Fig. 6

IGFBP2 forms a complex with EGFR and DNA-PKcs in the EAC cells in response to acidic bile salts. a (FLO1) and b (OE33) cells were treated with acidic bile salts (ABS, pH 4, 200 μM) for 20 min and then recovered for 0.5 h. Co-immunoprecipitation was performed using antibodies against EGFR, DNA-PKcs, and IGFBP2. Westering blot analysis was used to detect the indicated proteins. DNA-PKcs was not detected in IGFBP2 immunoprecipitation blots, possibly due to the large size of DNA-PKcs protein (450 kDa) that cannot be efficiently pulled down by the relatively small IGFBP2 (35 kDa). c, FLO1 cells with IGFBP2 knockdown (si-IGFBP2) and control cells were treated with ABS for 20 min and then recovered for 0.5 h. Co-immunoprecipitation was performed using an antibody against EGFR. Westering blot analysis was used to detect the indicated proteins. IgG was used as the negative control. UT, untreated with ABS