Helicobacter pylori inhibits the cleavage of TRAF1 via a CagA-dependent mechanism

Figure 1 Tumor necrosis factor receptor-associated factor 1 is cleaved via caspase-8 in AGS cells infected with Helicobacter pylori. A: AGS cells transfected with either HA-tagged tumor necrosis factor receptor-associated factor 1 (TRAF1) or empty vector were treated with the apoptosis inducer (0.3 μg/mL CHX and 80 ng/mL TNF-α) for 6 h, and the cleavage of TRAF1 was detected by western blotting; B: AGS cells were transfected with wild-type or D163A mutant of TRAF1 and analyzed for the cleavage of TRAF1 by western blotting; C: AGS cells transfected with the HA-tagged TRAF1 were pretreated with 20 μmol/L of Z-VAD-FMK, Z-IETD-FMK, or Z-YVAD-FMK for 30 min, followed by treatment with the apoptosis inducer for 6 h and then analyzed for the cleavage of TRAF1 by western blotting; D: AGS cells transfected with the HA-tagged TRAF1 were pretreated with 20 μmol/L of Z-VAD-FMK, Z-IETD-FMK, or Z-YVAD-FMK for 30 min, followed by infection with Helicobacter pylori strain NCTC11637 for 6 h and then analyzed for the cleavage of TRAF1 by western blotting.