phosphates from CDK1, leading to its activation.

The G2/M transition is also influenced by various signaling pathways that respond to environmental cues and cell cycle status. For example, the DNA damage response pathway can halt the cell cycle progression at G2 by inhibiting the activation of MPF, preventing the entry into mitosis until DNA damage is repaired. Similarly, the spindle assembly checkpoint ensures that all chromosomes are properly attached to the spindle microtubules before the cell proceeds to anaphase and ultimately completes the cell cycle.

Overall, the positive regulation of the G2/M transition in the meiotic cell cycle involves a precise balance of activating and inhibitory signals. These signals fine-tune the activation of MPF, ensuring that the cell enters mitosis only when all the necessary conditions are met, guaranteeing accurate chromosome segregation and the formation of healthy gametes.'
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Proteins (3)

Compounds (33)