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Updated: Jul 14, 2026
08:58
In Situ Monitoring of Transiently Formed Molecular Chaperone Assemblies in Bacteria, Yeast, and Human Cells
Published on: September 2, 2019
Collaboration between the ClpB AAA+ remodeling protein and the DnaK chaperone system
Shannon M Doyle1, Joel R Hoskins, Sue Wickner
1Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Summary
Heat shock proteins ClpB and Hsp104 disaggregate proteins with the DnaK/Hsp70 system. These chaperones synergistically remodel proteins and dissolve aggregates, requiring ATP hydrolysis at both ClpB nucleotide-binding sites.
Area of Science:
- Molecular Biology
- Protein Homeostasis
- Cellular Stress Response
Background:
- ClpB and Hsp104 are AAA+ proteins that protect cells from heat stress.
- They form hexameric rings with two nucleotide-binding sites per monomer.
- Their role with the DnaK/Hsp70 system in protein disaggregation is not fully understood.
Purpose of the Study:
- To investigate the synergistic roles of ClpB and the DnaK chaperone system in protein remodeling.
- To understand the conditions under which ClpB alone elicits remodeling activity.
- To determine the requirement of ATP hydrolysis for ClpB and DnaK functional collaboration.
Main Methods:
- Studied ClpB and Hsp104 protein remodeling activity.
- Utilized a mixture of ATP and ATP gamma S to asymmetrically slow ATPase activity.
- Mutated one of the two nucleotide-binding domains in ClpB.
- Tested for stimulation by the DnaK chaperone system.
Main Results:
- ClpB and the DnaK system act synergistically to remodel proteins and dissolve aggregates.
- ATP hydrolysis is required for this synergistic activity.
- Both nucleotide-binding sites of ClpB must be capable of ATP hydrolysis for functional collaboration.
Conclusions:
- ClpB and the DnaK chaperone system exhibit synergistic protein remodeling and aggregate dissolution.
- Functional collaboration requires ATP hydrolysis at both nucleotide-binding sites of ClpB.
- This highlights the cooperative mechanism of chaperone systems in maintaining protein homeostasis.
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