scholarly journals Novel mechanisms of type IV pilus regulation in Acinetobacter baylyi

2020 ◽  
Author(s):  
Courtney K. Ellison ◽  
Triana N. Dalia ◽  
Catherine A. Klancher ◽  
Joshua W. Shaevitz ◽  
Zemer Gitai ◽  
...  
Keyword(s):  
Model Organism ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Twitching Motility ◽  
Acinetobacter Baylyi ◽  
Model Species ◽  
Type Iv ◽  
Surface Sensing ◽  
Chemosensory Pathway ◽  
Virulence Protein

AbstractBacteria employ extracellular appendages called type IV pili (T4P) to interact with their environment. T4P are essential for diverse microbial behaviors including DNA uptake, surface sensing, virulence, protein secretion, and twitching motility (1). While T4P have been studied extensively, our understanding of these nanomachines largely comes from work on a few model species. Here, we develop Acinetobacter baylyi as a new model organism to study T4P and uncover several unreported mechanisms of T4P regulation. First, using recently-developed T4P-labeling methods (2, 3), we demonstrate that A. baylyi T4P are synthesized on one side of the cell body along the long axis of the cell, and we uncover that this pattern is dependent on components of a conserved chemosensory pathway. Second, we overturn the current dogma that T4P extension occurs through the action of a single, highly conserved ATP-hydrolyzing motor (ATPase) called PilB by showing that T4P synthesis in A. baylyi is dependent on two partially redundant and phylogenetically distinct motors, PilB and PilB2. Third, we uncover a small protein inhibitor of T4P synthesis that specifically inhibits PilB but not PilB2 activity. Together, these results demonstrate novel mechanisms of T4P regulation, which have broad implications for the unexplored diversity of T4P biology in microbial species.

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

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Courtney K. Ellison ◽  
Triana N. Dalia ◽  
Catherine A. Klancher ◽  
Joshua W. Shaevitz ◽  
Zemer Gitai ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Twitching Motility ◽  
Protein Inhibitor ◽  
Acinetobacter Baylyi ◽  
Type Iv ◽  
Surface Sensing ◽  
Virulence Protein ◽  
Labeling Method

AbstractBacteria 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. By contrast to previous studies of other bacterial species, we find that T4P synthesis in A. baylyi is dependent not only on PilB but also on an additional, phylogenetically distinct motor, TfpB. Furthermore, we identify a protein (CpiA) that inhibits T4P extension by specifically binding and inhibiting PilB but not TfpB. These results expand our understanding of T4P regulation and highlight how inhibitors might be exploited to disrupt T4P synthesis.

scholarly journals The role of core and accessory type IV pilus genes in natural transformation and twitching motility in the bacterium Acinetobacter baylyi

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0182139 ◽  
Author(s):  
Colleen G. Leong ◽  
Rebecca A. Bloomfield ◽  
Caroline A. Boyd ◽  
Amber J. Dornbusch ◽  
Leah Lieber ◽  
...  
Keyword(s):  
Natural Transformation ◽  
Twitching Motility ◽  
Type Iv Pilus ◽  
Acinetobacter Baylyi ◽  
Type Iv

scholarly journals Motility and adhesion through type IV pili in Gram-positive bacteria

2016 ◽  
Vol 44 (6) ◽  
pp. 1659-1666 ◽  
Author(s):  
Kurt H. Piepenbrink ◽  
Eric J. Sundberg
Keyword(s):  
Bacterial Species ◽  
Cellular Adhesion ◽  
Type Iv Pili ◽  
Twitching Motility ◽  
Gram Positive ◽  
Bacterial Surface ◽  
Gram Positive Bacteria ◽  
Type Iv ◽  
Current State ◽  
Highly Hydrophobic

Type IV pili are hair-like bacterial surface appendages that play a role in diverse processes such as cellular adhesion, colonization, twitching motility, biofilm formation, and horizontal gene transfer. These extracellular fibers are composed exclusively or primarily of many copies of one or more pilin proteins, tightly packed in a helix so that the highly hydrophobic amino-terminus of the pilin is buried in the pilus core. Type IV pili have been characterized extensively in Gram-negative bacteria, and recent advances in high-throughput genomic sequencing have revealed that they are also widespread in Gram-positive bacteria. Here, we review the current state of knowledge of type IV pilus systems in Gram-positive bacterial species and discuss them in the broader context of eubacterial type IV pili.

scholarly journals Mucin inhibitsPseudomonas aeruginosabiofilm formation by significantly enhancing twitching motility

2014 ◽  
Vol 60 (3) ◽  
pp. 155-166 ◽  
Author(s):  
Cecily L. Haley ◽  
Cassandra Kruczek ◽  
Uzma Qaisar ◽  
Jane A. Colmer-Hamood ◽  
Abdul N. Hamood
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iv Pili ◽  
Dependent Manner ◽  
Twitching Motility ◽  
Strain Pao1 ◽  
Concentration Dependent Manner ◽  
Dependent Effect ◽  
Type Iv ◽  
Biofilm Development

In Pseudomonas aeruginosa, type IV pili (TFP)-dependent twitching motility is required for development of surface-attached biofilm (SABF), yet excessive twitching motility is detrimental once SABF is established. In this study, we show that mucin significantly enhanced twitching motility and decreased SABF formation in strain PAO1 and other P. aeruginosa strains in a concentration-dependent manner. Mucin also disrupted partially established SABF. Our analyses revealed that mucin increased the amount of surface pilin and enhanced transcription of the pilin structural gene pilA. Mucin failed to enhance twitching motility in P. aeruginosa mutants defective in genes within the pilin biogenesis operons pilGHI/pilJK-chpA-E. Furthermore, mucin did not enhance twitching motility nor reduce biofilm development by chelating iron. We also examined the role of the virulence factor regulator Vfr in the effect of mucin. In the presence or absence of mucin, PAOΔvfr produced a significantly reduced SABF. However, mucin partially complemented the twitching motility defect of PAOΔvfr. These results suggest that mucin interferes with SABF formation at specific concentrations by enhancing TFP synthesis and twitching motility, that this effect, which is iron-independent, requires functional Vfr, and only part of the Vfr-dependent effect of mucin on SABF development occurs through twitching motility.

scholarly journals Two forms of phosphomannomutase in gammaproteobacteria: The overlooked membrane-bound form of AlgC is required for twitching motility ofLysobacter enzymogenes

2019 ◽  
Author(s):  
Guoliang Qian ◽  
Shifang Fei ◽  
Michael Y. Galperin
Keyword(s):  
Fungal Pathogens ◽  
Xanthomonas Campestris ◽  
Azotobacter Vinelandii ◽  
Gene Clusters ◽  
Type Iv Pili ◽  
Twitching Motility ◽  
Entire Genome ◽  
Type Iv ◽  
Promising Tool ◽  
Membrane Bound

ABSTRACTLysobacter enzymogenes, a member ofXanthomonadaceae, is a promising tool to control crop-destroying fungal pathogens. One of its key antifungal virulence factors is the type IV pili that are required for twitching motility. Transposon mutagenesis ofL.enzymogenesrevealed that production of type IV pili required the presence of theLe2152gene, which encodes an AlgC-type phosphomannomutase/phosphoglucomutase (PMM). However, in addition to the cytoplasmic PMM domain, the Le2152 gene product contains a ca. 200-aa N-terminal periplasmic domain that is anchored in the membrane by two transmembrane segments and belongs to the dCache superfamily of periplasmic sensor domains. Sequence analysis identified similar membrane-anchored PMMs, encoded in conservedcoaBC-dut-algCgene clusters, in a variety of gammaproteobacteria, either as the sole PMM gene in the entire genome or in addition to the gene encoding the stand-alone enzymatic domain. Previously overlooked N-terminal periplasmic sensor domains were detected in the well-characterized PMMs ofPseudomonas aeruginosaandXanthomonas campestris, albeit not in the enzymes fromPseudomonas fluorescens, Pseudomonas putidaorAzotobacter vinelandii. It appears that after the initial cloning of the enzymatically active soluble part ofP.aeruginosaAlgC in 1991, all subsequent studies utilized N-terminally truncated open reading frames. The N-terminal dCache sensor domain of AlgC is predicted to modulate the PMM activity of the cytoplasmic domain in response to as yet unidentified environmental signal(s). AlgC-like membrane-bound PMMs appear to comprise yet another environmental signaling system that regulates production of type IV pili and potentially other systems in certain gammaproteobacteria.

scholarly journals EpicPCR-Directed Cultivation of a Candidatus Saccharibacteria Symbiont Reveals a Type IV Pili-dependent Epibiotic Lifestyle

2021 ◽  
Author(s):  
Bingliang Xie ◽  
Jian Wang ◽  
Yong Nie ◽  
Dongwei Chen ◽  
Beiyu Hu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Microscopic Investigation ◽  
Type Iv Pili ◽  
Genomic Profiling ◽  
Twitching Motility ◽  
Isolation Method ◽  
Type Iv ◽  
Limited Culture

Candidate phyla radiations (CPR), accounting for a major microbial supergroup with remarkably small genomes and reduced sizes, are widely distributed yet mostly uncultured. Limited culture and its obligate reliance upon other bacteria hindered investigation of their lifestyles. In this work we isolated a CPR bacterium, TM7i, with its host Leucobacter aridocollis J1, by combination of Emulsion, Paired Isolation and Concatenation PCR (epicPCR) detection and filtrate co-culture. Genomic profiling of TM7 genomes and microscopic investigation of TM7i-J1 symbiosis suggest the conservation of type IV pili and a pili-dependent lifestyle of TM7. Further, we observed twitching motility of TM7i mediated by pili and its role played in the interaction with its host. Our results shed a light on the lifestyle about this enigmatic bacterial radiation, which may also be adopted by other CPR organisms. The epicPCR-directed isolation method underlines high efficiency of CPR bacteria isolation and thus may be used in other symbiotic or epibiotic microorganisms.

scholarly journals Type IV competence pili in Streptococcus pneumoniae are highly dynamic structures that retract to promote DNA uptake

2021 ◽  
Author(s):  
Trinh Lam ◽  
Courtney K. Ellison ◽  
Ankur B. Dalia ◽  
David T. Eddington ◽  
Donald A. Morrison
Keyword(s):  
Cell Surface ◽  
Active Role ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Gram Positive ◽  
Dynamic Activity ◽  
Positive Type ◽  
Type Iv ◽  
Labeling Approach ◽  
Dynamic Structures

SUMMARYThe competence pili of transformable Gram-positive species form a subset of the diverse and widespread class of extracellular filamentous organelles known as type IV pili (T4P). In Gram-negative bacteria, T4P 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 T4P in Gram-positive species exhibit this same dynamic activity, and their mechanism of action for DNA uptake remains unclear. They are hypothesized to either (1) passively form transient cavities in the cell wall to facilitate DNA passage, (2) act as static adhesins to enrich DNA near the cell surface for subsequent uptake by membrane-embedded transporters, or (3) play an active role in translocating bound DNA via their dynamic activity. Here, using a recently described pilus labeling approach, we demonstrate that pneumococcal competence pili are highly dynamic structures that rapidly extend and retract from the cell surface. By labeling ComGC with bulky adducts, we further demonstrate that pilus retraction is essential for natural transformation. Together, our results indicate that Gram-positive type IV competence pili are dynamic and retractile structures that play an active role in DNA uptake.Short summaryCompetent pneumococci kill non-competent cells on contact. Retractable DNA-binding fibers in the class of type IV pili may provide a key tool for retrieving DNA segments from cell wreckage for internalization and recombination.

scholarly journals Receptor recognition by meningococcal type IV pili relies on a specific complex N-glycan

2020 ◽  
Vol 117 (5) ◽  
pp. 2606-2612 ◽  
Author(s):  
Loic Le Guennec ◽  
Zoé Virion ◽  
Haniaa Bouzinba-Ségard ◽  
Catherine Robbe-Masselot ◽  
Renaud Léonard ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Model Organism ◽  
Structural Diversity ◽  
Type Iv Pili ◽  
Type Iv ◽  
Receptor Recognition ◽  
Specific Complex ◽  
Species Specific ◽  
Adhesive Factor ◽  
Antibacterial Target

Bacterial infections are frequently based on the binding of lectin-like adhesins to specific glycan determinants exposed on host cell receptors. These interactions confer species-specific recognition and tropism for particular host tissues and represent attractive antibacterial targets. However, the wide structural diversity of carbohydrates hampers the characterization of specific glycan determinants. Here, we characterized the receptor recognition of type IV pili (Tfp), a key adhesive factor present in numerous bacterial pathogens, using Neisseria meningitidis as a model organism. We found that meningococcal Tfp specifically recognize a triantennary sialylated poly-N-acetyllactosamine–containing N-glycan exposed on the human receptor CD147/Basigin, while fucosylated derivatives of this N-glycan impaired bacterial adhesion. Corroborating the inhibitory role of fucosylation on receptor recognition, adhesion of the meningococcus on nonhuman cells expressing human CD147 required prior defucosylation. These findings reveal the molecular basis of the selective receptor recognition by meningococcal Tfp and thereby, identify a potential antibacterial target.

scholarly journals Type IV Pili Are Required for Virulence, Twitching Motility, and Biofilm Formation of Acidovorax avenae subsp. citrulli

2009 ◽  
Vol 22 (8) ◽  
pp. 909-920 ◽  
Author(s):  
Ofir Bahar ◽  
Tal Goffer ◽  
Saul Burdman
Keyword(s):  
Biofilm Formation ◽  
Host Plants ◽  
Seed Transmission ◽  
Type Iv Pili ◽  
Twitching Motility ◽  
Wild Type ◽  
Type Iv ◽  
Group I ◽  
Tn5 Mutant

Acidovorax avenae subsp. citrulli is the causal agent of bacterial fruit blotch (BFB), a threatening disease of watermelon, melon, and other cucurbits. Despite the economic importance of BFB, relatively little is known about basic aspects of the pathogen's biology and the molecular basis of its interaction with host plants. To identify A. avenae subsp. citrulli genes associated with pathogenicity, we generated a transposon (Tn5) mutant library on the background of strain M6, a group I strain of A. avenae subsp. citrulli, and screened it for reduced virulence by seed-transmission assays with melon. Here, we report the identification of a Tn5 mutant with reduced virulence that is impaired in pilM, which encodes a protein involved in assembly of type IV pili (TFP). Further characterization of this mutant revealed that A. avenae subsp. citrulli requires TFP for twitching motility and wild-type levels of biofilm formation. Significant reductions in virulence and biofilm formation as well as abolishment of twitching were also observed in insertional mutants affected in other TFP genes. We also provide the first evidence that group I strains of A. avenae subsp. citrulli can colonize and move through host xylem vessels.

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