collagen catabolic process

Definition

Target type: biologicalprocess

The proteolytic chemical reactions and pathways resulting in the breakdown of collagen in the extracellular matrix, usually carried out by proteases secreted by nearby cells. [GOC:mah, ISBN:0815316194]

Collagen catabolism is a complex process that involves the breakdown of collagen, a fibrous protein that provides structural support to various tissues in the body. It is tightly regulated and essential for normal tissue remodeling, wound healing, and the removal of damaged or senescent collagen. This process involves several key steps:

1. **Initiation:** Collagen catabolism is often triggered by various factors, including:

- **Enzymatic activation:** Specific enzymes, such as matrix metalloproteinases (MMPs) and cathepsins, can initiate collagen breakdown by cleaving specific peptide bonds within the collagen molecule.
- **Mechanical stress:** Physical forces can disrupt collagen fibers, exposing them to enzymatic degradation.
- **Oxidative stress:** Reactive oxygen species (ROS) can damage collagen, leading to its degradation.

2. **Cleavage and Fragmentation:** Once collagen is targeted, enzymes like MMPs and cathepsins act on specific sites within the collagen molecule, breaking it down into smaller fragments. These enzymes are highly specific and cleave collagen at different locations, generating distinct fragments with unique characteristics.

3. **Further Degradation:** Smaller collagen fragments can be further degraded by other enzymes, including lysosomal enzymes and peptidases, resulting in the production of individual amino acids.

4. **Removal and Recycling:** The breakdown products of collagen, including amino acids, can be removed from the extracellular matrix and used for various purposes, such as:

- **Cellular uptake:** Amino acids can be taken up by cells and used for protein synthesis or other metabolic processes.
- **Excretion:** Excess amino acids can be excreted from the body.

**Regulation:** Collagen catabolism is precisely regulated to maintain tissue homeostasis and prevent excessive degradation. The activity of collagen-degrading enzymes is regulated by a complex interplay of factors, including:

- **Hormones:** Various hormones, such as growth factors and cytokines, can influence collagen catabolism by modulating the expression and activity of collagen-degrading enzymes.
- **Extracellular matrix components:** Interactions between collagen and other extracellular matrix molecules can regulate the accessibility of collagen to degrading enzymes.
- **Cellular signaling pathways:** Intracellular signaling pathways can regulate the expression and activity of collagen-degrading enzymes in response to various stimuli.

**Clinical Relevance:** Dysregulation of collagen catabolism can contribute to various pathologies, including:

- **Osteoporosis:** Excessive bone collagen degradation can lead to weakened bones and an increased risk of fractures.
- **Arthritis:** Collagen breakdown in the joints can contribute to inflammation and joint damage.
- **Wound healing defects:** Impaired collagen catabolism can delay wound healing and lead to scar formation.
- **Cancer:** Some cancer cells can promote collagen catabolism to facilitate tumor growth and invasion.

**Overall, collagen catabolism is a crucial process that ensures the proper turnover and maintenance of collagen in various tissues. Its regulation is essential for tissue integrity, wound healing, and overall health. Aberrant collagen catabolism can contribute to a range of diseases, emphasizing the importance of understanding and targeting this process for therapeutic purposes.**'
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Proteins (46)

Compounds (302)