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How Do Chaperones Protect a Cell's Proteins from Oxidative Damage?
Mantu Santra1, Ken A Dill2, Adam M R de Graff1
1Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794, USA.
Cell Systems
|June 11, 2018
Summary
Protein damage in aging is linked to disease. Our model shows unfolded proteins are most vulnerable, with dwell time, not stability, being key. DnaK is the main guardian chaperone.
Area of Science:
- Biochemistry
- Molecular Biology
- Systems Biology
Background:
- Protein damage accumulation is implicated in aging and age-related diseases.
- Understanding protein susceptibility and chaperone roles in proteostasis is crucial but poorly understood.
- Key questions involve identifying vulnerable protein conformations and primary guardian chaperones.
Purpose of the Study:
- To develop a system-wide model of Escherichia coli proteostasis.
- To predict how proteins with varying folding properties interact with chaperone concentrations.
- To identify major protein damage targets and key protective chaperones.
Main Methods:
- Developed a system-wide computational model for E. coli proteostasis.
- Predicted protein responses to different chaperone concentrations based on folding properties.
- Computed "damage fingerprints" to identify vulnerable protein conformations.
Main Results:
- Unfolded protein conformations were identified as the primary targets for damage.
- A protein's dwell time in an unfolded state, not its stability or folding difficulty, is the critical factor.
- DnaK was identified as the main guardian chaperone, as its client proteins remain unfolded longer than GroEL's clients.
- Cellular stress response capacity is more sensitive to DnaK levels.
Conclusions:
- Chaperones function as protectors, not recyclers, in maintaining proteostasis.
- System-wide modeling is essential for understanding cellular stress resistance.
- Designing effective chaperone-targeting drugs necessitates a whole-cell, system-wide modeling approach.