Relative importance of three iron-regulated outer membrane proteins for in vivo growth of Vibrio cholerae.

Enteropathogenic Escherichia coli grow as discrete colonies on the mucous membranes of the small intestine. A similar pattern can be demonstrated in vitro; termed localized adherence (LA), it is characterized by the presence of circumscribed clusters of bacteria attached to the surfaces of cultured epithelial cells. The LA phenotype was studied using B171, an O111:NM enteropathogenic E. coli (EPEC) strain, and HEp-2 cell monolayers. LA could be detected 30-60 min after exposure of HEp-2 cells to B171. However, bacteria transferred from infected HEp-2 cells to fresh monolayers exhibited LA within 15 min, indicating that LA is an inducible phenotype. Induction of the LA phenotype was found to be associated with de novo protein synthesis and changes in the outer membrane proteins, including the production of a new 18.5-kD polypeptide. A partial NH2-terminal amino acid sequence of this polypeptide was obtained and showed it to be identical through residue 12 to the recently described bundle-forming pilus subunit of EPEC. Expression of the 18.5-kD polypeptide required the 57-megadalton enteropathogenic E. coli adherence plasmid previously shown to be required for the LA phenotype in vitro and full virulence in vivo. This observation, the correspondence of the 18.5-kD polypeptide to an EPEC-specific pilus protein, and the temporal correlation of its expression with the development of the LA phenotype suggest that it may contribute to the EPEC colonial mode of growth.

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In vivo expression of iron regulated outer-membrane proteins in Pasteurella haemolytica-A1

Microbial Pathogenesis ◽

10.1016/0882-4010(91)90023-4 ◽

1991 ◽

Vol 11 (5) ◽

pp. 373-378 ◽

Cited By ~ 22

Author(s):

Douglas W. Morck ◽

Brian D. Ellis ◽

P.A.Gilbert Domingue ◽

Merle E. Olson ◽

J.William Costerton

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Outer Membrane Proteins ◽

Pasteurella Haemolytica ◽

In Vivo Expression

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Proteomic analysis of Proteus mirabilis outer membrane proteins reveals differential expression in vivo vs. in vitro conditions

FEMS Immunology & Medical Microbiology ◽

10.1111/j.1574-695x.2011.00839.x ◽

2011 ◽

Vol 63 (2) ◽

pp. 174-182 ◽

Cited By ~ 5

Author(s):

Bruno D'Alessandro ◽

Leticia M. S. Lery ◽

Wanda M. A. Krüger ◽

Analía Lima ◽

Claudia Piccini ◽

...

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Differential Expression ◽

Proteus Mirabilis ◽

Proteomic Analysis ◽

Outer Membrane Proteins

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The CpxQ sRNA Negatively Regulates Skp To Prevent Mistargeting of β-Barrel Outer Membrane Proteins into the Cytoplasmic Membrane

mBio ◽

10.1128/mbio.00312-16 ◽

2016 ◽

Vol 7 (2) ◽

Cited By ~ 27

Author(s):

Marcin Grabowicz ◽

Daria Koren ◽

Thomas J. Silhavy

Keyword(s):

Stress Response ◽

Membrane Proteins ◽

Outer Membrane ◽

Protein Misfolding ◽

Outer Membrane Proteins ◽

Inner Membrane ◽

Bam Complex ◽

Envelope Stress ◽

Periplasmic Chaperone

ABSTRACT The promoter most strongly induced upon activation of the Cpx two-component envelope stress response is the cpxP promoter. The 3′ untranscribed region (UTR) of the cpxP transcript is shown to produce a small RNA (sRNA), CpxQ. We investigated the role of CpxQ in combating envelope stress. Remarkably, the two effectors specified by the transcript are deployed to combat distinct stresses in different cellular compartments. CpxP acts in both a regulatory negative-feedback loop and as an effector that combats periplasmic protein misfolding. We find that CpxQ combats toxicity at the inner membrane (IM) by downregulating the synthesis of the periplasmic chaperone Skp. Our data indicate that this regulation prevents Skp from inserting β-barrel outer membrane proteins (OMPs) into the IM, a lethal event that likely collapses the proton motive force. Our findings suggest that Skp can fold and directly insert OMPs into a lipid bilayer in vivo without the aid of the Bam complex. IMPORTANCE Skp is a well-characterized periplasmic chaperone that binds unfolded OMPs. Surprisingly, we find that Skp can catalyze the folding and mistargeting of OMPs into the inner membrane without the aid of the other cellular proteins that normally assemble OMPs. Several OMPs function as diffusion pores. Accordingly, their mistargeting is lethal because it depolarizes the inner membrane. We show that the most highly expressed transcript of the Cpx stress response produces an sRNA from the 3′ UTR, CpxQ, which combats this potential toxicity by downregulating Skp production. Defects in OMP assembly trigger the σ E response to upregulate factors, including Skp, that promote OMP folding. The Cpx response downregulates σ E . Our findings reveal that this heretofore puzzling hierarchy exists to protect the inner membrane.

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Composition and immunochemical properties of outer membrane proteins of Vibrio cholerae.

Journal of Bacteriology ◽

10.1128/jb.144.1.382-389.1980 ◽

1980 ◽

Vol 144 (1) ◽

pp. 382-389 ◽

Cited By ~ 23

Author(s):

S Kabir

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Vibrio Cholerae ◽

Outer Membrane Proteins

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Characterization of Two Outer Membrane Proteins, FlgO and FlgP, That Influence Vibrio cholerae Motility

Journal of Bacteriology ◽

10.1128/jb.00632-09 ◽

2009 ◽

Vol 191 (18) ◽

pp. 5669-5679 ◽

Cited By ~ 29

Author(s):

Raquel M. Martinez ◽

Madushini N. Dharmasena ◽

Thomas J. Kirn ◽

Ronald K. Taylor

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Vibrio Cholerae ◽

Outer Membrane Proteins ◽

Sigma 54 ◽

Colonization Factor ◽

Motile Cells ◽

Outer Membrane Lipoprotein ◽

Important Virulence Factor

ABSTRACT Vibrio cholerae is highly motile by the action of a single polar flagellum. The loss of motility reduces the infectivity of V. cholerae, demonstrating that motility is an important virulence factor. FlrC is the sigma-54-dependent positive regulator of flagellar genes. Recently, the genes VC2206 (flgP) and VC2207 (flgO) were identified as being regulated by FlrC via a microarray analysis of an flrC mutant (D. C. Morris, F. Peng, J. R. Barker, and K. E. Klose, J. Bacteriol. 190:231-239, 2008). FlgP is reported to be an outer membrane lipoprotein required for motility that functions as a colonization factor. The study reported here focuses on the characterization of flgO, the first gene in the flgOP operon. We show that FlgO and FlgP are important for motility, as strains with mutations in the flgOP genes have reduced motility phenotypes. The flgO and flgP mutant populations display fewer motile cells as well as reduced numbers of flagellated cells. The flagella produced by the flgO and flgP mutant strains are shorter in length than the wild-type flagella, which can be restored by inhibiting rotation of the flagellum. FlgO is an outer membrane protein that localizes throughout the membrane and not at the flagellar pole. Although FlgO and FlgP do not specifically localize to the flagellum, they are required for flagellar stability. Due to the nature of these motility defects, we established that the flagellum is not sufficient for adherence; rather, motility is the essential factor required for attachment and thus colonization by V. cholerae O1 of the classical biotype. This study reveals a novel mechanism for which the outer membrane proteins FlgO and FlgP function in motility to mediate flagellar stability and influence attachment and colonization.

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