positive regulation of anaphase-promoting complex-dependent catabolic process

Definition

Target type: biologicalprocess

Any process that activates or increases the frequency, rate or extent of anaphase-promoting complex-dependent catabolic process. [GO_REF:0000058, GOC:TermGenie, PMID:10921876]

Positive regulation of anaphase-promoting complex-dependent catabolic process is a crucial step in cell division, specifically during the transition from metaphase to anaphase. This process involves the activation of the anaphase-promoting complex (APC), also known as the cyclosome, a ubiquitin ligase that triggers the degradation of key regulatory proteins required for proper chromosome segregation. Here's a breakdown of the process:

1. **Activation of the APC:** The APC exists in an inactive state until it is activated by the binding of a specific activating subunit, either CDC20 or CDH1. CDC20 is primarily involved in the metaphase-to-anaphase transition, while CDH1 is crucial for the exit from mitosis and entry into G1. The activation of APC is triggered by various factors, including the activation of the mitotic checkpoint complex (MCC), which ensures that all chromosomes are correctly aligned at the metaphase plate.

2. **Ubiquitination of Target Proteins:** Once activated, the APC complex utilizes its ubiquitin ligase activity to attach ubiquitin chains to specific target proteins. Ubiquitination serves as a signal for the proteasome, a protein degradation machinery, to degrade the tagged proteins.

3. **Targeted Degradation of Regulatory Proteins:** The APC targets a variety of proteins essential for regulating cell cycle progression. Some key targets include:

* **Securin:** A protein that holds sister chromatids together, preventing their premature separation. Degradation of securin allows the separation of sister chromatids, marking the onset of anaphase.
* **Cyclin B:** A regulatory protein that activates the cyclin-dependent kinase (CDK1), crucial for driving the cell through mitosis. Degradation of cyclin B deactivates CDK1, promoting the exit from mitosis.
* **Other mitotic regulators:** The APC targets other proteins involved in mitotic spindle assembly, chromosome condensation, and other aspects of cell division.

4. **Cell Cycle Progression:** The degradation of these target proteins by the APC triggers a cascade of events leading to the proper segregation of chromosomes and the completion of mitosis. This includes the separation of sister chromatids, the disassembly of the mitotic spindle, and the reassembly of the nuclear envelope around the newly separated chromosomes.

5. **Regulation and Feedback Loops:** The activation and activity of the APC are tightly regulated by multiple feedback loops. The degradation of securin and cyclin B itself contributes to the inactivation of the APC, preventing the premature degradation of other key proteins. Additionally, phosphorylation and other post-translational modifications can fine-tune the activity and specificity of the APC complex.

In summary, positive regulation of APC-dependent catabolic process involves a sophisticated interplay of proteins and enzymes that ensures the precise degradation of key regulatory proteins, facilitating a smooth transition from metaphase to anaphase and ultimately ensuring proper chromosome segregation during cell division.'"

Proteins (1)

Compounds (1)