pexophagie

Pexophagie, also known as pexophagy in English, is a selective form of autophagy in which peroxisomes are degraded by the lysosome. It serves as a quality-control and homeostatic process to regulate peroxisome number and function.

The process is initiated when peroxisomes are damaged or when metabolic conditions change, such as a shift in substrate availability. Selective autophagy receptors recognize peroxisomal components, link them to the core autophagy machinery, and facilitate enclosing the organelle within autophagosomes that subsequently fuse with lysosomes.

In yeast, receptor proteins on the peroxisome membrane recruit autophagy factors to promote pexophagy, exemplified by Atg30 and associated proteins that coordinate Atg8 and other components. In mammals, pexophagy can involve ubiquitination of peroxisomal proteins and autophagy receptors such as p62/SQSTM1 and NBR1 that bind LC3 to deliver peroxisomes to autophagosomes.

Pexophagy contributes to peroxisome homeostasis by removing damaged or superfluous peroxisomes and by allowing adaptation to metabolic and oxidative stress. Dysregulation or impairment of pexophagy has implications for metabolic disorders and is being studied in the contexts of aging and neurodegenerative disease. Ongoing research aims to clarify the signaling pathways and the relevance of pexophagy to human health.