Comparative Analysis of Type III Effector Translocation byYersinia pseudotuberculosisExpressing Native LcrV or PcrV fromPseudomonas aeruginosa

The homologues LcrV of Yersinia species and PcrV of Pseudomonas aeruginosa are pore-forming components. When expressed in a Yersinia lcrV background, PcrV formed smaller pores in infected erythrocyte membranes, correlating to a lowered translocation of Yersinia effectors. To understand this phenomenon, cytotoxins exoenzyme S of P. aeruginosa and YopE of Yersinia were introduced into a Yersinia background without Yop effectors but expressing LcrV or PcrV. Comparable translocation of each substrate indicated that substrate recognition by LcrV/PcrV is not a regulator of translocation. Yersinia harboring pcrV coexpressed with its native operon efficiently translocated effectors into HeLa cell monolayers and formed large LcrV-like pores in erythrocyte membranes. Thus, a PcrV complex with native P. aeruginosa translocon components is required to form fully functional pores for complete complementation of effector translocation in Yersinia.