Mammalian apoptosis-inducing protein, HAP, induces bacterial cell death

In attempting to produce the HAP, endoplasmic reticulum (ER) targeted apoptosis-inducing protein, as a GST-fusion protein we found that the expression of HAP, but not GST alone, induced bacterial cell death. The HAP protein inhibited the bacterial growth within 30 min after inducting HAP expression. The transmission electron microscopic examination revealed that the morphology of the bacterial cells expressing hap was changed dramatically: unusually elongated phenotype compared with those of controls and finally leading to cell death. The lethality of HAP was relieved by the addition of vitamin E as a reducing agent and under anaerobic growth conditions. These results suggest that a trace amount of HAP induces bacterial cell death and the death is related with reactive oxygen species (ROS).