Pilus retraction powers bacterial twitching motility

Merz, Alexey J.; So, Magdalene; Sheetz, Michael P.

doi:10.1038/35024105

Cited by 759 publications

(751 citation statements)

References 29 publications

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“…To initiate pilus assembly, the pilin subunit PilE, in its membrane bound state, is processed by the pre-pilin peptidase PilD, removing a short hydrophilic N-terminal peptide, and methylating the N-terminal amino acid (Nunn & Lory, 1991). Type IV pili are retractable, and this retraction process is responsible for the twitching motility of neisserial cells observed on solid media and mucosal epithelium (Merz et al, 2000). The cytoplasmic protein PilT is essential for retraction, but dispensable for pilus assembly (Wolfgang et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Topology of the outer-membrane secretin PilQ from Neisseria meningitidis

et al. 2006

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Neisseria meningitidis is the causative agent of epidemic meningococcal meningitis and septicaemia. Type IV pili are surface organelles that mediate a variety of functions, including adhesion, twitching motility, and competence for DNA binding and uptake in transformation. The secretin PilQ is required for type IV pilus expression at the cell surface, and forms a dodecameric cage-like macromolecular complex in the meningococcal outer membrane. PilQ-null mutants are devoid of surface pili, and prevailing evidence suggests that the PilQ complex facilitates extrusion and retraction of type IV pili across the outer membrane. Defining the orientation of the meningococcal PilQ complex in the membrane is a prerequisite for understanding the structure-function relationships of this important protein in pilus biology. In order to begin to define the topology of the PilQ complex in the outer membrane, polyhistidine insertions in N-and C-terminal regions of PilQ were constructed, and their subcellular locations examined. Notably, the insertion epitopes at residues 205 and 678 were located within the periplasm, whereas residue 656 was exposed at the outer surface of the outer membrane. Using electron microscopy with Ni-NTA gold labelling, it was demonstrated that the insertion at residue 205 within the N-terminus mapped to a site on the arm-like features of the 3D structure of the PilQ multimer. Interestingly, mutation of the same region gave rise to an increase in vancomycin permeability through the PilQ complex. The results yield novel information on the PilQ N-terminal location and function in the periplasm, and reveal a complex organization of the membrane-spanning secretin in vivo.

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Section: Introductionmentioning

confidence: 99%

Topology of the outer-membrane secretin PilQ from Neisseria meningitidis

et al. 2006

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“…Recently, the use of conditional double-knockout mutants has allowed the dissection of type IV pilus formation into three different phases -pilin processing, pilus formation and pilus extrusion (Wolfgang et al, 1998(Wolfgang et al, , 2000. To reveal these phases, it was essential to inactivate PilT, a putative ATP-binding protein involved in pilus retraction (Merz et al, 2000). This protein seems to act in quality control by preventing fibre formation and, in turn, minimizing growth defects that may occur in the absence of essential biogenesis components.…”

Section: Introductionmentioning

confidence: 99%

BfpU, a soluble protein essential for type IV pilus biogenesis in enteropathogenic Escherichia coli

et al. 2002

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A cluster of 14 genes located on the large plasmid of enteropathogenic Escherichia coli (EPEC) strains is sufficient to direct the biogenesis of the type IV bundle-forming pilus (BFP) in a recombinant E. coli host. The fifth gene in the cluster, bfpU, encodes a protein that is predicted to be localized to the periplasmic space. To determine whether BfpU is necessary for pilus biogenesis, the authors constructed a non-polar bfpU mutant EPEC strain by allelic exchange. The mutant strain was unable to perform localized adherence and auto-aggregation, two phenotypes associated with BFP expression, and it failed to make BFP. These phenotypes were restored to the bfpU mutant by a plasmid containing bfpU. There was no difference between the wild-type and bfpU mutant strains in their expression or processing of the pre-pilin protein or in their localization of the pilin protein in the inner and outer membranes. Fractionation studies revealed that BfpU is completely soluble and is detected in both the periplasm and the cytoplasm. Thus, BfpU represents a novel protein required for type IV pilus assembly.

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“…M. xanthus TFP were seen under EM as polar filaments measuring 5-7 nm in diameter and 4-10 m in length (19). Previous studies have revealed that TFP-dependent surface motilities are achieved through TFP extension and attachment to an external substrate followed by retraction, which pulls the cells forward (20)(21)(22). Extracellular fibril material has been visualized under SEM as 30-to 50-nm-thick intercellular fibers (23) that form a mesh-like network surrounding the cell body (24).…”

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confidence: 99%

Nanoscale visualization and characterization of Myxococcus xanthus cells with atomic force microscopy

Pelling

Shi

et al. 2005

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

111

109

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Multicellular microbial communities are the predominant form of existence for microorganisms in nature. As one of the most primitive social organisms, Myxococcus xanthus has been an ideal model bacterium for studying intercellular interaction and multicellular organization. Through previous genetic and EM studies, various extracellular appendages and matrix components have been found to be involved in the social behavior of M. xanthus, but none of them was directly visualized and analyzed under native conditions. Here, we used atomic force microscopy (AFM) imaging and in vivo force spectroscopy to characterize these cellular structures under native conditions. AFM imaging revealed morphological details on the extracellular ultrastructures at an unprecedented resolution, and in vivo force spectroscopy of live cells in fluid allowed us to nanomechanically characterize extracellular polymeric substances. The findings provide the basis for AFM as a useful tool for investigating microbial-surface ultrastructures and nanomechanical properties under native conditions. force spectroscopy ͉ nonomechanics ͉ bacteria ͉ swarm

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Pilus retraction powers bacterial twitching motility

Cited by 759 publications

References 29 publications

Topology of the outer-membrane secretin PilQ from Neisseria meningitidis

Topology of the outer-membrane secretin PilQ from Neisseria meningitidis

BfpU, a soluble protein essential for type IV pilus biogenesis in enteropathogenic Escherichia coli

Nanoscale visualization and characterization of Myxococcus xanthus cells with atomic force microscopy

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