Binding of a small molecule at a protein-protein interface regulates the chaperone activity of hsp70-hsp40

ACS Chem Biol. 2010 Jun 18;5(6):611-22. doi: 10.1021/cb1000422.


Heat shock protein 70 (Hsp70) is a highly conserved molecular chaperone that plays multiple roles in protein homeostasis. In these various tasks, the activity of Hsp70 is shaped by interactions with co-chaperones, such as Hsp40. The Hsp40 family of co-chaperones binds to Hsp70 through a conserved J-domain, and these factors stimulate ATPase and protein-folding activity. Using chemical screens, we identified a compound, 115-7c, which acts as an artificial co-chaperone for Hsp70. Specifically, the activities of 115-7c mirrored those of a Hsp40; the compound stimulated the ATPase and protein-folding activities of a prokaryotic Hsp70 (DnaK) and partially compensated for a Hsp40 loss-of-function mutation in yeast. Consistent with these observations, NMR and mutagenesis studies indicate that the binding site for 115-7c is adjacent to a region on DnaK that is required for J-domain-mediated stimulation. Interestingly, we found that 115-7c and the Hsp40 do not compete for binding but act in concert. Using this information, we introduced additional steric bulk to 115-7c and converted it into an inhibitor. Thus, these chemical probes either promote or inhibit chaperone functions by regulating Hsp70-Hsp40 complex assembly at a native protein-protein interface. This unexpected mechanism may provide new avenues for exploring how chaperones and co-chaperones cooperate to shape protein homeostasis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Escherichia coli / chemistry
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Gene Expression Regulation, Fungal / drug effects
  • HSP40 Heat-Shock Proteins / metabolism*
  • HSP70 Heat-Shock Proteins / chemistry
  • HSP70 Heat-Shock Proteins / genetics
  • HSP70 Heat-Shock Proteins / metabolism*
  • Models, Molecular
  • Mutagenesis, Site-Directed
  • Protein Binding
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology*


  • Escherichia coli Proteins
  • HSP40 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins
  • Saccharomyces cerevisiae Proteins
  • Small Molecule Libraries
  • dnaK protein, E coli