236 results match your criteria pilus retraction

The PilB-PilZ-FimX regulatory complex of the Type IV pilus from Xanthomonas citri.

PLoS Pathog 2021 Aug 16;17(8):e1009808. Epub 2021 Aug 16.

Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.

Type IV pili (T4P) are thin and flexible filaments found on the surface of a wide range of Gram-negative bacteria that undergo cycles of extension and retraction and participate in a variety of important functions related to lifestyle, defense and pathogenesis. During pilus extensions, the PilB ATPase energizes the polymerization of pilin monomers from the inner membrane. In Xanthomonas citri, two cytosolic proteins, PilZ and the c-di-GMP receptor FimX, are involved in the regulation of T4P biogenesis through interactions with PilB. Read More

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Acinetobacter baylyi regulates type IV pilus synthesis by employing two extension motors and a motor protein inhibitor.

Nat Commun 2021 06 18;12(1):3744. Epub 2021 Jun 18.

Department of Biology, Indiana University, Bloomington, IN, USA.

Bacteria use extracellular appendages called type IV pili (T4P) for diverse behaviors including DNA uptake, surface sensing, virulence, protein secretion, and twitching motility. Dynamic extension and retraction of T4P is essential for their function, and T4P extension is thought to occur through the action of a single, highly conserved motor, PilB. Here, we develop Acinetobacter baylyi as a model to study T4P by employing a recently developed pilus labeling method. Read More

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Lactate-Induced Dispersal of Microcolonies Is Mediated by Changes in Cell Density and Pilus Retraction and Is Influenced by Temperature Change.

Infect Immun 2021 Sep 14;89(10):e0029621. Epub 2021 Jun 14.

Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm Universitygrid.10548.38, Stockholm, Sweden.

Neisseria meningitidis is the etiologic agent of meningococcal meningitis and sepsis. Initial colonization of meningococci in the upper respiratory tract epithelium is crucial for disease development. The colonization occurs in several steps and expression of type IV pili (Tfp) is essential for both attachment and microcolony formation of encapsulated bacteria. Read More

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September 2021

Fresh Extension of Vibrio cholerae Competence Type IV Pili Predisposes Them for Motor-Independent Retraction.

Appl Environ Microbiol 2021 06 25;87(14):e0047821. Epub 2021 Jun 25.

Department of Biology, Indiana University, Bloomington, Indiana, USA.

Bacteria utilize dynamic appendages, called type IV pili (T4P), to interact with their environment and mediate a wide variety of functions. Pilus extension is mediated by an extension ATPase motor, commonly called PilB, in all T4P. Pilus retraction, however, can occur with the aid of an ATPase motor or in the absence of a retraction motor. Read More

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AFM force-clamp spectroscopy captures the nanomechanics of the Tad pilus retraction.

Nanoscale Horiz 2021 06;6(6):489-496

Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte, L7.07.07, Louvain-la-Neuve B-1348, Belgium.

Motorization of bacterial pili is key to generate traction forces to achieve cellular function. The Tad (or Type IVc) pilus from Caulobacter crescentus is a widespread motorized nanomachine crucial for bacterial survival, evolution and virulence. An unusual bifunctional ATPase motor drives Tad pilus retraction, which helps the bacteria to land on target surfaces. Read More

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Competence pili in Streptococcus pneumoniae are highly dynamic structures that retract to promote DNA uptake.

Mol Microbiol 2021 08 16;116(2):381-396. Epub 2021 Apr 16.

Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA.

The competence pili of transformable Gram-positive species are phylogenetically related to the diverse and widespread class of extracellular filamentous organelles known as type IV pili. In Gram-negative bacteria, type IV pili act through dynamic cycles of extension and retraction to carry out diverse activities including attachment, motility, protein secretion, and DNA uptake. It remains unclear whether competence pili in Gram-positive species exhibit similar dynamic activity, and their mechanism of action for DNA uptake remains unclear. Read More

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Competitive binding of independent extension and retraction motors explains the quantitative dynamics of type IV pili.

Proc Natl Acad Sci U S A 2021 02;118(8)

Department of Molecular Biology, Princeton University, Princeton, NJ 08540;

Type IV pili (TFP) function through cycles of extension and retraction. The coordination of these cycles remains mysterious due to a lack of quantitative measurements of multiple features of TFP dynamics. Here, we fluorescently label TFP in the pathogen and track full extension and retraction cycles of individual filaments. Read More

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February 2021

Type IV pilus retraction enables sustained bacteremia and plays a key role in the outcome of meningococcal sepsis in a humanized mouse model.

PLoS Pathog 2021 02 16;17(2):e1009299. Epub 2021 Feb 16.

Université de Paris, Faculté de Médecine, Paris, France.

Neisseria meningitidis (the meningococcus) remains a major cause of bacterial meningitis and fatal sepsis. This commensal bacterium of the human nasopharynx can cause invasive diseases when it leaves its niche and reaches the bloodstream. Blood-borne meningococci have the ability to adhere to human endothelial cells and rapidly colonize microvessels. Read More

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February 2021

The structure and mechanism of the bacterial type II secretion system.

Mol Microbiol 2021 03 29;115(3):412-424. Epub 2020 Dec 29.

Department of Infectious Disease, Imperial College, London, UK.

The type II secretion system (T2SS) is a multi-protein complex used by many bacteria to move substrates across their cell membrane. Substrates released into the environment serve as local and long-range effectors that promote nutrient acquisition, biofilm formation, and pathogenicity. In both animals and plants, the T2SS is increasingly recognized as a key driver of virulence. Read More

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The Role of the Cyanobacterial Type IV Pilus Machinery in Finding and Maintaining a Favourable Environment.

Life (Basel) 2020 Oct 23;10(11). Epub 2020 Oct 23.

Institute of Biology III, University of Freiburg, Schänzlestr. 1, 79104 Freiburg; Germany.

Type IV pili (T4P) are proteinaceous filaments found on the cell surface of many prokaryotic organisms and convey twitching motility through their extension/retraction cycles, moving cells across surfaces. In cyanobacteria, twitching motility is the sole mode of motility properly characterised to date and is the means by which cells perform phototaxis, the movement towards and away from directional light sources. The wavelength and intensity of the light source determine the direction of movement and, sometimes in concert with nutrient conditions, act as signals for some cyanobacteria to form mucoid multicellular assemblages. Read More

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October 2020

Discovery of a New Neisseria gonorrhoeae Type IV Pilus Assembly Factor, TfpC.

mBio 2020 10 27;11(5). Epub 2020 Oct 27.

Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA

relies on type IV pili (T4p) to promote colonization of their human host and to cause the sexually transmitted infection gonorrhea. This organelle cycles through a process of extension and retraction back into the bacterial cell. Through a genetic screen, we identified the NGO0783 locus of strain FA1090 as containing a gene encoding a protein required to stabilize the type IV pilus in its extended, nonretracted conformation. Read More

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October 2020

PilY1 and minor pilins form a complex priming the type IVa pilus in Myxococcus xanthus.

Nat Commun 2020 10 7;11(1):5054. Epub 2020 Oct 7.

Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.

Type IVa pili are ubiquitous and versatile bacterial cell surface filaments that undergo cycles of extension, adhesion and retraction powered by the cell-envelope spanning type IVa pilus machine (T4aPM). The overall architecture of the T4aPM and the location of 10 conserved core proteins within this architecture have been elucidated. Here, using genetics, cell biology, proteomics and cryo-electron tomography, we demonstrate that the PilY1 protein and four minor pilins, which are widely conserved in T4aP systems, are essential for pilus extension in Myxococcus xanthus and form a complex that is an integral part of the T4aPM. Read More

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October 2020

ssRNA phage penetration triggers detachment of the F-pilus.

Proc Natl Acad Sci U S A 2020 10 28;117(41):25751-25758. Epub 2020 Sep 28.

Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843;

Although the F-specific ssRNA phage MS2 has long had paradigm status, little is known about penetration of the genomic RNA (gRNA) into the cell. The phage initially binds to the F-pilus using its maturation protein (Mat), and then the Mat-bound gRNA is released from the viral capsid and somehow crosses the bacterial envelope into the cytoplasm. To address the mechanics of this process, we fluorescently labeled the ssRNA phage MS2 to track F-pilus dynamics during infection. Read More

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October 2020

The small GTPase MglA together with the TPR domain protein SgmX stimulates type IV pili formation in .

Proc Natl Acad Sci U S A 2020 09 8;117(38):23859-23868. Epub 2020 Sep 8.

Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany

Bacteria can move across surfaces using type IV pili (T4P), which undergo cycles of extension, adhesion, and retraction. The T4P localization pattern varies between species; however, the underlying mechanisms are largely unknown. In the rod-shaped cells, T4P localize at the leading cell pole. Read More

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September 2020

Cryo-EM reveals infection steps of single-stranded RNA bacteriophages.

Prog Biophys Mol Biol 2021 03 22;160:79-86. Epub 2020 Aug 22.

Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA. Electronic address:

Single-stranded RNA bacteriophages (ssRNA phages) are small spherical RNA viruses that infect bacteria with retractile pili. The single positive-sense genomic RNA of ssRNA phages, which is protected by a capsid shell, is delivered into the host via the retraction of the host pili. Structures involved in ssRNA phage infection cycle are essential for understanding the underlying mechanisms that can be used to engineer them for therapeutic applications. Read More

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Surface sensing stimulates cellular differentiation in .

Proc Natl Acad Sci U S A 2020 07 13;117(30):17984-17991. Epub 2020 Jul 13.

Department of Biology, Indiana University, Bloomington, IN 47405;

Cellular differentiation is a fundamental strategy used by cells to generate specialized functions at specific stages of development. The bacterium employs a specialized dimorphic life cycle consisting of two differentiated cell types. How environmental cues, including mechanical inputs such as contact with a surface, regulate this cell cycle remain unclear. Read More

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Modulation of bacterial multicellularity via spatio-specific polysaccharide secretion.

PLoS Biol 2020 06 9;18(6):e3000728. Epub 2020 Jun 9.

Laboratoire de Chimie Bactérienne, CNRS-Université Aix-Marseille UMR, Institut de Microbiologie de la Méditerranée, Marseille, France.

The development of multicellularity is a key evolutionary transition allowing for differentiation of physiological functions across a cell population that confers survival benefits; among unicellular bacteria, this can lead to complex developmental behaviors and the formation of higher-order community structures. Herein, we demonstrate that in the social δ-proteobacterium Myxococcus xanthus, the secretion of a novel biosurfactant polysaccharide (BPS) is spatially modulated within communities, mediating swarm migration as well as the formation of multicellular swarm biofilms and fruiting bodies. BPS is a type IV pilus (T4P)-inhibited acidic polymer built of randomly acetylated β-linked tetrasaccharide repeats. Read More

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ChpC controls twitching motility-mediated expansion of biofilms in response to serum albumin, mucin and oligopeptides.

Microbiology (Reading) 2020 07;166(7):669-678

Microbes in the Food Chain Programme, Quadram Institute Bioscience, Norwich Research Park, NR4 7UQ and School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich, UK.

Twitching motility-mediated biofilm expansion occurs via coordinated, multi-cellular collective behaviour to allow bacteria to actively expand across surfaces. Type-IV pili (T4P) are cell-associated virulence factors which mediate twitching motility via rounds of extension, surface attachment and retraction. The Chp chemosensory system is thought to respond to environmental signals to regulate the biogenesis, assembly and twitching motility function of T4P. Read More

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The type IV pilin PilA couples surface attachment and cell-cycle initiation in .

Proc Natl Acad Sci U S A 2020 04 15;117(17):9546-9553. Epub 2020 Apr 15.

Institute of Molecular Systems Biology, Department of Biology, Eidgenössische Technische HochschuleZürich, Zürich 8093, Switzerland

Understanding how bacteria colonize surfaces and regulate cell-cycle progression in response to cellular adhesion is of fundamental importance. Here, we use transposon sequencing in conjunction with fluorescence resonance energy transfer (FRET) microscopy to uncover the molecular mechanism for how surface sensing drives cell-cycle initiation in We identify the type IV pilin protein PilA as the primary signaling input that couples surface contact to cell-cycle initiation via the second messenger cyclic di-GMP (c-di-GMP). Upon retraction of pili filaments, the monomeric pilin reservoir in the inner membrane is sensed by the 17-amino acid transmembrane helix of PilA to activate the PleC-PleD two-component signaling system, increase cellular c-di-GMP levels, and signal the onset of the cell cycle. Read More

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c-di-GMP modulates type IV MSHA pilus retraction and surface attachment in Vibrio cholerae.

Nat Commun 2020 03 25;11(1):1549. Epub 2020 Mar 25.

Department of Microbiology and Environmental Toxicology, University of California - Santa Cruz, 1156 High St., BioMed 245, Santa Cruz, CA, 95064, USA.

Biofilm formation by Vibrio cholerae facilitates environmental persistence, and hyperinfectivity within the host. Biofilm formation is regulated by 3',5'-cyclic diguanylate (c-di-GMP) and requires production of the type IV mannose-sensitive hemagglutinin (MSHA) pilus. Here, we show that the MSHA pilus is a dynamic extendable and retractable system, and its activity is directly controlled by c-di-GMP. Read More

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Conditional requirement of SglT for type IV pili function and S-motility in .

Microbiology (Reading) 2020 04 7;166(4):349-358. Epub 2020 Feb 7.

Department of Molecular Biology, University of Wyoming, 1000 E University Avenue, Laramie, WY, 82071, USA.

Myxobacteria exhibit complex social behaviors such as predation, outer membrane exchange and fruiting body formation. These behaviors depend on coordinated movements of cells on solid surfaces that involve social (S) motility. S-motility is powered by extension-retraction cycles of type 4 pili (Tfp) and exopolysaccharides (EPS) that provide a matrix for group cellular movement. Read More

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A bifunctional ATPase drives tad pilus extension and retraction.

Sci Adv 2019 12 18;5(12):eaay2591. Epub 2019 Dec 18.

Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47405, USA.

A widespread class of prokaryotic motors powered by secretion motor adenosine triphosphatases (ATPases) drives the dynamic extension and retraction of extracellular fibers, such as type IV pili (T4P). Among these, the tight adherence (tad) pili are critical for surface sensing and biofilm formation. As for most other motors belonging to this class, how tad pili retract despite lacking a dedicated retraction motor ATPase has remained a mystery. Read More

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December 2019

PilT and PilU are homohexameric ATPases that coordinate to retract type IVa pili.

PLoS Genet 2019 10 18;15(10):e1008448. Epub 2019 Oct 18.

Department of Biology, Indiana University, Bloomington, Indiana, United States of America.

Bacterial type IV pili are critical for diverse biological processes including horizontal gene transfer, surface sensing, biofilm formation, adherence, motility, and virulence. These dynamic appendages extend and retract from the cell surface. In many type IVa pilus systems, extension occurs through the action of an extension ATPase, often called PilB, while optimal retraction requires the action of a retraction ATPase, PilT. Read More

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October 2019

The type IV pilus protein PilU functions as a PilT-dependent retraction ATPase.

PLoS Genet 2019 09 16;15(9):e1008393. Epub 2019 Sep 16.

Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH, Lausanne, Switzerland.

Type IV pili are dynamic cell surface appendages found throughout the bacteria. The ability of these structures to undergo repetitive cycles of extension and retraction underpins their crucial roles in adhesion, motility and natural competence for transformation. In the best-studied systems a dedicated retraction ATPase PilT powers pilus retraction. Read More

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September 2019

Surface association sensitizes Pseudomonas aeruginosa to quorum sensing.

Nat Commun 2019 09 11;10(1):4118. Epub 2019 Sep 11.

Department of Molecular Biology, Princeton University, Princeton, NJ, 08540, USA.

In the pathogen Pseudomonas aeruginosa, LasR is a quorum sensing (QS) master regulator that senses the concentration of secreted autoinducers as a proxy for bacterial cell density. Counterintuitively, previous studies showed that saturating amounts of the LasR ligand, 3OC12-HSL, fail to induce the full LasR regulon in low-density liquid cultures. Here we demonstrate that surface association, which is necessary for many of the same group behaviors as QS, promotes stronger QS responses. Read More

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September 2019

The minor pilin TcpB mediates uptake of the cholera toxin phage CTXφ.

J Biol Chem 2019 10 30;294(43):15698-15710. Epub 2019 Aug 30.

Molecular Biology and Biochemistry Department, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada

Virulent strains of the bacterial pathogen cause the diarrheal disease cholera by releasing cholera toxin into the small intestine. acquired its cholera toxin genes by lysogenic infection with the filamentous bacteriophage CTXφ. CTXφ uses its minor coat protein pIII, located in multiple copies at the phage tip, to bind to the toxin-coregulated pilus (TCP). Read More

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October 2019

Mechanisms of DNA Uptake by Naturally Competent Bacteria.

Annu Rev Genet 2019 12 21;53:217-237. Epub 2019 Aug 21.

Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.

Transformation is a widespread mechanism of horizontal gene transfer in bacteria. DNA uptake to the periplasmic compartment requires a DNA-uptake pilus and the DNA-binding protein ComEA. In the gram-negative bacteria, DNA is first pulled toward the outer membrane by retraction of the pilus and then taken up by binding to periplasmic ComEA, acting as a Brownian ratchet to prevent backward diffusion. Read More

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December 2019

Structural basis for the adsorption of a single-stranded RNA bacteriophage.

Nat Commun 2019 07 16;10(1):3130. Epub 2019 Jul 16.

Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA.

Single-stranded RNA bacteriophages (ssRNA phages) infect Gram-negative bacteria via a single maturation protein (Mat), which attaches to a retractile pilus of the host. Here we present structures of the ssRNA phage MS2 in complex with the Escherichia coli F-pilus, showing a network of hydrophobic and electrostatic interactions at the Mat-pilus interface. Moreover, binding of the pilus induces slight orientational variations of the Mat relative to the rest of the phage capsid, priming the Mat-connected genomic RNA (gRNA) for its release from the virions. Read More

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Factors Controlling Floc Formation and Structure in the Cyanobacterium sp. Strain PCC 6803.

J Bacteriol 2019 10 6;201(19). Epub 2019 Sep 6.

School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom

Motile strains of the unicellular cyanobacterium sp. strain PCC 6803 readily aggregate into flocs, or floating multicellular assemblages, when grown in liquid culture. As described here, we used confocal imaging to probe the structure of these flocs, and we developed a quantitative assay for floc formation based on fluorescence imaging of 6-well plates. Read More

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October 2019

Tad Pili Play a Dynamic Role in Caulobacter crescentus Surface Colonization.

mBio 2019 06 18;10(3). Epub 2019 Jun 18.

Biozentrum, University of Basel, Basel, Switzerland

Bacterial surface attachment is mediated by filamentous appendages called pili. Here, we describe the role of Tad pili during surface colonization of Using an optical trap and microfluidic controlled flow conditions to mimic natural environments, we demonstrated that Tad pili undergo repeated dynamic cycles of extension and retraction. Within seconds after establishing surface contact, pilus retraction reorients cells into an upright position, promoting walking-like movements against the medium flow. Read More

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