A bifunctional ATPase drives tad pilus extension and retraction

Ellison, Courtney K.; Kan, Jingbo; Chlebek, Jennifer L.; Hummels, Katherine R.; Panis, Gaël; Viollier, Patrick H.; Biais, Nicolas; Dalia, Ankur B.; Brun, Yves V.

doi:10.1101/616128

Cited by 23 publications

(27 citation statements)

References 58 publications

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“…Upon DNA binding, which has been visualised for S. pneumoniae Com pili, but the receptor is yet to be identified (15), uptake will be initiated by filament retraction (14). Since there is no dedicated retraction ATPase, one possibility is that ComGA might be a bifunctional motor powering both extension and retraction like recently suggested for the T4cP motor (39). It would be interesting to image Com filaments dynamics and DNA-binding ability in live cells, using a labelling strategy that has recently enabled the visualisation of these steps for T4aP involved in competence in naturally competent diderm species (14).…”

Section: Discussionmentioning

confidence: 95%

The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

Sheppard

Berry

Denise

et al. 2020

Preprint

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AbstractType IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modelling analyses suggest that ComGC unusual structure is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.

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Section: Discussionmentioning

confidence: 95%

The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

Sheppard

Berry

Denise

et al. 2020

Preprint

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“…Isolates were then tested for changes in phage sensitivity to the pilus-dependent phage ΦCbK, and those exhibiting an alteration from wildtype sensitivity were sequenced to identify mutations. Whole genome sequencing and mutant identification was performed as described previously [35] with the exception that sequencing reads were mapped to the genome of C. crescentus NA1000 (NC_011916.1).…”

Section: Methodsmentioning

confidence: 99%

Surface Sensing Stimulates Cellular Differentiation inCaulobacter crescentus

Snyder

Ellison

Severin

et al. 2019

Preprint

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Cellular differentiation is a fundamental strategy used by cells to generate specialized functions at specific stages of development. The bacterium C. crescentus 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. Here, we find that surface sensing by the physical perturbation of retracting extracellular pilus filaments accelerates cell cycle progression and cellular differentiation. We show that physical obstruction of dynamic pilus activity by chemical perturbation or by a mutation in the outer membrane pilus pore protein, CpaC, stimulates early initiation of chromosome replication. In addition, we find that surface contact stimulates cell cycle progression by demonstrating that surface-stimulated cells initiate early chromosome replication to the same extent as planktonic cells with obstructed pilus activity. Finally, we show that obstruction of pilus retraction stimulates the synthesis of the cell cycle regulator, cyclic diguanylate monophosphate (c-di-GMP) through changes in the activity and localization of two key regulatory histidine kinases that control cell fate and differentiation. Together, these results demonstrate that surface contact and mechanosensing by alterations in pilus activity stimulate C. crescentus to bypass its developmentally programmed temporal delay in cell differentiation to more quickly adapt to a surface-associated lifestyle.SignificanceCells from all domains of life sense and respond to mechanical cues [1–3]. In eukaryotes, mechanical signals such as adhesion and surface stiffness are important for regulating fundamental processes including cell differentiation during embryonic development [4]. While mechanobiology is abundantly studied in eukaryotes, the role of mechanical influences on prokaryotic biology remains under-investigated. Here, we demonstrate that mechanosensing mediated through obstruction of the dynamic extension and retraction of tight adherence (tad) pili stimulates cell differentiation and cell cycle progression in the dimorphic α-proteobacterium Caulobacter crescentus. Our results demonstrate an important intersection between mechanical stimuli and the regulation of a fundamental aspect of cell biology.

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Section: Discussionmentioning

confidence: 95%

The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

Sheppard

Berry

Denise

et al. 2020

Journal of Biological Chemistry

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Type IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modeling analyses suggest that the unusual structure of ComGC is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.

show abstract

A bifunctional ATPase drives tad pilus extension and retraction

Cited by 23 publications

References 58 publications

The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

Surface Sensing Stimulates Cellular Differentiation inCaulobacter crescentus

The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

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