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 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 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 Type IV Pilus Biogenesis, Twitching Motility, and DNA Uptake in Thermus thermophilus: Discrete Roles of Antagonistic ATPases PilF, PilT1, and PilT2

2013 ◽  
Vol 80 (2) ◽  
pp. 644-652 ◽  
Author(s):  
Ralf Salzer ◽  
Friederike Joos ◽  
Beate Averhoff
Keyword(s):  
Natural Transformation ◽  
Thermophilic Bacteria ◽  
Bacterial Species ◽  
Thermus Thermophilus ◽  
Dna Uptake ◽  
Twitching Motility ◽  
Type Iv Pilus ◽  
Content Type ◽  
Ecological Diversification ◽  
Type Iv

ABSTRACTNatural transformation has a large impact on lateral gene flow and has contributed significantly to the ecological diversification and adaptation of bacterial species.Thermus thermophilusHB27 has emerged as the leading model organism for studies of DNA transporters in thermophilic bacteria. Recently, we identified a zinc-binding polymerization nucleoside triphosphatase (NTPase), PilF, which is essential for the transport of DNA through the outer membrane. Here, we present genetic evidence that PilF is also essential for the biogenesis of pili. One of the most challenging questions was whetherT. thermophilushas any depolymerization NTPase acting as a counterplayer of PilF. We identified two depolymerization NTPases, PilT1 (TTC1621) and PilT2 (TTC1415), both of which are required for type IV pilus (T4P)-mediated twitching motility and adhesion but dispensable for natural transformation. This suggests that T4P dynamics are not required for natural transformation. The latter finding is consistent with our suggestion that inT. thermophilus, T4P and natural transformation are linked but distinct systems.

scholarly journals Type IV pili share a conserved mechanism of motor-independent retraction that is an inherent property of the pilus filament

2021 ◽  
Author(s):  
Jennifer L. Chlebek ◽  
Lisa Craig ◽  
Ankur B. Dalia
Keyword(s):  
Bacterial Pathogens ◽  
Bacterial Species ◽  
Type Iv Pili ◽  
Secretion Systems ◽  
Acinetobacter Baylyi ◽  
Dynamic Activity ◽  
Dynamic Surface ◽  
Inherent Property ◽  
Type Iv ◽  
Pilin Gene

ABSTRACTType IV pili (T4P) are dynamic surface appendages that promote virulence, biofilm formation, horizontal gene transfer, and motility in diverse bacterial species. Pilus dynamic activity is best characterized in T4P that use distinct ATPase motors for pilus extension and retraction. Many T4P systems, however, lack a dedicated retraction motor and the mechanism underlying this motor-independent retraction remains a mystery. Using the Vibrio cholerae competence pilus as a model system, we identify mutations in the major pilin gene that enhance motor-independent retraction. These mutants produced less stable pili, likely due to diminished pilin-pilin interactions within the filament. One mutation adds a bulky residue to α1C, a universally conserved feature of type IV pilins. We found that inserting a bulky residue into α1C of the retraction motor-dependent Acinetobacter baylyi com-petence T4P is sufficient to induce motor-independent retraction. Conversely, removing bulky residues from α1C of the retraction motor-independent V. cholerae toxin-co-regulated T4P stabilizes the filament and prevents retraction. Furthermore, alignment of pilins from the broader type IV filament (T4F) family indicated that retraction motor-independent T4P, Com pili, and type II secretion systems generally encode larger residues within α1C oriented toward the pilus core compared to retraction motor-dependent T4P. Together, our data demonstrate that motor-independent retraction relies on the inherent instability of the pilus filament that may be conserved in diverse T4Fs. This provides the first evidence for a long-standing, yet untested, model in which pili retract in the absence of a motor by spontaneous de-polymerization.SIGNIFICANCEExtracellular pilus filaments are critical for the virulence and persistence of many bacterial pathogens. A crucial property of these filaments is their ability to dynamically extend and retract from the bacterial surface. A detailed mechanistic understanding of pilus retraction, however, remains lacking in many systems. Here, we reveal that pilus retraction is an inherent property of the pilus filament. These observations are broadly relevant to diverse pilus systems, including those in many bacterial pathogens, and may help inform novel therapeutic strategies that aim to target pilus dynamic activity.

Motor-independent retraction of type IV pili is governed by an inherent property of the pilus filament

2021 ◽  
Vol 118 (47) ◽  
pp. e2102780118
Author(s):  
Jennifer L. Chlebek ◽  
Rémi Denise ◽  
Lisa Craig ◽  
Ankur B. Dalia
Keyword(s):  
Biofilm Formation ◽  
Bacterial Species ◽  
Type Iv Pili ◽  
Type Ii Secretion ◽  
Secretion Systems ◽  
Acinetobacter Baylyi ◽  
Dynamic Activity ◽  
Dynamic Surface ◽  
Type Iv ◽  
Pilin Gene

Type IV pili (T4P) are dynamic surface appendages that promote virulence, biofilm formation, horizontal gene transfer, and motility in diverse bacterial species. Pilus dynamic activity is best characterized in T4P that use distinct ATPase motors for pilus extension and retraction. Many T4P systems, however, lack a dedicated retraction motor, and the mechanism underlying this motor-independent retraction remains a mystery. Using the Vibrio cholerae competence pilus as a model system, we identify mutations in the major pilin gene that enhance motor-independent retraction. These mutants likely diminish pilin–pilin interactions within the filament to produce less-stable pili. One mutation adds a bulky residue to α1C, a universally conserved feature of T4P. We found that inserting a bulky residue into α1C of the retraction motor–dependent Acinetobacter baylyi competence T4P enhances motor-independent retraction. Conversely, removing bulky residues from α1C of the retraction motor–independent, V. cholerae toxin-coregulated T4P stabilizes the filament and diminishes pilus retraction. Furthermore, alignment of pilins from the broader type IV filament (T4F) family indicated that retraction motor–independent T4P, gram-positive Com pili, and type II secretion systems generally encode larger residues within α1C oriented toward the pilus core compared to retraction motor–dependent T4P. Together, our data demonstrate that motor-independent retraction relies, in part, on the inherent instability of the pilus filament, which may be a conserved feature of diverse T4Fs. This provides evidence for a long-standing yet previously untested model in which pili retract in the absence of a motor by spontaneous depolymerization.

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 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.

Analysis of type IV pilus and its associated motility in Myxococcus xanthus using an antibody reactive with native pilin and pili

Microbiology ◽  
2005 ◽  
Vol 151 (2) ◽  
pp. 353-360 ◽  
Author(s):  
Yinuo Li ◽  
Renate Lux ◽  
Andrew E. Pelling ◽  
James K. Gimzewski ◽  
Wenyuan Shi
Keyword(s):  
Amino Acids ◽  
Current Model ◽  
Bacterial Species ◽  
Myxococcus Xanthus ◽  
Type Iv Pili ◽  
Gliding Motility ◽  
Soluble Form ◽  
Truncated Form ◽  
Type Iv ◽  
Oligomerization Domain

Myxococcus xanthus possesses a social gliding motility that requires type IV pili (TFP). According to the current model, M. xanthus pili attach to an external substrate and retract, pulling the cell body forward along their long axis. By analogy with the situation in other bacteria employing TFP-dependent motility, M. xanthus pili have been assumed to be composed of pilin (PilA) subunits, but this has not previously been confirmed. The first 28 amino acids of the M. xanthus PilA protein share extensive homology with the N-terminal oligomerization domain of pilins in other bacterial species. To facilitate purification, the authors engineered a truncated form of M. xanthus PilA lacking the first 28 amino acids and purified this protein in soluble form. Polyclonal antibody generated against this protein was reactive with native pilin and pili. Using this antibody, it was confirmed that TFP of M. xanthus are indeed composed of PilA, and that TFP are located unipolarly and required for social gliding motility via retraction. Using tethering as well as motility assays, details of pili function in M. xanthus social motility were further examined.

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.

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