Yersinia enterocolitica induces apoptosis in macrophages by a process requiring functional type III secretion and translocation mechanisms and involving YopP, presumably acting as an effector protein.

Yersiniae, causative agents of plague and gastrointestinal diseases, secrete and translocate Yop effector proteins into the cytosol of macrophages, leading to disruption of host defense mechanisms. It is shown in this report that Yersinia enterocolitica induces apoptosis in macrophages and that this effect depends on YopP. Functional secretion and translocation mechanisms are required for YopP to act, strongly suggesting that this protein exerts its effect intracellularly, after translocation into the macrophages. YopP shows a high level of sequence similarity with AvrRxv, an avirulence protein from Xanthomonas campestris, a plant pathogen that induces programmed cell death in plant cells. This indicates possible similarities between the strategies used by pathogenic bacteria to elicit programmed cell death in both plant and animal hosts.