low-density lipoprotein particle receptor catabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the breakdown of a low-density lipoprotein particle receptor molecule, a macromolecule that undergoes combination with a hormone, neurotransmitter, drug or intracellular messenger to initiate a change in cell function. [GOC:mah]

The catabolism of low-density lipoprotein (LDL) particles, also known as the LDL receptor pathway, is a crucial process for maintaining cholesterol homeostasis in the body. It involves a series of steps:

1. **Binding:** LDL particles, carrying cholesterol, bind to the LDL receptor on the surface of cells, particularly in the liver. The LDL receptor is a transmembrane protein with a structure that allows for specific binding of LDL.

2. **Endocytosis:** Once bound, the LDL receptor-LDL complex is internalized into the cell through endocytosis, a process where a portion of the cell membrane invaginates to form a vesicle containing the complex.

3. **Vesicle Transport and Fusion:** The vesicle containing LDL and the receptor travels through the cellular machinery, ultimately merging with a lysosome, an organelle containing digestive enzymes.

4. **LDL Degradation:** Within the lysosome, enzymes break down the LDL particle, releasing cholesterol and other components. The LDL receptor, being a protein, is also degraded.

5. **Cholesterol Utilization:** The released cholesterol can then be used by the cell for various purposes, including the synthesis of new membranes, steroid hormones, and bile acids.

6. **Receptor Recycling:** A portion of the LDL receptor is recycled back to the cell surface, allowing for continuous uptake of LDL particles.

This process is tightly regulated, ensuring that cholesterol levels remain within a healthy range. If the LDL receptor pathway is disrupted, it can lead to elevated LDL levels in the blood, increasing the risk of cardiovascular disease. For instance, mutations in the LDL receptor gene can cause familial hypercholesterolemia, a genetic disorder characterized by extremely high cholesterol levels. Conversely, certain medications can increase LDL receptor activity, lowering LDL levels and reducing the risk of heart disease.'
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Proteins (1)

Compounds (2)