Loss of proteostasis

Proteostasis is the totality of processes by which a cell keeps its proteins in working order. It covers three jobs: newly formed protein chains must fold correctly into their three-dimensional shape, misfolded copies should be corrected where possible, and whatever cannot be saved must be degraded. Helper proteins called chaperones support folding. Degradation is handled by the ubiquitin-proteasome system and by autophagy. With age the capacity of all these components declines. Misfolded proteins then remain more often and can clump into aggregates that are hard to break down.

A link exists, but its significance is contested. In Alzheimer’s, amyloid beta deposits outside cells while tau protein forms tangles inside them. Both are misfolding products that functioning quality control should intercept. Two things argue against reading this as the sole cause. First, amyloid plaques are also found in substantial quantity in older people without cognitive impairment. Second, while anti-amyloid antibodies remove plaques reliably, the effect on cognitive trajectory in the licensing trials remains small and comes with relevant side effects. Protein aggregation is therefore involved but does not fully explain the disease.

Not in a living person. Chaperone capacity and proteasome throughput can be determined in cell culture and tissue samples, but not through a blood test in preventive care. Values such as total protein, albumin or an amino acid analysis describe protein supply and the synthetic capacity of the liver. They are medically useful but say nothing about folding quality inside cells. Targeted searching happens only on concrete suspicion, for example serum electrophoresis when light-chain amyloidosis is suspected. Offers promising to determine your proteostasis have no basis for it.

Not demonstrated in humans. The stimuli discussed are chiefly those that activate stress responses in model organisms: endurance training, heat exposure such as sauna, and periods without food intake that promote autophagy. For sauna and for physical activity there are observational data with favourable associations to cardiovascular health. That these effects arise through improved proteostasis is a plausible assumption without direct evidence. These measures remain sensible for other, well-documented reasons. A capsule claiming to activate chaperones, by contrast, has no evidence base.