Snapshots of usher-mediated protein secretion and ordered pilus assembly

Saulino, Evan T.; Bullitt, Esther; Hultgren, Scott J.

doi:10.1073/pnas.160070497

Cited by 86 publications

(88 citation statements)

References 38 publications

(80 reference statements)

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“…on May 11, 2018 by guest http://jb.asm.org/ type 1 pili demonstrated that chaperone-subunit complexes could be purified from the OM as a complex with the FimD usher (27,28). We coexpressed WT PapC or PapC⌬2-11 with the PapD chaperone and the tip fibril subunits PapK, -E, -F, and -G. OM fractions from these bacteria were isolated and solubilized with the nondenaturing detergent DDM, and PapC was purified by its His tag with nickel beads.…”

Section: Vol 186 2004 Function Of the Usher N Terminus In Pilus Biomentioning

confidence: 99%

The Usher N Terminus Is the Initial Targeting Site for Chaperone-Subunit Complexes and Participates in Subsequent Pilus Biogenesis Events

et al. 2004

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Pilus biogenesis on the surface of uropathogenic Escherichia coli requires the chaperone/usher pathway, a terminal branch of the general secretory pathway. In this pathway, periplasmic chaperone-subunit complexes target an outer membrane (OM) usher for subunit assembly into pili and secretion to the cell surface. The molecular mechanisms of protein secretion across the OM are not well understood. Mutagenesis of the P pilus usher PapC and the type 1 pilus usher FimD was undertaken to elucidate the initial stages of pilus biogenesis at the OM. Deletion of residues 2 to 11 of the mature PapC N terminus abolished the targeting of the usher by chaperone-subunit complexes and rendered PapC nonfunctional for pilus biogenesis. Similarly, an intact FimD N terminus was required for chaperone-subunit binding and pilus biogenesis. Analysis of PapC-FimD chimeras and N-terminal fragments of PapC localized the chaperone-subunit targeting domain to the first 124 residues of PapC. Single alanine substitution mutations were made in this domain that blocked pilus biogenesis but did not affect targeting of chaperone-subunit complexes. Thus, the usher N terminus does not function simply as a static binding site for chaperone-subunit complexes but also participates in subsequent pilus assembly events.

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Section: Vol 186 2004 Function Of the Usher N Terminus In Pilus Biomentioning

confidence: 99%

The Usher N Terminus Is the Initial Targeting Site for Chaperone-Subunit Complexes and Participates in Subsequent Pilus Biogenesis Events

et al. 2004

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“…The ushers (80 to 90 kDa) are somewhat larger than secretins. PapC, as well as its counterpart in type I pili secretion, FimD, forms ring-like structures, as shown by electron microscopy (579,655). These rings are 15 nm across and contain central pores 2 to 3 nm in diameter.…”

Section: Secretins Ushers and Autotransporters Producing Oligomericmentioning

confidence: 93%

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Nikaido

2003

Microbiol Mol Biol Rev

3,768

3,800

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Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a permeability barrier to prevent the entry of noxious compounds and at the same time to allow the influx of nutrient molecules. This review summarizes the development in the field since our previous review (H. Nikaido and M. Vaara, Microbiol. Rev. 49:1-32, 1985) was published. With the discovery of protein channels, structural knowledge enables us to understand in molecular detail how porins, specific channels, TonB-linked receptors, and other proteins function. We are now beginning to see how the export of large proteins occurs across the outer membrane. With our knowledge of the lipopolysaccharide-phospholipid asymmetric bilayer of the outer membrane, we are finally beginning to understand how this bilayer can retard the entry of lipophilic compounds, owing to our increasing knowledge about the chemistry of lipopolysaccharide from diverse organisms and the way in which lipopolysaccharide structure is modified by environmental conditions

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“…The helical shaft has a diameter of 7 nm and consists of 3.4 copies of the FimA major subunit per turn (42, 122). The short tip fibrillum is composed of the FimF and FimG minor fimbrial subunits and carries the FimH tip adhesin at its distal end (122,163,279,291).…”

Section: The ␥-Fimbriaementioning

confidence: 99%

Evolution of the Chaperone/Usher Assembly Pathway: Fimbrial Classification Goes Greek

Nuccio

Bäumler

2007

Microbiol Mol Biol Rev

293

456

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SUMMARY Many Proteobacteria use the chaperone/usher pathway to assemble proteinaceous filaments on the bacterial surface. These filaments can curl into fimbrial or nonfimbrial surface structures (e.g., a capsule or spore coat). This article reviews the phylogeny of operons belonging to the chaperone/usher assembly class to explore the utility of establishing a scheme for subdividing them into clades of phylogenetically related gene clusters. Based on usher amino acid sequence comparisons, our analysis shows that the chaperone/usher assembly class is subdivided into six major phylogenetic clades, which we have termed α-, β-, γ-, κ-, π-, and σ-fimbriae. Members of each clade share related operon structures and encode fimbrial subunits with similar protein domains. The proposed classification system offers a simple and convenient method for assigning newly discovered chaperone/usher systems to one of the six major phylogenetic groups.

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Snapshots of usher-mediated protein secretion and ordered pilus assembly

Cited by 86 publications

References 38 publications

The Usher N Terminus Is the Initial Targeting Site for Chaperone-Subunit Complexes and Participates in Subsequent Pilus Biogenesis Events

The Usher N Terminus Is the Initial Targeting Site for Chaperone-Subunit Complexes and Participates in Subsequent Pilus Biogenesis Events

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Evolution of the Chaperone/Usher Assembly Pathway: Fimbrial Classification Goes Greek

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