Asymmetric deceleration of ClpB or Hsp104 ATPase activity unleashes protein-remodeling activity.
Two members of the AAA+ superfamily, ClpB and Hsp104, collaborate with Hsp70 and Hsp40 to rescue aggregated proteins. However, the mechanisms that elicit and underlie their protein-remodeling activities remain unclear. We report that for both Hsp104 and ClpB, mixtures of ATP and ATP-gammaS unexpectedly unleash activation, disaggregation and unfolding activities independent of cochaperones. Mutations reveal how remodeling activities are elicited by impaired hydrolysis at individual nucleotide-binding domains. However, for some substrates, mixtures of ATP and ATP-gammaS abolish remodeling, whereas for others, ATP binding without hydrolysis is sufficient. Remodeling of different substrates necessitates a diverse balance of polypeptide 'holding' (which requires ATP binding but not hydrolysis) and unfolding (which requires ATP hydrolysis). We suggest that this versatility in reaction mechanism enables ClpB and Hsp104 to reactivate the entire aggregated proteome after stress and enables Hsp104 to control prion inheritance.
Doyle
Shannon M
SM
Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health (NIH), Bethesda, Maryland 20892, USA.
Shorter
James
J
Zolkiewski
Michal
M
Hoskins
Joel R
JR
Lindquist
Susan
S
Wickner
Sue
S
D000251:Adenosine Triphosphatases / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000737:chemistry; D049071:Endopeptidase Clp; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics; D006868:Hydrolysis; D008958:Models, Molecular; D009154:Mutation; D010454:Peptide Termination Factors; D011328:Prions / Q000737:chemistry; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*
D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C070972:HsP104 protein, S cerevisiae; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C069775:ClpB protein, E coli