Fig. 4. Cellular distribution of GFP-Hsp70 and GFP-Hsp70(K71E) in control and heat-shocked cells. HeLa cells transfected with GFP-Hsp70 (Fig. 4A) or GFP-Hsp70(K71E) (Fig. 4B) were imaged before (black bars) and immediately following (white bars) heat shock. The average fluorescence intensities of the cytosol and the nucleus were measured and the ratio of the fluorescence of the nucleus relative to the cytosol was calculated. A minimum of 250 cells per experimental condition were imaged and the percent of cells with each Hsp70 distribution range was determined. Hsp70 distribution was calculated as percentage of the total cells imaged.