Identification of Inducers of the Yersinia enterocolitica Phage Shock Protein System and Comparison to the Regulation of the RpoE and Cpx Extracytoplasmic Stress Responses

Abstract

Known inducers of the phage shock protein (Psp) system suggest that it is an extracytoplasmic stress response, as are the well-studied RpoE and Cpx systems. However, a random approach to identify conditions and proteins that induce the Psp system has not been attempted. It is also unknown whether the proteins or mutations that induce Psp are specific or if they also activate the RpoE and Cpx systems. This study addressed these issues for the Yersinia enterocolitica Psp system. Random transposon mutagenesis identified null mutations and overexpression mutations that increase ⌽(pspA-lacZ) operon fusion expression. The results suggest that Psp may respond exclusively to extracytoplasmic stress. Null mutations affected glucosamine-6-phosphate synthetase (glmS), which plays a role in cell envelope biosynthesis, and the F 0 F 1 ATPase (atp operon). The screen also revealed that in addition to several secretins, the overexpression of three novel putative inner membrane proteins ( Misfolding and/or mislocalization of envelope proteins induce extracytoplasmic stress responses in bacteria. The RpoE and Cpx systems of Escherichia coli and its relatives are wellstudied examples (reviewed in references 41 and 42). These systems control many genes, with some overlap between their regulons, which encode proteases, envelope protein folding factors, and several proteins of unknown function (10,41,43). Mounting a response to extracytoplasmic stress is extremely important. rpoE is an essential gene in E. coli (14) and Yersinia enterocolitica (21), although this is apparently not the case in the closely related Salmonella genus (23).The RpoE response is important for virulence in Salmonella enterica serovar Typhimurium (23,45) and Vibrio cholerae (30). In addition, the RpoE and Cpx responses are induced by the overproduction of P pilus subunits from uropathogenic E. coli (25), and the Cpx system affects assembly and expression of the P pilus (24). The Cpx system is also important for the attachment of E. coli to surfaces (37), which is a critical step during biofilm formation.The phage shock protein (Psp) system may be another example of an extracytoplasmic stress response. pspA operon expression, studied most extensively in E. coli K-12, is induced by the mislocalization of secretin proteins and by environmental conditions that induce the RpoE response (reviewed in reference 35).

The Yersinia pseudotuberculosis and Yersinia pestis toxin complex is active against cultured mammalian cells

“…The mutation method was a variation on the l-Red recombinase method (Datsenko & Wanner, 2000) and utilized plasmid pAJD434, which has been optimized for efficiency in Yersinia ssp. (Maxson & Darwin, 2004). Plasmids and primers used for the mutant generation are listed in Table 1.…”

The importance of the Rcs phosphorelay in the survival and pathogenesis of the enteropathogenic yersiniae

“…The mutation method was a variation on the l-Red recombinase method (Datsenko & Wanner, 2000) and utilized plasmid pAJD434, which has been optimized for efficiency in Yersinia spp. (Maxson & Darwin, 2004). Plasmids and primers used for the mutant generation are listed in Table 1.…”

Multiple promoters control expression of the Yersinia enterocolitica phage-shock-protein A (pspA) operon

“…Recently, specific induction of Y. enterocolitica pspA operon expression was observed following overexpression of secretins and some cytoplasmic membrane proteins, and upon disruption of the F 0 F 1 -ATPase (Maxson & Darwin, 2004). The Psp system of Y. enterocolitica is also essential for virulence in a mouse model of infection (Darwin & Miller, 1999, 2001.…”