Chaperone-mediated autophagy.
Level 5 - mechanism / opinion, no new human data
Narrative review of cellular and molecular mechanisms without human clinical data
PubMed 17404494 · doi:10.4161/auto.4144
What was done
This narrative review summarizes molecular mechanisms controlling chaperone-mediated autophagy (CMA). It describes the roles of cytosolic and luminal chaperones, the regulation and membrane dynamics of the receptor LAMP-2A, cellular responses to nutrient deprivation and oxidative stress, and the mechanistic basis for CMA decline in aging.
What was found
CMA is responsible for degrading 30% of cytosolic proteins during prolonged nutrient deprivation. Translocation of unfolded substrate proteins across the lysosomal membrane depends on LAMP-2A and luminal chaperones. Oxidative stress activates CMA via transcriptional upregulation of LAMP-2A, while inhibitors of glucose-6-phosphate dehydrogenase and Hsp90 reduce CMA. RNAi knockdown of LAMP-2A reduces CMA, increases cellular vulnerability to oxidative stress, and triggers compensatory macroautophagy. Age-related reduction in CMA is mediated by decreased LAMP-2A in the lysosomal membrane due to increased degradation and reduced reinsertion capacity. No other quantitative figures were reported in the abstract.
Why it matters
This review outlines the molecular framework of selective lysosomal protein degradation and explains how age-dependent loss of LAMP-2A impairs cellular stress resistance.
Limits
The abstract describes a narrative review of mechanistic bench research without systematic search criteria, human trial data, or sample sizes.
Cited by
- supports Fasting beyond 3 days triggers chaperone-mediated autophagy (CMA) to degrade misfolded and damaged proteins.