Bacterial twitching motility is coordinated by a two-dimensional tug-of-war with directional memory

Marathe, Rahul; Meel, Claudia; Schmidt, Nikolaus; Dewenter, Lena; Kurre, Rainer; Greune, Lilo; Schmidt, M. Alexander; Müller, Melanie J. I.; Lipowsky, Reinhard; Maier, Berenike; Klumpp, Stefan

doi:10.1038/ncomms4759

Cited by 93 publications

(151 citation statements)

References 48 publications

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“…This finding was more notable in the magnified view (Fig. 5E, Inset), proving that the twitching motility was activated randomly with an apparent diffusion coefficient of 1.2 μm 2 /s, which is good agreement with the scaling behavior of the motility in other bacteria (26,27). The start point of the parabolic line indicates the phase transition to directed twitching motility as a result of the negative phototaxis.…”

Section: Resultssupporting

confidence: 77%

Asymmetric distribution of type IV pili triggered by directional light in unicellular cyanobacteria

Nakane

Nishizaka

2017

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

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The type IV pili (T4P) system is a supermolecular machine observed in prokaryotes. Cells repeat the cycle of T4P extension, surface attachment, and retraction to drive twitching motility. Although the properties of T4P as a motor have been scrutinized with biophysics techniques, the mechanism of regulation remains unclear. Here we provided the framework of the T4P dynamics at the single-cell level in Synechocystis sp. PCC6803, which can recognize light direction. We demonstrated that the dynamics was detected by fluorescent beads under an optical microscope and controlled by blue light that induces negative phototaxis; extension and retraction of T4P was activated at the forward side of lateral illumination to move away from the light source. Additionally, we directly visualized each pilus by fluorescent labeling, allowing us to quantify their asymmetric distribution. Finally, quantitative analyses of cell tracking indicated that T4P was generated uniformly within 0.2 min after blue-light exposure, and within the next 1 min the activation became asymmetric along the light axis to achieve directional cell motility; this process was mediated by the photo-sensing protein, PixD. This sequential process provides clues toward a general regulation mechanism of T4P system, which might be essentially common between archaella and other secretion apparatuses.Synechocystis sp. PCC6803 | twitching motility | phototaxis | signal transduction | fluorescence T ype IV pili (T4P) are fascinating supermolecular machines that drive twitching motility, protein secretion, and DNA uptake in prokaryotes (1). Twitching motility is now widely accepted as a form of bacterial translocation involving repetition of the cycle of extension and retraction of the pili (2, 3) (Fig. 1A), which is powered by assembly and disassembly ATPase at the base of helical pilus fibers (4). The mechanical response of a single pilus has been scrutinized in great detail using biophysical approaches such as optical tweezers methodology in Neisseria gonorrheae (3, 5-7), although the dynamic properties resulting from the response to various environmental signals remain less understood than those of bacterial flagella. T4P is also evolutionarily and structurally related to flagella in archaea, which have recently been designated archaella (8-11). Although newly developed techniques enable us to examine the dynamic properties of the machinery, little is known about the regulation mechanism of T4P because tens of components cooperate to orchestrate the dynamics of both the archaella and T4P system. Such complexity hampers the design of an experimental setup with quantitative and reproducible evaluations.To address how the T4P system is activated or repressed by environmental signals over a short timescale, we here used Synechocystis sp. PCC6803, a model cyanobacteria (12)(13)(14). This species exhibits T4P-dependent twitching motility on surfaces such as soft-agar plates at speeds of a few micrometers per minute, and the cell motility direction is regulated both posi...

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Section: Resultssupporting

confidence: 77%

Asymmetric distribution of type IV pili triggered by directional light in unicellular cyanobacteria

Nakane

Nishizaka

2017

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

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“…The speed of WT T4P retraction was v(8 pN) = (2,050 ± 30) nm/s (Fig. S3A) (36,37). To ensure that deletion of pilV did not affect the speed of T4P retraction, we characterized T4P retraction in the ΔpilV strain and found v ΔpilV (8 pN) = (2,010 ± 30) nm/s (Fig.…”

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confidence: 99%

“…Finally, the binding and retraction probabilities of T4P to the beads are strongly reduced. WT gonococci would bind to and retract beads at a frequency of ∼1 s −1 (36), interfering with the quantification of DNA uptake.…”

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confidence: 99%

Kinetics of DNA uptake during transformation provide evidence for a translocation ratchet mechanism

Hepp

Maier

2016

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

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Horizontal gene transfer can speed up adaptive evolution and support chromosomal DNA repair. A particularly widespread mechanism of gene transfer is transformation. The initial step to transformation, namely the uptake of DNA from the environment, is supported by the type IV pilus system in most species. However, the molecular mechanism of DNA uptake remains elusive. Here, we used singlemolecule techniques for characterizing the force-dependent velocity of DNA uptake by Neisseria gonorrhoeae. We found that the DNA uptake velocity depends on the concentration of the periplasmic DNA-binding protein ComE, indicating that ComE is directly involved in the uptake process. The velocity-force relation of DNA uptake is in very good agreement with a translocation ratchet model where binding of chaperones in the periplasm biases DNA diffusion through a membrane pore in the direction of uptake. The model yields a speed of DNA uptake of 900 bp·s −1 and a reversal force of 17 pN. Moreover, by comparing the velocityforce relation of DNA uptake and type IV pilus retraction, we can exclude pilus retraction as a mechanism for DNA uptake. In conclusion, our data strongly support the model of a translocation ratchet with ComE acting as a ratcheting chaperone.

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“…For Neisseria gonorrhoeae and Myxococcus xanthus, retraction of T4P generates a high mechanical force exceeding 100 pN (8,9). Considering that T4P-related surface motility (also known as twitching motility) requires force generation (10,11) and that P. aeruginosa is capable of twitching motility (12), it is reasonable to assume that the T4P of P. aeruginosa generate mechanical force by retraction. However, the motor properties in the species have not been addressed.…”

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confidence: 99%

Role of Cyclic Di-GMP and Exopolysaccharide in Type IV Pilus Dynamics

et al. 2017

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For Pseudomonas aeruginosa, levels of cyclic di-GMP (c-di-GMP) govern the transition from the planktonic state to biofilm formation. Type IV pili (T4P) are crucial determinants of biofilm structure and dynamics, but it is unknown how levels of c-di-GMP affect pilus dynamics. Here, we scrutinized how c-di-GMP affects molecular motor properties and adhesive behavior of T4P. By means of retraction, T4P generated forces of ϳ30 pN. Deletion mutants in the proteins with known roles in biofilm formation, swarming motility, and exopolysaccharide (EPS) production (specifically, the diguanylate cyclases sadC and roeA or the c-di-GMP phosphodiesterase bifA) showed only modest effects on velocity or force of T4P retraction. At high levels of c-di-GMP, the production of exopolysaccharides, particularly of Pel, is upregulated. We found that Pel production strongly enhances T4P-mediated surface adhesion of P. aeruginosa, suggesting that T4P-matrix interactions may be involved in biofilm formation by P. aeruginosa. Finally, our data support the previously proposed model of slingshot-like "twitching" motility of P. aeruginosa. IMPORTANCE Type IV pili (T4P) play various important roles in the transition of bacteria from the planktonic state to the biofilm state, including surface attachment and surface sensing. Here, we investigate adhesion, dynamics, and force generation of T4P after bacteria engage a surface. Our studies showed that two critical components of biofilm formation by Pseudomonas aeruginosa, T4P and exopolysaccharides, contribute to enhanced T4P-mediated force generation by attached bacteria. These data indicate a crucial role for the coordinated impact of multiple biofilm-promoting factors during the early stages of attachment to a surface. Our data are also consistent with a previous model explaining why pilus-mediated motility in P. aeruginosa results in characteristic "twitching" behavior.

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Bacterial twitching motility is coordinated by a two-dimensional tug-of-war with directional memory

Cited by 93 publications

References 48 publications

Asymmetric distribution of type IV pili triggered by directional light in unicellular cyanobacteria

Asymmetric distribution of type IV pili triggered by directional light in unicellular cyanobacteria

Kinetics of DNA uptake during transformation provide evidence for a translocation ratchet mechanism

Role of Cyclic Di-GMP and Exopolysaccharide in Type IV Pilus Dynamics

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