HSP72 Protects Cells from ER Stress-induced Apoptosis via Enhancement of IRE1α-XBP1 Signaling through a Physical Interaction (original) (raw)
Figure 6
The ATPase domain of Hsp72 is necessary for activation of IRE1α/XBP1 axis and inhibition of ER stress-induced apoptosis.
(A) The control (Neo), wild-type Hsp72, and ΔATPase Hsp72 expressing PC12 cells were treated with (0.25 µM) Tg for 12 h and the expression levels of indicated genes were quantified by real-time RT-PCR, normalizing against GAPDH. Average and error bars represent mean ± SD from two independent experiments performed in triplicate. ** indicates a statistical significance between Hsp72 and Hsp72 ΔATPase cells; p<0.005. (B) The control (Neo), wild-type Hsp72, and ΔATPase Hsp72 expressing PC12 cells were either untreated (Un) or treated (0.25 µM) Tg or (2 µg/ml) Tm for 48 h, and cell viability was determined using MTT assay. Average and error bars represent mean ± SD from three independent experiments performed in triplicate. ** indicates a statistical significance between Hsp72 and Hsp72 ΔATPase cells; p<0.005. (C) The control (Neo), wild-type Hsp72, and ΔATPase Hsp72 expressing PC12 cells were treated as in (B), and DEVDase activity was measured as described in Materials and Methods. Average and error bars represent mean ± SD from four independent experiments performed in duplicate. ** indicates a statistical significance between Hsp72 and Hsp72 ΔATPase cells; p<0.005.