Figure 7. ERp57 triggers proliferation via mTOR activation in a p53-independent manner.

A. HCT116 shERp57 p53 +/+ and p53 −/− cells were exposed to 3 Gy 24 h after induction of ERp57 knockdown. 72 h after irradiation cell lysates were subjected to Western blotting. mTOR activity was monitored via phosphorylation status of p70S6K at Thr389. As a positive control cells were treated with 1 μM insulin for 1 h. B. HCT116 shERp57 p53 +/+ and p53 −/− cells were treated with 3 Gy 4 days after knockdown induction. Following treatment cells were reseeded. Cell counts were determined when the control samples were grown to confluency and normalized to non-induced controls. Images of representative samples taken prior to cell number determination are shown for each subfigure (lower panel). C. Colony formation assay of HCT116 p53 +/+ cells. After induction of ERp57 knockdown, cells were irradiated with 1 or 3 Gy and incubated for 10–14 days.