Proteostasis is adaptive: Balancing chaperone holdases against foldases

Cells face fluctuating conditions that affect protein folding. Prior research has shown that proteostasis systems adjust to maintain protein function. However, the precise mechanism for this adaptation remains unclear. No prior work had resolved how cells balance folding and holding chaperones. This gap motivated the exploration of a cost-benefit framework. Existing studies describe chaperone roles but lack a unified model. The question of how cells detect and respond to proteome stress persists. This paper introduces a biophysical model to explain proteostasis adaptation.

The aim is to determine how cells adjust proteostasis under varying conditions. The specific problem is understanding how chaperone expression changes with stress. The motivation comes from observing proteostasis shifts during aging and metabolism. The researchers propose a cost-benefit model to explain this adaptation. They seek to unify observations across organisms and growth states. This approach addresses the need for a generalizable framework. The model focuses on balancing foldase and holdase activity. The study tests whether this mechanism explains proteostasis flexibility.

The researchers developed a biophysical model of proteostasis adaptation. They analyzed chaperone expression data from multiple organisms. The model incorporates foldase and holdase interactions. They tested the model against proteostasis changes during aging. The approach includes comparing metabolic rates across species. The model calculates energy costs of folding versus holding. They validated predictions using existing experimental data. The framework integrates biophysical principles with biological observations.

The model successfully predicts foldase-holdase ratios in different conditions. It explains proteostasis shifts observed during aging in organisms. The findings align with metabolic rate differences across species. The model shows that holdases increase with slower growth rates. Foldase activity decreases under higher stress conditions. The energy cost of folding is minimized in the model's predictions. The results match experimental observations of proteostasis adaptation. The model provides a unified explanation for chaperone expression patterns.

The model proposes a cost-benefit mechanism for proteostasis adaptation. The findings suggest that cells balance foldase and holdase activity. This mechanism explains proteostasis changes across organisms and ages. The model aligns with observed metabolic rate differences. The researchers propose that this framework captures proteostasis flexibility. The study does not claim this is the only mechanism for adaptation. The model provides a generalizable explanation for chaperone expression. The authors suggest this approach could guide future studies on proteostasis.