FIGURE 5.

Effect of Hsp90 inhibitors on H1R signaling. A, effect of 17-AAG on PMA-induced up-regulation of H1R gene expression in HeLa cells. B, effect of 17-AAG on PMA-induced phosphorylation of PKCδ on Tyr³¹¹. C, effect of 17-AAG on translocation of PKCδ in response to PMA stimulation. D and E, effect of celastrol (D) or novobiocin (E) on PMA-induced up-regulation of H1R gene expression in HeLa cells. HeLa cells were serum-starved for 24 h and treated with varying concentrations of 17-AAG (A–C), celastrol (D), or novobiocin (E) for 24 h before stimulation with PMA for 3 h (A, D, and E), 10 min (B), or 5 min (C). In B and C, 1 μm 17-AAG was used. In A, D, and E, total RNA was isolated, and the H1R mRNA levels were determined by real-time RT-PCR. Data are presented as the mean ± S.E. (error bars) (n = 3). **, p < 0.01; *, p < 0.05 versus PMA. In B, total cell lysates were prepared and subjected to immunoblot analysis. In C, the subcellular localization of PKCδ was determined using a confocal laser microscope. The images of control and PMA stimulation were taken from Ref. 14. Scale bars, 20 μm.