Hsp70 selectively reduced the levels of the cytosolic forms of PrP mutants. A and B. Western blots. HEK293 (A) and N2a cells (B) were transiently co-transfected with pEGFP-Hsp70 and various PrP-plasmids. Twenty-four hours after transfection, the cells were treated with or without geldanamycin (1 μM) for an additional 24 h. The cells were harvested and examined separately by Western blot analysis using PrP- or Hsp70-specific antibodies. C and D. Quantification of the immunoblots. The numerical gray values for PrP were quantified and normalized to β-actin levels in HEK293 cells (C) and N2a cells (D). All experiments presented in the figures were repeated independently 3 times with consistent results. Each data point represents the mean ± SEM of 3 independent experiments. Samples were considered statistically different from the controls when P < 0.05.