FIG. 8.

Effects of CHIP on ATPase activities and nucleotide binding of heat shock proteins. (A) The ATPase activities of Hsc70 (black bars) and Hsp70 (white bars) were measured over 20 min in the presence or absence of CHIP, Hsp40, and/or Hsp90 as indicated. Data were normalized to the ATPase activity of Hsc70 alone. ∗ (or †) indicates a significant difference (P < 0.05) between the ATPase activity of Hsc70 alone (or Hsp70 alone) and Hsc70 plus Hsp40 (or Hsp70 plus Hsp40). ∗∗ (or ††) indicates a significant difference (P < 0.05) between the ATPase activity of Hsc70 plus Hsp40 (or Hsp70 plus Hsp40) and Hsc70 plus Hsp40 plus CHIP (or Hsp70 plus Hsp40 plus CHIP). Each condition was repeated for a total of six replicates. (B) The nucleotide species bound to Hsc70 in the absence or presence of CHIP, Hsp40, and/or BAG-1 was determined by thin-layer chromatography. A representative autoradiograph is shown.