FIG. 5.

At equivalent levels of expression the full-length hsp70 protein provides protection whereas the protein with ATPase deleted does not. The HSP70 (clone 8-17) and HSP70ΔATPase cell lines were incubated for 24 h with various doses of doxycycline ([DOX]) ranging from 100 to 1,000 ng/ml and then examined for GFP fluorescence by flow cytometry (A), expressed protein levels by Western blotting (B), and resistance to heat-induced apoptosis (D) as described for Fig. 4. Quantitation of the Western blot (C) and comparison to the percent viabilities after heat shock (E) reveal that the full-length hsp70 protein protects cells from apoptosis when expressed at a level equal to the maximum level attained in the HSP70ΔATPase cell line and that the protein with ATPase deleted does not protect cells at any of the expressed levels.