Fiber assembly by the chaperone–usher pathway

Sauer, Frederic G.; Remaut, Han; Hultgren, Scott J.; Waksman, Gabriel

doi:10.1016/j.bbamcr.2004.02.010

Cited by 179 publications

(163 citation statements)

References 59 publications

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“…A multitude of Gram-negative pathogens use the so-called chaperone-usher pathway for the assembly of adhesive fibers that participate in host-pathogen interactions critical for infection (1,2). Among those fibers, P and type 1 pili, produced by uropathogenic strains of Escherichia coli (UPEC), have served as model systems to understand their structure and function.…”

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confidence: 99%

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Rationally designed small compounds inhibit pilus biogenesis in uropathogenic bacteria

Pinkner

Remaut

Buelens

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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268

245

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A chemical synthesis platform with broad applications and flexibility was rationally designed to inhibit biogenesis of adhesive pili assembled by the chaperone-usher pathway in Gram-negative pathogens. The activity of a family of bicyclic 2-pyridones, termed pilicides, was evaluated in two different pilus biogenesis systems in uropathogenic Escherichia coli. Hemagglutination mediated by either type 1 or P pili, adherence to bladder cells, and biofilm formation mediated by type 1 pili were all reduced by Ϸ90% in laboratory and clinical E. coli strains. The structure of the pilicide bound to the P pilus chaperone PapD revealed that the pilicide bound to the surface of the chaperone known to interact with the usher, the outer-membrane assembly platform where pili are assembled. Point mutations in the pilicide-binding site dramatically reduced pilus formation but did not block the ability of PapD to bind subunits and mediate their folding. Surface plasmon resonance experiments confirmed that the pilicide interfered with the binding of chaperone-subunit complexes to the usher. These pilicides thus target key virulence factors in pathogenic bacteria and represent a promising proof of concept for developing drugs that function by targeting virulence factors.antimicrobials ͉ chaperone-usher pathway ͉ pilicide ͉ urinary tract infection

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confidence: 99%

“…Cognate periplasmic chaperones are required for folding, stabilization, and transport of pilus subunits across the periplasm (1). PapD is the prototypic periplasmic chaperone and is required for P pilus assembly.…”

mentioning

confidence: 99%

Rationally designed small compounds inhibit pilus biogenesis in uropathogenic bacteria

Pinkner

Remaut

Buelens

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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268

245

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“…The cell envelope of Gram-negative bacteria contains a vast array of protein machineries dedicated to the translocation of polypeptides across the cytoplasmic membrane, periplasm, and outer membrane (OM) 3 (1,2). Some of these complexes also participate in the assembly of surface-exposed appendages, such as flagella and pili (fimbriae).…”

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confidence: 99%

“…The P pilus is composed of multiple subunits of PapA, which form a rigid helical rod. A thin linear tip fibrillum is located at the distal end of the pilus and is made of four different subunits (PapK, PapF, PapE, and the adhesin PapG) that assemble in a precise order and stoichiometry (3). The minor pilin, PapH, anchors the pilus rod to the cell surface (7).…”

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confidence: 99%

Modulating Effects of the Plug, Helix, and N- and C-terminal Domains on Channel Properties of the PapC Usher

Mapingire

Henderson

Duret

et al. 2009

Journal of Biological Chemistry

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The chaperone/usher system is one of the best characterized pathways for protein secretion and assembly of cell surface appendages in Gram-negative bacteria. In particular, this pathway is used for biogenesis of the P pilus, a key virulence factor used by uropathogenic Escherichia coli to adhere to the host urinary tract. The P pilus individual subunits bound to the periplasmic chaperone PapD are delivered to the outer membrane PapC usher, which serves as an assembly platform for subunit incorporation into the pilus and secretion of the pilus fiber to the cell surface. PapC forms a dimeric, twin pore complex, with each monomer composed of a 24-stranded transmembrane ␤-barrel channel, an internal plug domain that occludes the channel, and globular N-and C-terminal domains that are located in the periplasm. Here we have used planar lipid bilayer electrophysiology to characterize the pore properties of wild type PapC and domain deletion mutants for the first time. The wild type pore is closed most of the time but displays frequent short-lived transitions to various open states. In comparison, PapC mutants containing deletions of the plug domain, an ␣-helix that caps the plug domain, or the N-and C-terminal domains form channels with higher open probability but still exhibiting dynamic behavior. Removal of the plug domain results in a channel with extremely large conductance. These observations suggest that the plug gates the usher channel closed and that the periplasmic domains and ␣-helix function to modulate the gating activity of the PapC twin pore.The cell envelope of Gram-negative bacteria contains a vast array of protein machineries dedicated to the translocation of polypeptides across the cytoplasmic membrane, periplasm, and outer membrane (OM) 3 (1, 2). Some of these complexes also participate in the assembly of surface-exposed appendages, such as flagella and pili (fimbriae). One of the most thoroughly studied secretion systems is the chaperone/usher pathway, responsible for the biogenesis of a superfamily of virulenceassociated surface structures, including P and type 1 pili (3). These pili play essential roles in the pathogenesis of uropathogenic Escherichia coli by providing a tool for attachment of the bacteria to host urothelial cells (4 -6). P pili, encoded by the chromosomal pap gene cluster, are critical virulence factors for infection of the kidney by uropathogenic E. coli and the development of pyelonephritis. The P pilus is composed of multiple subunits of PapA, which form a rigid helical rod. A thin linear tip fibrillum is located at the distal end of the pilus and is made of four different subunits (PapK, PapF, PapE, and the adhesin PapG) that assemble in a precise order and stoichiometry (3). The minor pilin, PapH, anchors the pilus rod to the cell surface (7).The pilus subunits are first translocated through the cytoplasmic membrane via the Sec general secretory pathway (8). Once in the periplasm, the subunits form binary complexes with the PapD chaperone. The details of the binding interact...

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“…It consists of a cylindrical rod with a thinner, flexible tip fibrillum capped by an adhesin. The P pilus is assembled by the highly conserved chaperone-usher pathway (8). Newly synthesized pilus subunits are translocated to the periplasm by the secretion machinery where they are met by the specialized chaperone PapD, which both catalyzes folding of individual subunits and delivers them to the PapC usher, the outer membrane assembly site (9).…”

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confidence: 99%

The extracytoplasmic adaptor protein CpxP is degraded with substrate by DegP

Isaac

Pinkner²,

Hultgren³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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175

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In Escherichia coli, the CpxR͞A two-component system senses various types of extracytoplasmic stresses and responds by activating the expression of genes encoding periplasmic protein folding and trafficking factors that clear such stresses to ensure the organism's survival. The cpxP gene encodes a small, stresscombative periplasmic protein and is the most strongly induced member of the Cpx regulon. We demonstrate that the Cpx stress response suppresses the toxicity associated with two misfolded proteins derived from the P pilus of uropathogenic E. coli and that mutations in either cpxP or the gene for the periplasmic protease DegP prevent suppression by preventing the degradation of these proteins. Strikingly, the presence of a periplasmic misfolded protein substrate significantly enhances the proteolysis of CpxP by DegP. Our data suggest that CpxP functions as a periplasmic adaptor protein that is required for the effective proteolysis of a subset of misfolded substrates by the DegP protease.Escherichia coli ͉ misfolded protein ͉ periplasm ͉ regulated proteolysis

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Fiber assembly by the chaperone–usher pathway

Cited by 179 publications

References 59 publications

Rationally designed small compounds inhibit pilus biogenesis in uropathogenic bacteria

Rationally designed small compounds inhibit pilus biogenesis in uropathogenic bacteria

Modulating Effects of the Plug, Helix, and N- and C-terminal Domains on Channel Properties of the PapC Usher

The extracytoplasmic adaptor protein CpxP is degraded with substrate by DegP

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