Figure 1.

High-throughput ATPase screen identifies inhibitors and activators of the Hsp72/DnaJA2/BAG2 system. A, schematic of the Hsp72 ATPase cycle, highlighting the role of the DnaJA2 and BAG2 co-chaperones. Hsp72 (0.5 μm) has a slow hydrolysis rate in the absence of DnaJA2 (0.1 μm) or BAG2 (0.25 μm). Results are the average of triplicates, and the error bars represent standard error of the mean (S.E.). B, overview of the HTS campaign. A total of 100,000 molecules were screened against the Hsp72/DnaJA2/BAG2 combination. Approximately 1.8% of the molecules had inhibitor or activator activity at ±1 S.D., and 1.1% were inhibitors or activators at ±3 S.D. After triage for fluorescent artifacts and dose-response curves (EC₅₀ <50 μm), 74 molecules were predicted to be inhibitors. See the text and under “Materials and methods” for details. C, overview of the compounds with activity at ±1 S.D. and ±3 S.D. from the controls, highlighting the distribution of the top active molecules.